Reversible stepping actuator

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.

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.

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.

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.