Constant velocity universal joint

A constant velocity universal joint comprising two shafts, said shafts having respective opposed ends and respective part-cylindrical recesses formed in said opposed ends of said shafts, said part-cylindrical recesses having respective axes which intersect at a geometrical centre of said joint, two spiders, each said spider including an outer portion of part-cylindrical shape, said outer portion having an axis and being slidably received in a respective one of said part-cylindrical recesses, and an inner portion affording a part-cylindrical surface having an axis, said axis of said part-cylindrical surface of said inner portion extending perpendicular to said axis of said outer portion, a central member having a cylindrical surface having an axis, the cylindrical surface of said central member facing said part-cylindrical surfaces of said inner portions of said two spiders, said axes of said part-cylindrical surfaces of said inner portions of said two spiders being coincident and constituting an axis of said central member passing through said geometrical centre, and coupling means connecting said two spiders and arranged to transmit rotational movement of each of said two spiders about said axis of said central member to the other of said two spiders such that said two spiders are constrained to rotate through equal distances but in opposite directions about said axis of said central member.