US3543560A - Rivet tool - Google Patents

Description

Dec. 1, 1970 F. J. HARRIS RIVET TOOL Filed Jan. 4. 1968 EM 0 4 MJ Mm K C E f m W J m United States Patent G 3,543,560 RIVET TOOL Frederick J. Harris, Ansonia, Conn., assignor to Olin Mathieson Chemical Corporation, a corporation of Virginia Filed Jan. 4, 1968, Ser. No. 695,759 Int. Cl. B21d 9/05 US. Cl. 72-391 2 Claims ABSTRACT OF THE DISCLOSURE A rivet tool for use in setting tubular rivets mounted on a mandrel wherein the housing of the tool has a detachable nose piece with a mandrel gripping pawl positioned therein.

This invention relates generally to a rivet tool. More particularly, this invention relates to a riveting tool of the type employed for setting blind rivet assemblies wherein the riveting forces are all applied from one side of the workpiece.

Tools of the above type are used to set a rivet assembly which includes an elongated mandrel having an enlarged head portion at one end and a gripping portion at the other. A rivet is positioned on the mandrel with its tail portion adjacent the head of the mandrel and its head portion positioned adjacent the gripping portion. Such tools and rivet assemblies are used in many different operations wherein it is desired to fasten two members together.

Such tools may include a pulling head adapted to be attached to an actuator which is energized pneumatically, hydraulically, electrically, or otherwise. The pulling head of one typical design includes a housing member having a drawbolt with an attached collet positioned therein for axial movement by the actuator. A plurality of jaw members are floatingly positioned within the collet with a spring biased follower urging them into their gripping position.

It is an object of the present invention to provide an improved riveting tool.

More particularly, it is an object of the present invention to provide a riveting tool having an interchangeable nosepiece to accommodate rivet assemblies of different sizes.

Another object of this invention is to provide a riveting tool wherein the nosepiece is provided with means for preventing a rivet assembly from falling out during the time the tool is moved into the position.

Still another object of this invention is to provide a riveting tool including improved means for preventing the ejection of a spent mandrel forwardly out of the tool.

More specifically, it is yet another object of this invention to provide an improved riveting tool wherein the mandrel retaining means is prevented from snagging.

A further object of this invention is to provide a riveting tool having mandrel retaining means which aids in the ejection of a spent mandrel.

These and other objects of the invention may be more readily understood by reference to the following description of a preferred embodiment and to the accompanying drawings in which:

FIG. 1 is a sectional view of a pulling head constructed in accordance with the principals of the present invention;

FIG. 2 is a transverse sectional view taken along the lines 22 of FIG. 1;

FIG. 3 is a partial sectional view taken along the lines 3-3 of FIG. 2; and

FIG. 4 is a partial sectional view similar to FIG. 1, but showing the tool acting upon a rivet assembly with the component parts shown in their respective positions immediately before the mandrel of the rivet assembly snaps.

Referring now to the drawings, the numeral 2 designates a riveting tool constructed in accordance with the present invention which is operable by an actuator 4 (outlined in phantom) of any suitable type which may be energized pneumatically, hydraulically, electrically, or otherwise. As shown in FIG. 4, the riveting tool may be used in conjunction with a rivet assembly 6 which includes a tubular rivet 8 mounted on a mandrel 10. The mandrel 10 includes a gripping portion 12 and an enlarged head portion 14. The head portion 14 is connected to the gripping portion 12 by a weakened portion 15. The tubular rivet 8 includes an enlarged head portion 16 which is positioned adjacent the gripping portion 12 of the mandrel 10 and an elongated tail portion 18 terminating at the head portion 14 of the mandrel 10.

Considering the rivet tool 2 itself, it includes an outer tubular housing 20 having drawbolt means 22 disposed within for relative axial movement. The drawbolt means 22 include a drawbolt 24 having a collet 26 threadedly attached to the forward end thereof. Jaw members 28 are positioned within the collet 26 and are urged forwardly into their gripping position by a jaw follower 30 which is biased by a spring 32.

The rearward portion of the housing 20 is externally threaded so that the actuator 4 may be attached thereto. The rearward end of the drawbolt 24 is internally threaded as shown at 34 to receive the externally threaded pulling rod 38 (shown in phantom in FIG. 1) of the actuator 4.

The forward end 40 of the drawbolt 24 is provided with a bore 42 which receives the jaw follower 30. The jaw follower 30 is provided with an axially extending bore 44 which communicates with an axially extending groove 46 in the drawbolt 24. The housing 20 is provided with a slot 48. The slot 46 in the drawbolt 24 is held in alignment with the groove 48 in the housing 20 by means of a detent 50 in the housing 20 which extends into a longitudinal groove 52 in the outer surface of the drawbolt 24. The rearward end 53 of the groove 48 is curved to facilitate the removal of the mandrel 10 after it breaks.

