Hydraulic closing device for kraftschluessigen closing of shapes in two steps in casting machines

摘要

1,212,510. Injection moulding. LYMING TON MACHINE WORKS Ltd. 10 April, 1968 [12 April, 1967], No. 16877/67. Heading B5A. [Also in Division F1] An hydraulic ram 3, especially for operating the movable mould clamping member 4 of an injection moulding machine, is moved initially by liquid displaced by a piston 12a through a line 9 into the ram cylinder 1, and thereafter the liquid in the cylinder 1 is intensified by pressurizing a cylinder 8 containing a piston 7 having a rod 6 extending into the cylinder 1. The piston 12a is moved in a cylinder 11a by liquid supplied through a line 13 connected to a cylinder 11b containing a piston 12b smaller than and fixed to the piston 12a. When the ram 3 has completed its stroke, liquid is directed through a line 15 to act on the intensifier piston 7, a valve 10 closing to prevent flow from the cylinder 1 to the line 9. To return the ram 1, liquid is simultaneously supplied through lines 16, 18, 19 while exhausting line 13. Pressurizing line 18 opens valves 10, V1 whereby liquid exhausted from the cylinders 1, 8 passes through lines 9, 15 and 14 back into the cylinder 11a. Thus liquid from the cylinder 8 replenishes leakage from the cylinder 11a.