| 摘要 |
Drive device for a roller with a screen which can be drawn up, which drive device comprises a wheel (1) which is connected in a rotationally driving manner to said roller and which is provided around the circumference with a running channel (6) which runs between an inner (1b) and an outer (1a) side of the wheel. This running channel grips around a running line (4a, 4b). The wheel is provided in the center with an attachment device (8) for rotatable attachment to a fixed casing (2), which casing contains a receiving part (12) for the attachment device (8), and an opening (14) for an incoming end and an outgoing end of the running line. A friction block (3) is, at a point (17) at a first end, attached to a fixed member, preferably in the lower part of the casing (2), the attachment facilitating at least partial rotation around said point. The friction block is shaped at a second end (16) to lie along a sector of a circle of the wheel, in or adjacent to said running channel (6), the ends (4a, 4b) of the running line running along either longitudinal side of the friction block. In the event of the roller and with it the wheel striving to rotate without a load on one of the ends of the running line, one of said ends of the running line is taken along in the rotation of the wheel and thereby presses said second end (16) of the friction block against the wheel (1), at which rotation is checked. |
