The 360° rotation function of a log grapple relies on a rotary motor and a balance valve. The balance valve's one-way function allows fluid to flow at very low pressure into the hydraulic actuator to rotate, then locks the circuit, maintaining the load position. The balance valve's hydraulic throttling function controls the throttling opening by controlling the pressure at the pressure port, thus allowing the load to drop smoothly at the required speed. The balance valve's overflow function opens when the inlet pressure exceeds the set pressure due to external force or expansion, preventing damage to the hydraulic motor or oil seals due to overpressure and providing overload protection.
The design of the rotation mechanism is also crucial. Common optimization designs include using new worm gear or reducer designs for smoother operation. Braking pads improve the accuracy and lifespan of rotation stopping. Specialized rotary gears are used to extend product life and reduce maintenance costs.
In log grapple hydraulic systems integrating more functions (such as chainsaws), a series of key technological improvements exist to enhance reliability and safety. For example, a check valve is installed between the motor drain and return ports to prevent damage from excessive motor back pressure, and a check valve is used to prevent the saw motor from reversing. An innovative application of an overflow throttle valve is used to achieve a stable saw blade feed speed, and a safety valve is added to provide safety protection during saw advance. A hydraulically controlled overflow valve is used to lock the chainsaw in the non-working state to prevent it from falling automatically.