Abstract: A transmission apparatus capable of mono-direction and dual-direction power transmission. It includes a mono-direction gear engageable with the output gear, a transversely slidable platform and an alternate dual-rotation actuating assembly. The alternate dual-rotation assembly includes a link having a first end, which is pivotally affixed to a third gear via a pin spaced apart from a center axis of the third gear, and a second end which is slidable on the vertical side wall of the platform; and a roller held in a roller seat which is slidably contacted by a compression spring. The link further includes first and second sides, the first side of the link having a teeth rack which is engageable with the output gear and the second side of the link is in contact with the roller.

Abstract: It is a detachable swivelling structure, which is particular a swivelling structure for mounting a swivelling Christmas tree. The swivelling structure comprises a round base, four supporting legs to be assembled at a perpendicular angle one another or disassembled, a lid, and a turning base. After the four supporting legs being assembled together, they are mounted under the round base so as to have a larger base to hold the swivelling tree in a stable manner.