Patent ID: 6505668
Filing Date: 2003-01-14
Classification: E06B

Abstract:
Roller curtain with back rolling force, comprising:two end members for fixing the roller curtain on wall faces, the end members being spaced apart from each other; a locating mechanism connected with a first of the two end members; a reel which is a tube body positioned between the two end members with a first end fitted on the locating mechanism, whereby the reel is drivingly rotatable by the locating mechanism; a fluid pressure cylinder having a cylinder body and a piston stem axially passing through the cylinder body, such that, when not subject to external force, a front end of the piston stem is outwardly projecting, the piston stem being extensible from the cylinder body without rotation, the pressure cylinder being fitted in the reel with the piston stem directed inwardly, a rear end of the cylinder body being connected with a second of the two end members, a second end of the reel being rotatably fitted with the cylinder body; a curtain connected with the reel and wound or unwound by the reel; and a linking device disposed between the reel and the piston stem of the pressure cylinder, the linking device connecting rotational movement of the reel into linear movement of the piston stem in parallel to an axis of the reel, whereby when the reel rotates to unwind the curtain, the linking device retracts the piston stem into the cylinder body to reserve a pressure source in the pressure cylinder, while when the reel rotates in a reverse direction to wind the curtain, the linking device makes the piston stem extend out from the cylinder body and the pressure of the pressure cylinder is relieved to enhance the displacement of the piston and to provide back rotating force for the reel, wherein the linking device further includes a spiral flute section and a spiral tooth section, the spiral flute section having a plurality of spiral flutes and disposed on an inner circumference of the reel and rotatable along therewith, the spiral tooth section having a plurality of spiral teeth and being disposed at a front end of the piston stem, the spiral tooth section being engaged with the spiral flute section.