{HEAD ~ said base} is supported by said bracket at four supporting portions equivalent to {TAIL ~ corners} of a square or a rectangle having two sides thereof extending along a front/rear direction and said load sensor are provided at, at least, two of said supporting portions; and further provided with: 
{ HEAD ~ said base } is supported by said bracket at four supporting portions equivalent to { TAIL ~ corners } of a square or a rectangle having two sides thereof extending along a front / rear direction and said load sensor are provided at , at least , two of said supporting portions ; and further provided with :
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH 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 OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH