Patent GB-549422-A (GB)
Title: Improvements relating to hydraulically-operated machine tools
IPC: B23D3/02
Filed: 1941-07-14
Abstract: 549,422. Hydraulic machines; metal planing. BERRY & CO., Ltd., H., and CORIN, P. G. July 14, 1941, No. 8849. [Class 69 (ii)] [Also in Group XXII] A hydraulically operated machine-tool such as a cutting- tool used in a machine for cutting internal longitudinal grooves or splines in cylinders e.g. for cutting tapered splines in the bore of a gun-baffler cylinder is constructed with a ram 7, Fig. 4, for moving the cutting-tool relatively to the gun buffer 56 which is mounted fixedly relatively to the cylinder 6 in which the ram works, and the motion of the ram is produced by liquid supplied by a continuously driven pump 11 the supply of fluid from which is controlled by a choke valve 24 arranged in the supply pipe 19, and by a loaded relief valve 25 which by-passes surplus fluid to a suction pipe 20 leading to the pump reservoir 21. The valve 24 can be operated by hand or automatically e.g. by ratchet-controlled mechanism adapted to stop the machine after a given number of operations. The supply of liquid to the left end of the cylinder 6 is controlled by a shuttle valve 15, Fig. 8, arranged in a cylinder 12 connected to the outlet of valve 24, the valve 15 being operated by a pilot valve 16 which controls the supply of pressure fluid to the bore 13 in which the valve 15 works and so causes the valve 15 to assume positions in which the pipe 19 is connected to the cylinder 6 or to exhaust via passages 18, 17, respectively which are of arc form and are connected to passage 13 by a series of radial passages 23, Fig. 9 (not shown). The valve 16 is operated by a rod 31 fitted with adjustable stops 32, 33 which are engaged by a pivoted tappet 35 so as to pernut ot automatic reversal of the motion of the ram 7 and associated cutting-tool. The tappet 35 can be moved out of operative position when it is desired to prevent automatic reversal. The hollow ram 7 has an extension 8b connected to a delivery pressure pipe 28 branching from the pipe 19 and arranged to deliver constant pressure to the inside of the ram 37 under control of a throttle 28a which is set for a constant opening which cannot be readily altered. This pressure on the ram 7 opposes the motion of the tool in the cutting direction but causes a quick return when the cylinder is connected to exhaust. The gun buffer 56, Fig. 4, is secured in bearing members 57, 60 by means of a collet 59 and clamp 58 and by a hinged cap 60a which is fitted with a coupling for admitting a coolant which is forced by a pump 61, through the work. The cutting-tool 42, Fig. 10, is pivotally mounted in a tubular carrier 41 and is pressed inwards by a spring 43 and outwards by a cam 44 which co-operates with a profile bar 45 to guide the tool. The cam 44 is pivoted to a screw 44a by means of which the cam can be adjusted automatically or by hand between successive operations. As shown this adjustment is effected by a nut driven by bevel gearing operated by a hand-wheel 67, and a settable indexing device is provided to control the amount of adjustment given between each successive cut. The tool is adapted to make a rough cut at a high speed and finally a finishing cut at a lower speed, and at the end of each series of cuts the machine is stopped or a signal device operated by the engagement of the end of the screw 44a with an adjustable screw stop 70, Fig. 4, or with a similar one 71, Fig. 13 (not shown), both mounted in a pivoted plate which can be set to bring .the desired stop into line with the screw 44a. The work is positioned by a retractable indexing plunger 63, Fig. 4, withdrawable by a lever 64 and adapted to engage recesses in the collet 59 or in a sleeve member secured to the gun. When one spline is finished the work is indexed in correct position to receive a further spline. The cutting-tool forms the subject-matter of Specification 549,445, [Group XXII].