US3898833A

US3898833A - Air-hydraulic rivet gun

Info

Publication number: US3898833A
Application number: US460729A
Authority: US
Inventors: Russell F Richardson
Original assignee: Textron Inc
Current assignee: Textron Inc
Priority date: 1974-04-15
Filing date: 1974-04-15
Publication date: 1975-08-12
Anticipated expiration: 1992-08-12

Abstract

A rivet gun of the type for setting blind tubular rivets mounted on a mandrel by tensioning the mandrel to the point of rupture. The rivet gun is characterized by an air actuated hydraulically driven mechanism to grip and retract the mandrel and to eject the mandrel when separated from the rivet. The power unit may be fitted with interchangeable rivet setting heads for either inline ''''straight-on'''' riveting or a 90* angle head to permit use of the gun in otherwise inaccessible places.

Description

United States Patent Richardson 1 Aug. 12, 1975 [54] AIR-HYDRAULIC RIVET GUN 3,410,128 1 1/1968 Sauter 72/391 3,760,627 9 973 R' 7 [75] Inventor: Russell F. Richardson, St. Paul, II xchdrdson 2/39] mn Primary Examiner-C. W. Lanham [73] Assignee: T extron lnc., Providence, R]. Assistant Examiner-Gene P. Crosby 22 Filed: Apr. 15, 1974 [21] Appl. No.: 460,729 [57] ABSTRACT A rivet gun of the type for setting blind tubular rivets mounted on a mandrel by tensioning the mandrel to [52] US. Cl. the Point of rupture- The rivet gun is characterized y [5 6 J an air actuated hydraulically driven mechanism to [58] Field of Search 72/391, and retract the mandrel and to eject the mandml when separated from the rivet. The power unit may be fitted [56] References cued with interchangeable rivet setting heads for either in- UNITED STATES PATENTS line straight-0n riveting or a 90 angle head to per- 3,082,898 3/ 1963 Bosch 72/391 mit use of the gun in otherwise inaccessible places. 3,254,522 6/1966 Elliott 72/39] 3,367,166 2/1968 Newton 72/391 5 Clams, 3 Drawmg Flgul'es 5 7fl [8 5/ {l Z 46 48 7/ $3 32 47 /3 0 3 A n n 11 w I 3 3 U U U PATENTEDAUBlZiSYS 3,898,833 A g mm 5 AIR-HYDRAULIC RIVET GUN This invention relates to a gun for setting blind rivets of the type in which the rivet is both inserted into the work and secured therein from the same side, without access by the operator to both sides of the work. The rivet is set by deformation of the tubular stem of the rivet on the remote side of the work by virtue of expansion of the stem by pulling the head of the mandrel on which the rivet is mounted into the stem and then rupturing the mandrel to free it from the rivet.

Rivets for this purpose and guns for setting such rivets are well known. Both manually operable and power operated guns are available. Heavy duty work and repetitious work over a long period of time, such as on an assembly line, tend to be fatiguing to the operator. The present invention is directed to a power operated rivet setting gun of improved design characterized by an air actuated hydraulically driven mechanism for grasping and retracting rivet mandrels.

The invention is illustrated in the accompanying drawings in which:

FIG. 1 is a side elevation of one form of rivet gun according to the present invention;

FIG. 2 is a front elevation thereof;

FIG. 3 is a rear elevation thereof;

FIG. 4 is a vertical longitudinal section on an enlarged scale showing the operating parts in at-rest position;

FIG. 5 is a similar sectional view showing the parts under air and hydraulic pressure just prior to separation of the mandrel from the rivet head;

FIG. 6 is a fragmentary sectional view on an enlarged scale showing the gun in engagement with a rivet mandrel just prior to separation;

FIG. 7 is a side elevation of another form of rivet gun according to the present invention having a right angle head; and

FIG. 8 is a fragmentary longitudinal section showing details of construction of that angle head.

