Patent GB-669207-A (GB)
Title: Improvements relating to gear shaping machines
IPC: B23F5/16
Filed: 1949-08-23
Abstract: 669,207. Gear-cutting; planing. FELLOWS GEAR SHAPER CO. Aug. 23,1949 [Sept. 16, 1948], No. 21907/49. Class 83 (iii). [Also in Group XXIV] In a gear-shaping machine having rotatable work and cutter spindles, means for reciprocating one of the spindles comprises a pitman 64, Fig. 14, which is coupled with a crank 62 and has a screw element 64a meshing with a gear 65 on an axis transverse to the pitman, and transmission mechanism between the gear and the spindle, the screw element 64a being adjustable about its axis with respect to another part of the pitman and having its axis radial to the crank. Change-speed gearing; reversing.-A single electric motor 36, Fig. 22, rotates the cutter and work spindles, which respectively carry worm-wheels 110, 99, through twelve-speed gearing 42-56. A hand-lever 229, Figs. 1 and 14, operates the speed-changes through two barrel-cams 225, 218, Fig. 3, controlling shifter-rods, the appropriate cam being selected by a knob 240 and the gear-speed being indicated by dials 234, 235. Spring-pressed balls 228, Fig. 14, assist in positioning the gears. Further speed changes are provided by gears 79-81, Fig. 22, selected by a four-position lever 262, Fig. 3. Change-gears 75, 76, and 92-96, are also provided. The drive can be reversed by a hand-crank 88 connected to bevels 83, 84. The cutter-spindle is independently reversible by bevels 102, 103, according to whether internal or external gears are to be cut. The worm-wheel 110 is engaged by a worm 109 which is adjustable for backlash and is situated on the same side of the spindle as the zone of cutting engagement. The cutter is reciprocated by the adjustable crank 62, Figs. 14 and 22, on the shaft 58. It can also be reciprocated manually by a hand control 250, Fig. 1; which is effective only if a lever 261 is held in position to engage gearing on the shaft 41, Fig. 22. The crank 62 oscillates a shaft 66 through the rod 64a, the shaft 66 having teeth engaging a circumferential rack 70, Fig. 3, on the cutter-spindle 35. Stroke indicators; cushioning.-The limits of the cutter-travel can be adjusted without altering the length of the stroke, indicated by a graduated scale, 63a, Fig. 14, by manually turning the rod 64a. The cutter-spindle is counter-balanced by mechanism 35a. Cutting helical wheels.-The cutter-spindle slides in guides 111, 112, Fig. 3, which are of helical formation when helical gears are to be cut. The cutter-carriage 34 is adjusted initially for cutting internal or external gears, along guides 33 by a nut which is rotated manually through a shaft 163 and which engages a screwed shaft 156. Feed-mechanism; beds, framings, etc.; stopmotions.-The cutter is fed to depth by moving the shaft 156 longitudinally by means of a toothed segment 158 controlled by a depth feed cam 155, a constant force being applied to the shaft 156 by a spring 193, Fig. 14, which is anchored to the machine frame and acts through a pinion 197, Fig. 3. In operation, rotation of the work-driving worm 98, Fig. 7, actuates, through a flexible shaft 203, a timing device, which, after one revolution of the work W, operates a solenoid to withdraw a catch 179, Fig. 14, to allow a roller 167 to engage a cam 61 on the shaft 58. The cam 61 advances a rod 171 to rotate a ratchet-wheel 176 by an amount determined by a stop 177. The wheel 176 rotates a second ratchet-wheel 189 connected with the depth feed-cam 155. The wheel 189 also rotates a carrier 199 on which dogs 204, Fig. 1, are adjustably mounted. The dogs actuate a switch 208 to release the catch 179 after each advance of the cutter. A fixed cam on the carrier 199 actuates a switch 212 to stop the machine when cutting is complete. The double ratchet-drive 176, 189 enables the depth feed cam 155 to be manually adjusted by a shaft 190 independently of the cam-drive. The work W is supported on a table 27, Figs. 3 and 7, which carries the worm-wheel 99 and is supported on the frame by a link 28 pivoted to the frame at 29 and by bearing surfaces 114, 115. The table may be swung clear of the superstructure of the machine, by a lever system operated by a lever 128, Fig. 1, the table being then supported by a roller 130 on a swinging arm 131. The table is relieved on non-cutting strokes by a cam 135, Fig. 7, which, through an adjustable arm 140, oscillates the table about the pivot 29. Teeth on the arm 140 mesh with a segment 143 which is mounted on the table and can be withdrawn by a handle 151.