A base 10 of the work platform is supported with {HEAD ~ a bracket} 9 at, {TAIL ~ at least, three supporting portions} 
at
A base 10 of the work platform is supported with { HEAD ~ a bracket } 9 at , { TAIL ~ at least , three supporting portions }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH REL OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL