Hydraulic Clamp Force Circuit for Fast Lift Truck Closure
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Solution Overview
Problem
Hydraulic control systems for lift truck attachments face challenges in achieving high-speed closure of clamps without damaging loads, as low initial pressures limit productivity and the use of flow dividers restrict closing speed and force control.
Innovation Solution
A hydraulic control circuit that alternates between hydraulically linked and unlinked configurations for hydraulic actuators, allowing high-speed clamp closure without flow dividers, by selectively connecting and disconnecting fluid pressure to optimize clamp force and speed during load engagement and release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high closing pressure is used to achieve high-speed clamp closure, then closing speed is improved, but clamp force against the load becomes excessively high causing load damage
Solution Approach 1:
The hydraulic control circuit dynamically switches between two operational modes: a first mode during initial closure where clamps are hydraulically linked and operate at high pressure for high-speed closure, and a second mode after load contact where clamps are hydraulically unlinked and pressure is reduced to prevent load damage. This dynamic transition resolves the contradiction between high closing speed and load protection.
Solution Approach 2:
The system performs preliminary high-pressure closure to bring clamps into contact with the load, then transitions to low-pressure operation once contact is made. The load-weight sensing mechanism detects load contact and triggers the mode transition, ensuring high-speed closure is achieved without sustained high clamp force that would damage the load.
2Object-affected harmful factors
If low initial pressure is used to prevent load damage, then load protection is improved, but closing speed is reduced limiting productivity
Solution Approach 1:
The hydraulic control system employs periodic action by alternating between high-pressure closure phase and low-pressure holding phase. During the closure phase, high pressure enables fast approach; after load contact detected by the sensing mechanism, the system transitions to low-pressure operation to prevent damage, thus achieving both high productivity and load protection.
3Stability of the object's composition
If flow dividers are used to coordinate clamp movement, then synchronized movement is improved, but closing speed is limited and system complexity increases
Solution Approach 1:
The invention extracts and eliminates the flow divider component from the hydraulic system. Instead of using flow dividers to coordinate clamp movement, the system uses a hydraulic control circuit with load-weight sensing that coordinates clamps by detecting load contact and switching between hydraulically linked and unlinked configurations, thereby achieving synchronization without the speed-limiting and complexity-introducing flow divider.
Solution Approach 2:
The load-weight sensing mechanism acts as an intermediary that coordinates clamp operation. Rather than using flow dividers to mechanically balance clamp movement, the sensing mechanism detects load contact and triggers electronic/hydraulic control signals that coordinate the transition between closure and holding phases, enabling faster and more flexible synchronization.
4Speed
If complex hydraulic control systems with selectable relief settings are used to provide high-speed closure with low initial clamp force, then closing speed and load protection are improved, but device complexity increases
Solution Approach 1:
The hydraulic control system is self-regulating through the load-weight sensing mechanism. The system automatically detects when clamps contact the load and autonomously transitions between high-pressure closure mode and low-pressure holding mode without requiring manual intervention or complex external control systems, thereby achieving high-speed closure with load protection while minimizing 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
Enables efficient high-speed clamp closure and reduced load damage by adjusting clamp force control, improving productivity and reducing the need for complex hydraulic systems and flow dividers.
Implementation Method 1
Hydraulic control systems for clamp attachments need to provide a sufficient lateral force to securely grasp the load... hydraulic control systems typically include some type of load-weight sensing mechanism along with a control system that regulates gripping force by gradually increasing gripping fluid pressure
Data Source
AI summary
A hydraulic control circuit operable to selectively hydraulically link first and second hydraulic actuators and to bypass that hydraulic link.