| 摘要 |
1,229,479. Lathes. KEARNEY & TRECKER CORP. 11 Sept., 1968 [15 Sept., 1967], No. 43199/68. Headings B3B and B3T. In a machine tool such as a lathe having a headstock 10 incorporating a rotatable workholding spindle 11, first drive means is provided for rotating the spindle at selected speeds during a normal machining operation and second drive means operable when the first drive means is disconnected is provided to rotate the spindle to position it in a predetermined angular position. The first drive comprises a selectable gear transmission 12 driven from a motor 18 on the headstock 10 the output of the transmission 12 being transmitted to the spindle 11 via a changegear cluster 13 which is selectively engageable with gears 14 and 15 on the spindle 11. The output from the motor 18 is connected to the transmission 12 by way of selectively operable hydraulic clutches which permit driving, reversing and creep movements of the spindle. The second drive means comprises a reduction bevel gear unit 58 driven from a servo-controlled hydraulic motor 50 independently supported on the headstock, a driving connection 65 between the unit 58 and the spindle 11 being selectively effected by way of axially extending and engageable toothed members 66 and 67 mounted on the drive sleeve 59 of the unit 58 and the spindle end respectively. The toothed member 66 is splined to the sleeve 59 and is axially movable thereon by means of an hydraulic piston and cylinder unit 83, 84 which actuates a yoke 75 connected to the member 66 to move it selectively into and out of engagement with its co-operating member 67. In order to accurately position the spindle 11, information supplied to a data input means which produces signals is conveyed to a control unit which actuates the motor 50 which drives the spindle through the gear unit 58 in the ratio 180 : 1. The motor simultaneously drives a resolver 110 which rotates in the same ratio with respect to the spindle and operates to provide a feed-back signal to indicate the actual position of the spindle. In order to overcome the respective signals produced by the resolver and to identify that signal denoting exact required angular position of the spindle a switch 122 mounted on the fork 75 is actuated by a cam dog 121 secured to the spindle and which stops the motor 50. The operation of the apparatus may be effected manually or by magnetic or punched tape and whereby the spindle may be indexed to a plurality of predetermined angular positions. A control system and electrical circuit are described with reference to Figs. 4 and 5 (not shown). |
