US3471879A - Rivet-forming dies - Google Patents

Description

Oct. 14, 1969 R. F. KOLEC RIVET-FORMING DIES 3 Sheets-Sheet 1 Filed Feb. 20. 1967 N m m mm 4 f r J J J WWW f 3 Sheets-Sheet 5 Oct. 14, 1969 R. F. KOLEC RIVET-FORMING DIES Filed Feb. 20. 1967 wafer K01 BY linited States Patent 3,471,879 RI v'ET-FGM'HNG BEES Robert F. Kolec, Whittier, (Zalif, assignor to Glympic Screw 8: Rivet Corporation, Downey, Calif, a corporation of Daiifornia I iled Feb. 20, 1967, Ser. No. 617,205 Int. Cl. 1321i; 1/58 US. Cl. Ill- 2 Claims AESTRACT [BF THE DKSCLQSURE Die means for forming tubular rivets from short lengths of wire stock in a double-blow, cold header, the die means comprising an extrusion die combined with a knock-out mechanism for discharging the finish-formed rivet from the header, and a slide-mounted holder for a first-blow extrusion punch and a second-blow rivet-finishing member.

Background of the invention Tubular rivets have been produced from slugs or rods of malleable metal, as aluminum or alloys thereof. Such items should be manufactured at a high rate of production, with long-lasting tools or dies, and at low cost, in order to be competitive. Cold headers, particularly those of double blow or double stroke are useful machines for heading rivets at high rates of production and low cost. This invention contemplates providing such cold headers with novel, improved, and long-lasting extrusion-forming dies to produce tubular rivets at high rate of production and low cost, commensurate to the rate and cost of heading solid rivets.

Summary of the invention A generally conventional double-blow, cold header is provided with a wire feed 10, cut-off 11 and means 12 to transfer the length of stock 13 that is cut from a supply of wire to a position from which it is fed to a forging die; power-operated toggle means 14, mounting a punch slide 15, and provided with a holder 16 for two punches that are in vertical alignment; shifter means 17 for vertically shifting said slide 15 so the two punches carried thereby are alternately aligned with the forging die to, thereby, perform two successive forging operations on a piece of stock 13 positioned in the die; a compensator 18 to control travel of the shifter means 17 to insure that the slide 15 is moved accurately so that the two punches thereon are positioned, alternately, in true register with the die; and means 19 to dislodge a forged work piece from the die to make room for a new length of stock 13. The abovegenerally-described means receive their power from a crankshaft 20 that may be pulley-driven, the same mounting suitable cams set in relation to the throw of the crankshaft to synchronize the operative movements of said means.

According to the invention, the present rivet-forming means comprises, generally, a die case for receiving a length of stock 13 and fixedly disposed in a die block 26, stripper means 27 operatively associated with the means 19, means 28 coaxial with the stripper means comprising a pin over which the rivet is extruded and to remove a portion forming a bridge across the bore of the rivet when so extruded; means 29 controlled by the compensator 18 to move the means 28 in a direction to remove or shear said bridge; an extruding tool 30 carried by the holder 16 of the slide 15 and which is in axial register with the die case 25 in one position of said slide; and a rivet-finishing member 31 carried by said holder 16 below the tool 38 and which is in axial register with the die case in the other position of the slide 15, said tool 30 and member 31 replacing the forging tools ordinarily mounted in the holder and successively performing the two blows employed to form the rivet which is dislodged from the die case by the stripper means 27.

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 and which is based on the accompanying drawings. However, said drawings merely show, and the following description merely describes one embodiment of the present invention, which is given by way of illustration or example only.

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

FIG. 1 is a broken plan view of a double-blow, cold header provided with the present rivet-forming means.

FIG. 2 is a partial elevational and partial sectional view, the same being taken on the line 22 of FIG. 1.

FIG. 3 is an enlarged vertical sectional view of a portion of the punch slide and showing the extruding punch and rivet-finishing member of said forming means.

FIG. 4 is a further enlarged and broken longitudinal sectional view of die case, stripper means and extrusion core means of the rivet-forming means, the same being shown preparatory to receiving a length of stock.

FIG. 5 is a further enlarged longitudinal sectional view of the right portion of FIG. 1 and the cooperating portion of the extruding tool at the beginning of the first blow.

FIG. 6 is a similar view at the completion of the first blow and forming a rivet from the length of wire stock that is blind due to a bridge formed across the head end of the rivet.

FIG. 7 is a similar view at the end of the second blow and removal of said bridge to provide the rivet with through hole or passage.

