{TAIL ~ Slider members} are provided having a clamp member operatively associated therewith for movably securing the restraining bar to the supporting rails and include a device for retaining {HEAD ~ the clamp} in an operatively associated position relative thereto 
{ TAIL ~ Slider members } are provided having a clamp member operatively associated therewith for movably securing the restraining bar to the supporting rails and include a device for retaining { HEAD ~ the clamp } in an operatively associated position relative thereto
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH