Patent Application
20060283140
The present invention relates to wooden decks and floors such as may be used in ships, yachts, foot bridges, balconies, pool sides, piers, marinas and other vessels and structures.
Wooden decks are used in many locations to provide a comfortable and attractive surface for people to walk upon, for example on the decks of cruise ships and other pleasure boats and in public and private buildings such as hotels on balconies, walkways, poolsides, etc. Conventionally, a wooden deck is laid by covering the base surface, e.g. concrete or steel, with a layer of plywood on which is laid the decking, e.g. teak planks. The plywood layer provides a degree of cushioning to the deck, making it more comfortable to walk on and also providing a degree of sound absorption.
Through use, the wooden deck will experience wear and may also suffer due to exposure to the elements. Accordingly the deck and plywood layer will eventually need replacement. In many cases, the underlying base may have deteriorated due to water penetration or internal stresses and may no longer be sufficiently flat. Accordingly, before the replacement plywood layer and decking can be laid, a self-leveling screed must be applied. This is time consuming and known self-leveling screeds do not provide an appropriate backing for the deck.
There is therefore a need for an improved manner of constructing a wooden deck or floor.
According to the present invention, there is provided a deck member comprising:
a structural sandwich plate member comprising first and second plates and a core of plastics or polymer material bonded to said first and second plates with sufficient strength to transfer shear forces therebetween; and
a layer of wood attached to an outer face of said first plate.
The present invention also provides a method of manufacturing a deck member comprising:
forming a structural sandwich plate member comprising first and second plates and a core bonded to said first and second plates with sufficient strength to transfer shear forces therebetween; and
fixing a wooden layer to said first plate.
The present invention will be described below with reference to exemplary embodiments and the accompanying schematic drawings, in which:
In the various drawings, like parts are indicated by like reference numerals.
The wooden deck member 10 shown in
The materials, dimensions and general properties of the plates of the structural sandwich plate member of the invention may be chosen as desired for the particular use to which the structural sandwich plate member is to be put and in general may be as described in U.S. Pat. No. 5,778,813 and U.S. Pat. No. 6,050,208. Steel or stainless steel is commonly used in thicknesses of 0.5 to 20 mm and aluminum may be used where light weight is desirable. Aluminum in general may be used in thicknesses 2 to 4 times that of steel, i.e. 1 to 50 mm, to give comparable strength. Similarly, the plastics or polymer core may be any suitable material, for example an elastomer such as polyurethane, as described in U.S. Pat. No. 5,778,813 and U.S. Pat. No. 6,050,208.
The structural sandwich plate member comprises upper (first) and lower (second) plates 11, 12 which may be of steel or stainless steel (e.g. of thickness in the range of from 0.5 to 20 mm) or aluminum (e.g. of thickness in the range of 1 to 50 mm). Edge plates (not shown) are welded or adhered between the plates 11, 12 around their outer peripheries to form a closed cavity. Alternatively, the structural sandwich plate member may be assembled in a mold, obviating the need for edge plates. In the cavity between the plates 11, 12 is a core 13 of plastics or polymer material, preferably compact (i.e. not a foam) and preferably a thermosetting material such as polyurethane elastomer. This core may have a thickness in the range of from 15 to 200 mm. The core 13 is bonded to the plates 11, 12 with sufficient strength and has sufficient mechanical properties to transfer shear forces expected in use between the two plates.
The required bond strength between the core 13 and plates 11, 12 will depend on the exact use the deck member is to be put. If the deck member is required to contribute significantly to strength of the structure of which it is to be a part, the bond strength should be greater than 3 MPa, preferably 6 MPa, and the modulus of elasticity of the core material should be greater than 200 MPa, preferably 250 MPa. A lower modulus may be used where high temperature conditions will not be experienced. For low load applications, where the typical use and occupancy loads are of the order of 1.4 kPa to 7.2 kPa, the bond strength may be lower, e.g. approximately 1 MPa. By virtue of the core layer, the deck member has a strength and load bearing capacity of a stiffened steel plate having a substantially greater plate thickness and significant additional stiffening. The member, of course, need not be flat but may take any shape required for its intended use.
To reduce the weight of the plate member, a plurality of lightweight forms or inserts may be provided in the core. The forms 14 may comprise blocks of foam, extruded tubes, or hollow, solid skin polypropylene balls, for example. The forms in general need not contribute to the structural strength of the member and thus need only have sufficient strength and mechanical properties to withstand pressures and temperatures that will occur during injection of the core. In low-load applications, the core material may also include a low-density and low-cost filler such as coconut husk, cardboard or string.
The manufacturing of the panel may be performed in situ, or off-site in factory conditions and the finished panel transported to the installation site. The latter allows for automation of the process and improved dimensional accuracy, as well as more reliable bonding.
A method of manufacturing a deck according to a second embodiment of the present invention is shown in
After curing of the core material, the through-holes can be sealed, but this may not be necessary if they will be covered by the wooden layer or if the top plate 23 and core materiel are sufficiently water resistant.
Once the core material is fully cured, the top plate 23 presents a flat and level surface to which the wooden decking can be directly attached, e.g. by adhesive or by fittings provided on the top plate. One possibility is to bolt the wooden planks 24, 25 to the top plate 23 using the through-holes 26, which may be threaded for this purpose.
The core 22 provides a useful degree of sound deadening and also provides a comfortable feel to the deck. If desired, the thicknesses of the core and top-plate as well as the bond strength between the core and plates can be selected so that the resulting structural sandwich plate member has significant structural strength. The replacement wooden decking can therefore reinstate to design strength or upgrade the existing deck, allowing, in the case of vessels, removal of stiffening and/or pillars in the levels below the deck. In general, the same materials may be used for the core in the second embodiment as in the first. Also, the same forms, inserts and fillers may be employed.
The invention is also advantageous in that the structural sandwich plate member is robust and durable so that replacement of worn planks can in many cases be carried out without the need to repair or replace the structural sandwich plate member.
It will be appreciated that the above description is not intended to be limiting and that other modifications and variations fall within the scope of the present invention, which is defined by the appended claims.
