US1029082A - Pneumatic impact-tool. - Google Patents

Description

C. K. PICKLES.

PNEUMATIC IMPACT TOOL.

APPLICATION FILED 11136.27, 1900.

Patented June 11, 1912.

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PNEUMATIG IMPACT TOOL.

APPLICATION FILBDAUG. 27, 1900.

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UNITED STATES PATENT OFFICE.

CHARLES K. PICKLES, OF ST. LOUIS, MISSOURI, ASSIGNOR, BY MESNE ASSIGNMENTS, T0 CHICAGO PNEUMATIC TOOL COMPANY. OF CHICAGO, ILLINOIS, A CORPORATION OF NEW JERSEY.

PNEUMATIC IMPACT-TOOL.

Specification of Letters Patent.

Patented Julie 11, 1912.

Application filed August 27, 1900. Serial No. 28,247.

vnew-and useful Improvements in Pneumatic Impact-Tools, of,which the following is a specification.

The present invention relates to that type of portable pneumatic impact tools or hamluers in which a pneumatically operated `controlling valve is automatically controlled hy the impact piston in its movements.

The object of the present improvement is, in the main, to provide a simple, efficient and durable formation and arrangement of the parts of a pneumatic impact tool, which admits of the impact piston having a stroke greater than its own length; and with which an impact tool with any desired stroke can be provided with but very slight changes, and with a minimum length of the main outer casing or housing.

A further object of the present improvement is to provide a durable and effective means for fasteningthe hand grip or handle to the main casing or housing of the tool.

`I attain such objects by the construction and arrangement of parts illustrated in the accompanying drawings, in which:

Figure l, is a longitudinal sectional elevation at line @#13 Fig. 8, ofa` pneumatic impact tool or hammer, embodying the'present improvements, and illustrating the parts in a position in which the impact piston is just ending its forward stroke, with the controlling valve ready to make its rearward reversal movement. Fig. '2, a detail perspective view of the impact piston. Fig. 3, a similar view of the controlling valve. Fig. 4, a detail longitudinal section of the controlling valve and its accessories, with the parts in the samtl position as in Fig. I, with the impact piston nearing the end of its forward stroke, and the controlling valve ready to make its rearward reversal movement. Fig'. 5, a companion view to Fig. 4,

with the impact piston nearing the end of its rearward stroke, and the controlling valve ready to make its forward reversal movement. Fig. (3, a detail perspective view of the upper end of the main housing oi easing. Fig. T, a side elevation of the valve housing and its immediate accessories. Fig.

l S. a transverse section at line -w, Fig. 1. Fig. 9, an axial section of a modifedconstruction of the impact piston.

Similar numerals ofreference indicate like parts in the several views.

Referring to the drawings: 1, represents the main outer casing or housing'of the present impact tool, (also comrrionly designated the barrel or cylinder) having the usual contracted forward end for receiving the shank of the cutting chisel or other tool, anda screw threaded exterior at its rear end upon which is screwed a closure cap 2, which with the present invention applied to a pneumatic hammer may be the attaching hub portion or socket of the hand grip or handle of such pneumatic hammer.

3, is the impact piston or plunger, of the usual solid cylindrical form, and having at its forward end the usual impact extension 4; in the present improvement such piston is formed with the forward and rearward annular grooves or recesses 5 and 6, and forward -and rearward, longitudinal passages 7 and 8, connecting in an individual manner the grooves 5 and 6, with thelforward and rearward portions of the piston chamber` of the impact -tool for purposes hereinafter set forth. These portions are referred to in the claims for convenience as forward and rearward piston chambers respectively. In the practical construction of the impact piston it is immaterialvwhether the longitudinal passages T andS, above described be formed in the periphery of the piston as illustrated in Figs. 1, 4, and 5, or in the body of the same as illustrated in Fig. 9, their functions and actions being identical in either construction.

In the preferred form of the present invention as illustrated in the accompanying drawings, the cylinder proper for the impact piston 3, also constitutes a controlling valve t), by which the alternate reversal of the motive Huid pressure to the opposite ends of the impact piston is automatically at tained, and to this end the said cylinder and i valve 9, is capable of a limited longitudinal t movement in the mainouter casing 1, and i in the stationary valve block l0, that is ari ranged in the rear end of such-main' casing. In the particular construction shown the said cylinder and controlling valve 9, as a cylinder for the impact piston Will have a will involve features of construction as follows 11, is a forward guide head, fitting a. corresponding bore in the main housing- 1, and provided with -a series of radial ports 12, thatfare ada ted in the forward position of said control ing ,valve to r'e'gister the forward piston chamber with 'the lateral exhaust port 13, in the main housing to permit of an exhaust of the motive fluid from the forward piston chamber to the atmosphere, and in a rearward position of the valve to move out of register with the exhaust port 13, so that no inward suction can be induced therethrough by the .rearwardmovement of the impact piston. 14, are a series of radial ports arranged back of the radial exhaust ports 12, above described, and adapted to register `the interior of the combined valve and cylinder 9, with the longitudinally arranged annular chamber 15, between the inner wall of the main casin 1 and the periphery of said valve and cy inder, as shown in Figs. 1, 4 and 5. 16, are a series of radial ports arranged back of the radial ports 14, just described, and adapted to register the interior of the combined valve and cylinder 9, with the annular longitudinal chamberl 17, is a trap gate yor valve controlling communication between the rearward piston chamber and the annular chamber 15,

from such annular chamber into such rearward piston chamber; this valve may be located in any suitable position to effect the described result preferably on the exterior of the valve as shown in Figs. 1, 3, 4 and 5, and preferably consisting of a spring leaf closing over the series of ports 16; the object being to trap a portion of the expansible motive fluid from the rearward piston chamber in the annular chamber 15, for the purpose hereinafter set forth in the description of the operation of the present pneumatic yimpact tool. The relative arrangement of the series of ports 14 and 16, will be consonant with the arrangement of the annular grooves or recesses 5 and 6 of the impact piston, so that while the-outerseries 14, of said ports are in register with the outermost annular recess 5, of the piston, the rearward series 16 of said ports will be in re istcr with the rearward annular recess 6, o said piston, as illustrated in Figs. 1 and 4. 18, 1s an annular peripheral enlargement or head arranged to the rear to the series of radial ports 16, and constituting a piston head of some area, that has movement in an annular piston chamber of the valve block 10, as hereinafter set forth. 19, are one or more series of radial ports arranged. to the rear of the head or enlargement 18, and adapted in the rearward position of the controlling valve 9, to register the rearward piston chamber with the exhaust passages of the valve block, to permit of an exhaust of the motive fluid from the rearward piston chamber'to the atmosphere. In the preferred construction of the present invention as illustrated in the drawings, the rearmost set of the ports 19, will be arranged some distanceforward of the extreme rear end of the controlling valve, so that when said ports are closed by the impact piston as it nears the end of its rearward stroke, a body of the motive fluid will be confined behind the lpiston to act as a cushion therefor, and

which confined motive fluid in escaping to the atmosphere through the small longitudinal passages 8, of the piston, acts in avery perfect manner to effect a gradual check of the impact piston in its final backward movement. 20, is an offset extensionA that is adapted with the controlling valve in its rearward position, to cut off the Supply of motive fluid to the rear piston chamber; and 21, an annular shoulder formed by the j unction of the offset extension A20, andthe body of the valve, and which annular shoulder is exposed to constant motive fluid pressure, in order that the normal tendency ofthe controlling valve will be to move to its forward position in the absence of otherprevailing influences.

In the present construction the annular valve block 10, fits within a counterbore in and preventing a back flow of motive fluid the rear portion of the main housing 1, in which it is held in a stationary manner by the closure cap 2, heretofore described, through the instrumentality of the removable rea'r closure head 22, of the valve block, and an interposed spring 23. In addition tothe ab'ove described functions the main closure cap 2, also provides a main supply chamber 24, at the rear end of the impact tool, which is in constant communication with the source of motive fluid supply during the operation of the tool.

