US3445870A - Piercing and slotting of drive rivets - Google Patents

Description

Maly 27, 1969 Tar. KQLEC.

PIERCING AND SLOTTING 0F DRIIVE RIVETS.

Filed March 27, 1967 ///@Z @WQW \\wm N, -,w m S /W :i M um @N N ww MSN mw Mm y///Mj QQN r S QN K mw A;

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PIERCING AND SLOTTING OF DRIVE RIVETS Filed March 27. 1967 mw .ww Q wm mm NRM wm ww. ww Mm M m mw w f .Wl -llls f f \\\\\\\v lfww@ x x V y? /rlv/ MWQNNV mm m@ wm @www am wm mm @w mm mwmmwwf@ am a NQ, s www E mw wm mm United States Patent O 3,445,870 PIERCING AND SLOTTING F DRIVE RIVETS Robert F. Koiec, Whittier, Calif., assignor to Olympic Screw & Rivet Corporation, Downey, Calif., a corporation of California Filed Mar. 27, 1967, Ser. No. 626,307 Int. Cl. B21k 1/58 U.S. Cl. -20.5 9 Claims ABSTRACT 0F THE DISCLOSURE Forming of drive rivets in progressive four-blow headers of the four-die type with a set of dies which progressively pre-form a length of malleable metal stock in the first die (by a rst blow) into a blank with an upset head having an end socket, final-form said head while deepening said socket in a second die I(by a second blow), form a plurality of longitudinal slots (preferably three) in the shank end of said blank in a third die (by a third blow) and, before ejecting the finished rivet from the fourth die, by extrusion lengthening .the shank and the slots therein while simultaneously further deepening the socket so that it extends into the slotted end of the rivet shank; or in progressive four-blow headers of the two-die type with a pair of dies which progressively pre-form a length of such stock in a first die (by a first blow) into a blank with an upset head having an end socket and with a plurality of longitudinal slots in the blank shank, final-form the upset head while the blank remains in the first die (by a second blow), place the blank thus formed in a second die by a third blow and, before ejecting the finished rivet from said second die, by extrusion lengthening the shank and the slots therein while deepening the mentioned socket so it extends into the slotted end of the rivet shank.

BACKGROUND OF THE INVENTION Progressive four-blow headers are ordinarily provided with a set of four dies, arranged in line, and having means to feed a piece of stock into the first die and then, after each blow of the machine, transferring the workpiece from said first die progressively to the other three, and with a set of four punches respectively aligned with the dies and which perform operations on the workpiece with each blow of the header. When a workpiece in the final die has been acted upon bythe final punch, it is complete and is ejected from the machine. Such headers may be also provided with a set of two dies and four punches operatively associated therewith, the latter being mounted on `two vertically movable slides, each with two vertically spaced punches thereon. The punches of one slide are alternately engaged with one die and the punches of the Y other slide with the other die.

In the four-die header, the four blows are carried out simultaneously; in the two-die header, the four blows are carried out two at a time, alternately.

Heretofore, when rivets required to be slotted, the same, after being formed in progressive headers, were fed to machines which cut or sawed slots therein. This twostage type of operation was, of necessity, costly; the present improvements substantially halve the production time ing the third upset from the second upset.

and materially lower the unit cost. The invention has for its primary object the provision of punch-and-die means, especially for four-blow headers, that not only forms a rivet from a piece of stock, but `also pierces :the same to make it tubular, and forms slots in the end of the shank thereof and which extend and open on the passage in the rivet that is formed by piercing.

This invention also has for its objects to provide such means that are positive in operation, convenient in use, easily installed in a working position and easily disconnected therefrom, economical of manufacture, relatively simple, and of general superiority and serviceability.

The invention also comprises novel details of construction and novel combinations and arrangements of parts, which will more fully appear in the course of the following description, which is based on the accompanying drawings. However, said drawings merely show, and the follo-wing description merely describes, preferred embodiments of the present invention, which are given by way of illustration or example only.

