US2466811A - Method of riveting - Google Patents

Description

April 12, 1949- l.. c. HucK 2,466,811

METHOD oF nIvETING April 12,` 1949. L. c. l-lucKl 2,466,811

METHOD OF RIVETING Filed April so, 1945 2 sheetssheet 2 Patented Apr. 12, 1949 METHOD F RIVETING Louis C. Huck, Grosse Pointe, Mich., assigner, by mesne assignments, to Huck Manufacturing Company, Detroit, Mich., a corporation of Michigan Application April 30, 1945, Serial No. 591,052

The invention relates to riveting mechanisms,

and it has particular relation to a method of setting a two-part rivet.

In setting a blind rivet, as for instance the -brazier head type disclosed in my copending apfactors which tend to extrude the tubular member axially ahead of the shoulder particularly if more metal is ahead of the shoulder than that needed to fill the opening or hole. This extrusion when it occurs may cause an extrusion rise of the brazier head so as to leave a space between the head and structure, or if the plate next to the head moves with the extrusion and hence, moves with the head, the plates may separate to some extent.

After the movement of the shoulder to ll the opening or hole, a head on the pin moves against y the end of the tubular member opposite the brazier head and forms the blind head. Thereafter increased pull on the pin causes a secondary anvil to force a locking collar on the brazier head into a recess in the latter and a recess in the pin, so as to lock the pin and tubular member together. Then continued increase in pull on the pin causes it to break under tension.

Another object of the invention is to provide a method of riveting which will effect return of the radially outer part of the head on the tubular member in the event of an extrusion rise thereof as mentioned.

Other objects of the invention will become apparent from the following specification, from the drawings relating thereto, and from the claims hereinafter set forth.

For a better understanding of the invention reference may be had to the drawings wherein:

Figure 1 is a cross-sectional view illustrating a rivet in its unset condition association with a riveting mechanism constructed according to one form of the invention; and,

Figs. 2, 3, and 4 are similar v iews showing the v rivet in intermediate stages of the riveting oper- 'Il' having openings I2 and I3 for receiving the rivet. The rivet comprises a tubular 'member extending through the openings I2 and I3 and having a preformed or manufactured head I5 engaging the outer side of plate I I, and the underside of this head has a recess I6 adapted to allow for any burrs around the plate opening. Within the openings I2 and I3, the tubular body is of smaller internal diameter as indicated at I'I and at the outer side of plate III, a projecting portion I8 of larger internal diameter is provided. The junction of the two portions I1 and I8 is formed with an annular, conical shoulder I9.

The head I5 shown is of the brazier type and is provided with a central, conical recess 20 which joins a smaller counterbore or recess 2l at its inner end. An annular locking collar 22 axially aligned with the Irecess 20 is initially joined to the head I5 by means of a web 23, and this collar before the rivet is set, projectsaxially outwardly from the surface of the head.

The second part of the rivet comprises a pin having a conical shoulder 25 which engages the shoulder I9 in the tubular member, and when the pin is pulled through the tubular body, the shoulder 25 causes radial expansion of the portion II of the body so as to iill the openings I2 and I3. It might be noted that the largest diameter of the shoulder 25 is approximately equal to or slightly less than the diameter of counterbcre 2l, and also that it is less than the inside diameter of the body portion I8 so that a portion of the shoulder I9 remains after the shoulder 25 has been pulled through the body. The pin also includes an annular relatively deep breakneck or groove 21 which is the weakest part of the pin and a second groove 28 of slightly larger diameter which is adapted to receive the collar 22 in a later part of the riveting operation.

