Panel and Use of Such a Panel As A Scaffolding Board or a Building Panel

- Makers B.V.

The present invention relates to a panel comprising two parallel skin plates made of wood or a wood material, between which ribs extend for stiffening the panel, wherein the ribs are at least substantially made of wood or a wood material. The present invention further relates to the use of such a panel as a scaffolding board or a construction element and to scaffolding provided with such panels.

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Description
CLAIM OF PRIORITY

This application is a continuation-in-part of U.S. patent application Ser. No. 12/247,607 filed Oct. 8, 2008, which claims priority to PCT/NL2007/000098 filed Apr. 12, 2007, the National Stage of International Application No. PCT/NL2007/000098 filed Apr. 12, 2007.

FIELD OF THE INVENTION

The present invention relates to a panel comprising two parallel skin plates made of wood or a wood material, between which ribs extend for stiffening the panel.

DESCRIPTION OF RELATED ART

Such panels are known, they are used inter alia for doors in houses. The skin plates are made of plywood and form the outer sides of the door. Present between the skin plates is a honeycomb structure of cardboard, which functions to stiffen the door. Such a panel is in itself suitable for use with a door that separates two internal spaces of a building from each other, but it is less suitable for taking up comparatively large forces. Thicker skin plates, and in some cases even solid wood, are used for relatively heavy applications. In the case of doors, the skin plates are provided on a framework. In some cases the framework comprises cross slats, which extend between circumferential edges of the framework. Said cross slats are not regarded as ribs in the present document. Ribs can be distinguished from the framework in that they are made of a different material and/or have a different thickness or other properties.

these prior art laminated panels do not provide the necessary stiffness for many applications for which an improved panel might find use, and accordingly, an improved panel is believed to be necessary.

SUMMARY OF THE INVENTION

Consequently it is an object of the present invention to provide a panel as referred to in the introduction which is also suitable for heavier applications, without thicker skin plates or skin plates of a stronger type of wood being absolutely required. This object is achieved by the present invention In that the ribs are at least substantially made of wood or a wood material. By making the ribs of a material which is more rigid than the cardboard that has been used so far for the ribs, the ribs are capable of taking up larger forces and it is possible to use the panel for heavier applications, in other words, for taking up greater loads, and thus take up heavier loads with a panel according to the invention while using comparable skin plates. On the other hand it is possible to use less strong skin plates in comparison with the known skin plates used in the panels according to the prior art for taking up comparable forces, because the ribs will compensate the reduced strength. With a number of applications it is even possible to use a panel according to the present invention instead of a solid plank.

In a preferred embodiment of the invention, the wood material comprises multi-ply or fibreboard. These materials make it possible to manufacture comparatively strong skin plates from comparatively low-grade wood. Furthermore, fibreboard such as MDF or chipboard is a material into which wood waste can be incorporated, so that such materials can be regarded as environmentally friendly. The use of these wood materials relates both to the wood material for the skin plates and to the wood material for the ribs.

In a preferred embodiment of the invention, the ribs are strip-shaped and extend crosswise from one of the two skin plates to the other skin plate, but for at least some embodiments, not into one or either of the skin plates. Strip-shaped ribs may simply be made of board materials and can thus be produced separately from the skin plates, so that panels can be assembled as desired at a relatively late stage.

In a preferred embodiment, at least some of the ribs extend parallel to each other in their longitudinal direction. This leads to a uniform distribution of the strength of the panel.

In a preferred embodiment of the invention. the spacing between two adjacent ribs extending parallel to each other ranges between 1 and 10 cm. This makes it possible to provide panels which on the one hand have sufficient/strength and which on the other hand are comparatively light in weight.

Preferably, the ribs are arranged in a diamond-shaped and/or a rectangular pattern. Such patterns further contribute to a uniform distribution of the strength, or rigidity, of the panel.

In a preferred embodiment of the invention, intersecting ribs are each provided with a notch at the location of their points of intersection, with their notches engaging one another. In this way a diamond-shaped or a rectangular pattern can be readily formed whilst ensuring that the two sides of the strips make contact with the respective skin plates of the panel, for many embodiments without extending into either of the two skin plates. In addition, a kind of harmonica effect can be realized in this manner, so that the shape of the system of ribs can be adapted to a certain extent before the ribs are provided between the skin plates.

The ribs preferably have a thickness of 0.5 to 2 mm. In this way the ribs provide sufficient rigidly, whilst on the other hand the weight of a panel according to the invention remains within bounds.

The ribs preferably have a width of 20 to 70 mm. The thickness of a panel is to a large extent determined by the width of the ribs and this, too, makes it possible to realize a wide range of panel thicknesses.

Preferably, the ribs are attached to the skin plates. As a result, the ribs are fixed in position with respect to the planar skin plates, thereby ensuring a uniform support of the skin plates by the ribs, preferably without the ribs extending into the skin plates.

In a preferred embodiment of the Invention, the ribs are glued to the skin plates, preferably by means of a construction glue, furthermore preferably by means of a water-resistant glue such as melamine glue. Gluing provides a strong connection between wood elements in a simple manner. Water-resistant melamine glue is impervious to moisture, so that the panels can also be used in moist environments.

In another preferred embodiment of the invention. a fibre mat, a glass fibre mat in a preferred embodiment, is provided between the ribs and the skin plates for stiffening purposes. Such fibre mats help to distribute the forces that are exerted on the skin plates over the ribs, so that a comparatively strong panel can be realized while using comparatively flexible materials for the skin plates.

In a preferred embodiment of the invention, the skin plates are provided on a framework. The framework may function both as a frame for defining the outer circumference of the panel and for contributing to the rigidity of the panel, in particular if part of the framework extends within the outer circumference of said frame, and thus of the panel.

The framework it is preferably made of wood. This reduces the number of materials that are used with such a panel.

In a preferred embodiment of the Invention, the ribs are spaced from the framework. Since the dimension of the ribs is smaller than the distance they must bridge between parts of the framework at the location in question, the ribs fit comparatively easily within the framework, which facilitates the assembly of the panel.

In a preferred embodiment of the invention, at least part of the panel has been treated with a water-repellent material. This makes it possible to use the panel in moist or even wet conditions, especially if a water-resistant glue is used in the case of the ribs being glued in place.

In a preferred embodiment of the invention, the panel has a length of at least 4 m and a width of at least 25 cm. Such a combination of dimensions renders the panel suitable for use as a bearing element In scaffolding, because of the advantageous stiffness/weight ratio of such a bearing element and because of the favorable ratio of length to width, which as such corresponds to that of conventional scaffolding planks. Especially an embodiment in which the skin plates are fixed to a framework having such dimensions, in which the ribs are moreover affixed to the skin plates by means of a water-resistant construction glue, and in which the panel has been treated with a water-repellent material, is quite suitable for use in scaffolding.

The present invention further relates to the use of a panel as described in the preceding paragraphs as a bearing element for use in scaffolding. Panels according to the present invention are very suitable for being used as substitutes for scaffolding planks. Scaffolding planks are traditionally made of solid wood, because they need to be strong (rigid) enough to support persons, tools and building materials, such as bricks, mortar and the like. A drawback of solid planks is that they are comparatively heavy. The increasingly stringent safety, health and welfare legislation imposes further and further limitations as regards the maximum load a worker is allowed to carry. Because of this. the scaffolding planks must be made lighter or be carried by two persons. Making the planks lighter can be realized by reducing their size, but this has a cost-increasing effect because more operations need to be carried out for covering a comparable area when smaller planks are used. Apart from said legislation. the current scaffolding planks are difficult to handle because the planks often need to be moved in vertical direction. Finally, falling scaffolding planks, a situation which unfortunately happens rather frequently, lead to dangerous situations, as such a heavy scaffolding plank may cause serious, in some cases even fatal injury when it hits a person.

A panel according to the present invention is intended for use as a bearing element for use in scaffolding, which bearing element is lighter than the traditionally used scaffolding planks and which moreover has the required constructional qualities. Depending on the selection of wood or wood material, the construction with the wooden ribs between the wooden skin plates on the one hand provides sufficient strength to meet the requirements made of a bearing element for use in scaffolding, whilst on the other hand a considerable saving in weight is achieved in comparison with scaffolding planks. Another advantage is that up to 70% less wood can be used in comparison with traditional scaffolding planks. If the embodiment of the panel that is used has been treated with a water-repellent material is used. the scaffolding board will certainly be resistant to precipitation. The embodiment comprising a fibre mat provides an even stronger scaffolding plank or makes it possible to realize an even greater saving on wood.

The present Invention further relates to scaffolding comprising a frame of interconnected standards and ledgers and wooden bearing elements supported on ledgers for supporting persons and/or building materials. Such scaffolding is known in the construction industry, they make use of bearing elements in the form of solid scaffolding planks. The drawback of using solid scaffolding planks has already been discussed In the foregoing, and consequently it is an object of the present invention to provide scaffolding in which the drawbacks of the use of solid scaffolding planks are at least partially overcome. This object is achieved by the present invention in that the bearing elements comprise panels according to the present invention. An important advantage of this is that the panels are easier to handle because of their comparatively low weight. A further advantage is that the overall construction of the scaffolding will be less heavy in comparison with traditional scaffolding that uses solid scaffolding planks as the bearing elements. In this way the risk of collapsing as a result of the frame being overloaded is significantly reduced, or a lighter frame can be used for constructing the scaffolding.

The present invention also relates to a method for constructing scaffolding, comprising the steps a) constructing a frame of interconnected standards and ledgers and b) placing wooden bearing elements on the ledgers. Such a method is generally known in the construction industry. Frequently a sublevel of the frame is constructed. after which bearing elements are provided, on which persons involved in the further erection of the scaffolding can subsequently position themselves. The solid scaffolding planks that have been used as bearing elements so far are comparatively heavy, and frequently the scaffolding planks are lifted by hand. As a result of the increasingly stringent safety, health and welfare legislation, equipment is sometimes used for lifting the scaffolding planks, or shorter scaffolding planks are used, so that the work can still be carried out by hand. In both cases, however, the efficiency with which the work is carried out is seriously diminished.

Consequently it is an object of the present invention to provide a method as described in the preceding paragraph wherein the efficiency of the method can be maintained or even improved whilst complying with more stringent safety, health and welfare legislation. This object is achieved by the present invention in that in step b) panels according to the present invention are placed on the ledgers as bearing elements. Step b) can be carried out after step a) has been completed, but in practice steps a) and b) are often carried out iteratively for increasing the height of scaffolding in steps. The advantage of using panels according to the present invention as bearing elements is that comparatively lightweight bearing elements are easier to handle than the scaffolding planks that have been used so far. As a result, the work involved in erecting scaffolding will be less heavy, whilst in addition comparatively large panels may be used without acting in violation of the health and safety laws.

The present invention further relates to the use of a panel according to the invention as a construction element. Many types and embodiments of construction elements are known. By using a panel according to the present invention, comparatively lightweight construction elements exhibiting a comparatively high degree of rigidity are provided, and comparatively low-grade wood types may be used, whilst a required rigidity of the construction element is nevertheless realized. Construction elements in the form of panels according to the invention may be used as substitutes for planks and other panels in various sectors, for example the construction industry and the furniture industry.

BRIEF DESCRIPTION OF DRAWINGS

The present invention will be explained in more detail below on the basis of a few preferred embodiments of the present invention. In the description, reference will be made to the appended drawings, in which:

FIGS. 1a is a cutaway plan view of a panel according to the present invention;

FIG. 1b is a cross-sectional view taken along the line A-A of FIG. 1a.

FIG. 2a schematically shows the manner in which the ribs of a preferred embodiment of the invention may be arranged relative to each other;

FIG. 2b is an exploded view of the skin plates and ribs of a panel according to the present invention; and

FIG. 2c is a perspective view of a panel according to the invention, in which a part of the upper skin plates has been left out for easy reference.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring to FIG. 1a, a plan view is shown of a panel 1 according to the present invention, whose upper skin plate and associated fibre mat have been left out in the drawing. The panel 1 comprises a wooden framework 2 of relatively thick slats, within which ribs made of MDF extend in the longitudinal direction and in the transverse direction of the panel 1. Between the ribs, the bottom side of the panel 1 can be distinguished, in this case a glass fibre mat 4 provided on a lower skin plate (not shown in FIG. 1a).

FIG. 1b shows a cross-sectional view of the panel 1 of FIG. 1a, along the line A-A, in which ribs 3 extending in the longitudinal direction are present between the wooden framework 2 and skin plates 5, which are provided with a fibre mat on the inner side of the panel.

FIGS. 2a, 2b and 2c show another embodiment according to the invention of a panel 11, in which ribs 13 extend between two skin plates 15, which ribs jointly form a pattern of squares.

Referring now to FIGS. 1a and 1b, a panel 1 is shown which is comparatively long and narrow and which is thus quite suitable for use as a scaffolding element. In FIG. 1a an upper skin plate 5 and the upper glass fibre mat 4 have been removed. thus providing a view of the interior of the panel for easy reference. A wooden framework 2 of planks or beams defines the outer circumference of the panel. As is shown in FIG. 1b, two skin plates 5 are provided on either side of the framework 2, and a glass fibre mat 4 is present on the inwardly facing sides of the skin plates 5. Said glass fibre mat 4 provides a more uniform distribution of forces on the MDF ribs 3 in the panel, especially when comparatively low-grade wood material is used for the skin plates 5. The MDF ribs 3 extend in the longitudinal direction and in the transverse direction, forming a grid for distributing the forces that are exerted on a skin plate 5, so that the panel will behave as a rigid panel. This is one of the aspects that contribute towards adapting the panel for use as a bearing element an scaffolding. Although the figures in this document are merely schematic figures, which are not drawn to scale, therefore, it may be assumed that the ribs 3 are significantly less thick than the framework 2. The framework may comprise a few cross connections, which extend between the two longitudinally extending planks or beams. Such a construction of panels is known in the prior art, but within the framework of the present invention such cross connections may be considered as components of the framework but by no means as ribs as referred to in the present invention.

FIGS. 2a, 2b and 2c show a panel, or at least a part thereof, which is shown in partial view and in exploded view in FIGS. 2a and 2b. FIG. 2a shows individual ribs 13, which are already oriented in the manner in which they are oriented in a panel, however, and the figures show that the ribs 13 are provided with equally spaced notches 16, via which the ribs are interlocked in a fixed orientation with respect to each other, in which crosswise, interlocked orientation the ribs are spaced a fixed distance apart.

FIG. 2b shows the ribs 13 of FIG. 2a in an interlocked position. As the figure shows, the mating ribs form a grid of squares, and the ribs extend the same distance at the upper side and at the bottom side (not shown), so that a good contact with planar surfaces of the skin plates 15 that are to be attached thereto is possible, preferably without extending into the skin plates 15 as shown. FIG. 2c finally shows a panel 11 in which the skin plates 15 and the ribs 13 are glued together with, for at least some embodiments, water repellent glue 17. With this element, too, a force that is locally applied to one skin plate 15 will be distributed over the ribs 13, so that the panel will behave as a rigid panel.

The above description and the figures are merely intended by way of explanation of the invention and must by no means be construed as being limitative to the scope of the invention, which is defined in the appended claims. Alternative embodiments and further aspects are possible without departing from the scope of the present invention. Panels according to the present invention are suitable for use as substitutes for, for example, solid wooden planks, for example if rigidity in the direction perpendicular to the plane of the planks is important and/or if the weight of a device in which the panels may be used is an important aspect. The environmental aspects may playa part as well in the consideration to substitute (solid) planks for panels according to the invention, since less wood is used in the panels according to the present invention than in the case of solid planks, and moreover lower-grade wood may be used for skin plates than has been the case so far as a result of the rigidity-enhancing effect of the wooden ribs. Possible uses of wooden panels and planks are generally known, which is why such uses of a panel according to the present invention, for example in the construction of scaffolding and in the furniture industry, have not been explained as such in the figures and the description. The use of panels according to the present invention in scaffolding application is only an example of the various possible applications of such panels since one can easily imagine that in scaffolding large forces will be applied on the panels, and that applications wherein smaller forces are expected to be applied are thus also possible.

A density of the product at various thicknesses of one embodiment has been found to be less than 300 kg/m3, such as for a 38 mm thickness, 263 kg/m3, a 50 mm thickness 221 kg/m3, a 80 mm thickness 170 kg/m3, and at 100 mm thicnness 153 kg/m3. This is on the order of balsa wood with significantly higher strength (The density of dry balsa wood ranges from 40-340 kg/m3 (2.5-21 lb/ft3), with a typical density of about 160 kg/m3 (10 lb/ft3)). Oak is 600-900 kg/m3, yellow pine is 420 kg/m3. Accordingly, the density is less than comparable solid wood alternatives typically used for structural panels.

On the other hand, MDF has a density of 750-800 kg/m3 and MDF typically weights 10-15% more (or has that percentage higher density) than particleboard of similar dimensions.

Deformation tests were taken of an exemplary embodiment in line with the standards of EN-310: 1993. Tests were performed at a required span of 1.0 m. Additionally, tests were performed using a span of 2.5 m (for comparison purposes). Results showed structural support for loads of at least 270 kg (595 lbs). Deflection of the panel at different thicknesses, is only a few millimeters at most (2.7 mm for a 270 kg load on the 38 mm embodiment, the deflection being less on the thicker embodiments, namely 50 mm, 80 mm and 100 mm (with it being less than 0.5 mm for the 80 and 100 mm embodiments).

The modulus of elasticity was calculated for each of the four embodiments. For 1 m boards, it ranged from about 3 to about 4.5 GPa, but not exceeding 5 GPa while at 2.5 m it ranged from 1.5 GPa to 4.5 GPa. These figures for similar thickness MDF are believed to be about three times higher than MDF (i.e., it deflects three times less than tested MDF under similar loading, MDF is around 1400-3100 N/mm2 for various grades). This is also believed to be comparable, but probably slightly less, than the modulus of elasticity of solid woods like white oak, red maple, and pine.

The thinnest product tested with 38 mm thickness when tested at 1 m×1 m panels has a rupture strength of 600 kg. A modulus of rupture is thus 6.62E6. This is lower than many comparable materials (like MDF 14-31 N/mm2), but high enough to use for structural applications.

The thickest product of 100 mm was tested and it did not break when 1500 kg was applied. A maximum estimated load of 3000 kg is estimated.

The panel of the preferred embodiment is believed to have rigidity comparable to solid wood products under load, and even improved over MDF whiles providing a huge weight advantage with an acceptable rupture (or strength) characteristics.

Prior art panels tested were too flexible to use as structural material, indicating that they had a modulus of elasticity greatly exceeding 5.0 GPa.

Claims

1. A panel comprising two parallel skin plates having perimeters made of a wood material substantially made of MDF, between which ribs extend in a width direction at least substantially a width between the skin plates for stiffening the panel without extending into the skin plates, characterized in that the ribs are at least substantially made of a wood material substantially made of MDF; wherein the ribs are planar strip-shaped slats and extend orthogonally crosswise from one of the two skin plates to but not into the other skin plate, said panel having a density of less than 300 kg/m3 and a modulus of elasticity not exceeding 5 GPa.

2. The panel according to claim 1, characterized in that at least some of the ribs extend parallel to each other in their a longitudinal direction, as defined in a direction perpendicular to the width.

3. The panel according to claim 2, characterized in that a spacing between two adjacent ribs extending parallel to each other ranges between 1 and 10 cm, and the panel has up to 70% less wood than the solid wood plank.

4. The panel according to claim 2 characterized in that the ribs are arranged in at least one of a diamond-shaped and a rectangular pattern in an interlocking manner with the ribs extending continuously in at least the longitudinal direction.

5. The panel according to claim 4, characterized in that the ribs intersect and are each provided with a respective notch located on each rib where the ribs intersect with the respective notches engaging one another internal to perimeters of the skin plates.

6. The panel according to claim 4, characterized in that the ribs have a thickness, defined in a direction perpendicular to the width, of 0.5 to 2 mm.

7. The panel according to claim 6, characterized in that the ribs have a width of 20 to 70 mm.

8. The panel according to claim 7, characterized in that the ribs are attached to the skin plates.

9. The panel according to claim 8, characterized in that the ribs are adhered to the skin plates.

10. The panel according to claim 1, characterized in that fibre mats are provided between the ribs and the skin plates in contact with the skin plates and adjacent to the ribs for stiffening purposes and the ribs connect directly to the fibre mats.

11. The panel according to claim 10, characterized in that said fibre mats are glass fibre mats.

12. The panel according to claim 6, characterized in that the skin plates are connected at and around their perimeters to a framework.

13. The panel according to claim 12, characterized in that the framework is made of wood.

14. The panel according to claim 12, characterized in that the ribs are spaced from the framework.

15. The panel according to claim 1, characterized in that at least a part of the panels is water-repellent and the ribs connect to the panel with a water repellent glue.

16. The panel according to claim 14, characterized in that the panel has a panel length, defined in a direction perpendicular to the width, of at least 4 m and a panel width, defined in a direction perpendicular to the width and the panel length, of at least 25 cm.

Patent History
Publication number: 20140302277
Type: Application
Filed: May 12, 2014
Publication Date: Oct 9, 2014
Applicant: Makers B.V. (Haarlem)
Inventors: Mark W. Van Der Horst (Haarlem), Diederick Van Der Horst (Twello)
Application Number: 14/275,294
Classifications
Current U.S. Class: Honeycomb-like (428/116); Including Sheet Or Component Perpendicular To Plane Of Web Or Sheet (428/119)
International Classification: E04C 2/14 (20060101); E04G 5/08 (20060101); E04C 2/36 (20060101);