Dual-purpose chair

A dual-purpose chair comprising:

• a seat structure formed of a seat and a backrest and a backrest support frame, said seat having a pair of side rods affixed on opposite sides of said seat, said seat having a pair of support rods on an underside thereof, said backrest having a pair of side rods affixed on opposite sides thereof, each of said pair of side rods of said backrest having a support portion at a bottom end thereof, said backrest support frame having a pair of arms at opposite sides thereof, said pair of arms of said backrest support frame being connected together by a crown portion, said pair of arms of said backrest support frame being respectively pivotally connected at a free end thereof to said pair of side rods of said backrest, said pair of arms of said backrest support frame being respectively pivotally connected at a midsegment thereof with said pair of side rods of said seat, said crown portion being positioned under one end of said seat;
• and
• a base structure having an upright rod and a plurality of caster seat arms extending radially outwardly from a bottom end of said upright rod, said base structure having a support plate mounted on a top end of said upright rod, said support plate having a plurality of fastening holes formed therein, said base structure being detachably fastened to said seat structure by a plurality of fastening bolts, said pair of support rods of said seat being fastened to said support plate of said base structure by said plurality of fastening bolts, said plurality of fastening bolts being respectively received in said plurality of fastening holes.