US3278103A - Fastener applying device - Google Patents

Description

4 Sheets-Sheet 1 G. c. JUILFS ETAL FASTENER APPLYING DEVICE Oct. 11, 1966 Filed April 6, 1965 INVENTORS Gsoms C.Jum=s FRANK W. PueH AND CARL 17 Beam, W1, mjmw +51% ATTORNEYS United States Patent 3,278,103 FASTENER APPLYING DEVICE George C. Juilfs, Frank W. Pugh, and Carl T. Becht, all of Cincinnati, Ohio, assignors to Senco Products, Inc., Cincinnati, Ohio, a corporation of Ohio Filed Apr. 6, 1965, Ser. No. 445,873 28 Claims. (Cl. 227130) This is a continuation-in-part application of our copending application Serial No. 372,763 which was filed June 5, 1964 and entitled Fastener Applying Device, now abondoned.

This invention relates to fastener applying devices, and particularly to pneumatic stapling and nailing tools. More specifically, this invention rel-ates to such a device which may be actuated to deliver a rapid sequence of operative cycles, each cycle driving a fastener.

In conventional pneumatic fastener applying devices, compressed air from a suitable source of supply is admitted into a working cylinder to drive a piston or working member and its associated driver in a working cycle including a driving stroke and a return stroke. A plurality of fasteners from a magazine or other source of supply are successively fed into a drive track in a position to be driven by the fastener driver on its working stroke. Control of the admission of air into the working cylinder of the tool is achieved by a suitable pneumatic firing valve, which in turn may be controlled by a manually actuated trigger. The manually actuated trigger may be combined with a combination safety and workpiece responsive trigger in the manner taught in copending application Serial No. 489,142, entitled Firing Control Means in the names of G. C. Juilfs and F. W. Pugh, and filed September 22, 1965.

In all of these prior art devices, the maximum speed of operation of the tool is controlled and in some cases limited by the operators manual dexterity. In some cases, especially where the operator must re-arrange the workpiece between successive fastener driving operations, such limitation has no real effect. However, in many applications it would be desirable to provide a fastener applying device which would drive a plurality of fasteners faster than even a skilled operator could actuate the trigger. For example, in constructing a crate, the operator may wish to fasten two boards together with three staples and does not particularly care where these staples are located within a given area. Or perhaps a piece of material is to be fastened to a long board. In these cases, it would be desirable for the operator to pull the trigger once and hold it in a depressed position while the tool rapidly drives the desired number of fasteners. The operator then need only move the tool with respect to the workpiece to accomplish the particular operation in question.

It is, therefore, a primary object of this invention to provide a pneumatic fastener applying device which, upon a single actuation of a trigger member, will continuously carry out its normal working cycle until the trigger member is released. In this connection, it may be noted that there are a number of pneumatically actuated devices which will continuously cycle upon actuation of a trigger member, such as, for example, the pneumatic hammers and riveters. However, it must be emphasized that in the case of pneumatic fastener applying devices, the working piston must drive a fastener on each working stroke. This makes it necessary for the piston and its associated fastener driver to make a full return stroke during each operative cycle. This is not true of the operation of the conventional repetitive cycling pneumatic tools.

One embodiment of a continuously cycling pneumatic fastener applying device has been disclosed in the copending application, Serial No. 368,855, entitled Method 3,278,103 Patented Oct. 11, 1966 "ice and Apparatus for Increasing the Numbers of Strokes Performed by Pneumatic Piston-Cylinder Devices in a Given Period of Time, in the name of Carl Siegmann, and filed May 20, 1964.

More specifically, it is an object of this invention to provide a pneumatic fastener applying device which will insure a full return stroke of the working piston in each operative cycle, thereby providing a full power stroke and insuring that a fastener will be fed into position to be driven after each return stroke.

A further object of the invention is to provide a fastener applying device which may selectively be operated as a conventional single fire tool, or may be made to continuously cycle as an auto-fire tool.

Still another object of the invention is to provide a single threeposition trigger by means of which the operator may control at his option the mode of operation of the tool.

Still a further object of the invention is the provision of a trigger as described above in combination with a safety.

Another object of this invention is to provide as an alternative to the three-position trigger, a positive off-on switch by means of which the mode of operation, i.e., auto-fire or single fire of the tool, may be controlled.

A further object of the invention is to provide means by which the operator may control the speed at which the tool, in its auto-fire mode of operation, cycles.

Numerous other objects and advantages of this invention will become apparent to the skilled worker in the art upon reading this specification in conjunction with the accompanying drawings, in which:

FIGURE 1 is a side elevational view with parts broken away and parts in section showing a pneumatic fastener applying device according to this invention;

FIGURE 2 is a cross-sectional view showing a portion of the elements shown in FIGURE 1, showing the parts in the position attained upon actuation of the safety only;

FIGURE 3 is a cross-sectional view similar to FIGURE 2 showing the relation of the parts when the tool is to be operated in its single fire mode of operation;

FIGURE 4 is a cross-sectional view similar to FIG- URES 2 and 3 showing the relation of the parts when the tool is to be operated in its auto-fire mode of operation;

FIGURE 5 is a cross-sectional view on a greatly enlarged scale showing the selective control means according to this invention;

FIGURE 6 is a cross-sectional view showing a modification of the invention arranged for single fire operation; and

FIGURE 7 is a cross-sectional view showing the modification of FIGURE 6 arranged for auto-fire operation.

Briefly considered, the invention contemplates the usual fastener applying tool elements including a working cylinder and piston, a drive track, a fastener driver associated with the Working. piston and reciprocable in the drive track, and means for successively feeding a plurality of fasteners into the drive track in a position to be driven by the fastener driver.

Admission of pneumatic power to the working cylinder may be controlled by a suitable pneumatically operated firing valve which is in turn (in one embodiment of the invention) controlled by the selective control valve of this invention. This selective control valve is actuated by a manual trigger, this trigger being movable from an inoperative position to a single fire position, at which point the operator encounters a noticeable resistance, and wherein the tool operates in a conventional single fire manner.

By the exertion of continued force on the trigger, the operator is able to overcome the resistance, and the trigger moves to an auto-fire position, wherein the tool cycles repetitively, a fastener being fed into the drive track after each return stroke, and each driving stroke being effective to drive a fastener into a workpiece.

In another embodiment of the invention, the change from single fire to auto-fire is accomplished by means including a novel off-on switch arrangement.

Brief description of firing valve and piston return Referring now particularly to FIGURE 1, the fastener applying device of this invention includes the housing having a body portion 10 and handle portion 12 forming a reservoir 14 for the storage of air under pressure. The top of the body portion 10 is closed by the cap 16 having the downwardly projecting central post having the portion 18 of a given diameter and the portion 19 of a reduced diameter. The cap 16 may be secured to the body portion 10 in any suitable manner and is sealed thereto with the O-ring 20 (the phrase O-ring is used simply as exemplary of any conventional, resilient sealing means) to prevent the loss of compressed fluid.

Slidably received about the post 18, 19 and within the body portion 10 is the firing valve piston 22, which is sealed against the body portion by means of the O-ring 24 and against the portion 18 of the post by the O-ring 26. The lower portion of the firing valve piston 22 is provided with the annular resilient valve member 28, which is adapted to seat against the firing valve seat 30. The firing valve seat 30 is secured to the lowermost edge of the portion 19 of the post as will be described in more detail hereinafter.

