RIVET GUN
A rivet gun for setting a self-tapping rivet in one or more work pieces has a tool body having a handle for gripping, a rotation assembly having a motor attached to an axially adjustable shaft and a chuck to thereby impart rotation to the chuck adapted to grip and rotate the shank of the self-tapping rivet. A hydraulic assembly having a pull bushing is connected to a piston rod attached to a piston and a retraction assembly having a mandrel clamp and a mandrel clamp ring is connected to a spring guide biased toward the mandrel clamp by a spring to thereby compress the mandrel clamp to grip and retract the shank, set the self-tapping rivet in the work pieces and detach the shank from the self-tapping rivet.
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The present invention generally relates to a field of tools and devices for setting rivets, and more particularly to a rivet gun suitable for setting self-tapping rivets.
BACKGROUND OF THE INVENTIONBlind setting rivets are usually set in a work piece using a rivet setting tool or device which may be pneumatically, electrically, or hydraulically powered. Blind setting rivets typically include a hollow rivet body and a mandrel disposed longitudinally within the hollow rivet body. The mandrel includes a shank terminating in the head for radially compressing and spreading the rivet body as the mandrel is retracted rearward relative to the rivet body. The shank includes an area of reduced diameter for allowing the head to detach from the shank upon application of predetermined tinsel force supplied to the shank. To set a blind setting rivet, the shank of the rivet mandrel is inserted into the rivet gun. The tubular portion of the hollow rivet body is inserted through a hole formed in the work piece and the rivet gun is activated, retracting the shank rearward relative to the rivet body, causing the head to compress and spread the rivet body to set the rivet. The shank then separates from the head at the area of reduced diameter and is discarded. Some examples of self-tapping, blind setting rivets, are described in U.S. Pat. Nos. 5,741,099, 5,762,456, 5,915,901, 6,904,831, and 6,796,759. In this manner, a separate pole-drilling step may be eliminated when applying the rivet. However, because conventional rivet setting tools do not rotate the mandrel rivet, application of such self-tapping rivets currently require the use of a drill for rotating the rivet mandrel to tap a hole in the work piece. The rivet setting device may then be used setting the rivet in the work piece and detaching the shank from the rivet. This use of two separate tools slows application of the rivets, reduces their advantage over non-tapping varieties.
Consequently, it would be advantageous to provide a rivet gun suitable for setting self-tapping rivets. The rivet gun should be capable of gripping and turning the mandrel of the rivet in order to turn the self-tapping head of the rivet for tapping a hole in one or more work pieces.
BRIEF SUMMARY OF THE INVENTIONThe present invention is directed to a rivet gun for setting a self-tapping rivet. In one embodiment of the present invention, a rivet gun for setting a self-tapping rivet having a mandrel with a shank and a self-tapping head, a weakened area of reduced diameter and a hollow rivet body surrounding the mandrel for joining one or more work pieces is disclosed. The rivet gun includes a tool body having a handle for gripping, a rotation assembly having a motor attached to an axially adjustable shaft, mandrel clamp and a chuck to thereby impart rotation to the chuck adapted to grip and rotate the shank of the self-tapping rivet, and a hydraulic assembly connected to a retraction assembly adapted to first grip and retract the shank to set the self-tapping rivet in the work pieces by compressing and spreading the hollow body with the head and second detach the shank from the head at the weakened area of reduced diameter. In a preferred embodiment, the rivet gun also has a braking assembly having a brake disk extending radially outward from a drive shaft connected to the rotation assembly and a brake body with a brake pad biased toward a non-braking position by a brake spring and actuatably urged by a piston against the brake disk to thereby brake rotation of the rotation assembly. A pair of triggers on the handle are mechanically or pneumatically interlocked for operating the rivet gun and to prevent simultaneous operation of both triggers. The axially adjustable shaft has a drive shaft and a drive shaft coupling having axially extending fingers adapted to mate within and slide relative to similarly shaped groves in the drive shaft. The retraction assembly also has a mandrel clamp ring circumferentially positioned around the mandrel clamp and connected to a spring guide biased toward the mandrel clamp by a spring to thereby compress the mandrel clamp to grip the shank. The hydraulic assembly has a piston connected to a piston rod attached to a pull bushing and being hydraulically actuated to retract the pull bushing rearward by communicating hydraulic fluid into a chamber between the piston and seal body to retract the mandrel clamp rearward. The rivet gun also has a mandrel collector attached rearward of the tool body and in communication with a mandrel tube extending through the rotation assembly for collecting detached shanks.
