US2682658A - Valve actuating means for pneumatic staple driving machines - Google Patents

Description

'www' July 6, 1954 v. T. HoEFLlcH 2,682,658

VALVE ACTUATING MEANS F'OR PNEUMATIC STAPLE DRIVING MACHINES Filed May l1, 1.950 2 Sheets-Sheet 1 mi f JNVENTOR ,Wfff 7.' edf/Lz /cf/ July 6, 1954 v T. Hor-:FLlcl-x 2,682,658

VALVE ACTUATING MEANS FOR PNEUMATIC STAPLE DRIVING MACHINES m JNVENTOR. Hf W J7-a@ 7:' H05/QM# Patented July 6, 1954 UNITED STATES ATENT OFFICE VALVE ACTUATIN G MEANS FOR PNEUMA'I'IC STAPLE DRIVING MACHINES 10 Claims. 1

This invention relates to machines for driving staples, especially to so-called .tackers, and more particularly to such machines anranged for air or pneumatic operation.

The primary object of the present invention is to generally improve air operated staple drivers, and especially tackers. A more particular object of the invention is to provide a .tacker which requires no extra valve operating handle, and which instead is automatically and conveniently operated in response to pressure on the regular handle `of the tacker. Thus the Isame natural motion and manner of use which would anyway be employed in order to hold the device against the wall or surface into which the staple is being driven functions also to operate the air valve and so to drive the staple.

In accordance with a further feature and object of the invention, the unit is made relatively simple,l light, and inexpensive by mounting the air cylinder on the forward end of the magazine with the staple driver connected directly to the piston, and 'by mounting the valve housing drectly -on the cylinder, with the housing and its air hose nipple extending collaterally of the magazine, the housing and nip-ple being enclosed within a hollow handle extending from the rear end of the magazine to a point over the cylinder.

Further objects of the invention ycenter about the valve mechanism for controlling .the staple driving operation. A single housing is preferably provided with oppositely faced valve seats, and a valve stem extending therethrough carries both an inlet valve disc and an exhaust valve disc, the latter `being normally open and the form-er being normally closed by the air supply pressure itself. The exhaust valve is closed when the inlet valve is opened, and vice versa. In accordance with an object and feature of the present invention the exhaust valve is closed before the inlet valve is opened, and in accor-dance with a further and ancillary object of the invention the inlet valve is abruptly and widely opened to help produce a sudden drive of the staple. This is of particular benefit when, as here disclosed, the staple driving mechanism is used for tacking purposes,

To accomplish the foregoing objects, and other more specic objects which hereinafter appear, my invention resides in the staple driving, valve, and valve control mechanisms, and their relation one to another as are hereinafter more particularly described in the following specification. The specification is accompanied by drawings in which:

Fig. l is a section taken. in elevation through a tacker embodying features of my invention;

Fig. 5 is an end elevation of the forward bush- Y.

ing, looking in the direction of the arrows 5-5 of Fig. 4;

Fig. 6 is an end elevation of the valve cam and exhaust valve disc, looking in the direction of the arrows 5- of Fig. 4;

Fig. 7 is an end elevation of the inlet valve,

looking in the direction of the arrows 1-1 ofY Fig. 4;

Fig. 8 is an end elevation of the rear bushing, looking in the direction of the arrows 8 8 of Fig. 4;

Fig. 9 is an end elevation of the nipple, looking in the direction of the arrows 9 9 of Fig. 4;

Fig. 10 is a bottom plan View .of a spring r tainer plug. which serves also for adjustment of the travel of the piston;

Fig. 1l is a fragmentary section through the handle at the cam roller;

Fig. 12 shows a staple driven into wood; .and

Fig. 13 is a partially sectioned elevation of a somewhat modified tacker.

