Control Lever Unit with Directional Stop Portions
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Solution Overview
Problem
Existing control lever units for working vehicles, such as forklifts, face issues with erroneous operations when tilted to the maximum in the main operation direction, leading to excessive force requirements and operator fatigue, as strong resistance in the intermediate direction can be overcome, causing unintended tilting and reduced working efficiency.
Innovation Solution
A control lever unit featuring a pivoted lever with a sensor to detect tilt angles, an elastically undeformable restricting member with specific stop portions to limit tilting ranges, and a coil spring providing varying restoring forces to prevent erroneous tilting, ensuring accurate operation in main directions without excessive heaviness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If strong resistance is applied in the intermediate direction to prevent erroneous operation, then the lever becomes heavy to operate in the intermediate direction, but this causes operator fatigue and may still be overcome when tilted to maximum in main direction
Solution Approach 1:
The restricting member provides different resistance characteristics in different directions: it offers strong restriction in intermediate directions to prevent erroneous operation, while allowing smooth movement in main operation directions. This directional differentiation of mechanical properties resolves the contradiction between preventing errors and maintaining ease of operation.
Solution Approach 2:
The system dynamically adapts its resistance based on the lever's position and direction of movement. The restricting member's geometry creates variable resistance that is high when attempting intermediate movements from extreme positions but low during normal main direction operations, resolving the contradiction between reliability and ease of operation.
2Ease of operation
If the lever is tilted to maximum in the main operation direction, then it is easy to apply operation force, but this creates risk of erroneous displacement toward intermediate direction
Solution Approach 1:
The restricting member is designed to provide preliminary resistance before erroneous displacement can occur. When the lever reaches maximum tilt in a main direction, the restricting member's geometry pre-positions stop portions that will contact the lever if movement toward an intermediate direction is attempted, preventing erroneous operation before it can happen.
Solution Approach 2:
The restricting member acts as an intermediary mechanical element between the lever and the operator's force. It mediates the interaction by allowing force application in main directions while blocking force that would cause intermediate direction movement, thus resolving the contradiction between ease of force application and operational accuracy.
3Measurement precision
If strong restoring force is applied in intermediate direction to prevent erroneous operation, then operational accuracy is improved, but the lever becomes excessively heavy to tilt intentionally in intermediate direction
Solution Approach 1:
The restricting member creates localized mechanical constraints that provide strong restoring force only in intermediate directions where erroneous operation must be prevented. In main operation directions, the same structure provides minimal resistance, effectively creating direction-dependent mechanical properties that resolve the contradiction between positioning accuracy and effective weight.
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 effectively prevents erroneous operations by guiding the lever back to the neutral position, reducing operator fatigue and enhancing working efficiency by providing distinct operational feedback for main and intermediate directions, thus ensuring precise control and simplified operation.
Implementation Method 1
a coil spring (26) which provides a restoring force for returning the lever (22) to the neutral position
Implementation Method 2
a sensor (31, 32) for detecting a tilt angle of the lever (22) in the two respective main operation directions (D1, D2)
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A control lever unit includes a lever (22), a sensor, an urging body and an elastically undeformable restricting member. The lever is pivoted tiltably from a neutral position in any direction within 360 degrees including two main operation directions and intermediate directions therebetween. The sensor detects tilt angle of the lever (22) in the two respective main operation directions. The urging body puts the lever back to the neutral position. The restricting member has an interior wall for surrounding the lever to restrict tilting range of the lever. Contour of the interior wall of the restricting member includes main operation stop portions for specifying tilt limit of the lever in the main operation directions and intermediate stop portions for specifying tilt limit of the lever in the intermediate directions. The main operation stop portions are positioned outside a quadrangle with the intermediate stop portions at apexes thereof.