The annular valve block 10, of the present construction is formed with ports and passages as follows: 25, are a series of radial ports adjacent to the rear end of the valve block, which ports are adapted to in.- troduce motive fluid into the rear piston chamber, and are controlled by the rear end of the controlling valve 9. 26, are one or more series of radial ports arranged forward of the supply ports 25, and adapted in the rearward position of the controlling valve, to register with the exhaust ports 19, of such valve, to open communication between the rear piston chamber with thc atmosphere. 27, is an annular exhaust chamber connectingl with the exhaust ports 26, and with the main lateral exhaust Opeliing 28, that. extends through the main housing and the closure cap, to the atmosphere. j thumb lever 41, so as to regulate and limit 29, is a forward annular piston chamber, in which the annular enlargement or piston head 18, of the main controlling valve has movement in a fluid tight manner. 3U, is an exhaust passage connecting the rear end of the piston chamber 29, of the valve block with the main exhaust chamber 2T, of such 1 valve block, and adapted to prevent a rapid movement of the main controlling valve in either direction, and thus prevent a hammering action of such valve, as well as any recoil or flutter of the valve. 31, are one or more lateral ports, controlled by the head or enlargenient- 18, of the lnain controlling valve, and receiving motive fluid from a longitudinal passage 32, in the main housing, which extends to and is in Constant communication with the main motive fluid supply chamber 24.

While a practically efficient impact tool l can be constructed without the provisions of the ports and passages 31 and 3;?. just described,theiruseis preferred more especially in long stroke impact tools as affording a certain and reliable means for insuring a full backward stroke of the impact piston.

lVith the present invention applied to voke riveters and like uses. the rear end closure cap 2, will be in the form ot' an ordinalv closure cap screwing upon the rear end of the main housing to etlect a closure c!" the same; and with the invention applied to portable pneulnatic hammers as illustrated in Fig. 1 of the drawings. such cap piece 2, will preferably form an integral part of the hand grip cr handle SIE. such hand grip in the construction illl'lstrated` will comprise `features as t'ollows: IH, is a supv ply passages formed in one of the branches of the hand grip and communicating at one end with the lnain .supply chamber 24, in the rear end of the hammer, and at its other end provided with a projecting neck 35, which is internallyY screw threaded to receive the attaching nipple of the line of hose through which motive Huid is supplied to the impact tool, as usual in the present type of portable pnemnatic tools. 36, is a casing or bushing intersecting the supply passage 233. and forming the cylinder for the manually actuated piston valve 37, by means of which the supply of motive fluid to the tool is controlled; such valve is formed with an annular recess S8, adapted to register with oppositcly arranged ports 3H, in the valve casing 36, and by its movements control the admission ot' motive tluid to the tool. 4t), is a spring tending to mo\e the valve 37 into its closed position. 41, is a pivoted trigger or thumb lever having engagei'uent with one end of the throttle valve Sti, and adapted to impart an opening lnovemeut to the same. 42 is a temper screw or other like means arranged in the path of the the amount of cpening of the throttle valve IKT. to suit the particular work upon which the impact tool is employed. In the present in'iprovement the valve closing spring v10, is held in place b v a cup shaped bushing 13. screwing into the hand grip 33, in axial alinement with the valve 3T, and provided with a central orifice 44, and a disk shaped piece 45. which torms an abutment for the spring l0. and in addition thereto a spring impclled valve that normally closes thc opening 4l: with the described construction the nozzle ot' an oil can may be inserted into the opening 44, to displace the disk valve l5. and introduce a supply of oil into the small chamber between such valve and the adjacent end of the throttle valve 3T, which oil will flow into the passage 34, through the lateral port 34', when the throttle valve 3T, is in a closed position and in so flowing through the port 31, the oil will be in the path of the incoming motive fluid to be carried thereby to all the active parts ot'v the hammer mechanism.

The hand grip or handle 33, is locked against its jarring loose from its attachment to the main housing 1, by the following Y means: 46, is a spring dog moving radially in the attaching cap or hub portion 2, of the hand grip; the inner end of said dog being arranged to engage in a notch or recess '-LT. in the rear end of the main housing to lock the parts in their proper relative position. while its outer and reduced end is screw threaded and provided with an exterior handle 4S, by which said dog is capable of convenient rotation by hand. 4t), is a spring tending to torce said dog inwardly, and 50, is a bushing screwing into the hub or tap :2. and provided with a central screw threaded orifice in which turns the screw threaded outer end of the locking dog 46; the construction being such, that the spring dog must be rotated to etect an unlocking of the parts, the spring 49, tending to hold the said dog in its locking position against a jarring loose during a continued operation ot' the tool.

51, is the usual hardened bushing at the lower end of the. main housing, inserted in the usual manner from the exterior ot' said housing and constituting a holder and guide for the shank of the cutting or other tool.

52, is a hardened bushing inserted from within the interior of the main housing and tting against an ottset shoulder of the same. to constitute a guide for the extreme upper end ot the tool shank, and a removable abutment to receive the impact of the impact piston when the same has an-alniormal stroke dlle to the accidental removal of the tool shank from its proper position in said bushings.

The operation of the present pneumatic impact tool mechanism, is as follows: Starting with the impact piston and the controlling valve in the position illustrated in Figs. 1 and el. motive fluid contained inthe rear piston chamber, passes through the rearward longitudinal passage 8, of the piston into the rearward annular groove 6, and from thence through the lateral ports 16, and through the trap gate or valve 17, into the annular chamber 15, into which the saidl fluid pressure is trapped by the valve 17, and exerts its expansive force, upon the annular piston enlargement 18, of the main contro-lling valve to assist in forcing such valve into its rearward position, at the same time such fluid pressure passes through the lateral ports 14, into the forward annular groove 5, and through forward longitudinal passage 7, into the lower piston chamber to press against the lower annular end of the main controlling valve, to also aid in the rearward movement of such valve. Such pressure in the lower piston chamber also operates to impart the initial backward movement to the main impact piston 3,.

which rearward movement of the impact piston is completed, in my preferred construction illustrated in the drawings, by the valve enlargement 18, uncovering the inlet port 31, of the valve block to admit additional motive fluid into the lower piston' chamber through annular chamber 15 and ports 14, from the source of constant pressure supply. The rearward movement of the main controlling valve 9, is preliminary to the rearward movement of the impact piston, and said valve in moving into such rearward position cuts off the supply of motive fluid to the rearward piston chamber, and at the same time opens said rear piston chamber to the atmosphere through radial ports 19 and 26, chamber 27 and passage 28. In a simpler form of the present construction the inlet port 31, and passage 32, may be omitted and reliance placed upon the expansion of the body of motive fluid trapped in the annular chamber 15, as the sole means l for effecting the return or backward stroke of the impact piston. As the impact piston nears the end of its rearward stroke and after passing the rearmost series 'of radial ports 19 said piston will confine a portion of the motive fluid in the rear portion of the rearward pistonchamber, which motive fluid can only escape to the exhaust through the small longitudinal passage 8, of the piston and in consequence the final rearward movement of the piston is checked in a very even manner and the usual jarring of the tool due to a sudden rearward stoppage of the piston, is eliminated. With the impact piston lin its rearward position, 1ts forward annular groove 5', registers with the forward of exhaust ports 19, of the valve and the similar series of exhaust ports 26 of the valve block, and permits of an exhaust of the motive fluid from the forward piston chamber through the longitudinal piston passage 7 and the groove and ports 5, 19 and 26, just mentioned; with a relief of motive fluid pressure in the lower piston chamber and the consequent removal of pressure from the forward and larger pressure area of the main controlling valve 9, constant motive fluid pressure upon the smaller rearward area of controlling valve afforded by the annular shoulder 21, will again force said valve into its forward position to again open the exhaust ports 12 and 13 of the forward piston chamber, and the motive fluid supply to the rearward piston chamber to effect a fresh forward movement to the impact piston, and fresh cycle of the operations just described.

A novel and materialv feature of the present invention involves the admission by means of the piston of motive fluid pressure from the rear piston chamber into the forward piston`chamber.to eHect a backward stroke of said piston, in whole or part.

