Cable Traction Sleeve With Integrated Sliding Tube Dirt Sealing

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Solution Overview

Problem

Cable pull units in dirty environments face impaired function due to increased wear and friction, as well as potential corrosion, when dirt enters the annular space between the pull cable and casing, and existing solutions with additional sliding tubes increase manufacturing effort and frictional resistance.

Innovation Solution

A cable pull unit design featuring a sliding tube with a ring tulip expansion section and axial projection, where the sliding tube is monolithic with the projection, providing increased protection against dirt and moisture while maintaining low axial friction and high wear resistance, and is secured in a form-fitting manner within the support sleeve and tension end cap.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a sliding tube with axial projection is provided to protect against dirt ingress, then protection against contaminants is improved, but manufacturing effort and device complexity increase due to additional protective tubes

Engineering Contradiction:
Improveprotection against dirt ingressVSAvoiddevice complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The protective function and the sliding tube function are merged into a single monolithic component. The sliding tube includes an integrated axial projection that extends beyond the support sleeve end, eliminating the need for a separate protective tube while maintaining protection against contaminant ingress.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The sliding tube is designed to perform multiple functions simultaneously: it provides low-friction guidance for the pull cable, acts as a seal against contaminants, and its axial projection serves as both a protective barrier and a positioning element within the support sleeve.

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

2Object-affected harmful factors

If a sliding tube with axial projection is provided to protect against dirt ingress, then protection against contaminants is improved, but frictional resistance and wear increase at the joint between sliding tube and protective tube

Engineering Contradiction:
Improveprotection against dirt ingressVSAvoidwear resistance
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

By merging the protective tube and sliding tube into a single monolithic component, the interface joint between these two components is eliminated, thereby eliminating the source of frictional resistance and wear that would occur at their connection point.

Inventive Principle:
Principle #5Merging (Combining)

3Object-affected harmful factors

If additional sliding tubes are arranged as protective tubes, then protection against dirt ingress is improved, but manufacturing effort increases

Engineering Contradiction:
Improveprotection against dirt ingressVSAvoidmanufacturing effort
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The protective tube and sliding tube are merged into a single monolithic component that can be manufactured as one piece, eliminating the need for separate manufacturing processes and assembly steps required for multiple components.

Inventive Principle:
Principle #5Merging (Combining)

4Stability of the object's composition

If the sliding tube is secured with a conical expansion, then axial fixation is achieved, but friction and wear increase at the conical interface

Engineering Contradiction:
Improveaxial fixationVSAvoidwear resistance
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The axial fixation is achieved through a localized ring tuft structure with specific geometric features (conical expansion and axial projection) that provide secure positioning without creating extensive friction surfaces along the entire sliding tube length.

Inventive Principle:
Principle #3Local quality

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 design enhances axial load capacity, reduces friction and wear, simplifies production, and provides reliable protection against environmental influences without the need for additional components, improving operational behavior and service life.

Implementation Method 1

a sliding tube (23) arranged concentrically within the support shell (21), which in sliding contact encloses the pull cable (10) at least in sections

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

The sliding tube (23) has an annular tuft (40) which is spaced axially from a sliding tube end (23.3)

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentEP4071373B1Cable traction unit
Publication Date: 2024.01.10 SZW PROPHET GMBH
  • EP4071373B1 patent drawingFigure 1~2
  • EP4071373B1 patent drawingFigure 3

AI summary

The invention relates to a cable pull unit comprising a pull cable (10), a pull sleeve (20), and a pull end cap (30), wherein the pull cable (10) is longitudinally extended, flexible, and dimensionally stable, and is arranged at least sectionally in the pull sleeve (20) and is axially displaceable relative to the pull sleeve (20), wherein the pull sleeve (20) is longitudinally extended, flexible, and dimensionally stable and comprises a support sleeve (21), a sheath (22), and a sliding tube (23), wherein the support sleeve (21) is configured to receive and guide the pull cable (10), wherein the sliding tube (23) is arranged concentrically in the support sleeve (21), is in sliding contact with the pull cable (10), and has an axial sliding tube projection (23.1) towards a support sleeve end (21.1), wherein the sliding tube has an annular tuft (40), wherein the annular tuft (40) extends axially to a Slide tube end (23.3) is spaced apart, and has a proximal axial ring surface (41) and a distal axial ring surface (42), wherein the proximal axial ring surface (41) is axially supported on a support sleeve counter-ring surface (21.2), and wherein the pull end cap (30) at least partially encloses the sliding tube projection (23.1) and has a pull end cap counter-ring surface (30.1) on which the distal axial ring surface (42) is axially supported.