Pulling device for flexible conduit tubing

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Solution Overview

Problem

The flexible nature of PEX™ tubing, stored on spools, causes it to form curvature, making it difficult to insert straight through wall and floor cavities, leading to misalignment and installation challenges.

Innovation Solution

A pipe pulling device with an expansion sleeve and tapered nut system that grips the tubing, combined with a modular tip body and optional wear collars, allows for controlled insertion and alignment through building structures, using a combination of frictional gripping and adjustable lengths to manage the tubing's curvature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If PEX tubing is stored on spools to maintain flexibility and reduce shipping costs, then flexibility and storage efficiency are improved, but the tubing forms curvature that makes insertion through wall cavities difficult

Engineering Contradiction:

ImproveflexibilityVSAvoidinsertion through wall cavities

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent applies preliminary action by pre-attaching a pulling device with a gripping mechanism to the end of the PEX tubing before insertion attempts. This gripping device is prepared in advance to counteract the curvature issue, allowing the installer to maintain control and alignment of the curved tubing during the insertion process through wall and floor cavities.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary pulling device that acts as a mediator between the installer and the curved PEX tubing. This device includes a gripping mechanism that attaches to the tubing end and provides a straight reference point, allowing the installer to guide the curved tubing through cavities by controlling the intermediary device rather than directly manipulating the curved tubing itself.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If the tubing is made flexible to eliminate fittings and enable continuous runs, then installation speed and fewer connections are improved, but alignment and line-up through cavities become extremely difficult

Engineering Contradiction:

Improveinstallation speedVSAvoidalignment through cavities

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent replaces the mechanical system of direct manual manipulation of flexible tubing with a mechanical gripping device that provides rigid control. The pulling device with its gripping mechanism substitutes the installer's direct handling, providing a stable reference point that enables precise alignment through cavities while maintaining the benefits of flexible tubing installation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If the tubing remains in its natural curved state from spool storage, then storage efficiency and flexibility are maintained, but the end is pointed away from the target hole making line-up impossible

Engineering Contradiction:

Improvestorage efficiencyVSAvoidline-up accuracy

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent applies inversion by attaching the pulling device to the end of the tubing in reverse to the natural curvature direction. The gripping mechanism is positioned at the end of the tubing where the curvature causes misalignment, and the device's straight shaft extends in the opposite direction of the curve, creating a reference point that points toward the target hole rather than away from it.

Inventive Principle:

Principle #13The other way round (Inversion)

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

Enables efficient and precise insertion of PEX™ tubing through enclosed spaces by maintaining a firm grip and allowing for adjustments to accommodate the tubing's natural curvature, reducing installation difficulties and improving alignment accuracy.

Implementation Method 1

grip the tubing by expansion

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 2

tapered nut system that grips the tubing

Methodology Applied

Scientific EffectPoisson's Effect: Poisson's Effect

Data Source

PatentUS10578233B2Pulling device for flexible conduit tubing

Publication Date: 2020.03.03 CURRAN PATRICK GEORGE

AI summary

A pipe pulling device guides extruded plastic conduit tubing through a building structure. The device has a fastener body including a main shaft supporting a resilient expansion sleeve thereon that can be inserted into an open end of the tubing. A nut is threaded onto the main shaft for axially compressing the expansion sleeve between the nut and a fastener head at the inner end of the main shaft to radially expand the sleeve within the tubing and frictionally grip the fastener body relative to the tubing. The nut is tapered outwardly and supports an elongate, rigid tip body extending longitudinally outward from the tubing to guide insertion of the tubing through cavities in the building structure. Various accessories can be secured to the nut or the tip body to assist insertion of the pipe pulling device through different building structures.