Abstract: A first object of the invention is to provide a medical device capable of effectively preventing backwards flow of blood.

Abstract: A press die set includes a hollow cylindrical guide bush mounted on a punch holder, a cylindrical retainer received within the guide bush, and a columnar guide post vertically mounted on a die holder and received within the retainer. First right angle grooves are formed on the outer surface of the guide post parallel to a longitudinal axis of the guide post. First planar surfaces are formed on an outer surface of the guide post parallel to the longitudinal axis of the guide post and perpendicular to a radius of the guide post. Second right angle grooves are formed on the inner surface of the guide bush parallel to a longitudinal axis of the guide bush. Second planar surfaces are formed on the inner surface of the guide bush parallel to the longitudinal axis of the guide bush and perpendicular to a radius of the guide bush. Cross roller bearings are positioned between the first and second right angle grooves, and plain roller bearings are positioned between the first and second planar surfaces.

Abstract: The bottoms 225 of circumferential groove 22 are equidistant from the axis of rotation 215 and constitute the sides of the column, the axes of rotation of which are common. The sides 226 and 227 of the circumferential groove 22 are not normal to the axis of rotation 215, and are beveled to form an acute angle to the bottom 225. That is, the sides 226 and 227 of the circumferential groove 22 form sides of cones the axes of rotation of which are common. The width of the circumferential groove 22 becomes widened from the surface to the inside. Resin 26 is coated on the surface of the circumferential groove 22 in such a manner that the coated surface has a substantially constant width. In this embodiment, a nylon type resin is coated with little peeling-off during use of the roller.

Abstract: A sliding bearing assembly for a press die set includes a guide post having at least two external grooves disposed parallel to the post axis, each of which has two flat surfaces oriented at 90 degrees to one another. A guide bushing is slidably mounted on the post by guide blocks and a retainer assembly. The guide bushing includes a number of guide blocks equal to the number of grooves in the guide post, and each has a groove opposed to a corresponding groove in the post. The retainer assembly, which is positioned within the guide bushing, includes at least two cross roller bearings, one for each groove on the guide post, mounted on a generally circular frame. The roller bearings are mounted on the frame with the axes of the rollers at such an angle relative to the plane of the frame that the rollers run along the aligned opposed grooves in the guide post and guide blocks.