Paving Stones, Method for Laying Pavement with Same and Method for Producing Same

Abstract

The invention relates to a set of paving stones having different thicknesses with respect to each other. At least one oblong recess is provided in the bottom side of each of the paving stones of the set, said oblong recess extending from one lateral side of the stone up to another lateral side, having a continuous cross-section and being provided for accommodating a complementary, regularly shaped carrier onto which the paving stones are to be laid. For each paving stone the/each recess extends into the bottom side of the paving stone up to a predetermined first distance (h) from a tangent plane to the top side, said predetermined first distance (h) being substantially the same for all paving stones of the set. The invention further relates to a method for laying a pavement with these paving stones and a method for producing these paving stones.

Description

TECHNICAL FIELD

The present invention relates to a set of paving stones, a method for laying a pavement with these paving stones and a method for producing these paving stones.

BACKGROUND ART

Natural hewn stones, such as for example cobblestones and the like, have irregular, rough surfaces as a result of the fact that they were hewn out of rocks in quarries. The dimensions of the stones are also not uniform. As a result of these irregular features, the laying of pavements with these stones involves more skill than just placing the stones on the sand bed or foundation bed as is the case with paving stones of uniform dimensions and more even surfaces such as for example cut tiles, concrete tiles or paving stones, brick stones or other stones with fixed dimensions. Upon laying a pavement with natural hewn stones, the worker has to take the variations in thickness and the unevenness of the surfaces into account (see FIG. 1), since it is desired that the top surface of the pavement is as flat as possible. As a result, laying a pavement with natural hewn stones or irregularly shaped paving stones is a time consuming operation which requires a high degree of craftsmanship.

More in general, similar problems could arise with “regular” paving stones which are produced with too much tolerance, i.e. too much deviations in the dimensions of one stone with respect to another.

A solution could be to unite the paving stones to a larger prefabricated plate of a uniform size, such as for example described in DE-A-19801378. This however has the disadvantage that larger plates of paving stones have to be treated upon laying the pavement, which may be too large and too heavy to manipulate by hand, so that machinery is necessary. Furthermore, such methods are bound to a limited number of stone types, colours and sizes and the size of the plate is fixed, all of which limits the flexibility of application and the possibility to choose and vary stones in the pavement.

DISCLOSURE OF THE INVENTION

It is an aim of the present invention to provide paving stones with which a pavement can be constructed more quickly without necessitating the use of machinery or special tools like a mallet or such.

This aim is achieved according to the invention with the set of paving stones showing the technical features of claim 1.

It is also an aim of the present invention to provide a method for laying a pavement in which the paving stones are still placed one by one but at a higher pace.

This aim is achieved according to the invention with the method comprising the steps of claim 7.

It is furthermore an aim of the present invention to provide a cost-efficient method for producing the paving stones of the invention.

This aim achieved according to the invention with the method comprising the steps of claim 15.

As used herein, a “pavement” is intended to mean the durable surface of roads, walkways, driveways, terraces etc.

Each stone of a set of paving stones according to the invention has a top side, a bottom side and a plurality of lateral sides which extend from the top side to the bottom side. The top, bottom and lateral sides may each have an even or an uneven surface. The thickness of the stones, measured between parallel tangent planes to the top side and the bottom side, differs to a given extent from one stone to the other, i.e. the stones do not have a uniform thickness. According to the invention, at least one oblong recess is provided in the bottom side of each of the paving stones. This recess extends from one lateral side of the stone to another and has a continuous cross-section, so that it is adapted for accommodating a complementary, regularly shaped carrier onto which the paving stones are to be laid on top of the foundation bed. For each paving stone, each oblong recess extends into the bottom side of the stone up to a first distance from the tangent plane to the top side. This first distance is a predetermined distance which is the same for all paving stones of the set.

In laying a pavement with the paving stones of the invention, carriers, shaped complementary to the oblong recesses in the bottom side of the paving stones, are first placed on top of an evened-out foundation bed, after which the paving stones are placed on top of the carriers. As a result of the predetermined distance between the top of each recess and the tangent plane to the top side of the stone, which distance is uniform for all of the stones, the tangent planes to the top sides of all the stones end up in substantially the same plane. Usually, though not essentially, the pavement will be finished by compacting it by means of a compacting device and by filling the joints by means of a suitable filler material.