The portion 19 of the post is provided with the exhaust valve washer 32 which is held in place between the firing valve seat 30 and the shoulder between the portions 18 and 19 of the post by means of the spacer collar 34 and the spring clip 36.

Received within and spaced from the walls of the body portion 10 is the sleeve or linear 38, forming the working cylinder for the tool. The sleeve 38 carries at its upper end the xO-ring 40 which effects a seal between its upper surface and the firing valve seat 30. About the lower portion of the sleeve 38 is the O-ring 42 which effects a seal between the outer surface of the sleeve 38 and the inner surface of the body portion 10, thereby forming and maintaining two distinct air reservoirs 14 and 56.

Slidable within the sleeve 38 is the working piston 44 provided with the annular groove containing the O-ring 46 maintaining a seal between the edge of the piston and the walls of the working cylinder. Secured to the lower surface of the piston 44 in any conventional manner is the fastener driver 47 which is ,reciprocable in the drive track 48 in the nose piece of the tool.

At the bottom of the working cylinder is provided the resilient piston stop 50, which defines the lowermost position of the piston at the end of its'working stroke. Spaced above the top surface of the stop 50 are a plurality of ports 52 in the sleeve 38. These ports 52 open into an annular groove in the sleeve 38 which carries the resilient valve means 54, forming in effect a one-way valve communicating betwen the interior of the working cylinder and the air return reservoir 56 when the piston 44 is in its lowermost position.

Located behind the drive track 48 in the nose piece of the tool is the fastener feed magazine indicated generally at 58. Thisincludes the fastener follower 60 and spring 62 which serves to normally urge a plurality of fasteners 64 into the drive track 48.

The operation of the foregoing elements is in accordance with the teachings of US. Patent No. 3,170,487

entitled Springless Firing Valve, and US. Patent No.

2,983,922 entitled Portable Stapler with Pneumatic Drive and Return, and will now be reviewed generally. In the position shown in FIGURE 1, compressed air at equal pressure will be acting upon the upper surface 22a and the lower surface 22b of the firing valve position 22. Because of the greater effective area of the surface 22a, the resultant force will be downwardly, and the piston 22 and resilient valve member 28 will be forced downwardly against the firing valve seat 30. Actuation of the trigger, through means described in more detail hereinafter, will exhaust the compressed air acting on the surface 22a, and the compressed air acting on the surface 22b becomes sufficient to force the firing valve piston 22 to its uppermost position shown in FIGURE 3, wherein the valve member 28 is lifted off of the firing valve seat 30 and compressed air is admitting to the working cylinder. It will be noted that in this uppermost position of the firing valve piston 22, the O-ring 64 carried near the lower end of its bore is in engagement with the exhaust valve washer 32, thereby preventing .the escape of compressed air through the exhaust passages 66 and 68.

The compressed air then drives the working piston 44 downwardly, driving a fastener through the drive track 48 into a workpiece.

When the piston 44 is in its lowermost position, compressed air passes through the ports 52 into the air return reservoir 56. The components will remain in this position until the operator releases the trigger.

Upon release of the trigger, compressed air is once again introduced to the surface 22a on top of the firing valve piston 22. Due to its greater effective area, that is, greater than the effective area of the underside of the piston 22, which underside is considered as made up of the surface 220, the underside of the member 28 and the effective surface 22b, the piston is once again forced to its down or closed position. As seen in FIG- URE 1, this brings the O-ring 64 out of engagement with the exhaust Washer 32, permitting air in the working cylinder to exhaust around the washer 32 and to atmosphere through the passages 66 and 68. Compressed air passed into the air return chamber 56 then acts on the underside of the working piston through the ports 70 and the relieved portion 72 of the piston stop 50, to force the piston 44 to its uppermost position so that the cycle may be repeated.

Selective control means An important phase of this invention resides in the provision of a control means, whereby the tool may selectively be operated in a single fire or an autofire mode of operation.

The preferred selective control means of this invention is shown on a greatly enlarged scale in FIGURE 5 and includes the four tubular, stacked sections 74, 76, 78 and 80. Within the section 74 are the trigger responsive actuating member 82 and the workpiece responsive actuating member 84 which include, respectively, the rods 86 and 88 extending through the base of the lower section where they may be moved by the triggers described hereinafter. The actuating memhers 82 and 84 are both normally biased to the lowermost position shown in FIGURES 1 and 5 by means of the resilient means 90.

The second section 76 of the selective control means extends into .the lower section 74, and is sealed therewith by means of the O-ring 92. The lowermost portion of the section 76 is provided with a bore in which is slidably mounted the resistance contacting sleeve 94. The upper portion of the bore in the section 76 is enlarged to receive the member 96 which carries the resistance creating washer 98. The member 96 is sealed within the bore of section 76 by means .of O-ring 100. Also in the enlarged bore of the section 76 and beneath the member 96 is the cup-shaped washer 182.

Section 78 of the selective control means is provided with the annularly spaced ports 184 which communicate with the air storage reservoir 14 in the handle of the fastener applying device.

Section 80 of the selective control means is provided with the annular relieved portion 186 and the ports 188 which communicate between the relieved portion 105 and the bore of section 81 The relieved portion 106 communicates via the passage 187 with the space above the firing valve piston 22. Near its upper end, section 88 includes the relieved portion 118 and ports 112 which provide communication between the bore of section 80 and atmosphere through the passage 114. The four sections 74, 76, 78 and 81) are assembled as shown, placed in the housing of the tool, and held in place by means of the cap 16 and O-ring 115.

Extending through the four sections described above is the valve member 116, which is shaped as shown in the drawings, and provided with the O- rings 117, 118, 119, 120, 121, 122 and 123. The co-action of these O-rings and the sections of the selective control means described above will be explained in detail very shortly.

As noted before, the rods 86 and 88 associated respectively with the actuating members 82 and 84 extend through the bottom of the lowermost section 74 of the selective control means. In the preferred embodiment of the invention, the rod 86 is contacted and moved by the manual trigger 124, (FIGURE 4), and the rod 88 is adapted to be contacted and moved by the touch fire trigger 126 (FIGURE 4). As explained in the copending application entitled Firing Control Means noted above, the touch fire trigger 126 is mechanically associated with the touch fire control member 127 (FIGURE 1), surrounding the nose piece of the tool, so that simply placing the tool itself closely adjacent the workpiece will actuate the touch fire trigger.

As best seen in FIGURE 5, the actuating members 82 and 84 are formed into cam surfaces having the bypass portions 8211 and 84a, and the relieved portions 82b and 84b respectively. The shoulders 82c and 840 respectively, join the by-pass and relieved portions. These cam surfaces coact with the firing element 128 to control movement of the valve element 116, and hence the cycling of the tool.

Starting from the position seen in FIGURES 1 and 5, the actuating members 82 and 84 are both in their lowermost positions, and the firing element 128 is resting on the shoulders 82c and 840. Upon movement of either the rod 86 or rod 88 and its associated actuating member 82 or 84 respectively, the firing element 128 will move laterally to a position between the by-pass portion of the unmoved actuating member and the relieved portion of the moved actuating member. It should also be noted at this time that compressed air from the storage chamber 14 enters the ports 184, and bears on the surface 138 of the valve element 116, normally urging this element downwardly. This downward bias prevents an accidental movement of the valve element 116 during movement of only one of the actuating members 82 and 84.

