Patent GB-901191-A (GB)
Title: Billet grinding apparatus
IPC: B24B7/02
Filed: 1960-05-03
Abstract: 901,191. Grinding billets. MID-WEST ABRASIVE CO. May 3, 1960 [June 5, 1959], No. 15576/60. Class 60. Mechanism provided in a billet-grinding machine for successively turning each billet B so as to present all its faces for grinding comprises a vertically-movable housing 132, Figs. 2 and 11, a turn-over member 126 which is mounted on the housing for rotation and forward and rearward movement and is provided with supporting surfaces 127, 130 for the billet, means for raising the housing to cause the member 126 to lift the billet from its supports 35 in the machine, means for moving the member forwardly with the billet when so raised, and means for rotating the member, and with it the billet, and thereafter lowering the housing to deposit the billet on its supports with the next face in position for grinding. The mechanism is described as fitted in a machine in which a carriage 10 is loaded with a billet by a loading rack 12, Fig. 1A, and traversed rapidly to the left on rails 14 to the grinding position shown in Fig. 1B where it is reciprocated slowly under a grinding-wheel 56. Each face of the billet is ground in successive bands, the grinding-wheel being fed a step across the face of the billet at each end of each stroke of the carriage, and the turn-over mechanism is arranged to be automatically effective to present a new face of the billet for grinding upon the completion of the previous face and to eject the finished billet when all its faces have been ground. The carriage 10 is moved on the rails 14 by an hydraulic motor 16 driving a drum 17 which is rotatable in the base frame 13 and has a cable 21 wound thereon and connected at opposite ends to opposite ends of the carriage. With the carriage in its initial position, Fig. 1A a billet is fed to it from the loading rack 12 which comprises endless chains 93 having billetengaging dogs arranged, upon the energization of a motor 103, to move the billets along support rails 102 until the foremost billet drops off the latter on to the upper faces of pusher rods 106, 114; the motor 103 is de-energized when the dogs have advanced a distance equal to the width of a billet and may be controlled by an inching button. At this stage, the energization of an hydraulic motor 113 results in the outward movement of the rods 106, 114 so that dogs 107 thereon deliver the billet against rear stops 36, Figs. 2 and 4, on rest pads 35 adjustable longitudinally on the carriage, and a billetactuated switch then energizes hydraulic motors 43 to urge clamps 44 along the pads into clamping engagement with the ends of the billet. The motor 16 is then energized to move the carriage rapidly to the grinding zone, a rapid traverse circuit 223, Fig. 18, then by-passing a restriction 222 in the fluid flow to the motor, and when the carriage reaches the grinding zone the circuit 223 is closed and the motor set for slow speed operation by a dog 54 on the left-hand clamp 44 actuating a limit switch; reversal of the motor to provide grinding reciprocation of the carriage is then effected by dogs 54 on the two end clamps 44 actuating limit switches.  The mechanism on the carriage for turning a billet through 90 degrees so that all its faces can be ground and then ejecting the finished billet comprises two connected L-shaped jaws 126, Fig. 11, mounted for joint movement in a housing 132 which is itself movable vertically in the carriage by linkages operable by hydraulic motors 142, Fig. 2 ; the jaws are carried on the housing by a parallel linkage 145, 151, the link 151 being in the form of an hydraulic motor which can be actuated to swing the jaws through 90 degrees about their pivots 146. A turning cycle of this mechanism consists of elevation of the housing 132 by the motors 142 so that the billet is lifted from the pads 35; actuation of the linkage 145; 151 by an hydraulic motor 162 to move the billet away from the rear stops 36, pivotal movement of the jaws to the position shown in Fig. 13 by the motor 151, lowering of the housing by the motors 142 to deposit the turned billet on the pads 35, operation of the motor 151 to restore the jaws to their normal position, further raising of the housing by the motors 142, operation of the motor 162 to cause the jaws to urge the billet against the rear stops 36, and lowering of the housing; the motors 142, 151, 162 are suitably energized for this purpose by appropriate movements of their control-valves 274, 290, 283 by automaticallyacting time relays included in the control circuit. The grinding-wheel 56, Figs. 1B and 6, is carried at the end of a boom tube 60 which is mounted for oscillation about its axis by mechanism 63 and slidable longitudinal movement within an elongated housing 61 which is itself pivoted on horizontal trunnions in a fixed frame 64. The grinding-wheel is partially counterbalanced by a weight 75 and arranged to be swung vertically to and from its operative position on a billet by an hydraulic motor 76 acting on the housing 61. A further hydraulic motor 78 acting on the boom tube serves to slide the latter outwardly in the housing at each end of the stroke of the carriage for the purpose of positioning the grinding wheel to carry out operations on successive bands of the billet. Rotation of the grinding wheel is through a belt drive 86, Fig. 1B, from a motor 83 mounted on a carriage 87 which is slidable on rails 88 and connected with the boom tube for movement therewith as a unit transversely to the billet. The hydraulic motors are arranged in two separate pressure-fluid systems, as shown in Fig. 18, together with solenoid control valves for the respective motors, so that by the actuation of limit switches and relays in an electrical control circuit an automatic cycle may be performed. With a billet secured on the carriage 10 between the end clamps 44, the operation of a cycle switch results in the setting of the control valve 206 to cause the motor 16 to move the carriage to the position shown in Fig. 1B, rapid traverse occurring as described above until the carriage reaches the grinding- zone, after which the carriage moves slowly to its end position and is thereafter reciprocated slowly for the grinding operation under the control of the limit switches actuated by the dogs 54. Before, however, the carriage starts its first stroke to the right, a limit switch acts to cause the control valves 245, 227 to energize the motors 78, 76 so that the grinding wheel is first advanced outwardly to its correct initial position over the billet and then lowered on to the billet. Only when the pressure in the circuit of the motor 76 is sufficient to open a relief valve 242 is a pressure switch 243 actuated to cause energization of the motor 16 in reverse for the first grinding stroke. At the end of each stroke of the carriage, but before the start of the next, a limit switch sets the control valve 245 for the energization of the motor 78 in a direction to advance the grinding wheel across the billet in readiness for grinding the next band on the billet, the extent of such advance being determined by a timer which is energized by the closure of a limit switch and stops the motor when de-energized. When after' successive advances, the grinding wheel has reached its outer limit of travel, a limit switch sets the circuit to prevent further advance of the grinding wheel, stop the carriage at the end of its next stroke, release the end clamps 44, energize the motor 76 in a direction to raise the grinding wheel, and, consequent upon the closure of a switch by the raised boom tube 60, energize the motor 78 to withdraw the grinding wheel to its initial position and set into operation the mechanism described above for turning the billet through 90 degrees. When the billet has been re-positioned on the pads 35 and the end clamps 44 operated, the next face of the billet is similarly ground and the same procedure follows for the other two faces. When, after the last face of the billet has been ground; the billet is unclamped and the grinding wheel moved to its initial position, the circuit is so set by the actuation of relays, which serve in effect to register a count as each face is operated upon, that the carriage is moved rapidly back to its initial loading position, whereafter the motors 142, 151 of the turn-over mechanism are energized to lift the billet from the carriage and turn it through 90 degrees for ejection to the rear of the carriage. ; .