Belt Tensioner Dual-Locking Spring Mechanism

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Solution Overview

Problem

Existing belt tensioners face challenges in achieving a compact design while ensuring secure locking and easy handling, with difficulties in assembly and unlocking, particularly requiring two-handed operation and involving significant effort.

Innovation Solution

A belt tensioner design featuring a spring element with two locking sections that engage in latching grooves on the base body, allowing for double locking and easy one-handed unlocking, with a low overall height and simplified assembly through elongated hole openings and a closed spring element design, enabling secure locking and easy retrofitting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single locking section is used in the spring element, then the assembly is simpler, but the locking security is insufficient

Engineering Contradiction:
Improvelocking securityVSAvoidspring element structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The spring element is divided into two separate locking sections (first locking section and second locking section) that engage with respective latching grooves on the base body. This segmentation provides dual locking points, significantly enhancing locking security and reliability while maintaining a relatively simple overall spring element structure that can be manufactured as a single piece.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the tensioning lever is designed with a larger height, then the locking mechanism has more space, but the overall device size increases

Engineering Contradiction:
Improvelocking mechanism stabilityVSAvoidtensioning lever height
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The locking mechanism utilizes the width dimension of the tensioning lever by positioning locking sections at different lateral positions (first side wall and second side wall) rather than stacking them vertically. This dimensional redistribution allows sufficient locking mechanism stability without increasing the overall height of the tensioning lever, keeping it at most 20 mm.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If a U-shaped spring element with exact threading is used, then the locking is secure, but the assembly becomes difficult

Engineering Contradiction:
Improvelocking securityVSAvoidassembly difficulty
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The spring element is designed with two locking sections that automatically engage with the latching grooves on the base body through elastic deformation and mechanical pretensioning. The spring element self-secures itself without requiring precise threading or additional fastening operations, enabling simple assembly while maintaining secure locking.

Inventive Principle:
Principle #25Self-service

4Reliability

If the spring element requires two-handed operation for unlocking, then the locking is more secure, but the ease of operation decreases

Engineering Contradiction:
Improvelocking securityVSAvoidunlocking operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The handling section of the spring element is extracted and extended beyond the free end of the tensioning lever, providing a dedicated one-handed actuation point. This allows the user to apply force to a single location on the spring element to simultaneously release both locking sections, maintaining locking security while enabling convenient one-handed operation.

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 enhanced security and ease of use by allowing secure locking with minimal force and intuitive one-handed operation, while reducing assembly complexity and enabling a compact design with a maximum height of 20 mm.

Implementation Method 1

the spring element has a first locking section which extends outwards through a first side cheek of the tensioning lever and engages in a first latching groove formed in a first side cheek of the base body, and a second locking section which extends outwards through a second side cheek of the tensioning lever and engages in a second latching groove formed in a second side cheek of the base body in the locking position of the tensioning lever and is held therein by the mechanical pretensioning of the spring element

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3117734B9Belt tensioner
Publication Date: 2019.12.04 FRANZ MIEDERHOFF OHG
  • EP3117734B9 patent drawingFigure 1
  • EP3117734B9 patent drawingFigure 2
  • EP3117734B9 patent drawingFigure 3

AI summary

The present invention relates to a belt tensioner (1) comprising: - a base body (2) with a bottom section (20) and two side cheeks (21, 22), - a tensioning lever (3) with two side cheeks (30, 31) which is pivotably connected to the base body (2) and can be pivoted from an unlocked position to a locked position and vice versa, and - locking means which are configured to lock the tensioning lever (3) to the base body (2) in the locked position, wherein the locking means comprise: - a spring element (4) which is arranged on an inner side of the tensioning lever (3) facing the bottom section (20) in the locked position and has a first locking section (43) which extends outwards through a first side cheek (30) of the tensioning lever (3), and - a first locking groove (210).which is formed in a first side wall (21) of the base body (2) and into which the first locking section (43) engages in the locking position of the clamping lever (3) and is held therein to block an opening movement of the clamping lever (3) by a mechanical preload of the spring element (4), wherein the spring element (4) has a handling section (40) which can be acted upon by a user with an external force, so that the first locking section (43) can be moved out of the first detent groove (210) against the preload of the spring element (4), wherein the spring element (4) has a second locking section (44) which extends outwards through a second side wall (31) of the clamping lever (3), and wherein the locking means comprise a second detent groove (211),which is formed in a second side wall (22) of the base body (2) and into which the second locking section (44) engages in the locking position of the clamping lever (3) and is held therein to block the opening movement of the clamping lever (3) by the mechanical preload of the spring element (4).