GB860051A - Improvements in change-speed gearing for mechanical drawing presses - Google Patents

Abstract

860,051. Change-speed gear; friction clutches. WELDED PRODUCTS Ltd. Nov. 25, 1958 [Dec. 5, 1957], No. 37942/58. Class 80 (2). In a two-speed gear, intended particularly for a mechanical drawing press, the input shaft 4 drives a parallel output shaft 9 through low and high ratio pairs of pinions 7, 11 and 8, 12 respectively, and one of a pair of associated multi-disc clutches A, B on shaft 9, the low-ratio clutch A normally being disengaged and the high-ratio clutch B engaged, means being provided however to disengage clutch A and engage clutch B to render the low-ratio drive effective. In the arrangement shown the clutches are separated by a spacer disc 24, and the retaining plates of the respective clutches are pressed apart by groups of springs 30A, 30B, of which the former are stronger than the latter so that, normally, they maintain clutch A disengaged and, through a circumferential series of pins 28A in disc 24, maintain clutch B engaged, to render the high-ratio gear 8, 12 effective. To render the low-ratio gear 7, 11 operative compressed-air is supplied through passages 27, 28 in shaft 9 and disc 24, respectively, to act upon a diaphragm 26 and over-ride springs 30A, thus engaging clutch B and disengaging clutch A, the admission and release of the air being controlled by valves actuated by cams on shaft 9. When applied to a drawing press the low-ratio gear is operative during that part of a revolution of shaft 9 corresponding to the drawing operation, the high-ratio being operative during the remainder of the revolution, thereby increasing the effective stroke rate of the press.