Sport Stick Locking Device with Toggle Lever and Interlocking Recess

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Solution Overview

Problem

Conventional sports sticks with adjustable lengths suffer from instability issues due to the non-positive connection between the inner and outer tubes, leading to unintended shortening or twisting, especially under load or after prolonged use, and require significant force to operate the locking mechanism.

Innovation Solution

The sports stick incorporates a locking device with a projection and recess system that creates a form-fitting connection between the inner and outer tubes, providing additional security against rotation and displacement, and a toggle lever mechanism that converts small input forces into high clamping forces with minimal friction, ensuring stability and ease of use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a clamp with frictional contact is used to hold the inner tube in the outer tube, then the sports stick can be adjusted to different lengths, but the connection becomes unstable under load or after prolonged use

Engineering Contradiction:
ImproveadjustabilityVSAvoidstability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The locking mechanism is divided into two independent functions: a clamp for applying clamping force and a projection-recess system for positive locking. This segmentation allows each component to specialize, with the projection-recess pair providing stable positional locking while the clamp provides the necessary holding force, thereby resolving the contradiction between adjustability and stability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The projection and recess act as intermediary elements that mediate between the inner tube and outer tube, creating a positive connection that supplements the frictional contact. This intermediary mechanism ensures that the tubes remain locked in their adjusted position even under load, while still allowing for length adjustment when needed.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If an eccentric cam mechanism is used to create clamping force, then the locking device can be operated, but significant force is required and wear occurs at the contact point

Engineering Contradiction:
ImproveoperabilityVSAvoidwear resistance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The eccentric cam mechanism is replaced with a lever system that provides mechanical advantage. The lever system converts small input forces into high clamping forces through leverage, reducing the effort required to operate the locking device while eliminating the wear-prone eccentric cam contact, thereby improving both ease of operation and wear resistance.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The operating mechanism transitions from an eccentric cam system to a lever system, changing the mechanical parameters of force application. The lever system provides a more favorable force multiplication ratio, requiring less input force to achieve the necessary clamping force, thus improving operability while reducing wear on moving parts.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the clamp diameter is reduced to exert clamping force, then the inner tube is clamped securely, but the operating lever requires large force to overcome friction

Engineering Contradiction:
Improveclamping securityVSAvoidoperating force
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The projection-recess system acts as an intermediary that provides positive locking without requiring additional operating force. Once the clamp is closed, the projection engages with the recess to secure the position, eliminating the need to overcome friction to maintain locking security, thus improving ease of operation while maintaining clamping security.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The projection-recess mechanism provides self-locking functionality where the geometric engagement automatically secures the tube position without requiring continuous operating force. The system serves itself by using the relative positioning of the projection and recess to maintain the locked state, reducing the force required for operation while ensuring reliable clamping.

Inventive Principle:
Principle #25Self-service

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 enhances the stability and reliability of the sports stick by preventing unintended adjustments and reducing wear, allowing for easy length adjustments and secure locking, even under challenging conditions, while minimizing the force required for operation.

Implementation Method 1

The non-positive connection (frictional contact) created by the clamp between the outer tube and the inner tube

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

the locking device has a projection which projects inwards on the inner circumference of the clamp, and that the inner tube has at least one recess into which the projection engages in the locking state

Methodology Applied
Scientific EffectMechanical Interlocking: Mechanical Fastener

Data Source

PatentEP2213192B1Sport stick
Publication Date: 2012.02.29 SALEWA SPORT
  • EP2213192B1 patent drawingFigure 1a~1c
  • EP2213192B1 patent drawingFigure 2a~2c
  • EP2213192B1 patent drawingFigure 3a~3c

AI summary

The pole (10) has a locking device (16) manually adjusted between dismantling and locking conditions. The locking device includes a lug (28) that is inwardly projected toward inner circumference of a clamping piece. An internal tube (14) includes a recess (30), and the lug is engaged in the recess in a locking state. An internal lug includes a lug that is outwardly projected at outer circumference of the internal tube. The locking device includes another recess that engages with the latter lug in the locking state, where the latter lug is formed by a lever arm.