Patent GB-708509-A (GB)
Title: Step-by-step feeding mechanism for elongated elements
IPC: B21D43/11
Filed: 1952-10-31
Abstract: 708,509. Metal strip feeds. DICKERMAN, H. E. Oct. 31, 1952, No. 27374/52. Class 83 (4) A reciprocating gripper feed for metal strip or sheet has friction clutch means associated with first and second gripping means whereby the forward movement of the first tends to increase its grip and to release the grip of the second, and return movement of the first tends to release its grip and to increase the grip of the second. In an embodiment a stationary support 2 secured to the press has a forward slide part 4 on which reciprocates a slide 6. A wall 12 on the slide 6 carries a roller 14 on a stud 16 and the support 2 has a wall 18 provided with a bore 20 for receiving a rod 22 one end of which is adjustably fixed to the wall 20 the other end extending through an opening 26 in the wall 12 and carries a piston 28 working in a bore 30 in said wall. A compression spring 32 surrounds the rod 22 and the stroke of the slide and length of strip sections to be fed may be varied by adjusting the rod 22. The strip being fed is supported by front and rear anvils 52 and 54 respectively. Studs 36 and 38 projecting from the walls 12 and 18 respectively carry oscillatable pressure levers 40 and 42 respectively. The levers 40 and 42 have notches 68 and 70 respectively for receiving the upper ends of plates 72 and 74 provided with lower and upper openings 69 and 71, Fig. 5, and having hardened inserts at their lower end for bearing on the strip being fed. Forward and rear elongated members 58 and 60 have their inner adjacent ends frictionally associated by friction clutch means 62. The forward end of member 58 has a reduced portion for extending through the lower opening 69 of the plate 72 and an anchor 78 for a spring 76 attached to the lever 40. Similarly the rear end of member 60 has a reduced portion and an anchor 82 for a spring 80. The friction clutch means 62 comprises spaced vertical side extensions 84 and 86 on the member 58 and friction plates 88 and 90 the plate 90 being interposed between the members 58 and 60. A spring 92 overlies the plate 88 and is held in position by a transverse retainer 94. The side 86 of member 58 has a portion 87 for manually elevating the levers for permitting shifting, insertion or withdrawal of the strip from between the gripping members. Ears 112 and 114 on the members 58 and 60 engage notches 108 and 110 in the levers 40 and 42 respectively. Bosses 96 and 98 extending from the walls 12 and 18 of the slide support spring-loaded adjusting screws 100 and 102 which extend through the upper walls of the levers 40 and 42 respectively. The screws limit counter clockwise movements of the levers 40 and 42. In operation a cam 120 attached to the movable member of the press moves the slide rearwardly, i.e. in the non- feeding direction against the spring 32. Strip material is passed over the anvils 52 and 54 and the lower ends of plates 72 and 74 are disposed on the strip and the spring-loaded levers 40 and 42 act on the plates. As the slide moves rearwardly the member 58 through the clutch mechanism urges the member 60 rearwardly to cause the plate 74 to firmly clamp the strip on to the anvil 54 and prevent rearward movement of the strip. When the slide is moved forwardly in the feeding direction by the spring 32 the strip is wedged between plate 72 and anvil 52 and a portion of the strip depending upon the adjustment of the rod 22 is fed forwardly. At the same time the member 60 through clutch 62 is urged forwardly by member 58 and the strip is released from the grip of plate 74 and anvil 54. After each or during each downward movement of the press head the strip is released to relieve any stresses and strains in the strip. This is accomplished by providing a forward offset 126 on the vertical face of the cam 120 so that as the roller 14 engages the offset during downward movement of the press head the spring 32 kicks the slide forwardly a few thousands of an inch whereupon the member 60 moves forward and releases the grip of plate 74. On the upward movement of the cam the slide is returned when the roller leaves the offset and plate 72 releases the strip.