Patent GB-909351-A (GB)
Title: Device for angularly positioning a rotatable member
IPC: B23Q5/20
Filed: 1958-12-29
Abstract: 909,351. Clutch control; stopping in predetermined positions; cams. NATIONAL ACME CO. Dec. 29, 1958 [Sept. 11, 1958], No. 41837/58. Classes 80 (2) and 80 (3). [Also in Group XXII] A shaft 29, such as a work spindle of a multispindle machine tool, is moved to and located in an invariable predetermined angular position by moving a cam follower 64, Figs. 2 and 8, axially against a cam surface 126 on the shaft, such movement causing the shaft to turn as the follower rides down one or other surface 132, 133 of the cam until the follower drops into a recess 137 at the low point and thereby locks the shaft in the corresponding angular position. To avoid possible initial detention of the follower 64 on the high point 130 of the cam 126, a second cam 127 with a staggered high point is provided, and the arrangement is such that before the follower 64 is moved leftwards, it is given an initial rightward movement by which, if necessary, it acts on the second cam 127 to turn the shaft, so that the high point 30 of the first cam is not aligned with the subsequent return leftward path of the follower 64. The follower is moved by fluid pressure means described below. In the multiple spindle chucking machine, Fig. 1, a spindle carrier 26 supporting six spindles (three, 28, 29, 30 having chucks 33, 34, 35 being shown) is indexible to six working positions relative to tool slides 37, 38, 39. The above described cam spindle locating control, is applied only to the spindle 29. Each spindle is driven through a clutch 53, Fig. 2, and has a brake 55 both controlled by a fork 57 which has also a neutral position. The clutch brake control 40 comprises a fixed cylinder 72, Fig. 6, containing a piston 100 connected to the cam follower 64 surrounded by a movable cylinder 77 connectible to the collar 57 of each spindle as it is indexed to the station having the device 40; the piston and movable cylinder each being movable to the three positions under the control of a pressure fluid distributer mechanism 60. The three operative positions of the cylinder 77 are obtained by having a spacer ring 82 attached to the cylinder 72, a floating piston 83 moving within the limits of a chamber 84 and inlet ports 81, 85 and 86 communicating through passageways 88, 89 and 90 with chambers 92, 93 and 94 respectively so that by continuously supplying fluid pressure to chamber 92 and selectively exhausting chamber 94 and supplying fluid pressure to chamber 93, the effective area of chambers 93 and 94 being greater than that of 92 causes the outer cylinder to assume the position shown, determined by the engagement of the floating piston 83 with the outer cylinder, to permit free rotation of the spindle. By exhausting chamber 93 and supplying pressure fluid to chamber 94 the outer cylinder is caused to move to the extreme right or driving position, and by exhausting both chambers 93 and 94 the outer cylinder is caused to move to the extreme left or braking position. The three operative positions of the piston 100 are obtained by means of a floating piston 103 forming chambers 107 and 108 which are supplied with pressure fluid through ports 140 and 111 respectively, a further chamber 106 being formed by the piston 100 and cylinder 72. Chamber 106 is continuously supplied with pressure fluid from the passage 88 and as shown chamber 108 is exhausted and chamber 107 is supplied with pressure fluid so that the effective area of chamber 107 being larger than that of chamber 106 causes the free piston 103 to abut cylinder shoulder 124 to obtain the neutral position. Chambers 107 and 108 are both exhausted to move the piston to the right or cam adjustment position and to move the piston to the left or spindle locating position pressure fluid is supplied to chamber 108 and exhausted from chamber 107. A control rod 120 limits the stroke of the piston through a switch 121.