US2655901A - Pneumatic hammer - Google Patents

Description

Oct. 20, 1953 N. BROWN PNEUMATIC HAMMER 2 Sheets-Sheet 1 Filed May 12, 1951 /4 fsa /34 /95 204 f faz Oct. 20, 1953 N. BROWN 2,655,901

PNEUMATIC HAMMER Patented Oct. ZO, 1953 UNITED STATES FATNJT GFFICE 2,655,901 PNEUMATIC HAMMER Lowell N.- Brown, Overland, Mo

Application May 12, 1951, Serial N0.. 225,981

(Cl. 1...?/.1.18.)v

1 Claim. 1

` maintains an incorporated pressure oontrol deviee in open oeoiiiorl, as io understood:

is a general rule, devices of this type'are of a eorliigiireilen resembling a pistol. grid are illus also commonly known as pneumatic guns. rivet guns and so on.

is lo Sov. they irreliide o. horlelle, portieri associated with a barrel portion substantially normal thereto, so that the gun may be,u so to speak, directed at any selected angle, as is well understood-- As will appear, the primary objeot oi my inven-` tion is to provide a pneumatic hammer which is more ecient, more povverful, and at the same time lighter weight than those heretofore in use.

Features include simplicity of design; mounting o f the air control valve assembly in a portion oi the handle to facilitate operation thereof, and also removal thereof as a unit for cleaning pur-,- poses when necessary; a replaceablev cylinder niemeer in the form of e ease hardened. meiellio Sleeve oelooiell to be proiettile@ lille ille borrel portieri. es o eorisooirenee of Wliioll ille leiter may be formed of light weight metal without weakening 'ille Construction; all@ .nolfel mail@ @Slimlsive to the control valve assembly for effecting the intermittent reciprocations of the hammer blow delivery member.

rlheore are other features and advantages inmoreno. moho invention `vloroh will oo ooo. forro in the description to follow, referenee beine lied, also io the oeeomporlvine drawings Wlliell illustrate irl detail, the oreferrerl Construction ef my inverliion.-

.Ill .Soviel drawings:

Fie, .l is a top plan View of e pneumatic hom.- mer comprising the present invention;

Fig. 2 is a side elevational view thereof;

Fig. 3 is a front elevational view thereof;

Fig. 4 is a central vertical sectional View there: of on an enlarged scale, the view being taken along line .ll-,4 of Fig. 1.; v

Fig. 5 is a further enlarged reproduction of a fragmentary portion of Fig', 4, an included disl; or Wafer member occupying 'an alternate position; s Fig. 6 is a horizontal sectional view taken on line 5 6 of Fig. 4;

Fig. 7 is an enlarged reproduction of a frag.- mentary portion of Fig. 6; an included Clisi;` or Wafer member being shown in an alternate posi: tion corresponding to Fig. 5;

Figs. 8, 9 and 10 are vertical sectional views taken respectively on lines Bef-,8. 8 3, and lil-I9 in Fig,r l, the scale of said views corresponding to that ofFigs. 4 and 6;

Fig, l1 is a top plan view of the barrel portion of the device and certain elements associated therewithj Fig. 1 2 is a bottom plan view of Fig. 1l;

Fig, 13 is an elevational view, vvith a pair of dowel pins in section, taken on line [3f- I3 of Fig. 1l, the scale corresponding to that of Figs'. 4 and 6; v

Figs. 1,4,` l5 and 16 are similar views taken respectively on lines M-f-lll, l5r|5, and lli-:i6 of Fig. 1 1;

Fig. 17 is an elevational View of a thin metallic disk or Wafer adapted to fluctuate WflGIltlfie invention is in operation;

Fig. i8 is an edge View thereof;

Fig. 19 is a rside elevational View of a hollow` cylinder adapted to be presstted into the bore of the barrel member included in the invention;

Fig. 29 is a horizontal sectional vieW taken through the handle portion of the gun online Ztl-2Q of Fig. 4, an incorporated air control valve assembly being portrayed in closed position; and

Fie. 2l is e reprodrlotion oli en enlarged seeley o f the major portion of Fig. 20, said control valve assembly being portrayed in open position.l

in Figs. 1 through 4, the pneumatic hammer comprising my invention is designated as a Whole, by numeral 30.

lt includes barrel portion generally designated 3.2; a handle portion generally designated 34; a manually operable air pressure controllas-y sembly 38; a composite assembly generally designated 38 responsive to assembly 35 for automatically effecting intermittent reciprocatory'niovef moois of o blow delivery piston member' genero y designated il.; ,all insert cylinder 4?: elle other associated and incorporated parts as will appear.

