Patent GB-778060-A (GB)
Title: Improvements in or relating to record controlled machines
IPC: B23Q5/26
Filed: 1953-05-13
Abstract: 778,060. Grinding. GOLDMANN, B. M. G. Aug. 13,1954 [May 13, 1953], No. 13373/53. Class 60 [Also in Groups XXII and XXIV] A machine comprises means for moving a part 3 in two directions, and means for driving a paper, metal or plastic record tape past two pneumatic pick-ups each arranged to cause the part to be moved in one direction a unit amount for each unit of data on the tape which, during operation, registers with that pick-up. For moving the slides 2, 3 of a milling machine, four tracks are provided on the tape representing the directions N, S, E, W. Two additional tracks for up-anddown movement may also be provided. The holes may be consecutive or two holes may be aligned to give a 45 degrees movement. Further holes can be punched and holes covered to modify a tape according to inaccuracies produced in a test workpiece. When a hole in the tape E, Fig. 5, registers with an air jet 12, reduced pressure, acting on a valve 19 allows a spring to move the valve to connect lines 15 and 20. A piston 24 carrying a pawl 26 is thus moved to rotate a ratchet wheel 22 connected to a feed screw 23. A second pawl moves the screw in the reverse direction. The piston of valve 19 may operate a magnetic brake at the end of stroke. In a modification, the piston 24, Fig. 8, is mounted in a movable cylinder 31 so that the screw 23 is turned simultaneously by the ratchet 26 and a ratchet 35 on a lever 36. A resilient or worm reduction drive may be fitted between the ratchet wheel 22 and its shaft. The movements of a piston and/or cylinder may be limited by adjustable stops &c. or a port may be opened at or near the end of the stroke of a ratchet piston to cut off the air supply thereto by actuating the valve 19. To relieve the mechanism of the force of moving the machine table, the ratchet wheel 49, Fig. 9, rotates a screw 50 mounted in a nut 51 on the table. The screw carries a disc 52 upon which two jets 53, 54 impinge. Movement of the wheel 49, screw 50 and disc 52 closes one jet and causes movement of a cylinder 61 and a piston 76 to allow oil to pass through an inlet 76a to a cylinder 47. Within the cylinder is a piston 48 connected to the table 45 which moves to its new position and carries with it the screw 51 to restore balance to the jets 53, 54. The screw 50 may be spring-loaded to eliminate back-lash or account may be taken on the tape of a known back-lash at each reversal of movement. Furthermore, clutches or electrical switch gear may replace the valves and control a mechanical or electrical feed of the table 45. In a modification, the relay valve directs air to one or other of two air motors, or one or other side of a single motor, connected to the slide lead-screw. To produce a smoother profile on a curved workpiece a shroud g, Fig. 10, is placed over a tape drum E<SP>11</SP>. According to the number of holes registering with exhaust apertures in the drum so the speed of a motor L is controlled by a tapered relay valve k<SP>1</SP> Cumulative errors are preventd by a cam W in the shaft w of the motor L driving the leadscrew n<SP>11</SP>. The cam W allows more or less air to escape from a line v controlling a valve q which is also acted upon by a line p communicating at o with the central tape hole. Movement of the valve q modifies the movement of the valve h<SP>1</SP> to prevent over-running, the valves being duplicated to control movement of the motor L in the opposite direction. In a further modification the feed motor is supplied with a series of measured volumes of air. Speed-controlling. A similar arrangement may be provided for controlling the speed of the spindle motor 163, Fig. 12, the motor being controlled by the valve 159 according to the pressure under a shroud 154 over the control section of a speed-control tape 153. Alternatively, a valve 165, Fig. 13, may be controlled to rotate a rheostat 170 in the circuit of an electric motor rotating the spindle. If an exact control of speed is required, as when turning a fluted spindle, a system as in Fig. 10 is used to prevent a cumulative error. To compensate for reduction in diameter due to sharpening, a tapered cutter 230, Fig. 15, is used and is adjusted axially after sharpening. To maintain the tool normal to the surface it is mounted on a bracket 234 moved angularly by a worm 235 controlled by two tracks on the tape. The slide 241, on which the bracket is mounted. and the slide 239 carrying the work are each controlled by two further tracks. In a modification, a cylindrical grinding, lapping or milling cutter is laterally adjustable on a slide 242, Fig. 18, after sharpening, the slide being mounted in a sleeve 243 which can be rotated by a worm 244 controlled by two tracks to maintain the tool surface normal to the work. For cutting surfaces of varying profile angle, the sleeve is adjustable about an axis parallel to the plane of the curve. In a lathe, a tool is moved angularly by a worm 255, Fig. 21, and axially by a screw 256, and is traversed by a further screw, the control being exercised by six tracks. A further track may index a turret. Lubricating and cooling cutting tools. Tracks may also be provided to turn cutting fluid supplies on and off. The work and/or the tool can be controlled in grind-. ing or work transfer machines.