Operating Lever Lock Pin Intersecting Swing Arm Surface
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Solution Overview
Problem
Walk-behind working machines face operational challenges due to adhesion of dust and dirt in their lock mechanisms, leading to reduced reliability and smooth operation over time.
Innovation Solution
The operating lever unit incorporates a lock lever with a lock pin that interlocks with a swing arm, allowing for smooth operation by preventing dirt and dust from interfering with the engagement, and features a pin engagement surface that intersects with the lock pin's path, enabling a large dimensional tolerance and reliable engagement even under vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the lock pin and bracket are used in a conventional lock mechanism, then the mechanism can provide locking function, but the adhesion of foreign matters such as dust and dirt reduces smooth operation over time
Solution Approach 1:
The patent extracts the locking function from the conventional lock pin-bracket configuration and relocates it to the swing arm itself. The swing arm is designed with a locking portion that engages with the operating lever, eliminating the need for a separate lock pin and bracket assembly that are prone to dust adhesion. This extraction of the locking function to the moving swing arm resolves the contradiction by removing the vulnerable stationary locking components.
Solution Approach 2:
The patent introduces a locking portion on the swing arm as an intermediary element between the operating lever and the swing arm. This locking portion includes a locking surface that interacts with a corresponding surface on the operating lever, creating a reliable locking mechanism without requiring traditional lock pins or brackets that are susceptible to dust and dirt adhesion.
2Reliability
If the lock pin is disposed parallel to the support shaft, then the locking function can be achieved, but the dimensional tolerance is limited and engagement reliability is reduced under vibrations
Solution Approach 1:
The patent changes the orientation of the locking surface from a parallel arrangement to an intersecting arrangement. The locking surface on the swing arm is disposed at an angle that intersects with the path of the operating lever, creating a two-dimensional engagement surface rather than a linear parallel contact. This dimensional change provides larger dimensional tolerance and maintains engagement reliability under vibrations by creating a more robust intersecting engagement geometry.
Data Source
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AI summary
An operating lever unit (30) for a walk-behind working machine includes an operating lever (50) pivotally disposed adjacent to a grip (18) of a handlebar (16a) for being gripped with a human operator together with the grip, a swing arm (70) pivotally disposed adjacent to the grip for operating an operated member of the walk-behind working machine, and a lock lever (60) pivotally mounted on the operating lever for operation by the human operator to releasably lock the swing arm in position relative to the operating lever. The lock lever includes a lock pin (65) adapted to be engaged with a part of the swing arm when the lock lever is operated by the human operator.