The operation of the selective control valve described above may be briefly outlined as follows. The valve member 116, which controls the actuation of the firing valve, is movable from an inoperative position to a single fire position, and to an auto fire position. Movement of the valve member 116 is controlled by the firing element 128, which is also movable to three positions, corresponding directly to the positions of the valve member 116. Movement of the firing element 128 is controlled by the two separate and independent actuating members 82 and 84. The member 82 (responsive to the manual trigger) is movable to three positions, again, an inoperative position, a single fire position, and an auto fire position, while the workpiece responsive actuating member 84 is movable to only two positions, an inoperative position and an operative position. For the tool to fire at all, both of the actuating members must be moved from their respective inoperative positions. In other words, if either of the actuating members is in its inoperative position, the tool will not fire; each therefore acts as a safety for the other. More specifically, if the workpiece responsive actuating member is moved to its operative position and the trigger responsive actuating member is moved to its single fire position, the firing element 128 and valve member 116 are thereby both moved to their single fire positions; movement of the workpiece responsive actuating member to the same operative position, and concurrent movement of the trigger responsive actuating member .to the auto fire position, will effect movement of the firing element and valve member to their auto fire positions.

By virtue of this arrangement, selection of the mode of operation (i.e. single fire or auto fire) is accomplished entirely by the manual trigger. But the actual initiation of firing may be accomplished by either actuating memher. For example, the operator can pre-select the mode of operation by means of the manual trigger, and the tool will not fire until the workpiece responsive actuating member has been actuated, or vice versa.

Again starting with the components in the position shown in FIGURE 1, the operation of the selective control valve will now be described. Assuming that the tool has been placed adjacent a workpiece, the workpiece responsive actuating member 84 will be moved upwardly to its operative position shown in FIGURE 2. The member 84 is relieved as at 132 (shown clearly in FIGURE 5), so that during its upward movement, it will pass the resistance contacting sleeve 94 with clearance. The firing element 128 has moved laterally to a position disposed between the by-pass portion 82a and the relieved portion 84b of the actuating members.

If the workpiece responsive actuating member 84 is maintained in the operative position, and the operator now exerts pressure on the manual trigger 124, the rod 86 and actuating member 82 will be moved upwardly. The firing element 128 is prevented from further lateral movement by the relieved portion 84b, and hence will be moved upwardly by the shoulder 820 of the actuating member 82 as seen in FIGURE 3. This will bring the firing element 128 into contact with the stem of the valve element 116 moving it upwardly. This will bring the O-ring 120 on the valve element 116 into contact with the bore of section 80 of the selective control means,

thereby cutting off the supply of compressed air to the space above the firing valve piston 22 around the O-ring 120, through the port 188, relieved portion 186 and passageway 107. Shortly after initial contact between the O-ring and the bore of the section 80, the O-ring 121 will move into the relieved portion 134 of section 80, permitting the air above the firing valve piston 22 to exhaust through the passage 107, the relieved portion 186, the ports 188, past the O-ring 121, through the relieved area 134, out the ports 112, the relieved portion 118, and to atmosphere via the exhaust passage 114. This reduction in pressure applied to the surface 22a of the firing valve piston permits the compressed air in the storage reservoir 14 and acting on the surface 22b of the firing valve piston to open the valve, admitting compressed air into the working cylinder of the tool and driving the working piston to its lowermost position as earlier described. When either the manual trigger 124 or the touch first trigger 126 is returned to its inoperative position, its associated actuating member will return to the inoperative position, permitting the firing element 128 and valve member 116 to be returned by air acting on the surface 130 of the valve member to their inoperative positions. This action re-adrnits air from the reservoir 14 to the space above the firing valve piston 22, causing it to close in the manner previously described. FIGURE 3, therefore, represents the single fire position for the various elements.

It will also be noted in FIGURES 5 and 3 that the actuating member 82 contacts and moves upwardly the resistance contacting sleeve 94. As further shown in FIGURE 5, there is a clearance space between the top of the sleeve 94 and the bottom of the cup shaped washer 102. Therefore, upward movement of the manual trigger 124 will proceed at a relatively constant pressure, until the components reach the single fir-e position shown in FIGURE 3, at which time the sleeve 84 has contacted the cup washer 102 and raised this against the member 96 and resistance creating washer 98. At this point, the operator will feel a definite and increased resistance, due to air under pressure entering the port 136 and tending to force the resistance creating washer 98 and member 96 downwardly.

It will be noted that by virtue of the construction taught herein, the increased resistance may be overcome and virtually relieved if the operator proceeds to pull the trigger to the auto fire position. That is, once the operator, by continued pressure on the manual trigger 124 overcomes the resistance and actuates the member 96 and washer 98, air pressure entering the port 136 will be applied to both surfaces of the washer 98, and the additional resistance will be virtually eliminated. Therefore the operator, upon pulling the trigger, will immediately be able to tell when he reaches the resistance point in trigger pull between the single fire and auto fire modes of operation, but can operate the tool in its auto fire mode of operation without fatigue.

FIGURE 4 shows the manual trigger 124 and actuating member 82 after having been moved past the single-fire position, and into the auto fire or uppermost position. In this position, the space above the firing valve piston 22 has been cut off from the supply of compressed air in the reservoir 14 by the O-ring 128, and is cut ofif from the normal exhaust passage by the O-ring 122. At this time, the uppermost end 168 of the valve member 116 has contacted the pivotal valve 164, moving it from the closed position shown in FIGURES 1 through 3 to the open position shown in FIGURE 4.

Auto fire valve Turning again to FIGURE 1, it will 'be seen that disposed centrally of the depending post 18, 19, is the auto fire valve housing 138, which is held in the cap 16 by the top 140, and sealed in these two members by the O-rings 142 and 144. Slidarbly disposed within the housing 138 is the valve actuator 146, with its bottom portion cut away as at 148 and including the slots 158 opening into the relieved space 152 within the housing 138. Secured to the top of the actuator 146 is the resilient valve 154 which, in the lowermost position shown in FIGURE 3, seats on the internal shoulder within the housing 138. The valve actuator 146 and the resilient valve 154 are normally urged downwardly by the spring 156.

The top of the Valve housing 138 communicates with the passage 158 formed in the top 140. The passage 158 intersects the formed passage 160 which receives the speed control valve 162. The right hand end of the passage 160, as viewed in FIGURE 1, is closed by the pivotal valve 164, which is normally urged to the closed position shown in FIGURES 1 and 2, by the spring 166.

The auto fire mode of operation will now be described, starting with the parts in the position shown in FIGURE 2; that is, with the touch fire trigger 126 having been actuated and the rod 88 and actuating member 84 being raised to the uppermost position and the manual trigger 124 in the inoperative position. As described above, upward movement of the manual trigger 124, through the rod 86 and actuating member 82, will cause the firing element 128, the valve member 116, resistance contacting sleeve 94 and cup-shaped washer 182 to move upwardly, bringing the parts to the position shown in FIGURE 3 (the single fire position). At this time, the operator will encounter a definite resistance against the continued pull of the trigger, and the first half or working stroke of an operating cycle of the tool will be performed.

