Patent GB-529784-A (GB)
Title: Improvements in indexing mechanisms particularly for machines for producing gear wheels
IPC: B23Q16/06
Filed: 1939-05-26
Abstract: 529,784. Grinding machines. GLEASON WORKS. May 26, 1939, No. 15670. Convention date, Aug. 23, 1938. [Class 60] [Also in Group XXII] Indexing.-An indexing-mechanism, particularly for gear-cutting machines, has Geneva mechanism acting in conjunction with a locking-dog and index plate for determining the indexed positions and arranged so that the driving-pin of the Geneva mechanism enters a notch before the locking-dog is disengaged and vice versa, so that over indexing of the work is prevented. As applied to a non-generating machine the work spindle 15 carries an index plate 16 and a Geneva wheel 17. The former is engaged by a locking-dog 26 mounted on a lever, pivoted at 27, and urged into locking position by a spring plunger 29. The Geneva wheel is rotated after dis-engaging the dog 26 by a pin 35 carried on a head secured to a shaft 47. The head has a cam 36 coacting with a block 40 on the locking lever. The shaft 47 is continuously rotated from a shaft 66 and spur gear 65 and is reciprocated to bring the Geneva pin and the cam into operative position by a cam 50 and lever 51. The dog 26 is held against accidental dis-engagement by means of a rod 70 which engages behind a plate 38 on the locking lever, and is withdrawn against spring pressure by means operated from the lever 51, when the shaft 47 is moved forward just prior to indexing. In a modification for a machine of the generating type the work head 80 has bearings 82 for a spindle 81 carrying index plate 100 and Geneva wheel 101. The work has a long shank 83 and is gripped by a collet 84 closed by a spring 90 and released by a piston 98 and lever 95. Generating roll is imparted to the work through a bevel gear segment 105 secured to the head 106 of a ball bearing sleeve 107. The index locking lever 112 carrying a dog 115 is pivoted on a pin 110 in the head 106 is held in engagement by a spring plunger 118, and is dis-engaged by a roller 116 and cam 125 carrying the pin 132 of the Geneva mechanism. The cam is mounted on a sleeve 154 slidable on a stud and driven through gears 128 from an internal gear segment 130 on the work head. Thus as the segment 105 rocks the gear 129 rolls on segment 130 and rotates the cam 125. The movement of the cam into and out of operative position is effected through a guide member 137 pivoted at 136 in the work head and held by spring pressure so that a part 139 is pressed towards the segment 130. As the head 106 oscillates a roller 151 on a spring pressed lever 150 connected through a pin to the sleeve 154 rides on the guide surfaces of member 137. During the working roll the index mechanism is locked and the work is rotated by the segment 105 and the roller 151 rides on surface 138 of the guide member to maintain the unlocking cam and Geneva pin out of operative position. At the end of the movement the roller 151 clears the surface 138 and allows the guide member to be shifted by its spring to the position shown in Fig. 7. On reversal of the roll, the roller 151 now moves down the surface 140 and swings lever 150 into a position in which the cam and Geneva pin are operative and after further return movement cam 125 unlocks the index plate and the Geneva pin imparts the index movement after which the parts are re-locked. On the next generating roll the roller 151 again engages the surface 138 to withdraw the locking cam and Geneva pin. During indexing the plate and locking pin are moving in opposite directions so that the indexing time is reduced.