Patent GB-889148-A (GB)
Title: A machine tool for automatic cycle programming
IPC: G05B19/04
Filed: 1959-03-31
Abstract: 889,148. Copy-milling. CINCINNATI MILLING MACHINE CO. March 31, 1959 [June 3, 1958], No. 10809/59. Class 83 (3). A machine tool comprises a stepping switch for connecting a series of function determining circuits to a source of potential to move a machine element and a trip dog on the element for causing stepping of the switch. A milling cutter 38 in an axially adjustable quill is driven by a motor mounted on a carriage 36 moved vertically by an hydraulic motor 48 driving a feed screw. The workpiece 39 is mounted on a table 33 moved through rack-and-pinion gearing by an hydraulic motor. The machine is programmed to cut three keyways 51, 52, 53, the sequence of movements being indicated in Figs. 12 and 13. Dogs 61 mounted in two slots 57, 58 in the table co-operate with four switches in a box 63 to control the movements of the table and a similar set control the movements of the carriage 36. Additionally, set screws 106, 107 operate a switch in a box 95 and positively engage the box to provide upper and lower limit settings for the carriage 36 when used in a non- programmed cycle. The table-driving motor is controlled by a two-speed valve and solenoidoperated valves and is locked, when inoperative, by fluid-pressure applied to each side. The feed rate of the table is controlled by a valve 159, Fig. 7, the amount of overlap between ports 166, 167 being set by a cam 177 rotated by a hand wheel 180 according to graduations on a scale 182. A second feed-speed is obtained by advancing a plunger 173 carrying an adjustment screw 175 thereby reducing the overlap to provide a slower speed. For rapid traverse, the valve 159 is by-passed. The carriage-moving motor is similar to the table motor but runs at only one speed. Surrounding a shaft in the drive to the cutter spindle are a piston and cylinder which are operated in one or other direction to brake the spindle or to clutch it to the spindle motor. A plug-board 215, Fig. 9, is provided into which jacks are inserted to select the events indicated on the right of the board for the particular cycles indicated at the bottom of the board. The dwell periods allow the cutter to produce clear radiused ends at each end of the keyways. A manually operated stepping switch 261 or a similar automatic switch selects the event. If an automatic cycle is interrupted, the stepping switch 261 may be rotated to find the event reached. This is indicated by an increase in brightness in an indicator lamp, the correspondence between the stepping switches causing a resistance in the lamp circuit to be shorted out. By this means an event can be selected manually and an " Event Button " 295 pressed repeatedly until the automatic stepping-switch reaches the same station. An operation can then be commenced from that point. A plurality of limit switches are provided for some functions, e.g. table right, so as to permit close spacing of the trip dogs. If the stepping switch advancing means is not energized when a limit switch is tripped, the slide is stopped. Furthermore, as long as the switches are operated successively, more than one limit switch may be closed at one time without affecting the correct operation of the machine.