Patent GB-565968-A (GB)
Title: Hydraulically operated table reciprocating mechanism for grinding machines
IPC: B24B47/06
Filed: 1943-06-17
Abstract: 565,968. Grinding. NORTON CO. June 17, 1943, No. 9779. Convention date, June 17, 1942. [Class 60] [Also in Group XXIX] The reciprocating table of a grinding-machine is operated by fluidpressure means comprising a cylinder on the table operated through a piston type reversing - valve, the actuation of which is initiated by a reversing lever and adjustable dogs, and means is provided whereby the movement of the reversing valve is positively effected by fluid pressure. The machine has a base 10 on which is slidable the table 11, to which is secured a cylinder 12 containing a pair of spaced pistons 15, 16 connected by hollow rods 17, 18, respectively, with hollow brackets 19, 20 on the base 10 ; the base has therein a reservoir 21 from which fluid is drawn by a pump 23 and to which exhaust fluid returns. A control valve 25 is provided having a stem 28 with pistons 29-33 thereon, the pistons 29, 33 being of smaller diameter than the others ; as shown, fluid under pressure passes from valve chamber 34 through ports, passages and pipes to chamber 40 in bracket 19, thereby moving the cylinder 12 and table 11 to the left. The speed and stopping or starting is controlled by a valve 51 to which exhaust fluid from the cylinder passes, by a pipe 50, through a V- shaped port 52 which may be covered more or less by rotation of the valve stem 55 to bring the inclined end of piston 57 over the port ; the fluid passes from the valve to a pipe 54 leading to the reservoir 21. The piston 57 is adjusted rotatably by a knob 58 on the stem 55 and is held in adjusted position by a serrated portion 59 of the stem engaged by a spring plunger 60 ; this allows axial movement of the valve without rotation, the axial movement being effected by a lever 65 pivoted at 66 and serving to start or stop the reciprocation of the table 11. When in the stop position, the port 52 is covered by piston 57 and a space 82 between piston 57 and a piston 56 allows communication between pipes 80 and 81 leading to the two hollow brackets 18, 19 respectively, whereby movement of the table 11 is not resisted by fluid pressure. Pressure fluid may pass from the valve chamber 34 to valve chambers 100 or 101 formed by pistons 29 and 30, 32 and 33 respectively and from those chambers through ports 102, 103 to reservoirs 98, 99 ; the difference of area of pistons 29, 30 and 32, 33 serves to allow pressure fluid to move the valve when given a slight initial displacement by means of a lever 85 pivoted at 86 and engaged by dogs 92, 93 mounted adjustably on the table 11. In order to control exhaust from the reservoirs 98, 99, and thereby render positive the movements of valve 25, a rotary valve 105 is provided comprising disc members 106, 107 angularly adjustable and locked in adjusted position by a screw 108, the member 106 being held by a strap 110 secured to a support 111 and clamped by a screw 112 to hold the strap in adjusted position. A rotor 113 is mounted in the members 106, 107 and is movable by a lever 114, the angular motion of which is limited by stops 117, 118, and which is connected through a spring friction device 120-125 and link 115 to the valve 25. A pipe 130 leads from reservoir 98 to a port 131 in member 107 and a pipe 132 leads from reservoir 99 to a port 133 in member 106, and the central chamber 134 of rotor 113 is connected by a pipe 135 with reservoir 21 and has therein passages which communicate with ports 131, 133 when the rotor is turned ; the valve 105 thus serves to allow free exhaust from reservoir 98 whilst preventing exhaust or leakage from valve 25 to return to reservoir, and similarly with reservoir 99, so that the full effect of fluid pressure may be utilized to shift the valve 25. Specification 463,334 is referred to.