Patent GB-516718-A (GB)
Title: Improvements in mechanisms for shaping and trueing the operative surface of grinding wheels used for form-grinding
IPC: B24B53/08
Filed: 1938-04-05
Abstract: 516,718. Trueing grinding-wheels. COVENTRY GAUGE & TOOL CO., Ltd., HARLEY, S. J., and OLAH, G. April 5, 1938, No. 10363. [Class 60] A frame b mounted to oscillate in bearings c in a fixed housing a supports a carrier d for the diamond d' adapted to rock vertically about pivots c<1> in the frame b. Eccentrically mounted in the frame b is a rotatable shaft f carrying circular cams i<1>, j<1>, (the projection i<6>, j<6>, are optional) adapted to co-operate respectively with rollers k, l, Fig. 5, adjustably secured in rings k<2>, l<3> themselves angularly adjustable in the housing a, and a cam g engaging an intermediate member h housing a pin h<2> adapted to contact with a pin d<1> in the diamond carrier d, the member n being urged towards the carrier d by a spring n<6>. At the' end of the diamond-carrier remote from the diamond, a spherical roller d<2> thereon is adapted to engage master-pieces m constituting rectilinear cams for a pantograph control of the diamond. When the spherical roller d<2> engages the master-pieces m, either the cam g leaves the upper surface h<1> of the intermediate member h, or the pin h<2> separates from the pin d<1> in the carrier d, the cam then playing no part in the control. To oscillate the frame b a ring having internal and external teeth n<1>, n' is oscillated in the housing a, a hand or power driven rack n', or a lead screw or cam, being operatively connected with the teeth n<7>, while the inner teeth n' engage a pinion n<8> carried by the frame b and meshing with a pinion n<9> on the cam shaft f. A restraint is placed upon the rotation of the pinion n<8> by a spring-pressed steel band so that when the cam i or j is not contacting with its roller k or l, the pinion does not rotate, but the entity consisting of'the frame b, pinions n<8>, n<9>, and cam shaft f is displaced angularly by the movement of the ring n'. When, however, this movement of the frame b has brought the cam i or j into contact with the roller k or l respectively, the movement of the frame is checked and continuance of the force applied by the continued movement of the ring n<1> overcomes the restraint applied to the pinion n', which thereafter rotates and turns the cam shaft f, the cams on which then control the motions of the carrier d, except in so far as the master-pieces m may free the cam g. Thus, in cutting a profile I ... VII, Fig. 12, for a screw thread a start is made while the cam shaft f is rotating, but while the spherical roller d<2> on the diamond carrier d is opposite one of the master pieces m, and this master-piece m determines the rectilinear motion during the cutting of the portion I ... II. At the point II, the spherical roller runs off the master-piece m and the cam g functions, co-operating with the supplementary cam i<6> or j<6> on the circular cam i or j, to cut the part II ... III. The circular part of the cam operates during the cutting of the portion III ... IV. To form the crest portion, only the angular motion of the frame b is required, and this is effected while the cam shaft f is being moved across the space between the rollers k, l. When the cam j or i. contacts with the roller l or k, dependent upon the direction of motion of the ring n', the parts V ...VI and VI ... VII are cut while the cams operate as for the parts III ... IV and II ... III. The carrier may he held stationary if it is desired to use a spherical diamond for,cutting a spherical groove. The apparatus is adjustable for different forms of curves. Slip gauges may be used to vary the angular settings of the cams i, j and the setting of the contact pin h<2> in the intermediate member h. The rollers k, l are adjustable along their supporting- brackets k<1>, l<1> on the angularly adjustable rings k<2>, l<2>, and threaded adjusting- means, such as m<11>, m<21> are provided for setting the master-pieces m. Specifications 228,445, [Class 60], and 398,841 are referred to.