Abstract: A process and apparatus for forming a sheet element with a contoured surface from a plane titanium or titanium alloy sheet by hot deep-drawing in a press. The plane sheet is preheated to a temperature of at least 730.degree. C. and transferred to a non-preheated deep drawing tool. The deep-drawing tool is placed in a press for a period of time sufficient for the temperature of the element to be at least 700.degree. C. at the end of the deep-drawing operation. The deep drawn element is transferred to a calibration tool and heated to at least 650.degree. C. for a sufficient time to assume a final shape and allowed to cool to room temperature.

Abstract: A connector including two interfitting tubular elements and a locking ring having at least two staggered rows of locking lugs cooperating with corresponding locking lugs of one of the tubular elements. The locking lugs are inscribed in cylindrical surfaces having different radii, so that when the ring is inserted on the element, its lugs slide effortless on the lugs of the first lug row of the element to a position where the lugs of each lug row of the ring can pass between those of a corresponding row of the element to form a plurality of bayonet couplings which can then be simultaneously locked.