A head 29 on the end of the pin is adapted to engage and move the end of the body portion I8.

so as tocause the latter to bulb outwardly and form what is known as the blind head. It might be mentioned here'that the outer end of the body portion I8 is inherently stronger so as to cause it to remain in unexpanded condition and thereby assure bulbing of the portion I8 between the plate III and such strengthened end, and the manner in which the end of the body portion I8 is strengthened is more particularly. set forth in the copending application for patent previously identiiied. The pin also includes a shoulder SII which is adapted to engage that remaining part of shoulder I9 in the iinal stage of forming the blind or bulbed head from the body portion I8 so as to cooperate in limiting further movement of the pin through the body.v

The rivet is adapted to be set by a rivet setting mechanism which includes aprimary anvil 32 having a concave surface 33 for engaging the radially outer portion of the brazier head I5, but towards its center the anvil is relieved by a reversely curved face 34 and a counterbore formed by an axial-wa ll 35 and a radial wall 3B. The purpose offthis relief in -the anvil and the wall or bottom 3i of the counterbore will be presently considered.

The secondary anvil is indicated at 31 andis adapted to force the collar 22 into the recess 20 in a later part of the riveting operation. The riveting mechanism also includes jaws 38 shown by Fig. 4 for gripping the outer grooved end of the pin indicated at 33 and pulling it in the direcl, heador with a less ductile metal in the head, the

tion of the arrow as shown on the-pin, and the reaction to this pull is applied successively to the anvils 32 and 31 in the opposite ldirection, as also shown by arrows. Details of a gun or riveting mechanismhaving two anvils are mentioned infthefcopending application for patent.

In setting the rivet the pin is gripped and pulled in the direction of the arrow on the pin, and this causes the shoulder. 25 initially to expand the body portion I1 so as to ll the openings in the; structure, and while this is occurring, the reaction'force is applied `by the anvil 32 to the head I5. `iis the shoulder 25 advances through the thicker wall portion I1 of the tubular body, it forces the metal outwardly to fill the openings, and it is desirable that there be sumcient metal to fill the openings. In order to assure obtaining this result even though initial hole clearance around the rivet may vary. the wall portion I1 is made thick enough to provide s'uiiicient hole filling metal for the larger'clearances which may occur in the usual range ofpvariations in hole clearance. It follows from this that there may usually be a surplus of metal over and above thatv required to fill the hole. Hence, it will be found where there is surplus metal that the shoulder 25 in moving'through .the tubular body portion I1 actually will cause the body portion ahead o f the shoulder to flow, and this will cause 'a rise of headl I5 in the same direction as the shoulder is moving so as to move it slightly away from the plate II as shown in Fig. 2.. This extrusion rise of head I5 will occur even though the anvil 32 is applying the reaction force to the head. In other words as' the conical shoulder expands the hole filling portion of the body, the holel ls rst filled,- and then 4during further movement of the shoulder its tapered or conical surface will apply powerful expanding forces to the inside wall of the body due to the -powerful force effective through the tapered engagement. With the hole filled this forceacts with suiiicient power to kelongate thebody ahead of the shoulder and to cause the head I5. to rise above the plate II and to move the-anvil with it. The shoulder25 may finally carry a small amount of metal with it into the counterbore 2l but such metal will be ironed out against the wall of the counterbore. Thus, the counterbore provides a space for such metal and prevents. its movement into the locking recess 20.

The present invention is' particularly concerned with returning or bending the radially outer part of the head I5 into contact `with the plate II after such elongation rise, and also bringing theplatestogether if they have been separated by the elongation` However, -due to the fact the blind head yet must be formed, it is necessary that the. tubularbody be held against movement in the openings in the platesias the yh easi 23 .on

metal and dimensions in the shank remaining the same the counterbore or wall 3l in the anvil must be increased in diameter to provide a greater moment arm, and with a thinner head or more ductile metal'in the head, the counterbore and wall 36,. must be reduced in diameter. From another point of view, the engagement between the anvil and head must be so related to the thickness of head and deformability of the metal of the head relative to the collapsabiiity of the shank as to prevent bending of the radially outer part of the head towards' the plate II prior to formation of the blind head because if the head bends before the blind head is formed',` its pushing against .the plate 'might push them along the shank toward the head 28 and, of course, preventionl of such movement relative to the body is important.

