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