Magazine assembly for fastening tool

A magazine assembly for a fastening tool. The magazine assembly slides on guide posts that are formed into the nose assembly of the fastening tool and is clamped to the fastening tool via a magazine clamp assembly that requires no tools to operate. The magazine clamp assembly may be partially released to permit the magazine assembly to be partially withdrawn from the nose assembly so that the nose assembly may be maintained without the complete removal of the magazine assembly. The construction of the nose assembly is such that when the magazine assembly is placed in a partially withdrawn state, a portion of the nose assembly mechanically inhibits actuation of the fastening tool trigger system.

 

1. A fastening tool for holding a plurality of fasteners and selectively installing a first one of the fasteners into a workpiece, the fastening tool comprising:

a fastening tool portion having a dispensing portion for dispensing the first one of the fasteners;

a magazine assembly;

a guide post coupled to one of the fastening tool portion and the magazine assembly;

a guide portion formed in the other one of the fastening tool portion and the magazine assembly, the guide portion including a guide port slidingly receiving; and

a clamp for releasably securing the magazine assembly to the fastening tool portion, the clamp including a track that is associated with the magazine assembly, the clamp further including a follower member that is carried by the fastening tool portion and slidably disposed in the track;

wherein the magazine assembly is movable between a predetermined first position in which the magazine assembly is proximate the dispensing portion so that fasteners can be fed from the magazine assembly into the dispensing portion and a predetermined second position in which the magazine assembly is spaced apart from the dispensing portion; and

wherein the guide post is received in the guide port in the first position and the second position and wherein the first and second positions are defined by contact between the follower and two segments of the track that are configured to restrict further movement of the follower.

2. The fastening tool of claim 1, wherein the two segments of the track are configured to restrict further movement of the follower along an axis that is generally parallel to a direction in which the fasteners are fed into the dispensing portion.

3. The fastening tool of claim 1, wherein at least one of the two segments is an end segment of the track.

4. The fastening tool of claim 3, wherein another one of the two segments is positioned at an intermediate position along a length of the track and wherein the guide post is decoupled from the guide port when the follower is positioned at a third segment of the track.

5. The fastening tool of claim 4, wherein each of the segments of the track is aligned along a common axis that is generally parallel to a direction in which the fasteners are fed into the dispensing portion.

6. A fastening tool comprising:

a fastening tool portion having a dispensing portion, the dispensing portion including a nosepiece and a contact trip that is slidably coupled to the nosepiece, the nosepiece defining a lock-out aperture; and

a magazine assembly coupled to the fastening tool portion, the magazine assembly having a magazine housing and a follower body, the magazine housing being adapted for holding a plurality of fasteners, the follower body being at least partially received in the magazine housing and movable thereto so as to urge the fasteners toward the dispensing portion, the follower body including a lock-out dog that extends into the lock-out aperture to block movement of the contact trip and thereby inhibit the operation of the fastening tool portion when the magazine assembly is positioned in a condition which permits fasteners to be fed into the dispensing portion and a quantity of fasteners in the magazine assembly is less than a predetermined quantity.

7. The fastening tool of claim 6, wherein the nosepiece includes a magazine flange against which the magazine assembly is abutted.

8. The fastening tool of claim 6, wherein the magazine assembly is positionable relative to the fastening tool portion in a first position wherein the magazine assembly is abutted against the nosepiece, and a second position wherein the magazine assembly is spaced apart from the nosepiece.

9. The fastening tool of claim 8, wherein the follower body is biased toward a dispensing end of the magazine housing and wherein the magazine assembly includes a latch that may be selectively employed to retain the follower body at an end of the magazine housing opposite the dispensing end.

10. The fastening tool of claim 6, wherein the lock-out dog is fixedly coupled to the follower body.

11. The fastening tool of claim 10, wherein the lock-out dog and the follower body are unitarily formed.

12. A fastening tool comprising:

a fastening tool portion having a nosepiece;

a magazine assembly coupled to the nosepiece, the magazine assembly having a magazine housing that is adapted for holding a plurality of fasteners;

a guide having a first guide portion coupled to the fastening tool portion and a second guide portion coupled to the magazine assembly, the first and second guide portions cooperating to guide the magazine housing into a position wherein fasteners are fed into the nosepiece; and

a clamp having a first clamp portion that is carried by the fastening tool portion and a second clamp portion that is carried by the magazine assembly, the first clamp portion and the second clamp portion cooperating to releasably couple the magazine assembly to the fastening tool portion;

wherein the guide is operable for guiding the magazine assembly in a direction that is generally parallel to a feed direction along which fasteners are dispensed from the magazine assembly into the nosepiece;

wherein the first and second clamp portions may be positioned in a first condition in which the magazine assembly is secured to the fastening tool in a manner that permits fasteners to be dispensed from the magazine housing into the nosepiece, and wherein the first and second clamp portions may be positioned in a second condition in which the magazine assembly is spaced apart from the nosepiece in a direction opposite the feed direction, the second condition being defined by at least one of the first and second clamp portions so as to inhibit further movement of the magazine assembly in the direction opposite the feed direction; and

wherein the first guide portion and the second guide portion are engaged to one another when the first and second clamp portions are in the second condition.

13. The fastening tool of claim 12, wherein one of the first clamp portion and the second clamp portion includes a pin and the other one of the first clamp portion and the second clamp portion includes a bracket with a slot formed therethrough and wherein the pin is received in the slot when the first clamp portion and the second clamp portion are in the first and second conditions.

14. The fastening tool of claim 12, wherein one of the first guide portion and the second guide portion includes a post and wherein the other one of the first guide portion and the second guide portion includes an aperture into which the post may be received.