As a result of the use of the carrier and the complementary recesses in the bottom side of the stones, differences in thickness of the stones do no longer have to be taken into account upon laying each stone by pressing it more or less into the foundation bed, as it is done up to now. As a result, less skilled workers can lay a pavement with the paving stones of the invention. For example, in the case of natural stone pavements, the laying is no longer the privilege of a limited number of craftsmen. This is advantageous, since the craftsmanship of laying for example a cobblestone pavement is no longer passed on from father to son as much as in earlier days, so the number of skilled craftsmen is ever reducing.

With the stones of the invention, whether they are natural stones or man-made stones, pavements can now be laid by less skilled workers without affecting the quality of the end result since differences in thickness are still overcome without requiring the workers to locally adapt the height of the foundation bed to the thickness of the stone. In fact, the quality of the end result may even be enhanced, since the carriers which engage in the recesses of the stones function as additional stabilisers for the stones.

Furthermore, with the paving stones of the invention, a pavement can be laid at a higher pace with respect to the prior art. Up to now, the skilled worker had to adjust the position of each stone individually directly after it was laid on the foundation bed by tapping it by mallet into the foundation bed to a given extent to overcome the thickness and by repositioning the stone until the joint with the adjacent stones was acceptable, etc. With the paving stones of the invention, the variations in thickness are already overcome once the stone is laid and the joint can also immediately be fixed by the carrier, so that the pavement laying pace can be highly enhanced, also because the worker now has both hands available for laying stones. This limits the duration of road blocks and other inconveniences in cities and municipalities, especially since a pavement laid with stones according to the invention is immediately stabilised by the carriers, so that people can be allowed to walk over the newly laid pavement before it is finally finished by compacting and filling the joints.

The fact that the recess in the bottom side of the stone is an oblong recess extending from one lateral side up to another lateral side has the advantage that oblong carriers can be used which support multiple stones and thus further stabilise the pavement, and that there is still a degree of freedom in the axial direction of the recess so that stones of different lengths (in axial direction of the recess) can be laid randomly and that the width of the joints on either end of the recess can be adapted at will, since the stones can be moved in axial direction of the recesses along the carriers until the optimal position is reached. So the use of the carriers does also not put a bar on the creativity.

In a preferred embodiment of the invention, the paving stones are generally parallelepiped-shaped, meaning that they have two pairs of substantially parallel lateral sides which are substantially perpendicular to the top and bottom sides. In this embodiment, preferably two recesses are provided in the bottom side of each stone along one of said pairs of lateral sides of the stone. These two recesses are preferably spaced a predetermined second distance from each other, which is again substantially the same for all paving stones of the set. With this embodiment, oblong carriers are used which define rows or columns of paving stones of the pavement, which can simplify the laying of the pavement and thus can further enhance the pace at which the pavement can be laid. The worker can now simply place the carriers for a new row at the second distance from the carriers supporting the previous row of paving stones and then place the paving stones on top of the carriers.

Preferably the two recesses are open towards the lateral sides of the stones, so that each carrier can be used for supporting two adjacent paving stones. Preferably a central portion of the bottom side of the stone which is delimited by the two recesses is on average about in the middle of the stone. This means that the lateral sides of the paving stones protrude substantially always the same distance over the carriers. This can substantially fix the width of the joints between adjacent rows of paving stones, thus avoiding irregularities and thus instabilities in the pavement.

Preferably, each of the recesses in the stone comprises a top side substantially parallel to the tangent plane to the top side of the stone and a lateral side substantially perpendicular to said top side. More preferably, each of the recesses is adapted for accommodating a parallelepiped-shaped carrier. This enables the use of carriers with a rectangular cross-section such as for example wooden beams, which are widely available and thus cheap. However, this does not preclude the use of other carriers in other materials and with other shapes, such as for example carriers made of metal, stone, a plastic material or for example a recycled plastic and having triangular, trapezoidal, semi-circular, circular, stepped or other cross-sections.

The paving stones of the invention can for example be natural hewn stones, such as for example cobblestones, of which most or all sides have uneven surfaces, or any other natural or man-made paving stones known to the person skilled in the art. The invention can for example also be applied for mixing different types of stones with each other, i.e. for example for laying pavements which partly comprise natural stones and partly comprise man-made stones.

