Patent GB-643094-A (GB)
Title: Machine for cutting or grinding spirally grooved cams or the like
IPC: B23F13/04
Filed: 1948-01-08
Abstract: 643,094. Milling helical cams &c. ROSS GEAR & TOOL CO. Jan. 8, 1948, No. 659. Convention date, July 19, 1939. [Class 83 (iii)] [Also in Group XXIII] A machine for cutting or grinding helicallygrooved cams or the like comprises a table 2 for supporting the blank C, a rotary tool G which is mounted eccentrically on a spindle 5 rotatable about an axis normal to the blank axis to engage the blank C as the spindle rotates, and a cam M which is moved rectilinearly at a speed proportional to the rate of blank rotation and presents, laterally of its path of movement, a surface M<SP>1</SP> engaged by a follower 38 operatively connected to the spindle to rotate it. A machine is described for cutting steering-gear cams of the type described in Specification 462,486, [Class XXIV]. The camblank C, Fig. 4 is rotated by a two-speed electric motor 21, Figs. 2 and 3, driving through belting, a chaft 12, a flexible connection 13, a shaft 14, a gear 16, pawl 17a, hand wheel 17, worm 15, worm wheel 18 and the shaft 8. The cutter G is rotated by a self-contained electric or pneumatic motor or other means. An electric motor 67, Fig. 9, is connected directly to the cutter spindle. The cutter and its motor are mounted eccentrically on a spindle 5 which is rotated simultaneously with the blank C by a gear 23 on the shaft 12. The gear 23, through change-gearing rotates a screw 32 to move a slide 34 transversely of the machine. The slide 34, Fig. 3, carries a cam M with which is engaged a roller 38 carried on a slide 43 moving in fixed guides 40 and carrying a rack 42 to engage a gear 6 on the spindle 5. The rotational movement thus imparted to the shaft 5 moves the tool G in an arcuate path across the face of the blank. The cam M, which may be of any required form, is mounted on a circular slide 37 adjustable about a pivot 34a which coincides with the follower 38 in its midposition. The roller 38 is maintained in contact with the cam by a weight 44 acting through a chain 45, gears 46 and 6 and the rack 42, thus also taking up any backlash. The depth of cut can be varied by a cam 55, Fig. 2, which is mounted on the spindle 5 and which is maintained in contact with a follower 57 by a weight 58. Axial movement of the spindle 5 is permitted by bearings 4a, 4b on a slide 3 carrying the spindle. The slide 3 is adjusted initially by a screw-shaft 51. Initial adjustment of the blank is permitted by releasing the pawl 17a. In operation, the motor 21 is actuated to traverse the cutter completely through the blank, a switch 35 being then actuated by a stop 36a on the slide 34. The cutter is then withdrawn by the screw 51 and the motor again actuated in a reverse direction and at a higher speed to return the parts to their initial positions, a second switch 35 then being actuated. Tailstocks ; lathe centres and carriers.- The blank C, Fig. 4, is mounted in ball-bearings in the headstock spindle 8 and tailstock spindle 9. The latter is advanced to clamp the blank by a manually-operated rack and is itself clamped in position by screw-operated wedges. The blank is driven from the spindle 8 by a driver 8b engaging a specially-cut slot C<SP>1</SP> in the blank.