Pneumatic device for driving headed objects

Abstract

A pneumatic device for driving headed objects, such as nails and the like, characterized by a housing including therein a pneumatically actuated ram supported for reciprocatory motion along a linear path and adapted to strike in sequence a plurality of headed objects serially positioned within the path of the ram, a magazine supported by the housing adapted to advance a file of discrete headed objects along a linear path extended toward the housing, a cyclically operable gate for serially extracting the headed objects from the file and a pneumatic control circuit for imposing on the device a predetermined operational sequence.

Description

BACKGROUND OF THE INVENTION

The invention relates to impacting devices, and more particularly to a manually operable pneumatic device for driving headed objects such as nails and the like, including a pneumatically operated ram and a magazine adapted to receive a plurality of discrete headed objects from a feeder, such as that disclosed and claimed in application Ser. No. 450,656, filed Mar. 13, 1974, and to serially deliver the objects to the ram. It is here noted that while the device which embodies the principles of the instant invention has particular utility in the driving of nails, the device can be employed in driving headed objects, of a general nature, including heads and elongated shanks projected from the heads thereof. Therefore, while for the sake of convenience reference frequently is made to nails in the following description and claims, it is to be understood that the utility of the device is not limited to the driving of nails.

The prior art, of course, includes numerous pneumatically actuated nailing devices suited for use in joining workpieces with nails, clips and similar fastening devices. In instances where it is desirable to employ magazines for feeding nails and the like to pneumatically actuated driving devices, it has been suggested that spring-loaded magazines, such as that disclosed by U.S. Pat. No. 2,979,725, be provided. Of course, while a use of spring-loaded magazines may be acceptable, in certain environments, it should be apparent that substantial amounts of time normally are required to effect a loading of such magazines. Moreover, such magazines frequently will not accept fastening devices of a conventional configuration but require fastening devices specifically configured to be received in the magazine. In order to overcome these difficulties, it has been suggested that magazines adapted to handle nails, and similar fastening devices, temporarily joined through the use of adhesive strips be employed.

As can be appreciated by those familiar with the design, fabrication, and use of nailing devices for fabrication purposes, it is, in the interest of economy and for other reasons, highly desirable to provide a simplified and economic pneumatic nailing device which utilizes readily available fastening devices, such as nails, or a conventional design and having a general utility. It is therefore the purpose of the instant invention to provide a manually operable pneumatic nailing device which includes a magazine for serially advancing in single file a plurality of discrete, headed objects, such as common box nails, and a gate mechanism for sequentially transferring the nails from the magazine into coaxial alignment with a pneumatically actuated nailing ram.

OBJECTS AND SUMMARY OF THE INVENTION

It is therefore an object of the instant invention to provide a pneumatic driving device which overcomes the aforementioned difficulties and disadvantages.

It is another object of the instant invention to provide a manually operable, portable driving device particularly suited for use in driving headed objects serially delivered thereto.

It is another object to provide a pneumatic device including a portable housing, a pneumatic nailing ram, and a manually operable trigger circuit including a nail feeder supported by the housing for serially positioning a plurality of discrete objects within the path of the nailing ram.

It is another object to provide a pneumatic device which includes a housing, a nail-driving ram supported within the housing, and a nail feeder including a gravity-fed magazine for serially delivering a plurality of discrete nails to the housing, and a pneumatically actuated gate for sequentially extracting nails from the magazine and positioning the nails within the path of the ram.

These and other objects and advantages are achieved through a nailing device which includes a portable housing, a pneumatically actuated nail-driving ram supported within the housing, and nail-feeding means for serially delivering discrete nails to the ram, including a magazine adapted to be coupled with a nail-loading mechanism for receiving therefrom a plurality of discrete nails arranged in single file and for serially advancing the file of nails to a gate provided within the housing for extracting the nails from the magazine and sequentially positioning the nails within the path of the ram, as will hereinafter become more readily apparent by reference to the following description and claims in light of the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partially sectioned side view of a pneumatic nailing device including a nail magazine which embodies the principles of the instant invention.

FIG. 2 is a top plan view of the device shown in FIG. 1.

FIG. 3 is a bottom plan view of the device.

FIG. 4 is a fragmented, partially sectioned view taken generally along line 4--4 of FIG. 1.

FIG. 5 is a fragmented, partially sectioned view, on an enlarged scale, of a trigger valve provided within a control circuit for initiating operation of the nailing device, shown in FIG. 1.

FIG. 6 is a fragmented, partially sectioned view of a nosepiece for the housing of the device including therein a gate for extracting nails from the magazine.

FIG. 7 is a fragmented, partially sectioned view of the nosepiece depicted in FIG. 6, but rotated through 90.degree. with respect thereto.

FIG. 8 is a sectioned, top plan view of the nosepiece shown in FIGS. 6 and 7.

FIG. 9 is a fragmented, partially sectioned view, taken generally along line 9--9 of FIG. 2.

FIG. 10 is a fragmented, partially sectioned view of a pilot valve, provided as shown in FIG. 9.

FIG. 11 is a fragmented, partially sectioned, schematic view illustrating the control circuit provided for the nailing device.

FIG. 12 is a fragmented side elevation illustrating a work engaging leg coupled with the nosepiece and a nail guide provided for positioning nails in the path of the nailing ram.

FIG. 13 is a fragmented, partially sectioned view of the nosepiece illustrated in FIG. 12, rotated through 90.degree. .

FIG. 14 is a fragmented, partially sectioned view taken generally along line 14--14 of FIG. 13.

FIG. 15 is a cross sectional view taken generally along line 15--15 of FIG. 13.

FIG. 16 is a cross sectional view taken generally along line 16--16 of FIG. 13.

FIG. 17 is a perspective view of the nosepiece.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now with more specificity to the drawings, wherein like reference characters designate like or corresponding parts throughout the several views, there is shown in FIG. 1 a pneumatic nailing device, generally designated 10, which embodies the principles of the instant invention. The nailing device 10 includes a housing 12, within which there is seated for reciprocation, along a rectilinear path, an axially reciprocable nailing ram 14. The housing includes a casting 15 and a nosepiece 16 secured to the casting by suitable screws 17. A nail magazine 18 is mounted on the housing 12, as shown, and serves to advance in single file a plurality of discrete nails, not designated, to the nosepiece 16. The nails are of a conventional configuration and include diskshaped heads. Such nails are typified by those known as "box nails."

