LIGHTWEIGHT CONSTRUCTION

Abstract: A lightweight construction, especially a greenhouse structure, comprises a plurality of pillars (12)arranged at the periphery of an area of said lightweight construction, said pillars (12) extending obliquely and outwardly so that an upper end (22) of said pillars (12) lies substantially in a vertical plane passing through a respective area border. According to the invention at least one of said pillars (12) comprises a supporting element (14), said supporting element being mounted onto said pillar (12) so as to define a predetermined inclination angle of said pillar (12).

Description: Lightweight construction Introduction The present invention relates to a lightweight construction, as e.g. a greenhouse structure, especially a modular greenhouse. Lightweight constructions as e.g. modular greenhouse constructions are well known and commonly used where large agriculture surfaces have to be cov- ered. Such a greenhouse structure generally comprises a plurality of uprights, which are uniformly distributed over an area of the greenhouse. At the periphery of said greenhouse area, pillars are mounted obliquely to extend outwardly in a predetermined angle, wherein the pillars are arranged so that their upper end lies substantially in a vertical plane passing through the area border. These pillars are braced outwardly to ground anchors and inwardly to a corresponding pillar of the opposite side of the greenhouse, whereby the bracing wire passes over the different uprights arranged between the two opposite pillars. By securely tightening the wires used to fasten the different pillars together, statically self-contained cells are formed, which can be lined up in both lateral and longitudinal direction to form a single closed structure. With such a modular system, greenhouse structures can be assembled, which cover surfaces of several hectares. A greenhouse of this kind is e.g. disclosed in FR-A-2209494. The assembly of a greenhouse of this kind starts with the mounting of the outer pillars at the corners of the surface to be covered. These corner pillars have to be mounted so as to extend obliquely outwardly at a predetermined angle. After these corner pillars are placed, the intermediate outer pillars are individually mounted in line, whereby these plies have to be equally oriented, so that straight sides are fo " fmed. Then the inner uprights are placed at the predetermined locations and braced together with metal wires at their upper ends. Finally, the so formed body structure is covered with a plastic sheet to close the greenhouse. The problem arising with this method is that the mounting of the oblique outer pillars, i.e. the lining up, the orientation and the bracing of these pillars, requires very high-qualified mounting personnel and is furthermore very time consuming. It follows that the assembly of a greenhouse according to this method is rather expensive. Object of the invention The object of the present invention is to provide a greenhouse structure, which is easier to assemble. Generai description of the invention In order to overcome the above-mentioned problem, the present invention proposes a lightweight construction, especially a greenhouse structure, which comprises a plurality of pillars arranged at the periphery of an area of said lightweight construction, said pillars extending obliquely and outwardly so that an upper end of said pillars lies substantially in a vertical plane passing through a respective area border. According to the invention at least one of said pillars comprises a supporting element, said supporting element being mounted onto said pillar so as to define a predetermined inclination angle of said pillar. The pillars of the present invention can be easily prefabricated before transporting them to the greenhouse construction site. It is clear that when assembling the greenhouse, these prefabricated pillars only have to be aligned and suitably distanced in order to define the outer border of the greenhouse. The pillars having a predefined inclination, no time consuming inclination adjustment is required. Only the orientation in a direction substantially perpendicular to said supporting structure has to be individually adjusted for each pillar, which does not cause any difficulties to the one skilled in the art. The present invention therefore enables a very simple method of correctly mounting the outer pillars of a lightweight construction. This simplified assembly method reduces the time necessary for mounting these pillars by more than a half. Moreover, the simple steps of the method can be executed by ordinarily qualified mounting personnel, which are less expensive than highly qualified specialists. It follows that the method according to the present invention substantially reduces the mounting time and the overall construction expenses for a known