The extended hedge trimmer is a garden machinery designed specifically for trimming tall hedgerows. The design concept mainly considers the following aspects:

1. Body structure: The body of the extended hedge trimmer needs to be long enough to reach tall hedgerows. At the same time, the body needs to be stable to ensure the accuracy and safety of trimming operations.

2. Trimming tools: The tools of the hedge trimmer need to be sharp and durable to ensure the trimming effect. Meanwhile, the cutting tools need to be designed to be replaceable so that they can be easily replaced in case of tool wear or damage.

3. Power system: Extended hedge trimmer usually requires electric drive, so a stable power system needs to be designed. The power system needs to have sufficient power to ensure the operational efficiency of the trimmer.

4. Operating system: The operating system of the extended hedge trimmer needs to be simple and easy to use, so that operators can easily control the trimmer. The operating system needs to include functions such as control switches, speed adjustment, and steering.

5. Safety system: The safety system of the extended hedge trimmer needs to be improved to ensure the safety of the operators. The security system needs to include functions such as scissor locking, overload protection, and automatic power-off.

Overall, the design concept of the extended hedge trimmer is to optimize various aspects such as the body structure, cutting tools, power system, operating system, and safety system to meet the needs of trimming tall hedgerows and improve pruning efficiency and safety.