FR2692926A1 - Process for assembling light structures - comprises hollow moulded polymer components, uprights with holes for horizontal tubes bearing roof sheets and grooved wall blocks - Google Patents

Abstract

A process for assembling light structures of approximate human size, consists of putting together various hollow moulded polymer parts which form uprights (8) with round holes (3) for horizontally placed tubes (9). The walls are made of hollow blocks (13) with halfround grooves to take the tubes. Stoppers (15) are used to plug the holes in the uprights, not being used for the horizontal tubes. The roof consists of corrugated polyester sheets resting on horizontal beams. The same components are used for constructing seesaws, swings and rings. USE/ADVANTAGES - Suitable for children's playgrounds and temporary structures.

Description

METHOD AND SYSTEM FOR CONSTRUCTING LIGHTWEIGHT STRUCTURES
USING ROTOMOLD POLYMERIC ELEMENTS
DESCRIPTION
FIELD OF THE INVENTION
The invention relates to the construction of very diverse structures, of human size, light, having a modular character to the construction and whose mechanical resistance does not necessarily have to be good. We think in particular of various games of gardens and entertainment parks for children, such as porticoes, tubular scaffolding structures on which they can climb, swings, ... It can also concern buildings more or less temporary or temporary.

 The invention relates on the other hand to the manufacture of plastic objects, such as polymer, rotomolded which then constitute the elements of the structure.

PRIOR ART AND PROBLEM POSED
It is common to set up amusement parks or public gardens in which children can find one or more structures constituting attractive collective or individual games, not only because of the fun or distracting function of the game, but also through colorful and cheerful aspect of the structure.

 The object of the invention is to make available to a large part of public or private establishments, a construction system allowing any unskilled person to build by means of light plastic elementary objects, varied colors, very diverse structures such as the structure of a house to climb, a portico in the shape of a cage on which children can climb, a swing, a ring, ...

OBJECT OF THE INVENTION
To this end, the first main object of the invention is a method of building light structures of human size consisting of assembling different polymer elements, light, rotomolded and hollow, having complementary shapes to be able to assemble with each other and form a structure.

The second main object of the invention is a light structure construction system for implementing the method summarized above and having as main elements
- beams in which appear circular fixing holes of determined diameter D
- Tubes with an external diameter corresponding to the determined diameter D of the holes, so that they can be inserted inside these holes.

 They can be completed with wall elements in the form of panels, at least two opposite parallel sections of which have a longitudinal recess complementary to the outside diameter of the tubes in order to be able to form sections of walls on a structure of several parallel tubes.

 It is also planned to use rotomolded polymer plugs to plug the unused holes of the beams.

 Polyester sheets can constitute the cover of a frame-like structure composed of at least two parallel beams connected by several tubes and on which the sheets can be supported thanks to one side of the corrugated sheet of shape complementary to the tubes for position the sheets relative to them.

 In order to form a table, it is possible to use a rotomolded polymer panel having a usable flat surface and an opposite surface provided with holes or feet into which rotomolded polymer feet are inserted having a section complementary to these holes.

 An example of a game consists of a swing consisting of a stable support in rotomolded polymer and serving as a yoke for a horizontal axis consisting of a section of tube around which can be pivotally mounted a beam constituting the pendulum of the swing.

 It is advantageous to have rigid splices to fix two beams perpendicular to one another and thus ensure their maintenance between them.

 Longitudinal reinforcements can be housed inside the beams to stiffen the structure thus designed.

 Rotomolded or blown plastic nails can be used to secure the tubes in the beams.

LIST OF FIGURES
The invention and its various technical characteristics will be better understood on reading the following description, accompanied by several figures representing respectively
- Figure 1, an example of a mold used to manufacture a beam forming part of the invention
- Figure 2, the same reinforced beam;
- Figure 3, a structure according to the invention in the form of a house
- Figure 4, a structure according to the invention in the form of a ring;
- Figure 5, a structure according to the invention in the form of a simple swing
- Figure 6, a structure according to the invention in the form of an American swing
- Figures 7A, 7B and 7C, in section, several embodiments of possible attachments of a tube on a beam according to the invention.

DETAILED DESCRIPTION OF SEVERAL MODES OF
REALIZATION OF THE INVENTION
One of the techniques for manufacturing hollow plastic objects is rotational molding. We know in fact by this technique to manufacture many large various objects in polyethylene, such as canoes, kayaks, windsurfers, boats, and different types of containers, such as septic tanks.

 This rotational molding technique consists of providing a hollow mold consisting of two separable half-molds joining along a junction surface or longitudinal joint plane. The mold is preferably metallic and must be heated by external heating means.

