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