SUMMARY OF THE INVENTION The present forming, piercing and slotting punch-anddie means, in one preferred form thereof, comprises generally a floating first upset or punch 15, a second punch 16, a third punch 17, and a fourth or floating punch 18, all arranged in a single line or bank on the slide 19 of a progressive four-blow header; a first die 20 in operative register with the punch 1S; a second die 21 in register with the second punch 16; a third die 22 in register with the punch 17; and a fourth die 23 in register with the punch 18, all of said dies being iixedly mounted in the frame 24 of a four-blow header. In another preferred form, the punch-and-die means comprises, generally, a set of four punches 25, 26, 27 and 28, the first two mounted on one auxiliary vertical slide 29 and the latter two on a second auxiliary vertical slide 30 of the main slide of the header, a first die 31 alternately operatively engaged by the punches 25 and 26, and a second die 32 alternately operatively engaged by the punches 27 and 28, said dies 31 and 32 being mounted on the machine frame 33 of a twoblow header.

In the drawings, like reference characters designate similar parts inthe several views.

BRIEF DESCRIPTION OF THE DRAWINGS I FIG. 1 is a longitudinal sectional view, at the end of the first blow, of the rst punch and the first die of a fourldie set for forming a first upset from a length of stoc FIG. 2 is a similar view, at the end of the second blow, of the second punch and second die of said die set for forming the second upset from the first upset.

FIG. 3 is a similar view, at the end of the third blow, of the third punch and third die of said die set for form- IFIG. 4 is an enlarged cross-sectional view of the third upset as taken on the line 4 4 of FIG. 3.

FIG. 5 is a view similar to FIG. 3, tand at the end of the fourth and final blow, of the fourth punch and fourth die of the mentioned die set, for final-forming the completed drive rivet from the third upset.

FIG. 6, to the scale of FIG. 3, is a perspective view, in quarter-section, of the completed rivet.

FIG. 7 is a longitudinal sectional View, at the end of the first blow, of the first punch and the first die of a modification comprising a four-punch, two-die set, for forming a first upset from a length of stock.

FIG. i8 is a similar view, at the end of the second blow, of a second punch and said irst die of said punchand-die set, for forming the second upset from the first upset.

FIG. 9 is a similar view, at the end of the third blow, of a third punch and the second die of said set, for forming the third upset from the second upset.

FIG. l is a similar view, at the end of the fourth and final blow, of a fourth punch and said second die, for final-forming the completed drive rivet from the third upset.

DESCRIPTION 0F THE PREFERRED EMBODIMENTS The .first punch is shown as a floating upset case 35 mounted in a bore 34 of the slide 19 and having a bore 36 at its forward end, ,and a counterbore 37 extending rearwardly from the bore 36. A pre-head-forming countersink 38 is provided on the forward end of the bore 36. A helical spring 39, between a lixed abutment 40 and an abutment 41, biases the upset case 35 in a forward direction. An upset pin 42 is slidingly engaged in the bore 36, has end abutment with the abutment 40 when retracted, and is provided `with a reduced forward end 43.

The first die comprises a die case 44 fitted in a bore 45 in header frame 24, a die `46 litted in said case, and a backing block 47 for said case and die. A longitudinal bore 48 extends through said die and block, the forward end of said bore terminating in a countersink 49. A knockout pin 50, extending from a button 51, when retracted has its end 52 defining the bottom of a die cavity 53 which, therefore, is defined by said pin end 52, the bore 48 extending forwardly from said end and the countersink 49.

It will be understood that, with the slide 19 retracted away from the frame 24 so the forward end of the upset case 35 is spaced from the die 20, a cylindrical blank of malleable metal, after being severed from a supply thereof, is entered into the die cavity 53, bottomed on the pin end 52, and is of sufficient length to extend from said cavity toward the forward end of the spring-projected yupset case 35, as limited by the stop pin 54. A shoulder 55 on the upset pin 42 limits the extended position of said pin so the end 43 thereof is suitably spaced from the extending end of the blank.

