Patent GB-351522-A (GB)
Title: Improvements in work supporting and rotating mechanism for grinding machine
IPC: B24B5/42
Filed: 1930-03-24
Abstract: 351,522. Work holding and rotating devices for grinding machines. TRIGGS, W. W., 57, Lincoln's Inn Fields, London.- (Norton Co. ; New Bond Street, Worcester, Massachusetts, U.S.A.) March 24, 1930, No. 9401. [Class 60.] A work supporting and rotating means for a grinding machine, particularly a double-headstock machine for crank shaft grinding, is provided with a single manually-controlled lever which when moved in one direction controls the work-rotating mechanism and when moved in another direction actuates hydraulic means to unclamp the work. The sliding work-table 11 is provided with a pair of work-supporting heads 14, 15 which may in some cases be adjustably mounted. The heads carry work-spindles 16, 17 respectively, journalled in partial bearings 18 which are fitted with adjustable floating bearing members 19. The spindles are driven from a power pulley 35 through a friction clutch 44, chain 40, shaft 32 and chains 29, 30. The friction clutch is actuated by a sliding cone member 45 controlled by a handle 50 acting through a link 55 and lever 49, the handle 50 being movable about the longitudinal axis 51 and also about the transverse axis of a stud 52. When the clutch is disengaged the cone member 45 engages with a fixed surface 58 to brake the driving shaft and bring the spindles quickly to rest. The spindles 16, 17 are provided with members 60, 61 to which the work-supporting heads 63 are secured. Each head consists of a partial bearing 65 which supports one end of a workpiece such as a crank shaft 67 and which co-operates with a clamping screw 70 mounted on a lever pivoted at 69. This lever has a ball connection 73 with one arm of a bell-crank lever 72 forming one member of toggle links 79, 72, the toggle being straightened to clamp the work by means of a rod 86 acting through connecting members 87, 90 and urged forward by a spring 97. To unclamp the work both the rods 86 are withdrawn by fluid pressure supplied through a pipe 116, Fig. 4, to a piston valve 120. When this valve is in the position shown in Fig. 4 pressure fluid is admitted through pipes 126, 127 to cylinders 128, 129 thus operating the pistons 102, 103 which act through levers 106, 107 to withdraw the rods 86 against the spring pressure. When it is desired to clamp the work the valve is shifted to the dotted position in Fig. 4 so that pressure fluid is cut off from the cylinders and the rods 86 are moved forward by the springs, the pressure fluid from the cylinders being exhausted through a pipe 138. If desired a pipe 145 may connect the valve to the cylinders 102, 103 so that when the valve is in its lower position the pressure fluid may be used to assist the clamping pressure of the springs 97. The valve spindle is interconnected with the clutch operating lever 50 which works in a gate 130 so that the clutch 44 may be engaged to rotate the spindles only when the valve is in its lower position wherein the work is securely clamped. In order to prevent the work from dropping out of the gripping heads when the clamping screw is withdrawn the rod 86 is provided with a projection 142 which coacts with a fork 141 so that the rod 86 can only be operated when the bearing member 65 is located beneath the work.