MAGAZINE

The nail magazine 18 includes a pair of rails 20 disposed in parallelism and spaced a distance substantially equal to the diameter of the shank of nails, FIG. 4, so that the nails are received and advanced in single file therebetween. As best shown in FIG. 4, each of the rails 20 is the mirror image of the other and includes a relief 22, partially defined by a shoulder 24. The shoulder 24, in turn, engages the lowermost surfaces of the heads of the nails and supports the nails in suspension as the nails are advanced in single file between the rails 20.

Projected outwardly from each of the rails 20 there is a flange 26 having formed therein suitable openings coincident with internally threaded bores formed in the housing 12 for receiving screws 28. These screws serve to unite the nail magazine 18 with the housing 12. Additionally, a cover plate 30 is affixed to the flanges 26 for closing the magazine adjacent to the reliefs 22 for forming an enclosure for restraining the nails against substantial axial motion while they are confined within the magazine.

As illustrated in FIG. 1, the magazine 18 is supported at an included angle of inclination of approximately 28.degree. relative to the longitudinal axis of the nailing ram 14 so that the nails are permitted to gravitate through the magazine 18 as they are advanced toward the housing. Thus, as a practical matter, the nailing device 10 is fed by the magazine 18 when the device is employed in any disposition such that the longitudinal axis of the nail magazine 18 is supported at an angle of inclination relative to a horizontal plane. Therefore, it can be appreciated that the nailing device 10 is, in practice, employed for driving nails in vertically oriented surfaces as well as in surfaces horizontally oriented.

As best illustrated in FIGS. 6, 7 and 8, the nosepiece 16 includes a barrel 32 for serially receiving and aligning nails delivered thereto preparatory to being struck by the nailing ram 14. Consequently, the barrel 32 is coaxially aligned with a bushing 34, FIG. 7, including a bore 36 which serves as a guide for the nailing ram 14, as axial motion is imparted thereto. The barrel 32 is integral with a base block 38 of the nosepiece 16. The base block has defined therein an elongated slot 40, as best illustrated in FIGS. 6, 11 and 17, which generally conforms to the shape of a box nail and extends downwardly into the upper portion of the barrel 32. It is important to understand that the slot 40 is disposed in substantially coplanar alignment with the passage defined between the rails 20 of the magazine so that the nails are caused to gravitate into the upper portion of the barrel 32 as they exit from between the rails.

Preferably, the slot 40 is so oriented that the longitudinal axis of the shank of a nail supported therein defines an included angle of approximately 20.degree. with respect to a reference plane extended in substantial parallelism with the longitudinal axis of the magazine 18 and intersected with the longitudinal axis of the path of the ram 14, along the full length thereof. This orientation of the slot 40 serves to enhance control of the nails as they are discharged into the barrel 32, preparatory to being struck by the ram 14. The enhancing effect of the slot 40 can be appreciated when it is recognized that in order to achieve a positive delivery of the nails, in sequence, to the barrel 32, nail travel along a path transversely related to the path of the file of nails is preferred for the sake of simplicity in design. It has been found that by maintaining the shanks of the nails in the magazine so oriented that the shank of each first-in-line nail enters the barrel 32 as it is discharged from the magazine 18, it is possible to introduce the head portion of the nail into the barrel 32 by imparting thereto motion transversely related to the longitudinal axis of the magazine 18.

Moreover, it is to be understood that in order for the first-in-line nail to be properly oriented, preparatory to its delivery to the barrel 32 at the beginning of a cycle of operation, the nail must come to rest in a pre-delivery disposition wherein the nail is caused to extend through the aforementioned reference plane, as best illustrated in FIG. 6. As should readily be apparent, this facilitates a positive supporting of a single nail against displacement into the barrel 32, prior to pivotal motion being imparted thereto, in a manner hereinafter more fully described, in a plane substantially transversely related to the longitudinal axis of the magazine 18 for purposes of delivering the nail into the barrel. Thus positive control over the position of each nail is maintained and jamming of the device 10 resulting from a simultaneous delivery of portions of more than one nail to the barrel 32 substantially is avoided.

GATE

Motion transversely related to the axis of the magazine is imparted to each of the nails by a gate 42 seated in the base block 38, in the path of the nails as they are advanced through the magazine 18, as best illustrated in FIG. 14. The gate 42 includes a reciprocatory shuttle 44 seated within a channel 46 and supported for rectilinear motion between a nail-receiving position and a nail-deliver position, whereby a nail delivery stroke, followed by a shuttle-return stroke, is accommodated.

The shuttle 44 comprises an elongated bar having a pair of relieved portions which serve as a nail restrainer portion 48 and a nail-delivery cup 50, arranged in juxtaposition along one surface of the bar. The restrainer 48 is so arranged as to be aligned with the magazine 18, when the shuttle is in its nail-delivery position, and the nail-delivery cup 50 is so arranged as to be aligned, simultaneously, with the barrel 32. The restrainer portion 48 has a depth such that the shank of each leading nail advanced by the magazine 18 is received within the channel 46, while the head thereof is restrained against entry into the channel by the restrainer portion. The delivery cup 50 has a radius substantially equal to the radius of the barrel 32 and greater than that of the head of each of the nails so that the head of each leading nail is received within the cup 50. when the shuttle is in its nail-receiving position. Consequently, it is to be understood that when the shuttle 44 is disposed in a nail-receiving position, the cup 50 is aligned with the file of nails confined within the nail magazine 18 and receives the leading nail. When the shuttle is in its nail-delivery position, the nail, previously received, is released from the shuttle 44 and permitted to advance through the barrel 32, while the file of nails is concurrently restrained within the magazine 18 by the restrainer portion 48.