Referring now to the drawings, and particularly to FIGS. 1 through 6, the rivet gun comprises a power unit, indicated generally at 10, and one form of interchangeable rivet setting head for in-line work, indicated generally at 11. The power unit includes a body having a pistol grip handle portion 12 and an integral air cylinder housing 13. Handle 12 is provided with a recess 14 for receiving a palm grip trigger l5 pivotally held on pin 16. Handle 12 is also provided with a longitudinal passage or channel 17 extending from the free end of the handle into trigger recess 14.

A fitting 18 is inserted into the free end of passage 17 for the purpose of connecting the rivet gun to a source of compressed air or other gas under pressure. A hollow tubular plunger pin 19 is inserted into passage 17 from the trigger recess. A cam 20 on trigger l5 bears against the head of plunger pin 19 which is spring biased by a light coil spring 21 to be normally urged upward into the trigger recess urging the trigger into its at-rest position. A valve disc 22 lies in passage 17 between the inner ends of plunger pin 19 and air fitting 18, normally urged into sealing engagement with annular valve seat 23 by coil spring 24.

When trigger is squeezed, cam bearing against the end of plunger pin 19 compresses spring 21 and causes valve disc 22 to be unseated, compressing spring 24. This permits air to enter through passage 17 into air passage 25 to chamber 26 within air cylinder housing 13. When trigger 15 is released, spring 21 retracts plunger pin 19 and returns the trigger to its at-rest position. At the same time, spring 24 reseats valve disc 22 on seat 23 to shut off the supply of air to the rivet gun. Air bleeding from chamber 26, as explained in detail hereinafter, is forced out through passage 25 into passage 27 and the open end of pin 19 and out through bleeder holes 27 and passage 28 to the atmosphere.

An air ram or piston 29 is disposed in chamber 26 for reciprocal movement therein. The outer perimeter of piston 29 is provided with an annular groove into which is fit a resilient O-ring 30 for sealing engagement with the inside cylinder wall. The air cylinder chamber is closed by means of a cap 31 inserted therein. An annular seal ring 32 is seated in the opposite end of chamber 26 from which a bleed hole 33 permits escape of air from chamber 26 on the operating stroke of piston 29.

An hydraulic cylinder housing 34 is connected to the air cylinder housing. Housing 34 encloses a pair of spaced apart

chambers

35 and 36 interconnected by passage 37 and adapted to contain hydraulic fluid. Hydraulic fluid chamber 35 is in axial alignment with air chamber 26. One end 38 of housing 34 extends through a central passage 39 in air cylinder housing 13 and is rigidly fixed therein by means of a lock nut 40.

An hydraulic ram 41 is rigidly secured to air piston 29 in axial alignment therewith, as by means of nut 42. Ram 41 extends into hydraulic chamber 35 through a restricted passage having a pair of annular grooves therein fitted with resilient seal rings to prevent loss of hydraulic fluid. Upon admission of air into chamber 26 behind air piston 29, the piston and ram 41 are moved forwardly. As ram 41 advances into chamber 35, it pushes the noncompressible hydraulic fluid therein through passage 37 into chamber 36 which overlies chamber 35.

Chamber 36 is closed at one end by means of a back cap 46 to which a deflector 47 is attached by means of a threaded ring or collar 48. An hydraulic piston 49 is disposed in chamber 36 for reciprocal movement therein. The peripheral edge of piston 49 is provided with a groove in which is seated a resilient seal ring 50 held in place by an expansion washer. Piston 49 is provided with a forwardly extending stem 51 and a rearwardly extending stem 52.

The free end of stem 52 fits into a central passage 53 in back cap 46 for reciprocal movement therein. Piston 49 is spring biased by means of a heavy coil spring 54 normally urging the piston to an at-rest forward position adjacent passage 37. Stem 51 extends through a passage in the forward wall of housing 34 sealed against leakage of hydraulic fluid, as by means of a pair of resilient O-rings set in annular grooves in the passage. A central passage 58 extends through piston 49 and its

stems

51 and 52 for ejection of spent mandrels.