The jaw members 28 are floatingly positioned within the collet member 26. The outer surface of each of the jaw members 28 includes a tapering portion 54 having a taper corresponding to the taper of the forward internal surface 56 of the collet member 26. The inner surface of each of the jaw members 28 is provided with mandrel gripping teeth 58.

The jaw follower 30 is positioned rearwardly of jaw members 28 within collet member 26 and includes a rearward extension portion 60 extending through the bore 42 in the forward end of the drawbolt 24. The follower spring 32 is positioned between the forward face of the drawbolt 24 and a flange 62 on the jaw follower 30 to urge the jaw follower, as well as the jaw members 28, forwardly within the collet member 26. The forward end 40 of the drawbolt 24 is provided with a counterbore 64. A buffer member 66 is positioned in the counterbore 64 and extends slightly forwardly from the drawbolt 24. The buffer member 66 is preferably of elastomeric material and is cylindrical in shape. The jaw follower 30 is provided with a shoulder 68 for abutment with the forward face of the buffer 66 upon relative rearward movement when the mandrel breaks.

The forward end of the tubular housing 20 is internally threaded for the reception of an interchangeable nosepiece assembly 70. The nosepiece assembly 70 consists of a tubular member 72 which is externally threaded to coincide with the internal threads in the housing 20. A flange 74 is provided on the member 72 to limit the inward movement of the nosepiece assembly 70. The

forward face 76 of the member 72 provides a bearing surface to resist the riveting setting forces. The member 72 is provided with an axially extending bore 78 for reception of the rivet mandrel. A boss '80 projects axially rearwardly from the tubular member 72 and is in alignment with the bore 78. The rearward surface 82 of the boss 80 is tapered outwardly in a forward direction to mate with the corresponding tapered forward surfaces 84 of the jaw members 28.

The member 72 is provided with a counterbored hole 86 which is perpendicular to the axis of the bore 78. A mandrel retaining pawl 88 is mounted within the hole 86 and includes a flange 90 adapted to abut against the shoulder 92 formed by the counterbore, whereby inward movement of the retaining pawl 88 is limited. The retaining pawl 88 is generally cylindrical in shape and has its inner end 91 tapered away from the axis of the bore 78 in a direction forwardly of the tool so that the surface of the mandrel retaining pawl 88 which is closest to the jaw members 28 extends into the bore 78 of the nosepiece 70, the greatest distance. An annular groove 94 extends about the tubular member 72 and passes within the diameters of the counterbored hole 86. A resilient ring 96 is mounted within the groove 94 and also passes through a groove 98 in the outer surface of the mandrel retaining pawl 88 to urge the pawl 88 inwardly toward the axis of the bore 78. The resilient ring 96 may be fabricated from any suitable material such as neoprene, elastomeric materials, as well as metal in the form of a garter spring.

In operation, a nosepiece 70 of the proper size for use with the size of the mandrel of the particular rivet assembly to be used is attached to the forward end of the housing 20. The proper size nosepiece 70 will have a bore 78 slightly larger than the diameter of the mandrel of the rivet assembly so that there is suitable clearance between the walls of bore 78 and the mandrel 10.

In the loading position of the tool as shown in FIG. 1, the drawbolt assembly 22 has been moved forwardly in the housing 20 until the forward end of the collet member 26 abuts the tubular member 72. In this position, the boss 80 on the tubular member '72 extends into the collet member 26 and engages the forward surface 84 of the jaw members 28 and urges them rearwardly in the collet member 26 against the bias of spring 32. Due to the taper of the forward surfaces 84 of the jaw members 28' and of the rearward surface 82 of the boss 80, as well as the taper of the outer surface 54 of the jaw members 28 and the internal tapered surface 56 of the collet member 26, the jaw members will be moved rearwardly and outwardly whereby the spacing between the mandrel gripping teeth 58 will be sutliciently enlarged to receive the mandrel 10 of the rivet assembly. It will thus be appreciated that the length of the boss 80 of a particular nosepiece governs the maximum diameter of the mandrel 10 that may be inserted. With a smaller bore 78 the boss 80 will not need to be as long as in the case of a larger diameter bore since it will not be necessary to expand the jaw members 28 as far apart.