Referring now to FIG. 6, it is noted that the uppermost portion of the shank of each leading nail, upon being received by the slot 40, is supported in an inclined disposition by an inclined surface 52, which intersects the barrel 32. Concurrently, the lowermost portion of the shank of the nail projects angularly from the barrel 32 at the opposite side thereof. Therefore, the barrel 32 is provided with a planar surface 54 lying in a plane extended through the diameter of the barrel, as best illustrated in FIGS. 6, 15, and 16. The outer edge portion of this surface serves to engage an extended portion of the nail, adjacent the point end thereof, for purposes of supporting the nail in its pre-delivery disposition, aforementioned, while the major portion of the surface 54 functions as a guiding surface for guiding the nail into the barrel as pivotal delivery motion is imparted thereto. In practice, a chute 56 is provided beneath the surface 54 in a position to receive and guide each of the nails into the barrel 32 as the nail is permitted to descend through the barrel into engagement with a workpiece, not shown.

In view of the foregoing, it is believed to be readily apparent that the nail magazine 18 serves to serially advance in single file a plurality of discrete nails with each first-in-line nail being received and supported in its pre-delivery disposition in the slot 40 by the restrainer portion 48, the inclined surface 52 and the planar surface 54. As linear motion is imparted to the shuttle 44 for advancing it in a nail delivery stroke to its nail-delivery position, the head of the nail within the cup 50, along with the uppermost portion of the shank of the nail, is advanced along a path transversely related to the longitudinal axis of the magazine. Concurrently, the lowermost portion of the shank is caused to advance in a reversed direction, as pivotal motion occurs, with a portion of the planar surface 52 acting as a fulcrum. Consequently, as the shuttle 44 approaches the nail-delivery position, during its nail delivery stroke, the first-in-line nail is displaced from its pre-delivery disposition and guided, as it moves into the barrel 32, by the surface 54 whereupon the nail is caused to become coaxially aligned with the ram 14. Thus the nail is deposited within the barrel 32 in alignment with the nailing ram 14.

The gate 42 further includes a shuttle driver 58 affixed to the shuttle 44 in coaxial alignment therewith. The shuttle driver 58 includes a piston 60 seated in a suitably configured bore 62. The piston 60 includes a body 64 coupled to the shuttle 44 in a suitable manner, not illustrated. The piston 60 is provided with a head 66 across which pressure differentials are established for initiating a reciprocating motion for the piston.

The bore 62 includes a first diameter for receiving therein the body 64 of the piston, and a second diameter for receiving therein the head 66 of the piston. Thus, an annular shoulder 68 is provided within the bore, at the juncture of the portions having the different diameters. The should 68 seves as a stop shoulder for limiting axial displacement imparted to the piston 60 as the piston is advanced for advancing the shuttle 44 to its nail-receiving position.

The piston 60 continuously is baised toward a rest position whereby the shuttle 44 continuously is biased toward its nail-receiving position, by a compression spring 70. This spring is seated within the bore 62 and supported by a cover plate, not designated, fixed to the base block 38. Rest position for the piston is that in which the shuttle 44 is in its nail-receiving position. Displacement of the shuttle 44 to its nail-delivery position is effected in response to the establishment of a pressure differential across the head 66 through an introduction of a pneumatic fluid, such as compressed air, delivered to the bore 62 via a pneumatic conduit 72. The conduit 72 extends between the bore 62 and a poppet valve 74.

In order to establish an effective seal about the head 66, a first O-ring seal 76 and a second O-ring seal 77 are provided in circumscribing relation therewith. An O-ring seal 78 circumscribes the body 64 for establishing a pneumatic seal between the adjacent surfaces of the body 64 and the bore 62 in a manner and for purposes well understood by those familiar with the design and operation of pneumatically driven pistons. It will therefore be appreciated that as pneumatic fluid is delivered to the bore 62, via the conduit 72, a pressure differential is established across the head 66 of the piston 60 so that the piston is advanced from the position illustrated in FIG. 8 to the position illustrated in FIG. 14, for thus advancing the shuttle 44 to its nail-delivery position.

In the event delivery of pneumatic fluid to the bore 62 is interrupted, the spring 70 becomes effective for driving the piston 60 from the position illustrated in FIG. 14, in a reversed direction for returning the shuttle 44 to its nail-receiving position. Thus, reciprocatory motion is imparted to the shuttle 44 for effecting a transfer of nails from the magazine 18 to the barrel 32.

An exhaust port 80, FIG. 6, communicates with the bore 62. It is here noted that the O-ring seals 76 and 77 align themselves in sealing relation with the port 80 when the shuttle 44 is in its rest position for thus sealing the port. The purpose of this arrangement will hereinafter be more fully understood. However, for the present, it suffices to understand that the exhaust port 80 is sealed, relative to the bore 62, when the head 66 of the piston 60 is seated against the annular shoulder 68 and the shuttle 44 is in a nail-receiving position.

THE NAILING RAM

The nailing ram 14 is of an elongated configuration and includes a transverse face 82 which strikes each nail head delivered to the barrel 32 with a driving force, whereby the nail is caused to penetrate a workpiece, not shown.

The ram 14 includes a head 84 connected therewith at the end thereof opposite the face 82. The head 84 is of a substantially disk-shaped configuration and includes opposed pressure faces 85a and 85b against which pressures act as pressure differentials are established thereacross for imparting motion to the ram. The head 84 is seated in a ram-actuating chamber 86 defined by a cylinder 87 closed at its uppermost end by a closure segment 88 of the housing 12 and closed at its base end by closure segment 89 of the housing.

The distal end of the cylinder 87 is provided with an annular array of fluid intake ports 90 while the base end of the cylinder 87, adjacent closure segment 89, is provided with an annular array of fluid discharge ports 92. The ports 90 serve to deliver pnuematic fluid, under pressure, to the interior of the chamber 86 whereby fluid pressures are caused to act on the face 85a of the head 84, while the ports 92 permit fluid under pressure to escape from the chamber for thereby establishing a pressure differential across the head 84. Thus a nail-driving stroke is imparted to the ram 14, whereby the ram is extended into the barrel 32 for striking a nail previously positioned therein.

Similarly, there is provided a pressure intake bore 94 extending through the closure segment 89 to communicate with the ram-actuating chamber 86 for delivering thereto fluid under pressure. Disposed in circumscribing relation with the distal end of the ported cylinder 87, in spaced relation with the fluid intake ports 90, there is provided an annular array of pressure relief ports 96 through which fluid under pressure is permitted to escape from the actuating chamber 86, as the head 84 is driven in a retracting stroke in response to the pneumatic fluid delivered to the chamber 86 via the bore 94. Therefore, it should be apparent that the retracting stroke is imparted to the ram 14 simply by introducing pneumatic fluid under pressure through the bore 94, while accommodating a discharge of pressure through the ports 96. Of course, as the head 84 approaches its seated position, air is permitted to escape from the upper end of the chamber 86 via the intake ports 90, whereby seating of the head is accommodated.

