Patent Application
20080205996
The present invention relates to a cellular honeycomb type reinforcing structure, and in particular, though not limited to such a reinforcing structure for use in the prevention of soil erosion, for example, coastal, river bank and lake shore erosion and the like, and the invention also relates to a method and apparatus for forming the cellular honeycomb type reinforcing structure. The invention also relates to a land erosion protective device, and the invention also relates to a method for preventing soil erosion.
There are many causes of soil erosion. For example, strong winds can cause soil erosion, whereby wind blowing over dry soil or sand can blow the soil or sand away. This is a particularly serious problem in the case of motorway embankments and sand dunes. Coastal and river erosion are also two primary causes of soil and land erosion, and indeed, many acres of land can be lost to the sea, rivers and lakes over relatively short periods of time.
Various reinforcing structures and methods have been utilised to minimize soil erosion, however, in general, known structures and methods suffer from various disadvantages. One method commonly used in the prevention of coastal erosion is to locate a plurality of wire mesh cages, typically of cuboid or parallelepiped construction which are filled with aggregate, typically, stones, shingles, rubble or other suitable rock armour material. The cages filled with aggregate are then deposited on the sea shore, and may be stacked one on top of the other, and indeed, in many cases, layers of such reinforcing cages are provided where one layer of cages is placed on top of the next layer, and so on. Such cages may be retained together by wire or steel reinforcing. However, it is not uncommon after a relatively serious storm to find such cages ruptured and scattered along the sea shore where they have been displaced and ruptured by waves.
Other methods for minimizing coastal erosion comprise the construction of breakwaters of mass reinforced concrete, or barriers which extend along the coastline of mass reinforced concrete. However, in general, with the passage of time and after being subjected to sufficient battering by storm waves, such breakwaters and barriers tend to be displaced and broken up by the constant pounding of waves. This problem is further exacerbated by virtue of the fact that in general, the constant pounding of waves on such barriers and indeed, on such breakwaters tend to undermine the foundations of the breakwaters and barriers, thereby facilitating relatively easy shifting of the barriers and breakwaters by storm waves.
There is therefore a need for a reinforcing structure which overcomes these problems of known erosion protection devices.
The present invention is directed towards providing such a reinforcing structure, and the invention is also directed towards providing a method and apparatus for constructing such a reinforcing structure, and further, the invention is directed towards providing a land erosion preventative device, and the invention is further directed towards providing a method for preventing soil erosion.
According to the invention there is provided a cellular honeycomb type reinforcing structure, wherein the reinforcing structure comprises a plurality of elongated sheets, each sheet being joined to its adjacent sheet on one side thereof at a plurality of first locations spaced apart along the length of the sheets, and to its adjacent sheet on the other side thereof at a plurality of second locations spaced apart along the length of the sheets, each second location being located intermediate an adjacent pair of first locations, the first locations of each pair of adjacent sheets defining unconnected portions extending therebetween where the sheets are unconnected, and the second locations of each pair of adjacent sheets defining unconnected portions extending therebetween where the sheets are unconnected, the cellular honeycomb type reinforcing structure being formed by urging the unconnected portions of adjacent sheets apart from each other for defining a matrix of cells.
In one embodiment of the invention the first and second locations alternate along the length of each sheet.
In another embodiment of the invention adjacent sheets at their respective first and second locations define retaining bores extending parallel to the planes of the sheets, and transversely of the length thereof.
In a further embodiment of the invention each sheet is of lattice structure material defining a plurality of openings therethrough, and being joined to its adjacent sheets at the respective first and second locations by inter-engaging portions of the sheet with corresponding openings in the adjacent sheets, and retaining the respective portions inter-engaged.
Preferably, the cells defined by urging the unconnected portions of adjacent sheets apart from each other are interconnected through the openings in the sheets.
Advantageously, the respective sheets are of regular lattice structure with the openings arranged in the form of a matrix.
In one embodiment of the invention each sheet is formed by a plurality of spaced apart longitudinal members and a plurality of spaced apart transverse members extending transversely of the longitudinal members and being joined to the longitudinal members, the longitudinal and transverse members defining the matrix of the openings. Preferably, the longitudinal members extend in a generally longitudinal direction along the length of each sheet. Advantageously, the longitudinal members extend parallel to each other, and the transverse members extend parallel to each other.
