GB542741A - Improvements relating to machine tools and to cutter relieving means therefor - Google Patents

Abstract

542,741. Gear-cutting; shaping. FELLOWS GEAR SHAPER CO. Oct. 8, 1940, No. 15023. Convention date, Oct. 16, 1939. [Class 83 (iii)] A shaping or like machine, particularly a gear generator of the reciprocating pinion cutter type wherein a work blank such as W, Fig. 6, has teeth generated by a reciprocating cutter C while the gear and cutter rotate in timed relation has means for effecting the relative relieving movement between the cutter and the work on the non-cutting strokes at a variable angle x to the line joining the centres c, w so that external and internal gears of different pitches, pressure angle, &c., may be cut without causing rubbing on the non-cutting strokes at the entering side m of the cutter teeth. In Fig. 1 the work W is mounted on a horizontal axis and the cutter C is mounted on a spindle 10 which is reciprocated from a main shaft 12 through a crank 13 racktoothed connecting rod 14 pinion 16 and rack sleeve 17 mounted between thrust bearings the sleeve being arranged to permit lateral spindle movement. Generating movement is imparted to the cutter by worm gearing 24 through a guide sleeve 26 co-acting with a guide on the cutter spindle. The cutter assembly is mounted in an adjustable carriage 29. A ring 30 is mounted concentrically with a bearing sleeve 31 for the hub of worm wheel 25, the sleeve being mounted to swing on trunnions 32, 33 in the ring 30. The axis N, N of the trunnions may be angularly adjusted by means of slots 35 and bolts 34 this adjustment being indicated by a scale co-acting with pointer 42. At its outer end the spindle fits in a bushing 43 having shoulders 44, Fig. 3, which engage between abutment blocks 45 which have convergent stop faces. The blocks 45 are adjustable to vary the limit of movement of the bushing 43 to determine the precise cutting position. The taper of the stop faces also allows withdrawal of the cutter spindle at different angles x within the limits of the angle of taper. The relief movements are effected by a spring 48 and are controlled by a cam 57 acting through a lever 55 and rod 50 on the bushing 43. The cam is so timed that the spindle is shifted into its cutting path before each cutting stroke and withdrawn at the end of such stroke. The bushing is guided during its movement by an angularly adjustable block 61 having at one end a plane surface 64 which is adjusted to the required angle x. The surface 64 engages the plane surface at a follower block 67 which seats in a cylindrical bearing surface secured to the bushing. A spring 70 holds the guide surfaces in contact and ensures that the bushing moves in the path determined by the setting of the block 61. The trunnion axis N, N is given the same angular setting as the block 61. Specification 500,928 is referred to.