The support plate may be provided with a rib frame structure including a plurality of ribs in a horizontal direction corresponding to {HEAD ~ a direction} of {TAIL ~ 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 ribs in a horizontal direction corresponding to { HEAD ~ a direction } of { TAIL ~ 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 OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL 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