A tubular nose housing 59 having an internally threaded base 60 is secured to the externally threaded boss 61 on the forward wall of hydraulic housing 34. The free forward end 62 of hydraulic piston stem 51 is externally threaded and has an adjusting nut 63 and tubular pulling head 64 secured thereon. The forward end of pulling head 64 is externally threaded to receive annular jaw case 65 whose inner tapering walls engage a plurality of mandrel gripping jaws 66. A jaw pusher 67 is disposed within pulling head 64 and jaw case 65 biased by coil spring 68 to maintain force on jaws 66 constantly urging the jaws toward the forward end of the jaw case 65 into engagement with the inner walls thereof.

As seen in FIG. 4, when the parts are in at-rest position with spring 54 holding hydraulic piston 49 in the forward end of chamber36, jaw case 65 bears against the inside forward end of the nose housing. The inner or rearward end of nose piece 69 bears against jaws 66 spreadingthem apart and pushing them inwardly into jaw case 65 pushing jaw pusher 67 rearwardly and compressing spring 68. Jaw pusher 67 has a central passage 70 and nose piece 69 has a central passage 71, both in alignment with passage 58 to receive and eject a mandrel.

As seen in FIG. 6, passage 71 in the nose piece serves as a central bore in which to receive the mandrel 72 of a conventional blind rivet. Such a rivet has a hollow tubular shank or body 74 which extends through the work piece to be riveted (here shown as composed of two plates to be riveted together) and an annular flanged head 75, which may be flat or domed or counter-sunk, and engages the operatorside of the work. The mandrel 72 is inserted through the rivet in the reverse direction, that is, toward the operators side with the head 76 of the mandrel at the opposite end from the head 75 of the rivet. As seen in FIG. 4, when the jaws are spread apart when the mechanism is in at-rest position, the mandrel is easily inserted.

When the rivet gun is connected to a source of air or other gas under pressure and trigger is depressed to move air piston 29 forward, as described above, ram 41 advancing in hydraulic chamber 35 forces the hydraulic fluid therein through passage 37 into chamber 36. As the hydraulic fluid fills chamber 36, it moves hydraulic piston 49 rearwardly compressing spring 54. As piston 49 moves rearwardly, it pulls stem 51 and along with it pulling head 64 and jaw case 65. As the jaw case 65 is drawn backwardly from nose piece 69, force on spring 68 is withdrawn causing it to expand, moving jaw pusher 67 forwardly and causing the jaws to close. This force in combination with the rearward force exerted by the inside tapered surfaces of the jaw case 65 against the jaws 66 forces the jaws into tight gripping engagement with mandrel 72. As the rearwardly directed pulling force continues, the head 76 of mandrel 72 is forced into and expands the outer end of tubular body 74 of the rivet tightening it in place in the work piece and severing the mandrel from the head. The mandrel then may pass rearwardly through

passages

70, 58 and 53. Deflector 47 protects the operator from injury in the event the mandrel is forcefully ejected.

When pressure on the trigger is released, piston 49 is returned to its at-rest position by force exerted by spring 54, returning the pulling head and jaw case to their at-rest positions ready to receive another mandrel. Hydraulic fluid is forced from chamber 36 through passage 37 into hydraulic chamber 35. Ram 41 and air piston 29 are returned to their at-rest positions. Air from air piston chamber 26 is bled to the atmosphere as already described.

Referring now to FIGS. 7 and 8, there is shown a rivet gun with an alternative riveting head 80 for setting rivets in inaccessible places by exerting force at an angle of 90 relative to the direction of force exerted by the power unit. As is explained in further detail hereinafter, angle head 80 is interchangeable with the on-line rivet head 11 previously described, using the same power unit and operating in generally the same manner with the exceptions noted below.