15. The fastening tool of claim 14, wherein the magazine housing includes a slotted aperture having a first portion that extends generally parallel to the feed direction and a second portion that extends in a second direction, and wherein the fastening tool portion includes a contact trip having a stop member that is disposed in the slotted aperture, the stop member being configured to traverse in the second portion of the slotted aperture in the magazine housing when the first and second clamp portions are positioned in the first position, and wherein the first portion of the slotted aperture in the magazine housing is configured to confine the stop member when the first and second clamp members are in the second condition to thereby inhibit the contact trip from moving to an activated condition that enables the operation of the fastening tool portion.

16. The fastening tool of claim 15, wherein slotted aperture in the magazine housing is generally L-shaped.

17. A fastening tool comprising:

a fastening tool portion having a nosepiece;

a magazine assembly coupled to the nosepiece, the magazine assembly having a magazine housing that is adapted for holding a plurality of fasteners;

a guide having a first guide portion coupled to the fastening tool portion and a second guide portion coupled to the magazine assembly, the first and second guide portions cooperating to guide the magazine housing into a position wherein fasteners are fed into the nosepiece; and

a clamp having a first clamp portion that is carried by the fastening tool portion and a second clamp portion that is carried by the magazine assembly, the first clamp portion and the second clamp portion cooperating to releasably couple the magazine assembly to the fastening tool portion;

wherein the guide is operable for guiding the magazine assembly in a direction that is generally parallel to a feed direction along which fasteners are dispensed from the magazine assembly into the nosepiece;

wherein the first and second clamp portions may be positioned in a first condition in which the magazine assembly is secured to the fastening tool in a manner that permits fasteners to be dispensed from the magazine housing into the nosepiece, and wherein the first and second clamp portions may be positioned in a second condition in which the magazine assembly is spaced apart from the nosepiece in a direction opposite the feed direction;

wherein the first guide portion and the second guide portion are engaged to one another when the first and second clamp portions are in the second condition;

wherein one of the first guide portion and the second guide portion includes a post and wherein the other one of the first guide portion and the second guide portion includes an aperture into which the post may be received; and

wherein the magazine housing includes a slotted aperture having a first portion that extends generally parallel to the feed direction and a second portion that extends in a second direction, and wherein the fastening tool portion includes a contact trip having a stop member that is disposed in the slotted aperture, the stop member being configured to traverse in the second portion of the slotted aperture in the magazine housing when the first and second clamp portions are positioned in the first position, and wherein the first portion of the slotted aperture in the magazine housing is configured to confine the stop member when the first and second clamp members are in the second condition to thereby inhibit the contact trip from moving to an activated condition that enables the operation of the fastening tool portion.

18. The fastening tool of claim 17, wherein the slotted aperture in the magazine housing is generally L-shaped.

FIELD OF THE INVENTION

The present invention generally relates to a fastening tool for dispensing fasteners from a magazine assembly into a workpiece and more specifically to an improved magazine assembly for a fastening tool.

BACKGROUND OF THE INVENTION

A number of pneumatically operated devices have been developed for use in driving fasteners, such as staples and nails, into workpieces. These tools typically employ a magazine assembly for holding a plurality of the fasteners and feeding the fasteners into the nose of the tool prior to the installation of the fasteners into a workpiece.

Despite the wide spread use of such tools, several drawbacks have been noted. One such drawback concerns the dry-firing of the tool when an insufficient number of fasteners are contained in the magazine assembly. As is known in the art, the dry-firing of such tools tends to be harmful to the tool.

Another drawback relates to situations wherein one or more fasteners are jammed in the nose of the tool. In such situations, the magazine assembly is typically removed from the fastening tool so as to provide sufficient space to permit the operator to remove the jammed fasteners from the nose of the fastening tool. Often times, tools, such as pliers, are employed in this task, so that the amount of space that is required for servicing the nose of the tool can be significant. Unfortunately, the complete removal of the magazine assembly from the remainder of the tool is often times very time consuming and may also require the use of additional tools to physically disconnect the magazine assembly.

SUMMARY OF THE INVENTION

In one preferred form, the present invention provides a fastening tool for holding a plurality of fasteners and selectively setting a first one of the fasteners into a workpiece. The fastening tool includes a fastening tool portion and a magazine assembly. The fastening tool portion has a dispensing portion for dispensing a first one of the fasteners and the magazine assembly is configured to hold a portion of the fasteners. The magazine assembly is coupled to the fastening tool portion and positionable between a first position, wherein the magazine assembly is positioned to dispense the portion of fasteners into the dispensing portion, and a second position, wherein the magazine assembly is positioned so as to be incapable of dispensing the portion of the fasteners into the dispensing portion.

In another preferred form, the present invention provides a fastening tool for holding a plurality of fasteners and selectively installing a first one of the fasteners into a workpiece. The fastening tool includes a fastening tool portion having a dispensing portion for dispensing a first one of the fasteners, wherein the dispensing portion includes a lock-out aperture. The fastening tool also includes a magazine assembly for holding a portion of the fasteners. The magazine assembly, which is coupled to the fastening tool portion, includes a lock-out dog that extends into the lock-out aperture and inhibits the fastening tool portion from operating when the magazine assembly is positioned in a condition which permits the magazine assembly to feed the portion of the fasteners into the dispensing portion and a quantity of the fasteners in the magazine assembly is less than a predetermined quantity.

In yet another preferred form, the present invention provides a fastening tool for holding a plurality of fasteners and selectively installing a first one of the fasteners into a workpiece. The fastening tool includes a fastening tool portion, a magazine assembly coupled to the fastening tool portion, a guide post coupled to one of the fastening tool portion and the magazine assembly, and a guide port formed in the other one of the fastening tool portion and the magazine assembly, the guide port slidingly receiving the guide post.

Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Additional advantages and features of the present invention will become apparent from the subsequent description and the appended claims, taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a left side view of a tool constructed in accordance with the teachings of a preferred embodiment of the present invention;

FIG. 2 is a right side view of the tool of FIG. 1;

FIG. 3 is an exploded perspective view of the tool of FIG. 1;

FIG. 4 is a sectional view of the tool of FIG. 1 taken through its longitudinal axis;

FIG. 4a is a section view taken along the line 4a—4a of FIG. 4;

FIG. 5 is a top view of the tool of FIG. 1;

FIG. 6 is a sectional view taken along the line 6—6 of FIG. 5;

FIG. 7 is an enlarged portion of FIG. 4 illustrating the nose assembly in greater detail;

FIG. 8 is a front view of a portion of the tool of FIG. 1 illustrating the nose body and the contact tip in greater detail;

FIG. 9 is a sectional view taken along the line 9—9 of FIG. 2;

FIG. 9a is sectional view of a portion of the magazine clamp assembly illustrating the spring collar in greater detail;

FIG. 9b is a sectional view of a portion of the magazine clamp assembly illustrating the clamp pin in greater detail;

FIG. 10 is an enlarged portion of FIG. 4 illustrating the trigger assembly in greater detail;

FIG. 11 is an exploded view of the tool of FIG. 1;

FIG. 12 is an enlarged portion of FIG. 4 illustrating the rear of tool in greater detail;

FIG. 13 is a sectional view of a portion of the exhaust manifold illustrating the construction of the exhaust ports in greater detail;

FIG. 14 is an enlarged portion of FIG. 4 illustrating the engine assembly in greater detail;

FIG. 15 is an enlarged portion of FIG. 11 illustrating the engine assembly in greater detail;

FIG. 16 is a sectional view of the sleeve taken along its longitudinal axis;

FIG. 17 is a sectional view taken along the line 17—17 of FIG. 16;

FIG. 18 is a sectional view similar to that of FIG. 10 but illustrating the trigger assembly in an actuated condition;

FIG. 19 is an exploded perspective view of the magazine assembly;

FIG. 20 is a sectional view taken along the line 20—20 of FIG. 1 and illustrating the construction of the magazine body assembly;

FIG. 21 is a rear view of a portion of the magazine body assembly;

FIG. 22 is a side view of a portion of the magazine body assembly illustrating the L-shaped pin aperture in greater detail;

FIG. 23 is a top view of a guide structure;

FIG. 24 is a front view of the bracket structure;

FIG. 25 is a rear view of a portion of the bracket structure;

FIG. 26 is a side view of a portion of the bracket structure;

FIG. 27 is a side view of the follower structure;

FIG. 28 is a top view of a portion of the follower structure illustrating the construction of a portion of the follower body, the follower guide and the actuating lever;

FIG. 29 is a view of a portion of the follower structure illustrating the configuration of the forward leg of the follower body;

FIG. 30 is a view of a portion of the follower structure illustrating the configuration of the rearward leg of the follower body;

FIG. 31 is a front view of a portion of the follower structure;

FIG. 32 is a partial view of the follower structure from a side opposite the side which is illustrated in FIG. 27;

FIG. 33 is a side view of the follower spring;

FIG. 34 is a side view of the magazine end cap assembly;

FIG. 35 is a sectional view of a portion of the end cap structure taken along the line 35—35 in FIG. 34;

FIG. 36 is a sectional view of a portion of the end cap structure taken along the line 36—36 in FIG. 35;

FIG. 37 is a top view of a portion of the end cap structure;

FIG. 38 is a front view of the cam follower;

FIG. 39 is a partial side view of the cam follower;

FIG. 40 is an enlarged portion of the cam follower illustrated in FIG. 38;

FIG. 41 is a partial side view of the cam follower illustrating the follower hook in greater detail;

FIG. 42 is a partial section view illustrating the position of the cam follower on the pivot structure just prior to contact between the loading cam and the follower hook;

FIG. 43 is a partial section view similar to that of FIG. 42 but illustrating the cam follower when the follower hook is contacting the first loading cam portion;

FIG. 44 is a side view of the follower structure engaged to the magazine end cap assembly;

FIG. 45 is a section view taken along the line 45—45 illustrating the follower hook disposed within the capture aperture;

FIG. 46 is a side view of a portion of a tool constructed in accordance with the teachings of the an alternate embodiment of the present invention illustrating the magazine assembly removed from the tool; and

FIG. 47 is a side view similar to that of FIG. 46 but illustrating the magazine assembly coupled to the tool.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIG. 1 of the drawings, a fastening tool constructed in accordance with the teachings of the present invention is generally indicated by reference numeral 10. Fastening tool 10 is illustrated to include a detachable magazine assembly 20 and a fastening tool portion 30. The fastening tool portion 30 includes a nose assembly 40, a housing assembly 42, a cap assembly 44, an engine assembly 46 and a trigger assembly 48.

Nose Assembly

With reference to FIGS. 1 through 9, the nose assembly 40 is illustrated to include a nose structure 50, a contact trip 52, a trigger lever 54 and a contact trip-return spring 56. The nose structure 50 includes a nose body 60, a pair of magazine stabilizing tabs 62, a magazine flange 64, a pair of magazine guide posts 66, a mounting base 68, a spring post 70 and a pair of contact trip guides 72. The nose body 60 is generally U-shaped, with the legs 80 of the "U" being inwardly offset to form a semi-circular blade cavity 82. The inwardly offset legs 80 of the nose body 60 also serve as a guide surface 84 for guiding the lower front portion 86 of the contact trip 52. The contact trip guides 72 are coupled to the top of the nose body 60 and form a guide surface for guiding the portion 88 of the contact trip 52 that extends over the nose body 60.

The magazine stabilizing tabs 62 are situated on opposite sides of the nose body 60 and are spaced apart by a predetermined distance. The magazine flange 64 is a generally flat structure that is coupled to the bottom of the nose body 60 and that includes a lock-out dog aperture 90. The magazine guide posts 66, which are cylindrically shaped in the particular embodiment illustrated, extend downwardly and rearwardly from the magazine flange 64. The magazine stabilizing tabs 62, magazine flange 64 and magazine guide posts 66 are discussed in greater detail, below.

