Patent GB-961463-A (GB)
Title: Improvements in chucks
IPC: B23B31/16
Filed: 1962-03-08
Abstract: 961,463. Chucks. A. KOSTYRKA. March 8, 1962 [March 10, 1961], No. 9041/62. Heading B3B. A chuck comprises a base 10 supporting a head 13 which has piston-and-cylinder units 63, 64 for moving the jaws 55, and hydraulic means 40, 41 responsive to rearward movements of the head 13 towards the base 10, for causing the units 63, 64 to move the jaws, whereby a workpiece engaging and moving the rearwardly may be gripped by the jaws. A skirt 14 on the head surrounds the base, which has a key 18 engaging a keyway in the skirt. The hydraulic means 40, 41 comprise three pistons 41 in axial cylinders 40 in the head which are connected by passages 60 to an annular chamber 61. Connected with the chamber 61 are the racial cylinders 63, forming a closed hydraulic circuit pressurized, to close the jaws, by movement of the cylinders 40 over the pistons 41. These have rods 42 bearing against pads 44 backed by springs 50 which compress at the appropriate hydraulic pressure. A centre 22 is moved rearwardly by the workpiece. against the influence of springs 30, until it engages a collar 25, when further pressure by the work causes rearward movement of the head. This is limited by stop-sleeves 80, Fig. 6, carrying rearwardly-projecting, spring-loaded indicating pins 83, the forward ends 85 of which are advanced until they are flush with the front face of the head when the stop-sleeves engage the base 10. Guide-pins 72 for the radial pistons 64 support return springs 73 and stop-sleeves 75. Pins 66 passing through slots 65 in the head 13 connect the pistons 64 to jaw-carriers 54. Adjustment of the jaws, e.g. to clamp irregular work surfaces, is by auxiliary pistons 93, Fig. 4, adjusted by screws 95 in radial cylinders 92 connected to the annular passage 61. In a modification, Fig. 8, a single, axial pressurizing piston 194 is provided, the axial position of which may be adjusted by a stop-screw 226 engaging screw threads in the pad 234. This is backed by springs preloaded by a screw 242 in accordance with a scale on a collar 242. The cylinder 192 for piston 194 is secured to the head 138 and has a flange 190 limiting forward movement of the head relatively to the base 130. The jaw-pistons 154 are fixed to forward projections 148 from the head 138 and engage cylinders 180 in the jaw-carriers 158, which are movable radially, against the influence of springs 184. The cylinders 192, 180 are interconnected by passages 176 and bases 178 passing through the pistons 154. At least one adjustable stop 202, carrying a return spring 210 for the head 138, has an indicating pin 204, the end of which is flush with the forward face of the head when the rear face 208 has moved back against a shoulder 206 on the stop. In a further modification, Fig. 10, the axial piston 334 is attached to a sleeve 330 with a flange 328 bearing on the control springs 306. These are compressed between a flange 308 in the base 302 and a collar 310 which is adjustable by a screw 318. In yet another modification, Figs. 11 and 12, there is provided a plurality of axial pressurizing pistons 446 and fixed radial pistons 412 for movable jaw-cylinders, as in Fig. 8. A central, rough-adjustment piston-and-screw 472, 476 are provided in the head 404, through which passes an adjustable stop 432 having an abutment surface 434 and a return spring 440. Springs may be located between the piston 472 and screw 476.