Roller Wrench Latching Geometry for Higher Torque Engagement
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Solution Overview
Problem
Conventional roller wrenches are ineffective due to large included angles between latching surfaces and the peripheral wall, resulting in rollers being unable to move far enough to effectively latch, and thus fail to provide a reliable disengaging-engaging function and offer low torque.
Innovation Solution
The roller wrench design features a driving member with regular polygonal sides, each with concave latching surfaces that gradually recess inwardly, forming a small included angle with the central area, allowing rollers to move further and effectively latch with the latching surfaces and peripheral wall.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the included angle between latching surfaces and peripheral wall is large, then the structure is simpler, but the rollers cannot move far enough to effectively latch
Solution Approach 1:
The patent changes the geometric parameters of the latching surfaces by creating concave portions that gradually recess inwardly from the edges toward the center of each side. This modifies the included angle between the latching surfaces and the peripheral wall from a large angle to a smaller angle, allowing rollers to move a longer distance along the latching surface before disengaging, thereby improving latching effectiveness.
2Length of moving object
If the gap between latching surfaces and peripheral wall reduces rapidly, then the structure is more compact, but the rollers can only move a small distance
Solution Approach 1:
The patent modifies the gap progression by creating concave latching surfaces that gradually recess inwardly. This changes the rate at which the gap between latching surfaces and peripheral wall reduces, transforming it from a rapid reduction to a gradual reduction, thereby extending the roller movement distance while maintaining chamber compactness.
3Strength
If the conventional latching surface design is used, then the manufacturing is easier, but the torque capacity is low
Solution Approach 1:
The patent changes the geometric parameters of the latching surfaces by introducing concave portions that gradually recess inwardly from the edges toward the center. This creates a smaller included angle between the latching surfaces and the peripheral wall, allowing rollers to travel a longer distance and engage more effectively, thereby increasing the torque capacity of the wrench.
Data Source
AI summary
A roller wrench including a body with a circular chamber; a driving member with multiple sides capable of rotating in the chamber; a plurality of rollers installed in the chamber and located between a side of the driving member and a peripheral wall of the chamber; and a reversing knob capable of driving the rollers to move. Each of the sides of the driving member has a central area, a concave latching surface is respectively provided on two sides of the central area, and a concave state of each of the latching surfaces is gradually concaved inwardly from an inner side to an outer side. When each of the rollers is located on one edge of each of the sides, a peripheral surface of the roller contacts with the latching surface and the peripheral wall of the chamber; the body, rollers and driving member are latched with one another.