Patent GB-165089-A (GB)
Title: Improvements in and relating to bevel gear cutting machines
IPC: B23F1/04
Filed: 1921-06-10
Abstract: 165,089. Gleason Works, (Assignees of Stewart, A. L., and Hood, E. C.). June 21, 1920, [Convention date]. Gear-cutting.-In a bevelgear cutting machine of the templet - controlled planer type, a single templet may be employed to cut all gears having the same pitch-cone angle by adjusting the templet according to the angle subtended by a tooth at the centre of the circle on which the profile is developed. The invention is also applicable to spurgear cutting, each templet being in this case adapted to cut all gears of the same pitch diameter. In Fig. 1, the blank-spindle 34 having any suitable indexing mechanism 36 is carried on a standard 32 radially adjustable to bring the apex of the pitch cone to the centre of the machine by means of rack gearing 39<b> and supported on centrally pivoted bed 37. The latter may be adjustably secured by bolts 43 to an arcuate rail 45 oscillated to effect the feed and withdrawal of the blank, a scale 49a being provided to indicate the angular position of the work-support. The feeding- mechanism comprises a lever 56, the underside of which carries an adjustable block 59 engaged by a trunnion on a second lever 63 having an extension carrying a roller engaging a cam 67 on a feed-shaft 68. The tool guides 69, 70 carry reciprocating tool-carriers 77, 78 having racks 79 meshing on opposite sides with a pinion 80 on an oscillating shaft 75. The tools 94 are located in blocks 85 carried in heads 83, each tool being adjustable to provide cutting clearance by means of an arcuate guide 84 concentric with the cutting- edge, the setting being indicated by a suitable scale. The tool-blocks are cut away at 88 to receive adjustable tool posts 89 pivoted on spindles 91. Each tool guide carries a rack 96 engaging a pinion 97 which, during the reciprocation of the tool-carriers, operates through yieldable friction. And other gearing to swing the tool post about its pivot 91 to withdraw and restore the tool at the beginning of the return and cutting strokes respectively. The tool guides are further provided with arcuate rack-bars 118 engaging opposite sides of a pinion 120 on a shaft 121 which carries a toothed sleeve engaging a rack-bar 135 having at its lower end the templet roller 136. The tool guides may be manually adjusted by means independent of the templet-controlled rack-bar, and a spring device is provided for keeping the roller in firm contact with the templet. The templetholder is secured to the feed-rail 45, and carries a straight-edged roughing-templet 149 and a finishing-templet 137, either of which may be positioned by rotating the holder on its spindle, the correct settings being indicated by a spring- pressed latch 164. Each templet is supported on a segmental plate coacting with arcuate guiding-surfaces and set to the required angular position in a. vertical plane bv means of fine and coarse scale-adjustments. The machine is operated from a pulley-driven shaft 177 which drives through change-speed gearing 182, Fig. 23, an adjustable crank-disc 186 provided with a connecting-rod 195 which has rack teeth 196 engaging a pinion on the shaft 75 to reciprocate the tool-carriers. The feed-shaft 68 is driven through bevel and worm gearing from a clutch shaft carrying clutch sleeves 202, 206 the former being driven from the change-speed gear and the latter at higher speed from a pinion on the main shaft. Lugs on a disc 242 secured on the feed-shaft operate the clutch automatically to transmit slow and fast speeds respectively to feed and withdraw the work from the tools. Further means are provided for disengaging the power feed and manually operating the feed-shaft for. setting the machine from a hand-crank 255 and to avoid the possibility of collision between the reciprocating tools due to improper adjustment the feed is automatically disengaged whenever the tool guides swing into dangerous proximity to each other. An adjustable overhead brace comprising arms 272, 274 pivoted at 273 co-axially with the machine centre, connects the upper ends of the work and tool supporting-standards. Fig. 32 shows examples of difffferent gears having the same cone angle which may be cut from the same templet, the tilt of which is varied according to the back cone tooth-angle A.