Work Vehicle Operation Lever Linkage Mechanism
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Solution Overview
Problem
Existing work vehicles with single operation levers for speed change and parking brake operations face issues with operability, particularly increased risk of erroneous operations and inadvertent release of the parking brake, due to complex path arrangements and lack of clear linkage mechanisms.
Innovation Solution
A work vehicle design incorporating a single pivotable operation lever with separate link mechanisms for speed changer and parking brake operations, featuring a locking mechanism with a retaining portion and a retained portion for secure engagement, ensuring that speed changing and parking brake operations are performed through a series of pivotal movements without linking the operation lever with the parking brake mechanism unless intentionally activated.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single operation lever is used for both speed change and parking brake operations, then the number of operations is reduced, but the risk of erroneous operation and inadvertent release increases
Solution Approach 1:
The operation lever's movement path is segmented into distinct zones: a first movement range for speed change operations and a second movement range for parking brake operations. These ranges are spatially separated and do not overlap, allowing the single lever to perform multiple functions while preventing erroneous operations through clear path differentiation.
Solution Approach 2:
A linkage mechanism acts as an intermediary between the operation lever and the parking brake mechanism. This linkage is selectively engaged only when the lever is in the second movement range, preventing accidental activation during speed change operations in the first range while enabling intentional parking brake application.
2Reliability
If complex path arrangements are used to separate operations, then operational clarity improves, but device complexity increases
Solution Approach 1:
The single operation lever serves multiple functions by utilizing different movement ranges along its pivot path. The lever structure itself is simple and universal, but its multi-functional capability is achieved through the control system that recognizes different positional ranges and activates corresponding functions, avoiding the need for separate levers or complex mechanical path differentiation.
Solution Approach 2:
The patent replaces complex mechanical path arrangements with a control system that detects the lever's positional range and activates appropriate functions electronically or through controlled linkage engagement. This substitution maintains operational clarity while significantly reducing mechanical complexity.
Data Source
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AI summary
When an operation lever (19A) is operated to either a speed changing path or a neutral path, a second link mechanism establishes no operative coupling between the operation lever and a parking brake mechanism (17). When the operation lever is operated from the neutral path to a linking path, the second link mechanism establishes operative coupling between the operation lever and the parking brake mechanism. Further, when the operation lever is operated to a braking path, the parking brake mechanism is activated. When the lever is operated to a locking path, a locking mechanism (18) is activated.