When the operator overcomes the resistance created by the washer 98, and continues to move the trigger 124 upwardly, the rod 86, actuating member 82, and valve memher 116 will continue to move upwardly, bringing the parts into the position shown in FIGURE 4 (the auto fire position). At this time, the O-ring 121 will remain in the relieved portion 134 of the section of the selective control means, while the O-ring 122 will have moved out of the relieved portion 134 and into engagement with the upper portion of the bore in section 88, immediately below ports 112. This serves to cut the space above the firing valve piston 22 off from its normal exhaust passage to atmosphere. At the same time, the uppermost end 168 of the valve member 116 will contact the pivotal valve 164, moving it from the position shown in FIG- URES 1 through 3, to the position shown in FIGURE 4. At this time, bear in mind, the working piston is at its lowermost position, and the working cylinder will be filled wit-h compressed air. This compressed air will act upwardly, through the stern of the auto fire valve actuator 146, overcoming the spring 156 and lifting the valve 154 off its seat, and permitting compressed air to pass through the ports 158, around the valve 154, through the passages 158 and 160, past the now open valve 164, and through the passage 178 in the cap 16, into the space above the firing valve piston 22. It will be recalled that by virtue of the construction generally described above and set forth in more detail in the said US. Patent No. 3,170,487 entitled Springless Firing Valve, the upper surface 22a of the firing valve 22 has a greater effective area than its lower surface 22b, 22c and 28. Therefore, as compressed air following the path outlined above increases the pressure on the surface 22a, the firing valve 22 will be forced downwardly to its closed position.

As stated before, when the firing valve 22 reaches the closed position, the exhaust valve washer 32 comes out of contact with the O-ring 64, permitting the escape of compressed air in the working cylinder, through the exhaust passages 66 and 68 to atmosphere. This escape of compressed air results in the valve 154 being closed by its spring 156.

With the working piston 44 in its lowermost position, and with the air pressure acting on its top side vented, compressed air in the air return reservoir 56 may then act on the under side of the piston through the ports 70 and relieved portion 72 of the piston stop 50, to force the piston 44 to its uppermost position.

When the piston reaches its uppermost position at the end of its return stroke, the top of the piston 44 contacts the auto fire actuator 146, and moves it and the valve 154 upwardly, thereby now permitting the compressed air above the firing valve piston 22 to escape through the passage 170, past the valve 164, the passage 168, the passage 158, past the valve 154, the relieved portion 152, the ports 158, the cut-away portion 148, the relieved portion 172 in the top of the piston 44, through the firing valve seat 30, around the exhaust valve washer 32, and through the passages 66 and 68 to atmosphere. As the pressure acting on the surface 22a of the firing valve piston is reduced, air acting on the surface 22b forces the valve open, and the cycle repeats itself.

To briefly review the auto fire mode of operation, the compressed air above the top of the firing valve piston 22 is initially exhausted through its normal exhaust passage 107, 106, 188, 134, 112, and 114, thus permitting the compressed air acting on the under side of the firing valve piston to raise this piston and open the firing valve. Compressed air then enters the working cylinder, forcing the piston 44 downwardly and driving the fastener into a workpiece. By this time, continued movement of the manual trigger and selective control valve 116 has blocked oh the normal exhaust passages 107, 106, 188, 134, 112, 118 and 114 for the space above the firing valve piston 22 and has opened the valve 164. Compressed air in the working cylinder above the working piston 44 forces open the auto firing valve 146, 154 and passes into the space above the firing valve piston, thereby closing and re-seating the firing valve piston 22, thus permitting the air above the working piston 44 to exhaust around 32 and through 66 and 68, the working piston to be returned to its starting position by the air within 56, and the spring biased auto fire valve 146, 154 to close. At substantially the end of its return stroke, however, the Working piston 44 reopens the auto fire valve 146, 154, thereby now permitting the air trapped above the firing valve piston 22 to escape to atmosphere through what for it is an auxiliary exhaust path, namely, through the auto fire valve 146, 154 and out the exhaust passages 66 and 68 from the working cylinder via the clearance 172 in the piston 44. When the pressure acting on the top surface of the firing valve piston has been reduced sufiiciently, compressed air in the main storage chamber will open the firing valve and the cycle will repeat.

Once again, it should be emphasized at this time that in the auto fire mode of operation, the bleeding off of air above the firing valve piston (which serves to open this valve) cannot begin until the working piston has completed a substantially full return stroke. This is insured because the auto fire valve cannot open until the top of the piston contacts the auto fire valve actuator 146. As set out earlier in this specification, this insures that a fastener will be fed into the drive track in a position to be driven after each return stroke, and will thus insure that each working stroke of the piston serves to drive a fastener.

The cycling speed of the tool depends on the rate of flow of air through the auto fire valve 146, 154. That is, during the working stroke of the piston 44, compressed air from the working cylinder passes through the auto fire valve and passages 158, 160, and 170 into the space above the firing valve piston 22, and the firing valve piston 22 will not close until sufiicient pressure has been built up in this space to overcome the air pressure acting on the surface 22b of the piston. Furthermore, the re-opening of the firing valve piston will depend on the time elapsing between opening the auto fire valve when the piston 44 reaches the top of its return stroke, and the time when the pressure acting on the surface 22:: of the firing valve piston has been reduced sulficiently by exhausting through the passages 170, 160, and 158, the auto fire valve, and the exhaust passages 66 and 68 from the working cylinder, to permit the firing valve piston to be opened by air in the reservoir 14 acting on the surface 221:.

Control over cycling speed is achieved by means of the speed control valve 162 which is threaded into the passage 160, and may be adjusted by turning the knob 174, to vary the rate at which air enters the space above the firing valve piston during the working stroke, and the rate at which it escapes therefrom after the return stroke. The speed control valve 162 is provided with the cylindrical extension 163, to limit the maximum opening through the passage 160, to prevent premature closing of the firing valve during the working stroke of the piston 44.

A modification f the invention A modified form of the invention is shown in FIG- URES 6 and 7. Briefly considered, this modification replaces the three position trigger selective control valve of the preferred embodiment with a conventional two position trigger (an inoperative position and an operative position) and a positive off-on control or mode selector valve by means of which the operator is able to select the single fire or auto fire mode of operation. The firing valve and auto fire valve of this modification are substantially the same as those described in connection with the preferred embodiment, and similar reference numerals will be used to denote corresponding parts.

As indicated above, the three position selective control means of the preferred embodiment of the invention has been replaced in this modification by the more conventional two position remote control valve. This includes the valve stem 200 having the portion 201 of reduced diameter, and the O- rings 202 and 203 seated .in suitable grooves. The lower portion 200a of the valve stem is of an enlarged diameter, and is sealed within the housing as at 20%. The upper portion of valve stem 200 is slidable within the sleeve 204 which is mounted in the housing as shown, and is held in place by the cap of the tool. The exterior surface of the sleeve 204 is provided with the relieved portion 205 and the O-ring 206 near its upper edge which effects a seal with the housing. The internal surface of the sleeve 204 is provided with the recesses 207 and 208 at its upper and lower ends respectively. The valve sleeve also is provided with .a plurality of radial passages 209 efiecting communication between the relieved area 205 and the hollow center of the sleeve 204.

It will be understood that the valve member 200 is adapted to be moved by any desired trigger means. That is, the member 200 can be made responsive to the actuating members 82 and 84, as described above, or can be directly controlled by a suitable trigger.

