GB631690A - Improvements in or relating to engineers' work holding devices and like appliances - Google Patents

Abstract

631,690. Work-holders. WALFORD, H. A., ALL PRECISION ENGINEERING, Ltd., and HALE, L. E. April 22, 1947, No. 10777. [Class 61 (ii)] [Also in Group XXII] The work-holding arm of an engineer's or other work-holder is jointed to and angularly movable on a base-member and is clamped in any desired position by a hydraulic plunger acted on by liquid pressure. The work-holder, not shown, is screwed at 48 to the stem 43 of a ball 42 retained in a hemispherical recess 41 of an inverted cup-shaped socket member 40 by a clamping member 45 held in the member 40 by a ring 47. The arm 43 is vertically movable in a slot 44 in the member 40 which is freely turnable about a flange 38 on the base-member 10 securely fixed to a bench 12. The ball 42 is clamped by the upward movement of a plunger 35 slidably fitted in a motor cylinder 14 in the base-member, being actuated by the pressure created by movement to the left of a pump piston 28 in the cylinder 16 on liquid 37 such as thick oil which completely fills the cylinders 14 and 16 and the passageway 15. The piston 28 is operated by a cam 21 which engages the head 33 of a thrust screw 32 and is pivoted at 20 to brackets on the base-member and connected by links 24 and a lever 27 to a pedal rod. A cranked arm 50 and counterweight 51 may be used to balance the workholder. In a modification, the clampingmember 45 is provided with a coiled compression spring to make the release of the ball more certain and in place of the cam 21 the piston 28 is actuated by a thrust screw and coiled compression spring, the pressure being released by a lever which engages a shoulder on a thrust rod and compresses the latter spring.