Extendable Tool Spring-Loaded Locking Mechanism

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Solution Overview

Problem

Existing extendable handheld tools, such as pruning tools, face challenges in precision and efficiency due to complex and inconvenient telescopic extension mechanisms, which require manual operation and are often difficult to use in hard-to-reach locations.

Innovation Solution

An extendable tool design featuring an outer and inner tube with a slider member and a roller ball locking element, allowing for easy length adjustment through a simple and ergonomic mechanism with limited moving components, including a spring-biased slider and an inclined surface engagement member.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a button and locking bolt mechanism is used for telescopic extension, then the telescopic tubes can be locked at desired positions, but the operation becomes complex and inconvenient requiring multiple manual steps

Engineering Contradiction:
Improvelocking reliabilityVSAvoidoperation convenience
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The spring-loaded locking element automatically engages with the receiving portion when the inner tube is inserted into the outer tube, and automatically disengages when the tubes are pulled apart. The system serves itself by using the relative movement between tubes to trigger the locking and unlocking actions without requiring manual operation of buttons or bolts.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The complex button and locking bolt mechanism is removed entirely from the design. Only the essential locking function is retained through a simplified spring-loaded element that performs both locking and unlocking functions automatically based on tube movement.

Inventive Principle:
Principle #2Taking out (Extraction)

2Device complexity

If the button is located at a distant location on the handle, then the locking mechanism can be positioned far from the user's hand, but the operation of the button becomes difficult and inconvenient

Engineering Contradiction:
Improvemechanism positioningVSAvoidbutton accessibility
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The distant button is completely removed from the design. The locking mechanism operates automatically through the relative movement between the inner and outer tubes, eliminating the need for any manually operated button or control element.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If multiple manual steps are required to extend or retract the telescopic tubes, then the locking can be secured, but the process becomes inefficient and time-consuming

Engineering Contradiction:
Improvelocking securityVSAvoidextension efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The spring-loaded locking element automatically engages when the inner tube is inserted into the outer tube and automatically disengages when the tubes are pulled apart. This single automatic action replaces multiple manual steps, significantly improving the efficiency of extending and retracting the telescopic tubes while maintaining secure locking.

Inventive Principle:
Principle #25Self-service

4Reliability

If a complex locking mechanism with multiple components is used, then the locking function can be achieved, but the design becomes complicated and manufacturing cost increases

Engineering Contradiction:
Improvelocking functionVSAvoidmanufacturing simplicity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The complex locking mechanism with multiple components (buttons, locking bolts, springs, levers) is reduced to a single spring-loaded locking element that works in conjunction with a receiving portion. This minimal component design maintains the locking function while dramatically simplifying the design and reducing manufacturing complexity and cost.

Inventive Principle:
Principle #2Taking out (Extraction)

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 provides a user-friendly, cost-effective, and efficient way to adjust the tool length, enhancing operational precision and comfort by simplifying the extension and retraction process while maintaining the desired length.

Implementation Method 1

The slider member is a spring biased type slider member

Methodology Applied
Scientific EffectSpring biasing: Spring

Data Source

PatentEP3751982B1Extendable tool
Publication Date: 2023.06.21 HUSQVARNA AB
  • EP3751982B1 patent drawingFigure 1
  • EP3751982B1 patent drawingFigure 2
  • EP3751982B1 patent drawingFigure 3

AI summary

An extendable tool (100) includes an outer tube (102), an inner tube (108) including at least one receiving portion (206, 214), and a handle portion (112) including a slot (114) provided therein. A slider member (116) is provided within the slot (114) and is adapted to slide within the slot (114) between a first position (P1) and a second position (P2). The extendable tool (100) also includes a locking element (208) adapted to be selectively engaged with the at least one receiving portion (206, 214) such that the locking element (208) limits movement of the inner tube (108) with respect to the outer tube (102). The extendable tool (100) further includes an engagement member (210) having an inclined surface (212) and coupled with the slider member (116). The engagement member (210) is adapted to slide within the outer tube (102). In the first position (P1), the slider member (116) actuates the engagement member (210) such that the inclined surface (212) of the engagement member (210) engages the locking element (208) with respect to the at least one receiving portion (206, 214).