GB1192544A - Improvements in or relating to Drive Mechanisms for Imparting Intermittent Rotary Motion to a Shaft - Google Patents

Abstract

1,192,544. Metal working press. SAMUEL GRIFFITHS (WILLENHALL) Ltd. 3 Aug., 1967 [17 May, 1966], No. 21863/66. Addition to 1,103,599. Heading B3H. [Also in Divisions B5 and F2] A flywheel press having a tool carrying ram (21) (Fig. 1, not shown) reciprocated by a crank, cam, or eccentric on a shaft (22) includes a planetary change-speed gear (25) between the flywheel and the shaft (22), the shaft (22) being braked automatically when the gear (25) is not engaged. The gear (25) comprises an input planet carrier 33 which is belt driven from a motor (28), forms the flywheel, and carries at least three sets of planet pinions 43, 44, 44a meshing respective sun gears 54, 58, 58a, one sun 54 being secured to an output shaft 29 connected to the shaft (22) by gears (14, 15) and the other suns 58, 58a being secured to respective shafts 59, 59a coaxial with the shaft 29. Suns 58, 58a are holdable by respective pneumatically applied disc brakes 16, 16a to form reaction members for different gear ratios, while shaft 29 is holdable by a spring-applied disc brake 11, only one brake being engaged at any time. Pressure air supplied to one or other of brakes 16, 16a also releases the brake 11, a two-way valve (105) (Fig. 5, not shown) being used to select one or other of the brakes 16, 16a. The ratio may be changed during a cycle of operation, e.g. for rapid advance of the tool to the workpiece, slower forming action, and rapid withdrawal, by controlling the two-way valve from a cam switch (109) (Figs. 1, 2, not shown) driven from the shaft (22). Brakes 16, 16a are identical. Pressure air supplied to an annular space 82 of a cylinder 80 urges a piston 81 leftwards (Fig. 4) to act via pins 90 to grip discs 66, splined to a hub 65 secured to the shaft 59, between discs 73 splined to a casing section 68. Springs 88 act on a flange 87 of piston 81 to release the brake when air pressure is removed. Brake 11, comprising a disc 76 splined to a hub 74 which is splined to the shaft 29, between a pair of discs 93 splined to a casing section 190, is applied by pairs of compression springs 102 reacting on a flange 95 of casing 190, and acting on a pressure plate 101. To release the brake, an annular tube 99 is inflated to move rightwards a disc 97 secured to a cone 100 carrying the pressure plate 101.