Having thusfully described my said invention, what I claim as new and desire to secure by Letters Patent, is:

1. In a pneumatic impact tool having a piston chamber, a piston formed with a pair of independent annular grooves and longitudinal passages extending to opposite ends of the piston, and adapted to control means for admitting motive fluid from the rear piston chamber to the forward piston chamber to effect a ret-urn movement of 'the piston, and means for so admitting the Inotive fluid substantially as set forth.

2. In a pneumatic impact tool, a piston formed with a pair of independent annular grooves and longitudinal passages extending to opposite ends of the piston, and adapted to control means for admitting motive fluid from the rear piston chamber to' the forward `piston chamber to effect a return movement of the piston, and means to prevent a reflux of motive fluid into the rear of piston chamber, and means for so admitting the motive 1fluid substantially as set forth.

3. In a pneumatic impact tool, the combination of a main casing having a piston chamber, a fluid actuated controlling valve, and an impact piston dapted to control means for admitting motve fluid from the rear piston chamber to the forward piston chamber to effect a return movement of the motive fluid from thelear piston Chamber to the forward piston chamber to impart an initial return movement to the piston, and means for so admitting the motive fluid substantially as set forth.

In a pneumatic impact tool, the combination of ay main casing having a piston chamber, i fluid actuated controlling valve. an impact piston adapted to control 1n x.ans for admitting motive fluid from the rear piston chamber to the forward piston chamber to effect a return movement of the piston, means for so admitting the motive fluid and means to prevent a reflux of motive fluid into the rear of piston chamber, substantially as set forth.

G. In a pneumatic impact tool, the combination of a main casing having a piston chamber, a fluid actuated controlling valve, an impact piston adapted to control means for admitting a limited quantity of motive fluid from the rear piston chamber Yto the forward piston chamber to impart an initial return moven'ient of the piston, means for so admitting the motive fluid and means t0 prevent a reflux of motive fluid into the rear of piston chamber, substantially as set forth.

7. ln a pneumatic impact tool, the combination of a main casing having a piston chamber. a fluid actuated controlling valve, and an impact piston formed with a pair of independent annular grooves and longitudinal assages extending to opposite ends of the piston, and adapted to control means for admitting motive fluid from the. rear piston chamber to the forward piston chamber to effect a return n'lovenient of the piston, and means for so admitting the motive fluid substantialhv as set forth.

8. l'n a pneumatic impact tool, the combination of a main lasing having a piston chamber, a fluid actuated controlling valve, an impact piston formed with a pair of independent annular grooves and longitudinal passages extending to opposite ends of the piston. and adapted to control means for admitting motive fluid from the rear piston chamber to the forward piston chamber to effect a return movement of the piston, means for so admitting the motive fluid and means to prevent a reflux of motive fluid into the rear of piston chamber, subst-antiall'v as set forth,

E). ln a pneumatic impact tool, the combination of a main casing having a piston chamber, a fluid actuated controlling \alve movable longitudinally of the easing. and an impact or hammering piston adapted to control means for admitting motive fluid from Athe source of pressure supply through the rear to the forward end of the valve to effect a reversal of the xsame and also to eontrel admission of motive fluid to the front piston chamber. and means for so admitting` the motive fluid: substantially as set,I forth.

l0. .ln a pneumatic impact; tool, the combination of a main casing having a piston chamber, a fluid actuated controlling valve, an impact piston adapted to control means for admitting motive fluid from the source of pressure supply through the rear. piston chamber to the larger area of the controlling valve to effect a reversal of the same, means for so admitting the motive fluid and means to preventy a flow of motive fluid from the valve chamber into the rear of piston chamber, substantially as set forth.

11. In a pneumatic impact tool, the com-- bination of a main casing having a piston chamber, a fluid actuated controlling valve, an impact or hammering piston adapted to control means for admitting motive fluid from the source of supply through the rear piston chamber to the forward end of the valve to effect a rearward movement of said valve to eut off communication of the forward piston chamber with the exhaust and. open the rear piston chamber to the exhaust, means for so admitting the motive fluid, and means for preventing the reflex of the motive fluid so admitted: substantially as set forth.

1Q. ln a pneumatic impact tool, the combination of a main casing having a piston chamber, a fluid actuated controlling valve, an impact piston adapted to control means for admitting motive fluid from the source of pressure supply through the rear piston chamber to the forward end of the valve to effect a rearward movement of said valve to cuty off communication of the forward piston chamber with the exhaust and open the rear piston chamber to the exhaust, means for so admitting the motive fluid and means to prevent a reflux of motive fluid into the rear of piston chamber, substantially as set forth.

13. ln a pneumatic impact; tool, the combination of a main casing having a piston chamber. a fluid actuated controlling valve movable longitudinally of the casing, and an impact or hammering piston adapted to control means for admitting motive fluid from the source of supply through the rear piston chamber to the forward end of thc valve to effect. a rearward movement of said valve to open communication between the source of constant pressure and .the forward piston chamber, said piston being movable within said Yalve, and means for so admitting the lnotive fluid; substantially as set forth.

14. ln a pneumatic impact tool. the combination of a main easing having a piston chamber. a fluid actuated controlling valve, an impact piston adapted to control means for admitting motive fluidfrom the source of supphv through the rear piston chamber to the forward end of the valve to effect a rearward moveu'ient of said valve to open communication between the source of constant pressure and the forward piston chamber, means for so admitting the motive fluid and means to prevent a reflux of mot-ive fluid into the rear of piston chamber, 4substantially as set forth.

15. In a pneumatic impact tool, the combination of a main casing having a piston chamber, a fluid actuated controllin valve, and an impact piston adapted in is rear, ward travel to control means for opening the forward piston chamber to the exhaust to permit a forward movement of the controlling valve, said piston being constructed to admit motive fluid to the forward piston chamber, and means for so admitting the motive fluid; substantially as set forth.

16. In a pneumatic impact tool, the combination of a main casing having a piston chamber, a fluid actuated controlling valve, an impact piston adapted in its rearward travel to control means for opening the forward piston chamber to the exhaust to permit a forward. movement of the controlling valve to admit motive fluid to the rear piston chamber and close communication between the source of constant pressure and the forward piston chamber and in its forward travel to admit pressure to the valve to shift the same in the other direction, means for preventing lthe reflex of the pressure so admitted, and means for so admitting the motive fluid; substantially as set forth.

17. Ina neumatic impact tool in which the stroke of) the piston is in excess of length, the combination of a main casing, a cylindrical .hammering piston the diameter of which is uniform as to pressure areas, and a valve actuated by the motive fluid pressure controlled by the Vmovement of the iston and having ports governed thereby, su stantially as set forth.

18. In a pneumaticmpact tool in which the stroke of the piston is in excess of its length, the combination of a main casing, a cylindrical hammering piston the diameter of which is the same at opposite ends, and a fluid actuated controlling valve exposedI to constant pressure on one end .and to intermittent pressure on the other end, said valve having ports governed by the piston, substantially as set forth.

19. In a pneumatic impact tool, the combination of a main casing, a fluid actuated controlling valve having ports governed by the piston in its reciprocations .and an impact piston having `a stroke in excess of its chamber, a fluid actuated controlling` valve, ly :hitting the motive Huid length and adapted to control means for admitting motive fluid from the source of supply to the forward end of the valve to effect a reversal of the same and to the forthe latter, substantially as set forth.

20. In a pneumatic impact tool, the coman impact piston having a stroke in excess of its length and adapted tocontrol means for admitting motive fluid from the source of supply to the forward end of the valve to effect a reversal of the s ame, and means to prevent a reflux of motive fluid into the rear ofpiston chamber, and means for so admitting the motive fluid substantially as set forth. y I l.

21. In a pneumatic impact toolthe combination of a main casing having a piston chamber, a fluid actuated controlling valve 'movable longitudinally ofthe casing, and

an impact or hammering piston having a stroke in excess of its length and adapted to control means for admitting motive flui from the source of supply through the,pis

ton chamber to the forward end of theuvalve to effect a reversal of the same, means for so admitting the motive fluid, andmeans for preventing a reflex of the motive fluid so ad* mitted; substantially as set forth. v

22. In a pneumatic impact tool, thecombination of a main casing having a piston chamber, a fluid actuated controlling valve, an impact piston having a. stroke in excess of its length and adapted to control means for admitting motive fluid from the source of supply through the rear piston'chamber to the forward end of the valve to effect a reversal of the same, means for so admitting the motive fluid and means to prevent a reflux of motive fluid into the rear of piston chamber, substantially as set forth.

