Abstract: A mandrel of sponge rubber or gel has a tension element for withdrawing the mandrel from a graft tube grown from living tissue. In a first embodiment the tension element comprises a strip of cloth embedded in a sponge rubber mandrel. In a second embodiment the tension element comprises a rubber tube containing the sponge rubber and in a third embodiment the tension element comprises a rubber tube containing a gel. The mandrel assembly includes cloth reinforcing tubes surrounding the mandrel.

Abstract: A fluid-mechanical drive for a press brake incudes two lever members, pivotally connected between their opposite ends to two corresponding end frame members of the press brake. A pair of hydraulic cylinders pivotally connect one end of each lever member to the upper blade at spaced positions,. The opposite end of each lever member is mechanically connected to the upper blade so that upon simultaneous extension of the two fluid cylinders, a direct downward force is applied to the upper blade at two spaced positions along the blade by such cylinders and a downward reaction force is applied through the lever members and mechanical means to the upper blade at two other spaced positions along the blade to drive such blade downwardly through its working stroke into coaction with a lower blade. In one embodiment, the mechanical means are link members, each pivoted at one end to the upper blade and at the other end to a lever member.

Abstract: A loader and unloader for a plate roll machine has an extensible boom extending generally horizontally over the plate rolls of the machine from a stationary support frame to which the boom is pivoted at one end for vertical movement over the rolls. The boom telescopes through the action of a hydraulic cylinder from a retracted position in which the free end of the boom overlies the plate rolls to an extended position in which such free end extends outwardly beyond the plate rolls. Additional fluid cylinders pivot the boom vertically. A plate support carriage is pivoted to the free end of the boom for fore-and-aft tilting movement. The carriage has one or more rollers extending lengthwise of the boom for engaging and supporting a rolled plate at its upper inside surface. The boom is retracted and positioned vertically for supporting the plate as it is rolled in the plate rolls.