Variable Crankshaft Ratchet Mechanism for Torque-Based Stroke Adjustment
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Solution Overview
Problem
Existing powered ratchet tools lack a mechanism to change the extent of each rotational stroke based on the applied torque, leading to inefficiencies in torque application and stroke length.
Innovation Solution
A powered ratchet tool with a crankshaft assembly that includes a variable crank radius, an eccentric pin, and cam members that adjust the position of the eccentric pin relative to the crankshaft axis, allowing for a change in the extent of each rotational stroke based on torque levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed crank radius is used in the ratchet mechanism, then the structure is simple, but the stroke length cannot be adjusted based on torque levels
Solution Approach 1:
The patent applies the dynamics principle by making the crank radius variable rather than fixed. The eccentric pin can move between different positions (first position for first stroke length, second position for second stroke length) to dynamically adjust the crank radius according to torque requirements. This allows the system to adapt its mechanical characteristics based on operating conditions while maintaining a relatively simple overall structure.
2Productivity
If the eccentric pin position is fixed, then the manufacturing is simple, but the torque application efficiency varies
Solution Approach 1:
The patent applies parameter changes by varying the position of the eccentric pin along the crankshaft. The eccentric pin can be positioned at a first position to define a first crank radius for optimal torque application at lower torque levels, or moved to a second position to define a second crank radius for optimal torque application at higher torque levels. This parameter adjustment optimizes torque application efficiency across different operating conditions.
3Adaptability or versatility
If a single stroke length is used, then the mechanism is simple, but the operational versatility is limited
Solution Approach 1:
The patent applies universality by designing the crankshaft assembly to perform multiple functions through a single variable mechanism. The same crankshaft assembly with movable eccentric pin can provide different stroke lengths (first stroke length for low torque, second stroke length for high torque) to handle various operational requirements. This multi-functionality allows one mechanism to serve multiple purposes without requiring separate dedicated mechanisms for different stroke lengths.
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 tool efficiently adjusts the stroke length and torque application based on the torque level, enhancing operational efficiency and versatility.
Implementation Method 1
The crankshaft has an eccentric pin offset from the first axis. The eccentric pin is configured to travel along a first rotational path during operation at a first torque and a second rotational path during operation at a second torque greater than the first torque.
Data Source
AI summary
A powered ratchet tool includes a housing and a motor disposed within the housing. The motor has an output shaft rotatable about a first axis. The powered ratchet tool further includes a ratchet mechanism supported by the housing and operably coupled to the output shaft to be driven by the motor. The ratchet mechanism has a crankshaft assembly defining a variable crank radius configured to change an extent of each rotational stroke of the ratchet mechanism. Moreover, the powered ratchet tool includes an output drive operably coupled to the ratchet mechanism to be rotated about a second axis perpendicular to the first axis.