Patent GB-417142-A (GB)
Title: Means for measuring and controlling the operation of grinding or abrading machines
IPC: B24B49/18
Filed: 1933-05-31
Abstract: 417,142. Grinding. WOTAN-UND ZIMMERMANNWERKE AKT. - GES., 1, Harkortstrasse, D³sseldorf, Germany. May 31, 1933, No. 15721. Convention date, May 31, 1932. Addition to 306,973, [Class 60]. [Class 60.] Means for measuring and controlling the operation of a grinding-machine comprises means for correcting for the reduction of the diameter of the grinding-wheel due to wear and trueing, the correction being made in two steps. The means comprises an indicator scale 5 over which a pointer arm 4 is moved by the end 9 of a rod 6 friction tight at 7 in a cross feed slide carrying the grinding-wheel 2. The other end of the rod, during an extended traverse of the grinding-wheel out of the work 1 for trueing the wheel by a diamond 15, encounters an abutment 14 mounted in fixed relation to the diamond point, the rod thereby being slid lengthways to the extent of trueing feed of the slide, and moving the pointer arm back over the scale, so that an additional final feed of the grinding-wheel is required to bring the work to size. The grinding-wheel is then withdrawn from the finished work and makes a further extended traverse, during which the end of the rod 6 encounters a second abutment 13 set to move the rod to an extent corresponding to the average or estimated reduction of diameter of the grinding-wheel during rough grinding prior to trueing for the finish grinding ; the pointer arm moves back a corresponding amount. An internal grinding machine embodying the above arrangement is shown in Fig. 3, and details of the measuring device in Figs. 5, 7 and 8. The machine comprises a bed 16 on which slides a hydraulically traversed table 17 carrying a cross feed slide 33 on which is mounted the grinding wheel 24, the work 21 being mounted in and driven by a head 19. The slide 33 may be fed by a hand-wheel 25 or by a pawl 26 operated through gearing and a shaft 29 from a piston mounted in a casing 30, to which fluid is delivered through pipes 31, 32 from both sides of the piston operating the table 17. The measuring-device or indicator consists of a dial 38 adjustably mounted by a nut 36 on a bed 34 in which the slide 33 moves, and within the indicator casing 37 is a stem 48 moving the pointer and carrying an electric contact 49 adapted to complete a circuit with an adjustable contact 50. The stem 48 is actuated through a lever 47 by a rod 39 guided with friction in a bearing 40 on the slide 33, and against the end of the rod is held, by a spring 43, an adjustable screw 451 in a lever 45 pivoted on a bolt 44 on the bed 34. The bed 16 carries an adjustable abutment 46 in such position that during normal traverse of the table 17, the lower end of the lever 45 does not reach the abutment, but when the table makes an extended stroke for trueing the grinding-wheel, the lever encounters the abutment, the operative face of which is set in fixed relation to the point of the trueing diamond 54 (not shown), and moves the rod 39 back an amount corresponding to the feed of the grinding-wheel during trueing ; the trueing stroke of the table is brought about by closing of the contacts 49, 50 and causes the table reversing lever 51 to move to miss a stop 52, and to be moved by a stop 53. After trueing, the normal stroke of the table is resumed until the contacts 49, 50 are again closed, upon the work reaching finished size, when the table makes a more extended stroke ; fluid is simultaneously fed to a pipe 54 and lowers the abutment 46, so that the lever 45 does not strike it, but strikes a second adjustable abutment 57, set by a screw to move the rod 39 an amount corresponding to the average reduction of the grinding- wheel due to wear during rough grinding ; this sets back the pointer of the indicator for starting grinding of a new work piece.