Spherical couplings for vehicle towing or kindred purposes

#The invention relates to a ball-joint coupling comprising a male coupling member provided with a ball and a female coupling member having a socket to receive the ball, such coupling finding particular application in the hitching of trailers or caravans to motor or other vehicles.

#Prior art couplings of this kind have various disadvantages. They are noisy because of their clearances and the resulting jerks during towing or braking. In addition, they permit the trailer or caravan too much freedom, in that they do not prevent it from pitching, rolling or swaying.

#Various improvements have been proposed to obviate these disadvantages, but the previously proposed means are usually expensive and provide only partial solutions to the problem. More particularly, it has been proposed to cover the ball with a rubber layer, but the prior art arrangement proposed to this end is bulky and increases the difficulty of coupling and uncoupling the female coupling member or hitch co-operating with the ball.

#FIGS. 1 to 3 show a coupling embodying the invention, FIG. 1 being a vertical section along the hitch bar and FIGS. 2 and 3 being respective cross-sections along lines II--II and III--III of FIG. 1;

#FIG. 4 is a perspective view of the ball of the coupling of FIGS. 1 to 3 with the associated cap mounted thereon;

#FIG. 5 is a horizontal section through another embodiment;

#The drawings illustrate, by way of example, a ball joint coupling for hitching a motor vehicle and a trailer or caravan together.

#The coupling comprises a male coupling member having a ball 1, provided e.g. in conventional manner at the end of a tail 2 borne at the rear of the vehicle, inter alia in a vertical direction. The ball 1 is covered with at least one layer of rubber or other elastomer and is coupled to a female coupling member or hitch bar of the trailer, so that relative motion of the male and female coupling members is accompanied by deformation and shearing of the rubber.

#To this end, a rubber layer 3 is stuck to the useful spherical part of ball 1 and also to the inner surface cap 23, which may be made of metal and is mounted so as to be driven, during its relative motion, by the female coupling member or hitch bar 5.