| 摘要 |
A linkage device connectable between adjacent ends of a tubular support member and payload member is adapted to rotate the payload member through approximately 180 DEG about the end of the support member between inoperative and operative positions by movement of an actuating rod longitudinally within the tubular member. The linkage device comprises first and second frames secured to adjacent ends of the members and four bars pivotally connected at opposite ends to corners of the frames, the first pair of bars extending within the frames and the second pair extending outside the frames. The actuating rod is connected to the first pair of bars and rotates them about their pivotal connection to the first frame when the rod is moved longitudinally within the tubular member. Both pairs of bars cause the payload member to rotate about the end of the support member through 180 DEG and into an operative position in longitudinal alignment with the support member.
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