Structure of motorcycle stand

The motorcyle stand, comprising a substantially H-shaped tubular frame defining therein two cylindrical side chambers vertically disposed at two opposite sides with a cylindrical cross chamber transversely disposed therebetween, said cross chamber having set therein a transmission gear set to drive two driving bevel gears to respectively drive two extendible supports to respectively extend out of said two cylindrical side chambers for supporting a motorcycle in place or receive inside said two cylindrical side chambers permitting said motorcycle to be driven to move, wherein said two extendible supports are each comprised of:

• a socket having an annular top flange projecting outwards at the top for mounting a ball bearing, and two opposite projecting strips respectively projecting inwards at the bottom;
• a transmission tube fastened to the inner top of either one of said two cylindrical side chambers via a ball bearing, having a collar at the middle thereof and carried on the top edge of the ball bearing mounted on said annular top flange, and an inner thread on the inner wall surface thereof, said collar having a notch made thereon;
• a ring-shaped bevel driven gear sleeved on said transmission tube and engaged with either one of said two driving bevel gears, having a vertical plate at the bottom thereof and fastened in said notch on said collar for driving said transmission tube to rotate;
• a driven screw bolt having a butterfly boring bore through the central axis thereof, an extended head, and an elongated outer thread portion extending downward from said extended head at the center;
• a T-shaped driving rod, having two unitary, columnar ribs at two opposite sides respectively engaged in said butterfly boring bore and driven by said transmission tube to carry said driven screw bolt to rotate;
• a tube-shaped movable coupling having a raised outer thread portion on the smooth outer wall surface thereof at an upper end and engaged with the inner thread of said transmission tube, an annular projection projecting in the bore thereof to support the extended head of said driven screw bolt permitting said driven screw bolt to be driven by said T-shaped driving rod to rotate inside said tube-shaped movable coupling, two elongated inner grooves on the inner surface wall thereof at two opposite locations, and two elongated outer grooves on the outer wall surface thereof at two opposite locations and respectively engaged with the two opposite projecting strips of said socket;
• a movable tube having two opposite projecting strips on the outer wall surface thereof at one end and respectively engaged in the two elongated inner grooves of said tube-shaped movable coupling, and an inner thread over the inner wall surface thereof and engaged with the outer thread portion of said driven screw bolt;
• and
• a shoe made of resilient material in circular shape, having a stub rod at the top center thereof and fastened in said movable tube at the bottom.