Unload Lever Cam Groove Locking Against Unintended Shifting
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Solution Overview
Problem
Existing working machines with lever devices face challenges in preventing unintended shifting from an unloading state to a loading state, particularly when operators inadvertently push down on parts other than the unload lever, leading to operational errors and safety concerns.
Innovation Solution
A lever device with a cam groove mechanism and a biasing member that rotates a cam body about a second lateral shaft, allowing the guide pin to move between upper and lower groove positions, ensuring the unload lever can only be switched between push-down and pull-up positions securely, preventing unintended state changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a guide pin engages with a guide groove to prevent unintended shifting, then reliability is improved, but device complexity increases
Solution Approach 1:
The guide pin and guide groove are integrated into the existing cam body mechanism. The guide groove is formed directly on the cam body surface, and the guide pin is incorporated into the cam follower structure, merging the positioning function with the existing motion transmission components rather than adding separate guiding mechanisms.
Solution Approach 2:
The cam body acts as an intermediary element that mediates between the lever input and the hydraulic control output. The guide groove on the cam body surface guides the guide pin to ensure proper engagement and prevent unintended state changes, while the cam body itself rotates to transmit the controlled motion.
2Ease of operation
If a cam groove mechanism with multiple groove portions is used, then ease of operation is improved, but manufacturing precision requirements increase
Solution Approach 1:
The cam groove is segmented into three distinct portions: an intermediate groove portion, an upper groove portion, and a lower groove portion. Each portion serves a specific function in guiding the guide pin during different phases of lever operation, allowing for controlled positioning at key states while simplifying the overall groove design compared to a single complex continuous groove.
Solution Approach 2:
The cam groove portions are designed with curved geometries rather than sharp angles or straight lines. The intermediate groove portion is curved to be convex in a direction separating from the first lateral shaft, and the upper and lower groove portions are curved to guide the pin smoothly between positions, reducing stress concentrations and simplifying manufacturing.
3Reliability
If a biasing member is added to press the cam body, then reliability is improved, but device complexity increases
Solution Approach 1:
The biasing member provides a counteracting force that presses the cam body in a direction to rotate it about the second lateral shaft, balancing the forces during lever operation and ensuring reliable engagement between the guide pin and guide groove throughout the motion range.
Solution Approach 2:
The biasing member serves multiple functions: it maintains engagement between the guide pin and guide groove, ensures proper positioning of the cam body during rotation, and provides stability throughout the lever's motion range. This single component performs what would otherwise require multiple separate 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 configuration effectively prevents unintended state changes, enhancing operational safety and reducing the risk of accidental activation of hydraulic actuators, while also simplifying the design and reducing manufacturing costs by minimizing the number of parts and connector portions.
Implementation Method 1
a first biasing member (51) pressing the cam body (33) in a direction to rotate the cam body (33) about the second lateral shaft (32)
Data Source
AI summary
A lever device includes a base pedestal, a movable body, a lever, a cam body having a cam groove, a guide pin, and a first biasing member. The lever is configured to swing between a push-down position at which the guide pin is arranged in the upper groove portion and a pull-up position at which the guide pin is arranged in the lower groove portion. The first biasing member has one end connected to a first connector portion provided on the base pedestal; and the other end connected to a second connector portion provided on the cam body, is arranged behind the second lateral shaft when the lever is located at the push-down position, and is arranged in front of the second lateral shaft when the lever is located at the pull-up position.