Referring to the drawing, and more particularly to Fig. 1, the air operated staple driver comprises a base portion I2, a staple driving blade I 4, a cylinder It, an air operated piston I8 in said cylinder, and means 2&3 connecting the blade to the piston for operation thereby. The device further comprises valve mechanism generally designated 22 for controlling the supply of air from an air hose 2d to the cylinder, and a handle 26 extending over and spaced from the base I2 for handling and holding the staple driver during operation of the same. This handle is at least slightly movable relative to the base and is provided with means 28 whereby pressure on the handle toward the base operates the valve mechanism 22 to cause driving of a staple. The particular device here illustrated is a tacker, and the invention is of greatest advantage when applied to a taclzer, for the handle 2S is then employed to locate the staple and to hold the tacker against the wall or other` surface, whereupon the staple is automatically driven. In the tacker here illustrated the base I 2 is a staple magazine which holds and feeds a bar 3G' of preformed staples to the staple driving blade l. The handle 26 is pivoted on the staple magazine at 32 and is movable toward or away from the magazine about the pivot 32.

It will be observed that the handle 25 is hollow and houses the valve mechanism with its nipple 34. More specifically, the handle 2E has a crosssection in the form of an inverted U and is disposed around the valve housing 22 and nipple 34, these parts preferably being fixedly mounted on the cylinder I6 and preferably extending ge erally collaterally of the staple magazine so that the parts are most readily received within and substantially concealed by the handle. In the particular case here shown the valve housing 22 and nipple 34 extend at a downwardly sloping angle in rearward direction in order to conform to the slope of the handle itself. The top wall of the handle is cut away or omitted near the rear end of the handle, from the point 2l on, leaving only the side walls 36, thus clearing the way for free passage of the air hose 24 leading to the nipple 34,

Considering the drawings in greater detail, and referring first to Fig. l2, the staple 40 may be a conventional staple of inverted U shape, it having legs 42 and 44 connected by a bridge portion 48. Leg 42 may be pointed by cutting the same on a bias, as is indicated at 48, and leg 46 may be cut on a bias in opposite direction, as is indicated at 5e; The staple is shown driven into a wood block or surface 52, and may be employed to secure paper, fabric, or other material to the wood, this beingschematically indicated at 54.

In the present case staples of the specified character are cemented together side by side to form a channel shaped bar of staples. Such a bar of staples is loaded into the staple magazine in any conventional or desired fashion. Some machines are front loading; others are rear loading; and still others are top loading. The present machine may be designed for either front loading or rear loading, and since the specic means for this purposes may be conventional and form no part of the invention, they are not shown in detail. The staples are carried on a staple core 56 within the walls of the magazine housing and are urged forward by a staple pusher 55 which is itself pulled forward by a pull spring 5D extending forwardly and then rearwardly around a pulley to an anchorage 62.

lI'he machine may be-designed for top loading, and in such case it is necessary for the cast frame portion 6E to be openable from the magazine proper, turning upward for example on the pin 32. The frame 64 carries the cylinder I6, which in turn carries the valve housing 22. These parts are all preferably formed as a single cast member. The handle 25 is also preferably cast in desired configuration. The castings may be made of a light metal, such as aluminum or magnesium, thus minimizing the weight of the machine. The remaining parts of the staple magazine may be formed out of heavy gauge sheet metal.

The piston I 8 consists of upper and lower parts between which there is locked a cup-shaped gasket 68. The parts of the piston are held together by a threaded pin e8, the lower end of which carries the staple driver blade I4, the parts being riveted together as shown. In the present case the blade is disposed in the axis of the piston. The cylinder I6 is single acting, and the piston is normally raised by means of a compression spring 1B. The upper end of the spring bears against the piston, and the lower end rests on an adjustable retainer 12. Referring to Fig. 10 the retainer 'I2 is an externally threaded plug or disc having a relatively large aperture 'I4 through which the staple driver blade I4 passes. The retainer has three spanner holes '16, and a fourth hole which is used to secure to the retainer a stud '18.

