| 摘要 |
A conveyor system comprises a conveyor drivable at variable speeds by a hydraulic motor which is controlled by a cam regulated flow control valve. Sensing means responsive to some condition on the conveyor requiring a change in speed (i.e., excessive accumulation of conveyed articles requiring conveyor slow-down) are connected to the cam on the flow control valve to effect a corresponding change in conveyor speed. The valve amplifies the relatively small fluid control signal therewithin to effect control of relatively high pressure fluid. The valve comprises a movable poppet whose position determines the rate of flow between a fluid inlet and a controlled fluid outlet port connected to the hydraulic motor, a movable piston for positioning the poppet, a movable shut-off member for regulating piston position by controlling fluid pressure applied to the piston from the fluid inlet, and an adjustable cam to establish the position of the shut-off member and thereby control fluid flow to the motor and control conveyor speed. The cam comprises a plurality of differently shaped cam segments, and is manually adjustable initially to enable the selection of a desired segment. The cam is movable by the sensing means across the range of the selected cam segment to provide fluid flow between zero and some maximum flow rate at the controlled fluid outlet port, rate of flow being determined by the position and the shape of the selected cam segment. The four cam segments, for example, enable flow rates between 0 to 4 gallons per minute (gpm), 0 to 5 gpm, 0 to 6 gpm, and so on, depending on the number and shape of segments on the cam surface.
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