Adjustable Wrench Worm Gear Stability via Local Quality

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Solution Overview

Problem

Conventional adjustable wrenches with biasing elements face instability of the worm gear in the engaged position, which can be improved without making the wrench bulkier or harder to manipulate.

Innovation Solution

The adjustable wrench incorporates a biasing element with compression spring and balls that urge the worm gear toward the engaged position, utilizing mirror-symmetric support surfaces with varying angles of incline to stabilize the worm gear efficiently while allowing easy manipulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the angle of incline of the planar surfaces is increased to improve worm gear stability, then the stability of the worm gear in the engaged position is improved, but the cavity becomes much larger making the wrench bulky and manipulation becomes harder

Engineering Contradiction:
Improvestability of the worm gearVSAvoidcavity volume
Core Design Contradiction:
Stability of the object's compositionVSVolume of stationary object

Solution Approach 1:

The patent applies local quality by creating two distinct regions with different incline angles within the same support structure. The first region (first planar surface) has a first angle of incline optimized for stabilizing the worm gear in the engaged position, while the second region (second planar surface) has a second angle of incline optimized for easy manipulation and disengagement. This allows each region to have locally optimized properties without compromising the overall structure.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The support surfaces are segmented into multiple planar regions with different incline angles. Instead of using a single uniform surface, the patent divides the support structure into at least two distinct planar surfaces, each with its own optimized angle of incline. This segmentation allows the system to achieve multiple functions (stability and ease of manipulation) simultaneously without requiring a larger cavity.

Inventive Principle:
Principle #1Segmentation

2Stability of the object's composition

If the angle of incline of the planar surfaces is increased to improve worm gear stability, then the stability of the worm gear in the engaged position is improved, but the force needed to move the worm gear increases making manipulation harder

Engineering Contradiction:
Improvestability of the worm gearVSAvoidforce to move worm gear
Core Design Contradiction:
Stability of the object's compositionVSForce

Solution Approach 1:

The patent applies local quality by creating two distinct regions with different incline angles within the same support structure. The first region (first planar surface) has a first angle of incline optimized for stabilizing the worm gear in the engaged position, while the second region (second planar surface) has a second angle of incline optimized for easy manipulation and disengagement. This allows each region to have locally optimized properties without compromising the overall structure.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The support surfaces are segmented into multiple planar regions with different incline angles. Instead of using a single uniform surface, the patent divides the support structure into at least two distinct planar surfaces, each with its own optimized angle of incline. This segmentation allows the system to achieve multiple functions (stability and ease of manipulation) simultaneously without requiring a larger cavity.

Inventive Principle:
Principle #1Segmentation

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 design enhances the stability of the worm gear in the engaged position while maintaining ease of use and preventing bulkiness, allowing precise adjustments with reduced manual effort.

Implementation Method 1

a biasing element configured to urge the worm gear toward the engaged position by applying forces on both support surfaces

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3597368B1Adjustable wrench comprising releasable worm gear
Publication Date: 2021.03.17 STANLEY BLACK & DECKER MEA FZE
  • EP3597368B1 patent drawingFigure 1
  • EP3597368B1 patent drawingFigure 2
  • EP3597368B1 patent drawingFigure 3~4

AI summary

The invention deals with an adjustable wrench comprising: a first jaw (8) and a second jaw (10) movable relative to the first jaw (8), wherein the second jaw (10) comprises a rack (12), a worm gear (18) movable into an engaged position wherein the worm gear (18) engages the rack (12) and wherein a rotation of the worm gear (18) causes the second jaw (10) to move relative to the first jaw (8), and into a disengaged position wherein the worm gear (18) does not engage the rack (12), a body (2) defining two surfaces, one of the surfaces comprising a first portion (14a) and a second portion (14b), the other surface comprising a third portion (16a) and a fourth portion (16b), the first portion (14a), the second portion (14b), the third portion (16a) and the fourth portion (16b) comprising a first point (140a), a second point (140b), a third point (160a) and a fourth point (160b) respectively, a biasing element (20) configured to urge the worm gear (18) toward the engaged position by applying forces on both surfaces, the biasing element (20) simultaneously contacting the first point (140a) and the third point (160a) when the worm gear (18) is in a position comprised between the engaged position and an intermediate position, and simultaneously contacting the second point (140b) and the fourth point (160b) when the worm gear (18) is in a position comprised between the intermediate position and the disengaged position, wherein the angle of incline (α) of the first portion (14a) at the first point (140a) relative to the third portion (16a) at the third point (160a) is greater than the angle of incline (β) of the second portion (14b) at the second point (140b) relative to the fourth portion (16b) at the fourth point (160b).