There are various types of working devices for hydraulic excavators (up to over 100 types), and currently, backhoes and crushers are widely used in engineering construction.

反铲结构

Backhoe structure

铰接式反铲式单斗液压挖掘机常用的结构形式，动臂、斗杆和铲斗等主要部件彼此铰接，在液压缸的作用下各部件绕铰接点摆动，完成挖掘提升和卸土等动作。

The commonly used structural form of articulated backhoe single bucket hydraulic excavators is that the main components such as the boom, bucket rod, and bucket are hinged to each other. Under the action of the hydraulic cylinder, each component swings around the hinge point to complete excavation, lifting, and unloading actions.

斗杆油缸；2-动臂；3-液压管路；4-动臂油缸；5-铲斗；6-斗齿；7-侧齿；

Stick oil cylinder; 2-Boom; 3- Hydraulic pipeline; 4- Boom oil cylinder; 5- Bucket; 6- Bucket teeth; 7-side teeth;

连杆；9-摇杆；10-铲斗油缸；11-斗杆

Connecting rod; 9- Rocker; 10- Bucket oil cylinder; 11- Stick

动臂

Boom

动臂是反铲的主要部件，其结构由整体式和组合式两种。

The boom is the main component of a backhoe, and its structure consists of two types: integral and combined.

整体式动臂

Integral boom

整体式动臂的优点是结构简单，质量轻而刚度大。其缺点是更换的工作装置少，通用性较差，多用于长期作业条件相似的挖掘机上。整体式动臂又可分为直动臂和弯曲动臂两种。其中的直动臂结构简单质量轻制造方便，主要用于悬挂式挖掘机，但它不能式挖掘机获得较大的挖掘深度不适用于通用挖掘机；弯动臂是目前是目前应用广泛的结构形式，与同厂都得直动臂相比可以使挖掘机有较大的挖掘深度，但降低了卸土高度，这正符合挖掘机反铲作业的要求。

The advantages of an integral boom are its simple structure, light weight, and high stiffness. Its disadvantage is that there are few replacement working devices, which have poor universality and are often used on excavators with similar long-term operating conditions. Integral boom can be divided into two types: straight boom and curved boom. The straight arm structure is simple, lightweight, and easy to manufacture, mainly used for hanging excavators, but it cannot achieve a large excavation depth and is not suitable for general excavators; The curved boom is currently a widely used structural form. Compared with the straight boom used in the same factory, it can provide a larger excavation depth for excavators, but reduce the unloading height, which is in line with the requirements of backhoe operations for excavators.

组合式动臂

Combined boom

组合式动臂有辅助连杆（或液压缸）或螺栓连接而成。上下动臂之间的夹角可用辅助连杆或液压缸来调节，虽然结构操作复杂化但在挖掘机作业中可随时大幅度调整上下动臂者间的夹角，从而提高挖掘机的作业性能，尤其是用反铲或抓斗挖掘窄而深得基坑时，容易得到较大距离的垂直挖掘轨迹，提高挖掘质量和生产率。组合式动臂的优点是，可以根据作业条件随意调整挖掘机的作业尺寸和挖掘能力，且调整时间短。此外他的互换工作装置多，可以满足各种作业的需要，装车运输方便。其缺点是质量大，制造成本高，用于中小型挖掘机上。

The combination boom is composed of auxiliary connecting rods (or hydraulic cylinders) or bolted connections. The angle between the upper and lower booms can be adjusted by auxiliary connecting rods or hydraulic cylinders. Although the structural operation is complex, the angle between the upper and lower booms can be greatly adjusted at any time during excavator operation, thereby improving the operational performance of the excavator. Especially when using a backhoe or grab to excavate narrow and deep foundation pits, it is easy to obtain a larger vertical excavation trajectory, improving excavation quality and productivity. The advantage of a combination boom is that it can adjust the working size and excavation capacity of the excavator according to the working conditions, and the adjustment time is short. In addition, he has many interchangeable working devices, which can meet the needs of various operations and facilitate loading and transportation. Its disadvantages are large quality and high manufacturing cost, which are used on small and medium-sized excavators.