WO2003086048A2

WO2003086048A2 - Greenhouses, films for covering greenhouses and methods for stretching or tightening films on greenhouses

Info

Publication number: WO2003086048A2
Application number: PCT/FR2003/001176
Authority: WO
Inventors: Patrick Fortier
Original assignee: Patrick Fortier
Priority date: 2002-04-15
Filing date: 2003-04-14
Publication date: 2003-10-23
Also published as: AU2003246828A8; WO2003086048A3; FR2838287A1; AU2003246828A1; FR2838287B1; EP1551216A2

Abstract

The invention relates to a greenhouse (1) comprising roof bows (2) which are covered by at least one film (3), said film (3), or the main film if a plurality of films covers the roof bows, comprising at least one sleeve (4) in which a rod (5) is guided and thus fixed to the film (3). The sleeve (4) is longitudinally arranged over the entire length of the greenhouse (1). The invention also relates to a film for a greenhouse, comprising at least one sleeve (4) which extends over the length of the film (3) at a distance from the lateral edges thereof, and to a method for stretching a film over a greenhouse.

Description

Greenhouses, greenhouse cover films, and method for tensioning or retightening greenhouse films

The present invention relates to greenhouses, greenhouse cover films and a method for stretching or retightening greenhouse films.

Currently the majority of greenhouses include hoops on which plastic films are stretched.

FR-A-2 188 937 describes greenhouses which, when they are large, include longitudinal sheaths containing a stiffener connected to the ground by cables. Small in size, they can be entirely made up of a double-walled envelope, a ballast being installed between the two walls and finding itself by gravity at ground level.

US-A-3,741,631 describes a radiation screen consisting of a double-walled envelope forming multiple strands alternating opaque and transparent areas.

Greenhouses, in particular industrial greenhouses, can be elongated tunnels whose structure consists of metal arches generally semi circular or in basket handle generally of rounded shape or Gothic shape of a few meters wide on the ground, for example 5 to 10 meters , spaced a few meters apart, for example 1, 5 to 3 meters and whose ends are fixed laterally in the ground by various means, they can also be structures with multiple tunnels (coupled tunnels) or even structures with multiple chapels, where the arches always formed by arches rest on posts connected to each other by a gutter called a gutter collecting and discharging rainwater collected by the arches.

It is essential that the films are permanently perfectly stretched over the structures. Indeed, if this is not the case, they can offer a hold in the wind and start to toss, which causes their rapid wear by friction at the points of contact with the structure and their destruction. However, generally the films used for greenhouse coverings have been stabilized for a period of several years.

To achieve this good tension, on tunnels and multiple tunnels, when they are covered with a single film lengthwise (the width of the film corresponding to the development of the arch), provision can be made to press the film onto the structure by stretching cables over the film in the space left between each arch. The ventilation is then done by raising the edges of the film which remain caught between the cables and the arches. However, wear then occurs at the locations of friction of the film with the tension cables and in fact, this system is generally used only for films with a short lifespan (2 seasons for example).

It is also possible to provide for the fixing of the edges of the film by continuous lines of clipping produced industrially for this purpose. But once the edges of the film are fixed to the clips and to the structure, the film must still be stretched and often have to be stretched during the hot season when the film reaches its maximum expansion. The tension of the film is generally carried out by approach, hoop after hoop and it is therefore a long operation whose result is often imperfect, and during which the film has often been weakened. The installation of the films can be done by burying the lateral ends of the film in trenches provided along the alignment of the fixing of the poles to the ground for tunnels.

For this type of installation, the tunnel is covered by several overlapping widths, each covering at least the interval between two arches. But then, as the ventilation is ensured by the spacing of the widths overlapping each other over approximately 50 cm, the effectiveness is very limited.

On greenhouses with multiple chapels the films are most often fixed on continuous clipping lines integral with the gutters for one side. The other edge of the film is generally fixed to a movable line also equipped with clips closing the continuous opening which equips each chapel. The film is thus fixed to the structure, the opening in the open position, then in order to achieve tension, the opening is closed and a blade is screwed through the film onto the hinge bar of the opening. But this practice is long and it limits the width of the opening to a reasonable distance from the gutter in order to be able to screw this blade on the hinge bar. But if the tension thus obtained proves to be insufficient, it is practically impossible to retighten the film.

Another type of installation on multiple chapel greenhouses is to provide, on the sides of the film and in the lengthwise direction of the greenhouse, sheaths secured to the film in which are generally flat bars. There is provided along the alignment of the fixing of the arches along the gutters, an elongated structure comprising claws or lugs for locking the bars, for example fingers directed towards the outside of the arch.

This type of installation is attractive because the installation is quick and easy and therefore requires little labor time. But as there are fixed structures in the gutters to fix the films, it is imperative that the width of the film meets very strict dimensions. The tolerance on film widths of the order of 6.5 meters or more is only 2 cm.

This system is simple to implement on the greenhouse, efficient and reliable. However, the production of the film is partly artisanal and therefore time-consuming and costly. Indeed, the dimensional tolerance constraint obliges to form the sheaths by hand after the film has been manufactured. If the width is insufficient, the film cannot be installed. If the width is too large, the film floats and will not fit properly on the greenhouse. In addition, the implementation can only be done for greenhouses whose structure is specially designed for this type of roofing.

It would therefore be desirable to have a device allowing a good tension of the film during the initial assembly and advantageously to be able to tighten the films. This film should moreover advantageously be easy to install. It should also advantageously be adaptable on fixed structures of different width to allow mass production by avoiding customization. However after long research the applicant discovered a simple and effective process to achieve the above objectives.

This is why the present application relates to a greenhouse comprising arches covered with at least one film, characterized in that the film or the main film in the case of covering with several films, comprises at least one sheath (called " median ") in which is threaded a rod made integral with said film, said sheath being installed longitudinally over the entire length of the greenhouse. By simple rotation of the rod on itself, the strips of film located on either side of the sheath are rotated around the rod, which therefore wind around said rod.

When a single sheath is provided, it is preferably installed in the middle on the film to balance the tension of each strip.

In the case of the use of films having good elasticity, it is possible to center the sheath to delimit two strips of unequal width while continuing to benefit from an almost balanced tension.

Several such devices can be provided installed in parallel on a greenhouse, for example 4 or 5, but preferably 2 or 3 such devices.

The installation of several such devices associated with winding rods of a certain thickness, for example between 3 and 10 cm, in particular 3 and 6 cm allows, in the case of the installation of a second film, create an air layer between the two films, which has a particularly insulating effect. In general, in such cases, the devices will preferably be installed so as to define strips of film of approximately equal width to balance the tension of each strip.

The use of more than one device provides the film with additional longitudinal supports, in addition to the transverse supports constituted by the arches which form the upper structure of the greenhouses. In addition, the tension of the film is better distributed over the width, which places less stress on the film fixing lines.

The sheath (s) may be produced by any known means, for example by sewing, by gluing and preferably by welding. We can for example weld the film on itself or even bring a strip of material that will be fixed to the film in particular by welding.

Each sheath may for example have a width of 5 cm, which corresponds to the possibility of introducing a circular rod of approximately 3 cm in diameter. This width could for example be between 1, 5 and 10 cm, advantageously between 2 and 8 cm, preferably between 3 and 6 cm, in particular between 4 and 5 cm, in general depending on the length of the greenhouse. and the nature of the stem.

Under preferential conditions for implementing the invention, the sheath or at least one of the sheaths has a cable inside, in particular to participate in the drawing of the tube strands during their installation. For example, an operator can pull a strand of tube while the other pushes the strands to be threaded into the sheath, which makes it possible to increase the length of the strands and therefore to decrease their number. In yet other preferential conditions for implementing the invention, the sheath or at least one of the sheaths includes slots, in particular regularly spaced preferably by the length of a strand for threading each strand therein.

The winding rod can be made of solid material such as wood, plastics or metal. Under preferential conditions for implementing the invention, the winding rod will or includes a hollow tube, for example for drawing an electric line.

The rod threaded into the sheath will preferably be made in several strands. These can for example be threaded into each other for example as tent pillars and provided at their ends with a means to prevent their relative pivoting in the case of the use of cylindrical rods, such as a bayonet system . Taking into account that the winding will always be in the same direction to stretch the film, one can provide a screw at one end and a nut at the other. This problem of relative pivoting does not arise with the use of rods of non-circular section, for example square, rectangular or hexagonal. It is possible in particular to use rods of circular section having along their length a groove which, in addition, makes it possible to fix the film by using a rod, for example made of rubber. By acting on one end of the rod, the whole of the latter is rotated.

At least one of the ends of the winding rod is advantageously provided with a device to facilitate its rotation in order to tension the film. Thus, for example, a handle or a crank may or may not be removable, a locking system with non-return pawl, pinions or a grooved wheel associated with a motor, etc. It is also possible to provide very simple devices such as a simple perforation formed diametrically in the rod to allow the passage of an actuatable bar with one or two hands or a simple axial hole of shape adapted to use for example a male key or even provide an externally square or hexagonal end to cooperate with a wrench, flat or tube or with a socket or a torque wrench to give a maximum particular tension. It is also possible to provide a pulley or a universal joint at the end of the rod for actuating the rod, for example using a tractor engine.

When sufficient tension is obtained, the rod can then be locked in this position, for example thanks to the end hoops of the structure. For example, it is possible to block a bar which can be actuated with two hands mentioned above, inserted diametrically into the rod against the corresponding end hoop, in particular by tying together the rod and the hoop, to cite a simple locking means.

In the case of very long greenhouses or using overlapping strips, several independent winding rods can be used.

To allow its entrainment, the film must be secured to the rod. This immobilization can be done by simple winding. After, for example, one or two dead turns, the film self-tightens on itself. However, under preferential conditions for implementing the invention, this immobilization is real and will be done by the use of any known means, in particular gluing, stapling, clipping, riveting or welding. It is preferable to provide, from time to time on the film, by way of illustration every 3 or 4 m, a clip or a small jumper, for example made of steel adapted to the diameter of the tube, which will clamp the sheath against the tube. A limited number of fasteners may be sufficient to secure the tube to the sheath since after a dead turn the film will be driven without problem. It is preferable to fix the film to the rod regularly and preferably over the entire length in order to have the most regular tensions possible and to avoid embrittlement of the film. For example in the case of riveting, an elongated blade can be provided between the head of the rivet and the film to balance the stresses during winding. The lateral blockages of the film, whatever the level of the desired fixing line on the arch (on the gutter, on the ground or in the intermediate position) can be achieved by any known technique such as for example that of clipping along a continuous line in special clips offered by greenhouse manufacturers. In yet other preferential conditions for implementing the invention, the film also comprises sheaths provided at the lateral edges of the film, preferably over the entire length of the film. Thus one benefits from the advantages of ease and speed and therefore reduced labor time of the prior art set out above without having the disadvantage of strict manufacturing tolerances.

The different sheaths ("median (s)" and "lateral (s)") are thus substantially parallel to one another.

Depending on the type of greenhouse, the arches go to the ground (tunnels) or not (multiple tunnels, chapels or multiple chapels).

Although it is possible to use a double film, for example to form the sheaths by welding or sewing the two films together, always under other preferential conditions for implementing the invention, the film is simple. A film according to the invention can be produced in particular as follows:

The film is welded in line (that is to say after the film has been manufactured and before it is wound up, possibly after folding in half or more on itself). In particular, it is possible, in order to obtain the sheaths, to weld the film on itself along a parallel line provided a few centimeters inward of the folds coming to be wound at the edge of the coil. Depending on the applications, a weld may be made at each fold, or only at a few, or even a single fold.

The present application also relates to a greenhouse film characterized in that it comprises at least one sheath provided over the entire length of the film at a distance from its lateral edges.

Under preferential conditions for implementing the invention, the film also comprises sheaths provided at the lateral edges of the film, preferably over the entire length of the film.

In other preferred conditions for implementing the invention, the film also comprises at least one additional sheath provided parallel to the other sheaths, preferably over the entire length of the film.

In still other preferential conditions for implementing the invention, the film comprises two sheaths (called "lateral") provided at the lateral edges of the film. And in addition from 1 to 10, advantageously from 1 to 8 , of preferably from 1 to 5, in particular from 1 to 3, very particularly 1 additional sheath (s) (called "medians").

The width of a film according to the invention will generally vary from 2 m to 15 m. advantageously from 5 m to 10 m. It may have a length for example of around 100 to 500 m, in particular 200 to 400 m, advantageously around 350 m for a width of 15 m. For widths of 2 m, one could have a length for example of approximately up to 3000 m and for widths going from 5 m to 10 m the lengths of coils could go for example from 500 m to more than 1000 m. Its thickness is conventional for greenhouses. The films which are the subject of the present invention are preferably transparent over more than 70% of their surface, in particular over more than 80% of their surface, particularly over more than 90% of their surface and very particularly entirely transparent.

The films which are the subject of the present invention have very advantageous properties. They allow in particular to simply stretch a film on a greenhouse. They justify the use of the films described above, for stretching a film on a greenhouse.

This is why the present application also relates to a method for stretching a film on a greenhouse comprising hoops, characterized by the following steps:

a film is installed on the arches comprising at least one sheath provided over the entire length of the film,

- the sides of the film are blocked for example at ground level or in gutters, - a rod is threaded into the sheath over the entire length of the film,

- the sheath and the rod are fixed together to make it integral with the film,

- the film is wound on the rod by rotating the latter in the sheath,

- the rod is locked in the chosen position. You can thread the rod before or after blocking the sides of the film.

In some greenhouses, such as those with multiple chapels, an opening is provided over all or part of its length. The tensioning bar by winding can then be the hinge of the opening which, once the film is stretched, can be fixed to the structure from the inside. We can finally use a tension bar in its sheath not to stretch the film but to wind it up for example to partially or completely uncover the greenhouse. This is how the present invention can be implemented for winding and partially or completely discovering the greenhouse in the case of greenhouses comprising films of which a longitudinal edge, situated at the peak of the greenhouse or not, is not fixed but mobile and generally maintained under traction, like Richel® discoverable greenhouses (Eygalières-France).

The preferential conditions for implementing and producing the greenhouses described above also apply to the other objects of the invention referred to above, in particular to greenhouse films and to the process for stretching a film on a greenhouse.

The invention will be better understood if reference is made to the appended drawings in which

- Figure 1 shows a perspective view of a greenhouse of the type with multiple chapels.

- Figure 2 shows a film according to the invention installed flat and comprising several variants of sheaths. - Figure 3 shows a perspective view of a rod installed in a sheath of a film according to the invention installed on a greenhouse

- Figure 4 shows a perspective view of a lateral attachment of a film according to the invention.

FIG. 1 represents a greenhouse 1 comprising arches 2 covered with a film 3.

This film includes a sheath 4 in which is installed a rod 5 which has been made integral with the film 3 by using clips not shown in this figure. This sheath 4 extends longitudinally over the entire length of the greenhouse 1.

The greenhouse shown here is of the multiple chapel type.

Its frame includes uprights 6 surmounted by gutters 7 for the evacuation of rainwater, as well as arches 2. The longitudinal edges of the film also include sheaths into which other rods are inserted, serving to fix the film to the frame.

In Figure 2 we can distinguish in this example of film according to the invention 2 lateral sheaths 8 contributing to the fixing of the film 3 on the structure or on the ground.

These lateral sheaths are constituted by a lateral flap welded to the film itself. One can also consider welding sheaths already formed on the edges of the film 3. The film 3 comprises two sheaths 4a and 4b, called "medians" because they are located between the lateral sheaths. The middle sheath 4a was formed by folding the film for, in cross section, constituting a loop, and by carrying out a welding over the entire length of the film 3. The edges of the film called lateral edges are those situated along the lateral sheaths 8. The middle sheath 4b has been formed in bringing a strip 9 elongated on the film in its length and by welding its lateral edges.

In FIG. 3, we can observe the film 3 installed on arches 2. A sheath of the type shown in 4b above was formed by attaching a strip 9 welded to the film 3. We can see the welds 10 on the edges of strip 9 added. In the sheath thus formed, a rod 5 has been slid essentially consisting of a hollow tube. Two variants for fixing the film to the rod have been shown. In the first variant, a locking clip 11 has been provided to clamp the film against the rod. In the second variant, the fixing was carried out by using pop rivets 12; a reinforcing blade 13 has been provided between the head of the rivet and the film to distribute the forces during winding. At one end of the rod 5, a hexagonal head 14 has been provided to cooperate with a complementary socket installed in the following rod, the other end of which also includes a hexagonal head.