With the anvil 32 now holding the head I5 as 4seen in4 Fig. 2, the head 25 on the pin moves I9 on the tubular member andv this engagement the anvil 32 is provided so as to limit or stopin commotion with the engagement between the head 23 on the pin and the blind head effectively stops. further movement of the pin, at least to any appreciable extent. lWith this increase in resistance toppln movement, the pull on the pin increases4 and consequently the reaction vagainst anvil 32 increases. It follows that more and more pressure is applied against the radially outer portion of head I5 and until the anvil bends or moves the radially outer part of the head towards the structure as seen in Fig. 4. This brings the plates together and also closes any gap between the head and plate II except for lthe recess I6 which, remains and which in fact is slightly deeper due to the extrusion rise of head I5.

Following this bending or movement of the radially outer part of head I5, further increase in pull on the pin, and the reaction applied against head I5 by anvil 32 will automatically cause the reaction to the pull on the pin to shift to the secondary anvil 31, and this anvil then forces the collar 22 into the recess 20 in head I5. At the time the collar is thus forced into the recess 20, the groove 28 is radially aligned with recess 2B and. the collar is forced into the locking groove also, and thus. the pin and tubular member are locked together within the head I5. After this lock is obtained tension on the pin will further increase until it is suiiicient to break the pin-at the breakneck 21. It may be noted here that the pin pulling forces progressively increase through the hole filling, blind head forming, head bend-` ing. collar locking and pin breaking operations.

The wall or bottom 38 in the counterbore in any extrusion of the inner part of the head I5 ,into the counterbore in the event .such movement should occur under certain circumstances. For. example, in viewof manufacturing tolerances and variations in theA metal or other variables, the condition may at some time occur where the head I after the hole filling operation would bend over against the plate II, before the blind head forms In that case. the tubular body might be pulled with the 'pin by the engagement of the head 30 on the pin with the end of the tubular member but if this occurs the wall 36 of the counterbore would positively limit the movement. This insures that the projecting portion I8 of the body will not be appreciably shortened and that continued pull on the pin will form a blind head Particularly where the thickness of the plates approaches the maximum of the range of thickness for any given length of tubular memberv it is important that the projecting body portion I8 not be shortened appreciably since suflicient length of projection must be maintained in order to form a satisfactory blind head.

Normally therefore. where there is surplus metal ahead of the hole filling shoulder 25, an extrusion rise of head I5 may occur and the head will carry the anvil with it due to the extrusion forces. Then when the head 30 on the pin begins to move the end of body portion I8, the relation between the anvil and head I5 is such as to prevent movement of the tubular member throughl thc structure, and the head is not bent by the anvil until the blind head is formed. Normally then. it is only after the blind head forming operation that the forces applied by the anvil be- What is claimed is:

The method of setting a rivet of a type including a tubular member having a centrally opened preformed head at one end, an intermediate body portion and an opposite end portion of larger inside diameter than the inside diameter of said intermediate portion anda pin extending through the tubular member and having a shoulder engaging the intermediate body and having means on one end initially spaced from but designed for engaging said end portion of the tubular member, which comprises inserting the assembled rivet and pin into openings in a structure to be riveted with the intermediate portion in said openings, with the preformed head abutting one face of the structure and with said opposite end portion protruding beyond the structure, pulling the pin and applying the reaction force to the preformed head so as to form a blind head on the opposite end of the rivet, and then applying a substantially entirely axially directed force to an annular area extending radially outwardly from substantially the mid point between the outer surface of the stem and the outer annular edge of the -head to force the radially outer portion only of the head towards and against the structure.

LOUIS C. HUCK.

REFERENCES CITED The following references are of record in the iile of this patent:

UNITED STATES PATENTS Name Date Huck Sept. 8, 1936 Huck Nov. 24, 1936 Huck --a Apr. 19, 1938 Lees Mar; 13,1945 Fischer Mar. 5, 1946 Huck Mar. 26, 1946 FOREIGN PATENTS Country Date France June 7, 1937 .Number Number

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