Abstract: A bed having an array of cylindrical support members supported by a main frame to support a mat, such that the support members are spaced apart from each other in the transverse direction of the bed and such that the support members are rotatable, and a device for rotating the support members in rolling contact with the mat, for changing areas of contact of the mat with the support members to thereby change areas of contact of the user with the mat for promoting blood circulation in a portion of the user in contact with the mat.

Abstract: Method and apparatus for rolling a cylindrical blank in pressed contact with shaped rolling or die faces of rolling dies to generate, on the periphery of the blank, plural teeth corresponding to a profile of the die faces of the dies. The blank is rolled bidirectionally on the die faces of the dies, first in one of opposite directions and subsequently in the other direction. The blank is fed along its axis of rolling while it is rolled bidirectionally, to push the same between the dies for axially progressive rolling engagement thereof with the die faces. The rolling dies may be of reciprocating flat type or rotating cylindrical type. The feeding motion of the blank may be temporarily stopped upon a temporary stop of the rolling movements of the blank at the end of a first movement thereof in one of the opposite directions.