In the lowermost or inoperative position shown in FIGURE 6, compressed air in the handle reservoir 14 passes into the recess 208, pass the O-ring 202, into the relieved space created by the reduced diameter portion 201 of the valve stem 200, through the passage 209, through the relieved portion 205, into the passage 107, and into the space above the top surface 22a of the firing valve piston. As explained earlier, the greater effective surface area 22a of this piston forces it to the down or closed position wherein the resilient valve member 28 is seated on the firing valve seat 30. It should also be noted that compressed air in the chamber 14 acts on the enlarged portion 200a of the valve stem to normally bias it toward this inoperation position.

The mode selector control of this modification is mounted in the cap 16, and includes the two-part valve cage 210a, 21Gb (hereinafter referred to generally as valve cage 210), the mode selector sleeve 211 slidably received therein, and the formed speed control 212. The external surface of the valve cage 210 is provided with the relieved portions of smaller diameter 213, 214, and 215. These various relieved portions are sealed one from the other by the O- rings 216, 217, 218 and 219.

The internal surface of the valve cage 210 is enlarged or relieved as at 220 and 221, for purposes described hereinafter.

The hollow, slidable mode selector sleeve 211 carries on its outer surface in appropriate grooves the O- rings 222, 223, 224 and 225 which, as described hereinafter, effect a seal with certain portions of the interior of the valve cage 210. Communication with the hollow center 232 of the mode selector 211 is provided by means of the passage 226.

Threaded into the hollow center of the slidable stem 211 is the speed control member 212, which in function is analogous to the element 162 described earlier.

FIGURE 6 shows the position of the mode selector control for the single fire mode of operation, which will now be described. That is, the valve stem 211 has been moved to the farthest right or innermost position, as shown in the drawings. (It will be seen that the mode selector 211 is provided with the very small bleeder port 211a slightly to the left of O-ring 222. This allows air trapped behind O-ring 222 as the mode selector is moved to the single fire position, to escape through its hollow center 232, through the bleeder port 211a, into the relieved portion 220, past the O-ring 223, into the relieved portion 229 of the mode selector, through the passage 230 in the valve cage, into the relieved area 214, and out of the passage 213 to atmosphere.) With the trigger and valve stem 200 in the lowermost or inoperative position, air v under pressure from the chamber 14 can follow the path described earlier, forcing the firing valve piston 22 to its 1 1 closed position. At this time, the O-ring 203 on the valve stem 200 is in contact with the inner surface of the valve sleeve 204, preventing further movement of compressed air through the valve stem.

Upon actuation of a suitable trigger (or set of triggers if utilizing the trigger-safety combination described earlier) the valve stem 200 will be moved to its upper position shown in FIGURE 7. At this time, the O-ring 202 comes into contact with the inner surface of the valve sleeve 204, blocking off communication between air in the reservoir 14 and the space above the firing valve piston 22. Shortly after this O-ring 202 moves into contact with the internal surface of the valve sleeve 204, the O-ring 203 will move into the relieved space 207, permitting the compressed air to flow from the space above the firing valve piston, through the passage 107, into the relieved space 205, through the passage 209 and past the relieved diameter portion 201, past the O-ring 203 into the relieved space 207, and into the passage 227 in the cap.

As is clearly shown in the drawings, this passage 227 communicates with the relieved space 213 on the valve cage, and in turn communicates via the passage 228 with the relieved portion 220 on the inner surface of the valve cage. With the mode selector control 211 in the single fire position of FIGURE 6, the air can pass into the relieved portion 220, past the O-ring 223, into the relieved portion 229 of the mode selector control, through the passage 230 in the valve cage and into the relieved area 214, then out the passage 231 to atmosphere. As explained earlier, this reduction in pressure on the top surface 22a of the firing valve 22 will permit the valve to be opened by compressed air acting on its under surface 22b, thereby admitting compressed air into the working cylinder to fire the tool. Upon release of the trigger, compressed air acting on the enlarged portion 200a will force the valve stem 200 to its down or inoperative position. This action first of all effects a sealing of the exhaust passage outlined above, by means including the O-ri-ng 203, and shortly thereafter opens the passages, including the recess 208, permitting compressed air from the chamber 14 to flow into the space above the firing valve piston 22, effecting its closure.

To operate the modification of the invention in the auto fire mode of operation, the mode selector control valve 211 is moved to the left or outer position as shown in FIGURE 7. Upon actuation of the trigger or other firing control, the valve stem 200 is moved upward, permitting air in the space above the firing valve piston to flow through the passage 107, the relieved space 205, through the passage 209 and past the reduced diameter portion 201, past the O-ring 203, into the relieved area 207, and through the passages 227 and 228. At this time, the compressed air can flow into the hollow center 232 of the mode selector Valve 211, past the conical tip 233 of the throttling valve 212, through the passage 226 into the relieved area 221, through the passage 234 in the valve cage into the relieved area 215, and through the passage 158 into the interior of the auto fire valve.

It will be recalled that at this time, the main driving piston 44 is in its uppermost position, so that its upper surface is in contact with the valve actuator 146, urging it against the bias of spring 156 to its uppermost position, wherein the resilient valve 154 is raised off its seat. This permits the air passing through the passage 158 to flow around the resilient valve 154, through the hollow stem of the actuator 146, through the cutaway portion 148 of the actuator, the relieved portion 172 in the top of the piston 44, through the firing valve seat 30, around the exhaust valve Washer 32, and through the passages 66 and 68 to atmosphere. It will be recognized that this last described exhaust fiow is simply the ordinary exhaust for air within the working cylinder.

This exhausting of air from the space above the firing valve piston 22 permits it to be opened by air acting on 12 its underside as described above, and initiates the first downward stroke or cycle of the tool.

When the working piston 44 reaches its lowermost position, the compressed air in the working cylinder will act upwardly, through the stem of the valve actuator 146, overcoming the resistance of the spring 156 and lifting the valve 154 off its seat. This will permit the compressed air to pass through the ports 150, the relieved portion 152, past the valve 154, through the ports 158, 234, and 226, past the tip 233 of the speed control valve, through the hollow center 232 of the mode selector valve, through the pasages 228 and 227, into the relieved space 207, the space 201, through the port 209, through the passage 107 and into the space on top of the firing valve 22. By virtue of the previously described springless firing valve (US. Patent No. 3,170,487), as compressed air following the path outlined increases the pressure on the surface 220, the firing valve 22 will be forced downwardly to its closed position.

As stated before, when the firing valve 22 reaches its closed position, the exhaust valve washer 32 comes out of contact with the O-ring 64, permitting air within the working cylinder to escape past the washer 32, and through the passages 66 and 68 to atmosphere. When the pressure in the working cylinder is reduced, the spring 156 will cause the valve 154 to close; this reduction in pressure also permits compressed air in the air return reservoir 56 to act on the underside of the piston, forcing it to its uppermost position as explained previously.

Upon reaching this uppermost position, the top of the piston contacts the valve actuator 146 exhausting the compressed air above the firing valve 22, and the above described cycle is repeated.

T o briefly review this modification of the invention, its single fire mode of operation is largely conventional. That is, upon movement of a suitable trigger to its operative position, the supply of air to the space above the firing valve piston is first cut off, and then this space is opened to atmosphere. This reduction in pressure permits the firing valve 22 to open, driving the working piston in a working stroke. Release of the trigger restores pressure to both sides of the valve 22, closing it and permitting the return of the working piston. If the trigger is not released, the working piston will simply remain in its down position, all exhausts from the working cylinder being closed.

