Adjustable Wrench Constraint Structure for High-Torque Jaw Stability

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Solution Overview

Problem

The existing adjustable wrenches suffer from increased fit clearance between the worm wheel and worm when applying torque, leading to reduced maximum torque application and potential workpiece slippage due to deformation of the adjustable jaw.

Innovation Solution

An adjustable wrench with a constraint structure that includes clamping grooves and reinforcement features to prevent the side walls from opening, maintaining the fit clearance between the worm wheel and worm, thereby increasing the maximum torque applied.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the adjustable wrench applies torque to the workpiece, then the workpiece is clamped and torqued, but the fit clearance between the worm wheel and worm increases due to deformation of the adjustable jaw

Engineering Contradiction:
Improvemaximum torque applicationVSAvoidfit clearance maintenance
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The constraint structure is pre-installed on the adjustable jaw before torque application. It proactively prevents the side walls from opening during torque application, rather than correcting the problem after deformation occurs. This preliminary constraint maintains the fit clearance between the worm wheel and worm even under high torque loads.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The constraint structure applies a counteracting force to prevent the opening of side walls before the deformation can occur. By providing this preliminary anti-action, the structure counteracts the tendency of the adjustable jaw to deform under torque, thereby maintaining the precise fit between the worm wheel and worm.

Inventive Principle:
Principle #9Preliminary anti-action

2Ease of operation

If the adjustable jaw deforms under torque, then the side walls tilt outward, but the fit clearance increases and the adjustable jaw displaces from its initial position

Engineering Contradiction:
Improveadjustable jaw positioningVSAvoidfit clearance between worm wheel and worm
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The constraint structure is pre-installed on the adjustable jaw before torque application. It proactively prevents the side walls from opening during torque application, rather than correcting the problem after deformation occurs. This preliminary constraint maintains the fit clearance between the worm wheel and worm even under high torque loads.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The constraint structure acts as an intermediary element between the adjustable jaw and the external torque load. It mediates the stress distribution and prevents the transmission of deforming forces to the critical fit interface between the worm wheel and worm, thereby maintaining positioning precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Power

If the side walls open under torque, then the worm wheel deviates from the worm, but the maximum torque that can be applied decreases

Engineering Contradiction:
Improvemaximum torque applicationVSAvoidconstraint structure
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The constraint structure is divided into multiple functional segments: constraint portions that prevent side wall opening, reinforcement portions that strengthen the adjustable jaw, and connection portions that integrate these features. This segmentation allows each component to perform its specific function efficiently while keeping the overall structure manageable and effective.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The constraint structure merges multiple functions into a single integrated component: it combines the constraint function (preventing side wall opening), the reinforcement function (strengthening the adjustable jaw), and the positioning function (maintaining worm wheel alignment). This merging reduces the number of separate components needed while achieving multiple objectives simultaneously.

Inventive Principle:
Principle #5Merging (Combining)

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 constraint structure effectively prevents the side walls from opening, ensuring the adjustable wrench maintains the fit clearance and increases the maximum torque applied to the workpiece by 2-2.5 times that of the American standard.

Implementation Method 1

the constraint structure is configured to prevent the two opposite side walls from opening when applying a torque to the workpiece

Methodology Applied
Scientific EffectMechanical constraint: Mechanical Force

Implementation Method 2

The worm wheel and the worm have a self-locking capability. When a workpiece is initially clamped by turning the worm wheel, the adjustable jaw is locked at an initial clamping position

Methodology Applied
Scientific EffectSelf-locking capability: Friction

Data Source

PatentEP4684916A1Adjustable wrench
Publication Date: 2026.01.28 HANGZHOU GREAT STAR IND CO LTD
  • EP4684916A1 patent drawingFigure 1
  • EP4684916A1 patent drawingFigure 2
  • EP4684916A1 patent drawingFigure 3~4

AI summary

An adjustable wrench, comprising: a handle (100); and a fixed jaw (200) and an adjustable jaw (400) that are arranged at one end of the handle (100); wherein an abutment position of the fixed jaw (200) and the handle (100) is provided with a track slot (500), and two sides of the track slot (500) extend to form two opposite side walls (600); the adjustable jaw (400) comprises a shaft portion (401), a neck portion (402), and a clamping portion; the shaft portion (401) is accommodated in the track slot (500) and is configured to move along the track slot (500); the clamping portion protrudes out of the track slot (500) and is configured to cooperate with the fixed jaw (200) to clamp a workpiece; and the neck portion (402) is located between the two opposite side walls (600); wherein the adjustable wrench further comprises a constraint structure, and the constraint structure is configured to prevent the two opposite side walls (600) from opening when applying a torque to the workpiece clamped between the adjustable jaw (400) and the fixed jaw (200).