Work Tool Lock Mechanism for Inertia Braking
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Solution Overview
Problem
Existing work tools fail to properly stop the rotation of tool accessories after the motor is turned off, leading to continued rotation due to inertia, which can cause issues during tool replacement and operation.
Innovation Solution
A work tool design incorporating a motor, tool-mounting part, rotary shaft, rotating member, switch, and lock mechanism, where the operation member moves between ON and OFF positions to allow or lock the rotating member, applying a braking force to the rotary shaft, ensuring the tool accessory stops rotation after motor shutdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lock mechanism is used to lock rotation during tool replacement, then tool replacement safety is improved, but the mechanism cannot stop the tool accessory from continuing to rotate by inertia after motor shutdown
Solution Approach 1:
The lock mechanism is designed to dynamically change its state based on the operation member position. When the operation member is in the ON position, the lock mechanism allows rotation for normal operation. When the operation member moves to the OFF position, the lock mechanism automatically locks the rotating member to stop inertia rotation. This dynamic adaptation resolves the contradiction by making the same mechanism serve both tool replacement safety and rotation stopping functions.
Solution Approach 2:
The lock mechanism is designed to perform multiple functions: (1) locking rotation during tool replacement when the operation member is in the OFF position, and (2) stopping inertia rotation after motor shutdown by locking the rotating member. By making the lock mechanism universal, the patent resolves the contradiction between tool replacement safety and rotation stopping capability, as both functions are achieved by the same mechanism responding to different operational states.
2Speed
If the lock mechanism locks the rotating member immediately when the operation member moves to OFF position, then rotation stopping is improved, but the torque transmission from rotating member to rotary shaft is interrupted
Solution Approach 1:
The lock mechanism is designed to lock the rotating member as a preliminary action immediately when the operation member moves to the OFF position. This preliminary locking action stops the rotating member's rotation first, and then the torque is gradually transmitted to the rotary shaft through the frictional engagement between the friction surfaces. This sequence resolves the contradiction by prioritizing rotation stopping while still enabling torque transmission.
Solution Approach 2:
The frictional engagement between the friction surfaces of the rotating member and rotary shaft acts as a cushioning mechanism. When the lock mechanism locks the rotating member, the friction between the surfaces gradually transmits the torque to the rotary shaft, preventing sudden shock or damage. This beforehand cushioning resolves the contradiction by enabling both rapid rotation stopping and smooth torque transmission.
3Power
If friction surfaces are provided between the rotating member and rotary shaft, then torque transmission is improved, but the structure becomes more complex
Solution Approach 1:
The friction surfaces for torque transmission are merged into the existing structure of the rotating member and rotary shaft. The rotating member is designed with a friction surface that directly engages with the friction surface of the rotary shaft, eliminating the need for separate torque transmission components. This merging resolves the contradiction by providing effective torque transmission while maintaining structural simplicity.
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
Effectively prevents the tool accessory from continuing to rotate by inertia after the motor is stopped, enhancing safety and operational efficiency during tool replacement and operation.
Implementation Method 1
the rotating member applies a braking force to the rotary shaft by action of transmitting the torque
Data Source
AI summary
A work tool includes a motor, a tool-mounting part, a rotary shaft, a rotating member, a switch, an operation member and a lock mechanism. The rotating member is held rotatably around a rotation axis of the rotary shaft and configured to transmit torque to and from the rotary shaft while being allowed to rotate relative to the rotary shaft. The rotating member is configured to rotate together with the rotary shaft by action of transmitting the torque when the operation member is moved from the OFF position to the ON position and the lock mechanism allows the rotating member to rotate, and configured to apply a braking force to the rotary shaft by action of transmitting the torque when the operation member is moved from the ON position to the OFF position and the lock mechanism non-rotatably locks the rotating member.