As the mandrel 10 of the rivet assembly is inserted into the bore 78, it abuts the tapered end 91 of the mandrel retaining pawl 88 and urges the pawl '88 outwardly. As the tension of the ring member 96 increases as the retaining pawl 88 moves outwardly, the increased tension results in a greater force being applied to the pawl member 88 in an inward direction. Thus, after the mandrel 10 is completely inserted in the bore 78 to the point where the head portion 16 of the rivet 8 abuts the forward face 76 of the nosepiece 70, the pawl member 88 will engage the mandrel 10 with sufficient force to retain it in place regardless of the position of the tool.

With the mandrel 10 properly positioned so that the gripping portion 12 thereof extends up into the area between the jaw members 28, the actuator 4 may be operated so that the rod member 38 thereof pulls the drawbolt means 22 rearwardly within the housing 20. This rearward movement permits the jaw follower spring 32 to urge the jaw members 28 radially inwardly along the corresponding tapered surface 56 of the collet 26 and into gripping engagement with the mandrel 10. Continued rearward movement of the drawbolt means 22 results in the entire mandrel 10 being moved rearwardly relative to the tubular rivet 8 so that the head portion 14 of the mandrel 10 is pulled into the tail portion 18 of the rivet and tends to expand it as shown in FIG. 4. Further rearward movement of the darwbolt means 22 results in the snapping of the mandrel 10 at the weakened portion 15. The rearward movement of the broken mandrel continues until the forward end thereof is positioned rearwardly in the tool relative to the retaining pawl 88. At this point, the pawl member can then move inwardly and block off a portion of the bore 78 in the nosepiece 70. When the drawbolt begins to return to its loading position, the forward end of the broken mandrel will abut the pawl member 88 due to the fact that the surface of the mandrel 10 which is closest to the jaw members 28 extends into the bore 78 of the nosepiece 70 the greatest distance. This will prevent any further forward movement of the broken mandrel so that as the drawbolt assembly 22 continues its forward motion, the jaw members will move rearwardly within the collet 26 and spread apart until they lose their gripping hold on the mandrel 10'. Thus, it can be seen by virtue of the particular mandrel retaining means, the gripping action of the jaws 28 on the mandrel 10 is released prior to the jaw members contacting the boss 80 of the nosepiece assembly 70. This results in a faster ejection of the spent mandrel 10, thereby speeding up the entire riveting operation.

By virtue of the above-described arrangement, a riveting tool is provided wherein nosepieces can be interchanged for use with a given size rivet assembly. Moreover, the above-described arrangement of the mandrel retaining means insures that the mandrel will be held in position prior to the rivet setting operation regardless of the position in which the tool is held, as well as preventing the ejection of a spent mandrel through the forward end of the tool after the rivet setting operation. In addition, the mandrel retaining means also serves to help release the gripping action of the jaw members on the mandrel to speed up the rivet setting operation. A further advantage of the invention resides in the fact that the mandrel retaining means is located within the interchangeable nosepiece so that when the nosepiece is connected to the housing, the mandrel retaining means is shielded by the housing preventing damage or snagging during use.

It is to be understood that various other modifications and alterations will readily suggest themselves to persons skilled in the art. It is intended, therefore, that the foregoing description of a preferred embodiment be considered as exemplary only and that the scope of this invention be ascertained from the following claims.

What is claimed is:

1. In a rivet tool for use with a rivet assembly including a breakable mandrel having an axially spaced tail flaring means and grippable means and which includes a tubular rivet on said mandrel having a tail portion adjacent the tail flaring means and a head portion adjacent the grippable means, the combination of axially elongated housing means, a removable nosepiece attached to the forward end of said housing means and having an axially extending mandrel receiving bore therethrough, drawbolt means positioned within said housing means, jaw means within said drawbolt means operable to engage a mandrel upon rearward movement of said drawbolt means relative to said housing means, said nosepiece having a transverse opening communicating with said axial bore and a circumferential groove in its outer surface intersecting said transverse opening, a pawl member mounted in said transverse opening and having its inner end tapering outwardly and forwardly so that the surface of the pawl member closest to the jaw means in an axial direction is adapted to extend into the bore the greatest distance, a groove in the outer face of said pawl member, said groove having a midplane coincident with the midplane of the groove in said nosepiece, a resilient ring extending about the groove in said nosepiece and positioned in said groove in said pawl member, and stop means for limiting the inward movement of said pawl means toward said bore, said stop means including outwardly facing shoulder means in said transverse opening and inwardly facing shoulder means on said pawl member.

2. The rivet tool of claim 1 wherein the outer portion of said transverse opening is counterbored to form said outwardly facing shoulder means and said pawl member includes a generally cylindrical body having a flange at its outer end to provide said inwardlly facing shoulder means.

References Cited UNITED STATES PATENTS CHARLES W. LANHAM, Primary Examiner G. P. CROSBY, Assistant Examiner

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