US3713321A

US3713321A - Rivet gun

Info

Publication number: US3713321A
Application number: US00165009A
Authority: US
Inventors: Pointe G La
Original assignee: Parker Manufacturing Co
Current assignee: Parker Manufacturing Co
Priority date: 1971-07-22
Filing date: 1971-07-22
Publication date: 1973-01-30
Anticipated expiration: 1990-01-30

Abstract

A rivet gun for use with blind rivets making use of a closedcircuit hydraulic system.

Description

United States Patent [191 LaPointe [54] RIVET GUN [75] Inventor: Gabriel M. Lalointe, Worcester,

Mass.

[73] Assignee: Parker Manufacturing Company;

Worcester, Mass,

[22] Filed: July 22, 1971 [2i] Appl. No.: 165,009

52 u.s.c| ....:.....72/s91,72/453 [S 1] int. Cl. ..B21j 15/20 [58] Field of Search .;.....72/39l, 453, 114

[56] References Cited UNITED STATES PATENTS 2,365,538 12/1944 Fischer ..72/453 Jan. 30, 1973 2,526,956 l0/l950 Kugler ..72/39r 3,082,898 3/1963 Bosch ..72/39l 3,254,522 6ll966 Elliott ....72 391 FOREIGN PATENTS 0R APPLICATIONS 550,230 l2/l942 Great Britain ..72/391 Primary Examiner-Richard J. l-lerbst Assistant Examiner-Gene P. Crosby Attorney-Norman S. Blodgett [57] ABSTRACT A rivet gun for use with blind rivets making use of a closed-circuit hydraulic system.

13 Claims, 12 Drawing Figures PATENTEDJAII 30 ms sum 1 or 4 GABRIELM. LAPo/NrE INVENTOR RIVET GUN BACKGROUND OF THE INVENTION In the art of riveting, it has become common practice to make use of the so-called blind rivet". This is a rivet which is tubular in nature and consists of a short tube having a radial flange at one end. A headed mandrel (similar to a common nail) extends through the tube with its head at the end of the tube opposite the flanged end. It is possible to join two sheet metal articles by passing the tubular portion of the rivet through matching holes in the metal objects and, while holding the flange tightly against one side of the assemblage, pulling the mandrel. The head of the mandrel or nailcauses a flange to be formed on the free end of the tube and this flange is pressed tightly against the other side of the assemblage to form a rivet. The strength of the mandrel is such that tremendous forces are developed in forming the rivets and, eventually, the mandrel breaks. The headed end of the mandrel remains in the rivet or may fall out, but takes no part in the function of the rivet as a fastener.

In the past, many rivet guns have been developed and, generally speaking, they are either commercial or home handyman-type rivet guns. The handyman" rivet gun is usually a mechanical one which makes use of levers and ratchets to develop the forces in the mandrel. Such guns have been limited in the past to small rivets, since the forces that must ,be developed in the mandrel in large rivets are very large and cannot be developed by simple inexpensive mechanical means. A commercial rivet gun has usually been connected to a source of pressure air. Examples of these commercial guns are shown in the U.S. Pat. to Bosch No. 3,082,898, to Fischer U.S. Pat. No. 2,365,538, and EI- liott et al. U.S. Pat. No. 3,254,522. In all of these prior art constructions, the primary force comes about by the use of a pneumatic motor. The pneumatic motor, in turn, operates a hydraulic piston which, in turn, produces the force which brings about the pulling of the mandrel. Since the average home workman does not have pressure air available, he is not able to make use of these hydraulically operated rivet guns and, therefore, cannot use large blind rivets. At the same time, even in commercial applications where it is desirable to do a riveting operation in inaccessible areas, the use of the rivet gun is limited by the unavailability of pressure area in such areas. Furthermore, all of these hydraulically operated rivet guns are very expensive because they involve rather complex machined elements. These and other difficulties experienced with the prior art devices have been obviated in a novel manner by the present invention.

It is, therefore, an outstanding object of. the invention to I provide a rivet gun using hydraulic operation without the necessity of a connection to an external power source.

Another object of this invention is the provision of a rivet gun of compact size capable of producing large forces for use with large blind rivets.

A further object of the present invention is the provision of a blind rivet gun capable of producing large forces by use of a hydraulic system.

I It is another object of the instant invention to provide a hydraulic blind rivet gun whose main body element is capable of production by the injection molding of aluminum or similar metal.

A still further object of the invention is the provision of a rivet gun producing a force on the mandrel, which force is entirely controllable by the operator.

his a further object of the invention to provide a rivet gun which is in the shape of a conventional pistol having an elongated barrel extending at a right angle to a hand grip and having the mandrel-pulling apparatus at the end of the barrel, thus allowing the rivets to be placed in difficuItto-reach places and arranged so that the operator can work for a long period of time without becoming tired.

With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.

SUMMARY OF THE INVENTION In general, the invention consists of a rivet gun for usewith a hollow rivet having a mandrel and having a main body having a hand grip and a barrel. A squeeze lever is hingedly attached to the main body adjacent the hand grip and a mandrel grip and a rivet handle is mounted on the free end of the barrel. A primary piston system is carried in the handle and is operable by the trigger. A secondary piston system is carried in the barrel and connected to the rivet anvil. A reservoir is provided for containing a body of hydraulic fluid and a check valve is located between the primary piston system and the secondary piston system.

BRIEF DESCRIPTION OF THE DRAWINGS The character of the invention, however, may be best understood by reference to one of its structural forms, as illustrated by the accompanying drawings, in which:

FIG. 1 is a perspective view of a rivet gun embodying the'principles of the present invention,

FIG. 2 is a side elevational view of the rivet gun,

FIG. 3 is an end elevational view of the gun,

FIG. 4 is an opposite end elevational view of the gun,

FIG. 5 is a plan view of the gun,

FIG. 6 is an opposite side elevational view of the gun,

FIG. 7 is a bottom view of the gun,

FIG. 8 is a sectional view of the gun taken on the line vm-vm of FIG. 3,

FIG. 9 is a sectional view of a portion of the invention taken on the line IX-IX of FIG. 8,

FIG. 10 is a view taken along the line X-X of FIG. 1

FIG. 11 is a sectional view of the invention taken on the line XIXI of FIG. 8, and

FIG. 12 is a sectional view of the invention taken on the line XII-XII of FIG. 8.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIGS. 1, 2, 3, 4, 5, 6, and 7, which best show the general features of the invention, the rivet gun, indicated generally by the reference numeral 10, is shown as having a main body 11 having a hand grip 12 and a barrel 13. The squeeze lever 14 is pivotally attached to the main body 11 adjacent the hand grip 12. The mandrel grip l5 and a rivet anvil l6 are mounted on the free end of the barrel 13. The barrel actuator 17 is mounted on the side of the barrel 13. Also evident in these figures is a lever system 18 connecting the squeeze lever 14 to the interior of the handle grip 12.

FIG. 8 shows in general the interior construction of the gun. A primary piston system 19 is carried in the handle 12 and is operable by the squeeze lever 14. A secondary piston system 21 is carried in the barrel 13 and is connected to the rivet anvil 16. A reservoir 22 is provided in the barrel 13 for containing a body of hydraulic fluid. The reservoir 22 is expandable by virtue of the fact that it is provided with a bore 23 in which is slidably carried a piston 24. A coil spring 25 lies between the outer end of the bore 23 and the piston 24. The second piston system 21 includes a power bore 26 extending longitudinally of the barrel 13. The first piston system 19 includes a pump bore 27 extending at a right angle to the power bore 26. The bore 23 of the reservoir 22 is aligned with the power bore 26. The reservoir bore 23 and the power bore 26 are separated by a substantial space and an imaginary extension of the pump bore 27 would pass'through that space. As has been stated, the squeeze lever 14 is connected to the first piston assembly 19 by a lever system 18. The squeezing of the lever toward the hand grip 12 causes a point in the system to move the first piston system. The squeeze lever 14 isprovided with a protuberance 28 extending from the side of the lever facing the hand grip 12. The protuberance has a pivot pin 29 which moves parallel to the axis of the pump bore 27 when the squeeze lever 14 is moved toward the handle grip 12. One end of a first link 31 is pivotally connected to the squeeze lever 14 by the said pivot pin 29. One end of a second link 32 is pivotally connected to the handle grip 12 by a pivot pin 33. The first link 31 is formed with an integral bellcrank arm 34. The ends of the

links

31 and 32 are connected by a pivot pin 35. The bellcrank arm 34 extends beyond the pivotal connection 35 between the links and engages a pump piston 36 of the first piston system 19. A coil spring 37 which is concentric with the pump piston 36 is operative to bias the pump piston and the bellcrank arm 34 in the downward direction, i.e., the direction to move the squeeze lever '14 away from the hand grip 12.

