Patent GB-789728-A (GB)
Title: Improvements in or relating to a truing device for a grinding machine
IPC: B24B53/075
Filed: 1954-11-23
Abstract: 789,728. Trueing grinding wheels. MAAG GEAR-WHEEL and MACHINE CO., Ltd., and WILDHABER, E. Nov. 23, 1954 [Nov. 27, 1953], No. 18642/56. Divided out of 789,727. Class 60. A trueing tool for producing a radiused profile 204 at the periphery of a grinding wheel W<SP>1</SP> is swung across the working face of the wheel by mounting it in a support which is oscillated about an axis 210, Figs. 1 and 2, inclined to the plane side face of the wheel and to an axial plane extending through a mean point of the path of the tool, and at the same time is moved parallel to this axis in the same direction as the tool swings from one end of its path to the other at a rate which is a greater ratio to the velocity of the swinging movement adjacent the ends of the swing than in the middle portion of the swing. The effect of this modified movement of the tool is to produce a profile the radius of which, as seen in Fig. 1, decreases on one side of the mean point 207 of the active grinding profile to the periphery of the wheel and increases on the other side of the mean point ; the axis 210 intersects the surface normal at the mean point 207 at the centre of curvature 215 of the profile. In the adaptation shown in Fig. 3, the holder 226 of a trueing diamond 201 is mounted for adjustment to and from the wheel W<SP>1</SP> along the axis 230 in a carrier 231 which is journalled in spaced bearings 241, 242 in a housing 240 so that it can be oscillated about the axis 210 ; the holder 226 is fixed in its adjusted position in the carrier 231 by a screw 233 acting through an elastic disc 237 and pin 235, and a flexible seal 262 is fitted around the housing 240. The carrier 231 is oscillated about the axis 210 either by hand or by an hydraulic piston operating a rack meshing with peripheral teeth 254 on the carrier. Movement of the carrier along the axis is effected by means of a follower 220 which is carried by a sleeve 245 fixed to the carrier and during the oscillation of the latter is urged by a coil spring 251 into co-operation with a face cam 252 surrounding the sleeve ; the cam is so shaped that the carrier, during each oscillating stroke, is moved axially at a variable rate which is zero when the diamond reaches the mean point 207 of the profile. The cam may be either fixed about the axis 210, or adjustable around the same to accommodate compensation-forwear movements of the trueing slide towards the wheel axis by means of a ring 256 surrounding the cam and having internal teeth meshing with teeth on the periphery of the cam. The cam may be provided with several different operative faces, any one of which may be rendered effective by adjusting the position of the cam. In the modification shown in Fig. 7, two dressers 226 for trueing the oposite faces of a wheel are each mounted for movement along the axis 275 to and from the wheel in an oscillating carrier 231 provided with a cam follower 220 cooperating with a face cam 252. The housing 240 of each carrier is mounted for adjustment parallel to the axis 275 on a circular slide 277 which is adjustable about a pin 280 on a main slide 281 movable for adjusting the dressers radially of the wheel. The timing of each cam is changed as the diameter of the wheel becomes reduced by trueing by connecting a link 285 of adjustable length between a ball joint 284 on the cam and a ball joint 282 on a slide 283 adjustable parallel to the main slide 281. The links 285 are initially set at the desired inclination by adjusting the slide 283 and fixing it in position ; subsequent adjustments of the slide 281 cause corresponding adjustments in the timing of the cams. In the further modification shown in Fig. 8, the two oscillating carriers 231 are set at fixed inclinations in their housings on slides 287 movable parallel to the wheel axis on a common slide 286 which is movable at right angles to the wheel axis. Oscillation of the carriers is effected by hydraulic cylinders 288 on the slide 286 having pistons 289 acting through a pivoted lever 290 upon a ring 292 engaging a sleeve 293 which has screwthreaded engagement with the ends of racks 294 meshing with teeth on the carriers. The pivotal mounting 295 of the lever 290 is adjustable vertically in order to change the angle of oscillation of the carriers. The screwthreaded engagement of the sleeve 293 with the two racks is of opposite hand so that by turning the sleeve with the carriers locked against oscillation the slides 287 can be adjusted equally in opposite directions and by turning it with the slides 287 locked in position the mean positions of swing of the two carriers may be simultaneously adjusted. The cams may be adjusted from the feed screw 302 for altering the position of the slide 286 through mechanism including change gears and a worm wheel having splined connections with two shafts which are respectively mounted on the two slides 287 and carry gears for rotating the cams. A diamond for trueing the edge of the wheel may be mounted to move with the ring 292.