23. In a pneumatic impact tool, the-combination of a -main casing having a piston chamber, a fluid actuated controlling valve movablelngitudinally of the casing. and an 'impact or hammering piston having a stro'ke in excess of its length and adapted to control means for admitting motive fluid from'the source of supply through the piston chamber tothe forward end of the valve to efi'ect'a rearward movement of said valve to cut off communication of the forward portion of the piston chamber with the exhaust and to open the rear piston chamber to the exhaust, and means for so admitting the motive fluid, said piston controlling the admission of motive fluid to thefront end of the piston chamber; substantially as set forth. t l

24. In a pneumatic impact tool, the combination of a main casing having a piston chamber, a fluid 4actuated controlling valve, an impact piston having a stroke in excess of its length and adapted to control means .for admitting motive fluid from the source ofsupply through the rear piston chamber to the forward end of the valve to effect a rearward movement of said valveto out off communication of the forward piston chamber with the exhaust and open the rearv p1sbination 0f a main Casing having a piStOIl i ton chamber to the exhaust, means forso adand means to prey motive fluid to the valve to reverse it, and

- .to the forward end of the valve to effect a rearward movement of said valve to open communication between the source of con stant pressure and the forward piston chamber, means for so admitting the motive fluid, and means to prevent-a reflex of the motive fluid into the rear of the piston chamber, substantially as set forth.

26. In a pneumatic impact tool, the com.

bination of a main casing having a piston chamber, a. fluid actuated controlling valve, an impact piston having a stroke in excess of its length and adapted to control means for admitting motive fluid from the source of supply through the rear piston chamber to the forward end of the valve to effect a rearward movement of said valve to open communication between the source of constant pressure and the forward piston chamber, means for so admitting the motive fluid, and means to prevent a reflux of motive fluid into the rear of piston chamber, substantially as set forth.

27. In a pneumatic impact tool, the combination of a main casing having alpiston chamber, a fluid actuated controlling valve,

and an impact piston having a stro-ke in excess of its length and having a groove adapted in the pistons rearward travel to control means for opening the forward piston chamber to the exhaust to permit a forward movement of the controlling valve, said piston being arranged to adm1t the motive fluid to the valve to reverse it, and means for so admitting the motive fluid; substantially as set forth.

Q8. In a pneumatic impact tool, the combination of a main casing'having a piston chamber, a fluid actuated controlling valve, and an impact piston having a stroke in eX- cess of its length and carrying means adapted in its rearward travel to control means for opening the forward piston chamber to the exhaust to permit a forward movement of the controlling valve, to admit motive fluid to the rear-piston chamber, and close communication between the source of constant pressure and the forward piston chamber, said piston being arranged to admit the means for so admitting the 'motive fluid; substantially as set forth.

29. In a pneumatic impact tool, the combination of a main casing having apiston chamber, a fluid actuated controlling valve,

and an impact piston having a stroke in excess of its length and adapted to control means for admitting motive fluid from the rear piston chamber through the piston to the forward piston chamber to effect a return movement of the piston, and means for so admitting the motive fluid, substantially as set fort-h.

30. In a pneumatic impact tool, the combination of a main casing having a piston chamber, a fluid actuated controlling valve, and an impact piston having a stroke in ex 4cess of its length and adapted to control means for admitting a limited quantity of motive fluid from the rear piston chamber through the piston to the forward piston chamber to impart an initial return movement to the piston, and means for so admitting the motive Huid, substantially as set forth.

31. In a pneumatic impact tool, the colnbination of a main casing having a piston chamber, a fluid actuated controlling valve, and an impact'piston having a stroke in excess of its length and formed with a pair of independent annular grooves and longitudinal passages extending to opposite ends of the piston, and adapted to control means for admitting motive fluid from the rear piston chamber to the forward piston chamber to impart an initial return movement 5 to the piston and means for so admitting the motive fluid, substantially as set forth.

32. In a pneumatic impact tool, the combination of a main casing having a piston chamber, a fluid actuated controlling valve, an impact piston having a stroke in excess of its length and adapted t0 control means for admitting motive flhid from the rear piston chamber to the forward piston cham` ber to effect a return movement of the piston, means for so admitting the motive fluid, andy means to prevent a flow of motive fluid from the valve chamber into the rear of piston chamber, substantially as set forth.

In a pneumatic impact tool, the combination of a main casing having a piston chamber, a fluid actuated controlling valve, an impact piston having a stroke in excess of its length and adapted to control means for admitting a limited quantity of motive fluid from the rear piston chamber to the forward piston chamber to impart an initial return movement to the piston, means for so admitting the motive fluid, and means to prevent a flow of motive fluid from thc valve chamber into the rear of piston chamber, substantially as set forth.

34. In a pneumatic impact tool, the combination of a main casing havin a pistonchamber, a fluid actuated control ing valve having an annular opcn'ended form andronstituting the cylinder for the impact'piston, and an impact piston adapted to control means for admitting motive fluid from the rear piston chamber to the forward fpiston.

having an annular open ended form and constituting the cylinder for the impact piston, and anvimpact piston adapted to'control means for admitting motive fluid from the source of supply through the rear piston chamber to the forward end of the valve v to effect a rearward movement of said valve to open communication between the source of constant pressure and the forward piston chamber, and means for so admitting the motive fluid, substantially as set forth.

45. In a pneumatic impact tool, the combinatien of a main casing having a piston chamber, a .fluid actuated controlling valve having an annular open ended form and con stituting the cylinder for the impact piston, an impact piston adapted to control means for admitting motive fluid from the source of supply through the rear piston chamber to the forward end of the valve to'effect a rearward movement of said valve to open communicatio-n between the source of constant pressure and the forward piston chamber, means for so admitting the motive fluid and means to prevent a reflux of motive fluid into the rear of piston chamber, substantially as set forth.

4G. In a pneumatic impact tool, the combination of a main casing having a piston chamber, a fluid actuated controlling valve having an annular open ended form and constituting the cylinder for the impact piston, and an impact piston adapted in its rearward travel to control means for opening the forward piston chamber to the exhaust to permit a forward movement. of the controlling valve, and means for so admitting the motive fluid, substantially as set forth.

47. In a pneumatic impact tool, the combination of a main casing havingxa piston chamber, a fluid actuated controlling valve having an annular open ended form and constituting the cylinder for the impact piston, and an impact piston adapted in its rearward travel to control means for opening the forward piston chamber to the exhaust to permit a forward movement of the controlling valve to admit motive fluid to the rear piston chamber and close communication between thevsource of constant pvessure and the forward piston chamber, and means for so admitting the motive fluid, substantially as set forth.

48. In a pneumatic impact tool, the combination of a main casing, a fluid actuated controlling valve having an annular open ended form and constituting-the cylinder for the impact piston, and an impact piston having a stroke in excess of its length, and arrangedto control the pressure to and from the valve for operating the latter; substantially as set forth..

49. In a pneumatic impact tool, the combination of a main casing, a fluid actuated controlling valve having un annular open ended form and constituting the cylinder for the impact piston and exposed to constant pressure on one end and to intermittent pressure on thc other end, and an impact piston having a stroke in excess of its length,

substantially as set forth.

50. In a pneumatic impact tool, the combination of a main easing having a piston chamber, a Huid actuated controlling valve having an annular open ended form and constituting the cylinder for impact piston, an impact piston having a stroke in excess of its length and adapted to control means for admitting motive fluid from the source of su l throu h the rear iston chamber to PP y g P the forward end of the valve to effect a reversal of the same, and means for so admitting the motive fluid, substantially as set forth.