In view of the foregoing, it should be apparent that the ram 14 is driven in a nailing stroke in response to delivery of fluid under pressure to the chamber 86 through the ports 90 and advanced in a retracting stroke in response to a delivery of fluid under pressure to the chamber 86, via the pressure intake bore 94.

The closure segment 88 is suitably machined to provide a relief for receiving therein an annular seal 98. This seal includes a suitable groove formed therein for receiving the distal end of the cylinder 87. The closure segment 89 is suitably machined to receive therein the base end of the cylinder 87 whereby the cylinder is supported against displacement by the closure segments 88 and 89.

Also, seated within the closure segment 89 there is provided a block 99, spaced from the bore 94, as best illustrated in FIG. 6, formed of a suitable material, such as Neoprene having a bore formed therein, not designated, through which extends the ram 14. This block 99 extends axially into the ram-actuating chamber 86 a distance such that the projected transverse surface thereof serves as a stop for the head 84 as the ram 14 approaches the extremity of its nail-driving stroke.

Concentrically related to the cylinder 87, there is a sleeve valve 100 of a cylindrical configuration. The sleeve valve 100 is interposed between the cylinder 87 and a pressure chamber 102 which circumscribes the distal end portion of the cylinder 87. The sleeve valve 100 is supported for axial reciprocation between a valve-closed position and a valve-open condition and controls the delivery of pneumatic fluid under pressure to the ram-actuating chamber 86 via fluid intake ports 90.

The peripheral portion of the seal 98 serves as a seat against which the sleeve valve 100 rests for establishing a pneumatic seal therebetween when the sleeve valve is in a valve-closed position. An O-ring 104 is seated in the housing 12, in circumscribing relation with the sleeve valve 100, for establishing a pneumatic seal between the housing and the sleeve valve adjacent to the pressure chamber 102 for thus isolating the lower portions of the sleeve valve from the pressure chamber. Thus the cylinder 87 is isolated from the pressure chamber 102 when the sleeve valve 100 is seated in a valve-closed disposition against the seal 98. Similarly, once the sleeve valve 100 is displaced in a direction toward its valve-open position, the pressure chamber 102 is caused to communicate with the ram-actuating chamber 86 through the fluid intake ports 90.

The sleeve valve 100 also is provided with a circumscribing shoulder 105 having faces 106 and 108. The face 106 is radially extended and is directed toward the closure segment 89 of the housing 12 while the face 108 is directed toward the closure segment 88 of the housing. The faces 106 and 108 are disposed at opposite sides of the plane of the O-ring 104 so that a pneumatic seal is established between the faces of the shoulder 105. Moreover, it is important here to note, that the face 106 has a greater surface area, in a radial direction, than the face 108. Opposite the face 106 there is disposed an annular shoulder 110 machined or otherwise suitably formed in the housing 12. The adjacent faces of the annular shoulder 110 and the shoulder 105 serve as the opposite ends for an annular pressure chamber 112 having a variable axial dimension. The axial dimension of the chamber is maximized when the sleeve valve 100 is seated against the seal 98, and minimized when the face 106 of the shoulder 105 engages the face of the shoulder 110.

In order to maintain the sleeve valve 100 in a seated relationship relative to the seal 98, there is provided a first pressure conduit 114, FIGS. 9 and 11, extending from the pressure chamber 102 into a fluid valving chamber 116. A second pressure conduit 118 extends from the fluid valving chamber 116 to the annular pressure chamber 112. Thus, the annular pressure chamber 112 is permitted to communicate with the pressure chamber 102, via the pressure conduits 114 and 118 and the fluid valving chamber 116. Since the effective surface area of the face 106 is greater than the effective surface of the face 108, the resulting forces applied to the sleeve valve 100, in a direction such that the sleeve valve 100 is urged to a valve-closed position, is greater than the opposing forces. Thus the sleeve valve 100 is continuously urged toward its valve-closed position.

In order to urge the sleeve valve 100 toward its valve-opened position, it is necessary to terminate the communication of the chambers 102 and 112 and to vent the chamber 112 to atmosphere in order to eliminate back pressure as the face 106 approaches the shoulder 110. This result is achieved through a pilot valve 120 seated for axial reciprocation within the valving chamber 116.

The pilot valve 120 includes a head 121 terminating in an annular face of a frusto-conical configuration, designated 122. Circumscribing the adjacent end of the first pressure conduit 114, there is an annular seat 124 configured to mate with the face 122, whereby a pneumatic seal is established therebetween as the head 121 is displaced in an axial direction toward the first conduit 114.

It is important here to note that the diameter of the head 121 is substantially less than the diameter of the valving chamber 116 so that the second pressure conduit 118 is in continuous communication with the fluid valving chamber 116. As best illustrated in FIG. 10, the head 121 of the pilot valve 120 further includes an annular face 126, in spaced relation with the face 122. The face 126 is adapted to engage on an annular seat 128, for establishing a pneumatic seal therebetween when the head 121 is unseated with respect to seat 124. Similarly, the face 126 is unseated with respect to the seat 128 when the face 122 of the head 121 is caused to engage the seat 124. Furthermore, the valving chamber 116 is provided with a relief port 130 axially spaced from the seat 128. The relationship of the head 121 and the relief port 130 is such that communication between the second pressure conduit 118 and the relief port 130 is interrupted when the face 126 of the head 121 engages against the annular seat 128. It should therefore be apparent that so long as communication is established between the pressure conduits 114 and 118, the head 121 isolates the annular chamber 112 from the relief port 130. However, once the head 121 is caused to seat against the seat 124, the face 126 disengages the seat 128 for thus permitting the pressure conduit 118 to communicate with the relief port 130, for thus venting the annular chamber 112 to atmosphere. Of course, in response to a venting of the chamber 112 to atmosphere, the pressure acting on the face 108 of the shoulder 105 causes the sleeve valve 100 to be displaced toward its valve-open position, whereby the fluid confined within the pressure chamber 102 is delivered to the ram-actuating chamber 86 through the fluid intake ports 90.

