Fluid operated stepping motor

Claim 2

A fluid operated stepping motor comprising: a source of supply pressure; a source of drain pressure; an output member, having a cyclic edge profile, bidirectionally movable between a plurality of discrete positions; three fluid operated actuators arranged adjacent the output member for advancing the output member by successive engagement with the profile thereof, each actuator having a fully extended position and a retracted position, a selected actuator being in the fully extended position and the other actuators being in retracted positions in the discrete positions of the output member; power valve means to connect the actuators to the sources of supply pressure and drain pressure; logic means adapted to receive bi-directional, digital, command signal pulses to contRol the power valve means such that supply pressure is directed to the selected actuator while drain pressure is directed to the other actuators and such that supply pressure is continuously directed to the selected actuator after termination of the signal pulse to drive the output member to a discrete position and provide a positive position lock thereafter; means to communicate the signal pulses to the logic means; and a discrete feedback control operatively connected to the logic means for generating a feedback signal thereto as the output member assumes a discrete position such that an actuator different from the previously selected actuator is advanced from the retracted position to the extended position by a succeeding signal pulse to drive the output member to an adjacent discrete position.

Claim 3

A fluid operated stepping motor, as defined in claim 1, wherein the feedback control comprises: a plurality of permanent magnets mounted on the output member; and a plurality of magnetosensitive switches positioned adjacent the output member and actuable thereby.

Claim 4

A fluid operated stepping motor, as defined in claim 1, wherein said feedback control comprises: a plurality of sequencing conduits connected to the actuators for generating fluid feedback signals to the logic circuit.

Claim 5

A fluid operated stepping motor, as defined in claim 1, wherein the output member comprises an output shaft carrying a rotor.

Claim 6

A fluid operated stepping motor, as defined in claim 1, further including: bias means, operable upon an increase in supply pressure after a depletion thereof, to drive the output member from a position intermediate two adjacent discrete positions to a discrete position so that proper sequencing of the actuators may be affected by a subsequent signal pulse.

Claim 7

A fluid operated stepping motor comprising: a source of supply pressure; a source of drain pressure; a rotor, having a cyclic edge profile, bi-directionally movable between a plurality of discrete positions; three groups of fluid operated actuators arranged adjacent the output member for successively advancing the output member by engagement with the profile thereof, each group comprising a plurality of actuators positionable in unison between corresponding positions, each actuator having a fully extended position and a retracted position, the actuators of a selected group being in extended positions and the actuators of the other groups being in retracted positions in the discrete positions of the rotor; power valve means to connect the groups to the sources of supply pressure and drain pressure; logic means adapted to receive bi-directional, digital, command signal pulses to control the power valve means such that supply pressure is directed to the selected group while drain pressure is directed to the other groups and such that supply pressure is continuously directed to the selected group after termination of the signal pulse to drive the rotor to a discrete position and provide a positive position lock thereafter; means to communicate the signal pulses to the logic means; and a discrete feedback control operatively connected to the logic means for generating a feedback signal thereto as the rotor assumes a discrete position such that the actuators of a group different from the previously selected group are advanced from the retracted positions to the extended positions by a succeeding signal pulse to drive the rotor to an adjacent discrete position.

Claim 8

A fluid operated stepping motor comprising: a source of supply pressure; a source of drain pressure; a rotor, having a cyclic edge profile, bi-directionally movable between a plurality of discrete positions; three groups of fluid operated actuators arranged adjacent the output member for successively advancing the output member by engagement with the profile thereof, each group comprising a plurality of actuators positionable in unison between corresponding positions, each actuator having a fully extended position and a retracted position, the actuators of a selected group being in extended positions and the actuators of the other groups being in retracted positions in the discrete positions of the rotor; power valve means to connect the groups to the sources of supply pressure and drain pressure; logic means adapted to receive bi-directional, digital, command signal pulses to control the power valve means such that supply pressure is directed to the selected group while drain pressure is directed to the other groups and such that supply pressure is continuously directed to the selected group after termination of the signal pulse to drive the rotor to a discrete position and provide a positive position lock thereafter; means to communicate the signal pulses to the logic means; and a discrete feedback control operatively connected to the logic means for generating a feedback signal thereto as the rotor assumes a discrete position such that the actuators of a group different from the previously selected group are advanced from the retracted positions to the extended positions by a succeeding signal pulse to drive the rotor to an adjacent discrete position.

Claim 9

A fluid operated stepping motor, as defined in claim 6, wherein the feedback control comprises: a plurality of permanent magnets mounted on the output member; and a plurality of magnetosensitive switches positioned adjacent the output member and actuable thereby.

Claim 10

A fluid operated stepping motor, as defined in claim 6, wherein the feedback control comprises: a plurality of sequencing conduits connected to the actuators for generating fluid feedback signals to the loGic circuit.

Claim 11

A fluid operated stepping motor, as defined in claim 6, wherein both sides of the rotor have a cyclic edge profile and wherein half of the actuators are arranged on one side of the rotor and half of the actuators are arranged on the other side of the rotor such that each actuator is parallel to the shaft and in axial alignment with another actuator of the same group.

Claim 12

A fluid operated stepping motor comprising: a rotor having a plurality of pairs of converging ramps formed on at least one side thereof; a plurality of actuators positioned adjacent the rotor parallel to the axis of the rotor for selectively engaging the ramps to rotate the rotor; a logic circuit operatively connected to the actuators for selectively directing pressurized fluid thereto; a discrete feedback control operatively connected to the logic circuit for generating a feedback signal thereto representative of a discrete position of the rotor; and the feedback control comprising: a plurality of permanent magnets mounted on the rotor; and a plurality of magnetosensitive switches positioned adjacent the rotor and actuable thereby.

Claim 13

A fluid operated stepping motor comprising: a rotor having a plurality of pairs of converging ramps formed on at least one side thereof; a plurality of actuators positioned adjacent the rotor parallel to the axis of the rotor for selectively engaging the ramps to rotate the rotor; a logic circuit operatively connected to the actuators for selectively directing pressurized fluid thereto; a discrete feedback control operatively connected to the logic circuit for generating a feedback signal thereto representative of a discrete position of the rotor; and the feedback control comprising: a plurality of permanent magnets mounted on the rotor; and a plurality of magnetosensitive switches positioned adjacent the rotor and actuable thereby.

Claim 14

A fluid operated stepping motor comprising: a rotor having a plurality of pairs of converging ramps formed on at least one side thereof; a plurality of actuators positioned adjacent the rotor parallel to the axis of the rotor; a logic circuit operatively connected to the actuators for selectively directing pressurized fluid thereto; a discrete feedback control operatively connected to the logic circuit for generating a feedback signal thereto representative of a discrete position of the rotor; and the feedback control comprising: a plurality of sequencing conduits connected to the actuators for generating fluid feedback signals.

Claim 15

A fluid operated stepping motor comprising: a rotor having a plurality of pairs of converging ramps formed on at least one side thereof; a plurality of actuators positioned adjacent the rotor parallel to the axis of the rotor; a logic circuit operatively connected to the actuators for selectively directing pressurized fluid thereto; a discrete feedback control operatively connected to the logic circuit for generating a feedback signal thereto representative of a discrete position of the rotor; and the feedback control comprising: a plurality of sequencing conduits connected to the actuators for generating fluid feedback signals.