Torque Limiter Assembly With Automatic Dual-Torque Switching
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Solution Overview
Problem
Existing torque limiting apparatuses are inefficient in automatically switching between low and high torque modes based on resistance levels, leading to potential mechanical damage due to excessive torque, and require larger and more complex designs to achieve effective torque limitation.
Innovation Solution
A torque limiting assembly that utilizes a motion converter mechanism with helical protrusions and channels, a resilient biasing member, and an intermediate bush to automatically switch between low and high torque modes by transforming rotational forces into axial forces and back, with adjustable preloading to control the torque threshold, and incorporates a mechanism to prevent input shaft rotation relative to the casing in high torque mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a torsion bar is used to transmit torque and allow relative rotation during overload, then torque limitation is achieved, but the device becomes larger and more complex
Solution Approach 1:
The patent employs a dynamic switching mechanism that automatically transitions between low torque and high torque modes based on resistance levels. The motion converter mechanism converts rotational motion to linear motion and back, enabling automatic mode switching without complex external control systems. This dynamic adaptation resolves the contradiction by providing reliable torque limitation through a relatively simple, self-regulating mechanical structure.
Solution Approach 2:
The patent changes the torque transmission parameter dynamically by switching between two distinct torque modes (low torque and high torque). The resilient biasing member and motion converter mechanism enable this parameter change by adjusting the engagement state between components based on resistance levels, achieving effective torque limitation through parameter variation rather than complex continuous control.
2Productivity
If automatic mode switching is implemented, then torque control efficiency is improved, but the mechanism becomes more complex
Solution Approach 1:
The patent implements a self-service automatic switching mechanism where the system regulates its own torque transmission based on resistance levels. The motion converter mechanism and resilient biasing member work together to automatically detect resistance conditions and switch between torque modes without external intervention, improving torque control efficiency while keeping the mechanism relatively simple through self-regulation.
Solution Approach 2:
The patent incorporates implicit feedback through the resilient biasing member that responds to resistance levels. When resistance increases, the biasing member compresses and triggers the motion converter mechanism to switch modes. This feedback loop enables efficient automatic torque control by continuously monitoring resistance conditions and adjusting the torque transmission state accordingly.
3Volume of moving object
If backlash is minimized for compact design, then precision is improved, but the mechanism becomes more complex
Solution Approach 1:
The patent applies preliminary action through preloading the resilient biasing member before operation. This preloading establishes a predetermined torque threshold that triggers mode switching. By preparing the biasing member in advance with appropriate tension, the system achieves compact dimensions with minimized backlash while maintaining simple mechanism design through predetermined force application rather than complex real-time adjustment 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 efficient and automatic switching between low and high torque modes, reducing mechanical stress and allowing for compact design by minimizing backlash and utilizing adjustable preloading to control the torque threshold, thereby protecting mechanical equipment from overload.
Implementation Method 1
a resilient biasing member, preferably a spring, arranged to be compressed by relative rotation between the input shaft and the drive bush
Implementation Method 2
The motion converter mechanism may comprise a rotational-to-linear motion converter and a linear-to-rotational converter
Data Source
Figure 1
Figure 2A~2C
Figure 2D~3A
AI summary
A torque limiting assembly is disclosed comprising: an input shaft 4; an output shaft 6; a drive bush 10; a motion converter mechanism 25; a casing 48; and at least one engagement member 46 for engaging the casing 48. In a low torque mode, rotation of the input shaft 4 drives rotation of the drive bush 10, motion converter mechanism 25 and output shaft 6. In a high torque mode, rotation of the motion converter mechanism 25 relative to the output shaft 6 urges the motion converter mechanism 25 axially to drive rotation of the drive bush 10 relative to the input shaft 4. The engagement member 46 is coupled to both the drive bush 10 and the input shaft 4 such that when the drive bush 10 is rotated relative to the input shaft 4, the engagement member 46 is urged to engage the casing 48 so as to prevent or inhibit rotation of the input shaft 4 relative to the casing 48.