In order to facilitate a discharge of pressurized fluid from the ram-actuating chamber 86, through the fluid discharge ports 92 and the pressure relief ports 96, there is provided within the housing 12 an exhaust slot 132 through which fluid is permitted to escape from the housing 12 as the ram 14 is caused to reciprocate. The exhaust slot 132 communicates with an exhaust groove 134 circumscribing the internal surface of the sleeve valve 100 through an annular array of exhaust ports 136. It will therefore be appreciated that as pressurized fluid is discharged from the ram-actuating chamber 86, it is vented to atmosphere through the exhaust ports 136, formed in the exhaust groove 134.

In order to assure that pneumatic fluid delivered to the ram-actuating chamber 86, through the fluid-intake ports 90 or, alternatively, through the pressure intake bore 94, does not inadvertently escape through the exhaust ports 136, there is provided an annular shoulder 138 projected from the ported cylinder 87 in a radial plane intersecting the exhaust groove 134. At each of the oppositely directed, radially extended faces of the shoulder 138 there is seated a chevron seal, designated 140a and 140b, positioned to engage opposed radial surfaces of the exhaust groove 134 when the sleeve valve 100 is advanced to its valve-closed and valve-open positions.

Therefore, when the sleeve valve 100 is seated in its valve-closed position, commmunication between the fluid discharge ports 92 and the exhaust ports 136 is interrupted by the chevron seal 140a seated in one face of the shoulder 138, engaging the internal surface of the sleeve valve 100. Of course, when the sleeve valve 100 is seated in its valve-closed position, communication between the pressure relief ports 96 and the exhaust ports 136 is facilitated by the exhaust groove 134. Hence, the ram 14 may be advanced towards its retracted position without developing a substantial back pressure within the ram-actuating chamber 86.

Conversely, when the valve sleeve 100 is seated in its valve-open position, the fluid discharge ports 92 communicate with the exhaust ports 136 so that pressures within the ramactuating chamber 86 are relieved as the ram is advanced in a nailing stroke. Of course, communication between the pressure relief ports 96 and the exhaust ports 136 is interrupted by the chevron seal 140b projected into engagement with the opposed surface of the sleeve valve 100, so that pressure acting against the pressure face 85a of the head 84 of the ram 14 is not lost, via the pressure relief ports 96 and the exhaust ports 136. Accordingly, it should be apparent that the opposite ends of the ram-actuating chamber 86 are alternately caused to communicate with the exhaust slot 132 via the exhaust ports 136 formed in the exhaust groove 134 as reciprocating motion is imparted to the ram 14, for thus relieving back pressure within the ram-actuating chamber.

CONTROL CIRCUIT

It is here noted that the housing 12 includes a hollow handle 142 projected therefrom in a position to be grasped by an operator for facilitating the operation of the nailing device 10. Additionally, it should be noted that the pressure chamber 102 extends throughout the interior of the hollow handle 142. Moreover, it is believed important to note that the handle 142 includes a fitting 144 adapted to be connected with a pneumatic fluid supply line, whereby the pressure chamber 102 continuously is pressurized through a delivery of fluid under pressure, via the fitting 144.

Within the handle 142, there is disposed a flexible tubing 146, FIG. 11, including at suitable locations a plurality of poppet valves 148. These valves communicate with the pressure chamber 102 and, when opened, serve to deliver pneumatic fluid under pressure to the flexible tubing 146.

The tubing 146, in turn, terminates in a bore 150, FIG. 7, which extends downwardly into the closure segment 89 of the housing 12 and terminates within the valving chamber 152 formed in the closure segment. Within the chamber 152 there is seated the poppet valve 74. The poppet valve 74, when opened, serves to establish communication between the bore 150 and the pneumatic conduit 72, which, as aforementioned, serves to deliver fluid under pressure to the bore 62 within which is seated the shuttle driver 58.

The poppet valve 74 includes a valve head 154, FIG. 7, coaxially aligned with a valve seat 156 and is further provided with a compression spring 158 which serves to urge the valve head into a seated relationship with the valve seat 156.

In order to unseat the head 154 and thus open the poppet valve 74, there is provided an axially displaceable leg 160 which terminates in a valve lifter 162 projected into the valving chamber 152 into coaxial alignment with the valve head 154. The valve lifter 162, when advanced a predetermined distance into the chamber 152, acts against the head 154 and serves to unseat the valve head, relative to the valve seat 156, against the applied forces of the compression spring 158. Thus, the poppet valve 74 is opened for establishing communication between the bore 150 and pneumatic conduit 72.

In order to reseat the leg 160, whereby a reseating of the head is facilitated, there is provided a compression spring 163 circumscribing a valve lifter 162, externally of the valving chamber 152, and acting to urge the leg 160 toward its initial position. Of course, once the spring 158 is permitted to reseat the valve head 154 communication between the pneumatic conduit 72 and the bore 150 is interrupted. The valve lifter 162 includes an exhaust bore 164 through which the bore 62 is vented to atmosphere via the conduit 72.

The leg 160 is provided with a slotted opening 166 within which there is seated a guide screw 167, which is, in turn, threaded into a bore, not designated, provided in the nosepiece 16 immediately adjacent the barrel 32. Moreover, the length of the leg 160 is such that it extends beyond the distal end of the barrel 32 a distance sufficient to engage a workpiece as the nailing device 10 is brought into an operative disposition relative thereto. This engagement of the leg with the workpiece serves to retract the leg 160, against the applied forces of the spring 163, for thus advancing the valve lifter 162 relative to the valve head 154. Accordingly, it is to be understood that until the leg 160 is caused to engage a workpiece, the nailing device 10 is rendered inoperative, since a communication between a pneumatic conduit 72 and the bore 150 remains interrupted by the valve head 154 as it remains seated on the seat 156.

From the bore 62 there is extended a discharge bore 168. Within the distal end of the discharge bore 168 there is seated a pneumatic fitting 170 to which there is attached a flexible conduit 172. The conduit 172 extends to a fitting 174, FIG. 11, seated in the housing 12 and communicating with the valving chamber 116.

