Francis J Cook

US Patent:

41063759, Aug 15, 1978

Filed:

Apr 18, 1975

Appl. No.:

5/569543

Inventors:

Felix J. Gurdak - Winsted CT
Francis W. Cook - Newington CT

Assignee:

Litton Industrial Products, Inc. - New Britain CT

International Classification:

B23B 332

US Classification:

82 21B

Abstract:

A high-production, precision machine tool has means for varying the feed rate of the tool during the actual machining of each workpiece. The means comprise a plurality of program cams disposed on the camshaft of the machine tool for selecting the appropriate feed rate at the desired time during the machining operation. The camshaft is rotated by a permanent magnet D. C. motor, and as the camshaft rotates, the program cams, in turn, trip a plurality of switches to gate one of several predetermined voltage signals representative of the desired motor speeds to a comparator which compares the gated signal with the output of a tachometer measuring the actual motor speed. The difference, a voltage signal representative of the correction to be made to the motor, is applied to a silicon controlled rectifier firing circuit which selectively fires an SCR network, generating a shaped pulse to provide a controlled voltage input to the motor, thereby selectively controlling its speed.