views of the coupler 20 being coupled to a head 16 in accordance with the present invention in fig4 a a neck 21 and ball 60 of the jack assembly are pushed into the socket 62 of the coupler with reference to fig4 b once inserted the ball 60 is press fit into the socket 62 while neck retainers 52 extending from the body 50 prevent motion in the lateral direction as indicated by arrows 76 in addition with reference to the top view of the ball 60 and neck 21 assembly of fig4 c the neck can be provided with a flange 61 having flat edge features 63 as shown the flat edges 63 of the flange 61 are configured such that when the ball is mounted into the socket as shown in fig4 b the flat edges 63 interface with the inner surfaces of the neck retainers 52 thereby preventing horizontal pivot of the head 16 assembly about the neck 21 as indicated by arrow 77 in this manner greater control over the positioning of the head can be realized during mounting returning to fig4 a when inward pressure as shown by arrows 78 is applied to the handles 64 of the coupler 20 the body 50 of the coupler flexes and the arms 68 move in an outward direction as indicated by arrows.