Reversible stepping actuator
First Claim
1. A reversible stepping actuator for producing a reversible incremental output rotation in response to a pulse input comprising:
- a drive gear;
a first ratchet wheel connected to the gear for driving the gear in a first sense of rotation;
a second ratchet wheel connected to the gear for driving the gear in a second sense of rotation opposite to the first sense of rotation;
a first drive pawl for engaging the first ratchet wheel and driving the first wheel in the first sense;
a second drive pawl for engaging the second ratchet wheel and driving the second wheel in the second sense;
a first locking pawl for engaging the first ratchet wheel and preventing rotation of the first wheel in the second sense;
a second locking pawl for engaging the second ratchet wheel and preventing rotation of the second wheel in the first sense;
means for maintaining both locking pawls in engagement with their respective ratchet wheels and both drive pawls out of engagement with their respective ratchet wheels when in a neutral position;
first actuator means for disengaging the second locking pawl from the second ratchet wheel and at about the same time engaging the first drive pawl with the first ratchet wheel; and
second actuator means for disengaging the first locking pawl from the first ratchet wheel and at about the same time engaging the second drive pawl with the second ratchet wheel.
6 Assignments
0 Petitions
Accused Products
Abstract
A high torque reversible stepping actuator for valves can drive in small increments in response to fluid pressue pulses. The stepping actuator has oppositely facing ratchet wheels on a common shaft linked to the stepping actuator output. A pair of operator means can drive the ratchet wheels in opposite directions. Each operator means comprises a fluid pressure actuator connected to a drive pawl for driving one of the ratchet wheels in one direction. A pair of locking pawls normally engage the ratchet wheels preventing rotation in either direction. The fluid pressure actuator disengages one of the locking pawls sequentially before engaging the drive pawl with the ratchet wheel, thereby permitting advance of the ratchet wheel. The other locking pawl remains engaged and prevents back drive of the ratchet wheels and stepping actuator due to elastic deformation of the drive train connecting the ratchet wheel with the valve or other mechanism being driven.
-
Citations
34 Claims
-
1. A reversible stepping actuator for producing a reversible incremental output rotation in response to a pulse input comprising:
-
a drive gear; a first ratchet wheel connected to the gear for driving the gear in a first sense of rotation; a second ratchet wheel connected to the gear for driving the gear in a second sense of rotation opposite to the first sense of rotation; a first drive pawl for engaging the first ratchet wheel and driving the first wheel in the first sense; a second drive pawl for engaging the second ratchet wheel and driving the second wheel in the second sense; a first locking pawl for engaging the first ratchet wheel and preventing rotation of the first wheel in the second sense; a second locking pawl for engaging the second ratchet wheel and preventing rotation of the second wheel in the first sense; means for maintaining both locking pawls in engagement with their respective ratchet wheels and both drive pawls out of engagement with their respective ratchet wheels when in a neutral position; first actuator means for disengaging the second locking pawl from the second ratchet wheel and at about the same time engaging the first drive pawl with the first ratchet wheel; and second actuator means for disengaging the first locking pawl from the first ratchet wheel and at about the same time engaging the second drive pawl with the second ratchet wheel. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. A reversible stepping actuator comprising:
-
a pair of interconnected ratchet wheels having teeth directed clockwise and counterclockwise respectively; means connected to the ratchet wheels for providing an output rotation in response to rotation of the ratchet wheels; and a pair of similar operator means for driving the ratchet wheels clockwise and counterclockwise respectively, such operator means comprising; a normally disengaged clockwise drive pawl; a counterclockwise locking pawl with the counterclockwise ratchet wheel for preventing back drive of the ratchet wheels clockwise; means for sequentially disengaging the counterclockwise locking pawl and engaging the clockwise drive pawl with the clockwise ratchet wheel for advancing the ratchet wheels clockwise; a normally disengaged counterclockwise drive pawl; a clockwise locking pawl with the clockwise ratchet wheel for preventing back drive of the ratchet wheels counterclockwise; and means for sequentially disengaging the clockwise locking pawl and engaging the counterclockwise drive pawl with the counterclockwise ratchet wheel for advancing the ratchet wheels counterclockwise. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16)
