Patent GB-602308-A (GB)
Title: Improvements in or relating to punch presses
IPC: B21D28/04
Filed: 1944-02-21
Abstract: 602,308. Punching. DAYTON ROGERS MANUFACTURING CO. Feb. 21, 1944, No. 3200. Convention date, Aug. 18, 1942. [Class 83 (iv)] [Also in Groups XXIII and XXIV] A punch press comprises a lower ram carrying a die, a punch mounted in the upper part of the press in alignment with the die and a stripper plate yieldably mounted in the upper part of the machine and surrounding the punch, said punch, stripper plate and the means for mounting the punch being so constructed that when the press is inoperative the lower end of the punch is visible to an operator standing in front of the machine with his eyelevel above the lower end of the punch. The die 28 is supported on the upper end of a ram 21 operated through a pitman 25 from a shaft 5 adapted to be coupled by a clutch to a fly-wheel 6 driven by a motor 7. The ram projects upwardly through the bed-plate 4 of the machine. A frame 24 secured to the bed-plate supports a punch holding block 37 which is secured in a recess in the member 24 by means of screws such as 39 by which the block is capable of limited adjustment in a horizontal plane to position the punch 34 accurately  relatively to the die 28. A counterbore 42 in  the block 37 houses a punch-holding cage in  engagement with a flange 49 on a vertical stem 51 screwed to the block 37. Rotation. of the stem by a hand wheel 61 serves to adjust vertically the punch 34 which is secured within the cage by a spring-actuated ball 401 and which may be removed for charging by means of a knockout pin 50 extending through the stem 51. Surrounding the stem is a sleeve 53 carrying a resilient element 59 clamped between' upper and lower washers 57, 56 by means of a nut 62 on the upper end of the stem. Rods 64 depending from the lower washer 56 carry a stripper plate 63. Block 37 has a cut-out portion 69 towards the front of the machine which co-operates with a re-entrant notch 68 in the stripper plate to give the operator a clear view of the punch as indicated by the arrow 71 in Fig. 2. The work 109 in which holes are to be punched is frictionally held in a recess in a strip 111 secured to the underside of a jig plate 106 and the jig plate and attached work are manually inserted between the punch and die over side safety walls 104 and a front safety wall 114 of such a height that the operator's hands are kept out of danger. The actuation of the machine is controlled electrically and unless the wall 114 is in its upper position, the circuit is interrupted as by a switch 121 shown in Fig.' 14. Within the stripping plate 63 are arranged the windings 72 of three electromagnets with two contacts 75 projecting slightly from the lower surface of the plate. The operator raises the jig plate until the end of the punch enters a hole 107 therein and the plate completes the circuit across the contacts 75. The jig and work are then firmly held to the stripper plate by the energizing of the magnets and at the same time a solenoid 83 operates to complete a circuit through a solenoid 18 which actuates a lever 14 to allow a spring- operated bolt 12 to couple a hub 11 secured to the shaft 5 to the hub of fly-wheel 6 and so operate the ram. After the hole has been punched, a cam 87 on the shaft 5 actuates an arm 86 of a contact breaker to break the circuit through the electromagnets in the stripping plate and also through the solenoids 83 and 18, whereupon a spring 17 actuates the lever 14 to withdraw the bolt 12. The waste removed from the work by the punch is removed through a bore 20 in the ram. Specification 602,367 is referred to.