The mounting base 68 is coupled to the magazine flange 64 and the nose body 60 and includes a pair of mounting apertures 94, a nose seal groove 96 and a nose guide 98. The nose guide 98 is generally cylindrically shaped and includes an internal cavity 100 that having a cross-section that is configured to receive the fastener F and which may include a fastener stop 102 which is configured to prevent the fasteners F from traveling rearwardly toward the engine assembly 46. In the embodiment illustrated, the internal cavity 100 is generally semi-circular in shape but which includes a key-shaped fastener stop 102. The nose seal groove 96 is formed around the outer perimeter of the nose guide 98 and is sized to receive a nose seal 104, which is an O-ring seal in the particular embodiment illustrated. The spring post 70 is coupled to the top of the mounting base 68 and includes a boss 108 that is sized to fit within the contact trip-return spring 56.

The contact trip 52 is fit over and slides on the nose body 60, being guided thereon by the inwardly offset legs 80 of the nose body 60 and the contact trip guides 72. Preferably, the effective length of the contact trip 52 is adjustable so as to permit the tool operator to vary the depth at which the tool 10 sets the fasteners F. A spring protrusion 110, which is sized to engage the inside diameter of the contact trip-return spring 56, is formed in the rear of the contact trip 52. The contact trip-return spring 56 is set over the boss 108 on the spring post 70 and the spring protrusion 110 on the contact trip 52 and exerts a spring force that biases the contact trip 52 away from the spring post 70. Forward motion of the contact trip 52 is checked by a contract trip stop 114 that is formed onto a side of the nose body 60 and which contacts the contact trip 52 at a predetermined point.

The trigger lever 54 is fixedly coupled to the contact trip 52 at a first end 120 and extends rearwardly from the nose structure 50 where a second end 122 engages the trigger assembly 48 in a conventional manner that is well known in the art. Briefly, the trigger assembly 48 includes a primary trigger 126, a secondary trigger 128 and a trigger valve 130 that selectively controls the flow of compressed air to the engine assembly 46. The primary trigger 126 is pivotably mounted to the housing assembly 42 and movable in response to the tool operator's finger. Movement of the primary trigger 126 will not, in and of itself, alter the state of the trigger valve 130. Rather, the second end 122 of the trigger lever 54 must also move rearwardly and into contact with the secondary trigger 128 before the state of the trigger valve 130 is changed to permit compressed air to flow to the engine assembly 46. A stop member 134, which is configured to interact with the magazine assembly 20 in a matter that will be discussed in greater detail below, is coupled to the trigger lever 54 below the magazine flange 64 and extends inwardly toward the nose body 60. In the particular embodiment illustrated, the stop member 134 is die-punched into the trigger lever 54 and is offset inwardly therefrom toward the nose body 60.

Housing Assembly

Housing assembly 42 includes a unitarily formed housing 150, a piston bumper 152, a magazine clamp assembly 154 and a housing seal 156, which is illustrated to be an O-ring seal in the example provided. The housing 150 includes a housing body 160, a trigger housing 162, a nose housing 164 and a handle portion 166. The housing body 160 is a container-like structure having a front base 170 and an outwardly tapering sidewall 172 that cooperate to form a housing cavity 174. The outwardly tapering sidewall 172 terminates at the rear of the housing body 160 at a rear housing face 176, which in the particular embodiment illustrated, includes a housing seal groove 178 that is configured to receive the housing seal 156. A guide bore 180 is formed into the inside face 182 of the housing cavity 174 and terminates at its forward end at a guide stop 184. A nose guide aperture 188 is formed through the front base 170 of the housing body 160.

The nose housing 164 is coupled to the front base 170 of the housing body 160 and extends forwardly therefrom. The nose housing 164 includes an upper shroud 200, a pair of sidewalls 202 and a pair of spaced apart bosses 204, each of which having a threaded aperture 206. The upper shroud 200, sidewalls 202 and spaced apart bosses 204 cooperate to locate the nose assembly 40 to the housing 150 and the nose guide 98 is inserted into the nose guide aperture 188. Threaded fasteners 210 are placed through each of the mounting apertures 94 in the mounting base 68 and threadably engaged to the threaded apertures 206 in the spaced apart bosses 204 to fixedly but removably couple the nose assembly 40 to the housing 150. The axis 212 of the threaded fasteners 210 is skewed toward the rear of the tool 10, causing the threaded fasteners 210 to exert a clamping force that pushes the nose assembly 40 downwardly onto the spaced apart bosses 204 and rearwardly against the front face of the front base 170 to thereby compress the nose seal 104 and sealingly engage the nose structure 50 to the housing body 160. The upper shroud covers the spring post 70, the contact trip-return spring 56 and a portion of the rear of the contact trip 52 to prevent foreign objects from lodging between the rear of the contact trip 52 and the spring post 70.

The handle portion 166 is preferably non-circular in shape and contoured to comfortably fit the hand of a tool operator. The distal end 250 of the handle portion 166 is enlarged so as to render the handle portion 166 less prone to slipping out of the tool operator's hand. With additional reference to FIG. 4a, a clamp boss 252 is coupled to the forward face of the distal end 250 of the handle portion 166. The clamp boss 252 includes a clamp boss base 254 that extends toward the front of the tool 10, a clamp boss sidewall 256 that wraps around the perimeter of the clamp boss base 254 and an annular intermediate clamp boss wall 258 that cooperates with a portion of the clamp boss sidewall 256 to form a circular spring cavity 260. The clamp boss base 254 and the clamp boss sidewall 256 cooperate to form a clamp cavity 262 into which the magazine clamp assembly 154 is disposed. A pair of U-shaped pin apertures 264, which will be discussed in further detail below, are formed into an end of the clamp boss sidewall 256.

