Patent GB-650050-A (GB)
Title: Improvements in or relating to hydraulic apparatus
IPC: B30B15/16
Filed: 1947-12-17
Abstract: 650,050. Lathes. MAY, E. M. Dec. 17, 1947, No. 33280. Convention date, Dec. 30, 1946. [Class 83 (iii)] [Also in Group XXIX] The various operations' of a lathe are controlled automatically by a plurality of cylinder- and-piston fluid transmitters 9, Fig. 3, (see Group XXIX), which are controlled in turn by flexible cam strips 33 bent circumferentially around, and detachably secured to, a rotatable cam drum 27, the cam strips being engaged by pivoted levers 36 for actuating the pis - tons of the transmitters. The various transmitters and the cam drum may be mounted on a frame in a portable cabinet adapted to be spaced from the controlled machine, or the mechanism may be mounted on the frame of the machine. As shown in Fig. 3, the turret slide 74 of a lathe is operated by an hydraulic motor 75 fitted with an hydraulically-actuated follow-up valve controlled by one of the transmitters 9. Pressure fluid is supplied to the motor 75 from a pump 88 through a pipe 92a fitted with a spring- pressed spool valve 81. For actuating this valve, low-pressure fluid from a transmitter 9 acts upon a piston 82 and, through the piston rod 83, operates the valve 81 ; the piston 78 of the cylinder 75 carries an arm 85 provided with a follower rod 86 movable in the cylinder 80b. To control the pressure of fluid delivered to the cylinder 75, a byepass valve 94 in the system is associated with a relief valve in the form of a spring-pressed ball 96 ; the pressure exerted by the spring 97 on the ball 96 (and therefore the pressure at which the relief valve opens) is controlled by low-pressure fluid from another of the transmitters 9 acting through a piston 100. The drum 27 is driven from a motor 43 through gearing, the speed of which can be controlled from one of the transmitters 9 acting through a spring-controlled piston 69 upon the operating lever 44a of the gearing. An emergency switch 50 in the circuit of the motor 43 is opened if any of the transmitters 9 should fail to operate correctly, or, if desired, automatically at the end of one revolution of the drum 27 by the coaction of a pin 59 on the drum with a lever 57. Each of the cams has a deep notch which serves at a certain point in the cycle to operate the pistons in the transmitters so as to replenish the cylinders with pressure fluid. In the arrangement shown in Fig. 6, the transmitters 9 are arranged, respectively, to control (a) the advance and retraction of the turret 108 through an hydraulic motor 75, (b) a collet chuck mechanism 106 for gripping and advancing the work to the tool through an hydraulic motor 75<SP>1</SP>, and (c) a cross-slide 107 through an hydraulic motor 75<SP>11</SP>, all these members being provided, if desired, with positive stops to limit their movements. The pressure of working fluid and speed of rotation of the drum can be varied as described above at appropriate stages in the cycle. If desired, the transmitters 9 may be arranged in separate sets which are arranged to operate alternately for controlling a large number of operations or several machines co-ordinately. For example, the circuits of the motors and switches of two sets of control units are so associated that each set effects control automatically and alternately. In another embodiment, the variable-speed units of two cam drums are controlled so as to drive the two drums synchronously the setting of the variable-speed unit of one drum being fixed and the setting of the corresponding unit of the other drum being controlled jointly and oppositely by transmitters 9 controlled by both drums. The Specification as open to inspection under Sect. 91 refers also to the application of the invention to copying-machines in which a tool engages the work under the control of a model. This subject-matter does not appear in the Specification as accepted.