A new method for setting a self-tapping rivet in one or more work pieces is disclosed. The method includes taking a rivet gun having a motor for rotating a chuck, inserting a shank of the self-tapping rivet into the chuck for gripping the shank, rotating the chuck with an axially adjustable shaft attached to the motor for creating a hole through the work pieces with a self-tapping head of the self-tapping rivet, moving a brake body with brake pads into contact with a brake disk attached to the axially adjustable shaft for braking rotation of the axially adjustable shaft, retracting a piston rearward with a piston rod attached to a pull bushing, and compressing a mandrel clamp with a mandrel clamp ring to grip the shank for setting the self-tapping rivet in the work pieces and detaching the shank from the self-tapping head. In the preferred form, the method also includes the step of urging the mandrel clamp ring forward against the mandrel clamp with a spring guide biased toward the mandrel clamp by a spring, communicating pressurized hydraulic fluid into a chamber between a seal body and the piston for driving the piston rearward away from the seal body and imparting rearward movement to the pull bushing for retracting the mandrel clamp, and sliding axially extending fingers of a drive shaft coupling within and relative to similarly shaped groves in the drive shaft when retracting the mandrel clamp.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not necessarily restrictive of the invention as claimed. The accompanied drawings, which are incorporated in and constitute a part of the specification, illustrate one or more embodiments of the present invention and together with the general description, serve to explain the principles of the invention.
The numerous advantages of the present invention may be better understood by those skilled in the art by reference to the accompanying figures in which:
Reference will now be made in detail to the presently preferred embodiments of the invention, examples of which are illustrated in the accompanied drawings.
Referring generally to
The rivet gun 100 has a tool body 101 where the various parts and components of the rivet gun 100 are positioned therein or attached thereto. The tool body 101 may be a unitary-constructed, molded piece or formed by several separate enclosures. The rivet gun 100, as is generally appreciated and known for operation, has a handle 103 for gripping and a pair of triggers 244, 245. The rivet gun 100 may also have a pressure intensifier 250 in communication with an air input 264 as is customary and known in the art.
In the preferred embodiment, the tool body 101 of the rivet gun 100 has a front cap 182 threadably attached to enclosure 174 (generally enclosing the chuck bearings). Enclosure 174 is threadably attached to enclosure 177 (generally enclosing the spring 162 and power pull bushing 140) which is in-turn coupled to enclosure 176 (generally enclosing the hydraulic assembly 119) and enclosure 178 (generally enclosing a flange of the motor) by a bolt. The front cap 182 and enclosures 174, 177, 176, and 178 are attached to enclosure 184 (generally enclosing the motor 180) by threadably connecting enclosure 178 to enclosure 184. The mandrel collector 212 is threadably attached to enclosure 184 to form a substantial portion of the tool body 101. Although the preferred assembly has been described, it should be understood that each of the enclosures may be connected together by way of threads, locking detents, snap fittings, or otherwise. Similarly, the tool body 101 could be formed as a unitary piece, shell or molding.
The rivet gun 100 is designed to perform generally the functions of gripping and rotating the shank 110 of the self-tapping rivet 102 and retracting the shank 110 of the self-tapping rivet 102 to set the self-tapping rivet 102 within a work piece 112. The various parts, components and assemblies to effectuate these functions are discussed in the proceeding paragraphs and characterized in part by a rotation assembly 115, a retraction assembly 117 and a hydraulic assembly 119.
Rotation AssemblyThe rotation assembly 115 is driven by a motor 180. The motor 180 is preferably an air-driven motor; however, it should be appreciated by those skilled in the art that the motor 180 could also be electrically or hydraulically driven. The motor 180 is secured within enclosure 184 by back plate 190 and motor flange enclosure 178. In the preferred embodiment, the back plate 190 is threadably attached to enclosure 184, but may be attached by alternative means, such as screws, snap fits, detents, or otherwise. A pusher 194 is positioned within the motor clamp 192 and secured to the back plate 190. In addition to supporting the pusher 194 and motor clamp 192, the back plate 190 supports mandrel tube 214 extending through the center of back plate 190 by whereby detached shanks 110 from the self-tapping rivet 102 are shuttled therethrough into mandrel collector 212. Also supported by back plate 190 is mandrel tube clamp 188, which supports and locks the mandrel tube 214 in place. The mandrel tube 214 extends through the back plate 190 (as previously described), motor 180, brake body 172, brake disk/motor drive shaft 170, outer drive shaft 166, draft shaft coupling 168, drive shaft 164, and mandrel clamp 154.
Connected to the output shaft of the motor 180 is brake disk/motor drive shaft 170. The output shaft of the motor 180 may be rotatably connected to impart rotation to the brake disk/motor drive shaft 170 by way of a key and keyway (not shown), as is customary for transferring rotation from one shaft to another connected shaft. A brake body 172 with brake pads 222 is attached to the back plate 190 between the brake disk/motor drive shaft 170 and the back plate 190. The brake body 172 is permitted to move axially provided by brake pad piston 228 being pneumatically actuated. The forward axial movement of the brake body 172 is resisted by brake spring 272, which forces the brake body 172 rearward relative to the brake disk/motor drive shaft 170 when brake pad piston 228 is inactive. Thus, the forward axial movement of the brake body 172 moves brake pads 222 into braking contact with the brake disk/motor drive shaft 170 for braking rotation of the brake disk/motor drive shafts 170. Operation of the braking assembly 121, shown generally in
Continuing discussion of the rotation assembly 115, the outer drive shaft 166 is connected to adapt to house drive shaft coupling 168. The drive shaft coupling 168 has fingers extending from the base which are received within the grooves in the drive shaft 164 to impart rotational movement from the outer drive shaft 166 to the drive shaft 164 yet still permit the drive shaft 164 to translate axially within the drive shaft coupling 168 within the outer drive shaft 166 (See
Mounted on the outer circumference of the mandrel clamp 154 is a needle roller runner 201. Also, to rotatably support the mandrel clamp 154 within the mandrel clamp ring 156, drive shaft bearings 158 are positioned along the outer circumference of the mandrel clamp 154. The drive shaft bearings 158 along with needle roller runner 201 support the rotation of the mandrel clamp 154.
Threadably attached to the outer circumference of the mandrel clamp ring 156 is spring chamber guide 160. Spring chamber guide 160 houses spring 162 between a radially extending flange on the piston rod 132 and the spring chamber guide 160. Spring 162 biases the spring chamber guide 160 away from the piston rod 132 which in turn biases the mandrel clamp ring 156 against the mandrel clamp 154. The mating surfaces between the mandrel clamp ring 156 and the mandrel clamp 154 may be angled to impart compression forces to thereby reduce the cross-sectional area of the mandrel clamp 154 (See
Also attached along the outer circumference of the mandrel clamp ring 156 is a threaded front bearing adjustment 129B. The threaded front bearing adjustment 129B has threads along its outer circumference for securing enclosure 174 thereto. Positioned within the threaded front bearing adjustment 129B is chuck needle thrust bearing 128. Secured also within the threaded front bearing adjustment 129B adjacent the chuck needle thrust bearing 128 is a front needle bearing runner 129A. Spaced between the enclosure 174 and front bearing runner 122 is chuck needle roller bearing 126 supported on its opposite ends by front needle bearing runner 129A and a radially extending flange on front bearing runner 122. A front needle bearing runner 203 is also positioned between the enclosure 174 and chuck needle roller bearing 126 for rotatably supporting the mandrel clamp 154. Positioned within chuck 118 between chuck cap 120 and a radially extending flange on the chuck 118 and resting adjacent the mandrel clamp 154 are several chuck clamp bodies 200. The chuck clamp bodies 200 are rotatably supported within the chuck 118 by chuck thrust ball bearing cage 124. The mandrel clamp 154 has rips 270 for gripping the shank 110 of the self-tapping rivet 102. A mandrel clamp disk 198 is also positioned behind the front cap 182 between the chuck 118 to help encourage retention of the mandrel 106 shank 110 within the chuck 118 before the chuck clamp bodies 200 within the chuck 118 engage the shank 110 of the self-tapping rivet 102.
The various components and parts of the rotation assembly 115 have been generally described. Conceptually, rotation of the motor drive shaft 170 imparts rotation to the mandrel clamp 154 which in turn causes chuck clamp bodies 200 within chuck 118 to engage the shank 110 of the self-tapping rivet 102. This is accomplished as rotation is imparted from the motor 180 to the brake disk/motor drive shaft 170 which is threadably attached to the outer drive shaft 166. The motor drive shaft 166 in-turn imparts rotational movement to drive shaft coupling 168 which in-turn rotates drive shaft 164. Mandrel clamp 154 is threadably received within drive shaft 164 so that rotation of drive shaft 164 causes the mandrel clamp 154 to rotate as well. Lastly, rotation of the mandrel clamp 154 imparts rotation to the chuck clamp bodies 200 contained within the chuck 118 whereby the chuck clamp bodies 200 move from a larger diameter to a smaller diameter to thereby clamp and rotate the shank 110 of the self-tapping rivet 102.
Retraction & Hydraulic AssembliesIn addition to the rotation assembly 115, the rivet gun 100 has a retraction assembly 117 for retracting the mandrel 106 rearward relative to the hollow rivet body 104 for compressing and spreading the hollow rivet body 104 using the self-tapping head 108 of the self-tapping rivet 102. In the preferred embodiment, the retraction assembly 117 works in concert with a hydraulic assembly 119 (See
The hydraulic assembly 119 is sealably contained within enclosure 176 by piston lip seal 216, piston rod lip seal 218 and piston lip seal backup ring 220. An aperture is configured into the enclosure 176 for passing high pressure hydraulic fluid through the enclosure 176 into the hydraulic assembly 119 within a hydraulic oil chamber 268 between piston 130 and piston rod seal body 134. A pressure intensifier 250, as are well known in the art, may be used to convert compressed air from compressed air supply line 262 (See
The release of hydraulic fluid from the hydraulic oil chamber 268 allows spring 162 to move the spring chamber guide 160 forward in an axial direction. Releasing hydraulic fluid from the hydraulic oil chamber 268 also causes piston 130 to move from a position adjacent damper plate 224 to a position adjacent piston rod seal body 134 (See
The braking assembly 121 is shown generally in
It is believed that the present invention and many of its attendant advantages will be understood by the foregoing description, and it will be apparent that various changes may be made in the form, construction and arrangement of the components thereof without departing from the scope and spirit of the present invention or without sacrificing all of its material advantages.
Claims
1. A rivet gun for setting a self-tapping rivet having a mandrel with a shank and a self-tapping head, a weakened area of reduced diameter and a hollow rivet body surrounding the mandrel for joining one or more work pieces, the rivet gun comprises:
- a tool body having a handle for gripping;
- a rotation assembly having a motor attached to an axially adjustable shaft connected to a chuck to impart rotation to the chuck adapted to grip and rotate the shank of the self-tapping rivet;
- a hydraulic assembly;
- a retraction assembly adapted to grip the shank of the self-tapping rivet; and
- the hydraulic assembly connected to the retraction assembly adapted to retract the shank to set the self-tapping rivet in the work pieces and detach the shank from the self-tapping head at the weakened area of reduced diameter.
2. The rivet gun of claim 1 further comprises a braking assembly having a brake disk extending radially outward from a drive shaft connected to the rotation assembly.
3. The rivet gun of claim 2 wherein the braking assembly further comprises a brake body with a brake pad biased toward a non-braking position by a brake spring and actuatably urged by a piston against the brake disk to thereby brake rotation of the rotation assembly.
4. The rivet gun of claim 1 further comprises a pair of triggers on the handle mechanically or pneumatically interlocked for operating the rivet gun and to prevent simultaneous operation of both triggers.
5. The rivet gun of claim 1 wherein the axially adjustable shaft further comprises a drive shaft and a drive shaft coupling having axially extending fingers adapted to mate within and slide relative to similarly shaped groves in the drive shaft.
6. The rivet gun of claim 1 wherein the retraction assembly further comprises a mandrel clamp and a mandrel clamp ring circumferentially positioned around the mandrel clamp and connected to a spring guide biased toward the mandrel clamp by a spring to thereby compress the mandrel clamp to grip the shank.
7. The rivet gun of claim 1 wherein the hydraulic assembly further comprises a piston connected to a piston rod attached to a pull bushing and being hydraulically actuated to retract the pull bushing rearward by communicating pressurized hydraulic fluid into a chamber between the piston and a seal body.
8. The rivet gun of claim 7 wherein the pull bushing is adapted to retract the mandrel clamp rearward.
9. The rivet gun of claim 1 further comprising a mandrel collector attached rearward of the tool body and in communication with a mandrel tube extending through the rotation assembly for collecting detached shanks.
10. A rivet gun for setting a self-tapping rivet in one or more work pieces, the rivet gun comprises:
- a tool body having a handle for gripping;
- a rotation assembly having a motor attached to an axially adjustable shaft and a chuck to thereby impart rotation to the chuck adapted to grip and rotate the shank of the self-tapping rivet;
- a hydraulic assembly having a pull bushing connected to a piston rod attached to a piston, and
- a retraction assembly having a mandrel clamp and a mandrel clamp ring connected to a spring guide biased toward the mandrel clamp by a spring to thereby compress the mandrel clamp to grip and retract the shank, set the self-tapping rivet in the work pieces and detach the shank from the self-tapping rivet.
