Lockable Torque Wrench Pawl Mechanism
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Solution Overview
Problem
Conventional wrenches with torque-setting mechanisms often fail to reliably maintain the set torque value due to accidental knob rotation, excessive translation, or ineffective detent mechanisms, leading to inconsistent and potentially damaging torque application.
Innovation Solution
A lockable torque-setting mechanism featuring a sleeve, body, pawl, and lever, where the lever moves between positions to engage or disengage the pawl's teeth with the sleeve's teeth, ensuring secure locking and adjustment of the torque setting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spring-biased detent is used to keep the knob connected to the handle, then the knob should remain secured, but the detent mechanism proves ineffective and the knob can still be accidentally rotated or removed
Solution Approach 1:
A pawl member is introduced as an intermediary component between the knob and handle. The pawl engages with teeth on both the knob and handle to provide a positive mechanical lock, preventing accidental rotation or separation without requiring complex spring-biased detent mechanisms.
Solution Approach 2:
The locking function is segmented into distinct components: the pawl member for engagement, teeth on the knob for locking, and teeth on the handle for anchoring. This segmentation allows each component to perform its specific function effectively, improving reliability while maintaining simplicity.
2Reliability
If the handle is made with adequate length to keep the knob connected, then the knob should remain secured, but the long handle becomes unreliable
Solution Approach 1:
The pawl member serves as an intermediary locking component that enables secure connection between the knob and handle without requiring excessive handle length. The pawl's engagement with teeth on both components provides a reliable mechanical lock within a compact structure.
3Adaptability or versatility
If the knob is allowed to translate relative to the handle for torque adjustment, then torque setting is flexible, but the knob can be excessively translated and removed from the handle
Solution Approach 1:
The pawl member acts as an intermediary that permits controlled translation of the knob for torque adjustment while preventing excessive translation or removal. The engagement with teeth on both the knob and handle creates a ratchet-like mechanism that allows one-way movement while maintaining secure connection.
4Reliability
If a locking mechanism with pawl and lever is implemented, then accidental rotation is prevented, but the device complexity increases
Solution Approach 1:
The essential locking function is extracted and implemented through a simple pawl-tooth engagement mechanism. By focusing on the core locking requirement and implementing it through a straightforward pawl member that engages with teeth on the knob and handle, the design achieves reliability without unnecessary complexity.
Solution Approach 2:
The pawl member automatically engages with the teeth on the knob and handle through its own geometry and movement. The lever provides mechanical advantage to move the pawl into engagement, but once engaged, the mechanism maintains itself through the interlocking teeth without requiring additional active components or complex control systems.
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 mechanism provides a reliable and consistent torque setting, preventing accidental rotation and ensuring accurate torque application, thereby protecting workpieces from damage.
Implementation Method 1
The lever includes an end for pressing the pawl and another end pivotally connected to the body. The lever is movable in the cavity of the body between a first position to press a first portion of the pawl to engage the teeth of the pawl with the teeth of the sleeve and a second position to press a second portion of the pawl to disengage the teeth of the pawl from the teeth of the sleeve.
Data Source
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AI summary
A locking mechanism includes a sleeve, a body, a pawl and a lever. The sleeve is non-movably connected to a grip and formed with teeth. The body is non-movably connected to a knob, partially inserted in the sleeve, and includes a recess in communication with a cavity. The pawl is movably inserted in the recess and formed with teeth. The lever includes an end for pressing the pawl and another end pivotally connected to the body. The lever is movable in the cavity of the body between a first position to press a first portion of the pawl to engage the teeth of the pawl with the teeth of the sleeve and a second position to press a second portion of the pawl to disengage the teeth of the pawl from the teeth of the sleeve.