Borrel portieri 3.2 eolfleiste of o body portieri the forward .end of which is preferably tapered as ai i5 to terminate .in a concentric extremity 48 of reduced peripheral diameter as shown.

The rear end of ysaid barrel is externally l threaded as. at i0, and the barrel has formed 3 therein intermediate its ends, an annular shoulder 52, as seen to best advantage in Figs. 4 and 6.

The body of the barrel has formed therein a longitudinal socket the internal diameter of which is of `a size to accommodate a pressit insertion of cylinder 42. A counterbore 56 of smaller diameter is formed in the forward end portion of said barrel, thus providing a shoulder 53 against which the forward end face B0 of said cylinder is situated.

As shown particularly in Fig. 4, the body portion of the barrel has also formed therein a rst or forward pair of diametrically opposite exhaust ports 62, and a second or rearward pair of diametrically opposite exhaust ports 64.

The internal conguration of handle portion 3d is seen to best advantage in Fig. 4. Said handle includes a lower hand grip portion 56 integral with an upper hollow cylindrical portion 68, the latter being internally threaded as at 10, whereby to engage the externally threaded end portion 50 of barrel member 52.

Rearwardly beyond threaded portion 70, Yan annular air pressure chamber 'i2 is provided as shown, said chamber being in uid communication with a passageway 'i0 leading therefrom and to a smaller annular air chamber B, the latter being located in handle portion 56.

As shown in the drawings, said chamber l5 is in horizontal alinement with an air pressure intake chamber T8 the diameter of which is reduced, whereby to provide an annular shoulder 80 for a purpose to appear.

Air under pressure from a source (not shown), is continuously supplied to chamber 'i8 via passageway 82, inlet B4, and a flexible air line 85, the latter being shown by broken lines in Fig. 4. and inlet 34 being threaded internally for the reception of a suitable fitting, such as suggested in broken lines at S8.

The manually operable air control valve assembly 36 is illustrated in detail particularly in Figs. 20 and 21. This Valve assembly controls the flow of air pressure from intake chamber i8 into chamber 75, as will now be described.

Included in the assembly 3B is a nger piece 90 which is cupshaped as shown, and preferably provided with a rounded bottom wall portion 92 and an annular ange portion 94. Rigidly secured by welding, peening, or otherwise, to the finger piece 50 centrally thereof, is one end of a valve stem 95. The other end of said stem has an enlarged head portion .9s terminating in a reduced portion |00, which after passing through a central aperture provided in an annular cupshaped washer |02, is peened over to rigidly secure the latter to said head portion as shown in Fig. 21.

Interposed about the head portion 98 in the cavity provided in the washer, is va ring |04 of semi-rigid rubber or the like, the preferable material being neoprene. As shown in the drawings, the exposed portion of said ring projects laterally to the left beyond the Washer I 02, for a reason to appear.

Numeral I 05 indicates generally a hollow valve plug member of assembly 35. It includes a body portion |08 terminating at its right end in a cylindrical portion IIB the external diameter of which is slightly smaller than the internal diameter of chamber 1S, and at its left end in a cylindrical portion H2 the external diameter of which is considerably smaller than the internal diameter of annular flange S4.

Adjacent the right end I0, body |08 is provided with an abutment flange |24 adapted, when the plug is in position, ito engage against shoulder 80. Adjacent its left end H2, body |08 is provided with an abutment flange I |6, adapted to be engaged by the flange 94 when the valve assembly is in fully open position, as will appear. The peripheral configuration of flange I I6 is noncircular, it preferably being hexagonal as shown.