The handle portion 166 intersects both the housing body 160 and the trigger housing 162 and includes an air inlet cavity 270 which extends through the distal end 250 of the handle portion 166 to receive a supply of compressed air. The air inlet cavity 270 extends through the handle portion 166 and into both the housing cavity 174 and the trigger housing 162 to permit the compressed air to be directed through the tool 10 in a predetermined manner that will be described in detail, below.

In the example provided, the magazine clamp assembly 154 is illustrated to include a clamp pin 300, a compression spring 302, a spring collar 304, an actuating cam 306 and a coupling pin 308. The clamp pin 300 includes a head portion 322, a first body section 324, which is coupled to the head portion 322, and a second body section 326 that is coupled to the opposite end of the first body section 324. The first body section 324 is generally cylindrically shaped and includes a pair of parallel flats 328. The second body section 326 is generally cylindrically shaped but has an outer diameter that is smaller than that of the first body section 324. The head portion 322 includes a frusto-conical abutting face 330.

The spring collar 304 includes a first annular portion 340 having a diameter that is sized to fit within the compression spring 302, and a second annular portion 342 that is relatively larger in diameter than the compression spring 302 and which has a flat contact surface 344. A pin aperture 346 is formed through the spring collar 304 that is sized to receive the second body section 326 of the clamp pin 300.

The actuating cam 306 has a base portion 350 and a leg portion 352 which are arranged relative to one another in an L-shape. The end of the base portion 350 opposite the intersection point 354 between the base and leg portions 350 and 352 includes a coupling pin aperture (not specifically shown) which is sized to engage the coupling pin 308. The leg portion 352 of the actuating cam 306 is arcuate in shape and includes a plurality of gripping protrusions 356 or is otherwise textured on its inside surface so as to improve the tool operator's ability to move the actuating cam 306 in a desired direction. A slot 358, which is sized to engage the second body segment 326 of the clamp pin 300 in a slip-fit manner, is formed into the actuating cam 306 through the base portion 350 and a portion of the leg portion 352.

The clamp pin 300 extends through a pin aperture 360 formed into the clamp boss base 254 of the clamp boss 252 such that the second body section 326 extends into the spring cavity 260. The compression spring 302 is positioned over the second body section 326 and into the spring cavity 260. The spring collar 304 is placed over the second body section 326 such that the first annular portion 340 is disposed inside the compression spring 302. The base portion 350 of the actuating cam 306 is positioned into contact with the flat contact surface 344 such that the second body segment 326 extends into the portion of the slot 358 that is formed into the base portion 350 of the actuating cam 306. The coupling pin 308, which is a roll-pin in the example illustrated, is positioned into one of the U-shaped pin apertures 264 and driven through the base portion 350 of the actuating cam 306 and into engagement with a pin aperture 364 in the second body segment 326 of the clamp pin 300. Accordingly, the coupling pin 308 pivotably couples the actuating cam 306 to the clamp pin 300. Rotation of the actuating cam 306 about the coupling pin 308 places the intersection point 354 into contact with the flat contact surface 344, causing the spring collar 304 to compress the compression spring 302 and transmit a clamping force to the head portion 322 of the clamp pin 300. When the actuating cam 306 has been pivoted sufficiently so as to place the leg portion 352 into contact with the flat contact surface 344, the force exerted by the compression spring 302 urges the spring collar 304 against the leg portion 352 to releasably lock the actuating cam 306 in place. The clamp cavity 262 protects the actuating cam 306 from being contacted during the operation of the tool 10, thereby guarding against the inadvertent unlocking or releasing of the actuating cam 306.

In FIG. 10, the trigger housing 162 is configured to receive the trigger assembly 48 and includes a supply port 370, which is coupled to the air inlet cavity 270 to provide the trigger assembly 48 with a source of compressed air. A biasing port 372 extends from the trigger housing 162 through the guide bore 180 in the housing cavity 174 that permits the trigger assembly 48 to direct air to or exhaust air from the housing cavity 174.

As shown in FIGS. 7 and 11, the piston bumper 152 is a unitarily formed molded elastomeric structure. In the particular example illustrated, the piston bumper 152 has a cylindrical body portion 390 and an annular lip 392. The cylindrical body portion 390 preferably includes a first annular bumper portion 396 and a second annular bumper portion 398 that is generally larger in diameter than the first annular bumper portion 396 and which is disposed between the first annular bumper portion 396 and the annular lip 392. The annular lip 392 extends radially outwardly of the body portion 390 and includes a front abutting face 400 that is configured to abut the inside surface 402 of the housing body 160 and sealingly engage the front base 170 of the housing body 160. The annular lip 392 also includes a rear abutting face 404 having a first annular lip portion 406 and a second annular lip portion 408 that that lies radially outwardly of and recessed forwardly relative to the first annular lip portion 406. The rear abutting face 404 and a cylindrically-shaped driver blade aperture 410 that extends through the center of the piston bumper 152 will be described in detail, below.

Cap Assembly

With reference to FIGS. 11 and 12, the cap assembly 44 includes a cap housing 420, an exhaust manifold 422 and a top bumper 424. The cap housing 420 includes an outer cap wall 430 that is generally flat at the rear of the tool 10, but folds over on its sides to form a cup-like container having a generally flat forward face 432 that is configured to engage the housing seal 156 to permit the cap housing 420 to be sealingly coupled to the rear of the housing 150.