In a still further embodiment of the invention the inter-engaging portions of the adjacent sheets at the first and second locations define the retaining bores, and preferably, a retaining means is located in each retaining bore for retaining the portions inter-engaged. Preferably, each retaining means comprises an elongated retaining bar for engaging a corresponding one of the retaining bores. Advantageously, each retaining means comprises a receiving means.
In one embodiment of the invention securing means is provided for securing one of a top panel and a bottom panel to the reinforcing structure adjacent a corresponding one of a top and a bottom thereof.
In one embodiment of the invention a plurality of securing means are provided, and each securing means is adapted for engaging a corresponding one of the retaining bores or the receiving means for securing the one of the top panel and the bottom panel to the reinforcing structure. Preferably, each securing means is releasably securable to a corresponding one of the retaining bores or the receiving means. Advantageously, the receiving means of each retaining means comprises an axially extending receiving bore extending into the retaining means for receiving a corresponding one of the securing means.
In one embodiment of the invention each securing means comprises a spigot engageable with a corresponding one of the receiving bores of the retaining means. Advantageously, the spigot of each securing means terminates in a pan head for abutting and retaining the one of the top panel and the bottom panel in engagement with the reinforcing structure when the spigot is engaged in the receiving bore of the corresponding retaining means.
In one embodiment of the invention a pair of the receiving bores extends into each retaining means from respective axially opposite ends thereof for receiving corresponding ones of the securing means for securing the respective top and bottom panels to the reinforcing structure.
In another embodiment of the invention the top and bottom panels are of lattice type material defining a plurality of openings therethrough.
In a further embodiment of the invention each top and bottom panel is of regular lattice structure defining a matrix of openings. Preferably, each top and bottom panel is of a semi-rigid material. Advantageously, each top and bottom panel is of a plastics material.
In one embodiment of the invention each sheet forming the cellular reinforcing structure is of a semi-rigid material.
In another embodiment of the invention each sheet forming the cellular reinforcing structure is of a plastics material.
In an alternative embodiment of the invention the sheets are secured at each first and second location at a pair of spaced apart locations for defining the retaining bores.
In another embodiment of the invention the cells defined by urging the unconnected portions of adjacent sheets apart from each other are adapted for receiving in-fill.
In another embodiment of the invention the reinforcing structure is located on the ground for minimizing soil erosion, and the cells formed by urging the unconnected portions of adjacent sheets apart contain in-fill.
In one embodiment of the invention the in-fill is soil.
In another embodiment of the invention the in-fill is aggregate.
In a further embodiment of the invention the in-fill is hard-core.
In a still further embodiment of the invention the in-fill is concrete.
Further, the invention provides a land erosion preventative device comprising the reinforcing structure according to the invention, wherein the reinforcing structure is located in the ground and the cells formed by urging the non-engaging portions of adjacent sheets apart from each other contain in-fill.
In one embodiment of the invention the land erosion preventative device is adapted for preventing coastal erosion, and is located on or adjacent the sea shore.
In another embodiment of the invention the land erosion preventative device is adapted for preventing river erosion, and is located on or adjacent a riverbank.
Additionally, the invention provides a method for preventing soil erosion, the method comprising the steps of placing the reinforcing structure according to the invention in or on the soil, and back-filling the reinforcing structure with in-fill material into cells formed in the reinforcing structure by urging the unconnected portions of adjacent sheets apart from each other.
Further the invention provides a method for forming a cellular honeycomb type reinforcing structure wherein the method comprises locating a plurality of sheets extending substantially parallel to each other, gripping each sheet at a plurality of locations spaced apart along the length of the sheet by respective gripping means, so that each sheet is clamped at locations intermediate respective alternate first and second locations spaced apart along the length of the sheet, urging the gripping means of each sheet towards a mid-point of the sheet intermediate the respective longitudinal ends thereof for causing the sheets to bend adjacent the first and second locations along transversely extending bends, with the first locations of alternate sheets being displaced out of the plane of the corresponding sheet in a first direction, and the first locations of the other sheets being displaced out of the plane of the corresponding sheet in a second direction opposite to the first direction for engaging the first locations of an adjacent one of the sheets on one side thereof, the second locations of each sheet being displaced out of the plane of the sheet in a direction opposite to the direction in which the first locations of that sheet are being displaced for engaging the second locations of an adjacent one of the sheets on the other side thereof.
In one embodiment of the invention adjacent pairs of sheets are secured at their respective first and second locations.
In one embodiment of the invention the bends at the first and second locations are induced into the sheets by the gripping means as the gripping means commence to move towards the mid-points of the respective sheets.
