Telescopic Pole Assembly Braking Mechanism

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing telescopic pole assemblies for working tools like hedge trimmers and chainsaws lack a reliable braking mechanism that provides consistent control over the sliding motion, leading to potential user injury due to uncontrolled relative motion speeds, especially when the orientation is perpendicular to the ground.

Innovation Solution

A telescopic pole assembly with a guiding element that includes a bushing part and a braking part with a movable braking element, providing a constant braking force through a cantilever design, ensuring controlled insertion and extraction speeds by maintaining consistent frictional contact between the inner and outer tubes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If friction resistance material is used between sliding tubes to provide braking function, then braking force is provided to control relative motion speed, but brake resistance is lowered due to abrasion causing uncontrolled motion

Engineering Contradiction:
Improvebraking control reliabilityVSAvoidservice life of braking material
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

A guiding element is introduced as an intermediary component between the inner tube and outer tube. This guiding element includes a braking surface that provides frictional contact with the inner tube, acting as a mediator to transfer and control the braking force. The guiding element can be independently replaced when worn, preserving the expensive tubes while maintaining braking functionality throughout the service life.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The guiding element is designed as a consumable component with lower cost compared to the tubes. It is intended to be replaced periodically when the braking surface becomes worn, while the expensive inner and outer tubes can be reused. This approach sacrifices a cheaper component to protect the longevity of the entire telescopic assembly.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Reliability

If frusto-conical friction elements are used to provide braking force, then braking function is achieved, but non-uniform braking force is applied causing user control difficulty

Engineering Contradiction:
Improvebraking function effectivenessVSAvoiduser control over braking force
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The braking surface on the guiding element is designed with specific local geometric properties - a cylindrical surface with controlled roughness or specific material characteristics. This localized quality control ensures uniform frictional contact across the contact area, providing consistent and predictable braking force that the user can easily control, unlike the non-uniform pressure distribution of frusto-conical elements.

Inventive Principle:
Principle #3Local quality

3Length of moving object

If sliding tubes are oriented perpendicular to ground for maximum height, then working tool reaches highest location, but relative motion speed increases causing safety hazard

Engineering Contradiction:
Improveheight reach of working toolVSAvoiduser injury risk from uncontrolled motion
Core Design Contradiction:
Length of moving objectVSObject-affected harmful factors

Solution Approach 1:

The guiding element with its braking surface is installed in advance to counteract the gravitational force that accelerates the inner tube during perpendicular extraction. The frictional contact provided by the guiding element creates a preliminary opposing force that limits the maximum speed of the inner tube, preventing it from reaching dangerous velocities even when oriented perpendicular to ground.

Inventive Principle:
Principle #9Preliminary anti-action

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

The solution ensures safe and controlled operation by providing a consistent braking force, reducing abrasion and enabling users to manage the speed of the telescopic pole assembly effectively, thus preventing accidents and maintaining tool functionality over its lifetime.

Implementation Method 1

The braking element (148) includes a braking surface (150) which is in frictional contact with the inner tube (124)

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

The guiding element (134) includes a front part (137) and a rear part (136)... providing a constant braking force through a cantilever design

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3262307B1Telescopic pole assembly for working tool
Publication Date: 2020.03.18 HUSQVARNA AB
  • EP3262307B1 patent drawingFigure 1
  • EP3262307B1 patent drawingFigure 2
  • EP3262307B1 patent drawingFigure 3

AI summary

The present invention discloses a telescopic pole assembly (104) for attachment to a working tool (102). The telescopic pole assembly (104) includes an inner tube (124), an outer tube (126), and a locking assembly (128) configured to lock and unlock the inner tube (124) with respect to the outer tube (126). Further, a guiding element (134) is connected to either one of the inner tube (124) or the outer tube (126) which includes at least one bushing part (140) and at least one braking part (142). Moreover, the at least one braking part (142) having a movable braking element (148) is configured to provide the braking force between the inner tube (124) and the outer tube (126) when the inner tube (124) is unlocked with respect to the outer tube (126).