'The secondary piston system 21 includes the power bore 26 extending longitudinally of the barrel 13 and a piston 38 with a piston rod 39 extending to the end of the barrel 13 and connected to the rivet anvil 16. The anvil has a bore 41 that is parallel to and spaced from the power bore 26. The rivet anvil 16 is provided with a hardened metal nose or insert 42 in which the bore 41 is formed. Inside the mandrel grip are provided jaws 43 adapted to grip the mandrel of the pop rivet. They are maintained in a normally open position by a plunger 44 which is biased toward the jaws by a coil spring 45. The large coil spring 46 biases the piston 38 to the right in its bore 26.

Referring now toFlGS. 9 and 10, the check valve 47 is mounted between the primary piston system 19 and the secondary piston system 21. More specifically, it is connected on one side to the upper end of the bore 27 and a passage 48 leading to the inner end of the bore 26 from the side of the piston 38 away from the'piston rod 39 and the coil spring 46. The check valve is provided with a ball 49 which is spring-biased toward a seat leading to a vestibule 51. The vestibule is not only connected in its central part to the top of the bore 27 of the first piston system 19, but also is provided at the other end with a seat 52 which is connected to a passage 53 leading to the reservoir 22. A ball 54 is pressed against the seat 52 to form a check valve by a coil spring 55 i which extends between the ball 54 and the ball 49. Generally speaking, the ball 49 pulls away from its seat to allow the pressure hydraulic fluid to flow from the bore 27 to the piston 38 when the piston 36 is moved upwardly, while the ball 54 moves to the right (in FIG. 9) to connect the passage 53 to the bore 27, to allow fluid to be sucked from the reservoir 22 into the bore 7 27 when the piston 36 moves downwardly.

Extending laterally into the barrel 13 above the check valve 47 is a bore 56, the inner end of which is connected by a passage 57 to the inner end of the bore 26, while the intermediate portion of the bore is connected by a passage 58 to the reservoir 22. A plunger 59 is slidably carried in the bore 56 and is biased outwardly by a coil spring 61. The inner end of the plunger is provided with a pin 62 which has a conical end engageable with a seat or end of a small passage 63 leading from the bore 56 to the passage 57. The valve actuator 17 is pivotally mounted on the barrel 13 by means of a pivot pin 64. At its upper end, it has an adjustable contact screw 65 which engages the outer end of the plunger 59, the other end of the valve actuator being resiliently biased outwardly by a coil spring 66 extending between the lower end of the actuator and the barrel 13. In other words, the spring 66 keeps the contact screw 65 pressed against the plunger 59, so that the stem or pin 62 of that plunger is maintained against the end of the passage 63 under normal circumstances.

Referring to FIG. 11, it can be seen that the squeeze lever 14 is provided with

double walls

67 and 68 in which is held the pivot pin 29. The end of the link 31 is centered between the two walls by

washers

69 and 71. In FIG. 12 it can be seen that the handle 12 is formed of two

plastic elements

72 and 73, outside of which extends

sheet metal elements

74 and 75. The elements are held together by the pivot pin 33 which is in the nature of a rivet.

