Torque Screwdriver Freewheel Mechanism
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Solution Overview
Problem
Existing torque screwdrivers with mechanical ratchet mechanisms experience return resistance when reversing, making them ineffective for applications requiring low tightening torques or loose screw connections, and they lack a resistance-free return mechanism.
Innovation Solution
A torque screwdriver with a freewheel mechanism that includes a clutch system with angled teeth and a compression spring, allowing for resistance-free return and adjustable release torque, and a switchable freewheel mechanism for one-way torque transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical ratchet mechanism is used for torque transmission, then torque can be transmitted in one direction, but return resistance occurs when reversing direction
Solution Approach 1:
The patent extracts the harmful return resistance characteristic from the ratchet mechanism by introducing a freewheel mechanism that allows free rotation in the return direction. The freewheel mechanism is coupled with the ratchet mechanism, enabling the ratchet to maintain its torque transmission function while the freewheel eliminates the return resistance by allowing the input shaft to rotate freely when torque is released.
Solution Approach 2:
The freewheel mechanism acts as an intermediary between the ratchet mechanism and the input shaft. It mediates the conflict between reliable torque transmission (provided by the ratchet) and ease of return (enabled by free rotation), allowing both functions to coexist by directing torque transmission through the ratchet while permitting free return movement through the freewheel.
2Reliability
If a ratchet mechanism with return resistance is used, then torque transmission is reliable, but low tightening torques cannot be applied effectively
Solution Approach 1:
The patent removes the return resistance from the system by incorporating a freewheel mechanism that allows the input shaft to rotate freely when torque is released. This extraction of the harmful return resistance property enables the application of low tightening torques without the opposing force that would otherwise prevent effective tightening of loose screw connections.
3Adaptability or versatility
If a reversible ratchet mechanism is used, then torque transmission in both directions is possible, but return resistance varies and is never completely eliminated
Solution Approach 1:
The patent completely eliminates return resistance by using a freewheel mechanism instead of a reversible ratchet. The freewheel allows free rotation in the return direction while maintaining controlled torque transmission in the tightening direction, thereby extracting the harmful return resistance property entirely from the system while preserving bidirectional functionality.
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 effective tightening of screws with low torques and loose connections without return resistance, ensuring precise torque application and easy re-engagement.
Implementation Method 1
The first clutch element is biased by a compression spring
Implementation Method 2
The clamping element is pressed against the flat surface of the shaft section and against the inner circumferential surface of the outer ring
Data Source
Figure 1~2
Figure 3~7
Figure 8~10
AI summary
The invention relates to a torque screwdriver (1) which has a handle (2) and a display (3) for a torque which has been set, and has an output (4). A setting device (5) for setting a torque and a torque mechanism (17) are arranged in the handle (2), the torque mechanism (17) comprising a drive shaft (18) for transmitting a torque and a release mechanism (23) for interrupting a transmission of torque when a torque which has been set is reached. The drive shaft (18) and the output (4) are coupled via a freewheel mechanism (33).