Spacer Collar With Rotating Balls for Low-Friction Tube Insertion

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Solution Overview

Problem

Existing spacer collars for underground tubes do not effectively reduce friction and require high pulling forces during insertion, lack self-cleaning capabilities, and provide insufficient stability and resistance to external loads.

Innovation Solution

A spacer collar with rotatable elements, such as balls or convex surfaces, that reduce friction and enhance stability by allowing smoother sliding, combined with a scraper effect for impurity removal and enhanced material resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If traditional spacer collars are used to maintain spacing between inner and outer tubes, then electrical insulation and spacing are ensured, but friction between tubes increases and high pulling forces are required during insertion

Engineering Contradiction:
Improvepulling forceVSAvoidspacing maintenance
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The patent applies spherical elements (balls) as rotatable components on the spacer collar. These spherical elements reduce friction by converting sliding friction into rolling friction, allowing the inner tube to slide more easily into the outer tube while the collar maintains its spacing function. The curved surface of the balls enables smooth rotation and reduces the pulling force required during insertion.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The spacer collar incorporates rotatable elements that can dynamically adjust during the insertion process. The balls are capable of rotating as the tube is pulled through, allowing the collar to adapt to the motion and reduce friction dynamically rather than relying on static contact surfaces. This dynamic capability maintains spacing while reducing the force required.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If spacer collars are secured to the outer surface of the inner tube, then spacing is maintained, but the collars create obstacles to smooth insertion and increase friction

Engineering Contradiction:
Improveinsertion smoothnessVSAvoidpulling force
Core Design Contradiction:
Ease of operationVSForce

Solution Approach 1:

The spherical elements on the spacer collar provide a curved contact surface that reduces friction during insertion. The balls can rotate freely, creating a smoother interaction between the collar and the tube surface, thereby reducing the pulling force needed while maintaining the spacing function.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The rotatable balls act as intermediary elements between the spacer collar and the tube surface. They mediate the interaction by converting direct sliding contact into rolling contact, which reduces friction and makes insertion smoother while the collar itself remains secured to maintain spacing.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If conventional spacer collars are used, then spacing is maintained, but they lack self-cleaning capabilities and accumulate impurities that reduce efficiency

Engineering Contradiction:
Improvesupport efficiencyVSAvoidimpurity accumulation
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The rotatable spherical elements on the spacer collar perform a self-cleaning function. As the balls rotate during tube insertion, they scrape against the tube surface and collect impurities, automatically removing contaminants without external intervention. This self-service mechanism maintains the efficiency of the spacer collar throughout the insertion process.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The dynamic rotation of the spherical elements enables the self-cleaning action. The rotating balls continuously contact the tube surface, scraping off impurities as they move. This dynamic motion allows the collar to maintain its support efficiency by automatically removing contaminants that would otherwise accumulate and reduce performance.

Inventive Principle:
Principle #15Dynamics

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

Reduces the pulling force required for insertion, ensures stable and efficient tube placement, maintains electrical insulation, and provides resistance to corrosion and thermal shocks while facilitating easy installation.

Implementation Method 1

A spacer collar with rotatable elements, such as balls or convex surfaces, that reduce friction and enhance stability by allowing smoother sliding

Methodology Applied
Scientific EffectRolling friction: Friction

Implementation Method 2

The special shape of the housing of the ball has a scraper effect, which exerts a self-cleaning action as it allows eliminating the impurities collected during the sliding step

Methodology Applied
Scientific EffectAbrasion: Abrasion

Data Source

PatentEP4555245B1A spacer collar for reducing friction between tubes
Publication Date: 2026.04.22 RACI
  • EP4555245B1 patent drawingFigure 1~2
  • EP4555245B1 patent drawingFigure 3~4
  • EP4555245B1 patent drawingFigure 5~6

AI summary

A spacer collar (1 ) made of an annular-shaped plastic material comprises projections (2) protruding from the surface thereof and each projection contains a plastic ball (3) capable of rotating about the respective rotation axis C arranged in the transverse direction to the longitudinal axis A of the inner tube (6), which is inserted in a covering tube (8). The rotating balls (3) allow easy sliding of the tube inside the covering tube.