Intermediate its ends, plug |05 is provided with a threaded portion ||8 engageable with an internally threaded bore |20 provided in handle portion 66.

Numeral |22 designates a longitudinal bore in plug |06; numeral |243 is a similar counterbore; numeral |26 a shoulder or seat thus formed to accommodate one end of a compression spring |28, the other end of which bears against the bottom wall 92 of member 50, whereby the valve stern 96 is normally biased yto the left to force said projecting portion of ring IM to seat itself against portion |I0 of plug |06, as illustrated in Fig. 20.

A cylindrical segment |30 of the hollow plug body, which segment extends through chamber i6, is provided with a pair of diametrically opposite ports |32 whereby fluid communication obtains between passage |24 and said chamber.

From the foregoing, it should be obvious that the air control valve assembly 36 comprises a composite unit which may be quickly removed and replaced with ease, by the application of a wrench, or similar tool, to noncircular flange portion H5 of plug |06.

The composite assembly 38, responsive to air pressure under control of Valve assembly 30 whereby to effect the intermittent reciprocations of piston-hammer member 40, will now be described with particular reference to Figs. 4 through 9, and Figs. 13 through 16.

Said assembly comprises a pair of disk members, maintained in peripherally alined relation by means of dowel pins, and disposed concentrically with the pressure chamber 72 in portion 68 of the handle, as reference to the drawings will demonstrate.

Thus, it is seen particularly in Figs. 4 and 6, that the right hand face of rst or rear disk member |34 is in intimate contact with a solid vertical wall |36 partly defining chamber i2; that the left hand face is in intimate contact with the right hand face of the second, or forward disk member |38; that the left hand face of the latter is in intimate contact with end face |40 of barrel member 32, and end face |42 of the insert sleeve or cylinder 42; and that the peripheral diameters of said disks |30 and |38 are identical, and less than the internal diameter of chamber 12.

As illustrated in the several views of the drawings, member |34 has formed therein a central longitudinal bore |44, in fluid communication with a pair of diametrically opposite transverse passageways |46, the latter in turn being in fluid communication with a pair of longitudinal bores 48 on a radius concentric with bore |44.

At right angles to passageways |45, member |34 is provided with a pair of diametrically opposite passageways |50 opening into chamber 12. Intersecting each passageway |50 is a longitudi nal bore |52 also on a radius concentric with bore |44 aforesaid.

The left hand face of disk member |34 has a circular recess |54 formed therein, and said member is also provided with a circular flange |56 which surrounds bore |44.

A pair of short longitudinal ports |58 lead from each passageway |50 into the recess |54. It is noted that although one such port would seem to be sufficient, it has been found that a better distribution of air pressure is afforded by the dual port arrangement.

Complementary disk member |38 has formed therein a central longitudinal through bore or passageway |60; a pair of longitudinal through bores |62 on a radius concentric with bore |60; a pair of diametrically opposite bores |64 each opening into chamber 12; a pair of longitudinal bores |66 intersecting bores |64, and on a radius concentric with bore |60; a rst circular recess |68 formed in the right hand end face oi said disk member; a second smaller recess concentric therewith; a rst circular flange |12 surrounding recess |10; a second circular ange |14 surrounding passageway |60; and a pair of short longitudinal ports |16 leading from each of the bores |64 to recess |10.

It is not deemed requisite to describe in detail the alinement and registry of these ports and passageways at this time, since the arrangement should be clear from the drawings and the description of operation to follow later.

Obviously however, it is important that the disposition of disk relative to disk |34 and to adjacent insert cylinder 42 be definitely and precisely maintained.

To this end, a pair of diametrically opposite dowel pins |18 pass through holes |66 in member |38, and project on either side thereof to enter sockets |82 and |84 provided respectively in the end of cylinder 42 and member |34. In this connection, attention is also directed to Figs. 11 f.

and 12.

The complementary disk members, thus positioned, are rigidly clamped between wall |36 and the rear end faces |40 and |42 respectively, of the cylinder 42 and barrel member 32. Rigidity is by means of a removable semi-rigid split collar |92, the forward Ainturned end portion of which engages against annular shoulder 52, as Fig. 4 demonstrates.

