Deployable and retractable cover
A cover system comprises at least one cover sheet having four edges and a plurality of flexible rafters. Each of the rafters is slidably connected to at least one of two opposite edges of the four edges, and at least one roller is provided on at least one of two other opposite edges of the four edges, wherein the roller is configured to rotate. The cover sheet is configured to wrap around the roller and be released from the roller, depending on a direction of rotation of the roller.
1. A cover system comprising:
at least one cover sheet having four edges;
a plurality of flexible rafters, each of the rafters being slidably connected to at least one of two opposite edges of the four edges; and
at least one roller provided on at least one of two other opposite edges of the four edges, wherein the at least one roller is configured to rotate, and each one of the at least one cover sheet is configured to wrap around the roller and be released from the roller, depending on a direction of rotation of the roller,
wherein the plurality of flexible rafters are configured to be wound with the at least one cover sheet into a compact structure.
2. The cover system of claim 1 , wherein the at least one cover sheet has a rectangular shape.
3. The cover system of claim 1 , wherein each of the rafters is slidably connected to at least one of two opposite longitudinal edges, and wherein the at least one roller is provided on at least one of two transverse edges.
4. The cover system of claim 1 , further comprising at least one support configured to support each of the plurality of rafters.
5. The cover system of claim 4 , wherein the at least one support is in a form of a pole that is configured to hold the plurality of flexible rafters above a surface of an open space.
6. The cover system of claim 4 , wherein the at least one support is a part of a structure that is covered by the cover system.
7. The cover system of claim 6 , wherein the structure is a greenhouse.
8. The cover system of claim 1 , wherein each of the plurality of rafters comprises:
a tube;
a cable threaded within the tube and extending out of the tube; and
one or two rails flexibly attached to the tube,
wherein each of the rails is configured to hold at least one of the at least one cover sheet and allow sliding of the at least one of the at least one cover sheet along the length of the rail.
9. The cover system of claim 8 , wherein the plurality of rafters further comprises one or two connectors, each connector being configured to connect each of the one or two rails to the tube.
10. The cover system of claim 9 , wherein the connector allows bending of the rail relative to the tube.
11. The cover system of claim 8 , wherein the one or two rails comprise a hollow along an entire length of the rail and a slot along an entire length of the rail, wherein the slot is positioned distally from the tube to which the rail is attached.
12. The cover system of claim 11 , wherein the rail has a round profile, and the slot has a substantially C-shaped profile.
13. The cover system of claim 11 , wherein a plurality of sliders is attached to at least one of two opposite edges of the four edges of the at least one cover sheet, wherein one of the plurality of sliders is configured to be threaded in the hollow of the rail, and slide along the rail, wherein the at least one cover sheet passes through the slot.
14. The cover system of claim 13 , wherein the plurality of sliders is attached to a longitudinal edge of a strip and wherein an opposite longitudinal side of the strip is attached to the at least one of two opposite edges of the four edges of the at least one cover sheet.
15. The cover system of claim 13 , wherein a friction between a surface of one of the plurality of sliders and an inner surface of the one or two rails, facing the hollow, allows smooth sliding of the one of the plurality of sliders along the rail.
16. The cover system of claim 13 , wherein a size of the one of the plurality of sliders is larger than a size of the slot, wherein the one of the plurality of sliders is confined within the hollow, and is configured to slide inside the hollow without being able to pass through the slot and disconnect from the rail.
17. The cover system of claim 13 , wherein the rail is configured to withstand a transverse force applied on the sliders that are within the hollow, and not bend in a manner that widens the slot and allows the sliders to be pulled out of the rail through the slot.
18. The cover system of claim 13 , wherein each of the one or two rails is configured to withstand a transverse force and prevent exit of the slider through the slot up to a certain threshold level, and when the level of the transverse force is higher than the threshold level, the rail is configured to become flexible and allow widening of the slot in a manner that allows exit of the slider through the slot.
19. The cover system of claim 1 , wherein the at least one cover sheet comprises a plurality of sub-cover sheets that are attached one to the other along a length of the at least one cover sheet.
20. The cover system of claim 19 , wherein the sub-cover sheets are different in their transparency.
21. The cover system of claim 19 , wherein a first roller is attached to one side of the at least one cover sheet, and a second roller is attached to an opposite side of the at least one cover sheet, wherein simultaneous rolling of the first roller and the second roller, in the same direction and velocity, causes changes of the positioning of the sub-cover sheets.