Polygonal Torque Screwdriver Calibration Device

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Solution Overview

Problem

Existing screw calibration devices face issues with measurement uncertainty due to coupling clearances and bounces, especially with impact screwers, and require high assembly torque, which can lead to transducer overload and deformation.

Innovation Solution

A test device with a polygonal seat and clamp-type tightening mechanism that uses cup springs to simulate increased resisting torque and a torsion shaft with extensometer torque sensors, eliminating clearances and allowing for easy simulator replacement without excessive strain on the transducer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a threaded coupling with two or more threads is used to eliminate clearances, then measurement precision is improved, but the assembly torque becomes excessively high which can overload and deform the transducer

Engineering Contradiction:

Improvemeasurement precisionVSAvoidtransducer strength

Core Design Contradiction:

Measurement precisionVSStrength

Solution Approach 1:

The coupling mechanism is divided into two independent parts: a polygonal insertion portion that provides precise positioning without clearance, and a separate tightening mechanism (screw or clamp) that applies minimal assembly torque. This segmentation allows the positioning function and tightening function to be decoupled, eliminating the need for high-thread-count couplings that overload the transducer.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The polygonal seat acts as an intermediary element between the simulator and transducer. It provides precise angular positioning and clearance-free coupling through its geometric shape, while the separate tightening mechanism (screw or clamp) applies only the necessary minimal torque to secure the connection without transmitting excessive strain to the transducer.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If a threaded coupling is used to eliminate clearances, then measurement precision is improved, but device complexity increases due to multiple threads and assembly requirements

Engineering Contradiction:

Improvemeasurement precisionVSAvoidcoupling complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The coupling system is segmented into a simple polygonal insertion portion and a separate tightening element. This eliminates the complexity of multi-threaded couplings while maintaining clearance-free operation. The polygonal shape alone provides precise positioning, and the simple screw or clamp provides securing, reducing overall device complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of using thread complexity to eliminate clearance, the invention inverts the approach by using geometric shape (polygonal cross-section) to achieve clearance-free coupling. The polygonal insertion portion fits precisely into the matching seat, eliminating clearance without requiring complex threading.

Inventive Principle:

Principle #13The other way round (Inversion)

3Reliability

If high assembly torque is applied to secure the simulator, then connection reliability is improved, but the transducer may be permanently deformed or overloaded

Engineering Contradiction:

Improveconnection reliabilityVSAvoidtransducer strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The coupling and tightening functions are segmented into separate elements. The polygonal insertion portion provides immediate secure connection through geometric interference fit, while the separate screw or clamp provides additional securing with controlled, minimal torque. This ensures connection reliability without subjecting the transducer to excessive torque that could cause permanent deformation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The polygonal seat serves as an intermediary that distributes and manages the connection forces. It provides precise geometric engagement that secures the simulator reliably, while the separate tightening mechanism (screw or clamp) applies only the minimal necessary torque to maintain the connection without overloading the transducer.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

This solution provides reliable and repeatable torque measurements while preventing transducer overload during assembly and disassembly, ensuring accurate and efficient calibration without interference from bounces or clearance issues.

Implementation Method 1

a torsion shaft with extensometer torque sensors

Methodology Applied

Scientific EffectExtensometer measurement:

Implementation Method 2

a torsion shaft with extensometer torque sensors

Methodology Applied

Scientific EffectTorsion:

Implementation Method 3

uses cup springs to simulate increased resisting torque

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2350597B1Device for calibrating torque screw drivers with replaceable elements

Publication Date: 2018.05.23 ATLAS COPCO IND TECHNIQUE AB INTELLECTUAL PROPERTY DEPARTMENT

Figure 1~2

AI summary

A test device for screwers, comprises a transducer (11) having a head (28) with a seat (19) for receiving the coupling end (13) of an adapter or joint simulator (12, 12'). The coupling end (13) is made with a side wall (21, 21') polygonally- fashioned in order to be received in the seat (19), achieved in a complementary polygonal manner. The head (28) can be tightened as a clamp in order to releasably lock, in the seat (19), the coupling end (13) of the adapter or joint simulator.