Within the valving chamber 116 there is disposed a valve actuator 176. The actuator 176 includes a piston head 178 and a stem 179 projected from the head into a coupled relation with head 121. A suitable O-ring 180 is seated in an annular groove circumscribing the head 178 of the valve actuator for thus establishing a pneumatic seal between the head and the adjacent cylindrical surface of the fluid of the valving chamber 116. It is to be understood that the fitting 174 is so related to the chamber 116 that the conduit 172 serves to deliver fluid under pressure into the valving chamber 116, immediately behind the head 178, for advancing the head 121 of the pilot valve 120 into a seated relation relative to the valve seat 124 adjacent to the end of the first pressure conduit 114.

Of course, once the poppet valve 74 is opened fluid under pressure is delivered to the bore 62, for driving the piston 60 to the extremity of its stroke. Communication is then established between the bore 62 and the valving chamber 116, through the conduit 172, for causing the head 121 to seat relative to the face 122. Thus communication between the pressure chamber 102 and the annular chamber 112 is interrupted, while communication between the annular chamber 112 and the relief port 130 is established through the second pressure conduit 118. Thus, a pressure differential is established across the shoulder 105 and displacement of the sleeve valve 100 toward its valve-open position is initiated. In response to this displacement of the sleeve valve, a nailing stroke of the ram 14 ia initiated for causing the face 82 to strike the head of a nail positioned within the barrel 32.

In order to retract the nailing ram 14, following its nailing stroke, there is provided within the housing 12 a conduit 182, FIG. 6, which extends from the pressure chamber 102 to a pressure bore 183, disposed in communication with the valve cavity 184. The cavity 184 is formed in the housing 12 and is of a disk-shaped configuration. A concentric valve seat 185 is provided within the cavity in circumscribing relation with the pressure exit of the bore 183.

Within the valve cavity 184 there is seated a disk-shaped diaphragm 186 which includes an axially extended valve head 188 having an axial bore 189 and a tapered face, not designated, configured to be received within the valve seat 185 for closing the pressure bore 183. The diagragm 186 is formed of a flexible material, such as Neoprene, and the like, which permits the diaphragm to be displaced in the presence of a pressure differential established thereacross. Additionally, the cavity is so configured as to include an annular shoulder 190 for engaging and supporting the periphery of the diaphragm against axial displacement, while the center portion thereof is free to move in axial directions for moving the valve head 188 relative to the seat 185. It will therefore be understood that so long as the head 188 remains in spaced relation with the valve seat 185, the pressure chamber 102 communicates with the ram-actuating chamber 86, at the lower portion thereof. However, once the valve head 188 is caused to engage the seat 185, the one end of the pressure intake bore 94 is effectively sealed for thus interrupting communication between the pressure chamber 102 and the actuating chamber 86. Movement of the head 188 into a seated relationship with the valve seat 185 is accomplished in response to pressure leaked from the pressure bore 183 through the axial bore 189 and trapped between the exhaust port 80 and the diaphragm. This leaked pressure acts against a greater effective surface area of the diaphragm than the pressure at the opposite side thereof so that once the pressures at opposite sides of the diaphragm are equalized, the diaphragm is caused to flex for moving the valve head 188 into a seated relationship with the valve seat 185.

In its normal position, the valve head 188 of the diaphragm 186 remains in a seated relationship with the seat 185. The bleeder port 80 is so situated as to be disposed midway between the O-rings 76 and 77 mounted on the head 66 of the piston 60 once the shuttle 44 is in a rest condition. Thus the bleeder port 80 is sealed. However, once the piston 60 has been advanced against the applied forces of the spring 70, the pressure trapped within the valve cavity 184 is confined within a plenum chamber, designated 196, defined by the diaphragm and the walls of that portion of the valve cavity 184, which communicates with the port 80. Consequently, once the bore 62 is vented to atmosphere via the conduit 72 and the bore 164, the pressure within the plenum chamber 196 is relieved to atmosphere via the bleeder port 80, the bore 62, the conduit 72, and the bore 164. Therefore, once the pneumatic conduit 72 is placed in communication with the plenum chamber and atmosphere, via the bore 164, pressure is reduced within the plenum chamber and; the valve head 188 is moved in an axial direction and caused to disengage the valve seat 185 for thus establishing communication between the pressure bore 183 and the pressure intake bore 94.

Conversely, once the shuttle 44 is seated in its rest position, communication between the valve cavity 184 and the pneumatic conduit 72 is interrupted by the head 66 of the piston 60, whereby pressure within the pressure chamber 102 serves to displace the diaphragm 186 into its normal position as the plenum chamber 196 is charged via the axial bore 189. Thus, communication between the pressure chamber 102 and the bore 94 is interrupted.

OPERATION

It is believed that in view of the foregoing description, the operation of the device will readily be understood and it will be briefly reviewed at this point.

With nailing device 10 assembled in the manner hereinbefore described and connected with a pressurized source of pneumatic fluid, at the fitting 144, the device is prepared for operation.

The nail magazine 18 is filled with a plurality of discrete nails arranged in single file and suspended between the rails 20. This, in practice, is achieved simply by coupling the distal end of the magazine 18 with a suitable nail distributing device, such as that disclosed in applicant's copending application Ser. No. 450,656. Thus a plurality of discrete nails are delivered to the magazine with the leading nail being engaged by the gate 42, in a manner such that it is received within the relief 40 and the cup 50 of the shuttle 44.

It is to be understood that the device 10 can readily be activated for rapidly driving discrete nails, serially supplied thereto by the nail magazine 18, simply by pressing a selected one of the trigger levers illustrated while substantially simultaneously therewith placing the leg 160 against a selected workpiece. As the selected lever is depressed, the associated poppet valve 148 delivers pneumatic fluid under pressure from the pressure chamber 102 to the bore 150, via the flexible tubing 146. Of course, once the leg 160 has been placed against a piece of work, the valve head 154 of the poppet valve 74 is unseated, relative to the valve seat 156, so that the bore 150 is thus placed in communication with the bore 62 within which is seated the piston 60. The piston 60 is responsively moved in an axial direction against the applied forces of the compression spring 70 for axially displacing the shuttle 44.