The operation of the invention will now be readily understood in view of the above description. The blind rivet is mounted on the rivet anvil 16 by passing the mandrel through the bore 41, so that it lies between the jaws 43. The flange on the rivet portion rests against the front portion of the nose or insert 42. The operator holds the rivet gun in a manner similar to a shooting gun and inserts the rivet through the two elements that are to be fastened together. He then squeezes the squeeze lever 14 toward the handle 12 and, through the lever system l8,the piston 36 is moved upwardly in the bore 27. Hydraulic fluid flows up into the vestibule 55 (see FIG. 9) and forces the ball 49 to the right against spring pressure. Oil is allowed to flow around the ball 49 and into the passage 48.to the end of the bore 26. The oil.pressure presses the piston 38 of the secondary piston system to the left carrying the rivet anvil 16 to the left with it. The rivet, including the mandrel, starts to the left, but any slight movement of the mandrel through the jaws 43 causes them to grip it even tighter,

so that it is prevented from moving any distance. The

movement of the nose or insert 42 to the left, however, causes the'head on the mandrel to collapse the free end of the hollow rivet on the other side of the elements which are to be fastened. Upon completion of a stroke of the piston 36, the operator allows the squeeze lever 14 to move back away from the handle grip 12. The coil spring 37 carries the piston back down again. When it does this, suction is created in the bore 27 above the piston and this closes the ball 49, while, at the same time, causing the ball 54 to move to the right against the pressure of the spring 55. This allows oil to travel from the reservoir 22 through the passage 53 around the ball 54 and into the bore 27. Hydraulic fluid is, therefore, available for the next stroke of the piston 36. The operator then squeezes the lever 14 toward the handle grip 12, causing the piston 36 to move upwardly again and introduce a further amount of fluid into the bore 26 to the right of the piston 38. Each time this cycle is repeated, the rivet anvil 16 moves further away from the jaws 43 in the barrel 13. This causes the head on the mandrel to continue to form a flange on the back side of the articles to be riveted together. Eventually, the flange is .formed up against the back surface of these articles in such a way that further operation of the gun no longer results in deformation of the rivet, but only serves to increase the forces in the mandrel greatly. Eventually, these forces reach an amount sufficient to break the mandrel in the customary way and the riveting operation is completed. The loose teeth of the mandrel lie in the passage through the barrel 13 and the release of the forces on the jaws 46 cause them no longer to grasp the mandrel so that it passes backwardly through the plunger and the spring 45 to the rear of the gun. The rivet gun is now ready for another riveting operation.

If, at any time, the operator desires to release the pressure in the gun, it is only necessary for him to move his thumb up and press the bottom end of the valve actuator 17. This causes the plunger 59 to move to the right (FIG. 9) and open the passage 63. This allows the pressure fluid to flow from the bore 26 through the passage 57 into the bore 56 and then through the passage 58 to the reservoir 22. The fact that the piston 24 is spring-loaded by the spring 25 means that the size of the reservoir changes with the amount of fluid in the various parts of the system. The release of pressure from behind the piston 38 allows the spring 46 to retract the piston rod 39 and the rivet handle 16 to the condition shown in FIG. 8. It should be noted that the combination of the plunger 59, the spring 61, the actuator l7, and the spring 66 acts as a relief valve. If the operator attempts to exceed a predetermined pressure (in the preferred embodiment 3000 psi) in the chamber behind the piston 24, the pressure makes itself felt on the plunger 62 through the

passages

57 and 63,. The plunger moves to the right in FIG. 9) and allows fluid to slow into the chamber 56 and through the passage 58 into the reservoir 23. The excess pressure is thus re-. lieved and any danger of damage is removed.

An examination of the invention will show a number of advantages. One is that the pressure brought to. bear on the rivet is completely under the control of the operator, in accordance with the amount he squeezes on the lever 14. By using long strokes of the lever, of course, he increases the flow of fluid and the pressure by large amounts. It is possible by making short strokes to increase the oil pressure and flow in small increments. He would probably want to do this at the time when the mandrel is almost ready to break. Because of the tremendous forces available in this hydraulic system, it is possible to handle large rivets, even as large as 3/16 inch. Nevertheless, it is possible to release the hydraulic pressure built up at any time for safety purposes. It should be noted, incidentally, that the first pumping action of the lever 14 locks the rivet securely in place, so that it is possible to work in overhead locations and to carry the gun from place to place with a rivet securely held in place. The releasing action of the rivet chuck jaws facilitates the removal of the rivet shank or mandrel after the riveting job is finished.

It is obvious that minor changes may be made in the form and construction of the invention without departing from the material spirit thereof. It is not, however, desired to confine the invention to the exact form herein shown and described, but it is desired to include all such as properly come within the scope claimed.