The mold is adapted on a mobile support device intended to cause rotational movements along a longitudinal axis and along a transverse axis. Then introduced into the mold a sufficient amount of polyethylene supplemented with dye and other materials possibly intended to form the molded object.

The mold is then closed. During slow rotations provided by the support device, the mold is heated and the polyethylene gradually melts, spreading evenly over the entire internal surface of the mold.

Indeed, the rotations are chosen ~ so that this distribution is substantially equal over the entire internal surface of the mold. After cooling, the two half-molds are separated and the object thus molded is taken out.

It is understood that the internal surface of the mold intended to form the external surface of the object must have a good quality surface condition and a particularly regular surface. The absence of cores in the mold for the production of hollow objects is one of the main advantages of rotational molding.

 This rotational molding technique therefore makes it possible to manufacture hollow plastic elements, light and bulky, such as a canoe kayak, a buoy, a boat or any container, such as a septic tank of several cubic meters.

 Figure 1 allows to see in perspective and in section a rotational molding mold for the manufacture of a beam used in the system according to the invention.

 Indeed, the beam thus rotomolded constitutes an essential element of the system and of the construction method according to the invention. It is a beam several meters long consisting mainly of a polymer, for example polyethylene, and dyes.

Of course, this beam is hollow and is therefore very light. Its section is preferably rectangular.

 To be able to participate in the fixing of other elements of the structure according to the invention, along at least one axis perpendicular to two opposite faces, this beam has a series of holes 3 into which tubes will be introduced whose diameter corresponds to the diameter D holes 3.

 The mold consists of two half-molds 1 and 2.

As can be seen in this figure 1, the joint plane of these two half-molds 1 and 2 is not placed in the middle of the height of the beam, but is placed along two opposite edges. Indeed, given the fact that it is relatively inconvenient to demold a polyethylene form molded in a cavity, it turns out to be very advantageous not to constitute each of the two half-molds by each a cavity comprising internal surfaces in opposite, but simply with two perpendicular internal surfaces.

 As illustrated in FIG. 1, mold release tools 5 can be provided to separate the two half-molds 1 and 2 which tend to be kept glued by the adhesion of the still hot polyethylene with the internal walls of the two half-molds 1 and 2.

 The holes 3 can be provided on several sides of the beam and are obtained by means of cores 4 placed at these locations. It may be noted that it is also advantageous, to facilitate demolding, to provide these slightly conical cores. Of course, their end corresponding to the molding of the hole 3 preferably has a cylindrical surface.

 A beam thus produced can measure twenty meters long. It is of course understood that, in the case where it is desired to build relatively solid structures, it is advantageous to stiffen such beams.

 FIG. 2 shows a reinforcement 7 inserted inside a beam 8. As soon as the latter has lateral holes 3 centered in the middle of the beam 8, the reinforcement 7 can only be placed laterally at the inside the section of the beam 8.

The reinforcements 7 can therefore be made up of steel beams thus consolidating beams involved in the construction of load-bearing structures which have to support loads or constitute resistant buildings.

 To better highlight the utilitarian nature of the elements thus manufactured, we refer to Figure 3.

 This represents a structure in the form of a house constructed using sections of beams 8 and tubes 9. The latter are placed in the lateral holes 3 of the beams 8 and are therefore perpendicular to the latter.

They can thus constitute the framework of a wall of the house whose corners where the angles consist of sections of beams 8. Although the diameter of the holes 3 of the beams 8 corresponds to the diameter of the tubes 9, a fixing can be carried out as illustrated in Figures 7A, 7B and 7C.

 It is thus conceivable that such a structure built on a human scale, that is to say whose height can be between one meter fifty and three meters, could constitute a climbing instrument for children or a house called " to climb ". Without losing sight of the fact that these elements are obtained by rotational molding of colored polyethylene, the structure thus formed can have a very cheerful appearance by using different colors and take on a very attractive side with children. We then understand the use of such a structure in a leisure amusement park.

 Of course, this structure must have a minimum rigidity to support the weight and the forces due to the movements of several people on the tubes 9 and on the beams 8. In order to stiffen such a structure, it is possible to reinforce by a splice 10 each corner formed by the juxtaposition of two beams 8A and 8B forming an angle. Indeed, to constitute the frame of a roof, it is advantageous to have a beam 8B inclined with respect to a vertical beam 8A. The splint 10 then ensures the maintenance of this juxtaposition.

 I1 can be the same with a fishplate 11 placed at the top of such a frame joining two beams 8B inclined relative to the horizontal plane. The frame of the house can be ensured.