11. The rivet gun of claim 10 wherein the axially adjustable shaft further comprises a drive shaft and a drive shaft coupling having axially extending fingers adapted to mate within and slide relative to similarly shaped groves in the drive shaft.
12. The rivet gun of claim 11 wherein the mandrel clamp is connected to the drive shaft.
13. The rivet gun of claim 12 wherein pressurized hydraulic fluid communicated into a chamber between the piston and a seal body causes rearward movement of the piston, the piston rod and the pull bushing which imparts rearward movement to the mandrel clamp.
14. The rivet gun of claim 10 wherein the motor is pneumatically or electrically driven.
15. The rivet gun of claim 10 wherein the chuck further comprises a plurality of clamp bodies adapted to move from a large cross-section to a smaller cross-section for gripping the shank upon rotation of the chuck and/or rotation assembly.
16. The rivet gun of claim 10 wherein the handle has an air input for communicating compressed air into the rivet gun.
17. A method for setting a self-tapping rivet in one or more work pieces, the method comprising:
- taking a rivet gun having a motor for rotating a chuck;
- inserting a shank of the self-tapping rivet into the chuck for gripping the shank;
- rotating the chuck with an axially adjustable shaft attached to the motor for creating a hole through the work pieces with a self-tapping head of the self-tapping rivet;
- moving a brake body with brake pads into contact with a brake disk attached to the axially adjustable shaft for braking rotation of the axially adjustable shaft;
- retracting a piston rearward with a piston rod attached to a pull bushing; and
- compressing a mandrel clamp with a mandrel clamp ring to grip the shank for setting the self-tapping rivet in the work pieces and detaching the shank from the self-tapping head.
18. The method of claim 17 further comprising the step of urging the mandrel clamp ring forward against the mandrel clamp with a spring guide biased toward the mandrel clamp by a spring.
19. The method of claim 17 further comprising the step of communicating pressurized hydraulic fluid into a chamber between a seal body and the piston for driving the piston rearward away from the seal body and imparting rearward movement to the pull bushing for retracting the mandrel clamp.
20. The method of claim 17 further comprising the step of sliding axially extending fingers of a drive shaft coupling within and relative to similarly shaped groves in the drive shaft when retracting the mandrel clamp.
21. A method for setting a self-tapping rivet in one or more work pieces, the method comprising:
- taking a rivet gun having a rotation assembly with a motor for imparting rotation to a chuck, a braking assembly for braking rotation of the rotation assembly and a hydraulic assembly for imparting rearward movement to a retraction assembly;
- inserting a shank of the self-tapping rivet into the chuck;
- running the motor to rotate the chuck and tap a hole in the work pieces with the self-tapping rivet;
- activating the braking assembly by moving a brake body with brake pads into contact with a brake disk of the braking assembly;
- engaging the hydraulic assembly to move a piston with a piston rod attached to a pull bushing rearward for imparting rearward movement to the mandrel clamp; and
- retracting the mandrel clamp for setting the self-tapping rivet in the work pieces and detaching the shank.
22. The method of claim 21 further comprising the step of pressing a first trigger for disengaging the brake assembly and activating the rotation assembly.
23. The method of claim 22 further comprising the step of pressing a second trigger for engaging the brake assembly and activating the hydraulic assembly and the retraction assembly.
24. The method of claim 23 further comprising the step of mechanically or pneumatically interlocking the first trigger and the second trigger to prevent simultaneous operation of both triggers.
25. The method of claim 21 further comprising the step of rotating the chuck one direction for gripping and rotating the shank with a plurality of clamp bodies and an opposite direction for releasing the plurality of clamp bodies from the shank.
26. The method of claim 21 further comprising the step of connecting an axially adjustable shaft to the mandrel clamp for retracting the mandrel clamp.
27. The method of claim 21 further comprising the step of ejecting detached shanks from the self-tapping rivet from the mandrel clamp through a mandrel tube into a mandrel collector behind the motor.
Type: Application
Filed: Aug 1, 2007
Publication Date: Feb 5, 2009
Applicant: ABEO, LLC (Omaha, NE)
Inventor: WOLF-DIETER KEPPEL (Chicago, IL)
Application Number: 11/832,226
International Classification: B21J 15/20 (20060101);