Linear actuator having manual override and locking mechanism

A locking mechanism for a motor driven linear actuator comprising:

• a motor;
• a gear train;
• an output pinion driven by the motor through the gear train;
• an output rack drivably coupled to the output pinion to translate rotation of the output pinion to linear translation of the output rack;
• a segment gear head having a toothed portion and a smooth portion on a face thereof, the toothed portion configured to engage a gear in the gear train, the segment gear head being positioned in relation to the gear such that rotation of the segment gear head between a locked position and an unlocked position results in engagement of the toothed portion with the gear in the locked position and disengagement of the toothed portion in the unlocked position, the segment gear head further defining a slot therethrough adapted to accommodate a stop pin therein, the slot being positioned in the segment gear head such that the stop pin abuts against a first end of the slot in the unlocked position and against a second end of the slot in the locked position;
• a reset lock spring operably coupled to the segment gear head to bias the segment gear head to the unlocked position;
• and
• a user interface coupled to the segment gear head to rotate the segment gear head between the locked and the unlocked positions.

A spring return, motor driven linear actuator for driving a flow control device to an actuated position under power and to a fail-safe position upon loss of power, the actuator comprising:

• a motor;
• a speed reducing, torque multiplying gear train drivingly coupled to an output of the motor;
• an output pinion drivingly coupled to the gear train, the output pinion being driven in a first rotary direction by the motor;
• an output rack drivingly coupled to the output pinion, the output rack being driven in a first linear direction by the output pinion under influence of the motor;
• a spring return mechanism including a clock spring coupled to the gear train, the clock spring being wound upon energization of the motor driving the output pinion in the first rotary direction, the clock spring unwinding upon motor de-energization to drive the output pinion through the drive train in a second rotary direction to thereby linearly translate the output rack in a second linear direction;
• a manual override mechanism having a first user accessible interface, the manual override mechanism operating in conjunction with the spring return mechanism to allow manual positioning of the output pinion and of the output rack, and winding of the clock spring;
• and
• a manual locking mechanism having a second user accessible interface, the manual locking mechanism engaging the gear train to prevent rotation of the output pinion in the second rotary direction and to prevent linear translation of the output rack in the second linear direction.