Revertng to Fig. l, the threaded relation between the retainer and the cylinder holds the retainer in place and supports the compression spring. The retainer may be turned in one direction or the other to adjust the travel of the piston. This adjustment may be made in increments of one-quarter revolution, so that the stud 'I8 may be located between spaced side plates B, thus insuring against possible change of adjustment in the course of use of the machine. The stud is driven into the appropriate one of the four spanner holes.

The valve housing 22 is provided with oppositely faced valve seats 82 and 84. The cylinder I6 is in flow communication with the housing between the Valve seats, as indicated by the passage 86. A valve stem 88 passes through the housing and carries a normally closed inlet disc 90 and a normally open exhaust disc 92. The air pressure serves of itself to normally close the valve disc 9U. It will be understood that movement of the valve stem toward the right serves to close the exhaust valve at the same time that it opens the inlet valve.

The valve disc 90 is substantial in diameter and is preferably made of elastic material. The disc 92 is preferably made of the same material, or at least a compressible material. The reason for this construction will be understood by comparison of Figs. 1, 2 and 3 of the drawing, which show successive stages in the operation of the machine. In Fig. l the inlet valve 9e is closed, the exhaust valve 92 is open, and the piston and driver are raised by the spring lli. In Fig. 2 downward pressure on handle 26 has caused the valve stem 88 to move toward the right. This closes or nearly closes the exhaust disc 92 against the valve seat 82, but has not yet opened the inlet valve. Instead the air pressure holds the edges of the valve disc di) sealed against the valve seat 84, the disc being deformed by the movement at the center of the disc.

Referring now to Fig. 3, continued pressure on handle 26 compresses the exhaust disc 92 and affords slight further movement of valve stem 88 toward the right. The parts are so dimensioned that at this time the restoring forces in the stressed inlet dise 94 overcome the air pressure, and the inlet valve is opened, thus driving the piston I8 downward as indicated, and so causing the staple driver blade I4 to drive the endmost staple of the staple bar 30 downward, as is indicated in broken lines at 30'.

The described operation of the valve mechanism has two main advantages. One is that it permits the exhaust valve to be nearly closed or even actually closed before the inlet valve is opened, thus conserving against wasteful loss of air. The second is that when the inlet valve finally opens it opens abruptly to its maximum widely open condition, and so permits a sudden supply of air which more effectively drives the staple because of its somewhat percussive action.

The construction of the valve mechanism will be better understood by reference to Figs. 4 through 9 of the drawing, in which it will be seen that the exhaust valve disc 92 is carried on the tubular part 94 of a cam member having a conical end 95. A ilange 93 is preferably formed on the cam member to back or support one side of disc 92. The cam member is drilled at IOS to slidably receive the slender valve stem. 88 previously mentioned. This carries a metal fitting |02, which in turn carries the inlet disc 90, said discY being backed or supported on one side by a flange |04.

The two main valve parts are assembled by passing them in opposite directions through the opposite ends of the valve housing 22 previously referred to. The valve parts are then retained in position by screwing appropriate threaded bushings or plugs into the valve housing. The forward plug |06 is threaded at |08, and dimensioned at I I D to slidably receive the cam member 96. The outer end of the bushing |66 has ilats acting as a nut when screwing the bushing into the housing. A sheet metal lockwasher may be disposed inside the head of the bushing, with parts bent in opposite direction, as indicated at I2 in Fig. 1.

The opposite end of the valve housing is closed by concentric bushings II4 and IIS, the latter being formed integrally with the nipple 34. The bushing II4 is both internally and externally threaded and has a head with flats to receive a wrench. rlhe bushing i I6 is externally threaded to iit the internal thread of the bushing IIA. If desi-red the bushings may be combined and made as a single part, that is, the nipple 34 being formed directly on the bushing I4.

The means whereby the handle operates the valve may be understood from inspection of the drawing, but for completeness reference may be made to Fig. 11 showing how a cam roller 28 is freely rotatably mounted on a pin between thickened shoulders |22 on the inside of handle 1 26. The pin I 20' may be riveted or upset slightly at its ends to hold it against axial movement. Reverting now to Figs. l, 2 or Bfthe roller 28 rests on the conically shaped cam surface 9E, so that downward pressure or movement of the handle causes an inward movement of the valve stem.

