The cable crane itself is two large towers, between which a rope is attached. This rope plays a supporting role in this design. A trolley moves to it, to which a gripping mechanism is attached in the form of a hook or a grab.
General description of the installation
If we talk about the general design of cable cranes, then it is very simple. Due to this, they are considered very reliable. The greatest distribution of such equipment was at construction sites. Most often used during the construction of dams, bridges and locks. Among the main structural elements are the following details:
- Undercarriage. She has support rollers. The grooves of these devices are suitable in diameter for the crane rope.
- The cable crane has a trolley for lifting loads. It is necessary in order to lift loads in the vertical direction.
- There is a traction winch. The main purpose is to move the undercarriage.
- A hook or grapple is used as a gripping mechanism.
As for modern models, then most often they also have a cabin. From it, the operator can control this unit. Most often, such a cabin at a cable drum crane is located approximately at a height of 20 to 25 meters. The height is calculated from the lower reference points of the installation. Although it is important to note here that, in addition to controlling from the cab, such a device can also be controlled remotely. Most often, this control method is used if the construction site has poor visibility.
Crane classification
Cable cranes are divided into two main types according to their mobility.
The first type is fixed installations. The supporting elements of the towers in this case do not move, since they are installed on the foundation. In this case, all operations on the movement of goods should be carried out only under the rope of the device. As for the second type, mobile, the supporting element of both towers or one can move along paths that are arranged in advance. Thus, it is possible to significantly expand the working area of the device.
Types of Fixed Cranes
Fixed cable overhead cranes can be divided into several classes.
- The simplest type is stationary. In this case, the supporting elements of both towers are attached most rigidly. In this case, the carrier rope will maintain a constant position and will not move anywhere during the movement of the trolley. Thus, the working area is very narrow.
- The next variation is towers with deflecting masts. In this case, the supports may swing laterally. And the rope is able to move about 6 degrees under the action of the cart. This helps to increase the range of the working area of the crane.
- Crane with side guy. In this case, the mast rolling angle can be increased to 8-12 degrees, which further increases the working area. The supporting towers in this case are installed on the foundation, and in addition, they have winches and tackles on both sides. Thanks to a tension or release of polyspast and the angle changes.
- The last type of towers are boathouses. In this case, we mean the connection of several cranes on a common support, but at the same time with individual elements (drives and trolleys). They can be operated separately. The working area of this type of fixed crane is the widest.
Mobile devices
As for the mobile types of cranes, they are divided into 3 categories:
- The first view is called parallel. In this case, both support towers move synchronously along pre-laid tracks. The latter can only be straightforward. Thus, a working area of a rectangular type is obtained.
- The second type is radial installations. In this case, one tower is completely stationary, and around it one or several others can move along ring paths. In this case, the working area will look like a sector.
- The last view is a circular type. In this embodiment, both towers will move along circular paths.
Equipment specifications
Among the main characteristics of cable cranes are the following: lifting capacity, operating speed and height. It is worth noting that the height of the tower is also considered separately, as well as the height by which the load can be lifted.
As for the lifting capacity, naturally, it fluctuates within certain limits, which depend on the type of crane model. As for the limit values, the minimum weight is three tons, and the maximum is twenty-five tons. However, it is worth adding that certain special models can lift loads weighing up to 150 tons. The most common rope span is six meters. In some cases, this value can reach up to 1 km. As for the height of the tower of the cable crane, it can reach 70 meters. As for the lifting speed, then on average it is equal to 2.5 m / s. Cargo cable equipment can move cargo at a speed of up to 6 m / s.
Tests of this type of crane
Before putting into operation, and also then at certain intervals, it is necessary to carry out static tests of the cable crane. To successfully carry out this procedure, it is necessary to install the trolley in the position that will correspond to the greatest deflection of the bridges. For testing, it is necessary to use a load whose weight will exceed the maximum load according to the passport by 25%. The duration of the static tests of cable cranes is 10 minutes.