GB933040A - A press tool for use in punching holes - Google Patents

Abstract

933,040. Punches. E.M.B. CO. Ltd. May 28, 1962 [July 6, 1961], No. 24435/61. Class 83 (4). A press tool comprises a housing and a punch holder mounted for limited sliding movement therein, resilient means between the housing and the punch holder which urge the punch holder to a position in which a punch supported thereby projects to a maximum extent from the housing, and releasable catch means for retaining the punch holder in a position in which the punch projects to a minimum extent from the housing, arranged so that when the catch is released the punch engages the work material to enable it to be correctly located beneath the punch, and the catch is operated on actuation of the press to lift the punch from the material on the return stroke of the press. The housing 10 is secured in the press ram and has a bore 11 in which slides a punch holder 14. A compression spring 19 urges the holder downwards in the housing. A spring-pressed key 20 is mounted in the stem of the punch holder, and when the holder is in its uppermost position the key enters a recess 22 in the housing. A manually operated cam 23 forces the key back against the springs 21 when it is desired to release the punch. The upward movement of the punch holder is limited by the engagement of the shoulder 17 with the shoulder 13, and the downward movement by a flange 18 on the punch holder. The cam 23 also has a lip which engages the flange 18 so that the punch holder can be raised slightly against the spring 19. A punch 25 is clamped in the holder by a screw 27, and there is a stripper 28 secured to a member 29 which is attached to a stationary part of the press. A die 32 is mounted in a holder 31. Both the punch and die may be keyed to prevent rotation. Operation.-With the punch-holder in the lowest position the work material is positioned under the punch, the cam 23 being operated if necessary to relieve the pressure of the punch on the material. When the press is actuated the spring 19 is first compressed and then the punch-holder and housing move together and cause the punch to penetrate the work. At the same time the key 20 enters the recess so that on the return stroke of the press the punch is raised above the stripper 28. In a modification the stripper is resiliently connected to the housing. A manually operable die ejector may also be provided and comprises a lever operated tubular member mounted under the die.