Patent GB-995125-A (GB)
Title: Apparatus for cutting the surfaces of bars, billets and other articles
Inventor: MILLS EDWARD CECIL
IPC: B24B47/06
Filed: 1960-06-17
Abstract: 995,125. Grinding. BAYLISS JONES & BAYLISS Ltd. July 27, 1961 [June 17; 1960], No. 21273/60. Heading B3D. A machine for cutting the surface of a succession of similar bars for the purpose of exposing the metal near the surface skin for inspection comprises means for advancing a succession of the bars through the machine, a grinding tool arranged to be advanced towards and retracted from the surface of each successively advancing bar by means of an hydraulic pressure-operated device, means arranged to be actuated by the advancement of each bar in turn for supplying liquid under pressure to the said device prior to the start of each cutting operation to advance the grinding tool into operative engagement with the bar, and means for feeding at the end of each successive cutting operation the same predetermined amount of liquid to the device to effect retraction of the cutting surface of the grinding tool by the same distance from the path of advancement of the bar. As shown in Figs. 2, 3 and 5, grinding is effected on all four sides of a bar 1 simultaneously by pairs of grinding wheels 16, 17 and 44, 45 urged into contact with the vertical and horizontal faces, respectively, of the bar. The wheels 16, 17 are carried by arms 18, 19, Fig. 3, pivoted on shafts 20, 21 which are driven by motors 22, 23 and rotate the wheels through chain drives. The motors are mounted on a platform 24 carried by horizontal axles 26 in a cradle 27 which is supported by a pivot 29 at one end and at the other end is adjustable by a hand wheel 32 to adjust the normal vertical position of the wheels. A sinuous cut on the sides of the bar is effected by vertical reciprocation of the wheels caused by oscillation of the platform 24 by a motor 37 via a crank 36 and connecting rod 35. The wheels 44, 45, which similarly act on the upper and lower faces of the bar, are carried by pivoted arms 46, 47, Fig. 5, and driven by motors 50, 51 on a platform 52 oscillatable in an adjustable cradle 55, oscillation of the platform to reciprocate the wheels being effected by a motor 59 through a crank drive 60, 61. Movement of the wheels 16, 17, 44, 45 to and from grinding position is effected by hydraulic cylinders 38, 39, Fig. 3, and 62, 63, Fig. 5, acting on the respective arms 18, 19, 46, 47. At the entrance end of the machine the bar passes between pairs of driven rolls 2, 3 engaging the upper and lower faces of the bar and pairs of guide rolls 8, 9 engaging the side faces, and similar sets of rolls 64, 65, 70, 71 are provided at the leaving end of the machine. The upper pairs of rolls 2, 3 and 64, 65 are arranged to be raised and lowered by pneumatic cylinders and one pair of each of the sets of guide rolls 8, 9, 70, 71 is manually adjustable to and from the other set. The machine is provided with a hydropneumatic control circuit as shown in Fig. 1, in which switches 5, 15, 68, Fig. 2, actuated by successive bars as they enter and leave the machine control valves 147, 145, 146, 148 arranged in a compressed air line for respectively operating the cylinders 42, 43 of the upper rolls 2, 3, the hydraulic cylinders 38, 39, 62, 63 controlling the position of the grinding wheels and the cylinders 66, 67 of the upper rolls 64, 65. The cylinders 62, 63 are arranged to operate just after the cylinders 38, 39, and the two sets of cylinders are disposed in identical circuits of which it will be seen that the circuit of the cylinders 38, 39 consists of reservoirs 202, 205, 206 connected above the liquid level with the compressed air line 300 (with the reservoir 202 at lower pressure) and controlled by pneumatic valves 133, 134, 135, actuated by the valve 145. Operation of the valve 145 a brief interval after the rolls 2, 3, have been closed on to an advancing bar sets the valves 133, 135 to connect the inner ends of the cylinders 38, 39 with the reservoir 202 and permit pressurized fluid from the reservoir 205, 206 to urge the grinding wheels 16, 17 into contact with the bar; at the same time the valve 134 opens the right-hand of a pump cylinder 143 containing a unitary triple piston 171, 172, 173 to atmosphere whereby pressure liquid is fed to the spaces in advance of the pistons 172, 173 and the three pistons are moved to the right. While liquid is thus displaced into the spaces in advance of the pistons 172, 173 until they have completed their stroke, the wheels continue to be fed forward as wear occurs because of the liquid displaced from the cylinders to the reservoir 202. As a bar leaves the machine, it successively actuates the limit switches with the result that the valves 147, 146, 145, 148 appropriately act upon the cylinders 42, 43, 38, 39, 62, 63, 66, 67 to raise the rolls 2, 3, withdraw the grinding wheels and raise the rolls 64, 65. The actuation of the valve 145 (and similarly for the valve 146) operates the valves 133, 135 to stop liquid flow from the cylinders 38, 39 to the reservoir 202 and through the valve 134 causes compressed air to move the triple pump piston 171, 172, 173 leftwards until halted by an adjustable stop. Liquid displaced from the spaces ahead of the pistons 172, 173 is forced into the cylinders 38, 39 to move the grinding wheels to retracted position. The pistons 172, 173 always move through the same distances so that the same volume of liquid is displaced in successive operation and the grinding wheels are always displaced by the same constant distance. However, since because of wear the wheels are advanced slightly in successive grinding operations in order to maintain grinding engagement, each retraction will be to a position slightly in advance of the previous retracted position and so ensure that in the next advance the wheels will be brought into correct timed engagement with the foremost end of the next bar. The hydraulic circuit of the cylinders 38, 39 (and 62, 63) is provided with a pressure-responsive switch 139 to provide a warning or cut-out should the pressure in the system rise above a predetermined maximum and, if desired, effect retraction of the wheels.