US2060690A - Drawing die - Google Patents

Description

Nov. 10, 1936. c. Q R|CHARD 2,060,690

DRAWING DIE Filed July 9, 1934 2 SheetsSheet l 9 /P INVENTOR.

ATTORNEY.

NOV. 10, 1936. c, c; RICHARD 2,060,690

' DRAWING DIE Filed July 9, 1934 2 Sheets-Sheet 2 INVENTOR.

' Cleflmfwi C'Fz'c%ard ATTORNEY.

Patented Nov. 10, 1936 UNITED STATES PATENT OFFIQE DRAWING DIE Application July 9, 1934, Serial No. 734,284

5 Claims.

This invention relates to drawing dies for the forming of sheet metal, the object being to provide a male and a recessed female die part in which the male part is moved along a straight line to fit into the female portion of the die and in which the female portion of the die has a throat or opening at its face less in distance across than the distance across the recess below the opening.

The purpose of such a structure of die is for the formation of a sheet metal part in which the formed metal has a curved portion of more than a half circle as for instance in the formation of an automobile fender. Such fenders at the present time are made generally of at least two parts welded together and the exposed surface at least of the fender at the welded point is, subsequent to welding, finished to provide a uniform smooth surface for application of the enamel or lacquer finish. The object of this invention therefore is to provide a die structure capable of forming a sheet metal article in which some portion thereof is turned to form more than a hemisphere and sometimes termed plus a hemisphere by the trade.

A feature of the invention is involved in the formation of the male portion of the die of two parts, the entering portion of which is pivotally supported whereby in the moving of the male portion into the female portion of the die or Withdrawing the same therefrom, the said pivoted portion may rock on an axis to turn into the recess to beneath the overhang of the female die and of the metal to be formed therein prior to the die parts being in seated relation with the metal and that in the withdrawing movement the die will rock in an opposite direction from beneath the overhand to be drawn from the die on a straight line. In association with such die parts is provided a means for holding the pivoted portion of the male member in position to move in a straight line until it has reached a position to enable the same to be rocked on its pivot with the metal engaging surface thereof in proper relationship with the complemental surface of the female die.

A further object and feature of the invention is involved in the means whereby the pressure in forming an article is not applied to the pivot but is taken by the body of the said pivoted element thus relieving the pivot of the strain incident to formation of the metal part.

These and other objects and various novel features of construction of a drawing die embody my invention are shown in the accompanying drawings in which-- Fig. 1 is a longitudinal vertical section of a drawing die embodying my invention in which the parts are shown in their final relationship in the forming of a sheet of metal.

Fig. 2 is a similar view showing the position of the pivoted male portion of the die prior to its actually entering the female portion die.

Fig. 3 is a section taken on line 3-3 of Fig. 1.

Fig. 4 is a section taken on line l-4 of Fig. 1 showing the form of the die parts in cross section.

Fig. 5 is an elevation of a fender.

The embodiment of the invention shown in the accompanying drawings is a drawing die for the making of automobile fenders in which the curved base portion of the fender indicated at I in Fig. 5 terminates at 2 and the distance between this terminal point 2 and the opposed point 3 of this base portion 1 of the fender is less than the distance across the fender on the dotted line a. The punch in forming the fender must pass into the female die in such position that the length thereof in the plane of the face of the fender the part is approximately equal to the distance between the points 2 and 3 and after entering female die must be turned into the curved part at the forward end of the fender of the form here shown to underlie the point 2 and to practically simultaneously engage the metal throughout its length to properly form the same, the skirt or flanges of the fender 4 being shaped by the die parts as hereinafter mentioned.

This invention therefore seeks to provide a die construction in which the male portion or punch has a pivoted portion of its body so shaped that when turned in one direction it may pass into the female die and thereafter be turned in the opposite direction to engage the portion of the die of greater length. Depending upon the shape of the article being made, the dies will of course be correspondingly shaped for the formation of various articles other than fenders here specifically described in relation to the die parts shown.

The die shown is intended for use in a double acting press customarily employed in fender die work and not here particularly shown. The press, however, has what is known as the blank holder plate 5 attached to the head 6 and to this plate is secured the upper holding ring I. The head and plate 5 and 6 are apertured to receive the driver 8 which is provided at its lower face with an arcuate surface 9 recessed at its center to receive the head of a trunnion l 0. This trunnion has a pin It) at its lower end approximately at the axis of the said arcuate portion 9. The pivoted portion of this punch structure is indicated at and has a triangular recess I2 opening through the arcuate face l3 formed on the same axis as the face 9 of the driver.