To begin the auto fire mode of operation, the operator simply moves the mode selector valve 211 to its outermost position. Now, upon pulling the trigger to its operative position, the supply of compressed air to the space above the firing valve piston 22 is cut off as before; and then this space is vented to atmosphere, but this time through the auxiliary exhaust passage as described above, which it will be recalled, includes the normal exhaust from the Working cylinder of the tool and the passages 226, 221 and 234 leading from the hollow center 232 to the passage 158 leading to the interior of the auto fire valve. When the pressure above the firing valve piston is thus reduced, it opens, admitting compressed air into the working cylinder to drive the working piston in its power stroke. As the working piston 44 completes its down or (working stroke, compressed air passes through the auto fire valve, lifting the valve member 154 if it is not already up, through the mode selector valve, and back into the space above the firing valve piston 22, causing it to close. Closing of the firing valve 22 vents the space within the working cylinder to atmosphere, permitting the compressed air in the return reservoir 56 to return the working piston to its uppermost position, and at the same time permitting the member 154 to return to its seat under action of the spring 156. Upon return of this piston to its uppermost position, it mechanically reopens the auto fire valve by lifting the member 154 from its seat, thus permitting the compressed air in the space above the firing valve piston to exhaust through the same passages (hollow center 232, passage 226, passage I58 and so forth) utilized before; that is, including a flow path through the auto fire valve and the conventional exhaust from the working cylinder of the tool. In this manner, the tool will repetitively cycle, and insure that each cycle includes a complete return stroke, until the trigger is released or returned to its inoperative position. When the trigger is returned to this inoperative position, compressed air from the reservoir 14 flows through the normal passages into the space on top of the firing valve piston 22, effecting its closure, and the consequent opening of the exhaust passages from the working cylinder of the tool.

While the invention has been described in terms of a specific exemplary embodiment, it will be apparent to the skilled worker in the art, that the concept described herein is very broad. Hence, no limitations are to be inferred from the preceding specific description except insofar as set forth in the following claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a pneumatic fastener applying device including a working cylinder and a piston reciprocable therein in a cycle including opposed working and return strokes, the improved control structure comprising:

(a) a firing valve adapted to control the admission of compressed fluid into said cylinder;

(b) means for controlling the initial opening of said firing valve;

(c) means for utilizing at least a portion of the compressed fluid admitted to said cylinder to effect closing said firing valve; and

(d) means actuated by said working piston at substantially the end of its return stroke operative to control reopening of said firing valve to initiate a new cycle.

2. The control structure claimed in claim 1 wherein said firing valve is pneumatically actuated, and wherein said means for controlling the initial opening said firing valve comprises a selective control valve movable from an inoperative position to an operable position, said selective control valve being effective to control the initial opening of said firing valve.

3. The fastener applying device claimed in claim 2 including means for metering said compressed fluid utilized to effect closing of said firing valve whereby to vary the cycling rate of said device.

4. The control structure claimed in claim 2 wherein said means for utilizing at least a portion of the compressed fluid admitted to said cylinder for closing said firing valve comprises a normally closed valve, said valve being opened by movement of said selective control valve from said inoperative position to said operable position.

5. The control structure claimed in claim 4 wherein said means actuated by said working piston at substantially the end of its return stroke and operative to reopen said firing valve, comprises an exhaust valve disposed between said cylinder and said normally closed valve and operative to establish an auxiliary exhaust passage with said pneumatically actuated firing valve.

6. The control structure claimed in claim 5 wherein said exhaust valve includes an actuator extending into said cylinder adjacent its upper end.

'7. In a pneumatic fastener applying device for use with a supply of air under pressure including a working cylinder and a piston reciprocable therein in a cycle including opposed working and return strokes, a firing valve adapted to control the admission of pneumatic power into said cylinder, a fastener driver associated with said piston, a drive track, and means for successively feeding a plurality of fasteners into said drive track, whereby each 14 working stroke is effective to drive a fastener, improved control structure comprising:

(a) a selective control valve movable from an inoperative position to a single fire position and to an auto fire position;

(b) first means responsive to movement of said selective control valve from said inoperative position to said single fire position and back to said inoperafire position to cause said device to perform a complete working cycle; and

(c) second means responsive to movement of said select-ive control valve from said inoperative position to said auto fire position to cause said device to continuously cycle until said control valve is moved out of said auto fire position.

8. The fastener applying device claimed in claim 7 including resistance creating means associated with said selectiv control value and effective after movement of said selective control valve to said single fire position, whereby an operator is able to select easily the single fire or the auto fire mode of operation.

9. The fastener applying device claimed in claim 8 wherein said resistance creating means comprises a member acted upon on only one side by pneumatic power in its initial position, and means movable with said selective control valve a pre-determined distance before contacting said member, said predetermined distance establishing said single fire position, further movement of said selective control valve being effective to move said resistance creating means whereby pneumatic power acts on both sides of said resistance creating means.

10. The fastener applying device claimed in claim 7 including a workpiece responsive actuating member movable from an inoperative position to an operative position, a trigger responsive actuating member movable from an inoperative position to a single fire position and to an auto fire position, a firing element operatively associated with said actuating members and movable from an inoperative position to a single fire position and to an auto fire position, said firing element also being operatively associated with said selective control valve, whereby movement of said workpiece responsive actuating member to said operative position and movement of said trigger responsive actuating member to said single fire position effects movement of said firing element and said selective control valve to said single fire position, and movement of said workpiece responsive actuating members to said operative position and movement of said trigger responsive actuating member to said auto fire position effects movement of said selective control valve to said auto fire position.

ill. In a pneumatic fastener applying device including a working cylinder and a piston reciprocable therein in a cycle including opposed working and return strokes, a firing valve adapted to control the admission of pneumatic power into said cylinder, a fastener driver associated with said piston, a drive track, and means for successively feeding a plurality of fasteners into said drive track, whereby each working stroke is effective to drive a fastener, the improved control structure comprising: a control valve selectively movable from an inoperative to a single fire and to an auto fire position, and means responsive to movement of said control valve to effect the actuation of said firing valve whereby said device may be operated selectively in a single fire and an auto fire mode of operation.

I2. A fastener applying device for use with a source of pneumatic power comprising:

(a) a working cylinder having a piston reciprocable therein, in a cycle having opposed working and return strokes;

(b) a fastener driver associated with said position;

(c) means for feeding a fastener into position to be driven by said fastener driver after each return stroke;

(d) a pneumatically actuated firing valve for controlling the admission of pneumatic power to said cylinder;

(e) a selective control valve movable from an inoperative position to a single fire position and to an auto fire position, said inoperative position establishing communication between said source of pneumatic power and said firing valve, said single fire position establishing a normal exhaust passage communicating with said firing valve and causing said firing valve to open, and said auto fire position closing off said normal exhaust passage;

(f) means for utilizing at least a portion of the pneumatic power admitted to said cylinder to effect the closing of said firing valve, said means including a normally closed valve adapted to be opened by movement of said selective control valve to said auto fire position; and

(g) means actuated by said working piston at substantially the end of its return stroke operative to control reopening of said firing valve to initiate a new cycle, said means being effective to establish an auxiliary exhaust passage communicating with said firing valve after said piston has completed its return stroke.