It will be clear that the extending end of the blank will be upset to the form B to have a bulbous, partlyformed head 56, when the first blow, as in FIG. 1, is completed, the countersinks 38 and 49 combining to forge the blank B, this pre-formed shape and the pin and 43 simultaneously forming a cavity 57 in the end of the head.

The second punch 16 is shown as a punch case 58 fitted in a bore 59` in the slide 19, a backing block 60 for said case, an insert 61 in the forward end of the punch case with a retaining pin 62 therefor, a punch pin 63 in a longitudinal bore of said insert, a support block 64 for said pin, and a backing block 65 for the support block. The forward end of the punch pin 63 has a reduced pilot end 66 that is longer than the end 43 of the punch pin 42.

The second die 21 is similar to the first die 20, the par-ts thereof being designated by the same numerals as those of die 20, but characterized by the letter a.

With the slide 19' separated from the frame 24, the button 51 of the die assembly of FIG. l is moved to cause the lknockout pin 50 to remove the pre-formed rivet B from the die cavity 53. Said rivet is then transferred to the space between the end '66 of the punch pin 63 and the forward end of the die 46a and in register therewith. As the second blow begins, the pin end 66 lirst enters the cavity 57 in said lrivet B. As the blow progresses, the rivet is lirst driven into the die cavity 53a and then, as the punch insert 61 engages the end of the rivet head 56, the latter is forged to its .final shape, as at 67, to the form of the countersink 49a at the completion of the second blow, by the pin end 66. The metal displaced by said pin end and by the insert 61 forms the liat head 67 of the rivet Ba.

The third punch 17 is similar to the second punch 16, the parts thereof being designated by the same numerals as those of punch 16, but characterized by the letter b.

The third die 22 has `a iioating fit in a bore 63 in the frame 24, the same comprising a die case `69 that has a longitudinal bore 70 and is forwardly biased by a spring 71 that exerts its bias from a backing block 72 fit-ted in the ybore v68. A die 73 resides in the bore 70 and has a longitudinal bore 74 that is fitted with a piercing pin 75 held in place by a holder '76 and said backing block 72. As best seen in FIG. 4, the pin 75 is provided with flutes 77 that deline radial fins 78. Three such Iiins are shown, in this instance. A set of knockout pins 79 extends longitudinally through the backing block 72 and through the body of the pin 75 and the liutes 77, the forward ends of said pins 79 terminating short of the forward ends of the tins 78 when the buttons i80 of the knockout pins are in retracted position, as shown. Said pin ends serve to define the bottom of the die cavity 81 which comprises the forward position of the longitudinal bore 74.

With the punch 17 separated from the end of the die case 69, as projected by the spring 71 and limited by the stop pin I83, the knockout pin 50a is projected to cause it to remove the rivet Ba from the die cavity 53a. Said rivet is now transferred to the space between the die case 69 and the end 66b of the punch pin 63b, and in register therewith. As the third blow begins, the pin end `66b enters the cavity 57 in the rivet Ba. As the blow progresses, the rivet is `first driven into the die cavity 81 as the punch insert 61h presses the die case 69 inward against the bias of the spring 71. This force on the rivet causes its rearward end to become impaled on the radial fins 78 of the piercing pin 75, thereby dividing said rivet end into three sector-shaped portions `84, as shown in the cross-sectional view of FIG. 4. At the end of the third blow, the ends of portions 84 are abutted on the ends of the knockout pins 79. The rivet Bb thus for-med has slots y85 that are open due to the thickness of the fins 78 of the piercing pin 75.

The fourth punch 18 is shown as comprising a lioating punch case 86 fitted in a bore 87 in the slide 19, a backing block 88 for said case 86, a iioating punch 89 slidably engaged in a bore 90 of the punch case and having a forward end 91 projecting from said case, a spring 92 biasing said -punch 89 in a forwardly projected direction, and a piercing pin 93 iixedly held in a retainer block 94 closing the rear end of the bore 90 of the punch case 86, said pin extending into a longitudinal bore 95 in the punch 89 and having a reduced end 96 that extends forwardly beyond the end 91 of said punch. A shoulder 97 in the punch case 86 limits the forward projection of the punch 89.

