| 摘要 |
903,113. Machine-tool details. CROSS CO. Jan. 9, 1961 [Jan. 11, 1960], No. 907/61. Class 83 (3). An indexable table assembly comprises a plurality of stops 82 on the table, drive means to move the table to bring a stop against a locating pin 84, and switch means 96 operated by the engagement of the pin and stop to initiate an operation of the machine-tool. The outer edges of the table are supported by a P.T.F.E. bearing and the supporting-shaft runs in an oil bath. The table is rotated through gears 72, 46 by a reversible electric motor but may be rotated by a pawl-and-ratchet drive, a Geneva mechanism, a cam, or a fluid-pressure motor. During indexing, a stop 82 depresses the pin 84 causing an arm 100 of the switch 96 to be depressed and reverse the motor. The stop meanwhile rides over the pin as the table starts to reverse to back the stop against the pin. An air passage in the pin is closed when the stop and pin are in contact, causing a plunger 108 to rise and actuate the switch 96 to a further position. The motor is then stopped, the table being locked by the non-reversible worm drive, and a working operation of the machine-tool is initiated. |
