Carriage with telescopic sliding arms

This type of expandable undercarriages allows for a track variability by means of a simple translation of the boxes. The system in use is based on a male–female coupling, where the male element (sliding arm) is fastened to the boxes, and the female element (sliding seat) is embedded in its frame.

This type of carriage is characterized by the presence of two sliding seats every side.
The cavity dimensions differentiate the sliding seats located on the right-hand side of the undercarriage from those located on the left side. In the same way, the sliding arms fastened to the boxes will have different dimensions, to perfectly match their sliding seats.

The movement to widen or narrow the track is got by means of one oil-pressure cylinder each side. These cylinders are fastened both to the box and to the frame and are protected by steel sheet covers that preserve them when they are extended.
Vertical and horizontal supports made of alloy steel are fastened to the sliding seats and the legs.
Their aim is to create a discontinuity in the materials used in the undercarriage manufacture, to prevent sticking between the legs and the sliding seats in case of long periods of inactivity. If we compare an undercarriage with telescopic sliding arms to other types of undercarriages, we'll immediately notice its higher longitudinal compactness, due to the compenetration of the sliding seats.

On the other hand, this type of undercarriage shows some play between the sliding arm and the sliding seat. These intrinsic characteristics make it suitable to be paired with machines applying a continuous stress to the undercarriage, not to excessively interact with the leg play.
Therefore the undercarriages with sliding arms are paired to augers, cutters or vibrating machines.