The fourth die 23 comprises a die case 98 fitted in a bore 99 in header frame 24, a die 100 fitted in said case, and a backing block 101 for said case and die. A longitudinal bore 102 extends through said die and block, the forward end of said bore terminating in a counterbore or cavity 103 of the same depth and diametral size as the cavity 81 of the die 73. A countersink 104, similar to that provided in the die cavity 81, is provided on the outer end of said cavity 103. It will be understood that the cavity 103 is of a size and shape to receive the rivet Bb formed by the third blow.

With the punch18 separated from the end of the die 23, the button 80 of the die assembly 22 is moved to cause the knockout pins 79 to remove the rivet Bb from the die cavity of said die assembly. Said rivet is then transferred to the space between the projecting end 96 of the fourth punch 18 and the outer face of the die 23 and in register therewith. As the fourth blow begins, said pin end 96 enters the cavity 57 in the outer end of the rivet Bb. Then, as the fourth blow progresses, said pin end forces the rivet into the bottom of the die cavity 103, and continued progress of this blow causes displacement by said pin end of the metal comprising the Slotted shank of the rivet. Since said shank is confined -by the annular wall of said cavity, and at the bottom by the end of a knockout pin 105 fitted in the bore 102, said metal displacement results in a longitudinally outward extrusion of said shank against the outer end 91 of the floating punch 89. In the process of this extrusion, the slots 85 close to form slits 106, the shank becomes elongated to the form 107, and to a length according to the metal displacement by the pin end 96, and the central hole 108 deepens to overlap said slits 106.

Upon separation of the punch and die of FIG. 5, the button 109 is moved to project the pin 105, causing discharge of the nished rivet R.

The foregoing describes the four-blow operation as carried out by four dies and four associated punches.

The preferred form shown in FIGS. 7 through 10, as hereinlbefore indicated, comprises the set of four punches 25, 26, 27 and 28 and the two dies 31 and 32. The punch 25 is similar to the punch 15 (FIG. 1); the punch 26 is similar to the punch 16 (FIG. 2); the punch 27 differs but slightly from the punch 15, the differences being that the punch case 35e does not oat and the countersink 38 is omitted and the spring 39 is also omitted; and the punch 28 is similar to the punch 18 (FIG. 5). In other respects, the punches 25, 26, 27 and 28 bear the same numerals as the respective punches 15, 16, 17 and 18. The die 31 is similar to the die 22 (FIG. 3), and the die 32 is similar to either of the dies 20, 21 or 23 (FIGS. 1, 2 or 5), the dies 31 and 32 respectively bearing the same numerals as the die 22 and the die 20.

In this four-punch, two-die form of the invention, the initial cylindrical piece of stock is formed by the punch 25 and die 31 of FIG. 7 to the shape of a pre-formed rivet B1 in which the head 110 is formed between the countersink 38 of the punch case 35 of said punch and a countersink 111 at the end of the die cavity 81 of said die, and the shank thereof is pierced by the fins 78 of the piercing pin 75 of said die, the latter in a manner similar to the slotting of the shank of rivet Bb by the piercing pin ofthe die 22.

In this form of the invention, after the punch 25 and die 31 are separated, the rivet B1 remains in its cavity so that, upon shifting of the slide 29 to bring the punch 26 into register with said die 31, the insert 61 and punch pin end `66 will forge the double-chamfered head 110v of said rivet B1 to the at head shape when said punch 25 and die 31 are operatively engaged, as in FIG. 8. Except that the shank remains slotted, the resultant rivet B2 now has a form similar to the rivet Ba of FIG. 2.

After separation of the punch 26 and die 31, the knockout pins 79 of said die are projected to displace the rivet B2 from the cavity of s-aid die, and as before, said rivet is transferred into the space between the punch 27 and die 32 and in register therewith. The punch and die are moved into operative engagement to tightly t the shank of said rivet B2 into the cavity 53 of the die 32. In the process of this introduction of the rivet into the die cavity, the slots 85 may or may not be partly closed, :and the flat head 67 may extend somewhat from the countersink 49 of the die cavity.

