GB427064A - Improvements in and relating to trueing the grinding surface of the grinding wheels of screw thread grinding machines - Google Patents

Abstract

427,064. Grinding screw - threads. TURRETTINI, F., 8, Rue des Vieux Grenadiers, Geneva, Switzerland. May 24, 1934, No. 15511. [Class 60] [See also Group XXII] In a machine for grinding screwthreads, means is provided for trueing the grinding - wheel to the exact profile of the thread, comprising the formation of a cam under control of the diamond moved along a master thread, and subsequent use of the cam to control the movement of the diamond in contact with the grinding - wheel, whereby as the diamond wears, a new cam surface, corresponding to the altered shape of the diamond may be cut. The work-piece 3 on which the thread is required is carried and rotated on a table 1 slidable on a bed 2 past the grinding- wheel 4, which is mounted on a support 5 adjustable towards and from the work. The support 5 also carries a master 7 having thereon a thread 8 of the size to be ground, and on the table 1 is pivoted an arm 10 carrying the diamond 6 ; the table also carries a transversely movable slide 20 supporting a disc 13, on which the cam 33 is to be cut by means of a cutting-tool, for example a milling-cutter 14, rotated at the same speed as the work. As the table 1 moves along the bed, the diamond moves up the side of a thread profile of the master, and then down the other side, these movements causing corresponding movements of the slide 20 by means of a screw 19 driven in one direction or the other by reversible bevel-gearing 15 .. 17, controlled by solenoids 27, 28, in the circuits of which are, respectively, contacts 31, 30 engaged by a contact 32 on the arm 10. When the cam has been cut, the screw 19 is disconnected from the slide, the cutter 14 is replaced by a roller having the same diameter, and the contacts 30, 31 are approached to engage the contact 32 on the end of the lever 10. The diamond is then, by movement of the table 1, located opposite the wheel 4 and, with the table and the cam 33 moving at the speeds used for forming the cam, the grinding-wheel is trued ; the process is repeated when the diamond has changed its outline due to wear. The master may be set, as shown in dotted lines, for work of a diameter larger than that of the master ; as the thread on the master becomÚs worn by the diamond, the master may be turned on its support 36 to present a new portion to the diamond.