GB860927A - Pneumatic chuck - Google Patents

Abstract

860,927. Chucks. ERICKSON TOOL CO. June 12, 1959, No. 20220/59. Class 83 (3). In a pneumatic chuck, the collet is operated by a sliding-sleeve actuated by levers rocked by a piston, the mechanical advantage of the levers increasing to a maximum at the final clamping-position. The chuck comprises a plate 2, Fig. 1, and a cylinder (i secured together by screws, and an adaptor 20 rotatably supported in plate 2 by a bearing 3 and in a piston 11 by a bearing 14. The adaptor 20 may be connected to a machine-spindle at either end, carries a coaxial slidable sleeve 30 which, when moved by the levers 32, actuates a collet in the adaptor 20. In operation air is supplied through a port 10 and moves the piston 11, seal 12 and a ring 23, to the left, thus moving the levers 32 from the solid-line-position, Fig. 4, to the dotted-line-position. Since the adaptor 20 is fixed axially, the ends 33 of the levers 32 move the sleeve 30 to the right, thus operating the collet in the gripping-direction. The moment-arm 52 will remain constant, but the arm 53 will decrease and the mechanical advantage of the lever will be greatest when the work is finally gripped by the collet. The levers are pivoted about pins 37 in slots 41 in a retaining-ring 40 and adaptor 20, and the pins are axially-movable in the slots. To release the collet, the air is vented through the port 10, and springs 48 move the piston to the right and springs 47 return the levers to their initial position. The mechanism is lubricated and cooled by an oil-air mixture, fed through a port 61, and the chuck-body is held stationary by a rod screwed into the hole 16. In a modification, the sleeve 30 is replaced by a sleeve coaxial with, but external to, the adaptor, which is moved axially by the heels of the levers 32, and a collet is incorporated with the sleeve and adaptor. The springs 47 are replaced by springs which urge the sleeve to the right directly. In a further modification, the bearings are dispensed with, and the chuck body is secured to and rotated with the adaptor.