In another embodiment of the invention each gripping means comprises a clamping means for clamping the corresponding sheet therebetween.
In one embodiment of the invention the sheets are of lattice structure material defining a plurality of openings therethrough, and the gripping means are urged towards the midpoints of the sheets until portions of the first locations and portions of the second locations of adjacent pairs of sheets inter-engage for defining respective retaining bores.
In a further embodiment of the invention the sheets are secured at the first and second locations by a retaining means for retaining the inter-engaged portions of the respective first and second locations inter-engaged.
Advantageously, the method further comprises the step of inserting the retaining means into the respective retaining bores at the first and second locations for retaining the respective inter-engaged portions engaged with each other.
Preferably, each retaining means comprises an elongated retaining bar, and the respective elongated retaining bars are inserted into the corresponding retaining bores, the retaining bores extending substantially transversely of the length of the sheets.
In an alternative embodiment of the invention the sheets are secured at each one of the first and second locations at two spaced apart locations for defining the retaining bores.
Further the invention provides a method for forming a cellular honeycomb type reinforcing structure wherein the method comprises sequentially securing a plurality of sheets to their adjacent sheets by supporting the sheet to which the next sheet is to be secured, displacing ones of first and second locations of the supported sheet out of a plane containing the others of the first and second locations of the supported sheet for engaging the corresponding ones of the first and second locations of the next sheet, securing portions of the supported sheet to the said next sheet at the ones of the first and second locations which have been displaced from the plane containing the others of the first and second locations.
In one embodiment of the invention adjacent pairs of sheets are secured at their respective first and second locations.
In another embodiment of the invention the sheets are of lattice structure material defining a plurality of openings therethrough, and the supported sheet and the said next sheet are secured at the ones of the first and second locations by inter-engaging portions of the supported sheet and the said next sheet at the ones of the first and second locations.
In one embodiment of the invention the sheets are secured at the first and second locations by retaining the inter-engaged portions of the supported sheet and the said next sheet at the first and second locations inter-engaged with respective retaining means.
In an alternative embodiment of the invention the sheets are secured at each one of the first and second locations at two spaced apart locations for defining the retaining bores.
In another embodiment of the invention prior to each said next sheet being secured at the corresponding one of the first or second locations, each said next sheet is bent along its respective first and second locations, so that the first locations are displaced to one side of the plane of the sheet, and the second locations are displaced to the opposite side of the sheet.
In a still further embodiment of the invention each supported sheet is supported at spaced apart locations by respective ones of spaced apart first engaging means and second engaging means, and is engaged by the other ones of the respective first and second engaging means at spaced apart locations intermediate the locations at which the supported sheet is supported for holding the supported sheet, so that by moving the ones of the first and second engaging means which are supporting the sheet relative to the others of the first and second engaging means, the supported sheet is bent at its respective first and second locations.
The invention also provides apparatus for forming a reinforcing structure according to the invention wherein the apparatus comprises a plurality of sets of clamps defining respective parallel clamping planes, each set of clamps being provided for gripping a corresponding one of the sheets at a plurality of gripping locations spaced apart along the length of the sheet, the clamps of the respective sets being moveable in their respective clamping planes in a direction towards a mid-point of the corresponding sheet intermediate the longitudinal ends thereof for causing alternate portions of the sheets to be displaced on opposite sides of the planes of the corresponding sheets for forming the first and second locations, so that the first locations of each sheet engages the first locations of the adjacent sheet to one side thereof, and the second locations of each sheet engage the second locations of the sheet on the other side thereof.
In one embodiment of the invention a means for applying respective retaining means to the engaged first and second locations of the respective sheets is provided for retaining the engaged first and second locations secured.
In another embodiment of the invention the means for applying the respective retaining means comprises a means for inserting respective retaining bars into corresponding retaining bores defined by the engaged portions of the respective first and second locations of adjacent sheets.
The invention further provides apparatus for forming a reinforcing structure according to the invention, wherein the apparatus comprises a plurality of spaced apart first engaging means and a plurality of spaced apart second engaging means located intermediate the first engaging means, the first and second engaging means being provided for alternately supporting and engaging alternate sheets sequentially on respective opposite sides thereof at spaced apart locations along the length of the sheet, the first engaging means defining a first plane, and the second engaging means defining a second plane, the first and second engaging means being moveable relative to the other for spacing the first and second planes apart for displacing alternate portions of the sheet being supported on the ones of the first and second engaging means on respective opposite sides of the plane of the sheet for forming the first locations on one side of the plane of the sheet, and the second locations on the other side of the plane of the sheet, so that the next sheet to be assembled engages portions of the ones of the first or second locations of the supported sheet.