The cap housing 420 also includes a plurality of foot tabs 434, a plurality of strengthening gussets (not specifically shown), an annular exhaust port wall 438, an exhaust button 440 and a cylindrical locating hub 442 having a threaded aperture 444 formed therethrough. The foot tabs 434 extend forwardly from the flat portion of the outer cap wall 430 beyond the front face 432 by a predetermined distance. The outside diameter of the foot tabs 434 is sized such that the foot tabs 434 fit within the housing cavity 174. The foot tabs 434 will be discussed in greater detail, below. The strengthening gussets are employed to couple both the foot tabs 434 or the outer cap wall 430 to the annular exhaust port wall 438, which extends forwardly from the flat rear portion 446 of the outer cap wall 430. The exhaust button 440 is an annular member that also extends forwardly from the flat rear portion 446 of the outer cap wall 430 but which is spaced apart from the annular exhaust port wall 438 and the locating hub 442. A plurality of primary exhaust ports 450 are formed through the exhaust button 440 and a plurality of secondary exhaust ports 452 are formed through the portion of the outer cap wall 430 between the annular exhaust port wall 438 and the exhaust button 440.

The exhaust manifold 422 is preferably unitarily formed from a molded from a plastic material and includes a center hub 460, an annular spacing wall 462 and an annular manifold wall 464. The center hub 460 is configured to fit between the exhaust button 440 and the locating hub 442 and includes a hub aperture 468 that is configured to engage the locating hub 442 in a slip fit manner. The annular spacing wall 462 is coupled to the forward-most portion of the center hub 460 and is spaced apart from the exhaust button 440. The annular manifold wall 464 is coupled to the outer perimeter of the annular spacing wall 462 and includes a plurality of circumferentially extending exhaust slots 470 that are spaced around the circumference of the annular manifold wall 464. The exhaust slots 470 are generally U-shaped and as best shown in FIG. 13, have a rear edge 472 that tapers rearwardly and inwardly toward the center hub 460.

Returning to FIGS. 11 and 12, the top bumper 424 preferably includes a dampening member 480 that is molded from an elastomeric material, such as urethane, and a structural member 482, such as a washer, that is molded into the dampening member 480. The dampening member 480 is a cup-shaped structure that is sized to fit within the center hub 460 of the exhaust manifold 422. The dampening member 480 includes an annular wall 484 that extends forwardly from the base 486 of the dampening member 480. A ridge 488 is formed into the forward end of the annular wall 484, thereby creating a groove 490 between the base 486 of the dampening member 480 and the ridge 488. A plurality of slits 492 are formed into the annular wall 484, creating a plurality of wall segments 494 that are flexibly coupled to the base 486. A threaded fastener 496 is threadably engaged to the threaded aperture 444 in the locating hub 442 to fixedly but removably couple the top bumper 424 to the cap housing 420. The structural member 482 is employed so as to permit the clamping force that is exerted by the threaded fastener 496 to be transmitted through the top bumper 424 without crushing the base 486 of the dampening member 480. A portion of the clamping force is transmitted through the base 486 of the dampening member 480 and into the center hub 460 of the exhaust manifold 422 to maintain the exhaust manifold 422 in a stationary position relative to the cap housing 420.

Engine Assembly

Engine assembly 46 is shown to include a cylinder assembly 500, a piston assembly 502, a rod or driver blade 504. The cylinder assembly 500 includes a hollow, cylindrical, and unitarily constructed sleeve 510, an inner exhaust port seal 512, an outer exhaust port seal 514, a cap flange seal 516, rear and front guide seals 518 and 520, a guide assembly 522, a compensating valve 524, a rear spring flange 526, a spring 528, a front spring flange 530 and a front spring flange seal 532. In the particular embodiment illustrated, inner exhaust port seal 512, outer exhaust port seal 514, rear and front guide seals 518 and 520 and front spring flange seal 532 are conventional, commercially available O-ring seals. The cap flange seal 516 is a molded elastomeric seal having an outside surface with a generally flat seal face 540 and first and second radially inwardly extending flanges 542 and 544, respectively, that are spaced apart from one another to form an engagement groove 546 therebetween.

With additional reference to FIG. 16, the sleeve 510 is shown to include a first sleeve body portion 550, an annular sleeve flange 552, a second sleeve body portion 554 having a maximum outer diameter that is generally the same as that of the first sleeve body portion 550 and a third sleeve body portion 556 having a maximum outer diameter that is generally larger than that of the first sleeve body portion 550. The first sleeve body portion 550 includes a first U-shaped seal groove 560, which is sized to receive the front spring flange seal 532, a plurality of circumferentially-spaced front exhausting ports 562, a spring flange groove 564, which is sized to receive the rear spring flange 526, a valve groove 566, which is discussed in greater detail, below, and a second U-shaped seal groove 568, which is sized to receive the front guide seal 520.

The valve groove 566 has a first U-shaped portion 570, a second U-shaped portion 572 and a plurality of valve apertures 574. The first U-shaped portion 570 is sized to receive the compensating valve 524, which in the particular embodiment illustrated, is a flat elastomeric band 580. The second U-shaped portion 572 is disposed within the first U-shaped portion 570, but has a diameter that is somewhat smaller than that of the first U-shaped portion 570 so as to define an annular ring that extends around the circumference of the first U-shaped portion 570. In the particular embodiment illustrated, the diameter of the second U-shaped portion 572 is about 0.010 inches to about 0.030 inches smaller in diameter than the first U-shaped portion 570. The valve apertures 574 are illustrated to be relatively small diameter holes that are located within the second U-shaped portion 572 and which are drilled through the sleeve 510. The valve apertures 574 will be discussed in greater detail, below, as will the set of front exhausting ports 562 that are located between the first U-shaped seal groove 560 and the spring flange groove 564.

The annular sleeve flange 552 extends radially outwardly from the first sleeve body portion 550 of the sleeve 510 and separates the first and second sleeve body portions 550 and 554 from one another. A third U-shaped seal groove 584, which is sized to receive the rear guide seal 518 is formed into the outer surface of the annular sleeve flange 552.

