Patent GB-167441-A (GB)
Title: Improvements in tooth forming machines
IPC: B23F1/04
Filed: 1920-03-25
Abstract: 167,441. Stevenson, G. E. March 25, 1920. Gear-cutting. - Teeth are cut simultaneously all round a blank by a number of reciprocating cutters 65 operated by means of a frame 32 which is reciprocated by a connecting-rod 34 from a driven pulley 47 through a hand-operated clutch (not shown) arranged, however, so as not to effect the drive of the shaft 40 by the pulley 47. The main tool-head 31, shown conical as applied to bevel-wheel cutting, has a number of equidistant radial slots 62, in each of which is a radially-movable carrier 63 holding a cutter slide 64 of the polygonal section shown, to prevent vibration. The cutter 65 is fixed by a set screw 66 to a pivoted spring-pressed socket 67, mounted in the slide 64. These slides are connected by links 72 with the frame 32, and the carriers 63 are moved by cam-grooved discs 76 on a shaft 78, which is rotated by the action of a cam-groove 84 in a cylinder 85 driven by bevel and worm gearing from the shaft 40. The work-turret 30 is mounted on a vertical post 28 on a slide 29, and is rotated through a worm 110 and bevel-gearing by the shaft 40. A clutch interposed in the drive from the worm 110 automatically connected and disconnected according to the position of the turret as it is reciprocated by a link 118 and a camdisc 88 on the shaft of the cylinder 85, the turret being thus indexed whilst out of the operative position. Corresponding in position with the two work-spindles 97 are locking-lugs 123 by means of each of which in turn the turret is locked during the cutting operation by a spring bolt 128 operated by the cam 88. The blanks are held on the reduced split end of each spindle by a wedge-ended shaft 137, moved longitudinally by a bevel-wheel 139 on the inner threaded end of the shaft 137 On one side of the post 98 is mounted a bevel. wheel 141, which is adapted to engage alternately with each wheel 139 and is put into driving con. nection with the shaft 40 by a clutch 153 operated by a pedal 149, which is depressed by'the operator after putting a blank on the end of the spindle 97. The blank is thus locked on the spindle, and is unlocked again after the cutting operation by the action of a toothed segment 102 which engages each of the spur-wheels 143 as the turret turns and thereby moves the shaft 137; the finished blank is then pushed off the spindle by an arm 156 engaging a stationary cam 103. To obtain the correct curves of the tooth faces the spindle 97 is oscillated during the cutting action by means of a depending toothed segment 161 engaging a toothed segment 163 moved under the control of a cam-groove 167 in the cylinder 85, the tools being finally drawn clear of the teeth by the combined action of the cam-grooves 84, 167. Fig. 16 shows the developmemt of these grooves, with a diagram of the relative positions of the tool-carrier and the work. In the cutting position, a bolt 168, which otherwise locks the segment 161, is tripped by a projection 173. A lug 174 on the cylinder 85 is arranged to hold the clutch driving the frame 32 out of action during the indexing motion of the turret.