GB324751A - Improvements relating to lathes and like machine tools - Google Patents

Abstract

324,751. Hopkinson, R. A., Metcalfe, T., and Hopkinsons, Ltd. Nov. 30, 1928. Chucks; indexing. -In a chuck of the kind in which the jaws are indexable about an axis perpendicular to the chuck axis in order to present different faces of the work for machining in a lathe &c., the means for rotating and locking the jaws are in part co-axial within the lathe spindle and are operated whilst the chuck is rotating. The chuck comprises two jaws a, b, the jaw a carrying a stem d rotatably mounted on the chuck c. A notched index plate e is attached to the stem d and is normally engaged by a spring plunger i. A toothed quadrant g is rotatable on the stem and is connected by gearing k .. p to a shaft q coaxial within the lathe spindle r and provided with a quick pitch thread s engaged by a nut t splined within the spindle. In operation, to index the work, the nut is moved axially by a lever v, causing the shaft q to be rotated relatively to the spindle and rotating the quadrant g. A face cam h on the quadrant first depresses the plunger i to release the index plate e and a spring pawl j on the quadrant then rotates the jaw by means of a ratchet f secured to the spindle d. On the return of the quadrant a spring pawl w, Fig. 3, prevents reverse rotation of the jaw until the plunger i engages the plate e. The opposing jaw b is rotatably mounted in a block x pressed inwards against a spring z to engage the work by a radial screw y. The amount of rotation imparted to the work may be varied by varying the pitch of the threads s or the traverse of the nut t and the jaws may be changed readily to suit the work.