In response to a displacement of the shuttle 44 the head portion of the nail previously seated within the cup 50 is advanced laterally for causing the nail to, in effect, pivot and drop vertically into the barrel 32 and thus become axially aligned with the nailing ram 14. Thus the nail is extracted from the magazine 18. It is here noted that the nail restrainer portion 48 serves to restrain the file of discrete nails from advancing until the shuttle 44 is returned to its rest position, while the chute 56 serves to assure that the extracted nail properly enters the barrel 32 as it drops into the bore of the barrel 32.

The discharge bore 168 is placed in communication with the pneumatic conduit 72 in response to the axial displacement imparted to the piston 60 for delivering the nail to the barrel 32. Pneumatic fluid is now delivered to the fluid valving chamber 116, via the conduit 172. As the fluid is delivered to the valving chamber 116, the head 178 of the valve actuator 176 is responsively displaced in an axial direction, in response to a pressure differential established across the head. Axial displacement of the head causes the face 122 of the head 121 to seat against the face of the valve seat 124 for interrupting communication between the chamber 102 and the pressure chamber 112, while simultaneously permitting the pressure chamber to communicate with atmosphere, via the relief port 130.

Consequently, the pressure of the fluid confined within the pressure chamber 102, acting on the face of the face 108, of the shoulder 105 causes the sleeve valve 100 to move in an axial direction for placing the fluid intake ports 90 of the ramactuating chamber 86 in communication with the pressure chamber 102. Concurrently, with the opening of the fluid intake ports 90, thus effected, the fluid discharge ports 92 are placed in direct communication with the exhaust ports 136 formed in the exhaust groove 134, whereby a pressure differential in fluid pressures acting against the faces 85a and 85b of the head 84 of the ram 14 is established. In response to the pressure differential thus established, the ram 14 is rapidly advanced in a nailing stroke axially into the barrel 32 so that the head of the nail positioned therein is struck a sharp blow by the face 82 of the ram. Thus, the nail is caused to penetrate the workpiece.

In order to retract the ram 14 to thus complete a cycle of operation as the ram 14 is returned to its initial position, the device 10 is lifted out of engagement with the workpiece. The delivery of fluid under pressure, from the bore 150 to the bore 62, is thus interrupted by a reseating of the valve head 154, as the leg 160 disengages the workpiece and is again extended in response to the applied forces of the spring 163. Thus, delivery of pneumatic fluid to the bore 62, via the pneumatic conduit 72 is interrupted so that the spring 70 now urges the piston 60 to its rest position. The piston 60 cannot now return to its rest position, however, due to the presence of the ram 14 within the cup 50. The plenum chamber 196 is bled to ambient atmosphere via the bleeder port 80, the bore 62, the conduit 72 and the bore 164 whereupon the diaphragm 186 is flexed for withdrawing the head 188 from engagement with the seat 185 so that the pressure bore 183 now is caused to communicate with the ram-actuating chamber 86, via the pressure intake bore 94. Simultaneously, the discharge bore 168 is caused to communicate with ambient atmospheric pressure, via the bore 164, so that valving chamber 116 also is vented to atmosphere via the conduit 172. Thus the pilot valve 120 is caused to open, as the head 121 is forced out of a seated relationship with the seat 124, by the applied pressures of the fluid within the chamber 102.

In response to the opening of the pilot valve 120, the expansible annular chamber 112 again is placed in communication with the pressure chamber 102. Due to the difference in surface areas of the faces 106 and 108, the sleeve valve 100 is advanced towards its initial position for thus isolating the fluid intake ports 90 from the pressure chamber 102. Fluid under pressure is now delivered to the ram-actuating chamber 86 from the chamber 102, via the bore 183 and the bore 94. This fluid acts on the face 85b of the head 84 and serves to drive the ram 14 upwardly, as shown, towards its initial or rest position. Thus a cycle of operation is completed.

It will be appreciated that as the sleeve valve 100 returns to its initial position, the fluid intake ports 90 and the pressure relief ports 96 are placed in communication with the exhaust ports 136 for thus eliminating back pressure as the head 84 is advanced and seated during the retraction stroke of the ram 14. Of course, once the sleeve valve 100 seats in its initial or valve-closed position, a pneumatic seal is established between the valve sleeve and the cylinder 87, by the chevron seal 140a, for thus isolating the fluid discharge ports 92 from the exhaust groove 134.

Moreover, once the ram 14 is retracted from cup 50 the compression spring 70 causes the piston 60 to seat in its rest position, so that communication between the conduit 72 and the plenum chamber 196 is interrupted by the O-rings 76 and 77. Hence, the pressure of the pneumatic fluid confined within the chamber 102 charges the plenum chamber 196, via the opening in the diaphragm 186, for again causing the head 188 to engage the seat 185 for terminating the flow of fluid from the chamber 102 to the ram-actuating chamber 86 via the bore 94.

It should be apparent that various sources of compressed air may be employed in actuating the nailing device 10. However, in practice, a suitable compressor is connected with the device 10 to communicate with the chamber 102 through the fitting 144, preferably through a suitable flexible conduit.

In view of the foregoing, it should readily be apparent that the device of the instant invention provides a practical solution to the perplexing problem of providing an automatic device for use in driving discrete headed objects serially delivered from a magazine adapted to be resupplied readily and easily with minimal effort and loss of time.

Although the invention has been herein shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of the invention, which is not to be limited to the illustrative details disclosed.

Claims

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

1. A pneumatic device for driving a headed object having a head and an elongated shank extended therefrom comprising:

A. a driver housing;

B. a cyclically operable ram supported within said housing for axial displacement along a rectilinear path and characterized by means including at one end thereof a face for striking the head of a headed object positioned within said path; and

C. object feeding means mounted on said housing adapted to position a headed object within the path of the ram including,

1. retainer means disposed adjacent to said rectilinear path for supporting said object in a pre-delivery disposition relative to said path with the shank thereof being extended through a reference plane intersecting the longitudinal axis of symmetry for said path, along the length thereof,

2. means including a barrel having an axial bore concentrically related to the path of said ram for receiving said headed object, and

3. means for delivering said headed object from said retainer means to said bore.

