Comparison of Two Structural Types—Folding-Arm vs. Telescopic-Arm Hedge Trimmers

　　Vehicle-mounted road hedge trimming machine can be categorized into two structural types: folding-arm and telescopic-arm models.

　　Folding-arm hedge trimmers typically feature a three-section folding arm, powered by a four-cylinder diesel engine directly driving a hydraulic pump. These units are relatively large and heavy, typically exceeding 2.5 tons, requiring medium-duty trucks of 4 tons or more for transport.

　　Telescopic-arm hedge trimmers commonly feature two- or three-section synchronous telescoping structures, with three-section designs being the mainstream. They are generally powered by twin-cylinder gasoline generator sets, resulting in compact dimensions and light weight—often under 1.6 tons. This allows them to be transported using 1.9-ton double-cab panel trucks.

　　Highway maintenance units commonly deploy double-cab panel trucks as work vehicles, capable of both hauling equipment and transporting personnel. Thus, the lightweight design of hedge trimmers is critically important.

　　The primary distinction between these two trimmer types lies in performance. The folding-arm structure has inherent limitations:

　　1. Due to its long thread length and multiple joints, overall rigidity is insufficient. Significant vertical vibration of the blade carriage leads to uneven trimming.

　　2. Complex operation and difficult positioning. Coordinating three hydraulic cylinders is required to position the blade carrier precisely. Adjusting any single cylinder affects the blade carrier's distance, height, and angle.

　　3. Time-consuming obstacle avoidance severely impacts operational efficiency. Since hedge trimming often requires maneuvering around obstacles (e.g., kilometer markers), retracting and re-extending the folding arm necessitates adjusting all hydraulic cylinders. Thus, the speed of blade carriage repositioning significantly affects productivity.

　　4. Powered by a bulky, heavy, and noisy four-cylinder diesel engine, it suffers from high failure rates and complex maintenance.

　　5. The cutting deck relies on a hydraulic motor as the primary power source. Its low rotational speed results in weak cutting capability and extremely low trimming efficiency. It cannot handle dense or thick hedges, such as purple locust trees.

　　If rotational speed is increased during design, hydraulic oil temperature rises rapidly, preventing prolonged continuous operation. Generally, the machine must be shut down when hydraulic oil temperature reaches 70°C.

　　6. The machine's heavy weight requires a medium-duty truck for transport, making it unsuitable for highway operations and incurring excessive costs.

　　In contrast, our company's GLC series telescopic boom hedge trimmer offers the following key advantages:

　　1. Lightweight and compact design with a total weight of only 1600kg. Easy to load/unload and transportable using a dual-row panel light truck, making it particularly suitable for highway maintenance units' vehicle configurations.

　　2. Yantai Fangcheng Machinery's patented composite rotating blade holder employs two circular saw blades as cutting tools, achieving significantly higher efficiency than straight blade holders. It can cut branches up to 15cm thick. This makes it one of the few models currently capable of handling dense, thick hedges and branches.

　　3. The machine is equipped with an emergency lift-back mechanism. Should the power system fail during operation, the equipment can be manually retracted for immediate return to base for repairs.

　　4. The control system incorporates proactive safety features: the main motor cannot start when the cutter head is outside the operational range. Once the main motor is activated, the cutter head cannot rotate beyond the operational zone, preventing accidents caused by accidental remote control activation.

　　5. The microcontroller-integrated control system offers high reliability with low heat generation, preventing overheating shutdowns common in similar products due to electrical system heat buildup.

　　6. This telescopic-arm side-leveling trimmer features dual booms, enabling simultaneous operation of both cutting heads for concurrent top and side trimming. When trimming median strips on passing lanes, it halves lane occupancy time and doubles efficiency.

　　7. The three-section telescopic arm offers superior adaptability, meeting long-distance right-slope trimming requirements while minimizing lane occupancy width during median strip trimming.

　　Baoqing Li

　　Dep. of Technology

　　baoqing@equationtec.com