Shown per se in Figs. l'1 and 18, is a metallic wafer |94, the periphery of which is slightly smaller than circular recess |68 of disk |36. Thus, as a comparison of Figs. 4 through 7 will demonstrate, said wafer is free to vibrate or nuctuate from a position sealing bore |44 to a position sealing the rear end of passage |60, and vice versa.

The longitudinal bore |95 of cylinder 42 is counterbored as at |96 to provide a tapered or frusto-conical shoulder portion |98 adjacent the forward end of said cylinder.

In alinement with exhaust ports 62, cylinder 42 has formed therein a pair of diametrically opposite ports 200; and in alinement with exhaust ports 64, said cylinder has formed therein a similar pair of ports 202.

Formed in the periphery of said cylinder, are a pair of longitudinal air passageways 204, which as best seen in Fig. 6, form continuations of aligned bores |62 and |48. Adjacent shoulder |68, cylinder 42 has formed therein a pair of 16 openings 205 each of which establishes'nuid communication between one OI seid passageways `204, and bore |95.

Piston member 40 is of solid construction. and

includes a body portion 206 slideable in cylinder 42, a frusto-conical portion 208 adapted to strike against shoulder |08 as will appear, and a cy1in The marmer in which a mechanic would ein- 'ploy this pneumatic hammer is believed to be 15| apparent. Guiding the shank or handle portion "of a selected tool with one hand, and gripping the handle 34 with the other, finger manipulation of the control valve assembly 36 will eilect the delivery of rapidly successive intermittent blows to 20= the said tool, as will be explained.

The shank portion of a chisel C is suggested by broken lines in Figs. 2 and 4, it being of course understood that other selected tools may be employed, the only requisite being that the shanks vof such tools are of a diameter smaller than that of counterbore 56.

It. will be assumed that air under pressure is constantly supplied .to intake chamber 18 from a source not shown, delivery being Vvia flexible line 8G, inlet 84, and passage 82.

It will also be assumed that valve assembly 36 is in its normal or closed position illustrated in Figs. 4 and 20. In this position, flange ||4 is seated against shoulder 80, and ring |04 is maintained in sealing position against the end H0 of plug |06 by means of spring |28, so -that the air under pressure is confined in said chamber 18.

Release of said pressure, for delivery via chamber 16 and passage 14 to 'air chamber 1,2, is effected by pressure applied to finger piece whereby to compress spring |28 and propel the assembly composed or elements 98, |00, |02 and |04 to the right and away from plug end H0, as portrayed in Fig. 2,1.

As a result, so long as the valve assembly is maintained open, a constant flow of pneumatic pressure is directed into chamber 12 via counterbore |24, ports |32, air chamber 16, and passage 14.

YIt is noted at this time, that the provision of hexagonal flange ||6, serves a dual purpose. That is to say, it provides for easy removal of the entire assembly 36, and in addition, provides an abutment for ilange 94, whereby, regardless of pressure unconsciously or otherwise applied `by the lingers of the operator, the flow QI air power continues until removal o f nnger pressure automatically and positively shuts off the air supply as spring |28 expands.

Assuming now that the air control assembly -66 is open, and that the blow delivery piston 40 is in the broken line rearward position thereof portrayed in Fig. 4, Wafer |94 will be momentarily in the position portrayed in Figs. 5 and 7, thus .sealing port |44.

Consequently, the air pressure passes from stroke thereof, the impact Abeing absorbed by shoulder I 98 at such time.

That is to say, should the resistance to the cutting action of tool C be normal, then piston 40 will strike shoulder |98 as the hammer portion 2 i0 of said piston drives the tool forwardly, as is understood. However, should the resistance offered be great, the piston stroke may be arrested short of its maximum travel, as should also be understood.

In either case, piston 40 after having been driven forwardly past exhaust ports 202--64, continues to advance by momentum, and after striking a blow against the end of tool C, automatically rebounds rearwardly a suicient distance for the frusto-conical portion 208 to pass beyond pressure intake openings 205.

