GB344856A - Improvements in or relating to fluid pressure operating means for lathes, grinding, shaping and like machine tools - Google Patents

Abstract

344,856. Grinding. DRUMMOND, A., Ryde's Hill, Guildford, Surrey. Dec. 10, 1929, Nos. 37915/29 and 22603/30. [Class 60.] Driving and feed devices.-In a machine tool such as a grinding-machine or the like, the tool is moved by hydraulic pressure under the control of mechanical means such as a cam and is brought to rest at a predetermined position independently of the distance of travel of the mechanical means. In a lathe embodiment, the work A is turned by a tool C mounted in a longitudinally adjustable holder C<1> carried by a block C<2> which is adjustable on the cross slide C<3> of the longitudinal slide M. A piston rod D<2> integral with the slide M moves in a cylinder D carried by the cross slide and provided with a roller D<4> coacting with a feed cam F. In operation a starting handle H is moved to the dotted position, Fig. 4, and locked therein by a pawl H<1>. This opens a control valve for admitting fluid to the cylinder D and thus moves the tool quickly up to the work until the roller D<4> engages the feed cam. The feed cam is then rotated and a slow cutting feed is thus effected until a projection D5 on the cylinder engages a corresponding projection D<6> and brings the cross slide to rest. The cam F is mounted on a shaft F<2> driven through a belt F<4> and pinion F<5> from a rack on the piston F<10> of a stationary hydraulic cylinder F<11>. When the starting handle is operated, oil is admitted to this cylinder to start the rotation of the cam F. When the required depth feed has been effected, the tool is fed longitudinally by means of a cylinder M<1> bolted to the slide M, the piston M<3> being secured by nuts M<4>, M<5> to a fixed bracket M<6>. A casting N integral with the cylinder M carries a roller N<3> mounted on a spindle passing through a slot in the piston rod and the rod also carries a fixed roller M' supporting a wedge cam O. When the starting valve is operated, fluid is admitted to the cylinder M<1> but the longitudinal feed cannot operate until the in-feed is completed. At this point the rod F<9> engages a plunger P thus admitting fluid through an adjustable valve P<1> to a cylinder R which acts through a gear train R<5> to shift a slide R<10> carrying the cam O. The rearward movement of the cylinder M is limited by the nuts M<4> and the forward movement by a flange M<8> engaging a collar M<10> on the piston. After completion of the longitudinal feed the cam O continues its movement until the lower end of the slide R<10> trips the pawl H<1> to reverse the control valve and return the parts to normal position. The abutment D<5> or stop D<6> may be adjustable to permit variation in the length of the slow feed movement, and to vary the finishing position of the longitudinal movement the bracket M<6> is adjustable along the bed. The nuts M<4> may also be adjusted on the piston rod to vary the longitudinal travel. The shafts F<2>, R<7> may be extended and utilized for controlling any convenient number of cams. In a modification, instead of limiting the movement of the tool by separate fixed stops the cam may be designed to permit the desired movement and then to continue its own movement without affecting the tool position. Thus the cam O may be formed with a dwell and when the roller N<3> reaches this part of the cam it will remain stationary during any further movement of the cam.