In US. Pat. No. 3,760,627, issued Sept. 25, 1973, of which the present applicant is co-patentee, there is disclosed an angle head rivet gun, the basic structure and operation of which, except for the power source, are generally the same as described herein. The disclosure of that patent is incorporated herein by reference.

The angle rivet setting head comprises a hollow tubular body 82 internally threaded at one end to receive a nose piece 83 having a restricted bore which is likewise internally threaded to receive a bushing 84. Bushing 84 has a central bore in which to receive the mandrel of a conventional blind rivet. A pulling head 89 reciprocates within the hollow body 82. The forward end of pulling head 89 is externally threaded and adapted to receive chuck or jaw case 90 whose bore is tapered to receive a pair of tapered jaws 91 which function to engage the shank of a mandrel. Pulling head 89 has a central bore 92 extending axially through its length. Bore 92 is of reduced diameter at its rearward end providing a shoulder against which one end of a coil spring 94 bears. A tubular sleeve 95 within bore 92 functions as a jaw actuating member, one end of sleeve 95 bearing against jaws 91 and the opposite end bearing against spring 94 to maintain the jaws in constant gripping engagement with the mandrel.

The rearward end of pulling head 89 is of reduced diameter and reciprocates in passage 96 in the rearward end of housing 22 opposite from the nose piece. A heavy coil spring 97 surrounds the reduced diameter end of pulling head 89, one end of spring 97 bearing against a shoulder formed on the pulling head and the other end bearing against an internal shoulder 98 within the body. As illustrated in the aforesaid patent, the opposite sides of the pulling head are flattened to provide a pair of recesses, each having a rearward shoulder against which a cam 99 of a cam arm lever 100 bears.

Angle head 80 includes an elongated tubular housing 101, the upper end of which is fixed in a tubular sleeve 102 disposed at right angles to the longitudinal axis of housing 82 and having an opening 103 therein. Tubular housing 82 is provided with an opening 104 about midway between its ends. A pair of parallel spaced apart gusset plates 105 generally enclose the space between

openings

103 and 104. A pair of parallel spaced apart crank arm levers 100 are pivotally supported between the gusset plates on a pin 106. Cam arm 99 extends through opening 104. Cam arm 107 extends through opening 103 embracing the sides of pulling shaft 108 and engaging pin 109 extending transversely through the pulling shaft. The opposite end of pulling shaft 108 is threaded and provided with a coupling nut or threaded sleeve 110 by which the pulling shaft is connected to the threaded end of stem 51 of hydraulic piston 49.

In order to hold the pulling shaft against rotation within tubular body 101 to permit this connection to be made, pin 109 is of sufficient length that its ends extend into slots 1 1 1 formed in sleeve 102. For safety reasons, the ends of pin 109 may be received in a pair of internal longitudinal grooves formed in the sleeve, or a protective cover may be snapped over the slot area. Tubular body 101 is internally threaded at l 12 to permit attachment of the angle head to the power unit by screwing onto threaded boss 61. Sleeve 102 is freely rotatable on ference is that the pulling force exerted by piston 49 is transmitted to pulling shaft 108. Pin 109 bearing against cam arm 107 causes crank arm 100 to rotate on its pivot. This translates the pulling force through 90, causing cam arm 99 to exert pulling force on pulling head 89. Thereafter the operation is the same as already described in connection with the in-line head. Although the angle rivet setting head is described and illustrated as being disposed at a right angle relative to the axis of the pulling force exerted by the power unit, the head may be disposed at an angle other than 90 with only minor modification of the levers 100 and their supporting structure.

It is apparent that many modifications and variations of this invention as hereinbefore set forth may be made without departing from the spirit and scope thereof. The specific embodiments described are given by way of example only and the invention is limited only by the terms of the appended claims.

