Tensioner Lever Spring Locking to Prevent Chain Vibration
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Solution Overview
Problem
Existing tensioner levers face issues with component looseness during transport, potential disengagement of the support arm, and excessive chain tension leading to vibration and noise due to the design's reliance on a stopper pin and lack of backward movement restriction.
Innovation Solution
A tensioner lever design that eliminates the need for a stopper pin by using the coil spring's resilience to engage the support arm with an engagement portion on the lever body, reducing the number of components and weight, while incorporating a locking arm to restrict backward movement and prevent chain flapping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stopper pin is used to lock the support arm, then the support arm is secured during transport, but the number of components increases and the weight increases
Solution Approach 1:
The patent removes the stopper pin component entirely and replaces it with an engagement portion integrated into the lever body structure. The support arm engages with this engagement portion through elastic deformation, eliminating the need for separate locking components while maintaining retention reliability during transport and assembly.
2Reliability
If a stopper pin is used to lock the support arm, then the support arm is secured during transport, but the weight of the tensioner lever increases
Solution Approach 1:
By extracting the stopper pin component and integrating the engagement portion directly into the lever body, the patent reduces the overall weight of the tensioner lever assembly while maintaining the support arm's secure retention through elastic engagement.
3Reliability
If the coil spring is largely resiliently deformed in the stopper pin design, then the support arm can be locked, but stress causes deformation of the lever body over time
Solution Approach 1:
The engagement portion is designed to utilize the elastic deformation of the support arm itself to achieve locking, rather than relying on large deformation of the coil spring. The support arm's own elasticity provides the locking force, reducing stress on the lever body and preventing long-term deformation while maintaining reliable support arm retention.
4Device complexity
If the tensioner lever design does not restrict backward movement, then the structure is simpler, but chain tension causes vibration and noise
Solution Approach 1:
The engagement portion and support arm design inherently restricts backward movement of the lever body by creating a mechanical stop through elastic engagement. This preliminary restriction prevents excessive chain tension from causing vibration and noise while maintaining relatively simple structure without requiring additional separate restricting mechanisms.
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
This design ensures secure engagement and assembly of the tensioner lever, reduces deformation, and minimizes vibration and noise by maintaining chain tension without additional mechanisms.
Implementation Method 1
the coil spring including a helical part loosely fitted to a boss part provided to the lever body, a pressing arm extending from one end of the helical part and contacting the lever body, and a support arm extending from another end of the helical part and supported by the attachment surface, the lever body including an engagement portion with which the support arm removably engages and which retains the coil spring in a compressed state
Implementation Method 2
the engagement portion being configured to allow the support arm to be hooked thereon by resilient deformation, and to engage therewith by rebound resilience of the coil spring
Implementation Method 3
a torsion coil spring interposed between the lever body and the attachment surface to press the shoe surface toward the chain
Data Source
AI summary
An object of the present invention is to provide a tensioner lever that allows for reduction of the number of components and the weight, while being able to prevent vibration and noise during the running of the chain. The tensioner lever according to the present invention is configured such that a lever body rotatably supported on an attachment surface is urged to rotate toward the chain by the resilient force of a coil spring. The coil spring includes a pressing arm extending from one end of a helical part and contacting the lever body, and a support arm extending from another end of the helical part and supported by the attachment surface. The lever body includes an engagement portion configured to allow the support arm of the coil spring to be hooked thereon by resilient deformation, and to removably engage therewith by rebound resilience of the coil spring.