The present invention concerns a device (1) for preloading of a rewind mechanism (2) for a fabric (4) arranged on an elongated tube (3) or the like of a roller blind, a projector screen or the like. The rewind mechanism (2) is arranged to be essentially inserted into said tube (3) and includes a spring (10), that is tensioned when the fabric (4) is rolled out and relieved when the fabric (4) is rolled up onto the tube (3). The device (1) includes an outer mounting element (5), that is arranged to be attached to the tube (3), and an inner mounting element (6), that is arranged to be attached to an outer bracket (not shown), said mounting elements (5, 6) being rotatingly arranged in relation to each other about a longitudinal axis of said tube (3). A spring element (7) is arranged between said mounting elements (5, 6) and includes a sleeve (11), in which said spring (10) is arranged. The sleeve (11) has an inner diameter that is smaller than the outer diameter of the spring (10) in an untensioned condition, wherein said spring (10) is arranged inside the sleeve (11) by being inserted therein in a pretensioned condition.