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

1. A rivet gun for setting blind rivets, said gun comprising:

A. a setting head for engaging and pulling the mandrel of a blind rivet,

B. a body including force exerting means for applying pulling force to said setting head, the direction of said force being generally longitudinal of said body,

C. said force exerting means comprising 1. a first hydraulic pressure chamber within said body having a piston reciprocable therein generally longitudinally of the body,

2. stem means movable with said piston in the same direction,

3. means connecting said stem means to the setting head to operate the same,

4. a second hydraulic pressure chamber disposed within said body in parallel closely spaced apart relation to the first chamber, said chambers being connected through an intercommunicating passage within said body,

5. a piston reciprocable in said second chamber,

6. a third pneumatic pressure chamber within said body in axial alignment with said second chamber,

7. a piston reciprocable in said third chamber and connected to the piston in said second chamber for simultaneous movement thereof,

8. means adapted to connect said third chamber to a source of gas under pressure, and

9. means to regulate flow of gas to said third chamber,

D. a pistol grip handle on said body adjacent to said third chamber.

2. A rivet gun according to claim 1 further characterized in that said setting head is replaceable and interchangeable with other setting heads and includes a tubular housing detachably secured to said body and a reciprocable pulling head within said housing detachably secured to said piston stem,

A. said pistion stem extending from said body through a coaxial passage in an externally threaded boss on the exterior of the body,

B. said setting head housing being internally threaded for attachment thereto,

C. said piston stem being extemally threaded at one end, and I D. said pulling head being internally threaded for attachment thereto.

3. A rivet gun according to claim 1 further characterized in that said setting head is secured to said body with the longitudial axis of said setting head disposed at an angle relative to the longitudinal axis of said body and the direction of force applied by said force exerting means.

4. A rivet gun according to claim 3 further characterized in that said setting head is replaceable and interchangeable with other setting heads and includes:

A. an elongated tubular housing internally threaded at one end, the longitudinal axis of said tubular housing being in alignment with said body and the direction of force applied by said force exerting means and attached to said body through an externally threaded boss on the exterior of said body surrounding a passage coaxial with said piston stem,

B. a tubular setting head housing secured to the opposite end of said elongated tubular housing, the longitudinal axis of said setting head being disposed at an angle relative to the longitudinal axis of said elongated tubular housing,

C. a pulling shaft disposed within said elongated longitudinal housing and detachably secured at one end to said piston stem; and

B. pivotal crank arm lever means interconnecting said pulling head and said pulling shaft for transmission of force from said pulling shaft to reciprocate said pulling head.

5. A rivet gun for setting blind rivets, said gun comprising:

A. a setting head for engaging and pulling the mandrel of a blind rivet,

B. a body including force exerting means for applying pulling force to said setting head, the direction of said force being generally longitudinal of said body and setting head, said force exerting means comprising l. a first hydraulic pressure chamber within said body having a piston reciprocable therein generally longitudinally of the body,

2. externally threaded stem means movable with said piston in the same direction and extending from said body through a coaxial passage in an externally threaded boss on the exterior of the body,

3. a second hydraulic pressure chamber disposed within said body in parallel closely spaced apart relation to the first chamber, said chambers being connected through an intercommunicating passage within said body,

4. a piston reciprocable in said second chamber,

5 a third pneumatic pressure chamber within said body in axial alignment with said second chamber, and

6. a piston reciprocable in said third chamber and connected to the piston in said second chamber for simultaneous movement thereof,

C. an internally threaded tubular setting head housing detachably secured to the externally threaded boss on said body,

D. a reciprocable internally threaded pulling head within said housing detachably secured to said piston stem,

E. a longitudinal axial passage extending through said setting head. the piston in said first chamber, the stern thereof and said body for passage of used rivet mandrels therethrough,

sage means.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3 ,898 ,833 v DATED August 12 1975 |Nv 0R(5) Russell P Richardson It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, line 8, "27" should be 17-.

