| 摘要 |
PCT No. PCT/SE85/00469 Sec. 371 Date Jul. 23, 1986 Sec. 102(e) Date Jul. 23, 1986 PCT Filed Nov. 19, 1985 PCT Pub. No. WO86/03181 PCT Pub. Date Jun. 5, 1986.A power unit of the type varying its length comprises three members movable in relation to each other. The power unit is used for transferring load from a first load carrier to a second one. In order to make this transfer possible in a satisfying manner, the power unit has to be constructed so that it can be extended to at least two times its length in the contracted state. For this reason it is a necessity that transmissions comprising wheels (13) and a loop (15) laid around these are so arranged, that when the third member (3) is displaced with respect to the first member (1) fixed in the room, at the same time the second member (2) is displaced in the same direction and the same distance with respect to the third member (3). In order to solve this problem in an appropriate manner the invention proposes to design the first member (1) with at least partly the character of a housing for the power unit, with an elongated shape in cross section. The power device (6, 7, 8, 9, 10, 11 ) for displacement of the members (1, 2, 3) is disposed generally in the central region (22) of this housing. The transmissions are two in number and they are generally symmetrical in a mirror image relation to each other with respect to a plane comprising the longitudinal axis of the power device and being perpendicular to the greater dimension of the cross sectional shape of the housing (S-S plane). |
