Torque Limiter Rotation Control Mechanism for Power Tools
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Solution Overview
Problem
Existing rotary fastening tools with torque limiters experience unexpected rotation of the driver body when the torque limiter is actuated, causing the user's hand to move in the tightening direction due to the instantaneous elimination of reaction force, leading to reduced ease of use.
Innovation Solution
A rotation control mechanism is introduced between the tool body and the tip-end rotating member, which locks the tool body and tip-end rotating member together during tightening operations, preventing rotation of the tool body and supporting the user's tightening force, while disabling this locking function during loosening operations to allow smooth mode switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a torque limiter is provided between the input side and the output side to interrupt torque transmission when torque reaches a set value, then the torque limiting function is improved, but the driver body unexpectedly rotates in the tightening direction when the torque limiter is actuated
Solution Approach 1:
A rotation control mechanism is introduced as an intermediary component between the motor unit and the fastening unit. This mechanism includes a rotation control member that selectively couples the input side and output side, allowing torque transmission during tightening operations while preventing unexpected rotation of the driver body when the torque limiter actuates. The rotation control member acts as a mediator that maintains stability without interfering with the torque limiting function.
2Ease of operation
If the rotation control mechanism locks the tool body to the tip-end rotating member during tightening operations, then the tool body rotation is prevented, but the mechanism complexity increases
Solution Approach 1:
The rotation control mechanism employs dynamic characteristics through a rotation control member that can selectively change its coupling state. During tightening operations, the member couples the input and output sides to prevent tool body rotation. During loosening operations, the member decouples to allow free rotation. This dynamic switching capability provides the desired stability when needed while avoiding unnecessary complexity through simple state-dependent behavior.
3Adaptability or versatility
If the rotation control mechanism is disabled during loosening operations by reverse rotation, then the loosening function is improved, but additional control mechanisms are required
Solution Approach 1:
The rotation control mechanism utilizes reverse rotation (loosening operations) to automatically disable the locking function that prevents tool body rotation during tightening. By inverting the operational state through reverse rotation direction, the mechanism naturally transitions from a locked state to an unlocked state, allowing the tool body to rotate freely during loosening without requiring additional control mechanisms or switches.
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 rotation control mechanism effectively prevents the tool body from rotating during tightening, maintaining user control and enhancing operational ease by supporting the user's force with the fixed tip-end rotating member, and automatically disabling the locking function for loosening operations without additional steps.
Implementation Method 1
a rotation control mechanism is provided between the motor unit and the fastening unit, which includes an elastic member that biases the rotation control member toward the actuated position
Data Source
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AI summary
It is an object of the invention to provide an effective technique for avoiding the influence of reaction during tightening operation in the rotary fastening tool. Representative rotary fastening tool includes a tool body, a motor housed within the tool body, a driving-side rotating member that is rotationally driven by the motor, a driven-side rotating member that is disposed coaxially with the driving-side rotating member, a tip-end side rotating member that is disposed coaxially with the driven-side rotating member and rotationally driven via the driven-side rotating member, the tip-end side rotating member driving a tool bit to perform a tightening operation and a rotation control mechanism that allows the tip-end side rotating member to rotate in the tightening direction during the tightening operation of the tool bit, wherein, when the tip-end side rotating member is fixed to a workpiece with the tool bit during the tightening operation and when torque transmission from the driving-side rotating member to the driven-side rotating member is interrupted, the rotation control mechanism locks the tip-end side rotating member and the tool body together against rotation with respect to each other to prevent the tool body from rotating in the tightening direction.