Immediately following the instant when body portion 205 of the piston uncovers openings 205, the air pressure, now reversed as will be explained, forces said piston rearwardly until portion 209 thereof passes exhaust ports 2ML-52. the piston continuing to advance thereafter by momentum to the momentary broken line position thereof portrayed in Fig. 4, whence it is again driven forwardly.

The reciprocatory movements of piston 02 are so rapid that the hammer blows are struck with what may be termed machine-gun velocity, but on the other hand, manual release of finger piece 90 will automatically effect the cessation of said movements, as should be clear from the earlier description of valve assembly 36.

The confined but otherwise unsupported wafer |94 controls the reversal of pressure application to alternate ends of the piston 42.

In other words, as pressure enters cylinder 02 via passage |60 as described, wafer |96 is automatically maintained in the position thereof illustrated in Figs. and 7.

However, as the rear end of piston 40 passes exhaust ports 202-64, the pressure supply in chamber 72 is exerted against the right hand face of said wafer via passages |50 and ports |56, whereby to force said wafer leftwardly to the position thereof illustrated in Figs. 4 and 6.

As a result, passageway |60 becomes sealed, and simultaneously pressure is suppled to passageways 204 via recess |54, bore |44, transverse ports |66, longitudinal bores |48, and passages |62, as particularly apparent from an inspection of Fig. 6.

This reversal of pressure flow is coincidental with the rebounding action of piston 42, so that instantaneously after body portion 206 uncovers openings 205, pressure entering cylinder 42 by way of said openings is directed against the forward end of the piston to force it rearwardly.

Instantaneously after the forward end of piston body 206 passes rearwardly beyond exhaust ports 200-62, the further movement of said piston by momentum again causes wafer |94 to move to the right for a repetition of the cycle, as should be manifest,

From the foregoing description and reference to the drawings, it should be clear that the invention provides a compact, highly eicient mechanism adapted to achieve its objectives.

Whatrdaimis:

In a device yof the character described, said device including a reciprocable hammer `blow delivery pisto-n member: means for intermittently and automatically reversing the application of pneumatic air pressure from the front to the rear end of said piston, and vice versa; said means comprising a composite assembly incl-uding a pair of disk members maintained in peripherally alined relation by means of dowel pins with a metallic wafer therebetween; the rst or right disk member having formed Ytherein a central longitudinal bore, a first pair of diametrically opposite transverse passageways in fiuid communication therewith, a pair of longitudinal bores on a radius concentric with said central bore each in fluid communication with one of the transverse passageways, a second pair of diametrically opposite passageways at right angles to said first pair, a pair of longitudinal bores also on a radius concentric with said central bore and each intersecting one of said second pair of passageways, a circular recess in the left hand face portion, an annular flange surrounding the left end of said central bore, and at least one short longitudinal port leading from each of the second pair of passageways to said recess; the second or left hand disk member having'formed therein a central longitudinal through passageway, a pair of longitudinal through bores on a radius concentric with the central bore, a pair of diametric-ally opposite bores, a pair of longitudinal bores on a radius concentric with said central bore each intersecting one of said diame'trically opposite bores, a first circular recess in the right hand face por-tion, a second smaller recessconcentric therewith, a rst circular flange surrounding the latter recess, a second circular flange surrounding the 40 right end of said central through bore, and at least one short longitudinal port leading from each diametrically opposite bore to said second recess; the metallic wafer being of a sizeslightly smaller than the first circular recess in the right hand face portion of the second disk member, and larger than the circular recess in the left hard face portion of the first disk member aforesai LOWELL N. BROWN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,352,191 Henig Sept. 7, 1920 1,465,770 Shaii Aug. 21, 1923 1,612,783 Gartin Dec. 28, 1926 1,923,205 Hoffman Aug. 22, 1933 2,053,676 Nell Sept. 8, 1936 2,221,100 Lear Nov. 12, 1940 2,443,894 Craze June 22, 1948 2,471,604 Boyer May 3l, 1949 2,472,352 Van Sittert June 7, 1949 FOREIGN PATENTS Number Country Date 129,175 Great Britain July l0, 1919 379,665 Germany Aug. 27, 1923

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