51. In a pneumatic impact tool, the combination of a main casing having a piston chamber, a fluidactuated controlling valve having an annular open ended form and constituting the cylinder for impact piston, an impact piston having a stroke in excess of its length and adapted to control means for admitting motive fluid from the source of supply through the rear piston chamber to the forward end of the valve to effect a reversal of the same, means for so admitting the motive flllud and means to prevent a reflux of motive fluid into the rear of piston chamber, substantially as set forth.

52. In a pneumatic impact tool, the combination of a main casing having a piston chamber, a fluid actuated controlling valve having an annular open ended form and constituting the cylinder for the impact piston, and an impact piston having a. stroke in excess of its length and adapted to control means for admitting motive fluid from the source of supply through the rear piston chamber to the forward end of the valve to effect a rearward movement of said valve to cut off communication of the forward piston chamber with the exhaust and open the rear piston chamber to the exhaust, and means for so admitting the motive fluid, substantially as set forth.

53. In a pneumatic impact tool, the combination of a main casing having a piston excess of its length and adapted to control 12.0

means for admitting motive fluid from the source of supply through the rear piston chamber to the forward end of the valve to effect a rearward movement of said valve to cut olf communication of the forward piston 12 chamber with the exhaust and open the rear` piston chamber to the exhaust, means for so admitting the motive fluid and means to pre vent a reflux of motive fluid into the rear of pistou chamber, substantially as set-forth. 1:30

54..In a pneumatic impact tool, the comi piston, and an impact piston having a. stroke bination of a main casing having a piston I in excess of its length and adapted to conchainber, a fluid actuated controlling valve stituting the cylinder for the impact pison, and an impact piston having a stroke in ex- Cess of its len th and adapted to control means for admitting motive fluid from the l source of supply through the rear pieten chamber to the forward end of the valve 1.o effect a rearward movement of said valve, to open con'imunication between the source of constant pressure and the forward piston 'chamber, and means for so admitting the motive fluid, substantially as set forth.

55. In a pneumatic impact tool, the combination of a main casing havingr a piston chamber, a fluid actuated controlling valve having an annular open ended form and constituting the cylinder for the impact piston, an impact piston having a stroke in excess of its length and adapted to control means for admitting motive fluid from' the source of supply through the rear piston chamber to-theI forward end of the valve to ell'ecta rearward movement of said valve, to open communication between the source of constant pressure and the forward piston chamber, means for so admitting the motive fluid and means to prevent a reflux of motive fluid into the rear of piston chamber, substantially as set forth.

56.A In a pneumatic impact tool, the combination of a main casing havin a piston chamber, a fluid actuated control ing valve having an annular open ended form and constituting the cylinder' for the impact piston, and an impact piston having a stroke in excess of its length and adapted in its rearward travel to control means for opening the forward piston chamber to the exhaust to permit a forward movement of the controlling valve, and means for so admitting the motive. fluid, substantially as set forth.

57. In a pneumatic impact tool, the combination of a main casing havin a .piston chamber, a fluid actuated control ing valve having an annular o n ended form and constituting the cylin er for the impact piston, and an impact'piston having a stroke in excess of its length and adapted in its rearward travelto control means for opening the vforward piston chamber to the exhaust to permit a forward -movement of the controlli valve to admit motive fluid to the roar piston chamber and close communication between .the source of constant pressure and the forward piston chamber, and means for so admittin the motive fluid, substantially as set fort.

58. In a pneumatic impact tno1the combination of ,a main casing havin a piston chamber, a fluid actuated contro ing valve having an annular open endediuform and constituting the cylinder for the impact f trol means for admitting motive fluid from having an annular open ended form and conthc rear uiston chamber to the forward piston cham )er to eflect a return movement of the piston, and means for so admitting the motive fluid, substantially as set forth.

59. In a pneumatic impact too-l, the combi- 2 nation of a main casing having a piston` chamber, a fluid actuated controlling valve havingl an annular open-ended form and constituting the cylinder for the impact piston, and an impact piston having a stroke in excess of its length and adapted to control means for admitting alimited quantity of motive fluid from the rear piston chamber to the forward piston chamber to effect an initial return movement of the piston, and 'means for so admitting the motive fluid, substantially as set forth.

60. In a pneumatic impact tool, the com bination of a main casing having a piston chamber, a fluid actuated' controlling valve having an annular o en ended form and constituting the cylin er for the impact piston, and an impact pist-on having a stroke in excess of its length and formed with a pair of independent annular grooves and longitudinal passages extending to opposite ends of the iston, and adapted to 'control means for a mitting motive fluid from the rear piston chamber to the forward piston chamber to impart an initial return move-- ment tothe piston, and means for so admitting the motive fluid, substantially as set forth.

61. In a pneumatic impact `tool, the combination of a main casing havin a piston chamber, a fluid actuated control ing valve having an annular open ended form and constituting the cylinder` for the impact piston, an impact piston having a stroke in excess of its len h and adapted to control means for admitting motive fluid from the rear iston chamber to the forward piston cham r to effect a return movement of the piston, means for so admitting the motive fluid, and means to prevent a reflux of m0- tive fluid into the rear of piston chamber, substantially as 'set forth.

62. In a'pneumatic impact tool, the combination of a main casing having a piston chamber, a fluid actuated controlling valve having an annular open ended form and constituting the cylinder for the impact pist0n, an impact piston having a stroke in excess of its length -and adapted to control means for admit-tin a limited quantity of motive fluid from t e rear piston chamber to the forward piston chamber to impart an initial return movement to piston, means for admitting the mot-ive fluid, and means to prevent a reflux of motive fluid into the rear of piston chamber, substantially as set forth.

63. In a .pneumatic impact tool, the combination of a main casing having a piston passages extending lbination of a main casing chamber, a fluid actuated controlling valve, an impact piston adapted to control means for admitting motive fluid from the rear piston chamber to the forward piston chamber to effect a return movement of the piston, means for so admitting the motive fluid, and means carried by the controlling valve and adapted to prevent a reflux of motive fluid into the rear of piston chamber, substantially as set forth.

64. In a pneumatic impact tool, the combination of a main casing having a piston chamber, a. fluid actuated controlling valve, an impact piston formed with a pair of' independent annular grooves and longitudinal to opposite ends of the piston, and adapted to control means for admitting motive fluid from the rear piston chamber to effect a return movement of the piston, means for so admitting the motive fluid, and means carried by the controlling valve and adapted to prevent a reux of motive fluid into the rear of piston chamber, substantially as set forth.

65. In a pneumatic impact tool, the comhaving a piston chamber, a fluid actuated controlling valve, an impact piston adapted to control means for admitting motive fluid from the source of pressure supply through the rear piston chamber to the forward end of the valve to effect a reversal of the same, means for so admitting the motive llilid and means carrie by the controlling valve and adapted to prevent a reflux of motive fluid into the rear of piston chamber, substantially as set forth.

66. In a pneumatic impact tool, the. combination of a main casing having a piston chamber, a fluid actuated controlling valve, animpact piston adapted to control means for admitting motive fluid from the source of pressure supply through the rear piston chamber to the forward end of the valve to effect a rearward movement of said valve to cut off communication of the forward piston chamber with the exhaust and open the rear piston chamber to the exhaust, means for so admitting the motive fluid and means carried by the controlling valve and adapted to prevent a reflux of motive fluid into the rear of piston chamber, substantially as set forth.

67. In a pneumatic impact tool, the combination of a main casing having a piston chamber, a fluid actuated controlling valve,

an impact piston adapted to control means' for admitting motive fluid from the source of supply through the rear piston chamber to the forward end of the valve to effect a rearward movement of said valve to open communication between the source of cronstant pressure and the forward piston chamber, means for so admitting the mot-ive fluid and means carried bythe controlling valve and adapted to prevent a reflux of motive fluid into the rear of piston chamber, substantially as set forth.

68. In a pneumatic impact tool, the combination of a main casing having a piston chamber, a fluid actuated controlling valve, an impact piston having a stroke in excess of its length and adapted to control means for admitting motive fluid from the source of supply through the rear piston chamber to the forward end of the valve'to effect a reversal of the same, means for sov admitting the motive fluid and means carried by the controlling valve and adapted to prevent a reflux of motive fluid into the rear of piston chamber, substantially as set forth.

