Excavator Cab Control Box Interlock for Safe Tilt Access
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Solution Overview
Problem
Existing safety lever systems in excavator cabs fail to prevent unintended operation of control levers and buttons during an operator's entry or exit, leading to potential malfunctions and accidents due to unconscious actions.
Innovation Solution
A safety lever system with a tilting device and limit means, where a rotating bracket and spring bracket interlock to immobilize the control box, and a limit switch controls power application/short-circuiting based on the tilting angle, ensuring the control box cannot descend without intentional operation of the safety lever.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the safety lever system remains shut down until the operator operates the system, then safety is improved, but the ease of operation deteriorates due to the additional step required
Solution Approach 1:
The control box is pre-configured with a limit switch that automatically shuts down power when in the tilted position. The system is prepared in advance with safety interlocks built into the electrical circuit, so that when the operator tilts the control box, the power is already disconnected without requiring manual operation of a safety lever.
Solution Approach 2:
The manual safety lever operation is extracted and replaced by an automatic limit switch mechanism. The limiting function is separated from manual control and embedded directly into the tilting mechanism's electrical circuit, eliminating the need for separate safety lever operation.
2Ease of operation
If the control box is tilted upward for operator access, then ease of operation is improved, but unintended operation of control levers may occur
Solution Approach 1:
The limit switch is pre-positioned to detect the tilted position and automatically apply the counter-action of shutting down power before any unintended operation can occur. The anti-action (power shutdown) is built into the system and activates automatically when the control box is tilted, preventing potential mistakes.
3Reliability
If the safety lever system is improved with additional components, then reliability is improved, but device complexity increases
Solution Approach 1:
The limit switch is merged with the control box assembly, forming an integrated unit. The electrical interlock is combined with the mechanical tilting mechanism, so that one component (the limit switch) performs multiple functions: detecting position, controlling power, and preventing unintended operation, thereby reducing overall system complexity.
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 solution effectively prevents unintended descending of the control box, promoting safer tilting and reducing the likelihood of equipment malfunctions caused by operator mistakes, thereby enhancing operational safety and reliability.
Implementation Method 1
a spring bracket hinged equally at the hinge axis below the rotating bracket... After the tilting is finished, the spring bracket is suspended on a suspension end
Implementation Method 2
a limit switch is installed on a control box as one body. Thus, when the control box tilts as a result of the rotation of the tiling device, the limit switch also moves along the tilting angle and is guided by a limit holder disposed at a predetermined distance away. In this manner, the limit means can apply or shunt (i.e., short-circuit) the power.
Data Source
AI summary
The present invention relates to a safety lever system in a cab of an excavator, which is capable of preventing an unintended descending of a control box without the operation of the safety lever, and promoting a safer tilting of the control box through a limit means that controls the power application/short-circuit. According to the present invention, if the operator tilts the control box to get in or get out of the cab, the safety lever system shunts (i.e., short-circuit) the power of the control lever or the control box. Therefore, the possibility of malfunction of the excavator due to the miss-operation of the operator is very slim, and the control box cannot be returned to its original position unless the operator operates the safety lever again. This structural improvement of the safety lever eliminates a possibility of the malfunction of the excavator due to the operator's mistake, and markedly increases the reliability of the excavator.