DESCRIPTION OF THE PREFERRED EMBODIMENT The conventional means 10 to 20, above generally described, are mounted on a machine base 35 having an opening 36 in which the toggle means 14 is disposed, a front end 37 of said base 35 being recessed for the die block 26 and having a clearance bore 38 through which the stripper means 27 extends, a side wall 39 of said base mounting the compensator 18, and said wall 39 and the opposite wall 4t) mounting the bearings (not shown) for the crankshaft 20. The wire feed means 10 is shown as a pair of circumferentially grooved feed rolls that are intermittently advanced by conventional feed means driven from the shaft 20, the wire cutoff 11, and the transfer means 12 for moving a cut length of wire 13 into register with the axis of the die case 25. The shifter means 25 to vertically reciprocate the punch slide 15 is operated by a rockshaft 41 which has an arm 41:: connected to the compensator 13, a cam (represented by the groove 42) on the shaft 20, imparting operative movement of the compensator to cause overtravel of the slide 15 were it not for the springs 43 which take up the extra motion at the extremities of the stroke, thereby insuring that the axes of the members 30 and 31 achieve alternate, accurate aligmnent with the axis of the die case 25. This conventional reciprocative movement of the compensator arm 44, causes a similar movement of a bracket 45 affixed to said arm. The means 19 is also operated by a cam on the shaft 20, in a conventional manner, to cause the slide bar 46 to move in the bracket 47 in a direction to bear against the end 48 of a knockout lever 49 on a pivot 50 to cause the oppo- 3 site end 51 of said lever to push on the end 52 of the stripper means 27.

The die case 25 (FIG. 4) is disposed in a bore 55 of the die block 26, the same comprising a sleeve 56 slidingly fitted in said bore, a die 57 fitted into said sleeve and having a concentric bore 58 extending longitudinally therethrough, said die, by means of a set screw 58a, limiting the projected position of the sleeve, a fitting 59 telescopically engaged in a counterbore 60 in the sleeve 56, a helical spring 61 in said counterbore with one end engaged with a shoulder 62 of the die and the opposite end with said fitting 59, said spring biasing the fitting against a limiting face 63 of the end 37 of the machine base 35. In this die structure, the bore 58 defines the die surface that dorms the outer diametral size of the rivet 64 (FIGS. 6 and 7) that is extruded by the present means.

The stripper means 27 comprises a stripper sleeve 65 that is fitted in the bore 58 with its length coextensive with the length of said bore, a flange 66 on the inner end of said sleeve, a plurality of longitudinal rods 67 extending from said flange 66, a tube 68 connected to and extending through the bore 38 in the base end 37, and the mentioned end 52 on said tube and shown in the form of a flange beyond the front face of said base end 37.

The means 28 is shown as a rod 69 slidable in the bore of the tube 68, an end piece 70 adjustably carried by the outer end of the rod 69, a bore-forming rod 71 extending from the inner end of said rod into the bore of the sleeve 65, and a head 72 on the inner end of the rod 71 and having a snug, sliding fit in said sleeve bore. As shown in FIGS. 4 and 5, said rod head 72 is spaced from the inner face 7 3 of the die 57 which, at the beginning of a rivet-forming extrusion, is flush with the inner face 74 of the sleeve 56.

The means 29 is shown as a cam 75 that is held in operative engagement with the end piece 70 of the core means 28 by a bracket 76 that extends from the end 37 of the machine base, said cam 75 having two ofiset faces 77 and 78, a hydraulic cylinder 79 carried by said bracket and having a piston, the stem 80 of which is connected to and moves the cam 75 in one direction or the other depending on hydraulic pressure being admitted into cylinder 79 through conduit 81 or 82 connected to the opposite ends of said cylinder, as in FIG. 1. FIG. 2 shows said conduits 81 and '82 connected to the opposite ends of a second hydraulic cylinder 83 that is mounted on a bracket 83a on the base wall 39. The piston of said cylinder has a stem 84 that extends through the bracket 45 and carries two adjustable abutments 85 and 86 on opposite sides of the bracket 45. Hydraulic connections 87 are provided at the opposite ends of the cylinder '83. It will be understood that, in one camshifted position of the compensator 18, the bracket 45 will shift the stem 84 and the piston thereon to open line 81 to hydraulic pressure, and that in the other camshafted position of the compensator, said bracket will open the line 82.

The extruding tool 30 comprises a punch body 88 in which is housed a sliding ram 89 that has a rearwardly extending end 90 that is adapted to engage the wall 91 of the holder 16 when retracted, and a forwardly extending punch pin 92 that extends through a bore 93 in the body 88. A head-forming cavity 94 is provided in the end of said body, around the punch pin 92. A spring 95 biases the ram and the punch pin 92 thereon in an outward direction.

The rivet-finishing member 31 comprises a body 96 with a cavity 97 similar to the cavity 94, a passage 98, the same diametral size as the head 72 of the bore-forming rod 71, extending rearwardly from the cavity 97, an inner flared extension 99 of the passage 98, an enlarged bore 100 extending rearwardly from said flared extension, and a discharge opening 101 in said bore 100.

Operation After the means 10 has fed the wire and the means 11 has cut a length 13 thereof and the means 12 has transterred said wire length 13 into alignment with the die axis, as shown in FIG. 5, the toggle means 14 is straightened by the crankshaft 20 to move the extruding tool 30 in a direction toward the die case 25. The punch pin 92, being in axial alignment with the wire piece 13, the latter will be moved into the bore 58 of the die 57. The spring 61 will maintain said die in the projected position of FIG. 4, while the pin 92 pushes the wire piece 13 against the end of the stripper sleeve 65 which retracts and, in so doing, causes retraction of the stripper means 27 and of the lever 49 from the position of FIGS. 1 and 4.