In one embodiment of the invention a means is provided for bending each said next sheet to be assembled for forming respective first and second locations in the said next sheet for engaging the corresponding ones of the first and second locations in the supported sheet.
In another embodiment of the invention a means is provided for bringing each said next sheet into engagement with the supported sheet.
In a further embodiment of the invention the sheets are of lattice type structure defining a plurality of openings therethrough, and portions of the ones of the first and second locations of the supported sheet and the said next sheet are inter-engaged adjacent the said ones of the first and second locations.
The advantages of the invention are many. By virtue of the fact that the reinforcing structure is a cellular structure comprising a plurality of cells for containing in-fill, such as aggregate, soil or the like, the structure itself not only acts to contain and retain the in-fill material, but the structure extends through the in-fill material, thus further reinforcing the in-fill material. This is in contrast to known structures which essentially comprise a six-sided cage which contains in-fill material, typically, aggregate. By virtue of the fact that such cages only comprise external sides, namely, the six sides, if one of the sides ruptures, the aggregate spills out of the cage. Whereas in the reinforcing structure according to the invention, even if one portion of the reinforcing structure fails, only one cell becomes defective. The remaining cells still continue to contain and retain the in-fill material therein.
The provision of retaining means in the form of retaining bars has a further advantage, in that the retaining bars can be of length longer than the width of the sheets, thereby facilitating driving of the retaining bars into the soil beneath the reinforcing structure to act as piles. However, it will be readily apparent to those skilled in the art that piles may be driven through the reinforcing structure through any of the cells formed by the reinforcing structure when the unconnected portions of the respective sheets are urged apart.
The reinforcing structure according to the invention is therefore particularly suitable as a barrier or indeed a breakwater against coastal, river and lake erosion.
As well as the reinforcing structure being advantageous against coastal, river and lake erosion, the reinforcing structure according to the invention is also suitable for the prevention of soil erosion by wind, and is particularly suitable for locating along embankments of motorways and the like for preventing soil erosion by wind. Indeed, the reinforcing structure according to the invention is particularly suitable for preventing soil erosion on motorway embankments, and indeed, on other embankments until grass or other suitable binding vegetation has commenced to grow in the soil.
The apparatus and method according to the invention for forming the reinforcing structure also provide many advantages, in particular, they provide the advantage of being a relatively simple, effective and inexpensive apparatus and method.
The invention will be more clearly understood from the following description of some preferred embodiments thereof, which are given by way of example only, with reference to the accompanying drawings, in which:
a) to (c) are diagrammatic end views of apparatus for forming a cellular reinforcing structure according to the invention,
Referring to the drawings and initially to
The sheets 5 forming the cellular reinforcing structure 1 are of semi-rigid plastics material, and comprise a plurality of spaced apart parallel longitudinally extending members 9 which extend along the length of the sheets 5, and which are joined by a plurality of spaced apart parallel transverse members 8 which extend transversely of the length of the sheets 5. The transverse members 8 and longitudinal member 9 define a plurality of openings 13. The sheets 5 are bent to form a plurality of apices 10 which inter-engage each other at alternate respective first and second locations 11 and 12 to define a plurality of retaining bores 14. Retaining means provided by retaining bars 15 are located in each retaining bore 14 for retaining the respective apices 10 of adjacent sheets 5 inter-engaged. The apices 10 of adjacent sheets 5 inter-engage each other by portions of the longitudinal members 9 of each of the adjacent sheets 5 engaging corresponding ones of the openings 13 of the other sheet 5 so that the respective portions of the adjacent sheets 5 inter-engage each other and define the retaining bores 14. The sheets 5 as will be described below are shaped during forming of the cellular reinforcing structure 1 so that alternate portions of each sheet 5 are displaced on respective opposite sides of a plane defined by the sheet such that on one side of the plane the displaced portions form the first locations 11, and on the other side of the plane the displaced portions form the second locations 12. Each sheet 5 is thus joined to its adjacent sheet 5 on one side thereof by the first locations 11 of the two sheets 5 inter-engaging each other, and each sheet 5 is joined to the sheet on its other side by the second locations 12 of the adjacent sheets inter-engaging each other.