Column 3, line 22, "operator'side" should be -operator's side-- Column 5, line 25, "privelege" should be privi1ege.

Signed and Sealed this twenty-eight Day Of October 1975 [SEAL] A ttes t:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner uflarents and Trademarks

Claims

1. A rivet gun for setting blind rivets, said gun comprising: A. a setting head for engaging and pulling the mandrel of a blind rivet, B. a body including force exerting means for applying pulling force to said setting head, the direction of said force being generally longitudinal of said body, C. said force exerting means comprising 1. a first hydraulic pressure chamber within said body having a piston reciprocable therein generally longitudinally of the body, 2. stem means movable with said piston in the same direction, 3. means connecting said stem means to the setting head to operate the same, 4. a second hydraulic pressure chamber disposed within said body in parallel closely spaced apart relation to the first chamber, said chambers being connected through an intercommunicating passage within said body, 5. a piston reciprocable in said second chamber, 6. a third pneumatic pressure chamber within said body in axial alignment with said second chamber, 7. a piston reciprocable in said third chamber and connected to the piston in said second chamber for simultaneous movement thereof, 8. means adapted to connect said third chamber to a source of gas under pressure, and 9. means to regulate flow of gas to said third chamber, D. a pistol grip handle on said body adjacent to said third chamber.

2. stem means movable with said piston in the same direction,

2. A rivet gun according to claim 1 further characterized in that said setting head is replaceable and interchangeable with other setting heads and includes a tubular housing detachably secured to said body and a reciprocable pulling head within said housing detachably secured to said piston stem, A. said pistion stem extending from said body through a coaxial passage in an externally threaded boss on the exterior of the body, B. said setting head housing being internally threaded for attachment thereto, C. said piston stem being externally threaded at one end, and D. said pulling head being internally threaded for attachment thereto.

3. means connecting said stem means to the setting head to operate the same,

4. a piston reciprocable in said second chamber, 5 a third pneumatic pressure chamber within said body in axial alignment with said second chamber, and

4. A rivet gun according to claim 3 further characterized in that said setting head is replaceable and interchangeable with other setting heads and includes: A. an elongated tubular housing internally threaded at one end, the longitudinal axis of said tubular housing being in alignment with said body and the direction of force applied by said force exerting means and attached to said body through an externally threaded boss on the exterior of said body surrounding a passage coaxial with said piston stem, B. a tubular setting head housing secured to the opposite end of said elongated tubular housing, the longitudinal axis of said setting head being disposed at an angle relative to the longitudinal axis of said elongated tubular housing, C. a pulling shaft disposed within said elongated longitudinal housing and detachably secured at one end to said piston stem; and B. pivotal crank arm lever means interconnecting said pulling head and said pulling shaft for transmission of force from said pulling shaft to reciprocate said pulling head.

5. A rivet gun for setting blind rivets, said gun comprising: A. a setting head for engaging and pulling the mandrel of a blind rivet, B. a body including force exerting means for applying pulling force to said setting head, the direction of said force being generally longitudinal of said body and setting head, said force exerting means comprising

5. a piston reciprocable in said second chamber,

6. a piston reciprocable in said third chamber and connected to the piston in said second chamber for simultaneous movement thereof, C. an internally threaded tubular setting head housing detachably secured to the externally threaded boss on said body, D. a reciprocable internally threaded pulling head within said housing detachably secured to said piston stem, E. a longitudinal axial passage extending through said setting head, the piston in said first chamber, the stem thereof and said body for passage of used rivet mandrels therethrough, F. a pistol grip handle on said body adjacent said third chamber, G. passage means in said handle for passage of gas under pressure to the third chamber and bleeding of gas from said chamber to the atmosphere, and H. trigger actuated valve means in said handle for alternately controlling flow of gas through said passage means.

9. means to regulate flow of gas to said third chamber, D. a pistol grip handle on said body adjacent to said third chamber.