The pin Ill extends into apertures indicated by dotted lines M in the body of the pivoted element II to provide lost motion of the pin H in the aperture I4. Thus as the punch member including this pivoted head I is moved into the die part Hi to engagement with the metal, as is the position of the parts in Fig. 1, the surface l3 is contacted by the concentric surface 9 of the driver and the pressure in formation of the fender part is taken between these surfaces and not on the pin ID. The upper die part is dual in character, it having the male punch element formed of the parts 8 and H and the upper ring member 1 which has an opening l5 of the same length or diameter of the opening in the face of the lower ring or female die part l6 which is supported on a base |6*-. In operation the upper ring 1 is first moved downwardly to engage the metal I! prior to movement of the pivoted punch element I I by the arm 8 into the female die. The upper ring I may be provided with a bead l8 to fit a complemental groove in the face of the female element I6 whereby as the upper ring I is moved to the position shown in Fig. 2, the sheet metal blank I! is clamped at its opposite ends to hold the sheet during the drawing operation. The relationship of the die parts is such that when the punch is withdrawn, the face portion of the pivoted die part II lies in the opening l5 of the upper ring 1 and as the wall of this opening is of sufficient length that, in its movement in respect to the pivoted punch part I the heel IQ of the die part II lies against this wall of the aperture l5 and the portion H, as shown in Fig. 2, is swung to the right of the position of the part shown in Fig. 1.

The die part II however is not free to swing on the pivot pin but is actuated and held in its pivotal movement by cams 20 and 2| as shown in the section Fig. 3 and a similar pair of cams, one of which is indicated at 22 in Fig. 2 on the opposite side of the die part II to which these cam elements are secured as by means of bolts 23. These cams extend upwardly from the female die part I6 through apertures provided in the base of the upper ring I to the interior of the ring which is formed with a recess 24 into which they extend on opposite sides of the driver element 8 of the punch. The members of each pair of cams, as 20 and 2| of Fig. 3, are on opposite sides of the driver element 8 and in opposed relation with the other pair of cams one of which is indicated at 22 in Fig. l. The cams 20 and 2| as shown in Fig. 1 have cam faces 25 and the cam members 22 have oppositely inclined faces 26 as shown in Fig. 1 and in both cases the pairs of cams on one side of the driver at the left side of Fig. 1 have inclined faces oppositely disposed in practically parallel relation with the inclined faces 26 of the cams on the right side of Fig. 1. Between the cam 28 and 22 and 2| and its opposed companion member 22 extend the actuating bars 21 and 28 as will be understood from Fig. 3 and the upper ring also has a pair of brackets 29 on each side for the purpose of strengthening the side walls of the upper ring. The driver 8 has an elongated part 30 on one side and 3| on the other side as shown in Fig. 3 which are formed with a way to receive these actuating bars and the ends 0 0h? bars are rounded as shown in Fig. 1 and respectively engage the cam faces 25 and 26.

A plate 32 is provided on the side of the members 3B and 3| to hold each bar in its way in which it is slidable. Each bar also has a pin 33 approximately centrally disposed between the ends thereof, as indicated more clearly in Fig. 4, which extends into vertically elongated apertures 34 in the pivoted punch element H on opposite sides of the recess l2 therein. The driver 8 is attached to the punch press by means of an interposed element 35 and by which the driver 8 is moved vertically in the position of the parts shown. As the punch moves from the position shown in Fig. 2 to the position shown in Fig. l, the actuating bars 21 and 28 engage the respective cam faces and move the bars from the position shown in Fig. 1 and thus rocks the punch element II on its pivot. The cams and the bars are so positioned that, as the punch element moves from the position shown in Fig. 2 it is moved in a straight line into the opening of the female die portion l6 and as the heel portion IS of the punch element passes out of the upper ring 1 the ends of the actuating bars engage the cams and rock the member II on its pivot H] to the left of the position shown in Fig. 2. As this movement proceeds the punch element II is turned to the position shown in Fig. 1 just prior to the actual formation of the article and as this punch element comes to the position stated the arcuate surface I3 is in engagement with the arcuate portion 9 of the driver 8 so that the final forming pressure is taken on the end of the member H and not on the pin due to the lost motion heretofore mentioned of the pin H) in its aperture in the part Thus the final metal forming movement of the punch part is in a vertical line and the metal is engaged to an equal degree throughout its surface between the die faces whereby the drawing of the metal is uniform.

A stop element 36 is provided in the recess of the member H to limit the turning thereof on the pivot Ill to too great a degree, it being desired to hold the heel IQ of the member II in contact with the wall of the aperture |5 in the upper ring 8 to thereby properly enter the female die l6.

