Linear Actuator Buffer Mechanism for Medical Bed Safety
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Solution Overview
Problem
Conventional linear actuators used in medical beds face issues with complex structures and high manufacturing costs due to the need for additional pneumatic rods for buffer functions, which often fail to absorb impact forces effectively during rapid drops, potentially harming patients.
Innovation Solution
A linear actuator design incorporating a gearbox, motor structure, lead screw, telescopic tube, quick release mechanism, and a buffer mechanism with a coil spring and limit rings to absorb impact forces, where the buffer mechanism is integrated on the external periphery of the lead screw between the nut and gearbox, enhancing axial bearing capacity and preventing deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pneumatic rod is installed next to the linear actuator to provide buffer function, then the buffer effect is improved, but the structure becomes more complicated and manufacturing cost increases
Solution Approach 1:
The buffer mechanism is integrated into the lead screw assembly by sheathing the coil spring buffer on the external periphery of the lead screw, combining the buffer function with the existing linear actuator structure rather than adding a separate pneumatic rod system
Solution Approach 2:
The lead screw assembly serves dual functions: both as the primary transmission mechanism and as the housing for the buffer mechanism, allowing one component to perform multiple functions and eliminate the need for additional dedicated buffer components
2Reliability
If a pneumatic rod is installed to provide buffer function, then the buffer capacity is improved, but the manufacturing cost increases
Solution Approach 1:
The coil spring buffer mechanism uses simple, inexpensive mechanical components (coil spring, limit rings, retaining ring) instead of costly pneumatic rods, providing effective buffer function at lower manufacturing cost
Solution Approach 2:
The buffer mechanism replicates the essential buffer function of pneumatic rods using a different, more cost-effective mechanical approach with coil springs and limit rings integrated into the lead screw assembly
3Reliability
If a pneumatic rod is used for buffering, then the buffer function is provided, but the impact force exceeds the load bearing capacity and causes damage
Solution Approach 1:
The coil spring buffer is pre-installed within the lead screw assembly to provide cushioning before impact occurs, with the spring designed to absorb impact forces that exceed normal operating loads
Solution Approach 2:
The buffer mechanism uses the elastic properties of the coil spring to dynamically change the stiffness parameter during impact, providing soft cushioning during normal operation and absorbing excessive impact forces during rapid drops
4Device complexity
If the buffer mechanism is integrated on the lead screw, then the structure complexity is reduced, but the space for buffer components is limited
Solution Approach 1:
The coil spring buffer mechanism is nested within the external periphery of the lead screw, with the spring, limit rings, and retaining ring arranged in a compact nested configuration that fits within the existing lead screw assembly dimensions
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 integrated buffer mechanism effectively absorbs impact forces during rapid drops, providing enhanced protection for patients by using a coil spring with limit rings to manage axial movement and prevent damage, thus improving safety and reducing structural complexity and costs.
Implementation Method 1
a coil spring made by rolling a plate provides a relatively greater axial bearing force to bear various different loads
Implementation Method 2
the telescopic tube has a nut screwed and transmitted with the lead screw
Data Source
AI summary
A linear actuator includes a gearbox, a motor structure, a lead screw, a telescopic tube, a quick release mechanism and a buffer mechanism. The motor structure is connected to the gearbox. The lead screw has a part inside the gearbox and the other part outside. The telescopic tube has a nut screwed with the lead screw. The quick release mechanism inside the gearbox is coupled to a cylindrical coupling member and a worm gear. The cylindrical coupling member is rotated with the lead screw, and the worm gear is driven by the motor structure to clutch the cylindrical coupling member. The buffer mechanism is installed at the external periphery of the lead screw and between the nut and gearbox for absorbing impact forces.