The method for laying a pavement according to the invention makes use of one of the above described embodiments of paving stones. The method for laying a pavement comprises the following steps. First, a foundation bed is evened out. Next, regularly shaped carriers are placed on the foundation bed, each of said carriers being complementary to the recesses in the bottom sides of the paving stones. Then, the paving stones are placed on the carriers, such that the carriers engage in the recesses and the tangent planes of the top sides of the paving stones are located substantially in the same plane.

The advantages of the method for laying a pavement of the invention have already been described above and will therefore not be repeated here.

The carriers are preferably placed at about a predetermined third distance from each other which corresponds to the distance between two successive recesses in the bottom side of one stone or in the bottom sides of two successive rows of stones, depending on the paving stones which are used.

Preferably most of the carriers have lengths which span multiple paving stones, so that they support two or more paving stones. This can further enhance the stability of the pavement.

The carriers can for example be laid in rows or columns, or in bows, circles or in a fan-shaped pattern, or according to any other pattern known to the person skilled in the art, depending on the desired pattern for the pavement or the general shape of the paving stones.

The carriers are preferably parallelepiped-shaped with a rectangular cross-section, but any other geometrical shapes are also possible, such as for example triangular, trapezoidal, semi-circular, circular, stepped or other cross-sections. In an embodiment according to the invention, the carriers have wider sides and narrower sides and are placed on the foundation bed by means of one of the wider sides. The carriers may also be placed on one of the narrower sides, which may for example be useful on a side of the pavement against a wall.

In a preferred embodiment of the method for laying a pavement according to the invention, the carriers are placed in fixed relationship with respect to each other by means of fixing means, according to a predetermined pattern in which the paving stones are to be laid. The fixing means can for example be formed by screws or nails which anchor the carriers to a foundation or to each other. This embodiment can further enhance the stability of the pavement.

The method for laying a pavement according to the invention may further comprise at least one of the following steps: compacting the pavement by means of a compacting device and/or filling joints in between the paving stones of the pavement by means of a filling material. These steps are known in the art and need no further explanation.

The method for producing the stones according to the invention preferably comprises the step of creating the recesses by cutting or milling material from the bottom side of each stone. This is a quick and thus advantageous way to create the recesses. This way of creating the recesses can conveniently be automated, so that the paving stones of the invention can be produced on an assembly line. For example, the stones can be placed upside down on a conveyor belt and pass through a cutting/milling machine for creating the recesses. This is convenient since the conveyor belt then corresponds to the tangent plane to the top side of the stones.

In a preferred embodiment of the method of the invention, two recesses are created in the bottom side along one pair of lateral sides of the stone and two further recesses are created in the top side of each stone, along the same pair of lateral sides as where the recesses at the bottom side are located. Then, each stone is divided up into two parts generally along a plane parallel or perpendicular to said tangent plane to the top side of the stone. In this way, two paving stones can be constructed from one block of stone.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be further elucidated by means of the following description and the appended figures.

FIG. 1 shows a plurality of prior art paving stones.

FIG. 2 shows how paving stones are adapted according to an embodiment of the invention.

FIGS. 3 and 4 show how a pavement is laid according to an embodiment of the invention.

MODES FOR CARRYING OUT THE INVENTION

The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes. The dimensions and the relative dimensions do not necessarily correspond to actual reductions to practice of the invention.

Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. The terms are interchangeable under appropriate circumstances and the embodiments of the invention can operate in other sequences than described or illustrated herein.

Moreover, the terms top, bottom, over, under and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. The terms so used are interchangeable under appropriate circumstances and the embodiments of the invention described herein can operate in other orientations than described or illustrated herein.

The term “comprising”, used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It needs to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression “a device comprising means A and B” should not be limited to devices consisting only of components A and B. It means that with respect to the present invention, the only relevant components of the device are A and B.

The problem underlying the invention is clarified by means of FIG. 1. A number of natural paving stones 1, 2, 3, 4 of generally parallelepiped shape with hewn surfaces are shown, with their top sides substantially in the same plane. As shown, the thickness H of these stones, which is measured between a tangent plane to the top side and a parallel tangent plane to the bottom side, varies from one stone to another to a large extent. The dimensions of the stones 1, 2, 3, 4 are also not uniform. As a result of these irregular features, the laying of pavements with these stones involves more skill than just placing the stones on the sand bed or foundation bed as is the case with paving stones of uniform dimensions and more even surfaces such as for example cut tiles, concrete tiles or paving stones, brick stones or other stones with fixed dimensions. Upon laying a pavement with these natural hewn stones, the worker has to take the variations in thickness H and the unevenness of the surfaces into account, since it is desired that the top surface of the pavement is as flat as possible. As a result, laying a pavement with these natural hewn stones 1, 2, 3, 4 is a time consuming operation which requires a high degree of craftsmanship.

