GB1193078A - Work Supports for Machine Tools. - Google Patents

Abstract

1,193,078. Grinding; tailstocks. A. A. JONES & SHIPMAN Ltd., and J. HOULDSWORTH. 22 Sept., 1967 [23 Sept., 1966], No. 42435/66. Headings B3D and B3T. A work support (e.g. a tailstock for a grinding machine) comprises a centre 3 carried by a ram 2, a drive motor 14 connected through yielding means to the ram, means, such as switches, for limiting axial movement of the ram and means for indicating correct or incorrect engagement of the workpiece. To move the centre 3 to the IN position, a tubular housing 17 is moved to the right, Fig. 1, by a nut 11 driven by the motor 14, the end of the housing being provided with a fixed plate 31 and a yieldable sleeve 30 for operating one end 8 of a lever 4, Fig. 3, which is mounted on a shaft 5 for pivotal movement therewith. Spring-pressure on the sleeve 30 may be adjusted by a screwthreaded spindle 23 which is rotated by a knob 24 within a nut 26. The shaft 5 carries lugs (35, 36), Fig. 5 (not shown) for contacting switches (LS1, LS2) which serve to stop the motor 14 when the ram reaches the set limits of travel (so long as the movement remains unobstructed). When the centre 3 engages a workpiece, further movement of ram 2 is stopped but movement of the housing 17 continues so as to apply the spring load. A switch (LS3), Fig. 4 not shown) carried by the shaft 5 contacts a screw (39) to stop the motor 14 when the ram 2 has been loaded by the spring 29. A switch (LS4) carried by the shaft is arranged to contact a screw (40) only when the ram is forced back in the OUT direction, the signal from this switch being used to relieve grinding pressure. A switch LS5 is also carried by the shaft 5 and is set to contact an adjustable stop 47 at a distance corresponding to the travel required for the centre to enter the workpiece; unless the switch LS5 is actuated, other signals become inoperative so that the machine cannot be operated in the presence of incorrect engagement of the centre as in Fig. 6 (not shown). This safety device may be modified, Figs. 8-11 (not shown) for use with varying lengths of workpieces. In this case a sensing arm (60) is moved by the end of the workpiece when the centre has been successfully engaged, the sensing arm moving a catch (61) which makes contact with a switch (LS5) and allows the sensing arm to be pulled clear of the workpiece by freeing spring-levers (53). The various switches may operate indicator lamps. The drive may be hydraulic instead of electric and the switches replaced by valves.