69. In a pneumatic impact tool, the combination of a main casing having a piston chamber, a fluid actuated controlling "valve, an impact piston having a stroke in excess of its lengt-h and adapted to control means for admitting motive fluid fromI the source of supply through the rear piston chamber to the forward end of the valve to effect a rearward movement of said valve to cut off communication of the forward piston chamber with the exhaust and open the rear piston chamber to the exhaust, means for so admitting the motive fluid and means carried by the controlling valve and adapted to prevent a reflux of motive fluid into the rear of piston chamber, substantially as set forth.

70. In a pneumatic impact tool, the combination of a main casing having a piston chamber, a fluid` actuated controlling valve, an impact piston having a stroke in excess of its length and adapted to control means for admitting motive fluid from the source of supply through the rear piston chamber to the forward end of thevalve to effect a rearward movement of said valve to open communication between the source of constant'pressure and the forward piston ch amber, means for so admitting the motive fluid and means carried by the controlling valve and adapted to prevent a reflux of motive fluid into the rearV of piston chamber, substantially as set `forth.

71. In a pneumatic impact tool, the combination of -a main casing having a piston chamber, a fluid actuated controlling valve, an impact piston having a stroke in excess of its length and adapted to control means for admitting motive fluid from the rear 72. In a pneumatic impact tool, the 4combination of a main casing having a piston chamber, a fluid actuated controlling valve having an annular open endeed form and constituting the cylinder for the impact piston,

lis

' valve to effect af reversal an impact piston adapted to control means for admitting motive fluid from the rear piston chamber-to the forward piston chamber to effect a return of the piston, means for so admitting the mot-ive fluid and means carried by the controlling valve and adapted to prevent a reflux of motive fluid into the rear of piston chamber, substantially as set forth.

73. In a pneumatic impact tool, the combination of a main casing having a piston chamber, a fluid actuated controlling valve haying an annular open ended form and constituting the cylinder for the impact pis ton, an impact piston adapted to control means for admitting motive fluid from the source of pressure supply through the rear piston chamber to the forward end of the of the same, means for so admitting the motive fluid and means carried by the controlling valve and adapted to prevent a reflux of motive fluid into the rear of piston chamber, substantially as set forth.

74. In a pneumatic impact tool, the combination of a main casing having a piston chamber, a fluid actuated controlling valve having an annular open ended form and constituting the cylinder for the impact piston, an impact pistonadapted to control means for admitting motive fluid from the source of supply through the rear piston chamber to the forward end of the valve to effect a rearward movement of said valve to cut off communication of the forward piston chamber with the exhaust and open the rear piston chamber to the exhaust, means for so admitting the motive fluid and means carried by the controlling valve and adapted to prevent a reflux of motive fluid into the rear of piston chamber, substantially as set forth. 75. In a pneumatic impact tool, the combination of avmain casing having a piston chamber, a fluid actuated controlling valve having an annular open ended form and constituting the cylinder for the impact piston, an impact piston adapted to control means for admitting motive fluid from the source of supply through the rear piston chamber to the forward end of the valve to effect a rearward movement of said valve to open communication between the source of con'- stant pressure and the forward piston chamber, means for so admitting the motive fluid and means carried by the controlling valve and adapted lto prevent a reflux of motive fluid into the rear of .piston chamber, substantially as set forth.

7G. In a pneumatic impact tool, the combination of a main casing having a piston chamber/a fluid actuated'controlling valve having an annular openl ended form and constituting the cylinder for the impact piston, an impact pist-on having a stroke in excess of its length and adapted to control means for admitting motive fluid from the source of supply through the rear piston chamber to the forward end of the valve to effect a reversal of the same, means for so admitting the motive fluid and means carried by the controlling valve and adapted to prevent a reflux of motive fluid into the rear of piston chamber, substantially as set forth.

77. In a pneumatic impact tool, the combination of a main casing having a piston chamber, a fluidgactuated controlling valve having an annular open ended form and constituting the cylinder for the impact piston, an impact piston having a stroke in excess of its length and adapted to control means for admitting motive fluid from the source of supply through the rear piston chamber to the forward end of the valve to effect a rearward movement of said valve to cutoff communication of the forward piston chamber with the exhaust and open the rear'piston to the exhaust, means for so admitting the motive fluid and means carried by the controlling valve and adapted to prevent a reflux of motive fluid into the rear of piston chamber, substantially as set forth.

78. In a pneumatic impact tool, the combination of a main casing having a piston chamber, a fluid actuated controlling valve havingan annular open ended form and constituting the cylinder for the impgact piston, an im act piston having a stroke in excess of its l ength and adapted to control means for admitting motive fluid from the source of supply through the rear piston chamber to the forward end of the valve to effect a rearward movement of said valve to open communication-between the source of constant pressure and the forward piston chamber, means for admitting the motive fluid and means carried by ythe controlling valve and adapted to prevent a reflux of mot-ive fluid into the rear of piston chamber, substantially as set forth.

79. In a pneumatic impactv tool, the combination of a main casing having a piston4 chamber, a fluid actuated controlling valve having an annular open ended form and constitutin the cylinder for t-he impact piston, an impact piston having a stroke in excess of its length and adapted to control means for admitting motive fluid from the rear piston chamber to the forward piston chamber to effect a return movement of the piston, means for admitting the motive fluid and means carried by the controlling valv. and adapted to prevent a reflux of motive fluid into the rear of piston' chamber, substantially as set forth.

80. In a pneumatic impact tool of the character herein described, the' combinationv of the main housing, the annular valve block, a closure head for the rear end of the valve block, a closure cap for the rear end of the main housing and a spring interposed between said closure head and closure. cap, substantially as set forth.

8l. In a pneumatic impact tool of the character herein described, the combination with the main housing provided with an interior shoulder at its lower end, of an interior bushing bearing against said shoulder, and an exteriorly inserted bushing vfitting the reduced forward bore of the main housing, substantially as set forth.

82. In a pneumatic impact tool of the character herein described, the combination of the main housing, the annular valve block, a closure cap for the rear end of the main housing, a spring dog adapted to move radially in the closure cap, and engage a recess in the rear end of the housing, and a bushing lscrewing to the closure cap and provided with a screw threaded orifice, the spring dog being formed with a screw threaded outer end adapted to engage in the aforesaid bushing and with a handled outer end, substantially as set fo-rth.

83. In a pneumatic hammer, the combination of a cylinder, a hammering piston therein, and a single valve structure for controlling the admission and release of pressure to and from the cylinder for reci-procation of the piston and operated by pres sure controlled thereby, said valve being a sleeve open at its front end for the passage of the, piston and of greater length than the piston and forming the chamber in which the latter reciprocates.

84. In a pneumatic hammer, the combination of, a cylinder, a hammering piston therein, and a single, valve structure for controlling the admission and release of pressure to and from the cylinder for reciprocation of the piston and operated by pressure controlled thereby, said valve being of greater length than the piston and movable longitudinally of the cylinder and consisting of a sleeve concentric of the piston and open at its, front end for the passage of the piston.

85. In a pneumatic hammer, the combination of a cylinder, a hammering piston therein, a single valve structure for controlling the admission and release of pressure to and from the piston chamber, said piston controlling the admission of pressure vto the front end of the piston chamber, and said cylinder having at its front end an exhaust port controlled by said valve which moves thereover for exhausting the front end of the piston chamber after the return of the piston is initiated.

86. In a pneumatic hammer, the combination of a cylinder, a piston therein having a length of stroke greater than its own length, and a single valve structure for controlling the admission and release of pressure to and from the cylinder and of greater length than the piston, said valve structure in both directions wholly by fluid pressure controlled by such piston, said valve structure being of substantiall the same length as the bore of the cylin er and consisting of a sleeve open at its front end for the passage of the piston and concentric of such piston to form the piston chamber proper for the latter.

