I believe many friends in the mechanical industry are familiar with the use of extended arms. In municipal construction, subway transportation improvement, sewer renovation, river cleaning, and other fields, a large amount of engineering machinery and equipment are required, and standard excavation machinery cannot complete specialized engineering operations. Therefore, at this time, extended arm excavators use ultra long boom and ultra long bucket to showcase their power, which can be used in dredging, bank protection Under conditions limited by the ground environment, such as slopes and subway construction, they exert tremendous power.

一般常见的有以下几个应用领域：

There are generally several common application areas:

1.两段式加长臂：使用范围相对较大，但是他的主要功能也即是为了提升挖掘半径，在清理河道，填海造地，地铁出入口开挖，人行地底隧道，还有高速公路防护墙修整，一般住宅输送一下水泥等等。也有人用他前置破碎锤作用于房屋拆迁的，不过比较危险。两段式加长臂一般10-26米区间改装比较多。

1. Two section lengthening arm: The scope of use is relatively large, but its main function is to increase the excavation radius, such as clearing river channels, filling the sea to create land, excavating subway entrances and exits, underground pedestrian tunnels, repairing highway protective walls, and transporting cement to general residential areas. Some people also use his front crushing hammer to act on house demolition, but it is quite dangerous. Generally, there are more modifications in the 10-26 meter section of the two-stage extension arm.

2.三段式加长臂：或者多段式加长臂，主要应用于高层建筑的拆迁，前置破碎锤或者液压钳。20-28米内使用者比较多。

2. Three section extension arm: or multi section extension arm, mainly used for demolition of high-rise buildings, with a front crushing hammer or hydraulic pliers. There are many users within 20-28 meters.

3.滑臂或者内伸缩臂：主要为了回转半径很小，但是挖掘深度要求很高的工况设计，一般会前置贝壳挖斗（贝形斗）。滑臂垂直挖掘深度一般为10米，内伸缩臂垂直挖掘深度一般在26米以内。

3. Sliding arm or inner telescopic arm: mainly designed for working conditions with a small turning radius but high excavation depth requirements, usually a shell digging bucket (shell shaped bucket) is placed in front. The maximum depth for vertical excavation of the sliding arm is generally 10 meters, and the vertical excavation depth of the inner telescopic arm is generally within 26 meters.

4.打桩机加长臂：大小臂平直，前置弯臂2.6米左右（主要是为了与振动锤连接是便与阀块和管路的安装）及震动锤，应用于修建公路铁路或者埋设管道的时候打拔钢板桩。

4. Pile driver extension arm: The large and small arms are straight, with a front bending arm of about 2.6 meters (mainly used to connect with the vibration hammer and facilitate the installation of valve blocks and pipelines), and the vibration hammer is used for driving and pulling steel sheet piles when building highways, railways, or burying pipelines.

5.抓木机、抓料机装卸煤机加长臂：更多的时候为了装卸火车或者汽车而设计，一般大臂7.6米，小臂5-6米.前置抓木器、抓钳器或者贝壳挖斗。

5. Wood grabbing machine, material grabbing machine, and coal loading and unloading machine with extended arms: more often designed for loading and unloading trains or cars, usually with a large arm of 7.6 meters and a small arm of 5-6 meters. Front mounted wood grabbing machine, pliers or shell excavator.