GB916721A - Punch-carrying plunger assembly for plunger press - Google Patents

Abstract

916,721. Making eyelets; cupping. TEXTRON Inc. Aug. 16, 1961, No. 29526/61. Classes 83 (2) and 83 (4). A punch-carrying plunger assembly for use in a cupping press for making eyelets comprises a pair of upper and lower toggle links which are pivoted together and to said plunger and mounted in an elongated slot in the lower end of said plunger, said punch being secured to said lower link, cam means secured to the press frame for rotating said upper link thereby forcing said links from a position at an angle to each other to a straight line toggle position whereby the effective length of said plunger will be increased during its downward stroke and said punch will be caused to travel farther than the plunger which supports it. The press comprises a frame 11 mounted on a base 10, the frame carrying a cam-shaft 12, the cams of which engage a plurality of rollers 15 mounted in boxes 44 which engage the heads of standard plungers 46 and a special long stroke plunger 46a. Plunger lifter cams 14 are also mounted on the cam-shaft 12. The lifter cams operate spring-loaded lifter rods 17 which carry the roller boxes 44 on arms 45. The cam-shaft is rotated through pinions 27, a flywheel 28 connected to a clutch 29 and a pulley 32 by a motor 33. A brake 35 is carried on an arm 34. Each lifter rod is provided with an adjustable friction bearing 38 attached to the press frame by depending arms 39. The long stroke plunger 46a has a vertical slot 51 terminating in a hollow bottom section 52 within which is a sliding member 52a which carries the punch 54. The lower toggle link 58 is pivoted to the sliding member 52a. The upper link 57 is pivoted to the lower link and pivotally secured to the plunger 46a by a pin 59. A cam block 63 is attached to the press frame for engaging the upper link. In operation, the plungers 46, 46a are continually reciprocated by the operation of the cams 13 and 14. On the downstroke of the plunger 46a the upper link 57 is rotated counterclockwise by its engagement with the stationary cam block 63 and the convex surface 66 until both links 57 and 58 are in a straight line position. Surfaces 70, 71 on the lower link 58 are confined by a bearing surface 68 and ensure alignment of the links during the deep drawing operation of the plunger 54. On the upstroke of the plunger 46a the upper link engages a concave insert 64 on the cam block 63 to break the straight-line toggle by rotating the upper link clockwise until the links regain their original positions. The stroke of the plungers is adjustable by moving the position of the lifter arms 16 on the lifter rods 17. The plungers and lifter cams are lubricated by cam tassles saturated by a mixture of white lead and oil. The long stroke plunger 46a may be installed at any station of the multi-stage press.