Patent GB-802677-A (GB)
Title: Improvements in automatic fluid-actuated control and operating mechanisms for lathes and other machines
Inventor: HILL HARRY RONALD
IPC: G05B19/44
Filed: 1953-10-19
Abstract: 802,677. Programme control of machines. TECALEMIT, Ltd. Jan. 19, 1955 [Oct. 19, 1953], No. 28835/53. Class 83 (3). Automatic fluid-actuated control and operating apparatus for lathes and other machines comprises a master control and sensing unit, a number of slave control and actuating units for operating mechanisms such as stopping and starting devices, feed devices and chuck opening and closing devices, the sensing assembly having a number of fluid ports registering with perforations in a sensing member and allowing the passage of a sensing fluid through the ports and means which restrict the operation of the master control unit for a new set of operations until the completion of predetermined operations by all the mechanisms which have been actuated. In the application of the invention to a turret lathe, Fig. 17, five controls are employed comprising a " start-stop " control 301, a forward reverse control 302, a bar-check control 303, a cross-slide control 304 and a turret traverse control 305. All these controls are operated by double-acting fluid-pressure rams 306-310 respectively, and each is provided with an actuating unit 311-316, respectively, which work in conjunction with limit valves. The actuating units are connected by small diameter air pipes 316-320 to a master control unit (see below) and pressure operating air is supplied to the rams 306-310 by service air lines 321-325. Master control. A single perforated sheet may be mechanically or manually inserted to give a required sequence of operations, but, an endless steel tape 9, Fig. 4, is employed in the example described. The tape passes over sprockets 5, 6, the latter being adjustable to tension it. Each control requires two rows of perforations so that the width of the tape is such as to include all the perforations required for all the controls employed plus an additional row of " master " perforations. A number of tapesone for each control-may be employed in place of one broad tape. The tape is fed between the upper and lower assemblies 17, 15, respectively, of a sensing device of which the upper assembly moves vertically on columns 18 moved by a roller 31 on a lever 30. A transverse section of the valve arrangements of the sensing device is shown in Fig. 11, with all the valves in a single plane, but, in practice, a staggered arrangement is employed. Each control has a pair of sensing valves, the opposite passages 161, 162, Fig. 9, and 163, 164 of which are brought together as the head 17 falls. Seals 165 of rubber or plastic material press against the opposite faces of the tape 9 and either seal off the connections between the upper and lower assembly, or, where a perforation in the tape is brought into line, an airtight connection is formed between the two assemblies which operates valve mechanism passing air to a pneumatic relay system which eventually operates further valves for the controls described above. The connection of passages 161, 162, Fig. 9, allows air to pass from a manifold 170 to depress a valve 173 against a spring 174, air is then passed from lower manifold 171 to small air line 141 equivalent to one of the lines 316-320 referred to in the lathe embodiment above. The actuating unit for a particular control is thus operated and, through valve arrangements, after actuation, returns a pressure signal back through the line 141. The valve 173 is released and rises previous to this by manifold 170 being connected to exhaust, so that the return pressure through line 141 passes to opening 164 and raises a feeler valve 181 which has passed through a further perforation in the tape. Raising of the valve 181 connects a pair of lines 183, 184, and if all the controls operate correctly air is passed to a piston and cylinder device arranged behind the master control chamber 61, Fig. 4, which indexes the tape to bring a fresh set of perforations into sensing position and also releases the stem 62 of the piston valve of the master control. The head 17 is automatically raised before the fresh indexing operation. If one of the controls fails to operate the appropriate valve 181 remains down and the tape does not index, the apparatus thus coming to rest and indicating a fault to the operator. The sensing fluid may be either a gas or a liquid but compressed air is preferably employed. The control medium may also be a liquid or a gas, but, electrical means may be employed for operating the actuating units from the master control.