Upon upward movement of the driver in withdrawal of the member H from the female die portion l6 there is a straight line movement of the driver to which the bars 2'! and 28 are slidably secured and due to the ends of the bars engaging the inclined surface 25 of the cam elements 20 and 2| on one side the bars are moved to the right of the position shown in Fig. 1 practically to the position shown in Fig. 2 which turns the member H on its pivot Ill permitting it to be withdrawn from the overlying portion of the female die to within the recess defined by the wall of the apertures IS in the upper ring I. Thereafter the upper ring 1 is moved upwardly to permit removal of the formed part and introduction of a new part whereupon the forming movement of the parts as above described is repeated. The face of the element in cross section and likewise the female die is shown in Fig. 4 being of the form for the making of a fender with its side flanges but, as previously stated, the die while here shown as of a form for making a fender may be of a shape to form any desired part. This form of die is of great value where the formed part has a portion thereof so overlying the body as to make it difiicult or impossible to introduce a solid punch or one piece directly into the female die portion. In my invention the punch in most instances is supported on a pivot extending at a right angle to the plane of the portion having the overlying or recurved part.

From the foregoing description, it will be evident that the described invention is adaptable for use in the making of sheet metal parts Wherein the article formed has one portion overlying another portion to such extent that it is impracticable to move a solid punch into a female die part for the forming operation; that by the construction described, I have provided a drawing die in which the two die parts have a relative straight line movement in the forming and withdrawing movements of the male portion of the punch and yet that may be turned to position to properly form an overlying part simultaneously with the formation of the body or remaining portion of the article being formed without submitting any part of the metal to sliding contact with a die part, and that the various objects and features of the invention are secured by the construction described, it being understood, however, that various changes in the form of the various parts may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

Having thus briefly described my invention, what I claim and desire to secure by Letters Patent of the United States isl. A drawing die, comprising male and female die parts, the said female die having a recess undercut on one side and the male die having a complemental projection on one side, a holding means for supporting a piece of metal relative to the female die for the shaping operation, said holding means having an aperture therethrough aligned with the male die part and through which the said die part is movable into the female die, said ma e die part being formed of two members, one movable in a fixed line and the other a terminal die part pivoted to the first named part, the said holding means being movable to engage the metal to be formed prior to movement of the male die part into the female die part, the said first named part of the male die and the pivoted portion having concentric surfaces, the pivotal support being formed with sufficient lost motion as to permit the concentric surfaces to come into pressure contact in the formation of the article to relieve the pivot point of strain, and means automatically operating to turn the said pivoted part of the male die as it enters the female portion of the die to position the projection in the undercut portion of the female die as the die faces approach para lel relation, the said automatic means further auto matically operating to turn the said pivoted portion of the male die part in the opposite direction as the male die is withdrawn after completion of the forming operation.

2. In a drawing die, a stationary female die and a movable male die, said male die having a terminal end portion of a shape complemental to the shape of the recess of the female die and a reciprocable portion to which the terminal portion is pivoted, the female die part having a recess of greater distance fro-m side to side below the surface than at the surface providing an overhang and the pivoted member having a projecting portion to be moved thereinto in the forming of a sheet of metal, stationary cam members on opposite sides of the female die element, a sliding bar on the reciprocable portion of the male die element, the respective ends of which engage the opposed cam elements, said bar having a pivotal connection with the pivoted die and said cams of such form that in movement of the male die toward the female die, the cams turn the pivoted die part as it enters the female die to position the said forming surface of the die in substantially parallel relation with the female die and on movement in the opposite direction the cams operate the bar to turn the pivoted die element in an opposite direction to withdraw the same from the female die.

3. In a drawing die for the purpose described, a female die having a recess opening through its face and a male die portion having a pivoted part of a shape corresponding to the female die recess and movable thereinto, a pair of stationary cams positioned at opposite sides of the female die and extending upwardly therefrom, a bar slidably supported by the male die, the ends thereof engaging the respective cams providing a means for turning the pivoted portion of the male die in one direction on the forming stroke and in the opposite direction on the Withdrawing movement, and a holding ring movable in timed relation with the movement of the male die for engaging and holding a sheet of metal over the recess of the female die prior to engagement of the pivoted die member therewith.

4. In a drawing die, a female die part having a recess undercutting the face of the die providing an inturned flange on one side, a male die part comprising a reciprocable element and a pivoted part provided with a projection on one side to engage the said undercut portion of the female die and of a shape otherwise complemental to the female die, said pivoted part having a curved surface whose axis coincides with the axis of the pivoted part and the other part of the male die portion having a concentric curved surface, the pivotal connection being of a construction to provide sufficient for lost motion to permit the concentric surfaces to come to engagement in the forming of the article, and means for automatically causing said pivoted part of the male die to turn as it enters the recess of the female die to engage said undercut portion and to automatically turn in an opposite direction on withdrawal.

5. In a drawing die, a female die part and a male die part, the female die part having a recess undercutting the face of the die providing an inturned flange on one side and the male die comprising a reciprocable element and a pivoted part provided with a projection on one side to engage the said undercut portion and of shape otherwise complemental to the female die recess, and a stationary cam means for causing the pivoted portion of the male die to turn as it enters the recess of the female die to engage in the undercut portion and to turn in an opposite direction on withdrawal.

CLEMENT C. RICHARD.

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