88. In a pneumatic hammer, the combination of a cylinder, a piston therein, and a valve concentric of the piston and exposed on one side to constant pressure and on the other side to pressure controlled by the piston in its reciprocations, said piston controlling the admlssion of motive Huid to the Afront end of the piston chamber. f

89. In a pneumatic hammer, the combination of a cylinder, a piston therein, and a valve concentric of the piston and exposed on one side to constant live pressure and on the other side to pressure intermittently admitted by the piston in its reciprocations, said valve controlling the motive fluid to the rear end of the piston chamber and said piston to the front end thereof.

90. In a pneumatic hammer, the combination of a cylinder, a Ipiston therein, and a differential valve moved in one direction b the live Huid pressure and in the other d1- rection by Huid pressure controlled by the piston, said valve formingl a chamber in which the piston reciprocates and which togethei` with the cylinder has rear exhaust ports arranged at such distance fromv the rear end thereof to provide a space for conlining the Huid pressure upon the return or rearward stroke of the piston, thereby cushioning the latter.

91. In a pneumatic hammer, the combination of a cylinder, a piston therein, and a differential valve concentric of the piston and moved rearwardly by pressure admitted by the piston against its larger pressure area and forwardly by live or normal pressure acting constantly against its smaller pressure area, said valve having a port governed by the piston and through which the pressure is so admitted.

92. In a pneumatic hammer, the combination of a cylinder, a piston therein, and'a hollow differential valve of substantially the same length as the cylinder bore and forming the chamber in whichv the piston reciprocates, said valve being differential and moved in one direction by live or normal fluid pressure and in the other direction by fluid pressure controlled'by the pist0n.

93. In a pneumatic hammer, the comblnation of a cylinder having a pressure chaiuber for the valve, a piston in the cylinder,

' the return ofy such-pressure.

' 94. In a pneumatic hammer, the combination of a c linder having a pressure chamber extending longitudinally and intermediatethe length of the valve, a piston in the cylinder, and a valve coperating with said pressurechamber which is located between the inner walls of the 4cylinder and the valve, said piston being. arranged to control fluid pressure to said. chamber for movingthe valve in one direction bythe expansion of the fluid pressure admitted to and conlined kwithin said chamber. V

95. In a pneumatichammer, the combination of a cylinder lhaving a longitudinal bore or chamber, a differential shell valve sliding therein, and a piston whose diameter equals the internal diameter of the valve and which is arranged to travel. therewithin, said cylinder having a pressure chamber formed between its inner wall and the valve and adapted to contain fluid pres- "sure to move the valve in one direction by the expansion thereof, said valve being sub- ]ected to fa constant pressure upon its smaller pressure area and to an intermittent pressure upon its.other or larger pressure area as controlled by the piston.

96. In a pneumatic hammer, the combina tion of\ a cylinder, a piston therein, and formed as a sleeve `within which the piston reciprocates, said c linder havinga pressure chamber locate between its innerwall and the valve and adapted to contain fluid pressure to move the valve in one direction.

. 97. In a pneumatic hammer, the combination of a cylinder, a piston therein and a valve comprising a sleeve in which the piston reciprocates, said cylinder having a pressure chamber formed between its inner wall and the valve and `adapted to contain fluid pressure,'and said` valve being differential with its larger preure area exposed to said pressure chamber.

98. In a pneumatic hammer, the combination of a cylinder, a piston, a `valve of greater length than the pistn and within which the latter reciprocates, said cylinder having a pressure chamber formed between its inner wall and the valve and adapted to contain fluid pressure, and said valve being differential with its larger pressure area exposed to said pressure chamber and with its smaller pressure area exposed' to constant live or normal pressure. v

99. In a pneumatic hammer, the com; bination of a cylinder, a piston therein, and formed as a sleeve within which the piston reciprocates, said cylinder having a pressure chamber located between its inner wall and the valve and adapted to contain fluid pressure, and said valve being diferential with its larger pressure area exposed to said pressure chamber and its smaller pressure area to constant live or normal pressure.

100. In a pneumatic hammer, the combination of a cylinder, a valve for admitting Huid pressure to the rear end of the cylinder to mpel the piston forward, and a piston reciprocable-within the cylinder and carrying means, which in coperation with the valve, are arranged to control the admission of pressure from the rearward to the forward end of the piston for its return or rearward stroke.

lOl. In a pneumatic hammer, the combination of a cylinder, a valve for admitting liuid pressure to the rear end. of the cylin-4- der to mpel the piston forward, and a piston reciprocable within the cylinder and having passages for the liuid pressure for returning the piston.

102. In a pneumatic hammer, the combination' of a cylinder, a vali/e therein for governing the fluid pressure to and from the rearward end of the cylinder, and a piston reciprocable in the cyiinder and r..i.rr,ing means for governing the fluid pressure to the forward end. .of the cylinder.

103. In a pneumatic hammer, the coinbn'eation of a cylinder, a valve therein for gmferning the fluid pressure to and from the rearward end of the'cylindcr, such cylinder having a pressure chamber between it and the valve, and a piston rcciprocable in the cylinder and governing the fluid pressure therethrough to the forward end of the cylinder to mpel the piston on its return or rearward stroke.

104. In a pneumatic hammer, the combination of a cylinder, piston reciprocablc therein, and a valve therein controlling fluid pressure to opposite ends of the cylinder, said piston .having means for admitting fluid pressure to the forward end of the cylinder preliminarily to the admission of fluid pressure thereto' by the valve.

105. In a pneumatic hammer, the oenbination of a cylinder, a piston reciprocable therein, and a valve therein controlling fluid pressure to opposite ends of the cylinder, said piston having means for admitting fluid pressure from the cylinder or piston chamber to the forward end of the cylinder preliminarily to the admission of liuid pressure thereto by the valve.

106. In a pneumatic hammer, the combination of a cylinder, a iston reciprocable therein, and a valve therein controlllng fluid pressure to opposite ends of the cylinder,

said piston having means lor admitting fluid pressure to the forward end of the inder, said piston having means for admitting fluid presslire from the rear end to the .forward end of the cylinder and also against the valve to shift the latter rearwardly to admit live fluid pressure to the forward end of the cylinder and thereby complete the return of the piston initiated by the pressure admitted by the piston.

108. In a pneumatic hammer, the combination of a cylinder, a valve therein for governing the fluid pressure to and from A the rearward end of the cylinder, and a piston reciprocable in the cylinder and having ports and passages which, in cooperation with the valve, are arranged to communicate between its opposite ends.

109. In aI pneumatic hammer, the coinbination of a cylinder, a valve therein for governing the fluid pressure to and from the rearward end of the cylinder, and a piston reciprocable in the cylinder and having ports.and passages which are adapted to coperate'with the valve and communicate between opposite sides of the piston when thelatter is at the end of its forward stroke.

110. Ina pneumatic hammer, the combination of afcylinder having exhaust ports located at such distance from the rear end as to be closed by the piston in its rearward stroke, a piston reciproeable in the cylinder and having a small port for the gradual escape of fluid pressure trapped by it on its rearward stroke after closing the exhaust ports, -aiid a valve governing the pressure to and from the cylinder.

111. In a pneumatic hammer, the coin- 'bination of a cylinder having exhaust ports located at such distance from the rear end as to be elo-sed by the piston in its rearward stroke, a piston reciprocable in the cylinder, a valve governing the pressure to and from the cylinder, and means for permitting the gradual escape of pressure trapped in the rear end of the cylinder by the piston on its rearward stroke after closing said exhaust ports.

112. In a pneumatic hammer, the combi nation of a cylindei, a piston reciprorable therein, and a differential valve for controlling the pressure and arranged concentric of` the piston, the smaller pressure area of such valve being constantly exposed to live fluid pressure and the larger pressure area toffluid pressure alternately admitted thereagainst, said valve consisting of a sleeve iii which the piston travels.

113. In a pneumatic hammer, the combination of a cylinder, a fluid actuated controlling valve therein, exposed on one end to constant pressure, said valve being of a greater length than thepiston, and on the other end to intermittent pressure, and an impact piston reciprocable within the valve.

111. In a pneumatic hammer, the combination of a cylinder, a Huid actuated controlling valve therein, forming the piston chamber and exposed on one end to coiislant pressure and on the other end to`intermittent pressure, and an impact piston reciprocable in the piston chamber of such valve.

