Trailer coupling

Claim 1

A VEHICLE INCLUDING A FRAME, MEANS FOR SUPPORTING SAID FRAME IN SPACED RELATION TO A SUPPORTING SURFACE INCLUDING WHEEL MEANS, MEANS MOUNTING SAID WHEEL MEANS ON SAID FRAME TO AFFORD PIVOTAL MOVEMENT OF SAID FRAME RELATIVE TO SAID WHEEL MEANS, A STRUT, AND MEANS MOUNTING SAID STRUT AT ONE END OF SAID FRAME IN SPACED RELATION TO SAID WHEEL MEANS FOR FRAME SUPPORTING ENGAGEMENT WITH THE SUPPORTING SURFACE, A HITCH BAR INCLUDING AT ONE END THEREOF A COUPLING ELEMENT ADAPTED FOR CONNECTION TO A COMPLEMENTARY COUPLING COMPONENT ON A TOWING VEHICLE, MEANS MOUNTING THE OTHER END OF SAID HITCH BAR ON SAID FRAME FOR VERTICAL MOVEMENT OF SAID ONE END OF SAID HITCH BAR RELATIVE TO SAID ONE END OF SAID FRAME WHEN SAID FRAME IS SUPPORTED ON SAID WHEEL MEANS AND ON SAID STRUT, SAID MEANS MOUNTING SAID OTHER END OF SAID HITCH BAR COMPRISING A PIVOT AFFORDING MOVEMENT OF SAID HITCH BAR THROUGH A VERTICAL ARC AND MEANS ON SAID FRAME FOR VARYING DISPLACEMENT BETWEEN SAID ONE END OF SAID HITCH BAR AND SAID ONE END OF SAID FRAME COMPRISING A LINKAGE INCLUDING A LINK PIVOTED AT ONE END TO SAID ONE END OF SAID FRAME, AND A LEVER PIVOTALLY MOUNTED ON SAID HITCH BAR, SAID LEVER INCLUDING ONE SHORT LEG PIVOTALLY CONNECTED TO THE OTHER END OF SAID LINK AND ONE FREE LONG LEG AFFORDING SUBSTANTIAL MECHANICAL ADVANTAGE OVER THE ACTION OF SAID LINK ON SAID SHORT LEG, AND A RELEASABLEK DETENT MECHANISM MOUNTED ON SAID HITCH BAR AND ON SAID LEVER FOR RELEASABLY PREVENTING SHIFTING OF SAID LEVER, WHEREBY SAID VERTICAL DISPLACEMENT MEANS IS OPERABLE TO POSITION SAID COUPLING ELEMENT FOR CONNECTION TO THE COUPLING COMPONENT WITHOUT EFFECTING THE DISPOSITION OF SAID FRAME ON SAID WHEEL MEANS AND SAID STRUT, AND WHEREBY WHEN SAID COUPLING ELEMENT IS CONNECTED TO THE COUPLING COMPONENT, SAID VERTICAL DISPLACEMENT MEANS IS OPERABLE TO ELEVATE SAID ONE END OF SAID FRAME RELATIVE TO SAID COUPLING ELEMENT AND TO THE SUPPORTING SURFACE SO AS TO RELIEVE THE SUPPORTING ENGAGEMENT OF SAID STRUT WITH THE SUPPORTING SURFACE.