Title: Link chain for retractable screens

The invention is part of the devices that allow the guiding of a fabric like a retractable screen, mode.

State of the prior art

From the sta te of the art there are known devices that allow the guiding of fabrics like retractable screens comprising chains or rigid elements articulated as the caterpillar chains described for example in the patent publications EP1903I75, EP190S944, EP2312113, A problem m the rigid elements or chain for retractable screens from state of the art is that these have surfaces with cavities which allow the accumulation of dirt.

In addition, another problem that these chains sometimes have is the manner in whi the binding is achieved among the different links in the chain, that offers only a delicate security in ensuring that the links do not loose among themselves during the operation, of the retractable scree motion system.

Explanation, of the invention

Retractable screens include for example a pleated antbmosquito net fabric. These screens axe devices characterized by extending a fabric closing an opening, and then being able to retract it again, for returning to the initial state. The net fabric is arranged between two vertical rigid elements or posts, joined together by two flexible or articulated rigid elements or chains that slide to the inside of the vertical rigid elements, while its enter span, remains horizontal between the vertical rigid elements.

A main objective of the present invention, is to propose a link chain which exceeds the limitations of the previous ones, introducing a. new principle of assembly, a minimisation of cavities where dirt can. accumulate, a novel anti -rotation and/or anti-disassembly security system.. Accordingly it is alse a further object of the present invention to propose an improved link T/NL2012/050930

chain and ckam link for use in an articulated caterpillar screen guiding member. In a more general sense it is thus an object of the invention to overcome or ameliorate a.t least one of the disadvantages of the prior art, or to provide alternative structures, which are less cumbersome in assembly and operation and which moreover can be made relatively inexpensively. Alternatively it is an object of the invention to at least offer a useful choice.

To this end the invention provides for a. link and an articulated chain, assembled from such links, as defined in the appended claims.

The links in. the chain preferably have a structure formed, by two side wails parallel each other and joined by a web extending transverse to them which has a hook at a. front with, a hook opening and has attached to its rear a cylindrical shaft. Whe the links have been joined together to form a chain, two adjacent links join each other in. an articulated manner with the cylindrical shaft of one of them being introduced through the hook opening of the adjacent link.

in. addition the links of the present invention preferably has a geometric shape that permits only rotation, of the chain to one side and limiting the angle of rotation of the chai to the permitted side. The links incorporate protrusions at the top, both the front and the rear in. such a manner that w!ren the chain is mounted the fro t top protrusion of a link is placed into contact with, the rear top protrusion of an. adjacent link in such a manner that they allow the rotation only to one side.

The limitation of the angle of rotation is advantageously achieved due to a vertical step that is inside of the links and which has curved shape. When this vertical step from a link comes into contact with a vertical side of an adjacent link it allows the rotation of both of them, hut only to an extent in. which the curvature of the vertical step changes and the inclined vertical side of a link can not continue sliding by said step.

In addition each of the links also preferably has on its top a front inclined surfa.ee and a rear inclined surface that when the links are 0

3 mows ted, allow the separation of the top part so that the rear part of a. link is introduced, inside of the front of a second link.

Throughout the description and claims the word "comprises" and its variants are not intended to exclude other technical features, additives, components or steps. For those skills in the art, other objects, advantages and features of the invention will be understood partly of the description and partly of the practice of the invention. The following examples and drawings are provided by manner of illustration, and are not intended to be limiting of the present invention. In addition, the present invention covers all possible combinations of particular and preferred em bodiments here indicated.

Brief descriptio of the drawings

FIG. I shows a perspective view of a link chain object of the invention in which the limitation of the rotation is appreciated (in the right area of figure it ca be seen, how the chain, can only rotate upwardly) and it can be seen, how the links are placed in the chain (in the left area of the figure it can. be seen, a link placed, perpendicularly to the chain for its placement in. this chain).

FIG. 2 shows a vie in. perspective of a link in the chain.

FIG, 3 shows a. section of a link in the chain for its plane of symmetry,

FIG. 4 shows a profile view of a. link in the chain,

FIG. S shows a perspective view of a link in the chain, of the invention in perpendicular position, to the chain for its assembly.

