Patent GB-189504-A (GB)
Title: Improvements in gear grinding machines
IPC: B23F5/08
Filed: 1921-08-24
Abstract: 189,504. Garrison, O. Aug. 24, 1921. Gear-wheels, grinding and trueing teeth of.- In a machine for grinding the teeth of gearwheels, the grinding-disc is reciprocated axially of the work and operates at successive reciprocations upon corresponding sections of successive teeth, the gear-wheel being stationary during grinding and indexed between reciprocations, until all the teeth have been ground. The gearwheel is then rolled transversely of its axis, or cross-stepped, under the control of a master gear and rack, and a further section of the tooth operated upon. This is repeated until the whole surface of all the teeth is ground, when an automatic stop-motion arrests further lateral feed and indexing. The machine comprises a base B, upon which are mounted a grinding-head C, a workhead D, and a wheel dresser E. Machine base. The base carries a main shaft 5, which is driven through a clutch by a pulley 7. Inside the base is a shaft 12 driven from the shaft 5 and reciprocating, through a crank 14 and link 15, a ram 26 carrying the grinding-head. The shaft 12 also drives a divided shaft 20, 21, Fig. 4, connected by a clutch 22, 23, the clutchpin 24 of which is operated by a lever 24<c>; the shaft carries cams 50, 50<a>. Grinding-head. This is mounted on a block 25, Fig. 4, adjustably secured to the ram 26. The grinding-disc 34 is carried by the head, which is adjustable vertically on the block by a screw provided with a graduated dial 33. Work-head. This is carried by a plate 51<a>, which is supported on the base B by a block 51, Fig. 4, and is movable thereon in ways 51<b>. The work 52 and a master gear 53 are mounted on a spindle 54 supported in a bearing 55, the spindle also carrying a collar 57, on which is formed a cam 105. In order to align the work and the master gear, a one-tooth aligning-bar 66, Fig. 2, is provided, which is mounted, on a pivoted head 67, in predetermined relation to the master gear and may be moved into engagement with the teeth of the gear-wheel 52. The head 67 is adjustable to suit the diameter of the work. Indexing the work. The indexing-mechanism comprises a vertically movable frame 76, Fig. 2, having adjustably mounted thereon a master rack 78 adapted to mesh with the master gear. The frame has adjustably secured to its lower end a plate 80 carrying a roller 83 engaging the cam 50; thus, on each revolution of the shaft 21, the frame 76 is raised and lowered and the rack is moved out of and again into mesh with the master gear, which is indexed one tooth space in the interval. The rotation of the master gear is produced through a friction ratchet mounted on the hub 85 of the master gear and links 87, 89, 90, 92 and a lever 88, by the cam 50<a>. Cross-stepping the work. This is effected by a rack 94 which is mounted on the block 51 and along which moves a gear 95 carried by the plate 51<a>. The gear 95 is rotated by a friction pawl 100 operated, through a link 103 and a lever 101 by the cam 105. Thus, upon each complete rotation of the work spindle, the work head is moved transversely one step, the extent of movement being determined by the setting of a screw 103<a> carried by the link 103; the cross-stepping may be operated manually by a hand-lever 99<a>. The cross-stepping and indexing are automatically stopped, after completion of grinding, by disengagement of the clutch 22, 23, this being brought about by the release from a trip-lever 110 of a spring-pulled lever 106 connected to the lever 24<c>; the trip-lever is moved by a lug 112 adjustably mounted upon the work-head plate 51a. A connection is provided between the cross-stepping and the main control lever 119 of the machine through a shaft 115, Fig. 1, carrying an arm 118 adapted to engage the lever 119 and an arm 117 adapted to engage the lever 106. Grinding-disc dresser. This is shown in Fig. 5, and comprises diamonds 137, 138 mounted on a slide 136 carried by a post 130, which is supported in a post 125. The diamonds are adjusted by a screw 141 and the slide is operated by togglelevers 139 and a crank-shaft 140.