Patent GB-454246-A (GB)
Title: Improvements in and relating to chucks or drivers for wheel lathes or the like
IPC: B23B5/34
Filed: 1935-03-26
Abstract: 454,246. Chucks; carriers for wheel lathes &c. HEGENSCHEIDT AKT.-GES., W., Ratibor, Germany. March 26, 1935, No. 9438. Convention date, March 29, 1934. [Class 83 (iii)] In a chuck or carrier for wheel lathes, &c., having means for automatically equalizing the pressure of the jaws, a number of jaws are mounted on the pivots of a regular closed polygon linkage so as to be readily movable on the chuck body, while all the pivots except one can move relatively to the jaws in directions at right angles to the radial movements of the jaws. In one form the body a has radial guides for the jaws 1 ... 4 and the pivots 5 ... 8 of the links 9 ... 12 bear on the jaws through shoes 30 and 17 .. 19. The shoe 30 is guided radially on the body but the shoes 17 .. 19 are transversely movable and act on the jaws through needle bearings 27. The jaws are moved radially simultaneously by wedges 23 acting between the shoes and jaws and carried by links 39 from a ring 38 rotatable on the body a. Relative rotation between the ring and body is produced by a ring 39<1> provided with friction surfaces engaging the ring 38 and carrying a tooth 411 adapted to engage a fixed stop when the body is rotated. The jaws 1, 2 and 4 are drawn by springs 33 against stops 36 in the contracted position, but no stop is provided for the jaw 3 so that its spring 37 may contract the linkage fully. In a modification the jaws consist of levers 43, Fig. 3, mounted on pivots 44 carried by shoes 45 supported through needle bearings 22 from the shoes 19 on the linkage pivots 8, clamping being effected by rocking the levers 43 by means of wedges 26 acting between a fixed ring 47 on the body a and shoes 48 engaging the ends of the levers through pins 49. The wedges are operated simultaneously by friction rings 38, 39<1> similar to those of Fig. 1. In a further modification one or more of the links 9, Fig. 1, is divided and pivoted at the middle to act as a toggle on the pivots 5, 6, the toggle being straightened by a wedge moved in a similar manner to the wedges 23. In a further modification the toggles 57, Fig. 5, are formed double and are straightened by right and left handed screws 58 operated simultaneously by gears 61 thereon engaging a gear ring concentric with the body a. In another modification the pivots 7, 8, Fig. 5, are joined by right and left-handed screws engaging a common nut, all the nuts being rotated simultaneously to expand the linkage by means of worm wheels thereon and worms which are driven through cardan shafts by a bevel gear concentric with the body a. In a modification of the form shown in Fig. 1, the jaws may be carried by levers swinging in the plane of rotation of the chuck and pivoted on the body a, instead of being mounted in radial guides. The constructions described above may be used to apply the initial gripping force only, the final grip being applied by the resistance to rotation of the work in known manner. For this purpose, the jaws may slide transversely on inclined guides on supports guided radially in the body a, springs being provided to draw the jaws normally into their contracted positions.