摘要 |
A driving device comprising a shaftless spiral (10) rotatable around its longitudinal axis and enclosed by limiting means (20, 59). The limiting means has a first end region (23) and a second end region (24) corresponding to each end of the limiting means. The shaftless spiral encloses a sliding body (30) which is provided with an element (31) projecting from the sliding body, which passes between two adjoining spiral turns (16a,16b) of the spiral and has a part (33a,33b) located radially outside the spiral turns in a slot oriented substantially in the axial direction of the limiting means. A driving means (40) rotates the spiral, which moves the sliding body (30) and consequently the projecting element (31) in the longitudinal direction of the spiral. |