13. The fastener applying device claimed in claim 12 including resistance creating means associated with said selective control valve and effective after movement of said selective control valve to said single fire position,

whereby an operator is able to select easily the single fire or the auto fire mode of operation.

14. The fastener applying device claimed in claim 13 wherein said resistance creating means comprises a member acted upon on only one side by pneumatic power in its initial position, and means movable with said selective control valve a pre-determined distance before contacting said member, said pre-determined distance establishing said single fire position, further movement of said selective control valve being effective to move said resistance creating means whereby pneumatic power acts on both sides of said resistance creating means.

15. The fastener applying device claimed in claim 12 including means for metering said compressed fluid utilized to effect closing of said firing valve whereby to vary the cycling rate of said device in its auto fire mode of operation.

167 The fastener applying device claimed in claim 12 wherein said means actuated by said working piston at substantially the end of its return stroke and operative to reopen said firing valve comprises an auto fire exhaust valve, means biasing said auto fire exhaust valve to a closed position, and an actuator extending into said cylinder near the upper end thereof in a position to be contacted by said piston at substantially the end of its return stroke, whereby said biasing means is overcome and said auxiliary exhaust passage is established for said firing valve.

17. The fastener applying device claimed in claim 12 including a pair of independent actuating members, each said actuating members being movable from an inoperative position to at least one operative position, said actuating members being operatively associated with said selective control valve whereby only movement of both said actuating members to said operative positions is effective to move said selective control valve from said inoperative position.

18. The fastener applying device claimed in claim 17 wherein one of said actuating members is responsive to a manual trigger, and wherein the other of said actuating members is responsive to the position of said device with respect to a workpiece.

19. The fastener applying device claimed in claim 12 including a workpiece responsive actuating member movable from an inoperative position to an operative position, a trigger responsive actuating member movable from an inoperative position to a single fire position and to an auto fire position, a firing element operatively associated with said actuating members and movable from an inoperative position to a single fire position and to an auto fire position, said firing element also being operatively associated with said selective control valve, whereby movement of said workpiece responsive actuating member to said operative position and movement of said trigger responsive actuating member to said single fire position effects movement of said firing element and said selective control valve to said single fire position, and movement of said workpiece responsive actuating member to said operative position and movement of said trigger responsive actuating member to said auto fire position etfects movement of said selective control valve to said auto fire position.

26. In a pneumatic fastener driver having a cylinder (38), a work piston (44) reciprocable in said cylinder from an initial position to a work piston stop (Sit) so as to define a work stroke and a return stroke, fastener driving means (47) actuated by said piston, fastener feeding means (58) to position a succession of fasteners into position to be driven by said driving means on each work stroke, a return reservoir (56), valve controlled port means (52, 54) for admitting compressed air from said cylinder to said return reservoir when said work piston abuts said stop, and pneumatically operated means to reciprocate said work piston, said means including a firing valve piston (22), the improvement which comprises:

(a) a movable selective control valve (116),

(b) a first compressed air passage system (104, 108,

106 and 1417) normally open for admitting compressed air from a reservoir (14) to one side (22a) of said firing valve piston normally to hold said firing valve piston on a seat (30),

(c) a first exhaust passage system (107, 106, 108, 134, 112, 110 and 114) for venting air from said one side of said firing valve piston to atmosphere,

(d) a second exhaust passage system (66, 68) for venting air from one side of said work piston to atmosphere when said work piston is at its initial position,

(e) a third exhaust passage system (170, 158, 1519, 148, 172, 66 and 68) for venting air from said one side of said firing valve piston to atmosphere,

(f) a second compressed air passage system (150, 158, 161) and for admitting compressed air to said one side of said firing valve piston,

(g) the other side (22b) of said firing valve piston being exposed to compressed air from said reservoir (14) and said other side (22b) having less effective area acted upon by said compressed air than said one side (22a) of said firing valve piston,

(h) first sealing means (121) carried by said selective control valve (116) and normally preventing exhaust through said first exhaust passage system,

(i) second sealing means (121)) carried on said selective control valve (116) and normally maintaining said first compressed air passage system open, whereby said firing valve piston remains on said seat and said work piston remains at its initial position,

(j) means (86, 88 and 128) to move said selective control valve so as to cause said first sealing means to open said first exhaust passage system to atmosphere and to move said second sealing means so as to close said first compressed air passage system, whereby the air at said one side of said firing valve piston is vented to atmosphere through said first exhaust passage system while compressed air remains admitted to said other side of said firing valve piston whereby said firing valve piston moves off its said seat,

(k) third sealing means (64) to close said second exhaust passage system when said firing valve piston moves off its seat, whereby compressed air is a mitted to said work piston todrive said work piston to the said stop and to drive a fastener into work, said means (86, 88 and 128) being selectively movable so as to cause said selective control valve and the said first sealing means and said second sealing means to return to their normal and original positions whereby, due to the greater effective area of said one side of said firing valve piston as compared to said other side of said firing valve piston, said firing valve piston returns to its said seat and said third sealing means opens said second exhaust passage system, whereby the compressed air in said return reservoir causes said work piston to return to its initial return position, thus completing a single cycle of said work piston,

(l) a normally closed, resiliently biased, valve (164) in the said systems including the passages (160 and 170) (m) a resiliently biased auto fire exhaust valve (154) having a work piston actuatable extension (146), said auto fire exhaust valve being located in the said systems which include the passages (150 and 158),

(n) actuating means (168) carried on said selective control valve, said actuating means being normally spaced from said valve (164), and

(o) the means (86) also being selectively movable beyond the position to which it and the means (88) are initially moved in moving the selective control valve so as to drive the work piston to the said stop (rather than to move said means (86) to its initial position for the said single cycle), whereby also to move said selective control valve beyond its initial movement, such further movement of said selective control valve resulting in continuous repetitive cycles of said work piston by causing said actuating means (168) to engage and hold open said valve (164), said second sealing means continuing to close said first compressed air passage system and fourth sealing means (122) carried on said selective control valve and now closing said first exhaust passage system, whereby as said Work piston is moved from its initial position towards said stop said resiliently biased auto fire exhaust valve is opened by the com pressed air acting on said piston, such last mentioned compressed air thereby passing through the now open said second compressed air system to said one side of said firing valve piston whereby, due to the greater effective area of said one side of said firing valve piston as compared to said other side of said firing valve piston, said firing valve piston returns to its seat thus cutting off the supply of compressed air to said work piston and said third sealing means opens said second exhaust passage system whereby the resiliently biased auto fire exhaust valve closes and the compressed air in said return reservoir causes said work piston to return to its initial return position wherein said work piston engages said extension and again forces open said auto fire exhaust valve thereby opening the said third exhaust passage system so that air at said one side of said firing valve piston is now vented to atmosphere through this said third exhaust passage system while said other of said firing valve system remains exposed to compressed air and the cycle is repeated continuously until the selective control valve is moved so as to disengage said actuating means (168) from said valve (164).

21. The fastener driver of claim 2%) including means (162) to control the speed of repetitive cycles occurring while said actuating means (168) holds said valve (164) open, said control means (162) comprising a tapered member movable within the passage (160) so as to vary the throughput area of said passage whereby to control the rapidity with which compressed air passes through said passage (160) to said one side of said firing valve to close same and whereby, when said auto exhaust fire valve is opened by said work piston engaging said extension (146), to control the rapidity of exhaust through said third exhaust passage system from said one side of said firing valve piston to open same, the opening and closing of said firing valve piston controlling the cycling of said work piston.

