| 摘要 |
The coupling body (5) protruding from the bottom tube (2) has a recess in its top end for receiving the pin (3) extending between the inside walls of the top tube (1). The lower of the two recess side walls is angled so that contact with the pin generates a force acting in a diametrically opposed direction to the tilt direction of the top tube relative to the coupling body. The top tube defines a cavity (4) bridged by an essentially horizontal pin. The bottom tube is provided with a protruding coupling body which is received by the cavity in the top tube. A space is left between the coupling body and the cavity so that the top tube can be tilted relative to the body. |
