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| Illustration 1 | g01398341 |
(1) Hydraulic extenders (2) Control stations (3) Walkways | |
This presentation covers the AS2302 VERS-A-MAT Screed with the electric screed plate heating system. This screed is equipped with front mounted extenders.
Asphalt pavers consist of two basic sections that are the tractor and the screed. The tractor receives the asphalt and the tractor delivers the asphalt to the screed. Also, the tractor tows the screed. In some applications, the tractor also pushes the delivery truck. The screed spreads the asphalt and the screed partially compacts the asphalt in order to form the mat.
The tractor tows the screed via the tow arms which are attached to both sides of the tractor and the screed. The point at which the tow arms connect to the tractor is called the tow point. Electrically controlled hydraulic cylinders raise and the cylinders lower the tow point. The position of the tow point affects the screed's angle of attack. This angle of attack impacts the amount of material that passes under the screed.
Screeds that are equipped with hydraulic extenders (1) enable variable paving widths. The extenders are mounted in front of the main screed or the extenders are mounted to the rear of the main screed. Each screed design has unique characteristics.
Screeds with rear mounted extenders tend to be more rigid at wider paving width than screeds with front mounted extenders. Therefore, screeds with rear mounted extenders may have a slight advantage in applications which require wide paving widths. Although, these screeds require more mix in order to maintain the proper head of material. This fact gives screeds with front mounted extenders a slight advantage on jobs that require frequent changes in paving width.
The type of screed a contractor chooses is dictated somewhat by the typical application. However, this largely depends on the contractor's choice.
Vers-A-Mat Screeds with the electric screed heating system are equipped with five control stations (2). One station is at either side of the main screed and one on the end of each screed extender with a fifth station at the center of the main screed for electric heat control. Walkways (3) that are along the main screed and the extenders allow the operator to move from one side of the screed to the other without walking on the newly laid mat. Using the walkways to ride on the screed when roading or transporting the machine is not recommended.