Each retaining bar 15 is hollow having a longitudinally extending axial receiving bore 16 extending therethrough. Securing means comprising securing members 19, each of which comprises a pan head 20 and a spigot 21 extending from the pan head 20 engage the axial receiving bores 16 at the respective opposite ends of the corresponding retaining bars 15 for securing the top sheet 6 and the bottom sheet (not shown) if desired to the cellular reinforcing structure 1. Barbs 22 are provided on the spigot 21 of each securing member 19 for engaging and retaining the securing members 19 in the corresponding receiving bores 16 of the corresponding retaining bars 15.
Each top sheet 6 and bottom sheet (not shown) is of semi-rigid plastics material, and comprises a plurality of longitudinally extending members 23 and transversely extending members 24. The longitudinal and transverse members 23 and 24 define openings 25. The top sheet 6 and the bottom sheet (not shown), which are similar, are of significantly smaller mesh size than the sheets 5, and the openings 25 are of size to accommodate the spigots 21 of the securing members 19 therethrough but are of size such that the pan heads 20 of the securing members 19 do not pass therethrough. Thus, when the top and bottom sheets are positioned relative to the cellular reinforcing structure 1, the top and bottom sheets can readily easily be secured to the cellular reinforcing structure 1 by the securing members 19 by inserting the spigots 21 through the opening 25 in the top and bottom sheets, and in turn engaging the spigots 21 in the receiving bores 16 in corresponding ones of the retaining bars 15.
In use, with the sheets 5 secured at their inter-engaged first and second locations 11 and 12 by the retaining bars 15, the cellular reinforcing structure 1 may be provided in a collapsed state, or in an erected state. In the collapsed state the sheets 5 are located relatively close to each other, and to erect the cellular reinforcing structure 1 from the collapsed to the erected state, unconnected portions 26 of adjacent sheets 5 between adjacent pairs of first locations 11, and second locations 12 are urged away from each other, thereby erecting the cellular reinforcing structure 1 and forming the cells 3. If it is desired to attach a bottom sheet (not shown) to the underside of the cellular reinforcing structure 1, the bottom sheet is secured to the underside of the cellular reinforcing structure 1 by an appropriate number of securing members 19 which are passed through openings similar to the openings 25 in the top sheet 6 into the receiving bores 16 of the corresponding retaining bars 15.
The cellular reinforcing structure is then placed on or into a cutting in the ground, and back-filled with appropriate in-fill material into the cells 3. Where mounted along a coastline, the cells are typically back-filled with suitable aggregate material, for example, stones, shingles, rubble or other suitable rock armour material. Where the cellular reinforcing structure is to prevent soil erosion, for example, on the embankment of a motorway and the like, the cellular reinforcing structure is placed on a subsoil base, and then the cells 3 are back-filled with top soil. Similarly, where the cellular reinforcing structure is to prevent erosion of sand from a sand dune and the like, the reinforcing structure is placed on the sand dune or in a cutting in the sand dune and the cells 3 are back-filled with sand.
Thereafter, if it is desired to place a top sheet 6 over the cellular reinforcing structure 1, the top sheet 6 is laid over the top of the back-filled cellular reinforcing structure 1 and secured thereto by an appropriate number of securing members 19 with the spigots 21 thereof extending through openings 25 in the top sheet 6 and into corresponding receiving bores 16 in the retaining bars 15.
Where the cellular reinforcing structure 1 is located for preventing soil erosion on a motorway embankment, the back-filled top soil in the cellular reinforcing structure 1 can then be sowed with grass seed or other vegetation suitable for binding the soil. Indeed, it is envisaged in certain cases that where the cellular reinforcing structure 1 is being used for preventing soil erosion on a motorway embankment or the like, and the in-fill soil in the cellular reinforcing structure 1 is being subsequently sown with grass seed or other suitable vegetation, the top sheet 6 may be omitted altogether.
Where it is desired to secure the cellular reinforcing structure 1 in or on the ground by piles (not shown), the piles are passed through the cells 3 and driven into the ground beneath the structure. With the piles extending through the cells 3 to the top thereof, or to a position intermediate the top and bottom of the cells 3, the cells 3 are then back-filled with the in-fill material.
The cellular reinforcing structure 1 of
Referring now to
Otherwise, the cellular reinforcing structure 30 and its use is similar to that of the cellular reinforcing structure 1.
Referring now to
A monitoring means (not shown), which may be provided by a photo sensor or any other suitable sensor is provided for monitoring when the apices 10 adjacent the first and second locations 11 and 12 inter-engage each other, and the inserting means (also not shown) for inserting the retaining bars 15 into the retaining bores 14 is responsive to the monitoring means.
