Patent GB-619533-A (GB)
Title: Reversing feed gear shaping machine and method
IPC: B23F5/16
Filed: 1946-07-16
Abstract: 619,533. Gear-cutting. FELLOWS GEAR SHAPER CO. July 16, 1946, No. 21245. Convention date, Aug. 2, 1945. [Class 83 (iii)] [Also in Group XXXVII] The direction of rotation of a gear-shaped planing cutter and blank are reversed periodically so that the wear on the leading and trailing edges of the cutter teeth are equalized. The cutter C, Fig. 1, is secured to a spindle 10 rotatable in a carriage 11 and reciprocated by a lever 14 which has a gear segment engaging an enveloping rack 16 on the spindle. The lever is oscillated by an adjustable connecting rod 17 connected to a radially-adjustable crank-pin on a shaft 20, Fig. 4; fast and loose pulleys 21, 22 are mounted on the shaft 20 and driven from a main driving motor by a belt that can be shifted by a fork 60 operated by a rod 61 which is spring-loaded towards the loose pulley 22. When moved forward to shift the belt to the fast pulley, the shifter rod is secured in position by a latch lever 81, Figs. 1 and 8. A feed motor 36, Fig. 15, rotates the cutter spindle through worm gearing 26, 24 and, through change gearing 43, drives a shaft 44. The shaft 44 rotates the work-spindle through bevel gears 45, 47, a shaft 46, reversing gears 48, 49, 50, and worm gears 32, 31, and also rotates a depthfeed cam 33 through a reversing clutch 52. The work-spindle drive is reversible in order that both internal and external gears may be cut, and the cam drive is automatically reversible by the clutch 52 so that the cam always rotates in the same direction, irrespective of the direction of rotation of the feed motor. A roller 66, Fig. 8, adjustable relatively to the carriage 11 by a rack 67 and a pinion 68, is held against the feed cam 33 by a weight 35, Fig. 3, that rotates a pinion 73 engaging a rack 74 connected to the the carriage. The rise 78 of the cam slowly feeds the carriage to increase the depth of cut during a series of planing reciprocations. Rack teeth 90, Fig. 3, on the belt shifter rod 61, rotate a pinion 88 which, through a pawl and ratchet 92, cam 94, and linkage 95, 99, Fig. 7, operates the clutch 52 every time the rod is moved forward. For relieving the work W from the cutter during its return strokes, a carrier 30, Fig. 4, for the work spindle, is pivoted at 103 on a lever 104 rocked about a pivot 105 by a cam 108 on the shaft 20, through a bellcrank lever and a rod 115. The relief movement, which is along a line at an angle to the line of centres of the cutter and work to avoid interference betweeh the teeth, is guided by a block 116 engaging a shoe 117 mounted in a recess in the work spindle carrier. The angle of the block is adjustable by screws 122, 123 and is inclined in the direction appropriate to the direction of rotation of the cutter and work, by a motor 124 driving a shaft 125 having a worm 126 which engages teeth on the block. The worm 32 driving the work spindle is mounted in a housing 128, Fig. 3, pivoted at 130, so that the worm can be disengaged from the spindle worm-wheel 31. Operation.-The main motor for the driving belt is started by a push-button switch which is held closed by a shunt circuit. The belt shifter rod is pulled forward to shift the belt to the fast pulley 21 and to close a switch 63, Fig. 15, so that the feed motor 36 rotates the cutter and work in one direction, and the motor 124 places the guide block 116 at the appropriate inclination. When the work is finished, a cam 64 on the feed cam shaft momentarily closes a switch 65 controlling electrical relays, and a stud 86 on the feed cam releases the latch lever 81 so that the belt shifter rod moves the belt to the loose pulley and opens the switch 63 to stop the motors 36 and 124. A new blank is placed on the work spindle, and on the forward movement of the shifter rod, the switch 63 is again closed but the relays have altered the current supply to the motors 36 and 124 so that they are reversed to drive the work and cutter reversely and set the guide block at the opposite inclination. A stop switch is provided for stopping the whole machine. The electrical control and circuits are described (see Group XXXVII). Specification 435,702 is referred to.