Torque Wrench with Segmented Scale and Helical Drive

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Solution Overview

Problem

Existing wrenches fail to provide precise measurement of torque due to difficulties in aligning scales with pointers, poor precision in setting unit's place values, and inconvenient multi-dial operation.

Innovation Solution

A wrench design featuring a shank with a longitudinal slot, a handle with a magnifying lens, a torque-setting device with a movable pin, and a torque-measuring device including a helical groove and scale, allowing precise torque measurement with clear observation through a collar window.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a dial with scale and pointer is used to display torque values, then the structure is simple, but the measurement precision is insufficient due to alignment difficulties

Engineering Contradiction:
Improvestructure simplicityVSAvoidtorque value precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The scale is segmented into multiple independent digits (hundreds, tens, units places) displayed separately on the dial. Each digit can be independently adjusted and read, eliminating the alignment problems of traditional continuous scales while improving measurement precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The traditional mechanical pointer alignment system is replaced with a digital display system using springs and gears to move individual digit indicators. This substitution eliminates alignment errors inherent in pointer-scale systems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If traditional dial scales are used to set torque values, then the device is easy to manufacture, but the precision in setting unit's place digits is poor

Engineering Contradiction:
Improvemanufacturing easeVSAvoiddigit setting precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The torque setting mechanism is segmented into independent digit positions (hundreds, tens, units). Each digit has its own adjustment mechanism with clear numerical markings, allowing precise setting of unit's place digits while maintaining ease of manufacture through modular design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each digit position on the scale has specialized local features including magnified numerical markings and distinct visual indicators. This local enhancement of quality at critical reading points improves precision without complicating the overall manufacturing process.

Inventive Principle:
Principle #3Local quality

3Measurement precision

If multiple dials are used to set maximum torque value, then the measurement precision can be improved, but the device complexity and ease of operation deteriorate

Engineering Contradiction:
Improvetorque value precisionVSAvoidnumber of dials
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Multiple digit indicators (hundreds, tens, units) are merged into a single integrated dial assembly rather than separate dials. This consolidation maintains the precision of multi-digit display while reducing overall device complexity and improving ease of operation.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single dial assembly serves multiple functions: displaying hundreds digit, tens digit, and units digit simultaneously, as well as providing torque setting capability. This multi-functionality eliminates the need for multiple separate dials while maintaining measurement precision.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Illumination intensity

If the scale is exposed for observation, then the readability is good, but the scale is vulnerable to damage or contamination

Engineering Contradiction:
Improvescale readabilityVSAvoidscale protection
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

A transparent protective cover is introduced as an intermediary element between the scale and the external environment. This cover protects the scale from damage and contamination while allowing light to pass through, maintaining good readability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

A thin transparent protective film or cover is used to shield the scale. This thin protective layer maintains optical clarity for readability while providing protection against physical damage and contamination.

Inventive Principle:
Principle #30Flexible shells and thin films

Data Source

PatentEP2425934B1Wrench equipped with a precise torque-measuring device
Publication Date: 2013.06.05 MATATAKITOYO TOOL
  • EP2425934B1 patent drawingFigure 1
  • EP2425934B1 patent drawingFigure 2
  • EP2425934B1 patent drawingFigure 3

AI summary

A wrench (10) includes a shank (11) including a slot (14) defined therein longitudinally, a handle (13) attached to an end of the shank (11), a head (12), a torque assembly (20) for connecting the head (12) to another end of the shank (11), a torque-setting device (30)and a torque-measuring device (50). The torque-setting device (30) includes a knob inserted in the handle (13) and a pin (32) movable in and along the slot (14) as the knob is spun. The torque-measuring device (50) includes a measurement sleeve (60) and a collar (80). The measurement sleeve (60) is rotationally located around the shank (11) and includes a helical groove (61) defined in an internal side and a scale provided on an external side. A portion of the pin (32) is movably inserted in the helical groove (61) so that the measurement sleeve (60) is spun as the pin (32) is moved in and along the slot (14). The collar (80) is located around the shank (11) and includes a window (51) through which the scale (64) is observable.