-
-
17. A reversible stepping actuator comprising:
-
a pair of fixed together coaxial ratchet wheels having ratchet teeth for driving clockwise and counterclockwise respectively; means for driving the ratchet wheels clockwise comprising; a clockwise driving pawl for driving the clockwise ratchet wheel; and a clockwise locking pawl for engaging the clockwise ratchet wheel for permitting rotation of the ratchet wheels clockwise and preventing rotation of the ratchet wheels counterclockwise; means for driving the ratchet wheels counterclockwise comprising; a counterclockwise drive pawl for driving the counterclockwise ratchet wheel; and a counterclockwise locking pawl for engaging the counterclockwise ratchet wheel for permitting rotation of the ratchet wheels counterclockwise and preventing rotation of the ratchet wheels clockwise; means for resiliently biasing the locking pawls towards engagement with their respective ratchet wheels; means for holding each drive pawl in a disengaged position out of engagement with its respective ratchet wheel; means for stroking the clockwise drive pawl from the disengaged position towards an engaged position in engagement with the clockwise ratchet wheel and retracting the counterclockwise locking pawl from engagement with the counterclockwise ratchet wheel for advancing the ratchet wheels one tooth spacing clockwise; and means for stroking the counterclockwise drive pawl from the disengaged position towards an engaged position in engagement with the counterclockwise ratchet wheel and retracting the clockwise locking pawl from engagement with the clockwise ratchet wheel for advancing the ratchet wheels one tooth spacing counterclockwise. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25)
-
-
26. A reversible stepping actuator for producing an incremental output rotation in response to a fluid pressure pulse input comprising:
-
a clockwise ratchet wheel; a counterclockwise ratchet wheel fixed coaxially to the clockwise ratchet wheel; a pair of similar operator means for rotating the ratchet wheels, such an operator means comprising; a drive pawl for engaging the clockwise ratchet wheel and driving the ratchet wheels in the clockwise direction; a locking pawl engaging the counterclockwise ratchet wheel and preventing rotation of the ratchet wheels in the clockwise direction; and reciprocatable fluid pressure actuator means for sequentially disengaging the locking pawl from the counterclockwise ratchet wheel and engaging the drive pawl with the clockwise ratchet wheel for rotating the ratchet wheels in the clockwise direction an incremental distance; and means for coupling the ratchet wheels to an output shaft for rotation of the output shaft. - View Dependent Claims (27, 28, 29)
-
-
30. A stepping actuator for producing a reversible output rotation in response to a fluid pressure pulse input comprising:
-
a pair of fluid pressure actuators for stroking between a retracted position and an extended position; a ratchet wheel having a first set of teeth forming a clockwise circumferential face and a second set of teeth forming a counterclockwise circumferential face offset axially from the clockwise face; a pair of opposed locking pawls mounted for scissoring on a common shaft parallel to the ratchet wheel axis, each locking pawl having a point for engaging a tooth on a respective one of the faces of the ratchet wheel, for preventing rotation of the ratchet wheel in opposite directions; means for resiliently biasing the locking pawls towards engagement of the points with the ratchet wheel; a pair of opposed drive pawls on opposite edges of the ratchet wheel, each drive pawl including a point for engaging a tooth on a respective one of the faces of the ratchet wheel; means for connecting each of the drive pawls to one of the actuators; means for resiliently biasing the drive pawls towards engagement with the ratchet wheel; guide means for holding each drive pawl out of engagement with the ratchet wheel when its connected actuator is in its retracted position and guiding the drive pawl through a ratchet advancing stroke as its connected actuator strokes from the retracted position toward the extended position; and means for retracting the point of such a locking pawl from engagement with the ratchet wheel in response to extension of such an actuator for permitting rotation of the ratchet wheel by the drive pawl connected to that actuator. - View Dependent Claims (31, 32, 33, 34)
-
Specification