 As shown in this figure 3, one can equip such a structure with a roof. Corrugated sheets 12 in light structure, for example, in polyester, can constitute the elements of this cover. The corrugations of the corrugated sheets 12 must correspond to the spacing of the tubes 9 ensuring the frame of such a house. The sheets 12 can thus be positioned on said frame.

 Such a house can be completed by wall elements 13 in the form of more or less long panels and having on two opposite edges a semi-cylindrical recess of diameter corresponding to the outside diameter D of the tubes. Such a longitudinal recess 14 can therefore allow the fixing of the wall elements 13 between two tubes 9 and constitute a complete rllr of a house. Of course, windows can be provided as well as orifices. We can also provide for the use of panels of different colors.

 It is important to emphasize that the tubes 9 and the wall elements 13 are preferably rotomolded like the beams 8, 8A and 8B since these elements are hollow.

The surface condition of all these elements is similar and the colors are obtained at the manufacturer's discretion when filling the mold with various dyes.

 The unused holes 3 of the beams 8 may preferably be plugged by means of plugs 15 of different colors or identical to the color of the beams. A different color and in contrast to that of the beams can increase the variegated and attractive effect of such a structure in a kindergarten.

 All these elements are obtained from polymer, preferably polyethylenes.

 It should be noted that rotational molding makes it very easy to make all rounded shapes, which can provide certain security for children who have to climb on structures made up of such rotomolded elements, thus avoiding abrasions or cuts due to sharp edges.

 The example in Figure 4 is a ring. It is in fact made up of four vertical sections of beams 16 each assembled to an adjacent section by means of two to four horizontal tubes 17. The assembly is identical to that carried out on the house structure of FIG. 3.

Plugs 15 can complete such a ring. Such a structure can also be completed with an elastic mat 18 placed horizontally in the middle of the four beam sections 16 to form a trampoline. One can obviously imagine any attraction inside such a ring structure.

 Another possible embodiment with rotomolded elements is illustrated in Figure 5. It is a swing. Such a game can be achieved by means of a base, that is to say of a stable support 19 fixed on the ground, preferably made of rotomolded polymer. This stable support 19 has an upper end in the form of a yoke, or has a recess 20 in the form of a trench.

In addition, it has through the two walls of this recess 20 or the yoke a horizontal hole in which is fixed a section of tubes 21. A beam 8 is placed in the recess 20 so that the section of tube 21 passes through one of these holes 3. This beam 8 is thus placed in rotation about a horizontal axis, in this case that of the tube 21. If this axis is placed at a height between fifty centimeters and one meter twenty, a traditional swing is quickly assembled.

 Another feasible structure for a kindergarten is shown in Figure 6. It is an American swing. A horizontal beam 22 on which one or more people take place is kept horizontal in the middle of a pendulum made up of two uprights placed at the ends of the beam 22.

These uprights each consist of two vertical beams 23 linked together by several tubes 24.

These uprights are pivotally mounted each around a different horizontal axis, in this case that of a horizontal rocking tube. The latter can be mounted fixed by two main gantries 26 each consisting of at least two beams assembled in a vee by means of a reinforcement bar 27 at the top and one or more spacer tubes 28.

 With reference to FIGS. 7A, 7B and 7C, the fixing of the tubes 9 to the beams 8 can be ensured by means of a nail. The latter then serves as a fixing pin.

 it can be rotomolded polyethylene.

 As shown in FIG. 7A, the nail 30 can pass through the two external walls and the two internal walls of the beam 8 which is therefore crossed by a hole intended to place the tube 9. The nail 30 also passing through the tube 9, this one it rests on six surfaces it crosses.

 FIG. 7B shows a similar nail 31 but of a reduced length so as not to open into one of the external surfaces of the beam 8. In this case, this nail 31 passes through five walls.

 FIG. 7C shows a nail 32 which does not lead to any of the two external walls of the beam 8. In this case, it rests on four walls which it crosses, in this case two of the beam 8 and two of the tube 9 In this case, it ensures minimal fixation.

 In all these cases, the nail can of course have a head 33. In the last case, the nail 32 can be completed with a plug 34 covering a hole 35 essential for the introduction of the nail 32.

 Such a nail then has semi-rigid walls and can be force-fitted by means of a hammer into the holes 3 of the beams 8 and into the tubes 9.

 Such a nail can also be made of plastic, by blowing.

 Apart from the sides and the reinforcements, all these elements are also rotomolded and can be assembled à la carte by the users or the designers of the attraction. Other elements can be designed from rotomolded polymer parts, as soon as they are hollow parts which must be light and of low cost.

