Abstract: A rotary support device comprises an annular upper member and an annular under member which are so arranged that their inner or outer peripheral walls overlap each other with a small clearance formed therebetween. The overlapping peripheral walls are bent toward each other to form a pair of retaining portions which are rotatable relative to each other. A plurality of steel balls held spaced apart equidistantly by a retainer are rollably provided between the two members.

Abstract: A device including a stretchable assembly (2) of pairs of intersecting arms (3) and (4) pivoted to each other at the intersections for raising or lowering a table (5) mounted on the upper ends of the arms. The stretchable assembly (2) is vertically expandable or collapsible by a unit (6) of a cylinder (61) for advancing or retracting a piston rod (62), a pump (63) and an oil tank (66) mounted on a base plate (7) and fixed to a frame (1) at the lower end of the stretchable assembly (2). The piston rod (62) extends substantially upward from the cylinder (61) and is connected at its forward end to lower portions of the arms (3). The piston rod (62) intersects the arms (3) substantially at right angles thereto when the stretchable assembly (2) is in its collapsed position.