GB512353A - Improvements in or relating to chucks for parts with screw threads - Google Patents

Abstract

512,353. Chucks and sockets. FORKARDT, R. June 27, 1938, No. 19043. Convention date, June 28, 1937. [Class 83 (iii)] A chuck for holding screw-threaded workpieces has jaws with threaded gripping portions which are moved radially for engaging the screw thread and then axially for bringing the work-piece against a flat or conical end surface on the chuck body. In one form the jaws 3, Fig. 2, are capable of sliding radially, in slots in the body 1 and are attached by pins 6 to a sleeve 5 normally pressed outwards by a spring 11 within limits determined by a screw 9 engaging an annular recess 5<1> therein. A central plunger 2 guided within a bore in the body 1 is actuated by a draw-spindle 13 and has bevelled surfaces 2' engaging the jaws. When the chuck is unloaded the plunger 2 and jaws 3 are towards'the right and a spring 12 maintains the jaws collapsed against the surfaces 2' so that an internally screwed article 14 may be placed over the jaws. The draw spindle then moves the plunger 2 to the left and the spring 11 prevents the jaws from moving axially so that they ride along the surfaces 2' until they have been expanded into full engagement with the threads on the work. Further movement of the draw-spindle causes the jaws and plunger 2 to press the end of the work firmly against an end surface 4 on the chuck body whereupon the gripping of the work is complete. In a modified form for gripping externally screwed work a sleeve 2a, Fig. 4, is attached to the draw-spindle 13 and carries bevel-closing slides 2b engaging the jaws 3. A sleeve 5 is pressed by a spring 11 'to engage the jaws through an inclined shoulder 5<1> and force the jaws both axially forwards and' radially outwards against the slides 2b. Forward motion of the jaws is limited by lateral shoulders thereon engaging an annular recess 1<1> in the body 1 and the spring 11 abuts through a ring 7a and pins 7b on a ring 7c. In operation, rearward motion of the draw-spindle moves the slides 2b rearwardly and closes the jaws radially on the threads of the work 14, after which further axial movement of the drawspindle moves the jaws against the spring 11 to press the work against an end surface 4 of the body 1. In another form for gripping externally screwed work a bevelled cap 2, Fig. 6, is attached by a transverse pin 2c to the drawspindle 13 and the jaws 3 are guided radially on a flange 5 pressed forwardly by a spring 11. In the unloaded position springs 12 expand the jaws against the cap 2 and after insertion of the work 14 rearward motion of the draw-spindle moves the cap rearwardly to close the jaws on the work, after which further motion of the draw-spindle moves the jaws against the spring 11 to press the work against the body at 4.