Linear Actuator Failsafe Clutch Mechanism
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Solution Overview
Problem
Electric linear actuators often fail to return to a safe position when power is lost, relying on backup systems that can fail, have temperature limitations, and pose ignition hazards.
Innovation Solution
A failsafe apparatus with a spring and clutch mechanism that moves a stem to a predetermined position without electrical power, using a frame with moveable jaws and a solenoid to engage and disengage the stem, ensuring the actuator returns to a safe state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If backup power systems are used to drive the motor to move the stem to a failsafe position, then the stem can be moved to a safe position during power loss, but the backup power systems can fail without notice, have temperature limitations, and create ignition hazards
Solution Approach 1:
The patent replaces the electrical backup power system with a purely mechanical spring-loaded clutch mechanism. The spring is pre-loaded during normal operation and automatically engages to move the stem to the failsafe position when power is lost, eliminating all electrical components and associated ignition hazards from the failsafe system.
Solution Approach 2:
The invention extracts and removes the backup power system entirely, relying instead on the stored mechanical energy in the spring. This extraction eliminates the harmful factors (ignition hazards, temperature limitations) while maintaining the essential function of moving the stem to a failsafe position.
2Object-affected harmful factors
If a spring mechanism is used to move the stem to failsafe position without electrical power, then ignition hazards are eliminated, but the clutch mechanism adds complexity to the actuator system
Solution Approach 1:
The patent merges the clutch mechanism with the existing actuator stem and coupling interface. The clutch jaws engage directly with the stem, and the spring is integrated into the existing actuator housing, minimizing additional components and reducing overall system complexity despite adding the mechanical failsafe function.
3Reliability
If the jaws are moveably coupled to the frame to engage and disengage the stem, then the spring can effectively move the stem to failsafe position, but the moveable jaw mechanism increases device complexity
Solution Approach 1:
The clutch jaws are designed to be moveable rather than fixed, allowing them to dynamically engage and disengage from the stem. This dynamic capability enables the spring to effectively move the stem to the failsafe position by releasing the mechanical constraint, while the moveability is achieved through simple pivoting motion rather than complex actuation mechanisms.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The apparatus effectively moves the stem to a failsafe position without electrical power, eliminating the need for unreliable backup systems and reducing ignition hazards, ensuring device stability and safety.
Implementation Method 1
A spring is to urge the first stem toward a failsafe position. The spring moves the first stem toward the failsafe position when the jaws disengage the other one of the first stem or the second stem.
Data Source
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AI summary
Failsafe apparatus for use with linear actuators are disclosed. A failsafe apparatus for use with a linear actuator (102) includes a spring (124) to urge a first stem (106) of a device (108) to be operated by the linear actuator toward a failsafe position and a clutch (104) to operatively couple a second stem (110) of the linear actuator (102) to the first stem (106). The clutch (104) includes a frame (112) coupled to one of the first stem or the second stem and jaws (114,116) moveably coupled to the frame. The jaws are to engage the other one of the first stem or the second stem to enable the linear actuator to operate the device and to disengage the other one of the first stem or the second stem to enable the spring to move the first stem toward the failsafe position.