greenhouse construction. In a first embodiment, said supporting element comprises a horizontal bar, said horizontal bar being mounted adjacent a lower end of said pillar in such a way that the angle between said pillar and said horizontal bar equals said inclination angle of said pillar. If the pillar is mounted in such a way, that the horizontal bar extends horizontally, the predetermined inclination of the pillar is given. The pillar may e.g. be mounted in such a way that the horizontal bar rests on the ground. In a second embodiment, the said supporting element comprises a vertical bar, said vertical bar being mounted onto said pillar so that the angle between said pillar and said vertical bar equals an angle complementary to said inclination angle of said pillar. The vertical bar can e.g. have a length such that the pillar has the right inclination if the lower end of the bar touches the ground. This is the case when the length of the vertical bar equals the length of the vertical leg of a rectangular triangle defined by said pillar, said vertical bar and an imaginary horizontal line connecting a lower end of said pillar to said vertical bar. It has to be noted that the vertical bar may be mounted on the pillar at any suitable location thereof. However a preferred location is adjacent an upper end of the pillar, since this embodiment shows the better statical characteristics. It will be apparent for the one skilled in the art that the two embodiments described above can be easily combined. In this case the supporting element comprising a vertical bar and a horizontal bar, both connected with their respective first end to the pillar and connected together at their respective second ends. The supporting structure thus forms a triangle together with the pillar, which provides a very high stability to the element. It has to be noted that a supporting element comprising a vertical bar mounted on an upper end of the pillar has a double function. In fact, besides its function as auxiliary supporting structure for supporting the upper end of the pillars during assembly of the construction, the vertical bars advantageously also support the side wall plastic foil of the finished greenhouse. In this way high wind loads on the plastic foil can be absorbed by the vertical bars and deviated into the foundation. Accordingly, the supporting element also has a supporting and protecting function for the cover material of the lightweight construction. In a preferred embodiment, the vertical bar comprises an anchoring pole, said anchoring pole having a length greater than the length of the vertical leg of a rectangular triangle defined by said pillar, said anchoring pole and an imaginary horizontal line connecting a lower end of said pillar to said vertical leg. It follows that in this case the anchoring pole extends beyond the point of intersection of the pole and the horizontal line. This lower end of the anchoring pole can thus be used to fixedly mount the pillar by digging the anchor into the ground or by embedding into a concrete base, which can be easily formed by filling a suitable trench with concrete. It has to be noted that in this embodiment, the supporting structure assure a further function. In fact, if securely fixed into a concrete foundation, the anchoring pole can advantageously deviate any upwardly directed traction forces into the foundation. Such upwardly directed traction forces can be exerted e.g. by the bracing wires connecting the pillar to a corresponding pillar of the opposite side of the greenhouse or by wind. The correct mounting of the pillar and the associated anchoring pole can be achieved by controlling the vertical orientation of the anchoring pole. In a preferred to alleviate this adjustment, the anchoring pole may comprise at least one mark at the intersection between said anchoring pole and said imaginary horizontal line, said mark indicating the digging depth of said anchoring pole. By embedding the anchoring pole exactly up to the mark, a vertical arrangement of the anchoring pole and thus a correct inclination of the pillar is easily achieved. In a preferred embodiment, each of said pillars comprises receiving means for receiving a horizontal distance element. The distance element preferably is a horizontal distance bar for mounting between the upper ends of two adjacent pillars. The assembly of the greenhouse is further simplified by these distance bars since the distance elements define the correct spacing between two adjacent pillars. If the distance bars are mounted on the upper ends of the pillars, these distance bars further define an upper frame of the greenhouse structure, which provides an improved rigidity of the greenhouse. The pillars advantageously comprise a pedestal mounted on a lower end of said pillar. It follows that no separate pedestal for the pillar has to be provided, thus further reducing the mounting time for the entire structure. It has to be noted that, after the mounting of the peripheral pillars in the way described above, each pillar may be braced to a corresponding pillar at the opposite side of the greenhouse by means of wires. After this step, the uprights necessary for supporting the roof of the greenhouse are mounted on their respective positions between the outer pillars, the uprights lifting the bracing wires so that the wires are further tightened. Detailed description with respect to the figures The present invention will be more apparent from the following description of a not limiting embodiment with reference to the attached drawings, wherein Fig.1 : shows a preferred embodiment of a pillar of a greenhouse; Fig.2: illustrates the method for assembling the greenhouse structure; and Fig.3: shows further embodiments of pillars with supporting element. Fig. 1 shows preferred embodiment of a prefabricated pillar element 10 of a greenhouse according to the invention. The pillar element 10 comprises a pillar 12 for mounting obliquely at a periphery of a greenhouse structure so as to extend outwardly in a predetermined angle, and a supporting element 14 for conferring a predetermined inclination angle α to the pillar 12. In the shown embodiment, the supporting structure 14 comprises an anchoring pole 16 mounted on an upper end of the pillar 12 in such a way, that the anchoring pole and the pillar define an angle β which corresponds to the complementary angle of α, i.e. β = 90° - α. The supporting structure further comprises an horizontal bar 18 mounted between a lower end of said pillar 12 and the anchoring pole 16 so that the pillar 12, the anchoring pole 16 and the horizontal bar 18 define an rectangular triangle. This horizontal bar thus confers an improved stiffness to the pillar element 10. The anchoring pole has a length which is greater than the vertical leg of the triangle defined by the different elements. It follows that the lower end 20 of the anchoring pole extends beyond the point of intersection of the pole and the horizontal bar. This lower end of the anchoring pole may be used to fixedly mount the pillar by digging the anchor into the ground or by embedding into a concrete base. For this purpose, the lower end 20 of the anchoring pole may be further provided with an specific texture, i.e. notches or the like, for enhancing the adherence to the ground or concrete. At the upper end, the pillar 12 may be provided with receiving means for receiving a distance element used to place adjacent poles at a suitable distance. This receiving means can e.g. comprise a horizontal sleeve 22 for receiving a spacer tube. The assembly of the greenhouse according to the invention is illustrated in fig. 2. After excavating a suitable trench 30 surrounding the area of the greenhouse to be mounted, the different outer pillar elements 10 are consecutively aligned starting from one corner. The pillar elements are arranged in such a way that the lower ends of the anchoring poles extend into the trench 30. The trench thereby provides for a first reference line for the lateral alignment of the pillar elements. A more exact alignment can be achieved by using a laser based aligning equipment, which can also be used for vertical alignment. The pillars are subsequently mounted, whereby spacer tubes 32 are placed between two adjacent pillars. These spacer tubes easily ensure an equal spacing between the different pillars. As soon as a pillar is mounted, the trench may be filled with stones and earth or with concrete in order to embed the lower end of the anchoring pole, thereby fixing the position of the pillar. After the peripheral row of pillars has been mounted, each pillar is braced to the corresponding pillar at the opposite side of the greenhouse. Subsequently the uprights necessary for supporting the roof of the greenhouse are erected at the appropriate positions between the pillars, so that a substantially regular grid is formed. The pillars are thereby mounted so as to lift the bracing cables thus further tensioning these cables. The greenhouse structure is now finished and can be covered e.g. by a suitable plastic foil. Further embodiments of pillars with supporting element are shown in fig. 3. In these embodiments, the supporting element is configured to provide a support in at least two points lying on either side of a vertical plane containing the inclined pillar. It follows that the three-dimensional orientation of the pillars shown in fig. 3 is entirely predetermined. In the embodiment shown in fig. 3 a), the said supporting element comprises two oblique bars 34 mounted onto said pillar 12, one of said oblique bars being mounted on either side of a imaginary vertical plane containing said pillar. As shown, the oblique bars 34 are mounted in a central region of the pillar 