Roller for rewinding and tensioning a flexible element such as a sheet of material, shutter or similar, in particular for protections on machines

A roller for rewinding and tensioning a flexible element such as a sheet of material, a shutter or similar, in particular for protections on machines, said flexible element having greater length than width, and the roller including

• a tubular body, to the external surface of which one end of the flexible element is fixed;
• a pair of flanges which seal the ends of the tubular body;
• a shaft fitted coaxially to the tubular body and passing through the pair of flanges in such a way that the shaft can rotate freely, said tubular body and shaft being free to rotate relative to one another about a shared axis;
• at least one helical spring, driving element made of wire, housed within the tubular body, the ends of the spring driving element being attached to the shaft and to the tubular body so as to oppose rotation in the direction of unwinding of the flexible element from the roller;
• support and connecting parts for the ends of the spring driving element, connected respectively to the shaft and to the tubular body, said support and connecting parts having respective fixing surfaces, each having grooves for fixing the support and connecting parts respectively to the ends of the spring driving element, said support and connecting parts being securely fixed respectively to the shaft and the tubular body as it rotates about the axis,
• wherein at least one of the support and connecting parts is free to move longitudinally relative to the shaft, along the axis of rotation of the roller, by means of guides, the guides being positioned and shaped so as to allow the support and connecting part which moves along the axis of rotation of the roller to position itself along the shaft, in response to variations in the axial length of the spring driving element, said variations being caused by the unwinding and rewinding of the flexible element on the roller;
• means for transmitting rotation, operating between the tubular body and the support and connecting part which moves axially relative to the shaft;
• and
• the guides including at least one flat face, parallel with the axis inside an axial hole in one of the support and connecting parts which moves axially to the shaft, said flat face being attached to a matching face on the shaft, to prevent reciprocal rotation between the support and connecting parts and the shaft.

A roller for rewinding and tensioning a flexible element such as a sheet of material, a shutter or similar, in particular for protections on machines, said flexible element having greater length than width, and the roller including:

• a tubular body, to the external surface of which one end of the flexible element is fixed;
• a pair of flanges which seal the ends of the tubular body,
• a shaft fitted coaxially to the tubular body and passing through the pair of flanges in such a way that the shaft can rotate freely, said tubular body and shaft being free to rotate relative to one another about a shared axis;
• at least one helical spring driving element made of wire, housed within the tubular body, the ends of the spring driving element being attached to the shaft and to the tubular body so as to oppose rotation in the direction of unwinding of the flexible element from the roller;
• support and connecting parts for the ends of the spring driving element, connected respectively to the shaft and to the tubular body, said support and connecting parts having respective fixing surfaces, including grooves for fixing the support and connecting parts respectively to the ends of the spring driving element, said support and connecting parts being securely fixed respectively to the shaft and the tubular body as it rotates about the axis,
• wherein at least one of the support and connecting parts is free to move longitudinally relative to the shaft, along the axis of rotation of the roller, by means of guides, the guides being positioned and shaped so as to allow the support and connecting part which moves along the axis of rotation of the roller to position itself alone the shaft, in response to variations in the axial length of the spring driving element, said variations being caused by the unwinding and rewinding of the flexible element on the roller;
• means for transmitting rotation, operating between the tubular body and the support and connecting part which moves axially relative to the shaft;
• and
• the guides including at least one flat face, said face being made parallel with the axis inside an axial hole in one of the support and connecting parts which moves axially to the shaft, said flat face being attached to a matching face on the shaft in such a way that the hole and shaft form a prismatic coupling between the mobile support and connecting part and the shaft;
• said means for transmitting rotation including a connecting cover, in turn including one of the support and connecting parts which is free to rotate relative to the shaft, being rigidly fixed to one of the two flanges and connected by the spring driving element to the corresponding support and connecting part which moves axially to the shaft although being unable to rotate relative to the shaft.

An industrial machine tool having a mobile part movable along slideways between two extreme ends, and having a cover for covering at least the slideways, the cover comprising:

• a flexible element having greater length than width;
• a tubular element, supported by rotary bearings, and coaxially containing a shaft having first and second opposed ends, with the rotary bearings situated at the opposed ends of the shaft, the tubular element being supported by the rotary bearings;
• means for preventing any substantial axial sliding between the tubular element and the shaft;
• said cover being fixed at one end to the tubular element and at the other end to the mobile part of the machine;
• a first support, coupled to the shaft in such a way to rotate with the shaft, the first support being provided with a first seat;
• a second support, coupled to the tubular element in such a way to rotate with the tubular element, the second support being provided with a second seat;
• and
• at least one helical torsion spring, the spring having first and second ends, the ends of the spring being respectively fixed to first and second seats, and at least one of the first or second seats being longitudinally movable in respect to the shaft or with respect to the tubular element to which it is coupled, whereby the spring is free to vary its axial length according to the rotations of the tubular element.

A cover for covering at least a slideway along which a mobile part of an industrial machine moves back and forth between two extreme ends, said cover comprising:

• a flexible retractable covering part having a first and a second end, the covering part being positioned over the slideway and fixed at the first end to the mobile part of the machine;
• retracting means fixed to the second end of the covering part, for retracting the covering part such that whenever the mobile part of the machine is moving the covering part is retracted, the retracting means comprising:
• a support shaft having first and second opposed ends;
• two rotary bearings situated at the opposed ends of the shaft;
• an external tubular element, supported by the rotary bearings, and coaxially containing the shaft, the tubular element being rotatable with respect to the shaft by virtue of being supported by the rotary bearings;
• means for preventing any substantial axial sliding between the tubular element and the shaft;
• a first support, coupled to the shaft in such a way to rotate with the shaft, the first support being provided with a first seat;
• a second support, coupled to the tubular element in such a way to rotate with the tubular element, the second support being provided with a second seat;
• and
• at least one helical torsion spring, the spring having first and second ends, the ends of the spring being respectively fixed to first and second seats, and at least one of the first or second seats being longitudinally movable in respect to the shaft or to the tubular element to which it is coupled, whereby the spring is free to vary its axial length according to the rotations of the tubular element.