GB664888A - Gear finishing machine - Google Patents

Abstract

664,888. Gear-finishing machines. NATIONAL BROACH & MACHINE CO. Oct. 5, 1949 [Nov. 8, 1948], No. 25614/49. Class 83 (iii). [Also in Group XXIII] A method of finishing a gear consists in moving a rotatable tool L and the work gear W into meshing contact under light pressure and relatively locking them against such movement during finishing. The method involves taking a finishing cut of a predetermined amount on a gear, even if the gear is under, or over size. A machine for carrying out the method comprises an angularly adjustable head 12 carrying the lap L and a vertically-adjustable knee 15 carrying a reciprocable slide 20 supporting the work gear W. Separate motors rotate the lap and reciprocate the slide. The slide 20 carries a table 30 which may be rocked about a pivot 32 under the control of a cam 34 or locked by screws 36, 38, an angularly-adjustable table 42 and a pivoted table 50. The table 50 is pivoted at its rear to the table 42 and is urged upwardly by springs, adjustable for pressure, at the front of the table. The table 50 also carries a fixed screw 70 which supports a nut 72 having wedging faces 73, 74, a nut formed with pinion teeth 76 and a cam 77, and a freely mounted member 80 loosely supporting rollers 84 on undersize pins 83. The cam 77 engages the underside of an inverted U-shaped member 66 attached to the table 42. In operation, a fluid-operated piston 92, bearing rack teeth, is advanced to rotate the nut 76 and hence the cam 77 which releases the table 50. The springs are then free to advance the gear into mesh with the lap and the nut is advanced to lock the table, the member 80 rocking on its curved seating 78, if necessary, to allow the rollers 84 to be withdrawn or advanced into locking position. After a back and forth reciprocation of the gear, rotation is stopped and the piston 92 reversed to rotate the cam 77 and so withdraw the gear into loose mesh with the lap. The knee 15 may be fed independently between strokes and more than two strokes may be made. Alternatively, by actuating the piston 92 at the end of each stroke, an up-feed may be imposed, the final dimension being determined by an abutment limiting upward movement of the table 50. During initial setting-up, the central position of the table 50 may be determined by gauging marks or by mounting on the table a movable gauging stop having one or a series of steps, any one of which is engageable with a projection on the member 66. The knee 15 is then adjusted so that the lap is in correct engagement with a master gear on the table 50 when the latter is in its intermediate position. The crossed-axis setting is 3 to 20 degrees.