Patent GB-628209-A (GB)
Title: Improvements relating to mechanical presses
IPC: B21D43/11
Filed: 1947-09-17
Abstract: 628,209. Metal-strip feeds. NUFFIELD TOOLS & GAUGES, Ltd., and RICHARDSON, J. A. Sept. 17, 1947, No. 25350. [Class 83 (iv)] Mechanism for automatically feeding thin strip stock to a press comprises a co-operating pair of work-engaging clamps, one carried by a reciprocating slipper and the other by a stationary work-holder adjoining the die, which are controlled by the ram of the press so that, after its feed movement the slipper dwells until the stationary clamp has been closed, the clamp of the slipper is then released and the slipper returns idly to its starting point, whereupon its clamp again engages the work, the slipper dwelling until the stationary clamp has been released and then feeding the next length of stock to the stationary workholder, a device being associated with the slipper for exerting a flattening action on the strip stock during the idle stroke of the slipper. The work-engaging clamp on the slipper 5 comprises a spring-loaded vertically movable pad 12 mounted in a block 13 fixed to the upper member 8 of the slipper and having on its end face vertical and horizontal intersecting slots. A vertical rib 20 on the pad 12 engages in the vertical slot and is interrupted to accommodate a wedge 21 slidable in the horizontal slot. The lower knife-edged end of the rib 20 co-operates with either of notches 23, 24 in the wedge 21 such that when the knife edge engages the deeper notch 23, the pad 12 engages the work 1, and when it engages the notch 24 the work is released. The wedge 21 is moved from one position to the other as appropriate by cams 40, 49 depending from the ram 39, Figs. 3 and 4. The stationary workholder clamp is constructed and operates in a substantially similar fashion. The movable work-holder also includes a spring-loaded roller 52 which bears on the strip and exerts a flattening action. The slipper 5 is fed forwardly by means of a cam 42 on the ram operating through a thrust member 43, eccentric pin 44, lever 45 and link 46, the return stroke being made under the action of a spring 50, Fig. 2. Each workpiece is pierced in a die 4, formed in a die 57 and cropped at 58, being ejected laterally from the die 57 by parallel arms 59 fixed to a member 60 slidable laterally under the action of a linkage 67, 66, operated through a thrust bar 64 by a ratchet pawl 62 on a plunger 63 carried by the ram 39. The return movement of the ejector is effected by the spring 50. The ejected workpieces fall into a receptacle 70 wherein they are stacked by a spring-loaded pad 72 carried on a vertically slidable member 71 urged upwardly by a spring 74 and depressed at the appropriate time in the operating sequence by a pawl carried by a plunger depending from the ram. An ejector mechanism for ejecting a complete pack of workpieces from the receptacle 70 comprises a wheel 82 rotated step-by-step by a ratchet mechanism operated by a cam 87, the ratchetwheel 83 having the same number of teeth as the number of workpieces to be collected in the pack. After each complete revolution of the wheel 82, a pin 91 engages a projection on a lever 93 to move a finger 95 to eject the pack, the finger being returned by a spring 98. A spring-loaded index cam 89 positively locks the ratchet at each step. The wheel 82 may be operated by hand to eject without the press working. The end of the strip 1 is located when a fresh spool is brought into use by a rod 100 which is raised by pressing a spring- loaded rod 99.