GB746404A - Improvements in or relating to an arbor chuck - Google Patents

Abstract

746,404. Chucks and mandrels. WOODWORTH CO., N. A. Jan. 20, 1954 [Feb. 9, 1953], No. 1699/54. Class 83 (3). An expanding-mandrel or chuck-collet comprises a tubular body with rigid circumferentially-continuous ends 30, slots 26 intermediate the ends dividing the body into radially-flexible members 28 and one or more bosses 34 on each member 28, together defining work-engaging means. The mandrel shown in Fig. 1 is for gripping short bore in the work and, as the diameter of the bosses 34 is slightly greater than that of the bore, the mandrel must be forced into the bore, thus causing the members 28 to flex into a concave shape and the bosses 34 to engage the bore only at their outer edges so that the work is accurately centred at right angles to the mandrel axis. For ease in handling, knurled ridges 44 are provided and, for mounting between centres for checking the work, plugs 22 are fitted in the ends of the body. Two work-engaging surfaces of different radii may be provided on the bosses, with a relieved portion between them, and a flange forming an end stop on one of them. In an alternative form, the body has a mounting shank at one end and a centre plug at the other end; in this form, the bosses have threads for gripping a screwed bore and the body may be constricted, so that work can be screwed on the threads, by means such as a cable anchored at one end, wrapped round the body and connected to a tensioning lever. The collet of Fig. 7 has spaced gripping-surfaces or, as shown, splines 132 fitting into splines on the work 136 and the flexible members 28 have internal conesurfaces 102 so that they can be positively expanded by a rod 104 bearing against an adjusting screw 110. A driver 138 is provided and also an end stop, which may be a plain sleeve fitting closely on a part 96 of the body, or a sleeve 146 mounted on a flexible ring 150 and having ends 152, 154 tapered at right angles to each other so that the sleeve can rock to accommodate itself to a work-face which is not at right angles to the axis of the bore being chucked. In Fig. 8, the big-end of the collet body is secured to a cylinder 162, and fluid supplied through a pipe 176 moves the piston 168 to expand the collet, the piston being returned by springs 170. In Fig. 11, the collet is adapted for external gripping of twodiameter work 210 and is contracted by a screwed bevel-closing ring 220. Alternate surfaces 202, 204 on each boss are relieved at 206, 208 in staggered relation round the circumference of the collet so that each boss grips its corresponding diameter independently, and therefore the collet adapts itself to varying tolerances on the two diameters. End stops 226 are provided on each flexible member.