Patent GB-678780-A (GB)
Title: Tracer-guided reproducing lathe
IPC: B23Q35/18
Filed: 1950-12-18
Abstract: 678,780. Copy-turning. TURCHAN, M. Dec. 18, 1950, No. 30824/50. Class 83 (iii). A copying-lathe has a main cross-slide 24 on a power-operated carriage 21, a central auxiliary cross-slide 36 mounted on the cross-slide 24 for movement diagonally of the direction of movement of the latter and a top auxiliary cross-slide 44 which carries the tracer 61 and tool 153 and is mounted on the central slide for movement transversely of the direction of movement of the central slide, the auxiliary slides being moved one at a time only. The lathe may be operated hydraulically or electrically. The carriage 21 is fed longitudinally on the lathe bed, either hydraulically or by a lead-screw 22 and nut 23, and carries the cross-slide 24 which is transversely movable by power means or by a hand wheel 25 and lead-screw. The central slide 36 is movable on the cross-slide at an angle of, preferably, 45 degrees to the carriage movement and carries the top slide 44 which is movable at an angle of, preferably, 90 degrees to the movement of the central slide 36. A tool-holder 158 is swivel-mounted on undercut ways 155 on the top slide by a clamping arm 161 threaded on aT-bolt 159. Movement of the top and central slides is effected, respectively, by a hydraulic cylinder 45 sliding on a piston 47 fixed to the central slide and by a cylinder 38, Fig. 8, sliding on a piston 39 fixed to the crossslide 24. The tracer 61 is carried on a bracket 50 adjustable on the top slide 44 by a hand wheel 57 and lead-screw and has a tip 71, Fig. 9, held by an adaptor 71a and knurled nut 72, the tip engaging a templet 35 on a frame 34. A cover 67 and a slot 70 to facilitate removal of the adaptor 71a are provided on the arm. A ball-bearing 62 with conical surfaces 65 and a ball 76 engaging conical surfaces 74, 77 on the arm and on a valve 78, respectively, support the arm so that lateral pressure on the tracer tip causes downward movement of the valve against the action of an adjustable spring 101. A stabilizer comprising a pin 103 eccentrically mounted in ball-bearings 105 and passing through a slot 102 in the arm prevents rotation of the arm while allowing it to move in a direction perpendicular to the pin. A disc 99 on the lower end of the valve stem 98 is linked to a hand lever 119, Fig. 2, so that the position of the valve 78 can be manually controlled. Delivery and return pipes 92, 93 connect the tracer to a hydraulic unit 120 and other pipes 121, 122 connect it to a change-over valve 123, one pipeline including also a shut-off valve 124. The manually-rotatable change-over valve element 136, Figs. 8, 11, 14 has four annular grooves connected by pipes to the cylinders 38, 45 and by axial passages 142, 145, 148, 149 of appropriate length to four ports 143, 144, 146, 147, different pairs of which, by successive 90 degrees rotations of the valve element, can be connected to the tracer-controlled fluid pipes 121, 122. Oil seepage from the tracer and change-over valves is led back-to the hydraulic unit through pipes 91. Lubricating passages.-Lubricant is supplied to the carriage 21 through a valve 151, Fig. 1, and pipes 150, 152, the latter pipe being formed within the bracket 33. Operation. When cutting the surfaces 164, Fig. 2, on work 29, with the carriage moving from right to left, the position of the changeover valve is that shown in Fig. 11, in which pressure-fluid controlled by depression of the tracer valve on meeting the rising surfaces of the templet 35 is directed only to cylinder 38 and causes a withdrawal of the slide 36 and of the tool. During the period while the parallel surface 165 is being cut, the operator rotates the change-over valve through 90 degrees counterclockwise into the position of Fig. 14 so that pressure-fluid controlled by raising of the tracer valve on meeting the depression in the templet is directed only to cylinder 45 to cause inward feed of the slide 44 and of the tool. Rotation of the change-over valve through 180 degrees from either of the above positions will cause pressurefluid controlled by raising or lowering of the tracer valve to go to the same cylinder as before but to the opposite end so that the hand of reproduction is reversed. In cutting the front and rear faces of work such as that shown in Fig. 1, the carriage 21 is stationary and the cross-slide 24 is traversed by hand or power with the tracer controlling cylinder 38 for cutting the front face or cylinder 45 for cutting the rear face.