With the pre-formed rivet B2 remaining in the die 32 and, after separation therefrom of the punch 27, the slide 30 is shifted to bring the punch 28 into register with the die 32. Now, when the punch 28 is moved into operative engagement with the die 32 and the head end of the rivet B2 therein, the same result is obtained as with the punch 18 and die 23 of FIG. 5; the rivet R, in nal form, is the result, as before.

The die 32, as shown in FIG. 9, embodies a modification of the die cavity 53 in that the same is shown with a chamfer 53', whereas this cavity in FIG. 10 omits this chamfer. The same may be used in cases where it is desired to form the end of the rivet shank with a lead-in taper for easier application. In other respects, the dies 32, as in FIGS. 9 and 10, are alike.

While the foregoing has illustrated and described what is now contemplated to be the best mode of carrying out the invention, the constructions are, of course, subject to modification without departing from the spirit and scope of the invention. Therefore, it is not desired to restrict the invention to the particular forms of construction illustrated and described, but to cover all modification that may fall within the scope of the appended claims.

Having thus described this invention, what is claimed and desired to be secured by letters Patent is:

1. A method for forming a drive rivet from a cylind'rical blank of ductile metal, consisting of:

(a) forming a head on one end of said blank, and a blind longitudinal cavity in said end,

(b) forming a set of sector-shaped portions on the opposite end of the blank by forming a plurality of slots therein to a distance short of the bottom of the mentioned cavity, and

(c) while elongating said opposite end of the blank,

deepening the cavity so the same is partly coextensive and in communication with the mentioned slots.

2. A method according to claim 1, in which the metal displaced when deepening the cavity causes the headed end of the rivet t0 become extruded, accordingly.

3. A method according to claim 2, in which the elongation of the opposite end of the rivet and deepening of the cavity is accomplished during the fourth blow of a fourblow operation.

4. A method according to claim 3, in which the head is formed by the rst two blows, and the plurality of slots are produced during the third blow.

5. A method according to claim 3, in which the first blow pre-forms the head and the cavity therein and the plurality of slots, and the second blow finish-forms the head and extends the depth of the cavity toward but short of the slots.

6. A method according to claim 5, in which the third blow sets the rivet in position to receive the fourth blow.

7. In a four-blow header in which is provided a fixed mounting portion and a mounting portion movable relative to the xed portion,

(a) a set of four punches carried by one of said portions,

(b) a set of at least two dies carried by the other portion,

(c) said punches being operatively associated with said dies to form a drive rivet,

(d) two of said punches and at least one of said dies comprising means to form a head on one end of a cylindrical blank of ductile metal, and a blind longitudinal cavity in said end, while forming a set of sector-shaped portions on the opposite end of the blank by forming a plurality of slots in said end, said cavity and slots being longitudinally spaced,

(e) one of the other punches and the other die comprising means to deepen the cavity to simultaneously extend the same into overlapping communication with the slots, and elongate the rivet.

8. In a four-blow header according to claim 7, the latter punch including a punch pin that forms the deepened cavity and over which the metal of the rivet is extruded as the rivet elongates.

7 8 9. In a. four-blow header according to claim 8, two 3,169,256 2/ 1965 Siebol et al. 10-27 additional dies, one for forming a pre-head on Ithe rivet 3,300,798 1/ 1967 York 10-27 and the other for forming a nished head. FOREIGN PATENTS References Cited 5 1,247,946 10/ 1960 France.

56 UNITED STA?? PATENTS 1 27 CHARLES W. LANHAM, Primary Examiner. gng gllllleu E. M. COMBS, AssstantExaminer. 2,843,928 7/1958 Gandy 10-27 2,843,861 7/1958 Gandy 10-205 10 U-S- C1' X-R- 2,887,694 5/1959 sauter 1o-27 10-27

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