22. The fastener driver of claim 21 including means (163) associated with said control means to limit the maximum throughput area of said passage 23. The fastener driver of claim 20 including resistance means (96, 98) encountered when said selective control valve is moved from its said normal original position to its position for single fire, whereby an operator is appraised of the fact that said selevtice control valve is at such single fire position.

24. The fastener driver of claim 20 in which said means (86, 88, and 128) to move said selective control valve includes resiliently biased elements (82 and 84) having recesses (82a and 84a), by-pass regions (82b and 84b) and shoulders (82c and 840), the element (128) being actuated by said shoulders, and a sleeve (24) engaged by said element (82) when said selective control valve is moved to its single fire position, said element (84) having a clearance (132) to allow said element (84) to move free of said sleeve (94).

25. In a pneumatic fastener applying device including a working cylinder and a piston reciprocable therein in a cycle including opposed working and return strokes, the improved control structure comprising:

(a) a pneumatically actuated firing valve adapted to control the admission of compressed fluid into said cylinder;

(b) remote Valve means operative to establish a normal exhaust passage for causing said firing valve to open;

(c) structure defining an auxiliary exhaust passage operative to open said firing valve to exhaust when said normal exhaust passage is sealed;

(d) mode selector valve means operative selectively to seal said normal exhaust passage and open said auxiliary exhaust passage, and to seal said auxiliary exhaust passage and open said normal exhaust passage; and

(e) means for utilizing at least a portion of the compressed tluid admitted to said cylinder to effect closing said firing valve, said last named means being operative only when said mode selector valve means has sealed said normal exhaust passage and opened said auxiliary exhaust passage.

26. A fastener applying device for use with a source of pneumatic power comprising:

(a) a working cylinder having a piston reciprocable therein, in a cycle having opposed working and return strokes;

(b) a fastener driver associated with said piston;

(c) means for feeding a fastener into position to be driven by said fastener driver after each return stroke;

(d) a pneumatically actuated firing valve for controlling the admission of pneumatic power to said cylinder;

(e) a remote control valve movable from an inoperative position to an operative position, said inoperative position establishing communication between said source of pneumatic power and a portion of said firing valve whereby said firing valve is closed, said operative position establishing communication between said firing valve and a mode selector valve;

(f) a mode selector valve movable from a single fire position to an auto fire position, said single fire position establishing a normal exhaust passage for said firing valve through said remote control valve when said remote control valve is in its operative position, whereby pneumatic power is admitted to said working cylinder, said auto fire position closing off said normal exhaust passage and establishing an auxiliary exhaust passage for said firing valve when said remote control valve is in its operative position;

(g) means for utilizing at least a portion of the pneumatic power admitted to said cylinder to effect closing of said firing valve after said piston has completed a working stroke, said means being effective only when said mode selector valve is in said autofire position; and

(h) means actuated by said working piston at substantially the end of its return stroke operative to control reopening of said firing valve to initiate a new cycle by opening the auxiliary exhaust passage communicating with said firing valve said last named means being effective only when said mode selector valve is in said auto-fire position.

27. The fastener applying device claimed in claim 26 wherein said means actuated by said working piston at substantially the end of its return stroke and operative to reopen said firing valve comprises an auto fire exhaust valve, means biasing said auto fire exhaust valve to a closed position, and an actuator extending into said cylinder near the upper end thereof in a position to be contacted by said piston at substantially the end of its return stroke, whereby said biasing means is overcome and the auxiliary exhaust passage is established for said firing valve.

28. In a fastener applying device including a cylinder, a cylinder, a piston reciprocable in said cylinder between a rest position and a driven position, fastener driving means actuated by said piston, means for successively placing fasteners in position to be driven by said fastener driving means, one-stroke movement of said piston from said rest position to said driven position eflecting a complete driving of a said fastener, a supply of fluid power for actuating said piston, a firing valve controlling application of fluid power from said supply to said piston, said firing valve having a closed position and an open position, said firing valve in its closed position cutting off said piston from said supply of fluid power and opening said cylinder to atmosphere, said firing valve in its open position admitting fluid power to said piston and closing said cylinder to atmosphere, first valve means having an inoperative position and an operative position, said first valve means in its inoperative admitting fluid power to said firing valve to hold said firing valve in its closed posiwill move to its open position so as to admit fluid power to said cylinder to drive said piston to its driven position, and means to return said piston to its rest position, the improvement which comprises:

(a) a second valve means (211, 212) having a single fire position and an auto fire position,

(b) a second exhaust passage (232, 226, 234, 158, 148, 172, 66, 68) from said firing valve, said second valve means in its single fire position closing said second exhaust passage and opening said first exhaust passage, and said second valve means in its auto fire position closing said first exhaust passage and opening said second exhaust passage, movement of said first valve means to its operative position opening said firing valve to exhaust through said second exhaust passage when said second valve means is in its auto fire position, whereby said firing valve moves to its open position, said cylinder is closed to atmosphere and said piston is driven as before,

(0) means (148, 158, 234, 226, 232) to utilize a portion of the fluid power which moved said piston to its driven position to move said firing valve to its closed position, whereby said cylinder is opened to atmosphere and said piston is returned to its rest position,

(d) a third valve (154) arranged to close said second exhaust passage when said cylinder is opened to atmosphere by the closing of said firing valve, and

(e) trip means (146) actuated by said piston when said piston returns to its rest to move said third valve so as to reopen said second exhaust passage whereby, so long as said first valve means is kept in its operative position and said second valve means is kept in its auto fire position, the piston will continue to cycle as described.

No references cited.

GRANVILLE Y. CUSTER, JR., Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,278,103 October 11, 1966 George C. Juilfs et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 3, line 40, for "linear" read liner column 4, line 2, for "position" read piston line 13, for "admitting" read admitted column 6, line 63, for "first" read fire column 8, line 50, after "auto fire" insert valve column 9, line 1, for "firing" read fire column 14, lines 8 and 9, for "inoperafire" read inoperative line 18, for "selectiv" read selective line 48, for "members" read member line 72, for "position" read piston column 19,

line 30, strike out "a cylinder" line 47, after "inoperative" insert position Signed and sealed this 29th day of August 1967.

(SEAL) ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner of Patents

Claims (1)

1. IN A PNEUMATIC FASTENER APPLYING DEVICE INCLUDING A WORKING CYLINDER AND A PISTON RECIPROCABLE THEREIN IN A CYCLE INCLUDING OPPOSED WORKING AND RETURN STROKES, THE IMPROVED CONTROL STRUCTURE COMPRISING: (A) A FIRING VALVE ADAPTED TO CONTROL THE ADMISSION OF COMPRESSED FLUID INTO SAID CYLINDER; (B) MEANS FOR CONTROLLING THE INITIAL OPENING OF SAID FIRING VALVE; (C) MEANS FOR UTILIZING AT LEAST A PORTION OF THE COMPRESSED FLUID ADMITTED TO SAID CYLINDER TO EFFECT CLOSING SAID FIRING VALVE; AND (D) MEANS ACTUATED BY SAID WORKING PISTON AT SUBSTANTIALLY THE END OF ITS RETURN STROKE OPERATIVE TO CONTROL REOPENING OF SAID FIRING VALVE TO INITIATE A NEW CYCLE.

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