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Description
Pump 1 delivers fluid through flow-control valve 2 and directional valve 3 to the right end of cylinder 4, moving piston 5 and table 9, rigidly attached to the piston rod, to the left. From the left end of cylinder 4, fluid is discharged through valve 3 and flow-control valve 2 to the tank. At the end of the table stroke, pin a , mounted on the table, turns reversing lever 6 counterclockwise about fixed axis A. At this, tie-rod 13, linked to lever 6 and with slot f linked to the spool of valve 3, shifts the spool to the left. Owing to slot f in the tie-rod, lever 6 does not at first shift the spool of valve 3, but, with its prismatic lug, turns lever 7. When the apex of the lug of lever 6 passes the apex of the lug on lever 7, lever 6 is thrown over by spring 8, shifting the spool of valve 3 to the left. Then fluid is delivered to the left end of cylinder 4, moving piston 5 and table 9 to the right. The amount of fluid passing through flow-control valve 2 is regulated by spool 10 which is held by a spring with its stem head d against a cam rigidly attached to lever 11. Lever 11 serves to set the required table speed. Spool 10 throttles the fluid in the delivery line and in the discharge line. The clear opening can be varied by turning lever 11. At the end of the table stroke, one cam dog b engages the roller of bell-crank lever 12, turning about fixed axis B, and moves spool 10 to the right, reducing the table speed at the end of its stroke. This provides for smooth valve action. $4201$CHP,Dr$
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