Traction device and apparatus with foldable frame

An apparatus adapted to traverse an area covered with a loose, granular material, comprising:

• a frame having a first side and a second side spaced apart from and opposite the first side, each of the first side and the second side having an upper portion and a lower portion opposite the upper portion;
• and
• a rotatable traction device having a first end, a second end, an outer surface, and a longitudinal axis about which at least some of the outer surface of the rotatable traction device revolves when the rotatable fraction device rotates,
• wherein the first end of the rotatable traction device is connected to the lower portion of the first side of the frame and the second end of the rotatable traction device is connected to the lower portion of the second side of the frame,
• wherein at least a portion of the outer surface of the rotatable traction device between the first end and the second end includes a plurality of spaced apart curvilinear or angularly shaped traction ridges and a plurality of spaced apart curved or angularly shaped valleys, each curved or angularly shaped valley having at least one curved or angularly shaped wall and being between a pair of adjacent curvilinear or angularly shaped traction ridges, thereby forming a plurality of curved or angularly shaped shovel-like elements in the rotatable traction device, each shovel-like element having a leading curved or angularly shaped surface and a confining curved or angularly shaped surface, and
• wherein rotation of the rotatable fraction device results in rotation of the curved or angularly shaped shovel-like elements through at least a portion of the loose, granular material as the rotatable traction device rotates,
• whereby each curved or angularly shaped shovel-like element enfolds all or substantially all of a portion of the loose, granular material bordering the leading curved or angularly shaped surface of the shovel-like element, and the confining curved or angularly shaped surface of the shovel-like element confines all or substantially all of the enfolded portion of the loose, granular material, thereby confining and restricting displacement of all or substantially all of the enfolded portion of the loose, granular material as the apparatus traverses the area.