When the wire piece 13 encounters the head 72, which is held immobile by the face 77 of the cam 75, the ductile metal thereof will flow around said head, filling the bore 58 as the extrusion progresses. As the body of the tool 30 continues its movement toward the die, the resistance on the end of the pin 92 increases, causing the same to be retracted against the bias of the spring 95. Such retraction will cause the ram end to engage the wall 91, the same occurring as the swaging end of the pin 92 is retracted back to the bottom of the cavity. When the forward end of the tool body 88 encounters the face 73 of the die 72, it will cause the die and its case sleeve 74 to be moved until its movement is arrested by the fitting 59. At this time, the position of the parts is as in FIG. 6, i.e., the end of the first blow, is reached. The rivet shank 102 is formed around the rod 71 and its head 72, the rivet head 103 is formed in the cavity 94, and a shallow depression 104 is formed on the outside of the head 103 by the swaging end 105 of the punch pin 92.

The toggle means 14 is now contracted as the shaft 20 turns, causing the slide 15 and the tool 30 to retract 'away from the die and when so retracted, the shifter means 17 causes an upward movement of the die holder to place the rivet-fin-ishing member 31 in register with the die axis, thereby replacing the tool 30. The spring 61 will be free to expand and return the die case to the projected position of FIGS. 4 and 5 but with the pre-formed rivet placed Where the same was formed.

As the shift of the slide 15 terminates, the crankshaft 20 again straightens the toggle means 14 moving the member 31 toward the die. The body 96 of said member, acting in the same Way as the body 88 of the tool 30, encounters the die 57 and, with-the rivet head 103 in the cavity 97 of said body 96, again moves the die 'and the preformed rivet against the bias of spring 61 to its inwardly retracted position. At this time, the means 29 is actuated by the bracket 45 of the compensator to shift the cam 75 and bring the high, offset face 78 thereof into engagement with the end piece 70 of the rod 71. This movement of the rod will shift the head 72 thereof in a direction toward the rivet head 103 to shear the bridge 106 at the middle of the head. FIG. 7 shows the rod 71 so shifted and the bridge 106 severed and displaced from its initial location. Upon completion of this shifting movement, the bridge 106 will be be clear of the rivet head 103 and disposed in the passage 98 of the member 31. Any previously sheared bridge in said passage will be displaced into the flared extension 99 and ultimately fall from the discharge opening 101. This is the end of the second blow and the rivet is now completely formed.

Finally, the means 19 is operated by the crankshaft 20, causing the bar 46 to press on the end 48 of the lever 49. As a result, said lever will move so its end 51 will engage the stripper means 27 to dislodge the rivet from the die passage 58. Now, the means 46 is operated to release the lever 49 so that, upon the next extrusion of a rivet, the stripper sleeve 68 may retract from the position of FIGS. 4 and 5 to that of FIG. 6, during the extrusion process.

Upon return of the slide 15 to its high position, the above cycle of operation may be repeated.

While the foregoing has illustrated and described what is now contemplated to be the 'best mode of carrying out the invention, the construction is, 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 form of construction illustrated and described, but to cover all modifications 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. In a double-blow cold header having an axially hollow die and provided with a rivet-extruding tool which, when axially aligned and engaged with said die, produces a pre-formed rivet having a tubular shank and a solid head on said shank closing the hollow of the shank, and with a rivet-finishing tool which, when axially aligned and engaged with the die, extends the length of said hollow in the shank of the preformed rivet and through the head thereof,

(a) means including a rod with a head thereon extending into the hollow of the die and outwardly therefrom in a direction away from the extruding and finishing tools,

(b) said extruding tool being provided with a punch to force a length of malleable wire stock, end first, into the die passage and into engagement with the head on the mentioned rod to cause extrusion of the wire stock around the headed end of the rod to form the mentioned tubular shank of the pre-formed rivet,

(c) means to project the mentioned rod, when the rivet-finishing tool is axially aligned with the die, thereby to project the head of said rod beyond the end of the hollow in the rivet shank and shear off axial portions of the rivet head, extending the hollow, as mentioned,

(d) the rod-projecting means comprising 'a cam provided with two offset cam portions, one of which is engaged with the outwardly extending end of the rod to hold the same in extrusion position, and

(e) means to shift said cam to bring the other cam portion into engagement with said outwardly extending end of the rod to project the same from the mentioned extrusion position to the hollow-extending position.

2. In a double-blow cold header as defined in claim 1 and in which the header is provided with means to move the rivet-extruding rand rivet-finishing tools to their mentioned axial alignment with the die, alternately, means controlled by the latter means to shift the rod-projecting means to bring the first-mentioned eam portion into engagement with the rod when the extruding tool is aligned with the die and to bring the other 0am portion into engagement with the rod when the finishing tool is so aligned.

References Cited UNITED STATES PATENTS 1,900,572 3/1933 Lyman 1024 2,586,336 2/1952 Huck 1027 2,715,232 8/1955 Egan 1024 CHARLES W. LANHAM, Primary Examiner LOWELL A. LARSON, Assistant Examiner US. 01. xn, H4

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