The majority of the second sleeve body portion 554 of the sleeve 510 is of approximately the same outer diameter as the first sleeve body portion 550. The rear end of the second sleeve body portion 554, however, includes a flange portion 590 that extends radially outwardly to form a seal lip 592 and a fourth U-shaped seal groove 594 prior to its connection with the third sleeve body portion 556. The seal lip 592 is configured to engage the engagement groove 546 formed into the cap flange seal 516 and abut the first and second radially inwardly extending flanges 542 and 544. The fourth U-shaped seal groove 594 is configured to receive a portion of the first radially inwardly extending flange 542.

The third sleeve body portion 556 is fixedly coupled to the end of the second sleeve body portion 554 and is larger in diameter than the outer diameter of the first sleeve body portion 550. A fifth U-shaped seal groove 600 is formed into the outer surface of the third sleeve body portion 556 and is sized to receive the outer exhaust port seal 514. A plurality of circumferentially extending rear exhaust slots 604 are disposed around the perimeter of the third sleeve body portion 556. The rear exhaust slots 604 are located between the fourth and fifth U-shaped seal grooves 594 and 600. A sixth U-shaped seal groove 608, which is configured to receive the inner exhaust port seal 512, is formed into the inner diameter of the third sleeve body portion 556.

The hollow cavity 610 that is formed through the sleeve 510 has a first cavity portion 612 that is generally of a constant diameter over the portion of its length that includes the first and second sleeve body portions 550 and 554 and the annular sleeve flange 552. The hollow cavity 610 also has a second cavity portion 614 having a larger diameter than that of the first cavity portion 612.

In FIG. 14, the guide assembly 522 is shown to include a guide 650 and first and second housing seals 652 and 654, which in the particular embodiment illustrated, are O-ring seals. The guide 650 is a molded plastic component, having a stepped-diameter body portion 660, a plurality of longitudinally extending legs 662, a locating tab 664 and a plurality of stop tabs 668. The stepped-diameter body portion 660 includes a flange bore 670, which is sized to receive the annular sleeve flange 552 and sealingly engage the rear guide seal 518, a body bore 672, which is sized to receive the first sleeve body portion 550 and sealingly engage the front guide seal 520, and an abutting flange 676 that forms the transition between the flange bore 670 and the body bore 672.

The longitudinally extending legs 662 extend away from the stepped-diameter body portion 660 and are spaced apart circumferentially in equal amounts. The locating tab 664 is positioned on the same side of the stepped-diameter body portion 660 as the longitudinally extending legs 662 between two of the longitudinally extending legs 662. The locating tab 664 is employed to signify the presence of an air gallery 680 and locate the guide assembly 522 relative to the housing assembly 42. The air gallery 680 is configured to permit air to flow through the stepped-diameter body portion 660 from a point between the first and second housing seals 652 and 654 through the stepped-diameter body portion 660 and out the abutting flange 676.

The rear and front guide seals 518 and 520 and the elastomeric band 580 that forms a portion of the compensating valve 524 are initially installed to the sleeve 510. Thereafter, the guide assembly 522 is positioned over the first sleeve body portion 550 and pushed onto the sleeve 510 such that the flange bore 670 and body bore 672 are sealingly engaged to the rear and front guide seals 518 and 520, respectively, and the abutting flange 676 abuts the annular sleeve flange 552.

The rear spring flange 526 is next installed to the sleeve 510. The rear spring flange 526 is a plastic collar that is split on one side to permit the ends of the rear spring flange 526 to be spread apart so that it may be loaded onto the first sleeve body portion 550 of the sleeve 510 and into the spring flange groove 564. The rear spring flange 526 has a cylindrically shaped body portion 690 and a flange portion 692 that extends radially-outwardly from the body portion 590 in a manner that provides the rear spring flange 526 with a L-shaped cross-section. The rear spring flange 526 is located to the spring flange groove 564 such that the flange portion 692 is nearest the annular sleeve flange 552.

The front spring flange 530 is a plastic collar having a tapering outside diameter 596 and a generally flat rear face 698. The inside surface 700 of the front spring flange 530 is generally cylindrical, but includes an annular protrusion 702 that extends radially inwardly of the remainder of the inside surface 700 and which engages the first sleeve body portion 550 of the sleeve 510 in a slip-fit manner.

The spring 528 is a conventional compression spring having both ends ground flat. The spring 528 is disposed over the first sleeve body portion 550 of the sleeve 510 such that its rear end abuts the flange portion 692 of the rear spring flange 526. Thereafter, the front spring flange 530 is positioned such that its rear face 698 contacts the second end of the spring 528. The front spring flange 530 is pushed toward the annular sleeve flange 552 to compress the spring 528 a sufficient distance to permit the front spring flange seal 532 to be inserted into the first U-shaped seal groove 560. Thereafter, the front spring flange 530 is moved toward the front of the sleeve 510 such that the front spring flange seal 532 is sealingly engaged with the inside surface 700 of the front spring flange 530. The rear side of the front spring flange seal 532 contacts the annular protrusion 702 to limit the forward travel of the front spring flange 530 prior to the installation of the engine assembly 46 to the housing assembly 42. Forward motion of the guide assembly 522 along the sleeve 510 is checked by contact between the stop tabs 668 and the rear surface of the flange portion 692 of the rear spring flange 526 to thereby prevent the guide 650 from becoming disengaged from the rear and front guide seals 518 and 520. Construction in this manner is highly advantageous in that it permits the entire cylinder assembly 500 to be pre-assembled outside of the housing assembly 42 in a relatively easy and cost efficient manner.

The piston assembly 502 includes a piston 720 and a ring 722. In the example provided, the piston 720 is shown to include a first piston portion 730 and a second piston portion 732. The first piston portion 730 in an annular member that is smaller in diameter than the first cavity portion 612 of the hollow cavity 610 in the sleeve 510. A U-shaped annular ring groove 734 is formed around the circumference of the first piston portion 730 that is sized to receive the ring 722. In the embodiment illustrated, the ring 722 is shown to be fabricated from a plastic material and have a rectangular cross-section. The ring 722 is split to permit its ends of the ring 722 to be spread apart so that it may be loaded around the first piston portion 730 and into the ring groove 734. The second piston portion 732 is an annular member that is smaller in diameter than the first piston portion 730. The second piston portion 732 is coupled to the rear end of the first piston portion 730 and includes a pair of wrench flats 740 and a locking protrusion 744, both of which will be discussed in more detail, below. A generous fillet radius 746 is employed at the intersection between the first and second piston portions 730 and 732 so as to reduce the concentration of stress within the piston 720.

