Clamping Linear Actuator Spring Brake Mechanism
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Solution Overview
Problem
Existing electric linear actuators are not designed to clamp hard objects effectively, often resulting in damage to the actuator or the object, and they cannot maintain a grip without continuous power, unlike pneumatic cylinders.
Innovation Solution
A linear actuator with a housing, a shaft, and springs that compress to stop the motor and apply a brake, allowing for a strong grip on objects without the need for compressed air, using a limit switch to detect spring compression and shut off the motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the actuator proceeds rapidly toward the object and then slows down just before collision, then the object and actuator are protected from damage, but it requires knowing the exact size of the object and using a sophisticated controller to monitor current and shut down quickly
Solution Approach 1:
The spring mechanism automatically performs the function of detecting collision and shutting down the motor without requiring external sensors or complex control systems. The spring compresses upon collision, mechanically triggering the limit switch to stop the motor, making the system self-regulating and eliminating the need for sophisticated current monitoring controllers.
Solution Approach 2:
The patent replaces the electronic control system (current monitoring, sophisticated controller) with a simple mechanical spring-based system. The spring's physical compression directly triggers the limit switch, substituting complex electronic detection and control with a straightforward mechanical mechanism.
2Device complexity
If the actuator advances rapidly until collision occurs, then the structure is simple, but the motor overloads and the actuator fails after approximately 80,000 cycles
Solution Approach 1:
The spring is pre-positioned to compress upon collision, acting as a cushion that absorbs the impact energy before it can damage the motor or other components. This beforehand cushioning allows the actuator to withstand repeated collision cycles (80,000+ cycles) without mechanical failure or overheating.
3Reliability
If the motor is shut off after collision, then the motor is protected from overload, but the grip on the object loosens and the load could fall
Solution Approach 1:
The system dynamically transitions from motor-driven motion to spring-maintained position. During active operation, the motor provides controlled movement. Upon collision, the spring takes over to maintain gripping force, creating a dynamic system that adapts its force source based on operational state, ensuring both motor protection and grip stability.
4Speed
If a spring-actuated brake is applied to the motor, then the motor can be stopped, but if the load is jostled, it may fall because there is nothing to maintain the gripping force
Solution Approach 1:
The patent merges the braking function with the gripping force maintenance function into a single spring mechanism. The same spring that compresses to trigger the limit switch also maintains the gripping force after motor shutdown, eliminating the need for a separate brake system and ensuring load stability through the spring's continuous mechanical force.
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 efficient clamping and maintaining grip on objects without power consumption, similar to pneumatic actuators, but with improved reliability and reduced mechanical strain, suitable for applications like robot grippers and mobile vehicles.
Implementation Method 1
a second attachment point connected to the other of the housing or the distal end of the shaft by way of one or more springs
Implementation Method 2
springs that compress to stop the motor and apply a brake
Implementation Method 3
a motor that is operatively engaged with the shaft to drive movement of the shaft
Data Source
AI summary
A linear actuator having a housing, a shaft having a proximate end attached to the housing and a distal end which moves relative to the housing, a first attachment point on one of the housing or the distal end of the shaft, a second attachment point connected to the other of the housing or the distal end of the shaft by way of one or more springs, and a motor that is operatively engaged with the shaft to drive movement of the shaft. The linear actuator may be connected within any desired mechanism with at least two parts that move relative to one another, such as a mechanical gripper, by connecting one part to the first attachment point and the other part to the second attachment point.