Abstract: A lubricant supply assembly for a universal joint comprises a universal joint, two rotation shafts connected via the universal joint and being capable of being bent relative to one another, ball-and-socket joints secured at the two rotation shafts, and a coupling tube provided at the universal joint for introducing a lubricant from one of the two rotation shafts to the other of the two rotation shafts. The coupling tube is a single tube. The end of the coupling tube is fixed to a ball in one of the ball-and-socket joints while the other end of the coupling tube slidably penetrates a ball in the other of the ball-and-socket joints to protrude from it.

Abstract: A universal joint includes a pair of yokes each having two trunnions projecting radially thereof, and an annular intermediate ring having bearings arranged on two diametrical lines thereof intersecting each other at right angles for supporting the respective trunnions. An annular central cover having a spherical outer surface is fixedly intimately fitted around the intermediate ring. Between the ring and a connecting flange at the outer end of each yoke, a collar is formed on the yoke. A pair of annular side covers each having a spherical inner surface slidable in contact with the spherical outer surface of the central cover each have an outer end portion horizontal in section and fixed to the periphery of the collar. An annular seal member in intimate contact with the outer surface of the central cover is provided at the inner end portion of each side cover. A clearance required for the sliding movement of the side covers is formed between the inner ends of the side covers.

Abstract: A coupling which transfers torque from one shaft to another through a fitting portion of a key and a keyway. Seal members are provided in gaps which are formed between opposite surfaces of the key and keyway and which do not transfer torque, so as to prevent entry of water into the gaps without bearing pressure due to the torque.