The invention having been thus described, what is claimed as new and desired to secure by Letters Patent 1. A rivet gun for use with a hollow rivet having a mandrel, comprising a. a main body having a hand grip and a barrel,

b. a squeeze lever pivotally attached to the main body adjacent the hand grip,

c. a mandrel grip and a rivet anvil mounted on the free end of the barrel,

(1. a primary piston system carried in the handle and operable by the squeeze lever,

e. a secondary piston system carried in the barrel and connected to the rivet anvil,

f. a reservoir for containing a body of hydraulic fluid,

g. a check valve between the primary piston system and the secondary piston system.

2. A rivet gun as recited in claim 1, wherein the check valve is arranged to allow fluid flow only from the first piston system to the second piston system.

3. A rivet gun as recited in claim 1, wherein a check valve is connected to allow flow of fluid only from the reservoir to the first piston system.

4. A rivet gun as recited in claim 1, wherein a manually-operable valve is mounted to selectively connect the second piston system to the reservoir.

5. A rivet gun as recited in claim 4, wherein the valve is operated by a movable lever mounted externally of the main body in a position such that it can be pressed by the thumb when the hand is wrapped around the grip.

6. A rivet gun as recited in claim 1, wherein the reservoir is expandible.

7. A rivet gun as recited in claim 5, wherein the reservoir consists of a bore in which a piston is slidably mounted, and wherein a coil spring lies between one end of the bore and the piston.

8. A rivet gun as recited in claim 1, wherein the second piston system includes a power bore extending longitudinally of the barrel, wherein the first piston system includes a pump bore extending at a right angle to a second piston system bore, and wherein the reservoir includes a bore aligned with the second piston system bore.

9. A rivet gun as recited in claim 8, wherein the reservoir bore and the power bore are separated by a substantial space, and wherein an imaginary extension of the pump bore passes through the space.

10. A rivet gun as recited in claim 9, wherein the check valve is located in the said space to allow fluid flow only from the first piston system to the second piston system, wherein the space includes another check valve connected to allow the flow of fluid only from the reservoir to the first piston system; and wherein the space includes a manually operable valve to selectively connect the second piston system to the reservoir.

11. A rivet gun as recited in claim 1, wherein the squeeze lever is connected to the first piston assembly by a lever system, wherein the squeezing of the lever toward the hand grip causes a point in the system to move the first piston system.

12. A rivet gun as recited in claim 11, wherein the squeeze lever is provided with a protuberance on the side facing the hand grip, the protuberance having a pivot point which moves parallel to the axis of the pump bore when the squeeze lever is moved toward the handle grip, wherein one end of a first link is pivotally connected to the squeeze lever at the said pivot point, wherein one end of a second link is pivotally connected to the handle grip, the other ends of the links being pivotally connected, the first link being formed with an integral bellcrank arm that extends beyond the pivotal connection of the links and engages a pump piston of the first piston system, and wherein a coil spring concentric with the pump piston is operative to bias the pump piston and the bellcrank arm in the direction to move the squeeze lever away from the hand grip.

13. A rivet gun as recited in claim 1, wherein the secondary piston system includes a power bore extending longitudinally of the barrel and having a piston with a piston rod extending to the end of the barrel and connected to the rivet anvil, the anvil having a bore that is

Claims

1. A rivet gun for use with a hollow rivet having a mandrel, comprising a. a main body having a hand grip and a barrel, b. a squeeze lever pivotally attached to the main body adjacent the hand grip, c. a mandrel grip and a rivet anvil mounted on the free end of the barrel, d. a primary piston system carried in the handle and operable by the squeeze lever, e. a secondary piston system carried in the barrel and connected to the rivet anvil, f. a reservoir for containing a body of hydraulic fluid, g. a check valve between the primary piston system and the secondary piston system.

6. A rivet gun as recited in claim 1, wherein the reservoir is expandible.

10. A rivet gun as recited in claim 9, wherein the check valve is located in the said space to allow fluid flow only from the first piston system to the second piston system, wherein the space includes another check valve connected to allow the flow of fluid only from the reservoir to the first piston system, and wherein the space includes a manually operable valve to selectively connect the second piston system to the reservoir.