Abstract: Power unit that can be telescopically lengthened or shortened and performs linear movement, and includes cylindrical parts moving telescopically within each other. The cylindrical parts are equipped with at least external or internal threads to form a power unit that can be lengthened or shortened when the parts are being rotated in relation to each other. At least one cylindrical part is locked to be non-rotating or locked to rotate differently than a last cylindrical part to which a rotating producing movement to the power unit is arranged. The cylindrical parts are made of plastic and the inner diameter of the part having the smallest diameter is over 25% of the useful height produced by the smallest cylindrical part.

Abstract: Power unit that can be telescopically lengthened/shortened and performs linear movement which power unit comprises cylindrical parts (1-3) moving telescopically within each other in which case the mentioned parts are equipped with at least external or internal threads in such a way that the mentioned parts form a power unit that can be lengthened/shortened when the parts are being rotated in relation to each other and that at least one part (3) of the mentioned parts (1-3) is locked to be non-rotating or locked to rotate in a different way than the part (1) of the mentioned parts (1-3) to which part a rotating producing movement to the power unit is arranged. In order to reduce the construction weight of the power unit the mentioned parts (1-3) are made of plastic and of the mentioned parts the inner diameter (d) of the part (3) having the smallest diameter is over 25% of the useful height (H) produced by the mentioned smallest part.

Abstract: Lifting/lowering apparatus comprises a lower frame (1), a horizontal upper frame (7) supported by which a plane is adjusted and comprises a lifting mechanism adjusted between the mentioned lower frame and upper frame with the help of which lifting mechanism the upper frame (7) can be lifted and lowered in relation to the lower frame (1) and that the lifting mechanism comprises adjacent pillars (2, 3, 4), each pillar is formed of cylinder parts (2-4) that can be moved telescopically in relation to each other which cylinder parts are attached to each other by threads such that the rotation of the parts (2-4) in relation to each other changes the height of the pillars. In order to reduce the construction weight the cylinder parts (2-4) are made of plastic and in order to improve the receiving of the sideway loadings the inner diameter of the cylinder part (4) having the smallest diameter is over 200 mm.