and has a stop member 67 a such as an annular ring as in fig5 or any other suitable appurtenance or attachment accomplishing the desired function at or near inner end 69 a an annular groove 69 c is formed in shaft 69 near outer end 69 b as best seen in fig2 and 3 pivot pin 67 may be inserted through pivot pin bore 51 such that outer end 69 b of shaft 69 projects beyond outer end 44 b of second hitch section 44 the projecting outer end 69 b of shaft 69 may then be disposed within semi cylindrical cavity 62 a of first pivot block section 62 whereupon second pivot block section 64 may be engaged with and fastened to first pivot block section 62 as previously described as a result of this assembly the axis of pivot pin 67 will coincide with pivot axis xp in the illustrated embodiment fastener holes 66 of first and second pivot block sections 62 and 64 are configured such that fasteners 68 when inserted through fastener holes 66 will at least partly intercept annular groove 69 c of shaft 69 when said annular groove 69 c is longitudinally aligned with fastener holes 66 by means of this arrangement fasteners 68 will retain pivot pin 67 longitudinally within pivot block passage 65 while still allowing pivot pin 67 to rotate about pivot axis xp within pivot block passage 65 pivot pin 67 is longitudinally retained within pivot pin.