The support plate may be provided with {TAIL ~ a rib frame structure} including a plurality of ribs in a horizontal direction corresponding to a direction of the first tilt shaft and a plurality of ribs in a vertical direction corresponding to {HEAD ~ a direction} of the second tilt shaft 
The support plate may be provided with { TAIL ~ a rib frame structure } including a plurality of ribs in a horizontal direction corresponding to a direction of the first tilt shaft and a plurality of ribs in a vertical direction corresponding to { HEAD ~ a direction } of the second tilt shaft
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL 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 OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH