Energy recovery winch to operate curtains and roller blinds

Claim 2

An energy recovering winch for roller blinds, characterized in that it is substantially formed by a manual control shaft (1) to whose outer end (3) there is applied the known manual operation device common to all the curtain winding up mechanisms, and on whose opposite end (5) disposed inside the control housing (7) there is keyed a bevel gear (9) in direct drive engagement with another bevel gear (11) orthogonal to it and coaxial to the winding up shaft (13); at the inner end (5) of said control shaft (1) there being mounted, in register with the first bevel gear (9), a support bushing (15) on which an irreversibility device is mounted which allows the gear (9) to move in one or the other direction of rotation, only when the movement comes from said control shaft (1), and preventing the movement to said control shaft (1) when the rotation drive is imparted to the gear (9) coaxial to the said control shatf; on the second bevel gear (11), perpendicular to the first bevel gear, there being keyed a central shaft (13) coaxial to the winding up shaft (17), rigidly connected to this latter and extending inside it, on which shaft there is wound a double helical spring (27) connected, on one hand, to a fixed point of the control housing (7) and, on the other hand, to a fixed point (29) of the curtain winding up shaft (17); the lowering movement of the curtain and the resulting rotation movement of the roller (17) on which the curtain is wound, torsionally loading said spring (27) which will store said energy and return it to the user during the lifting of the curtain, thereby facilitating said lifting of the curtain itself.

Claim 3

An energy recovering winch for roller blinds according to Claim 1, characterized in that the irreversibility device provided in the control box (7) of the winch is substantially formed by a helical spring (33) anchored with one of its ends on a keyed bushing (15) rigidly connected at (5) to the control shaft (1); said bushing (15) for hooking the helical spring (33) supporting laterally a circular sector (35) having a rotational clearance with respect to the cavity of the hub (37) of the first bevel gear (9), in which cavity said bushing (15) is housed; the hub (37) of said first bevel gear (9), the hooking bushing (15) for hooking the helical spring (33), and the spring (33) itself being lodged in a special block (41), for example an antifriction block, provided at the end of the housing (7) of the control shaft (1); the irreversibility mechanism being created in virtue of the fact that, when the drive of rotation, in one or the other direction, is directly given by the shaft (1), the rotational clearance provided between said shaft (1) and the hub (37) of the bevel gear (9) gives rise to a narrowing of said helical spring (33), because this latter is pulled by the shaft (1) with respect to the cavity of the hub (37) of the bevel gear (9), thus allowing the relative rotational movement of the spring (33) with respect to the seating (39) of the hub of the gear (9) and the antifriction lodging block (41); while, instead, when the drive of rotation is given directly to the bevel gear (9), this latter rotates, in one or the other direction relative to the bushing (15) to which the helical spring (33) is fastened, in a direction opposite to the "pulling" direction, thereby widening the spring (33) itself which exerts a pressure against the cylindrical wall of the seating (39) of the block (41), in which it is housed, thus locking said rotational movement in one and the other direction.

Claim 4

An energy recovering winch for roller blinds according to the preceding Claims, characterized in that the braking helical spring (33) of the irreversibility device has an opening between the ends, which is equal to a center angle of 30°-3 5 °, and particularly 32°-33°; the circular sector (35) of the bushing (15) engaging said helical spring (33), having an amplitude of about 45°, still measured as a center angle; the missing zone of the sector hub (37) of the first bevel gear (9) forming a center angle of about 120°.