FIG. 2 shows how this problem is tackled according to the invention. On the left, an irregularly shaped paving stone 5 is shown before treatment and on the right, an irregularly shaped paving stone 6 is shown after treatment according to the invention. The thickness H of the stone 6 has been laterally reduced to a thickness h by cutting recesses 7, 8 of average height h1 into the bottom side 9 of the stone 6. The top sides 11, 12 of the recesses 7, 8 are parallel to the tangent plane to the top side 10 of the stone 6, so that the reduced thickness h is substantially constant over the full length of the stone.

The recesses 7, 8 furthermore have an average width b1 and define a central portion 15 on the bottom side 9 of the stone 6 which is delimited by their lateral sides 13, 14. The width b1 of the recesses 7, 8 is chosen such that variations in the width B of the stone are fully taken up by the recesses 7, 8, so that the reduced width b also becomes a substantially constant value over the full length of the stone. Since the recesses 7, 8 of substantially the same width b1 extend on either side of the central portion 15 of the bottom side of the stone, the central portion 15 is centred.

It can thus be stated that H=h+h1 and B=b1+b+b1. The result of the recesses 7, 8 is that from stones 5 with large variations in thickness H and width B, stones 6 are produced with a constant reduced thickness h and a constant and centred reduced width b.

With treated paving stones 6, a pavement is now laid as shown by means of FIGS. 3 and 4. A foundation bed 16 is evened out, which may for example comprise sand, a mixture of sand and cement, concrete or any other foundation bed known to the person skilled in the art. Then, carriers 17 are placed on the foundation bed 16 at regular distances from each other, such that the central portions 15 of the bottom sides 9 of the stones 6 can be accommodated between them. Afterwards, the stones 6 are placed on the carriers 17, such that the carriers 17 engage in the recesses 7, 8 and the top sides 10 of the stones 6 become located in substantially the same plane. In this way, the pavement can be laid quickly by relatively less skilled workers, since irregularities in the dimensions of the stones are immediately overcome and there is no longer a need to locally adapt the foundation bed.

The carriers 17 have a rectangular cross-section with dimensions E×h2, preferably E being greater than 2×b1 and h2 being greater than h1, so that the variations in the dimensions of the stones 6 are fully taken up by the carriers 17, leading to joints 18 of average width e between the stones 6.

The stones 6 are supported both vertically and horizontally, since the lateral sides 13, 14 of the recesses 7, 8 lie against the carriers 17. As a result, rotations or displacements of the stones 6 are prevented.

The carriers 17 can be laid in rows or columns, or in bows, circles or in a fan-shaped pattern, or according to any other pattern known to the person skilled in the art, depending on the desired pattern for the pavement or the general shape of the paving stones.

Optionally, though not necessarily, the resulting pavement can be finished by compacting it by means of a compacting device and by filling the joints by means of a suitable filler material. It can for example be advantageous to leave the joints between the stones open for evacuation of rain water, or to have a floating pavement of which the stones themselves do not rest on the foundation bed.

Optionally, though not necessarily, the carriers 17 may be anchored to the foundation bed 16 or otherwise brought in fixed relationship with each other before laying the stones 6 on top of them.

The paving stones 6 shown in FIGS. 2-4 are generally parallelepiped-shaped. However, other shapes are also possible. The recesses 7, 8 have perpendicular sides 11, 12, 13, 14 so that they are adapted for accommodating parallelepiped-shaped carriers 17, but they may also be shaped for accommodating carriers with triangular, trapezoidal, semi-circular, circular, stepped or other cross-sections. The paving stones 6 are natural stones with hewn surfaces, but the invention may also be applied to paving stones with even surfaces and/or more regular dimensions, such as for example concrete tiles etc. of which the variation of the dimensions is unsuitably large.

