Telescopic Pruner Pulley Layout for Protected Internal Pulling Means

Solution Overview

Problem

Existing telescopic hand tools with multiple tubes often have visible and externally guided pulling means, which can be cumbersome and prone to direct material contact, leading to friction and wear, and may not provide easy operation.

Innovation Solution

A telescopic hand tool design with pulling means arranged substantially inside the tubes, utilizing deflection and hoist pulleys to redirect the pulling force, and incorporating telescopic interfaces to minimize direct tube contact and optimize pulling means guidance, with visible portions protected within channels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the pulling means is arranged externally and guided in grooves on the tube surface, then the structure is simpler and easier to manufacture, but the pulling means is visible and prone to direct material contact leading to friction and wear

Engineering Contradiction:

Improvedurability of pulling meansVSAvoidcomplexity of pulling means arrangement

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The pulling means is nested inside the telescopic tubes rather than being externally exposed. The cord runs through the interior space of the tubes, protected from external contact and environmental factors, which reduces wear and improves durability while maintaining structural integrity.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

Pulleys are introduced as intermediary elements to redirect the pulling means inside the tubes. These pulleys allow the cord to change direction and transmit force effectively while remaining protected within the tube structure, avoiding direct contact between the pulling means and external surfaces.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If the pulling means is arranged inside the tubes, then the pulling means is protected and less visible, but the arrangement becomes more complex requiring pulleys and internal guidance structures

Engineering Contradiction:

Improveprotection of pulling meansVSAvoidcomplexity of internal arrangement

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The pulling means is nested inside the telescopic tubes rather than being externally exposed. The cord runs through the interior space of the tubes, protected from external contact and environmental factors, which reduces wear and improves durability while maintaining structural integrity.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

Pulleys are introduced as intermediary elements to redirect the pulling means inside the tubes. These pulleys allow the cord to change direction and transmit force effectively while remaining protected within the tube structure, avoiding direct contact between the pulling means and external surfaces.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If multiple telescopic interfaces are provided between tubes, then direct material contact between tubes is inhibited reducing fretting, but the device complexity increases

Engineering Contradiction:

Improveresistance to fretting wearVSAvoidnumber of telescopic interfaces

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The telescopic structure is divided into multiple segments with separate telescopic interfaces between the outer tube and intermediate tube, and between the intermediate tube and inner tube. This segmentation prevents direct contact between the outer tube and inner tube, eliminating fretting wear at their interface while allowing independent movement of each segment.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The intermediate tube acts as an intermediary element between the outer tube and inner tube. It transmits telescopic movement while preventing direct contact between the outer and inner tubes, thereby protecting against fretting wear through the introduction of this middle element.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Object-affected harmful factors

If the pulling means is made invisible by arranging it inside the tubes, then aesthetics and protection are improved, but operation ease may be compromised

Engineering Contradiction:

Improveprotection of pulling meansVSAvoidease of operation

Core Design Contradiction:

Object-affected harmful factorsVSEase of operation

Solution Approach 1:

Pulleys are introduced as intermediary elements to redirect the pulling means inside the tubes. These pulleys allow the cord to change direction and transmit force effectively while remaining protected within the tube structure, avoiding direct contact between the pulling means and external surfaces.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The pulling means is made homogeneous with the tube interior by routing it through the same space as the telescopic tubes occupy. This integration allows the pulling mechanism to be aesthetically unified with the tube structure while maintaining full operational functionality through proper pulley placement.

Inventive Principle:

Principle #33Homogeneity

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, low-friction, and durable telescopic hand tool operation with enhanced protection of the pulling means, allowing easy handling and reduced wear, while maintaining a wide range of adjustable lengths.

Implementation Method 1

a number of deflection pulleys arranged at the back ends of the tubes and at the front ends of the outer tube and intermediate tube, wherein the deflection pulleys are provided for redirecting the pulling means, a hoist pulley slidable within the inner tube and connected to the tool head by at least one rod, band, or further cord, wherein the hoist pulley is provided for redirecting the pulling means such that an operator force is amplifiable

Methodology Applied

Scientific EffectPulley: Pulley

Data Source

PatentEP4606210B1Telescopic hand tool, in particular telescopic pruner

Publication Date: 2026.03.11 HUSQVARNA AB

Figure 1
Figure 2~3
Figure 4~5

AI summary

The present invention relates to a telescopic hand tool (10), in particular a telescopic pruner. The telescopic hand tool (10) comprises an outer tube (12), at least one intermediate tube (14) slidable within the outer tube (12) and an inner tube (18) slidable within the intermediate tube (14). At least one tool head (32) is connected or connectable to the front end of the inner tube (18). A back handle (44) is detachably arranged at the back end of the outer tube (12). A pulling means (18) is arranged substantially inside the tubes (12, 14, 16), wherein one end of the pulling means (18) is connected to the back handle (44), while another end of the pulling means (18) is connected to a fixing point (54) at the front end of the outer tube (12). A number of deflection pulleys (22, 24, 26, 28, 30) is arranged at the back ends of the tubes (12, 14, 16) and at the front ends of the outer tube (12) and intermediate tube (14), wherein the deflection pulleys (22, 24, 26, 28, 30) are provided for redirecting the pulling means (18). A hoist pulley (20) is slidable within the inner tube (16) and connected to the tool head (32), wherein the hoist pulley (20) is provided for redirecting the pulling means (18). A pull sleeve (38) is connected to the pulling means (18) and slidable along the outer tube (12). At least one elongated channel (46) is arranged at the outer side of the outer tube (12) and extends parallel to the longitudinal axis of said outer tube (12). At least one portion of the pulling means (18) is guided within the channel (46).