Patent GB-541633-A (GB)
Title: Improvements in or relating to vertical broaching machines
IPC: B23Q5/06
Filed: 1940-06-10
Abstract: 541,633. Hydraulic machines. LAPOINTE MACHINE TOOL CO., Ltd. (Lapointe Machine Tool Co.). June 10, 1940, No. 10095. [Class 69 (ii)] [Also in Group XXII] In a metal broaching machine of the pull-down type in which the work is held in a support 20 and one or more broaches are pulled downwards by a hydraulically-actuated slide 61 and puller heads and are returned by a slide 80 and lifter heads 81 the work-support is made rotatable and is fitted with alternate work-receiving apertures 24 and apertures 27 serving as broach-returning stations so that the holder 20 is given two intermittent motions for each complete operation of the machine. The machine is provided with interlocking electric and hydraulic control devices so as to be completely automatic, and so that if any operation is not completed no further action of the machine takes place. As described is connection with a machine of the kind described in Specification 484,759, [Group XXII], and in which a main reversible variable discharge pump P of the kind described in Specification 302,158, [Class 69 (ii)], is used, the plungers 63, 83 for operating the slides 61, 80 are operated from the pump P and an auxiliary pump P<SP>1</SP> by means of solenoid valves 100, 101, 102 which are energized by switches operated by the slides 61, 80 and by cams on the rotary work-holder 20 which is itself driven by a motor M automatically energized. The hydraulic circuit also includes an auxiliary pump P<SP>2</SP>, throttle valves T, T<SP>1</SP>, T<SP>2</SP>, relief valves R<SP>1</SP>, R<SP>2</SP>, check valve C, back-pressure valves 11, 111 for the cylinders 84, 64, and a differential valve D for the pump P. The electric circuit from the mains L, L<SP>1</SP> is controlled by a main switch 110, and three switches 86, 87, 89 : 95, 96, 97 in connection with the slides 80, 61 and switches 40, 54, 55 in conjunction with the worksupport 20. On closing switch 110 the live wire L is connected through switches 96, 54 to a solenoid valve 100 which completes the circuit from the auxiliary pump P<SP>1</SP> to the cylinder 84 which moves the slide 80 and the broaches B downwards through the work and into puller heads 60 on the slide 61. A cam 85 on the slide 80 then closes switch 87 which operates the solenoid valve 101 and causes connection from the auxiliary pump P<SP>2</SP> to a key-operating cylinder 76 which operates in lever 73 to cause a key 72 to lock the broaches B to the slide 61. The lever 73 also reverses a switch 78 and causes operation by the pump P' of a piston 70 which causes operation of the main pump P and consequent lowering of the slide 61. The broaches are thus operated by both pulled and pushed action until the pump P<SP>1</SP> is unloaded by operation of a vent valve V by a projection 116 on a rod carried by the slide 80, and finally the broaches are pulled through the work by the slide 61. At the lower limit of the slide, switch 97 is operated to release the keyoperating cylinder 76, and at the same time the switch 78 is reversed to put the pump P to neutral position, and switch 54 is operated to energize the solenoid 41 and operate a plunger 42 which releases the holder 20 by disengaging the recess 44 and also closes the motor switch 40 which rotates the holder. After the motor has driven the holder through nearly 90 degrees a cam 51 operates a switch 55 to open the motor circuit but this cannot be completed until a notch 44 comes opposite the plunger and thus a complete rotation of 90 degrees is assured before the holder 20 stops. The solenoid valve 102 then causes reversal of the piston 70 so as to move the slide 61 upwards and at first the slide 80 is pushed up by slide 61 until reversal of valve 100 reverses pump P<SP>1</SP> and then the slide 80 is raised more quickly than the slide 61 until the valve V is again operated to unload pump Pi. At the upper limit of slide 61, switch 95 is closed by cam 90 to energize the solenoid 41 and again start the motor M which rotates the holder 20 a further 90 degrees and finally when this is completed a cam 50 operates switch 54 to stop the motor and restart a further cycle of operations. The machine described operates three tools for operation on three work pieces simultaneously in the same manner, but the three tools may perform different operations in succession. Also the number of tools and the extent of the intermittent operation of the work-holder 20 may be varied.