Once the clamps 42 have been disengaged and withdrawn from the cellular reinforcing structures 1 and 30, the cellular reinforcing structures 1 and 30 are ready for use. The cellular reinforcing structures 1 and 30 may be collapsed by urging the sheets 5 together in concertina type fashion for ease of transportation. Alternatively, the cellular reinforcing structures 1 and 30 may be supplied in the erected state. However, where the cellular reinforcing structures 1 and 30 are supplied in the collapsed state, they can be readily erected into the erected state by urging the unconnected portions 26 of the sheets apart from each other with a concertina type action, which is the reverse of that used for collapsing the cellular reinforcing structures 1 and 30.
Referring now to
In this embodiment of the invention each sheet 5 is bent prior to engagement of the sheet 5 with the last of the sheets 5 to have been assembled to the cellular reinforcing structure 1 or 30, see
Referring now to
When placed on or in a cutting in the soil, the reinforcing structure 70 is backfilled with infill material in similar fashion to that described with reference to the reinforcing structure 1.
The reinforcing structure 70 may be manufacture using either of the apparatus 40 or 60 which have already been described with reference to
Otherwise, manufacture and use of the cellular reinforcing structure 70 is substantially similar to that described with reference to the cellular reinforcing structure 1 of
It will be appreciated that instead of the sheets 5 being retained together by a retaining means extending through the inter-engaged portions of adjacent sheets, the sheets may be retained together by welding. It is also envisaged that the sheets would preferably be welded adjacent their points of contact where the respective sheets inter-engage for forming the retaining bores. In which case, a retaining means may or may not be provided, however, the function of such a retaining means in such case would be more as piles for anchoring the cellular reinforcing structure.
It is also envisaged that securing means other than those described for securing a top sheet to the cellular structure may be provided. For example, it is not essential that the securing means should engage the retaining means. It is envisaged in certain cases, that the securing means could be engaged directly into the bores defined by the inter-engaged portions of the sheets. Furthermore, in certain cases, it is envisaged that the securing means may be engaged in the bore between the inter-engaged portions of the sheets and an adjacent retaining means. It is also envisaged in certain cases that where the retaining means is provided by an elongated bar, the top end of the bar may be barbed for securely receiving a securing means in the form of a cap which would extend downwardly over and around the outer periphery of the bar. Needless to say, it will be appreciated that while the retaining bars have been described as being tubular, they may be provided as solid bars.
While the sheets 5 and the top and bottom sheets have been described as being of semi-rigid plastics material, the sheets 5 may be of any other suitable material, whether plastics material or otherwise, and it is not essential that the sheets be of semi-rigid material, the sheets may be of a rigid type material, or indeed, they may be of a substantially flexible material. It will also be appreciated that while the sheets 5 have been described as comprising a plurality of longitudinally extending members which are parallel to each other and a plurality of transverse members which are also parallel to each other, the sheets may be provided in any desired form, provided that the sheets 5 are of lattice type construction defining a plurality of openings therethrough for facilitating inter-engagement of solid portions of the respective sheets with adjacent corresponding openings of adjacent sheets.
While the cellular reinforcing structure has been described for coastal, river, lake, soil and wind erosion, it will be readily apparent to those skilled in the art that the cellular reinforcing structure according to the invention may have many other uses.
One of the advantages of the invention is that it provides a cellular structure with a plurality of cells which can be filled with any suitable material, and in fact, when one considers the bores formed by the inter-engaging sheets the bores are also in the form of small cells. Accordingly, the cellular structure according to the invention comprises a series of alternate large and small cells, the large cells being those identified by the reference numeral 3 in the drawings, and the small cells being the bores identified by the reference numeral 14 in the drawings.
While the sheets 5 of the cellular reinforcing structure of
It will also be appreciated that while it is advantageous to secure the sheets 5 of the reinforcing structure of
| Number | Date | Country | Kind |
|---|---|---|---|
| S2001/1060 | Dec 2001 | IE | national |
This application is a continuation of U.S. Ser. No. 10/498,557 filed Dec. 27, 2004, which is a national stage entry of PCT/IE02/00169 filed Dec. 12, 2002, which claims priority from Irish Patent Application No. S2001/1060 filed Dec. 12, 2001, the disclosures of which are incorporated herein in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10498557 | Dec 2004 | US |
| Child | 12108794 | US |