The construction of the driver blade 504 is largely conventional and as such, a detailed discussion of it is neither required nor within the scope of this disclosure. Briefly, the driver blade 504 is shown to include a coupling portion 760 and a driver body 762. In the example provided, the coupling portion 760 includes a collar 764 and a threaded portion 766 which are formed into the rear end of the driver blade 504. The wrench flats 740 on the second piston portion 732 are employed to facilitate relative rotation between the driver blade 504 and the piston 720 to permit the threaded portion 766 to threadably engage a threaded aperture 768 that is formed through the piston 720 and to permit the collar 764 to engage the front surface 770 of the piston 720 to generate a clamping force that fixedly but removably couples the piston 720 and the driver blade 504 together. Coupling of the piston 720 and the driver blade 504 via a threaded connection is presently preferred so as to permit the servicing and replacement of the driver blade 504, since this portion of the tool 10 is essentially perishable. Those skilled in the art will understand, however, that other coupling mechanisms, such as press-fitting, shrink fitting, welding, or any other mechanical coupling method may also be employed.

The driver body 762 is sized to fit in the blade cavity 82 and is shown to include a keyway 774, a slide surface 776, a loading groove 778 and a tip portion 780. The keyway 774 is illustrated to be a cut that is formed into the surface of the driver body 762 along its longitudinal axis. The fastener stop 102 that is formed into the internal cavity 100 in the nose guide 98 is disposed within the keyway 782 to guard against a situation wherein fasteners F feed rearwardly into the tool 10. The slide surface 776 is generally flat and provides the driver body 762 with a relatively large surface that will consistently slide over the fasteners F that are loaded into the magazine assembly 20. The tip portion 780 is formed at the front end of the driver body 762 and is operable for contacting the fasteners F and driving them into a workpiece. The loading groove 778 is cylindrically shaped and is formed along an axis that is skewed to the longitudinal axis of the driver blade 504 such that it intersects both the tip portion 780 and the slide surface 776. The loading groove 778 is tapered such that it is deepest at the front of the driver blade 504. The loading groove 778 ensures that only one fastener F is sheared from the remaining fasteners F in the magazine assembly 20. The loading groove 778 also permits the fasteners F in the magazine assembly 20 to move upwardly toward the nose body 60 of the tool 10 prior to the time at which the driver blade 504 has stroked back to its rear-most (i.e., retracted) position to thereby minimize the lag time between the point at which the driver blade 504 has moved to its retracted position and the point at which the driver blade 504 can be moved forwardly to drive another fastener F.

With additional reference to FIGS. 16 and 17, the driver blade 504 and the piston assembly 502, once coupled to one another, are inserted into the second cavity portion 614 of the hollow cavity 610 in the sleeve 510. The diameter of the second cavity portion 614 is larger than the diameter of the piston assembly 502 (with the ring 722 in an expanded condition). A chamfer 790 is employed at the front of the second cavity portion 614 to facilitate the transition to the smaller-diameter first cavity portion 612. With the exertion of light force onto the rear of the piston assembly 502, the piston assembly 502 is moved forwardly in the hollow cavity 610 and into contact with the chamfer 790. The chamfer 790 is operable for compressing the ring 722 to permit the piston assembly 502 to travel into the first cavity portion 612.

Once assembled, the engine assembly 46 is placed into the housing cavity 174 such that the locating tab 664 is aligned to a tab slot 800 formed into the housing cavity 174 and the driver blade 504 is inserted through the driver blade aperture 410 in the piston bumper 152 and into the internal cavity 100 in the nose guide 98. The engine assembly 46 is pushed forwardly into the housing cavity 174 to engage the guide assembly 522 against the guide stop 184. In this position, the first and second housing seals 652 and 654 sealingly engage the guide bore 180 that is formed into the inside surface 182 of the outwardly tapering sidewall 172. The first and second annular bumper portions 396 and 398 extend through the front face 810 of the sleeve 510 and into the hollow cavity 610. The front face 820 of the front spring flange 530 sealingly contacts the second annular lip portion 408 on the piston bumper 152. The cap assembly 44 is thereafter placed onto the rear end of the housing assembly 42 such that each of the longitudinally extending legs 662 contacts one of the foot tabs 434. The foot tabs 434 cooperate with the longitudinally extending legs 662 to prevent the guide assembly 522 from moving along the longitudinal axis of the tool 10. The sleeve 510, however, is slidable within the guide assembly 522, as will be discussed in greater detail, below.

Alternatively, the piston assembly 502 and driver blade 504 may be inserted into the housing cavity 174 such that the driver blade 504 is inserted through the driver blade aperture 410 in the piston bumper 152 and into the internal cavity 100 in the nose guide 98. The cylinder assembly 500 is then loaded into the housing cavity 174 in the manner discussed above. A lead L formed into the front face 810 of the sleeve 510 that permits the ring 722 to be compressed so that the piston assembly 502 can travel rearwardly into the first cavity portion 612 of the hollow cavity 610 in the sleeve 510.

Engine Operation

With reference to FIGS. 10, 14 and 16, when the tool 10 has been coupled to a source of compressed air, the trigger assembly 48 maintains the trigger valve 130 in an unactuated state wherein compressed air is directed from the supply port 370 to the biasing port 372 where it enters the air gallery 680 at a point between the first and second housing seals 652 and 654. Compressed air flows thr