References

1: l nk; 2: First protrusion; 3: Cylindrical shaft; 4: Hook; 5: Vertical step; 6: Second, protrusion; 7: Inclined, vertical sides; 8: Lateral side wails; 9: Transverse web; 10: Front inclined surface; 1.1; Rear inclined surface; 12: Central cut-out.

Detailed exposition of embodiments

The link chain for retractable screens of the invention consists of links (1) that are rigid elements, and these links are articulated to each other. Each link is composed by two lateral side walls (8) parallel to each other and joined by a transverse web (9) perpendicular to them. This transverse web (9) has at its front end a hook. (4) with a cylindrical shape and a hook opening facing in a direction perpendicular to the transverse web (9). Optionally a central cut-out (12) may additionally he provided, in amidst of the hook (4). in the area, of the rear end of the transverse weh (9) there is a cylindrical shaft (3) placed in parallel with the transverse web (9) and joined to the opposite lateral side wails (8). Optionally the cylindrical shaft (3) may additionally be fixed in its middle to the transverse web (9). When mounting the chain,, the links axe connected to each other by placing the hook. (4) of a second link around the cylindrical shaft (3) of a first link that is adjacent to it in forming the chain. In this manner the links are joined in an articulated manner because this type of join allows the rotation of the links one with regarding to the other. If the cylindrical shaft (3) is additionally fixed to the transverse web (9) in its middle, then the optional central cut-out (12) will accommodate the additional fixation of the

cylindrical shaft (3) to the transverse web (9),

The lateral walls (8) comprise in the side that is inward of the links (1) a vertical step (5) so that the rear area, which is the area, in which is the cylindrical shaft (3), it is narrower tha the front area, which is the a.rea in which it is the hook (4). This allows that when the chain, is mounted, the rear area of a first link remains inside of a second link adjacent to it, remaining the front area of the second link outside of the rear area of the first link. The vertical step (5) is curve -shaped, to ensure that the rotation of a link to its adjacent Jink occurs only to one side. Thus the vertical step (5) is curve-shaped in the top part and is straight at the bottom so that the link adjacent to it can rotate in respect of the top, and rn relation, to the bottom is, at most, perpendicular. The vertical step (5) has a different shape rn the in e surface of the lateral walls (8) than on the outer face to properly limit the rotation to only one side.

Links (1) also comprise other limitative surfaces of rotation of the links. Specifically, they comprise a. first protrusion (2) which is located at the rear top of each of the lateral side walls (8). Each lateral side wail (8) has two inclined vertical sides (7) and. has its bottom end curve-shaped to allow the rotation, in relation to the adjacent steps and. has straight horizontal sides. The inclined vertical sides (7) limit the rotation of the links when coming into contact with the vertical step (5) of the adjacent link. Thus, when the inclined vertical side (7) of a second link slides by the vertical step (5) because of the movement of rotation of the chain, there is a moment in which the vertical step (5) of the first link, due to the above described geometry, prevents that the rotation of the second continues.

The first protrusion (2) is vertical and is located in the outer face of the lateral side walls (8), in. the rear part. The links also comprise a second, protrusion (6), also vertical, and located, in the inner side of the front top of each of the lateral side walls (8). When the chain has been mounted, the rotation of the links is limited since when, it is attempted to turn the chain to a side in winc it is limited, the first protrusio (2) in a first link comes into contact with tbe second protrusion (6) of the second, link thus preventing the further rotation of the chain in this direction.

The first protrusion (2) and the second, protrusion (8) come into contact during the assembly of the chain so that the top of the links (1) separates to allow the assembly and subsequently restores to its initial.

position which is the final position, in the chain. The assembly of the link chain will be carried out placing a second link in perpendicular orientation with respect to a first link so that the hook (4) is engaged under pressure around the cylindrical shaft (3) allowing an articulated joint. Then the second link is rotated about a quarter until the transverse web of the second link is aligned with the height of the

transverse web of the first link.

