Abstract: A universal joint comprises a driving gear and a driven gear each provided with a respective crown gear cluster, and a slotted casing confining the driving gear and the driven gear in meshing engagement. The casing comprises a slot through which the driven gear projects and along which the driven gear may be moved angularly from a first position in which the driving gear and driven gear are in-line, and a second position in which the driving gear and driven gear are substantially at right angles to one another. A guide element is captive on the driven gear and disposed within the casing, and rides along a channel formed in the casing. The guide element guides the driven gear in movement from the first position to the second position.