support rod is prevented from moving laterally or rotating in a presently preferred embodiment illustrated in fig6 the support rod 25 again having a preferably hexagonal shape is received by a hexagonally shaped opening 302 in a one piece mounting plate 300 as shown in fig7 five of the six faces of the hexagonally shaped opening 302 are defined by an interior surface of the mounting plate 300 the sixth face however is left open creating a gap 308 in the mounting plate 300 a bolt or other securing device may be placed through bore 310 in the regions 304 and 306 of the mounting plate thus forming a clamp as the bolt is tightened the regions 304 and 306 are forced toward one another clamping the support rod 25 in place within the opening 302 it will be appreciated that many other arrangements for suitably preventing the support rod 25 from moving laterally or axially rotating will occur to those skilled in the art and can be used in conjunction with the present invention the support structure 6 has been described in preferred embodiments to comprise separate parts such as the body piece 2 support rod 25 and mounting plate 30 it should be understood that in other embodiments the support structure 6 can be configured as a.