Linear Actuator Emergency Release Clutch Mechanism
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Solution Overview
Problem
Conventional linear actuators used for hospital beds cannot quickly lower the beds during emergencies, as they rely solely on motor-driven movement.
Innovation Solution
A linear actuator design incorporating a clutch member system with motors, actuator members, a base, clutch driver, and a pulling handle, allowing for selective connection or disconnection of the motor to the actuator member, enabling rapid release and quick lowering of the bed by pulling the handle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a conventional motor-driven linear actuator structure is used, then the structure is simple and reliable, but the bed cannot be quickly lowered during emergencies
Solution Approach 1:
The patent applies the dynamics principle by introducing a clutch mechanism that allows the actuator system to switch between two operational states: a locked state during normal operation where the motor controls movement, and an unlocked state during emergencies where gravity can quickly lower the bed. The clutch member with clutch claws and engagement surfaces enables this dynamic state change, allowing rapid transition from controlled movement to free gravitational descent without requiring complex additional braking or control systems.
Solution Approach 2:
The clutch mechanism serves as an intermediary element between the motor-driven screw rod and the pushing linkage. This intermediary component (comprising the clutch member, clutch claws, and engagement surfaces) selectively transmits or blocks the motor's driving force to the actuator block. During emergencies, the clutch disengages, allowing the pushing linkage to move freely under gravitational force, thus mediating between the motor system and the gravitational force to achieve rapid bed lowering.
2Loss of time
If a clutch mechanism is added to enable quick release, then the lowering speed is improved, but the device complexity increases
Solution Approach 1:
The actuator system is segmented into distinct functional components: the motor-driven screw rod mechanism for controlled movement, the clutch mechanism for selective engagement/disengagement, and the pushing linkage for force transmission. The clutch member itself is segmented into multiple clutch claws that can independently engage with corresponding surfaces on the actuator block. This segmentation allows the quick-release function to be added as a modular component rather than requiring a complete redesign of the entire actuator system.
Solution Approach 2:
The clutch claws are pre-positioned and spring-loaded to automatically engage with the clutch engagement surfaces during normal operation, establishing the locked state before any emergency occurs. This preliminary engagement action ensures that the system is ready for rapid transition to emergency mode. When the emergency release mechanism is activated, the pre-positioned clutch claws simply need to be pushed away from the engagement surfaces, allowing immediate gravitational descent without requiring complex active disengagement 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
Enables rapid lowering of hospital beds during emergencies by allowing the pushing linkage to quickly return, effectively addressing the limitations of conventional linear actuators.
Implementation Method 1
The clutch member (400) includes a worm gear (410), a transmitting claw (420), and a clutch ring (430). The worm gear (410) is engaged with the motor (200).
Implementation Method 2
A cam (720) in contact against the flange (510) is formed on an end of the pulling handle (700), and a shaft (710) is inserted through the end. The shaft (710) is inserted through the guiding slot (520) to connect the clutch driver (600).
Implementation Method 3
The actuator members (300) include a screw rod (310), an actuator block (320), and a pushing linkage (330). One end of the screw rod (310) is pivotally disposed in a vertical manner on the vertical faces (111, 112), and the end is enclosed in a bearing (311) so as to be axially rotatable. The other end of the screw rod (310) is threadedly connected to the actuator block (320).
Implementation Method 4
The clutch ring (430) is disposed outside the worm gear (410) to enclose the same, each sliding key (431) is engaged into a respective corresponding one of the sliding grooves (411), and thereby the clutch ring (430) is slidable in a longitudinal direction of the worm gear (410).
Data Source
AI summary
A linear actuator includes a housing, motors, actuator members, clutch members, a base, a clutch driver, and a pulling handle. The motors are disposed in the housing. The actuator members are respectively disposed in the housing and corresponding to a respective one of the motors. Each clutch member is connected between a respective one of the motors and a respective corresponding one of the actuator members. The base is disposed on an outer surface of the housing, a flange is disposed on an outer surface of the base, and a guiding slot is formed on the base. The clutch driver is in the base and connected to each of the clutch members. A cam contacting against the flange is formed on an end of the pulling handle, and a shaft is inserted through the end. The shaft is inserted through the guiding slot to connect the clutch driver.