Excavator Lever-Switch Interlock to Prevent Control Mis-Operation
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Solution Overview
Problem
In shovels with operating levers and switches installed on both sides of the operator's seat, there is a risk of switch mis-operation when the operator's body touches the switches while operating the levers, leading to unintended switch activation.
Innovation Solution
The implementation of an operating device configuration where switches are positioned to prevent accidental activation by the operator's body during lever operation, with the controller disabling switch functions when the operating lever is in use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If switches are placed near the operating levers for easy operation, then the ease of operation is improved, but the reliability deteriorates due to risk of mis-operation when operator's body touches the switches
Solution Approach 1:
The switch operation state is dynamically changed based on the operating lever state. When the operating lever is detected to be operated, the switch operation is disabled (switched to non-operable state). This dynamic adjustment resolves the contradiction by making the switch accessible during non-operation for ease of use, but automatically protecting it during lever operation to prevent mis-operation.
Solution Approach 2:
The control unit continuously monitors the operating lever state and provides feedback control to the switch operation state. When the lever operation is detected, the control unit automatically disables switch operation. This feedback mechanism ensures that the switch remains accessible when needed while automatically preventing mis-operation when the lever is being used, thus resolving the contradiction between ease of operation and reliability.
2Reliability
If switches are positioned away from operating levers to prevent mis-operation, then the reliability is improved, but the ease of operation deteriorates as operator must change posture to reach switches
Solution Approach 1:
Instead of statically positioning switches far from levers, the system dynamically controls switch operability based on lever state. The switches remain physically accessible near the levers for ease of operation, but the control unit dynamically disables switch operation when lever operation is detected, thus maintaining reliability without sacrificing accessibility.
Solution Approach 2:
The system provides self-protection functionality where the control unit automatically detects lever operation and disables switch operation without requiring additional operator action. This self-service mechanism prevents mis-operation while keeping switches in convenient positions, resolving the contradiction between reliability and ease of operation.
Data Source
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AI summary
A shovel (150) includes a lower traveling body (1), an upper turning body (3) turnably mounted on the lower traveling body (1), a cabin (10) mounted on the upper turning body (3), an operator's seat (100) installed in the cabin (10), a right operating lever (26B) installed in the cabin (10), and a switch (41a to 41f) installed in the cabin (10), where the switch (41a to 41f) is disabled when the right operating lever (26B) is operated.