Valve actuator
First Claim
1. A valve operator driven by a power source, comprising:
- a housinga worm gear within the housing coupled to the valve;
a drive shaft coupled to said power source including a worm portion which is capable of engaging the worm gear;
torque sensing means responsive to axial movement of said drive shaft, the torque sensing means including a pivotable support lever biased into a first position and having a bearing portion for engagement with the drive shaft, said pivotable support lever pivoted from its first position by axial movement of the drive shaft caused by excessive torque loading on the drive shaft to terminate delivery of power to the drive shaft;
disengagement means for disengaging the worm portion of the drive shaft from the worm gear, including a drive shaft support bracket attached to said housing for biased pivotal movement, said bracket having a bearing engaging the drive shaft while permitting rotational movement thereof, the support bracket pivotal to permit disengagement of the worm portion of the drive shaft from the worm gear, the disengagement means including manually operated means for pivoting the bracket; and
means for actuating a switch means responsive to movement of the valve to control the degree of opening or closing thereof, including a lead screw operatively connected to the drive shaft, a traveler threadably engaging the lead screw for movement parallel to the lead screw and engageable with said switch means and adjustable means for positioning the switch at positions parallel to the axis of the lead screw.
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Accused Products
Abstract
A valve operator utilizes a disconnectable worm gear arrangement to drive a valve spindle. An hand crank may be used to disengage the power-driven worm gear arrangement and to manually drive the valve spindle, if necessary, by pivoting a bracket holding the end of the worm shaft. The worm gear is self-locking so that reaction forces from the valve cannot move the worm gear. A torque-sensing lever, responsive to axial movement of a highly torqued drive shaft, pivots against the force of a biasing spring to operate a microswitch to cut off electrical power to the drive motor for the valve operator should the torque exceed a predetermined amount. Additional protection against torque overload is provided by an adjustable mechanical clutch which operates in the event of control element failure or misadjustments. One or more microswitches, adjustable in position, are engaged by a traveler which moves along a lead screw driven by a gear arrangement coupled to the valve spindle to control operation of the actuator. The worm shaft is pivotable away from its normal axis of operation by means of a splined universal coupling.
25 Citations
6 Claims
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1. A valve operator driven by a power source, comprising:
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a housing a worm gear within the housing coupled to the valve; a drive shaft coupled to said power source including a worm portion which is capable of engaging the worm gear; torque sensing means responsive to axial movement of said drive shaft, the torque sensing means including a pivotable support lever biased into a first position and having a bearing portion for engagement with the drive shaft, said pivotable support lever pivoted from its first position by axial movement of the drive shaft caused by excessive torque loading on the drive shaft to terminate delivery of power to the drive shaft; disengagement means for disengaging the worm portion of the drive shaft from the worm gear, including a drive shaft support bracket attached to said housing for biased pivotal movement, said bracket having a bearing engaging the drive shaft while permitting rotational movement thereof, the support bracket pivotal to permit disengagement of the worm portion of the drive shaft from the worm gear, the disengagement means including manually operated means for pivoting the bracket; and means for actuating a switch means responsive to movement of the valve to control the degree of opening or closing thereof, including a lead screw operatively connected to the drive shaft, a traveler threadably engaging the lead screw for movement parallel to the lead screw and engageable with said switch means and adjustable means for positioning the switch at positions parallel to the axis of the lead screw. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification