Log grapples are accessories for excavator working devices, mainly classified into mechanical log grapples and rotary (hydraulic rotary) log grapples based on their working principle. Mechanical log grapples can be used without modifying the excavator's piping and hydraulic system, resulting in lower costs. Rotary log grapples require modification of the excavator's piping and hydraulic system to achieve 360-degree rotation, offering easier operation but at a higher cost.
Based on an existing four-jaw log grapple, a hydraulic chainsaw was added to design a log grappling saw integrating log grabbing, handling, and sawing functions.
The hydraulic system of the log grappling saw prevents excessive motor back pressure by installing a check valve between the motor's drain and return ports, uses a check valve to prevent the saw motor from reversing, applies an overflow throttle valve to achieve a stable saw feed speed, adds a safety valve for saw feed safety protection, uses a hydraulically controlled overflow valve to lock the chainsaw in non-working states, and selects low-pressure oil from the saw motor's return port to supply lubricating oil to the chain via a hydraulically controlled check valve. These improvements enhance the reliability and safety of the hydraulic system and enable industrial application.