This rod is an end rod. It has been provided with a system to facilitate winding. The system shown here is very simple, since there is simply provided a winding bar 15 to serve as a lever. This winding bar 15 is installed in a bore 16 installed diametrically towards the end of the rod located towards the outside of the greenhouse, beyond the end of the film. It can be bent to be used as a crank.

To tension the film 3 in accordance with the method according to the invention, it suffices to drive the rod 5 in rotation by acting on the winding bar 15, then to block it when the desired tension is reached. This can be easily done for example, by blocking the winding bar 15 by connecting it to the arch 2. To refine the adjustment of the tension of the film 3 with such a device, it is possible to provide several bores 16 according to oriented diameters. differently, which makes it possible to block the winding bar 15 without operating a full half-turn of the rod 5.

In FIG. 4, it can be seen that the film 3 is provided with a lateral sheath 8 into which a flattened blade 17 is inserted. An upper edge 18 of a gutter 7 is provided with fingers 19 which make it possible to block the flattened blade 17 and therefore laterally block the film 3.

Claims

1. A greenhouse (1) comprising arches (2) covered with at least one film (3), characterized in that the film (3) or the main film in the case of overlapping by several films, comprises at least one sheath (4) in which is threaded a rod (5) made integral with said film (3), said sheath (4) being installed longitudinally over the entire length of the greenhouse (1).

2. A greenhouse according to claim 1, characterized in that the film comprises a single sheath (4) installed in the middle on the film (3).

3. A greenhouse according to claim 1 or 2, characterized in that it comprises 2 or 3 sheaths (4) installed parallel to the greenhouse (1).

4. A greenhouse according to one of claims 1 to 3, characterized in that the winding rods (5) have a thickness ranging from 3 to 10 cm.

5. A greenhouse according to one of claims 1 to 4, characterized in that each sheath (4) has a width between 1, 5 and 10 cm.

6. A greenhouse according to one of claims 1 to 5, characterized in that the sheath (4) or at least one of the sheaths has inside a cable.

7. A greenhouse according to one of claims 1 to 6, characterized in that the rod (5) consists of several strands and in that the sheath (4) or at least one of the sheaths has regularly spaced slots preferably the length of a strand to thread each strand.

8. A greenhouse according to one of claims 1 to 7, characterized in that the rod (5) comprises a hollow tube.

9. A greenhouse according to one of claims 1 to 8, characterized in that the rod (5) is made of several strands.

10. A greenhouse according to one of claims 1 to 8, characterized in that at least one of the ends of the winding rod (5) is provided with a device (44) to facilitate its rotation in order to tension the film (3).

11. A greenhouse according to one of claims 1 to 10, characterized in that the film (3) is secured to the rod (5) for example by gluing, stapling, clipping, riveting or welding.

12. A greenhouse according to one of claims 1 to 11, characterized in that the film (3) comprises sheaths (8) provided at the lateral edges of the film (3).

13. A greenhouse film characterized in that it comprises two sheaths (8) (called "lateral") provided at the lateral edges of the film, and in addition from 1 to 10, sheath (s) (4) (called "medians") provided over the entire length of the film (3) at a distance from its lateral edges.

14. A greenhouse film according to claim 13, characterized in that sheaths (8) constituted by a lateral flap of said film welded to the film itself are provided at the lateral edges of said film (3).

15. A method for stretching a film on a greenhouse comprising arches, characterized by the following steps: - a film (3) comprising at least one sheath (4) provided over the entire length of the film is installed on the arches (2) (3),

- we block the sides of the film (3),

- a rod (5) is threaded into the sheath (4) over the entire length of the film

(3), - the sheath (4) and the rod (5) are fixed together to make it integral with the film (3),

- the film (3) is wound on the rod (5) by rotating the latter in the sheath (4),

- the rod (5) is blocked in the chosen position.