Patent GB-693100-A (GB)
Title: Semi-automatic control device for screw-threading machines of the opening head type and the like
IPC: B23G1/04
Filed: 1952-03-25
Abstract: 693,100. Screwing. ANCIENS ETABLISSEMENTS J. HOTTIAUX. March 25, 1952 [March 29, 1951], No. 7676/52. Class 83 (iii). [Also in Group XXIII] A screw-cutting machine has a self-opening die-head 2, which is opened and closed by a collar 3 provided with an arm 80, the arm being moved to open the die-head by an adjustable dog 77 on a rod 76 connected to the reciprocating work carriage 6 and moved to close the head by a piston 61 to which pressure fluid is supplied by a valve 41 under the control of another adjustable dog 75 on the rod 76. The fluid used is the cutting fluid or oil, which is supplied to the tool and work during the cutting period but is automatically shut off at other periods. The oil is drawn from a sump 10 by a pump 9 and is delivered through a pipe 12 to a piston 16 which retracts the workcarriage 6 and through a pipe 14 to the valve box 15 which contains the distributing valve 41 and a valve 45 operated by an adjustable rod 86 connected to the collar arm 80 to shut off the supply of cooling oil to a nozzle 97. A spindle 19 having a hand wheel 28 has a pinion 18 engaging a rack cut round the periphery of the rod of the piston 16, and a pinion 23 engaging a rack 24 loaded by a spring 25 and carrying a wedge 27 which engages between rollers 29 on the lower ends of pivoted vice-jaws 7. Operation.-At the completion of a screwing operation, when the carriage 6 is in its rearward position, the hand-wheel 28 is turned in the direction of the arrow f<SP>4</SP> to withdraw the wedge 27 and allow a spring 32 to open the vicejaws for removal of the finished work and replacement by new work. The hand wheel is then first released to allow the wedge to be returned by the spring 25 and clamp the work 26 and then rotated further in the direction opposite to arrow f' to move the work-table forward until the work is engaged in the diehead. The consequent movement of the rod 76 disengages the finger 74 on the dog 75 from the valve 41, and its spring 44 returns it to the position shown in Fig. 4, in which oil flows through the chamber 48 past the open valve 45 and through pipes 93, 94 to the nozzle 97 over the die-head. At the same time, oil in the cylinder space 60 for the piston 61 is allowed to exhaust through passages 58, 57, chamber 50 and a pipe 55, Fig. 1, to the sump so that the piston 61 is moved into position A by its returnspring 62. At the end of the screwing operation, the dog 77 on the rod 76 moves the arm 80 to open the die-head and the rod 86 closes the valve 45 to shut off the supply to the nozzle 97. The pressure in the pipes 12, 14 then rises to a maximum value and the piston 15 moves rearwardly to retract the work-carriage 6 until the dog 75 meets a stop 90 on the machine frame. The finger 74 has moved the valve 41 to the position of Fig. 3 and the fluid at high pressure in the pipe 14 is led through the passage 58 to the piston 61 so that it is moved from A to B. This movement shifts the arm 80 so that the die-head is closed again and locks itself in the closed position, and so that the rod 86 opens the valve 45, although there is no flow to the nozzle 97 since the valve 14 has closed the connection between pipe 14 and chamber 48. Piston 61 continues to move into position C where it uncovers a by-pass 65 leading to the sump through a valve 91 which is set to give a pressure in the system sufficient to hold the pistons 16, 61 in their rearward positions. A spring-loaded valve 66 is provided within the piston 61 and is opened to by-pass the pressure to a sump return 72 if the thrust on the adjustable abutment 87 on the arm 80 rises beyond the normal value required to close the die-head. The ball-valve 51, Fig. 4, opens if the delivery to the nozzle 97 is completely or partially restricted by the cocks 95 or 96. The cock 100 is provided for adjusting the return speed of the carriage 6.