GB958738A - Grinding machine - Google Patents

Abstract

958,738. Ratchet gear; securing gearwheels on shafts. CINCINNATI MILLING MACHINE CO. Nov. 13, 1962 [March 29, 1962], No. 42825/62. Headings F2Q and F2U. [Also in Division B3] In a grinding machine (see Division B3) a shaft 67 is rotatable in bearings located in a bushing fixed in a portion 48. An overrunning sprag-type clutch engages with a clutch bushing 72 keyed to the shaft 67. The clutch comprises a casing 73 rotatable relative to the portion 48 a limited amount. Inside the casing is a cylindrical sprag pin 74 held in close proximity with the bushing 72 by an adjustable plunger 75. The sprag pin 74 is held in simultaneous contact with the face of the plunger 75 and the bushing 72 by a spring-loaded plunger 76 urging the sprag pin 74 toward a fixed pin 77 attached to a bracket 78 secured to the portion 48. The longitudinal axis of the plunger 75 is slightly offset from the centre of the shaft 67 so that the space between the bushing 72 and plunger 75 is wedge shaped. When the casing 73 is rotated clockwise the sprag pin 74 is wedged and rotates the shaft 67, the amount of clockwise rotation being limited by the clearance between the pin 77 and the end of the cavity in the casing 73. When the casing 73 is rotated counterclockwise, the sprag pin 74 is released and is caused by the spring-loaded plunger 76 to follow back round the bushing 72 until it engages the fixed pin 77 which causes the plunger 76 to shift slightly and allow the pin 74 to stop slightly before the casing 73 is stopped. This moves the sprag pin 74 out of simultaneous contact with the plunger 75 and the bushing 72, so that the bushing 72 and shaft 67 may be freely rotated in either direction. Thus a slight relative rotation between the bushing 72 and casing 73 is required to move the clutch from a released position to an engaging position, the amount of movement being varied by adjusting the plunger 75. A spring 81 in compression between the portion 48 and the casing 73 urges the latter counterclockwise to the released position. A shaft 98 has a flat-sided end 98a loosely received in a sleeve 99 rotatably mounted by bearings in a depending yoke 48a. A gear 102 is integral with the sleeve 99. A roller collar 107 fixed to the end of the sleeve 99 has axles 109, 110, 111. A double ball bearing roller 112 rotatable on journal diameter 109a of axle 109 engages the flat surface of the shaft 98, and single ball bearing rollers 113, 114 rotatable on journal diameters 110a, 111a of the axles 110, 111 engage the cylindrical surface of the shaft 98. The journal diameters 109a, 110a, 111a are round but eccentric to the longitudinal axes of the axles. Rotation of the axles, which are releasably held in the collar by set screws, preloads the rollers 112.