Abstract: The invention is directed to an attachment assembly for securing two membrane strips loosely laid parallel to each other and overlapping with each other. The attachment assembly incorporates a load distribution plate having short and long lateral lever-arm extension means and a bore hole defined in the plate, a fastener screw operatively connected to the load distribution plate through the bore hole, and a fastener screw operatively connected to the load distribution plate through the bore hole. The short and long lateral lever-arm extension means of the plate extend in directions relative to the fastener screw. The short lateral lever arm extension means operates with forces due to the billowing of the roofing membrane so as to uplift a long edge of the load distribution plate and thereby introduce a first force corresponding to a lever arm ratio at the long lateral lever arm extension means at an area opposite to the bore hole.

Abstract: An apparatus for contactless sealing of an opening against emerging or entering gas employs at least one barrier gas jet which is divided in the vicinity of its longitudinal axis. In the two sub-jets adjoining the dividing plane two different gases flow out, the concentration of the two gases changes abruptly at said dividing and separating plane so that a very reliable sealing is achieved.

Abstract: An artificial heart valve consists basically of a valve ring and a valve flap in the form of a disc which is pivotally mounted eccentrically in the valve ring, the external circumferential surface of the valve flap cooperating with the internal contour of the valve ring to form a sealing line extending round the circumference of the valve flap. Manufacture of the heart valve can be substantially simplified if the valve ring is obtained by a slightly oblique cut through a hollow cylinder and the valve flap by an oblique cut made at a slightly larger angle through a solid circular cylinder which constitutes the core of the hollow cylinder.