Patent GB-301757-A (GB)
Title: Improvements in and relating to clutch operating mechanism for transmitting rotationfrom one shaft to another
IPC: F16D23/12
Filed: 1927-09-02
Abstract: 301,757. Potter & Johnson Machine Co., (Assignees of Curtis, M. S.). Sept. 10, 1926, [Convention date]. Divided on 277,322. Lathes. - In a lathe having a toolcarrying slide which is automatically reciprocated, e.g. by a cam drum, to carry the tools to and from the work mounted in a rotary chuck, means are provided for synchronizing the movements of the parts of the machine, such means including a clutch connecting two rotary shafts and automatic clutch shifting means which ensure that the shafts are always connected and disconnected in the same angular relations. The lathe comprises a bed 10 supporting a saddle 13 which is reciprocated to and from the chuck 12 by a cam drum 14 acting on a roller under the saddle, the roller being carried by an adjustable slide to vary the stroke in relation to the work. The drum is driven through worm gearing 91. and bevel gearing 88 from a feed shaft 15 which is rotated in synchronism with the lathe spindle or from a constant speed pulley. A dog drum 27. which controls the spindle speeds, is also driven from the shaft 15 through bevel gears 84 and worm gearing 86. Secured to the saddle 13 by bolts and dowels is a thin platten 97 to which one or more tool holders are adjustably secured The tool holders, which are attached in the required positions on the platen before the latter is secured to the saddle, each comprise a base portion 98, Fig. 8, in which is rotatably mounted a helical cam 100 engaging a roller 102 on the tool-carrying slide 99. The cams 100 are rotated by one or other of two shafts 103, 104, Fig. 1, the shafts being connected by bevel gearing 105 and the shaft 103 being driven by gearing 125, shaft 124, clutch 128, elongated pinion 123 and reversing gearing operated in a timed cycle from the feed shaft 5. The pinion 123 is driven in opposite directions by a clutch-pinion 135, Figs 1 and 4, rotatable but axiadly fixed on a shaft 136 which is non-rotatable but moved axially by a yoke 137 and a cam 138. The two gears 132, 133 with which the pinion 135 is made to clutch are rotated continuously in opposite directions through gear trains 131, 129 from the shaft 15, the cam 138 being driven intermittently from the gear 133 by a pin 140 thereon engaging at each revolution with a four-slot Geneva wheel 141 carrying opposed pins 143 meshing with the teeth of a gear 144 to which the cam is attached. A fixed pin 148 engages a radial slot in a flange 146 of the clutch gear 135 when the latter is in the neutral position and the engaging clutch faces have each one tooth and recess respectively, the action being such that the clutch gear always disengages from either of the gears 132, 133 in such a position that the slot is opposite the pin 148 and also moves out of neutral position with the clutch parts ready to engage either of the gears, i.e. the shafts 15 and 124 are always connected and disconnected in the same angular relation. The cam 138 has straight portions for maintaining the clutch gear 135 in the forward, reverse or neutral positions, the changes through neutral always taking place while the cam is receiving its intermittent rotation and the length of the forward part of the cam being always equal to the length of the reverse part so as to withdraw the tools to their initial positions.