It will be observed that the valve and handle are devoid of restoring springs. None are needed because the air pressure alone serves to close the valve, and the resulting valve movement functions 4;'

through the cam and roller mechanism to raise the handle. However, springs may be used if desired.

A slightly modified form of the invention is shown in Fig, 13. This construction is generally similar to that already described, except that the staple driving blade |35. is disposed near the forward wall of the air cylinder |32, instead of being disposed coaxially. For this purpose it may be assumed either that the staple magazine |34 has been correspondingly lengthened, or that the cylinder |32 is mounted in a position shifted toward the right relative to the magazine. The fitting |35 to which the blade is riveted is modified, it being offset in forward direction an increased amount, and the spring retainer |38 diiTers from that previously shown in having a large opening |413 for the blade |30 disposed near one side of the disc, it being diametrically opposite the stud |42 which holds the retainer against rotation.

The valve discs may be made of suitable ilexible material. I have found that Neoprene rubber with a hardness of to 80 durometers is very satisfactory. As one specific example, in the particular tacker here illustrated the inlet valve 9|) c is about 19-6" in diameter and M3 in thickness. The diameter of the metal flare on its forward side is and the diameter of metal washer on its rear side is The exhaust valve 92 is about 17s" in diameter and 1/8" in thickness. The

" stem 88.

valve travel is 9/64," of which the last .010 takes care of the sealing of the exhaust valve and the cracking open of the inlet valve. This valve travel is, of course, related to the particular diameter, thickness, and other factors of the inlet valve disc shown and would ordinarily be diierent for a Valve disc of different dimension and character. The critical part of the movement at the end of the valve travel is so small (say .010") that there would be no noticeable loss of air even in the event of incorrect operation such that the inlet valve cracks open simultaneously with or ahead of sealing of the exhaust valve.

The piston gasket may be made of fabric, leather, or neoprene rubber. In all cases Neoprene rubber is preferable to natural rubber bccause of resistance to attack by lubrican. The tacker may be used with air pressures up to 125 lbs., yet will operate satisfactorily with apressure as low as 30 or 40 lbs. Such a pressure is adequate for the staple driving purpose, and will drive a staple with half inch legs into solid wood. The pressure is also adequate to close the air valve and raise the handle, when pressure on the handle is relieved.

The air valve disclosed herein has an addi-y tional advantage in providing safety against operation under excessive pressure. Comparing Figs. 2 and 3, in the event the pressure in the supply line is excessive the resto-ring force within the convexly stressed disc Ell will be inadequate to straighten out the disc, and consequently the valve will not open. In the specic example here shown the safety point is in a range of from to lbs. per square inch. Thus the unit may oe operated in a pressure range of from 30 or 40 lbs. at one end to- 110 or 125 lbs. at the other. This safety against overload is of advantage in protecting the gasket of the piston, and the other working parts of the machine. It is believed that the spread of from 110 to 125 lbs. arises from the fact that the valve disc 9i? is die cut and has somewhat irregular edges, and that by going to the extra trouble and expense of grinding the edges to make the disc perfectly circular, the safety overload pressure may be regulated within far closer limits.

Referring to Fig. 4 the exhaust valve parts S2M I0!! are preferably made freely slidable on the This facilitates assembly, and is believed to have another advantage, namely, in providing a quick action exhaust. Referring to Fig. 3 it will be seen that when the manually applied pressure on the handle 2E is relieved the air pressure against the back of the exhaust valve disc 92 vwill tend to urge it forwardly, and it may move ahead to widely open position. The inlet valve is instantly closed thereafter by the pressure of the air supply in front of the inlet valve, aided by the sudden reduction in pressure behind the inlet valve resulting from opening of the exhaust valve. The whole action is so fast that there is no appreciable escape of air from the inlet pipe. rlhe piston rises instantly. However, the loose, sliding fit between the exhaust and inlet parts of the valve is not at all essential, and a tight t may be provided if desired.