 We cite a coffee table to serve as a picnic table consisting mainly of a hollow horizontal tray in the lower flat face of which there are four cavities which allow to place four hollow cubes each constituting themselves a foot of the table.

 I1 is also possible, as shown in Figure 4 to build with several adjacent sides of the ring a continuous barrier to form an enclosure. It is also possible to constitute obstacles for a horse racing course using sections of vertical beam and cylinders placed at the desired heights to constitute the adequate obstacle.

 Figure 3 suggests building a house. The modular nature of the various elements of which it is made possible to envisage the construction of temporary buildings, modular or not, to constitute the framework or the complete structure of a shelter, an exhibition hall, a shed , or any building with more or less temporary use.

 It is also possible to provide for the manufacture by rotational molding of mechanical elements, such as wheels which can be assembled two by two with a section of tube to constitute an axle. It is thus possible to build carriages in which the very short wagons of a train running on rotomolded rails. Indeed, these can consist of beams which have been discussed so far, tubes which can act as crosspieces. Two or three wagons placed on rails of several tens of meters can be an attractive attraction in the context of the development of a leisure park for children.

 In general, rotational molding allows the production of bulky, hollow, light objects, closed or not. It is therefore easily understood that the method and the system according to the invention consisting in using several different rotomolded elements of human size to constitute light structures, themselves of human size, can have very diverse applications, both in the context of leisure, outdoor, landscaping, or exhibition activity only in an industrial setting, for example to constitute definitive shelter or storage material.

 These few exemplary embodiments are of course not limiting. They constitute the first structures produced by the depositor in the context of the manufacture of the first elements of; system according to the invention, namely, tubes, beams, wall elements. Many other elements can be designed by rotational molding of polymers and enter into the constitution of structures constructed according to the method of the present invention.

 Any arrangement for an already existing rotomoulded element can be implemented. The rotomolded plugs 15 of FIG. 3 have already been described. Mention may also be made of a lining of rotomolded tubes, itself made up of a split tube, but the internal diameter of which roughly corresponds to the external diameter of the tube to be protected. Such a lining can also constitute a reinforcement or a mounting spacer in a mobile structure, such as the American swing.

Claims (10)

 1. A method of building light structures, on a human scale, characterized in that it consists in assembling different polymer elements, light, rotomolded, hollow and having complementary shapes in order to be able to assemble with each other and form said structure .  2. Construction system of light structures, of human size, characterized in that it consists in assembling different polymer elements, light, rotomolded, hollow, having complementary shapes to be able to assemble to each other and form a structure , said elements being  - beams (8, 8A, 8B, 10, 16, 22, 23, 26) in which appear circular holes (3) of determined diameter (D); and  - Tubes (9, 17, 21, 24, 28) of external diameter corresponding to the diameter (D) of the holes (3) of the beams, so that they can be inserted inside these holes (3).  3. System according to claim 2, characterized in that it comprises wall elements (13) in the form of panels of which at least two opposite parallel sections have a longitudinal recess (14) complementary to the external diameter of the tubes (9) in order to be able to constitute sections of walls on a structure itself made up of several parallel tubes (9).  4. System according to claim 2 or 3, characterized in that it comprises plugs (15) in rotomolded polymer to plug the unused holes (3) of the beams (8, 16).  5. System according to any one of claims 2 to 4, characterized in that it comprises corrugated sheets (12) of polyester to constitute the cover of a structure in the form of a frame composed of at least two parallel beams ( 10) connected by several tubes (9) and on which the sheets (14) are supported by one side of the corrugated sheet of shape complementary to the tubes (9) to be positioned relative to them.  6. System according to claim 2, characterized in that it comprises to constitute a table  - a rotomolded polymer panel having a flat surface usable as a table and an opposite surface provided with foot holes; and  - feet in rotomolded polymer having a section complementary to the hole in the panel to constitute the feet of said table.  7. System according to claim 2, intended to constitute a swing, characterized in that it consists of a stable support (19) of rotomolded polymer constituting a yoke and having a horizontal hole which can receive a section of tube (21) around which a beam (8) can be pivotally mounted.  8. System according to any one of claims 2 to 5, characterized in that it includes fishplates (10, 11, 27) for fixing two juxtaposed beams and angularly offset relative to each other (8A, 8B, 26) to ensure the maintenance of these two beams.  9. System according to claim 2, characterized in that it comprises longitudinal reinforcements (7) placed inside the beams (8) to strengthen them and thus stiffen the constructed structure.  10. System according to claim 2, characterized in that it comprises nails (30, 31, 32) intended to secure the tubes (9, 17, 21, 24, 28) in the beams (8, 8A, 8B, 10, 16, 23, 26).