Patent GB-493367-A (GB)
Title: Improvements in or relating to methods of and apparatus for embossing
IPC: B41M1/24
Filed: 1937-04-06
Abstract: 493,367. Embossing; making dies.' KAUFFMAN, M. April 6, 1937, Nos. 9759 and 9760. Convention dates, April 6, 1936 and Aug. 13, 1936. [Classes 83 (ii) and 83 (iv)] In a method of and apparatus for embossing a metal plate or like, contiguous small portions of metal are displaced progressively to produce a flow from one side of the neutral axis to the other to produce a raised rib on one side and a corresponding depression on the other side of the plate. The invention may be applied to the production of relief dies for stamping, embossing, printing, or marking metal, leather or other materials, or for making other dies. The method is particularly suitable for embossing lead, zinc, brass, aluminium, copper and certain steels. A power driven eccentric 2 reciprocates a cross-head 3 in guides of the frame 5. A swivel screw 6 connects the cross-head to a ram 7 movable in bushing 9 of a guide 8. The male die 10 is secured in the plunger by a collet 11. The matrix or female die portion is adjustably mounted on the table 13 and a stripper 14 may be spaced above the matrix in accordance with the thickness of the work to be operated on. In the position of the parts shown in Fig. 1, the cross-head may reciprocate without operating the plunger 7, but by depressing a member 16 the screw 6 is lowered by the member 19 so that a lock member 15 may be forced by its spring into a position between the head of the screw 6 and the plunger to cause the latter to reciprocate with the crosshead. The plunger and the male die may be rotatably adjusted about a vertical axis by first withdrawing a locking plunger 23. The matrix portion 12 may be a U-shape as shown in Fig. 2, the recess 26 being thus closed at one end by the part 27 of the U. In a modification, Fig. 4, the recess 261 may be formed by two spaced lugs 25<1> having inclined sides. As the work is progressively fed over the matrix, each downward stroke brings the die 10 down on to the upper face of the work and shears off small portions of the material which are forced downwards into the recess 26 to produce a rib 29 on the lower surface of the work-plate and a corresponding channel 30 on the upper surface. The sides of the relief pattern are limited by the spaced lugs 25 or 25<1>. The pressure of the male die causes the detached shavings to become bonded with the previously cut material. The rib 29 is thus progressively produced by the feed of the plate 28 and the direction of the feed may be varied to produce irregular designs either continuous or non- continuous, of the forms shown in Fig. 15. If the male die is of substantially the same width as the recess of the matrix, the stroke of the male die does not extend to the lower surface of the work to avoid complete severance of the plate, but if a narrower die is used, the tool stroke may extend below the lower work surface, as shown in Fig. 18. In other cases, the stroke of the die is such that the displaced metal does not completely fill the recess 26 so that the bottom of the relief is more or less rounded transversely. For very narrow relief patterns, the taper-sided matrix shown in Fig. 4 is preferably employed. One form of male die is shown in Fig. 23. The shoulder 10b cuts off a small portion at each downward stroke, while the bottom face 10c displaces portions 28<1> of the plate and causes it to be flowed into the recess 26. In Fig. 23, the tool is in its raised position and may serve as a stop to prevent overfeeding of the work in the direction of the arrow. Complementary male and female dies may be made by using an embossed plate as a mould pattern. In a modification, Fig. 7, the male die may have a substantially flat front face. In this form, the die must be raised above the level of the plate to permit the feed. Other forms of male die are also described. Another modification, Fig. 20, has the ends 40 of the lugs 25<11> inclined to the recess 26<11>, so that a junction may be made between one relief and another. In another modification, Fig. 13, a filler plate 35 is placed over the work-plate 28 and the male die completely severs a part 36 from the filler plate and forces it into the channel of the workplate thus leaving the embossed plate with a substantially flat upper surface and strengthening the work.