The reason for the use of the two pieces I and II@ at the hose inlet 34 is as follows: The outside thread on the bushing Ile is a straight thread and is received in the relatively soft aluminum metal of the valve housing. The thread on the inside of the bushing Ilbl is preferably a tapered or pipe thread and receives a similar mating pipe thread on the outside of the nipple part H6. The parts H4 and IIB are both made of brass, and the thread therebetween is better able to withstand wear than would aluminum. In changing hoses, as, for example, from a short hose to a long hose, the change is preferably made by unscrewing the nipple part liE with its hose from the bushing H4, and then connecting another hose with its own nipple part IIB to the bushing H4. A further advantage of using the two pieces H4 and IIB instead of a single piece, is that the bushing H4 serves to hold the inlet valve against escape from the valve housing when the nipple part H5 is removed.

In respect to the pivoting of the handle 26 it will be noted that the manual pressure is applied close to the valve operating end of the handle, and what is additionally and perhaps even more important, the manual pressure is applied close to the staple driving blade, and thus is better able to take the reaction of the staple driving below.

It is believed that the construction and operation of my improved air operated tacker, as well as the advantages thereof, will be apparent from the foregoing detailed description. It will also be apparent that While I have shown and described the invention in a preferred form, changes may be made in the structure disclosed without departing from the scope of the invention as defined in the following claims.

The features of the quick-acting valve disclosed herein are not claimed in the present application, and instead are claimed in a copending continuation-impart application, Serial No. 364,139, led June 25, i953, and entitled Air Valve.

I claim:

1. An air-operated stapling machine comprising a base portion, a staple driving blade, a cylinder, an air-operated piston in said cylinder, means connecting the blade to the piston for operation thereby to drive a staple, valve mechanism for controlling the supply of air to said cylinder, a handle extending over and spaced from said base for handling and holding said machine during operation of the same, said handle being movable relative to said base, and means operative between said handle and said valve mechanism whereby pressure on said handle toward said base operetes the valve mechanism to cause driving of a staple.

2. An air-operated stapling machine comprising a staple magazine for holding and feeding a bar of preformed staples to a staple driving blade, a cylinder, an air-operated piston in said cylinder, means connecting the blade to the piston for operation therebyT to drive a staple, valve mechanism for controlling the supply of air to said cylinder, a handle extending over and spaced from said magazine for handling and holding said lriver during operation of the same, said handle being movable relative to said magazine, and means operative between said handle and said valve mechanism whereby pressure on said handle toward said magazine operates the valve mechanism to cause driving of a staple.

3. An air-operated tacker comprising a staple magazine for holding and feeding a bar of preformed staples to a staple driving blade, a cylinder, an air-operated piston in said cylinder, means connecting the blade to the piston for operation thereby to drive a staple, valve mechanism for controlling the supply of air to said cylinder, a handle extending over and spaced from said magazine for handling and holding said tacker during operation of the same, said handle being pivoted on said magazine, and means operative between said handle and said valve mechanism whereby pressure on said handle toward said magazine operates the valve mechanism to cause driving of a staple.

4. An air-operated stapling machine comprising a base portion, a staple driving blade, a cylinder disposed over said base, an air-operated piston in said cylinder, means connecting the upper end of the blade to the piston for operation thereby to drive a staple, a hollow handle extending over said base from the rear end of the base to the upper end of the cylinder, and valve mechanism including a valve housing and an air hose nipple located in the hollow space in said handle, the top of said handle being open near the rear end of the handle for passage of an air hose to the aforesaid nipple.

5. An air-operated stapling machine comprising a staple magazine for holding and feeding a bar of preformed staples to a staple dlriving blade, an upright cylinder disposed over the forward end of said magazine, an air-operated piston in said cylinder, means connecting the upper end of the blade to the piston for operation thereby to drive a staple, a hollow handle extending over said magazine from the rear end of the magazine to the upper end of the cylinder, and valve mechanism including a valve housing and an air hose nipple housed in the hollow space within the aforesaid handle, the top of said handle being open near the rear end of the handle for passage of an air hose to the aforesaid nipple.