The paving stones 6 shown in FIGS. 2-4 have a recess 7, 8 on either side of the bottom side 9. Alternatively, a single oblong recess preferably substantially in the middle of the bottom side may also be used, or multiple recesses, not necessarily on the lateral sides of the stones 6. Recesses may furthermore be applied in directions which cross each other.

The carriers 17 may be constructed in wood, stone, metal, a plastic material or any other material known to the person skilled in the art. Preferably, carriers in recycled plastics are used for ecological reasons.

Claims

1. A set of paving stones, each having a top side, a bottom side and a plurality of lateral sides extending from the top side to the bottom side, the paving stones having different thicknesses which vary to a large extent with respect to each other, the thickness of each stone being measured between parallel tangent planes to the top and bottom sides of the stone, wherein at least one oblong recess is provided in the bottom side of each of the paving stones of the set, said oblong recess extending from one lateral side of the stone up to another lateral side, having a continuous cross-section and being provided for accommodating a complementary, regularly shaped carrier onto which the paving stones are to be laid, and wherein for each paving stone the/each recess extends into the bottom side of the paving stone up to a predetermined first distance (h) from a tangent plane to the top side, said predetermined first distance (h) being substantially the same for all paving stones of the set and being provided for overcoming the differences in thickness.

2. A set of paving stones according to claim 1, wherein each stone is generally parallelepiped-shaped with two pairs of substantially parallel lateral sides extending from the top side to the bottom side, two of said recesses being provided in the bottom side of each stone along one of said pairs of lateral sides of the stone, said two recesses being spaced a predetermined second distance (b) from each other, said predetermined second distance (b) being substantially the same for all paving stones of the set.

3. A set of paving stones according to claim 2, wherein said two recesses are open towards the lateral sides and wherein a central portion of the bottom side of the stone delimited by the two recesses is on average about in the middle of the stone.

4. A set of paving stones according to claim 1, wherein each of said recesses comprises a top side substantially parallel to said tangent plane to the top side of the stone and a lateral side substantially perpendicular to said top side.

5. A set of paving stones according claim 1, wherein each of said recesses is adapted for accommodating a parallelepiped-shaped carrier.

6. A set of paving stones according to any claim 1, wherein the stones are natural hewn stones of which at least one of the sides has an uneven surface.

7. Method for laying a pavement by means of paving stones according to claim 1, the method comprising the step of:

a) evening out a foundation bed,

wherein the method further comprises the steps of:

b) placing oblong carriers on the foundation bed, each of said oblong carriers being regularly shaped and being complementary to the recesses which are provided in the bottom sides of the paving stones,

c) placing the paving stones on the carriers, such that the carriers engage in the recesses and the tangent planes of the top sides of the paving stones are located substantially in the same plane.

8. Method for laying a pavement according to claim 7, wherein in step b) the carriers are placed at about a predetermined third distance (b) from each other, said third distance (b) corresponding to the distance between two successive recesses in the bottom sides of the stones.

9. Method for laying a pavement according to claim 7, wherein most of the carriers have lengths which span multiple paving stones.

10. Method for laying a pavement according to claim 7, wherein the carriers are laid in rows, bows, circles or in a fan-shaped pattern.

11. Method for laying a pavement according to claim 7, wherein the carriers are parallelepiped-shaped.

12. Method for laying a pavement according to claim 11, wherein the carriers have wider sides and narrower sides, the carriers being placed on the foundation bed by means of one of the wider sides.

13. Method for laying a pavement according to claim 7, wherein the carriers are placed in fixed relationship with each other by means of fixing means according to a predetermined pattern in which the paving stones are to be laid.

14. Method for laying a pavement according to claim 7, wherein the method further comprises at least one of the following steps:

d) compacting the pavement by means of a compacting device,

e) filling joints in between the paving stones of the pavement by means of a filling material.

15. Method for producing paving stones according to claim 1, wherein the recesses are created by cutting or milling material from the bottom side of each stone.

16. Method for producing irregularly shaped paving stones according to claim 15, wherein the paving stones are generally parallelepiped-shaped with two pairs of substantially parallel lateral sides extending from the top side to the bottom side, and two of said recesses are created in the bottom side of each stone along one of said pairs of lateral sides, and wherein the method further comprises the steps of creating two further recesses in the top surface of each stone along said one pair of lateral sides, and dividing the stone up into two parts substantially along a plane parallel or perpendicular to said tangent plane to the top side of the stone.