GB700136A - Method and means for copy-grinding - Google Patents

Abstract

700,136. Copy grinding ; trueing. FOUQUET, E. Sept. 24, 1951, No. 22352/51. Class 60 The grinding wheel 2A, Fig. 1, and the follower wheel 2B of an apparatus for copygrinding are of the same profile and diameter and have their diameters progressively reduced during the grinding of a work-piece P, the similarity of the profiles of the grinding wheel and follower roll being maintained. The reduction may be effected by a continuous trueing of both wheels by crushing rolls or by diamonds 25A, 25B, mounted on shafts 23A, 23B oscillated by a belt-driven crank 31, a connecting rod 29 and two forked members 28A, 28B. The latter two members are connected together by a ball-jointed rod 47 to ensure that the diamonds oscillate in unison. The shafts 23A, 23B are mounted in members 22A, 22B keyed to a shaft 19 and adapted to be tilted about the axis of this shaft to feed the diamonds to the wheels by a screw and nut feed device such as 36A, 39A operated by a pawl and ratchet from the reciprocation of the rod 47. The rate of feed may be adjusted by a tooth mask on the ratchet wheel. The grinding wheel and follower wheel are journalled in arms 1A, 1B, respectively and are rotated through belt drives 16A, 16B by electric motors 14A, 14B. Both arms are counterbalanced by a weight 13 and keyed to a shaft 3 mounted on one end of a support 5 oscillated about a fixed shaft 6 by a belt-driven crankshaft 8 and a connecting rod 12 to produce a transverse reciprocation of the grinding and follower wheels. The workpiece P and the pattern G are mounted between a common headstock 58 and centres 55, 59 adjustably secured to a table 48 reciprocated by a belt-driven rack and pinion. To enable a preliminary adjustment of the arms 1A, 1B to be effected, each screw 36A engages a nut 43A pivotally connected to an arm and is provided with a hand wheel 44A. The work piece and pattern may be rotated continuously or be indexed according to their shape. The follower wheel may be made from a material similar to that which serves as a binder for the abrasive of the grinding wheel. Fig. 3 shows a modification in which the follower wheel consists of a spool of tape which is gradually unwound by a ratchet-operated friction drive comprising two rollers 114, 115 one of which has a rubber-covered surface. The ratchet is operated in synchronism with the trueing device for the grinding wheel. A spring-loaded shoe 107 ensures that the tape remains tightly coiled. The tape may be magnetic and have a curved transverse profile to correspond with that of the grinding wheel.