Patent GB-1485434-A (GB)
Title: Infeed device for the grinding tools of grinding machines
IPC: B24B49/18
Filed: 1974-09-12
Abstract: 1485434 Truing grinding wheels REISHAUER AG 12 Sept 1974 [17 Sept 1973] 39899/74 Heading B3D In a grinding machine, for example, a cylindrical grinder or thread grinding machine means is provided to control the infeed defined by the relative movement between the workpiece and the grinding wheel in which the positional relationship between the wheel and workpiece is maintained by compensating for the reduction in diameter of the grinding wheel 21 as a result of truing and in relation to the wear of the truing tool. In the embodiments described the machine is provided with a longitudinal slide 2 which supports a grinding carriage 3 movable by a feed screw 12 transversely to the axis of the workpiece 7. The carriage 3 is provided with an arcuate slide 14 which supports a saddle 15 which in turn supports a truing slide 18 and the grinding wheel and motor assembly 16, 17, the arcuate slide 14 permitting accurate angular orientation of the grinding wheel 21 with respect to the workpiece for example the angular helix of the thread on a workpiece. The truing slide 18 is adapted to carry one or more truing tools and holders 20, 42 and which are displaceable parallel to the axis of the grinding wheel by a screw 43. The saddle 15 displaceable transversely to the axis H of the workpiece 7 and the displacement of the saddle for truing compensation for the grinding wheel takes place only with the simultaneous displacement of the truing slide 18 by rotation of the screw and handle 24, 23. The screw 24 is provided with a L.H. thread and engages with captive nut N of the truing slide 18, the screw being axially supported by a thrust bearing 25 which is longitudinally slidable in the saddle 15 in order to perform a correction displacement of the truing slide. The screw spindle 24 is also provided with a gear 26 which meshes with a spindle nut 27 of a further screw spindle 28 which is axially retained in the arcuate slide 14 and is prevented from rotation by a lug with a square hole in the saddle 15. In order to obtain a workpiece 7 whose diameter "d" is accurate as a result of the feed movement A of the grinding wheel, the feed movement B of the truing slide 18 is made larger by a predetermined amount C (referred to as the correction displacement). The correction displacement of the truing slide 18 is effected by way of an interchangeable slide member 30 located in the saddle 15 so as to be slidable transversely with respect to the direction of movement of the saddle but fixed in the direction of movement of the saddle, the slide 30 having a preformed slot P whose shape is determined by preconceived data. A slider pin 21 which extends from the thrust bearing 25 engages in the slot P. In this arrangement the position of the slider 30 with respect to the saddle 15 is determined by the instantaneous position of the saddle 15 on the arcuate slide 14 every movement of the slide 30 being in accordance with the shape of the slot P. The transverse displacement of the slider member 30 is controlled by a template 32 mounted on the truing slide 18 along which a tracer 33 fixed to the slide 30 moves. The shape of the slot P and template have respectively complementary curved and straight profiles. The interrelation of these constructional features is such that the rotation of the hand wheel 23 causes a differential motion between the saddle 15, truing slide 18 and slider member 30 to provide the compensated infeed of the grinding wheel to maintain the true dimensions of the workpiece having compensated for wheel truing and truing tool wear.