Constant velocity universal joint

A constant velocity universal joint for transmitting motion between two shafts capable of running at an angle to one another, said joint comprising at least four units each including a spindle with the number of said units being an even number, a roller and a pair of opposed grooves, each roller being slidably and rotatably mounted on a respective one of said spindles and having a part-spherical outer rolling surface, each of said shafts including a member, said pair of opposed grooves of each unit being formed in one of said members and each groove being part-circular in cross-section corresponding to the outer part-sperical surface of a respective one of said rollers and cooperating therewith;

• each of said units having said spindle thereof fixed relative to and mounted for movement with one of the shafts and said pair of opposed grooves thereof fixed relative to and mounted for movement with the other shaft, the longitudinal axis of said spindle being disposed in a plane passing through the axis of said one shaft and obliquely thereto, the longitudinal axis of said pair of opposed grooves being disposed in a plane passing through the axis of said other shaft and obliquely thereto, the angle formed between the longitudinal axis of said spindle and the axis of said one shaft being equal to the angle formed between the longitudinal axis of said pair of opposed grooves and said other shaft, the angular and spatial distribution of said spindles and the pairs of opposed grooves relative to their respective shafts being symmetrical when said shafts are in axial alignment.