6. An air-operated tacker comprising a staple magazine for holding and feeding a bar of preformed staples to a staple driving blade, an upright cylinder disposed over the forward end of said magazine, an air-operated piston in said cylinder, means connecting the upper end of the blade to the piston for operation thereby, a handle of inverted U section extending over said magazine from the rear end of the magazine to the upper end of the cylinder, valve mechanism including a valve housing, a valve stem, and an air hose nipple all housed within the aforesaid handle, with the valve housing stem and nipple extending collaterally of the magazine and at a downwardly sloping angle in rearward direction in order to conform to the slope of the handle, the top of said handle being open near the rear end of the handle for passage of an air hose 'to the aforesaid nipple.

7. An air-operated stapling machine comprising a base portion, a staple driving blade, a cylinder mounted over said base, an air-operated piston in said cylinder, means connecting the blade to the piston for operation thereby to drive a staple, valve mechanism for controlling the supply of air to said cylinder and including a valve housing with an air hose nipple carried by the cylinder, a hollow handle extending over said base, said handle housing the aforesaid valve mechanism and being movable relative to said magazine, and means operative between said handle and said valve mechanism whereby pressure on said handle toward said magazine operates the valve mechanism to cause driving of a staple.

8. An air-operated stapling machine comprising a staple magazine for holding and feeding a bar of preformed staples to a staple driving blade, an upright cylinder mounted over the forward end of said magazine, an air-operated piston in said cylinder, means connecting the upper end of the blade to the piston for operation thereby to drive a staple, valve mechanism for controlling the supply of air to said cylinder and including a valve housing with an air hose nipple carried by the upper end of the cylinder, a hollow handle extending over said magazine from the rear end of the magazine to a point over the cylinder, said handle housing the aforesaid valve mechanism and nipple, said handle being movable relative to said magazine, and means operative between said handle and said valve mechanism whereby movement of said handle toward said magazine operates the valve mechanism to cause driving of a staple, said handle being open for passage of an air hose to the aforesaid nipple.

9. An air-operated tacker comprising a staple magazine for holding and feeding a bar of preformed staples to a staple driving blade, an upright cylinder mounted over the forward end 'of said magazine, an air-operated piston in said cylinder, means connecting the upper end of the blade to the piston for operation thereby, valve mechanism for controlling the supply of air to said cylinder and including a valve housing, and a rearwardly pointed air hose nipple all carried by the upper end of the cylinder and extending collaterally of the magazine, a handle of inverted U section extendingover said magazine from the rear end of the magazine to a point over the cylinder, said handle enclosing the aforesaid valve mechanism and nipple, the rear end of said handle being pvoted on said magazine, and means operative between said handle and said valve mechanism whereby pressure on said handle toward said magazine operates the valve mechanism to cause driving of a staple,

10 said handle being open near its rear end for passage of an air hose to the aforesaid nipple.

10. An air-operated stapling machine comprising a staple magazine for holding and feeding a bar of preformed staples to a staple driving blade, an upright cylinder mounted over the forward end of said magazine, an air-operated piston in said cylinder, means connecting the upper end of the blade to the piston for operation thereby, valve mechanism for controlling the supply of air to said cylinder and including a valve housing with a valve stem and with a rearwardly pointed air hose nipple carried by the upper end of the cylinder and extending collaterally of the magazine, a hollow handle extending over said magazine from the rear end of the magazine to a point over the cylinder, said handle housing the aforesaid valve mechanism and nipple, the forward end of said valve stem having a downwardly sloping cam surface, the inside of said handle at its forward end having a cam roller resting on said cam surface, and the rear end of said handle being pivoted onthe rear end of the magazine, whereby pressure on the handle operates the valve to cause driving of a staple.

References Cited in the flle of this patent UNITED STATES PATENTS

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