12 and extend downwardly in such a way that the lower ends of said bars and the lower end of said pillar define the corners of an horizontal triangle. Fig. 3 b) and c) illustrate embodiments of pillars, in which the supporting element comprises a supporting base 36 which is mounted adjacent a lower end of said pillar 12 in such a way that the angle between said pillar and said supporting base equals said inclination angle of said pillar. The supporting base 36 may simply comprise a plate mounted on the lower end of the pillar. In the shown embodiments, the supporting base 36 comprises several rods 38 extending outwardly from said lower end of said pillar in such a way that the outer ends of said rods substantially lie in a plane which is cut by said pillar in an angle equal to said inclination angle. It should be noted, that the rods may be inclined with respect to said plane (shown in fig. 3 b)) or may entirely lie in said plane (shown in fig. 3 c)). Independent of the embodiment, the outer ends of the rods may be connected to an annular collar 40 in order to increase the stiffness of the supporting base 36. List of reference numerals 10 pillar element 12 pillar 14 supporting structure or element 16 anchoring pole 18 horizontal bar 20 lower end of the anchoring pole 22 horizontal sleeve 30 suitable trench 32 spacer tubes 34 oblique bar 36 supporting base 38 rods 40 annular collar

Claims: Claims 1. Lightweight construction, especially a greenhouse structure, said lightweight construction comprising a plurality of pillars arranged at the periphery of an area of said lightweight construction, said pillars extending obliquely and outwardly so that an upper end of said pillars lies substantially in a vertical plane passing through a respective area border, characterised in that at least one of said pillars comprises a supporting element, said supporting element being mounted onto said pillar so as to define a predetermined inclination angle of said pillar. 2. Lightweight construction according to claim 1 , wherein said supporting element comprises a horizontal bar, said horizontal bar being mounted adjacent a lower end of said pillar in such a way that the angle between said pillar and said horizontal bar equals said inclination angle of said pillar. 3. Lightweight construction according to claim 1 or 2, wherein said supporting element comprises a vertical bar, said vertical bar being mounted onto said pillar so that the angle between said pillar and said vertical bar equals an angle complementary to said inclination angle of said pillar. 4. Lightweight construction according to claim 3, wherein said vertical bar comprises an anchoring pole, said anchoring pole having a length greater than the length of the vertical leg of a rectangular triangle defined by said pillar, said anchoring pole and an imaginary horizontal line connecting a lower end of said pillar to said vertical leg. 5. Lightweight construction according to claim 4, wherein said anchoring pole comprises at least one mark at the intersection between said anchoring pole and said imaginary horizontal line, said mark indicating the digging depth of said anchoring pole. 6. Lightweight construction according to claim 1 , wherein said supporting element comprises two oblique bars mounted onto said pillar, one of said oblique bars being mounted on either side of a imaginary vertical plane containing said pillar, said oblique bars extending downwardly in such a way that the lower ends of said bars and the lower end of said pillar define the corners of an horizontal triangle. 7. Lightweight construction according to claim 1 , wherein said supporting element comprises a supporting base, said supporting base being mounted adjacent a lower end of said pillar in such a way that the angle between said pillar and said supporting base equals said inclination angle of said pillar. 8. Lightweight construction according to claim 7, wherein said supporting base comprises several rods extending outwardly from said lower end of said pillar in such a way that the outer ends of said rods substantially lie in a plane which is cut by said pillar in an angle equal to said inclination angle. 9. Lightweight construction according to any one of claims 1 to 8, wherein said pillar comprises receiving means for receiving a horizontal distance element. 10. Lightweight construction according to claim 9, wherein said distance element is a horizontal distance bar for mounting between the upper ends of two adjacent pillars. 11. Lightweight construction according to any one of claims 1 to 10, wherein said pillar comprises a pedestal mounted on a lower end of said pillar.

Inventors: KUENZEL THOMAS, KUENZEL, THOMAS
Applicants: KUENZEL OHG, KUENZEL THOMAS, TREFILARBED BISSEN S A, KUENZEL, THOMAS, TREFILARBED BISSEN S.A.
Application year: 2001
Main classification: A01G9
IPC codes: A01G9, E04H15