2. The device of claim 1 wherein said retainer means includes:

A. means defining within said barrel, at one side of said reference plane, an elongated opening having a first planar surface extended in a plane intersecting the reference plane along a line of intersection paralleling the longitudinal axis of the rectilinear path for engaging an extended end portion of said object as it is extended through said reference plane; and

B. means defining within said barrel, at the opposite side of said reference plane, another opening including a second planar surface inclined with respect to the longitudinal axis of the barrel and passing through the bore between the opposite end portions thereof for supporting the opposite end portion of said object.

3. The device of claim 2 wherein said means for delivering said headed object from said retainer means to said bore comprises:

means for pivotally displacing said object about a fulcrum defined by a surface coincident with the line of intersection of said second planar surface with said bore.

4. The device of claim 3 wherein said means for pivotally displacing said object includes a cyclically operable shuttle supported for sequential displacement in an article delivery stroke and a shuttle-return stroke along a rectilinear path transversely related to said reference plane.

5. The device of claim 4 wherein said means for delivering said headed objects further comprises:

means for imparting an article delivery stroke to said shuttle including an actuator responsive to a delivery of fluid under pressure thereto, and a fluid delivery circuit connected with the actuator for selectively delivering fluid under pressure to the actuator.

6. A pneumatic device particularly adapted for driving headed objects comprising:

A. a housing;

B. an elongated cylinder disposed within said housing;

C. means within said housing including a fluid reservoir for confining fluid under pressure greater than one atmosphere;

D. a ram having a head of a disk-shaped configuration and an elongated driving body projected axially from the head and supported for axial displacement in driving and retraction strokes within said cylinder along a path coaxially aligned therewith;

E. ram-actuating means including a cyclically operable sleeve of a cylindrical configuration concentrically related to said cylinder and communicating with said reservoir supported for axial displacement along a rectilinear path extended between a valve-open position and a valve-close position for alternately establishing pressure differentials across said head;

F. feeder means mounted on said body for serially aligning within the path of said driving body a plurality of elongated objects including,

1. a gravity-fed magazine adapted to advance a file of discrete, gravitating objects along a linear path extended toward the path of said ram,

2. gate means interposed between said gravity-fed magazine and said ram for serially extracting objects from said file including a cyclically operable shuttle supported for sequential displacement in an article delivery stroke and a shuttle return stroke along a rectilinear path,

3. means for imparting to said shuttle an article delivery stroke characterized by a piston supported for axial displacement in response to fluid delivered under pressure to said actuator for imparting an object delivery stroke to said shuttle,

4. a fluid delivery circuit connected with said ram actuating means including a manually operable trigger valve communicating with said reservoir, a poppet valve interposed in said circuit between said trigger valve and said ram actuating means, means adapted to engage a piece of work for opening said poppet valve and a pilot valve interposed between said ram actuating means and said sleeve valve responsive to an axial displacement of said piston, as the piston imparts an article delivery stroke to said shuttle, for initiating driving stroke for said ram.

7. The device of claim 6 wherein said feeder means further includes retainer means for supporting each first-in-line object of said file of discrete objects in an inclined disposition relative to a reference plane intersecting the path of said driving body along the full length thereof.

8. In a pneumatic device for driving elongated objects, the improvement comprising:

A. a portable housing;

B. a tubular body of a cylindrical configuration disposed within said housing;

C. means including within said housing a fluid reservoir for confining fluid under pressure greater than one atmosphere;

D. a ram having a head of a disk-shaped configuration and an elongated driving body projected axially from the head disposed within said tubular body and supported for sequential displacement in object driving and ram return strokes; and

E. ram actuating means for cyclically establishing alternating pressure differentials across said head including a cyclically operable sleeve valve concentrically related to said tubular body supported for rectilinear displacement between a valve-open position and a valve-close position for alternately venting each of the opposite ends of said tubular body to atmosphere.

9. A pneumatic device comprising:

A. a portable housing;

B. means defining within the housing an elongated cylinder;

C. means defining within said housing a fluid reservoir for confining fluid under pressure greater than one atmosphere;

D. a ram having a head of a disk-shaped configuration and a driving body projected axially from the head and supported for reciprocation within said cylinder;

E. feeder means mounted on said housing for serially aligning within the path of said driving body a plurality of elongated objects including a gravity-fed magazine adapted to advance a file of gravitating, discrete objects along a linear path toward said housing, a guide of a tubular configuration coaxially aligned with said driving body and disposed in an offset relation with the magazine, gate means for serially extracting objects from said file, including a transfer shuttle supported by said housing for rectilinear motion along a linear path substantially orthogonally related to the path of the objects of said file, a cylindrical bore extended into said housing adjacent to said shuttle, means connected with said reservoir for delivering pressurized fluid to said bore, and a pressure-actuated piston seated in said bore and connected with said shuttle for imparting linear motion to the rack in response to a delivery of pressurized fluid to said bore;

F. ram-actuating means including a cyclically operable sleeve valve concentrically related to said cylinder and communicating with said reservoir supported for displacement between a valve-open position and a valve-close position for alternately establishing pressure differentials across said head, including a body of a cylindrical configuration having a radially projected shoulder circumscribing the body and having a first annular face characterized by a first surface area continuously communicating with said reservoir, whereby the valve body is continuously urged in displacement toward said valve-open position, and a second annular face characterized by a second surface area greater than said first surface area intermittently communicating with said reservoir for intermittently urging said body in displacement toward said valve-close position, and means for interrupting communication between said second annular face and said reservoir, including a pilot valve connected with said bore; and

G. manually operable trigger means including a length of flexible tubing extended through said reservoir and having a first poppet valve interposed within said length of tubing, characterized by an actuating stem projected from said handle, a second poppet valve connected with said conduit in circuit series with said bore, and means including a work engaging leg supported for axial displacement relative to said second poppet valve for actuating the second poppet valve in response to an engagement of the leg with a selected piece of work for establishing a fluid path between said first poppet valve and said bore.

10. The pneumatic device of claim 9 wherein said ram actuating means further includes:

a fluid delivery circuit for intermittently delivering fluid under pressure to one end of said tubular body including a conduit extended between said reservoir and said tubular body, means defining a cavity within said conduit, and pressure responsive valve means disposed within said cavity comprising a flexible diaphragm supported for valve-actuating displacement in axial directions characterized by a pair of opposite faces having unequal surface areas, and means for axially displacing said diaphragm including a bore extended axially through said diaphragm for establishing thereacross zero pressure differentials.