115. In a pneumatic hammer, the combi-A nation of a cylinder, a iluid'actuated controlling valve therein forming the piston chamber and exposed on one end to constant pressure. and on the other end to intermittent pressure, and an impact piston reciprocable in the piston chamber of such valve, and having a lengthof stroke greater than its own length, said valve being substantially of the same lengtlras said piston stroke.

11G. In ay pneumatic hammer, the combination of a cylinder, a piston reciprocable therein, and a valve having an enlargement forming a pressure area, one side of which is constantly exposed to exhaust through an always open `port to atmosphere and the nati'on of a cylinder, a piston reciprocable therein, and a valve having intermediate its length an enlargement against one side of which the pressure is intermittently admitted to move the valve rearwardly and whose other side is constantly exposed` to atmosphere, the rear end of such valve being constantly exposed to live pressure and having a port governed by the piston and through which thc pressure is thus intermittently admitted.

11S. In a pneumatic hammer, the combination of a cylinder, a piston reciprocable therein, and a valve forming a chamber for the piston to travel in and having intermediate its length an enlargement against one side of which the pressure is intermittently admitted to move the valve rearwardly, the rear end of such ,valve being constantly exposed to live pressure and the forward end of thc valve being intermittently exposed to pressure.

11S). In a pneumatic hammer, the combination of a cylinder, a piston reeiprorablc therein, and a valve having intermediate its length an enlargement against one side of which the pressure is intermittently'admitted to move the valve rearwardly, the rear end of such valve being constantly exposed to live pressure and the forward end of the valve being intermittently exposed to pressure controlled by the piston.

120. In a pneumatic hammer, the combination of a cylinder, a piston reciprocable therein, and a valve having an enlargement movable in` a chamber in the cylinder and exposed on one side to atmosphere through an always open port and on the other side to pressure intermittently admitted thereagainst, the rear end of said valve being exposed to constant live pressure and the front end thereof being exposed to the front end of the cylinder or piston chamber.

121. In a pneumatic hammer, the combination of a cylinder, a piston reciprocable therein, and a valve having intermediate its length an enlargement movable in a chamber in the cylinder and exposed on one side to pressure intermittently admitted thereagainst, by the piston, the rear end of said valve being exposed to constant live pressure tending to hold the valve to forward position, said valve having a port controlled by the piston through which the pressure is thus intermittently admitted.

122. 'In a pneumatic hammer, the combination of a cylinder, a piston reciprocable therein, and a valve having an enlargement movable in a chamber in the cylinder and exposed on one side to pressure intermittently admitted thereagainst, and said pislton having suitable ports and passages for so admitting the pressure intermittently v against said enlargement and also for admitting such pressure intermittently to the forward end of the valve.

123. In a pneumatic hammer, the combination of a cylinder, a piston reciprocable therein, a hollow valve movable in line with the piston and in Which the latter is arranged to travel, said valve having an entermittently admitted to move the valve in one direction, and means for moving the valve in the opposite direction.

124. In a pneumatic hammer, the 'combination of a cylinder, a piston reciprocable therein, a hollow valve movable in line with the piston and in which the latter is arranged to travel, said valve having an enlargement. against which the pressure is intermittently admitted to move the valve in one direction, and constantly exposed to live pressure tending to move itin the opposite direction.

125. In a pneumatic hammer, the combination of a cylinder, a piston reciprocable therein, a hollow valve in which the piston travels and which controls the pressure to opposite ends of the cylinder, one end of .said valve being constantly exposed to live pressure tending to move it in one direction, and means for shifting the valve in the opposite direction.

126. In a pneumatic hammer, the combination of a cylinder, a piston reciprocable therein, a hollow valve in which the piston travels and which controls the pressure to opposite ends of the cylinder, said valve having differential pressure areas, the smaller one of which is constantly exposed to live pressure and the larger one of which is subject to pressure intermittently acting thereagainst.

127. In apneumatic hammer, the combination of a cylinder, a piston reciprocable therein, a hollow valve in which the piston travels and which controls the pressure to opposite -cnds of the cylinder, said valve having differential pressure areas, the smaller one of which is constantly exposed to live pressure and the larger one of which is .intermittently acted upon by pressure controlled by the piston.

Signed at Chicago, Ills., this 22nd day of August 1900.

CHARLES K. PICKI 1E S.

fitnesses ROBERT BURNS, HENRY A. N o'rr.

ted tomove the valve rearwardly, the rear i end of such valve being ,constantly exposed to live pressure and the forward end of the valve being intermittently exposed to pressure controlled by the piston. I

120. In a pneumatic hammer, the combination of a cylinder, apiston reciprocable therein, and a valve having an enlargement.

movable ina chamber in the cylinder and exposed on one side to atmosphere through.

r an always'open port and on the otherside valve being exposed to'constant live pres-y vsii to pressure intermittently admitted thereagainst, the rear end of said valve being exposed to constant live pressure and the front end thereof beingvexposed to the front end of the cylinder or piston chamber.

121. In a pneumatic hammer, the combi-v --nation of a cylinder, a piston reciprocable therein, and a valve having intermediate its length an enlargement movable in a chain-` ber in the cylinder and exposed on onek side to pressure intermittently admitted thereagainst, by the piston, the rear end of said so admitting the pressure intermittently againstsaid enlargement and also Afor ad' mitting such pressure intermittentlyto the forward'end of the valve. y

123. In a .pneumatic hammer, the combination of a cylinder, apiston reciprocable therein, a hollow valve movable in line with the Vpiston and in which the latter is arranged to travel, said valve having an entermittently admitted to move the valve in one direction, and means for movingthe valve inthe opposite dlrectlon.

124'. In a pneumatic hammer, the combination of a cylinder, a piston reciprocable therein, a hollow valve movable inline with the piston andA in which the latter is arranged to travel, said valve having an enlargement against which the pressure is intermittently admitted to movethe valve in one direction, and constantly exposed to livc pressure tending to move it in the opposite direction. v

125. In a pneumatic hammer, the combi* nation of a cylinder, a piston reciprocable therein, a hollow valve in which the piston travels and which controls the pressure to opposite ends of the cylinder, one end of .said valve being constantly exposed to live pressure tending to move it in one direction, and means for shifting the valve in the opposite direction.v

126. In a pneumatic'hammer, the combi- .fnation of a cylinder, a piston reciprocable therein, a hollow valve in which the piston travels and which lcontrols the pressure to opposite ends of the cylinder, said valve having differential pressure areas, smaller one of which is constantly vexposed to live pressure and the larger one of which is subject to pressure intermittently acting thereagainst. y

127. In apneumatic hammer, the combithe Anation of a cylinder, a piston reciprocable A therein, a hollow valve in which the piston travels and which controls the pressure to opposite -ends of the cylinder, said valve having differential pressure areas, the

smaller oneof which is constantly exposed to live pressure and the larger one of which is .intermittently acted upon by pressure controlled by the piston.

Signed at Chicago, Ills., this A22nd day of August 1900.

CHARLES K. PICKLE S.'

litnesses RcBER'r BURNS, HENRY A. N o'r'r.

Copies of Vthis patent may be obtained for ve cents each, by addressing the Commissioner of Patents,

in the Patent O 'flice [SEAL] requiring correction as follows: Page, 4,

Washington, D. C. i It is hereby certified that in Letters Patent No. 1,029,082, granted J une'11, 1912, upon the application of Charles K. Pickles, of St. Louis, Q ment in Pneumatic Impact-Tools,

Missouri, for an improveerrors appear in the printed specification line104, after the word tooliinsert the words 'a/ving @piston citar/ader; page 12, line 86, after the word piston insert the word chamber; page 16, after' line 44,i I

nse'rt the syllables and words largement against witte/t t/e pressure s rt-,Hand that the said Letters Patent should be read with these-corrections therein thatv the same may conform to the record of the case Signed and'sealed this 22ndiday ofl October, A. D., 1912.

C. C. BILLINGS,-

Acting Cbmmz'ssz'mtcw of Patents.'

of tl case' l' 5 Corrections

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