The lateral walls (8) have a front inclined surface (10) which is located at the upper front part of the link (1) where the second protrusion (8) is located. They also have a rear inclined surface (11) which is located in. the upper hack part of the link where it is part of the first protrusion (2). When the chain is mounted, when turning the second link with respect to the first link to leave both links to the same height, the front inclined surface (10) of the second link comes into contact with the rear inclined surface (11) of the first link in such a manner that the front top part of the second link is separated. In this manner the rear part of the first link is introduced into the inside of the front part of the second link. Hence the inclined surfaces (10, 11), acting as ramps, open elastically the lateral walls of the link at the top.

Once the chain is mounted, the first protrusion. (2) and the second protrusion (6) limit the rotation of the chain in such a manner that they allow this rotation only to one side since in attempting to rotate the chain to the opposite side the first protrusion (2) and the second protrusion (8) come into contact. The inclined vertical sides (?) together with the vertical step (5) limit the angle of rotation of the chain to the side in which the rotation is permitted, The inclined surfaces (10, 11) allow assembly of the chain since the inclined surfaces of two links adjacent to each other come into contact separating the front top part of one of the links so as the rear top part of the other one is left inside.

Th s a link chain for retractable screens for easy assembly is described, which has a limited the angle of the rotation due to a first protrusion (2), located on the rear top of the links (1) and a second

protrusion (6), located on the front top of the links (1) such that when bot h protrusions come into contact they prevent the link chain to rotate farther in that direction. Also the links (1) each incorporate a vertical step (5) on the inner side by which a inclined, vertical side (7) of an. adjacent link slides in. such, a manner that the chain can only be rotated over a predetermined angle defined by the contact of the inclined vertical side (7) of a. link and the vertical step (5) of the adjacent link. Links (I) inclnde a front inclined surface (10) and a rear inclined surface (II), which are flexible in order to facilitate the assembly of the chain- As can he clearly seen in Figures 1 and 6, the left hand chain link is shown in the position, in which it is being connected, to the already partly assembled, chain. In. this position the slot-like opening of the hook (4) can be ushed over the cylindrical shaft (3) ef a. chain link previously connected to the chain. The inclined surfaces (10) of the second protrusions (6) of the jnst connected link has not yet engaged the inclined surfaces (11) of the fi st protrusions (2) of the previously connected link, Once the shaft (3) has been, snap-fitted completely into the hook (4) the last connected link is pivoted upwardly to align its transverse web (9) with those of the rest of the chain links. During tins motion the inclined surfaces (10. 11.) upon contacting one another cause the upper front portions of the side walls (8) of the freshly attached link to ilex outwardly and the upper rear portions of the previously attached link to flex inwardly, so that the first protrusions (2) pass the second protrusions (6), Rotating back to the mounting position will thereafter he prevented, by the first and second protrusions (2. 8) abutting against each other. Rotating to the opposite side will remain possible ever the angle allowed, before the inclined, vertical edge (7) of the link engages the vertical step (5) of the adjoining link. This new principle of assembly successfully ensures that the links do not accidentally get loose from one a other during the normal operation and motion of the retractable screen guiding system, thereby providing an anti-disassembly security system.

It is thus believed that the operation and. construction of the present invention will be apparent from the foregoing description and drawings appended thereto. It will he clear to the skilled person that the invention is not limited to any embodiment herein described and that modifications are possible whrch should be considered within the scope of the appended claims.. Also kinematic inversions are considered inherently disclosed and to be within the scope of the invention. In the claims, any reference signs shall not be construed as limiting the claim. The term

'comprising' and 'including when used m this description or the appended claims should not be construed in an exclusive or exhaustive sense hut rather in an inclusive sense. Thus the expression 'comprising ⁵ as used herein does not exclude the presence of other elements or steps in addition to those listed in any claim. Furthermore, the words ^f a ^! and 'an ³ shall not be construed as limited to 'only one', but instead are used to mean ^s at least one', and do not exclude a. plurality. Features that are not specificall or explicitly described or claimed m ay be additionall included in the structure of the invention within its scope. Expressions such as: "means for ..." should be read as: "component configured for or ''member constructed to ..." and should he construed to include equivalents for the structures disclosed. The use of expressions like; "critical", "preferred", "especially preferred" etc. is not intended to limit the invention. Additions, deletions, and modifications within the purview of the skilled person may generally he made without departing from the spirit and. scope of the invention, as is determined by the claims.