Wire Attachment Spool Calibration Mechanism

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Solution Overview

Problem

Existing wire attachments for sheathed wires in hydraulic systems require time-consuming calibration and are not easily recalibrated during operation, which complicates maintenance and efficiency.

Innovation Solution

A wire attachment design that includes a spool with a spring-loaded mechanism to maintain initial calibration, allowing radial pressure on the sheath for secure attachment without disturbing the axial position, and an external access point for the engagement member to simplify installation and prevent rotational movement of the spool.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the wire is fastened to a spool at a given distance from the end of the sheath requiring calibration by moving the sheath end forward or backwards, then the wire attachment can be calibrated progressively to compensate for wear and slacking, but the calibration process becomes time-consuming and complex

Engineering Contradiction:
Improvecalibration accuracyVSAvoidcalibration time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The spool is pre-positioned at a predetermined distance from the sheath end during manufacturing, eliminating the need for time-consuming field calibration. The sheath end is designed with a stop that automatically positions the wire end at the correct location on the spool, ensuring accurate calibration without requiring manual adjustment during installation or maintenance.

Inventive Principle:
Principle #10Preliminary action

2Ease of operation

If the spool is allowed to rotate freely inside the axial bore, then the spool can rotate to engage the wire, but the engagement member cannot be reliably accessed from outside the housing

Engineering Contradiction:
Improveengagement member accessibilityVSAvoidspool rotational stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The spool is pre-positioned and pre-oriented during assembly so that the engagement member automatically faces the aperture in the housing. A stop mechanism on the sheath end ensures the spool is positioned at the correct location and orientation, allowing reliable external access to the engagement member without requiring complex rotational adjustment mechanisms.

Inventive Principle:
Principle #10Preliminary action

3Strength

If a threaded sleeve is used to clamp the sheath, then the sheath can be securely fastened, but the calibration position is disturbed during attachment

Engineering Contradiction:
Improvesheath attachment securityVSAvoidaxial position accuracy
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The spool and sheath are pre-positioned at their correct relative distances during assembly before any clamping occurs. The stop on the sheath end ensures that when the threaded sleeve clamps the sheath, the wire end is already at the predetermined correct position on the spool, eliminating calibration disturbance. The clamping force is applied after positioning, not during positioning.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2076690B1Wire attachment
Publication Date: 2014.06.25 NORDHYDRAULIC AB
  • EP2076690B1 patent drawingFigure 1
  • EP2076690B1 patent drawingFigure 2~5
  • EP2076690B1 patent drawingFigure 3

AI summary

Wire attachment (1) for a sheathed wire (20) including a wire (21) and a sheath (22) coaxially surrounding the wire, the wire attachment (1) comprising: a housing (2); an axial bore (10) inside the housing including an opening (10a) adapted to receive the sheathed wire (20); a spool (5) slidably arranged inside the bore (10), the spool being adapted to receive the wire (21) and comprises an engagement member (6) for fixedly engaging the wire (21), such that any longitudinal movement of the wire (21) will be transmitted to the spool (5); a sheath attachment member (3) for fixing the sheath (22) to the wire attachment (1) inside the axial bore (10) at a distance from the receiving bore (10), such that the spool (5) and the wire (21) is free to move axially with respect to the sheath (22). Further, the sheath attachment member (3) is arranged to exert a substantially radial pressure onto the surface of the sheath (22), such that it may be attached essentially without disturbing the axial position of the sheath (22). The invention also relates to a method of attaching a sheathed wire (20).