Patent GB-580602-A (GB)
Title: Improvements in or relating to punch presses
IPC: B21D45/00
Filed: 1944-02-21
Abstract: 580,602. Punching. STEVENS, A. H. (Dayton Rogers Manufacturing Co.). Feb. 21, 1944, No. 3199. [Class 83 (iv)] A punch press comprises a punch mounted on a punch holder supported on a bolster plate, a die plate supported in operative relation to the punch and having means for guiding strip material to be punched between the punch and the die plate, and a number of stripper pins selectively supported in the punch holder plate. The press comprises two side members 2, Fig. 1, connected by upper and lower crossmembers 4, 5 and adjustably mounted on a base 9 by means of a pivot 11 and a pin-andslot connection 12, 13. A crapk-shaft 19 mounted in the upper frame may be driven from a fly-wheel 16 through a one-revolution clutch (not shown) to reciprocate a ram 21 through a pitman 23. Brake mechanism 18 (not shown) prevents overrunning when the clutch is disconnected. The lower crossmember 5 supports a bolster plate 26 with a central opening for a filler block 28 supported by the top of the movable frame 31 of a die cushion comprising a resilient element 33 clamped between a counterbore 32 in the frame 31 and a washer 34 by means of a nut 36 in threaded engagement with a sleeve 35. A nut 37 on the upper end of the sleeve bears on an upstanding hub of the frame 31 and the whole assembly is suspended from a bar 39, bolted to the member 5, by means of a tubular member 42 passing through the sleeve 35 to engage an adjusting wheel 44 on which bears the lower end of the sleeve. A punch holding plate 45 is secured to the bolster plate by clamping elements 46 with projections 58 which limit the upper movement of a die plate 57 attached by rivets to a lower plate or nest 56, Fig. 6, having a guiding passageway 61 for the work strip 62 and an opening 63 in alignment with the die opening 59 and constantly engaged over the punch 51 so as to form a guide for the die. The punch is secured to the plate 45 by bolts 52 and around the periphery of the punch are stripper pins 55 which rest on the block 28 and pass through holes in the plate 45 to support resiliently the plate 56 and die 57. The plate 45 is formed with a number of bolt holes and stripper pin holes to suit various sizes and shapes of punches and dies. The strip material 62 is correctly positioned for a punching operation by means of a detent 79 of a stop finger 65 which engages the rear wall 80 of the space left by the removal of the last blank. At its rear end, the member 65 has two slots by which it is mounted on a block 67 by means of studs 81, 82 so as to be capable of limited longitudinal movement and also a rocking movement as shown in Fig. 8. The block 67 is adjustably clamped to a member 68 extending .rearwardly from the plate 45. On the down stroke of the ram 21, the die plate 57 is pressed over the punch to sever the blank 90, as shown in Fig. 8, and at the same time the edge of the plate 56 engages an offset portion 78 of the finger 65 to disengage the detent 79 from the wall 80 of the strip whereupon the detent moves forwardly under the strip due to the action of the spring 84 which on the upward movement of the plate 56 urges the detent upwardly to engage the next wall of the strip. A lever 88 is provided for manual operation of the finger 65 if necessary. On the upward movement of the ram 21, a projection 116 on the pitman engages, a roller 115 to actuate a lever 109 mounted on the cross-member 4 and connected through links 104, 99 to a lever 93 which is in turn actuated to move upwardly a knock-out pin 91 which ejects the blank from the die plate and moves it upwardly for some distance in contact with the ram. The pin 91 then descends under the action of a spring 98 and a cam on the crank-shaft 19 operates a valve to supply pressure air to a nozzle 119 by which means the blank is blown into a receiving tray 120.