Transfer sleeve

A transfer sleeve, for being detachably set on a supporting unit and mounting a supporting arm, the supporting unit detachably penetrating through a plate and including a holder and a column disposed on the holder, the holder including a clamping element for abutting the plate, the supporting arm including a connecting hole, and the transfer sleeve comprising:

• a first tube body including a first surrounding wall, a first top wall, and a first accommodating space, wherein the first surrounding wall and the first top wall are connected to each other and jointly define the first accommodating space;
• a second tube body including a second surrounding wall, a second top wall, an opening, a second accommodating space, and a protruding edge extending from the second surrounding wall and toward the first top wall, protruding out from the second top wall, and being opposed to a large diameter section of the first tube body wherein the second surrounding wall and the second top wall are connected to each other and jointly define the second accommodating space, the second accommodating space is intercommunicated with the first accommodating space, the opening is formed on an edge of the second surrounding wall opposite to the second top wall, a groove is defined by the protruding edge, the second top wall, and the first tube body, and the groove matches with the supporting arm;
• when the transfer sleeve is set on the supporting unit via the opening, the column is accommodated in the first accommodating space, and the holder is accommodated in the second accommodating space, and when the supporting arm is set on the transfer sleeve, the first tube body penetrates into the connecting hole.