Grab loader: description and types
At the moment in the world of special technology there is a huge number of different loaders. And today we are not talking about classic forklifts that load pallets. Everyone knows about them. And we will pay attention to loaders with grab grab. This technique looks quite different. She also has a completely different principle of operation (compared to fork counterparts). What does a grabber loader look like? Photos, the principle of his work and purpose - later in our article.
This name comes from the German word "Greyfen", which literally translates as "grab". This unit is a lifting device, which is installed on cranes, excavators, as well as on tracked and wheeled tractors. Very often you can find a grab loader on the basis of MTZ. This technique is used for loading long timber and bulk cargo.
Externally, the grab loader is a conventional tractor or excavator, at the end of which there is a large iron bucket. It is he who joins the crane and captures various materials for loading and unloading.It should be noted that such loaders are used not only for bulk cargo and timber. Also, the grapple can dig deep pits, raise rocks and break concrete (but in the latter case, a special, powerful grab with strong legs is needed).
The main parameters of the grabber loader are bulk density, which is measured in kilograms or tons per cubic meter, and carrying capacity. The latter is denoted by the letter Q.
This parameter includes the weight of the grab and the load itself. The scaling ability of the aggregate depends on the ratio of Q. There are four classes of grab loaders:
- Very light. Their bulk density ranges from 400 to 630 kilograms per cubic meter. Usually such loaders are used for coal dust and lime. The load index is 0.37.
- Lungs. These units are used to load dry slag, alumina, chalk, medium gravel and coal of different grades. Bulk density ranges from 800 to 1000 kilograms per cubic meter. The load index is 0.4.
- Average. Used for small clay, alabaster, and limestone.Also, this type of tractor (grab loader of the middle class) can be used to transport broken brick, large crushed stone and cement. The bulk density of the unit is about two tons per cubic meter. Load capacity - 0.42 Q.
- Heavy. These loaders are used for hard rock. Load capacity - 0.45 Q. The bulk density varies from 2.5 to 3.2 tons per cubic meter.
Regardless of the type, the grab loader (including home-made) must have the protection of the ropes against chafing with material that is caught by the bucket.
Grader blocks are installed in such a way as to exclude the arbitrary loss of the ropes and their disclosure.
There are several types of these loaders:
- Rope. In turn, are divided into single and multi.
- With a hard suspension. Such units are driven, as well as double and maxillary.
Below we consider each type of loader in more detail.
Let's start with monocable units. Such loaders possess replaceable load gripping devices. The grab is hung on the hook clip.The rope of the unit is simultaneously closing and lifting. The main feature of such devices is the presence of a lock that connects the traverse with the clip. The latter is made with blocks of polyspast. Typically, single-rope units have a bulk density of 500 kg to 2 tons per cubic meter.
Among the advantages of such devices can be identified versatility. Due to the fact that the grab is hung on the hook, it can be installed on any tractor, excavator and even a crane. But the single line units have a number of drawbacks. This is a small height of volume (usually it does not exceed two and a half meters) and manual control of the opening of the jaws of the apparatus.
As for the two-cable, in such loaders the jaws are connected to the lower traverse with the help of a thrust with a head. On the latter is a hoisting rope that lowers and lifts the device. Driven by such a loader winch. It can be driven by a single engine or by a clutch. To increase the cutting force, on the edges of both jaws, a rope is pressed into the chain hoist. Blocks with clips last mounted on the head and the lower traverse.
Among the advantages of two-cable devices, it is worth noting the high capacity capacity. At one time, this loader can scoop bulk material from two to twenty cubic meters. All work is done automatically. At the time of closing the jaws, the winch works itself. Among the drawbacks of such loaders it is worth noting the inability to quickly replace the grab.
Heavy Duty Lift Trucks
Such units are used for scooping material in large quantities. Used for unloading the holds of ships and wagons.
This grab is mounted on a hook clip with a single drum winch. In the design of the unit has a top head (it has a drive installed) and jaws fixed with hinges. The drive can be of different types:
The mechanism for closing the jaws in such units is built into the design of the grab and is installed on the traverse or lever-screw system. To power the drive mechanism you need an electrical cable. In some models, the drive circuit is located on the upper traverse. These grabs center of gravity is shifted slightly up.Among the advantages of using loaders with a hard suspension is worth noting the compact design, as well as lifting height. Among the minuses is the instability of the grapple when scooping material from the slope. In this case, the center of gravity of the device is significantly shifted.
Also note that in the production of used and multi-maxilla grab loaders. They have from four to eight devices to capture cargo. Typically, such devices are used for hard-to-dispense material. The loader jaws are crescent-shaped and fixed to the lower cylindrical traverse by means of hinges. The working angle of the paws is from 45 to 120 degrees. By the way, multi-max grabs are also used for loading timber. However, so that the feet do not damage the trunk of the tree, they have a more flat shape.
So, we figured out what a grabber is. As you can see, this technique is used in different industries, has a different shape and technical characteristics. But they have one task - to load or unload a particular type of material in the right amount.