Getting started with such a technique is best done with concepts. The crane is a machine that is designed to lift various kinds of cargo. It consists of a crane manipulator unit (CMU). This device is installed either stationary or on a specific running device.
General Description of the CMU
A crane manipulator installation is understood to mean a lifting device, which includes boom working equipment, load-gripping elements, a control system, and also a support frame. It is also worth noting that the crane does not have a hydraulic organ.
Hydraulic manipulators are actively used as a mechanism for lifting goods. Most often, an example of the operation of this device can be seen during the work of garbage trucks, timber trucks, metal carriers, etc. In other words, for those machines whose main purpose is the handling of cargo.
If we consider the design of the crane, it can be divided into two parts. The first is longer, the second is shorter, but it has a telescopic device. Due to this design, quite often there are problems with the transportation of such equipment, since it does not come out of the way to direct it. For this reason, they are placed in such a way that the boom is directed either forward or backward from the cab.
Z-shaped models
Naturally, there are various models of the crane, one of which is the Z-design. This type differs from the usual arrangement of the second part of the boom, which is superimposed on top of the first part. Thus, the load capture is also at the top. This significantly saves space, which means that it becomes much more convenient to transport them. But there are also drawbacks, one of which is that such equipment has a rather small load moment, which greatly narrows the scope of its application.
Technical parameters of the machine
These machines have a lot of diverse technical characteristics that affect not only the cost of the device itself, but also, for example, the services of a crane. These parameters include the following:
- the maximum and minimum distance that the boom extends or retracts;
- load capacity determined at maximum and minimum distance;
- there is also the value of the load moment of the boom, determined in the same two positions;
- height of raising and lowering the object;
- there is also a value for the minimum turning radius of the entire crane;
- quality and performance of the suspension.
These technical parameters apply to the entire installation. However, there are some design features of the KMU boom itself, which every operator of a crane needs to know.
- Cross sectional shape. This form most often has four, five, six or eight faces. The larger their number, the stronger the arrow is considered.
- It is very important to understand the telescopic boom extension system. It can be either arbitrary or sequential.
Description of classes and carrying capacity
The following three features are used to classify all CMUs:
- the capacity of the installation or its load moment;
- type of boom used on this unit;
- type of support for installation.
The following is a more detailed classification for each parameter. If we talk about carrying capacity, then there are three types:
- micromanipulators - lifting capacity up to one ton;
- medium installations - from one to ten tons;
- all plants with an indicator above 10 tons are considered heavy.
However, it is worth paying attention to the fact that the mass of the lifted load for such devices is a subjective characteristic. The reason for this was the fact that it is impossible to trace the dependence on the departure of the arrow.
Cargo moment
The load moment for a truck crane or any other is a characteristic that is a product of the lifting capacity and the boom of the device. This parameter is measured in tons per meter (tm). Although some documents may indicate a value in kilonewtons per meter (kNm). It is also important to note that there is no specific table, for example, with fully established values. Therefore, most often the classifications of the largest companies in this area are taken as the basis. For example, when calculating the services of a crane, the Austrian company Palfinger divides its equipment into the following classes:
- light types of CMU - up to 3.9 tm;
- from 4 to 29.9 tm - this is the average CMU;
- from 30 to 150 tm - heavy CMU.
But, for example, the Swedish Hiab adheres to a completely different distribution. Light models - up to 10 tm, from 10 to 22 tm - medium, and everything above 22 tm is a heavy class.
From all this it follows that the carrying capacity or load moment is one of the most important technical characteristics, which at the same time does not have a single calculation table. Each manufacturer is guided by its own species division system.
Boom equipment
Another major element of the entire structure is the arrow. According to the type of suspension, this device can be of two types - articulated, considered rigid, or rope, which is flexible. If the boom device has a cable version, then the crane operator grabs the load with a hook, which is located at the end of the boom. If the execution is rigid, then the cargo capture body is mounted on the boom head with a hinge.
It is also worth highlighting the external component of the boom. It can be Z-shaped or L-shaped. These names were given to devices because of their appearance, which they have in the folded position.
If we talk about the design of the first type, then it is considered a European model, since it is these manufacturers that most often use this method. This type of boom allows it to fold into several knees, which can significantly save space and place such structures behind the car cab. When unfolding the CMU of this type, it is obtained across the frame of the car.
The L-shaped type is most often used by Japanese, South Korean and North American designers. In such a CMU, the arrow has a direct telescopic view. A cable is used as a suspension for a hook.
Application of automobile cranes
A truck mounted crane is a truck that is equipped with a CMU. The greatest use of this technique has been in the construction industry. It is used to transport various building materials - concrete products, pallets with bricks, etc. In addition, such equipment can be used as a replacement for a full-fledged crane, if we are talking about the construction of low-rise houses. It is also successfully operated during the repair and construction works of various types, during landscaping or road works.
As for the reviews on this technique, they are very different and greatly depend on the chosen model. For example, the model company Amco Veba. Owners characterize it as a convenient car with a good carrying capacity. Among the advantages also stand out is that the cargo does not swing during transportation, and there is also the possibility of installing additional equipment. Of the minuses, the absence of a winch, as well as difficulties with lowering the load to a precisely defined place, if it is located above the car itself, are distinguished.