AUSTRALIA PATENTS ACT 1990 SPECIFICATION A SKATEBOARD The following statement is a description of the invention: 1 A SKATEBOARD TECHNICAL FIELD The present invention is directed to a skateboard and particularly a 5 skateboard with a particular type of reinforced deck. BACKGROUND A skateboard is typically as illustrated as in Figure 1 and comprises a deck 11, 10 two trucks 12, and wheels 13 attached to each truck via bearings. The deck is the most important part of a skateboard and the deck shape, size, thickness, profile and manufacture can change the performance characteristics of the skateboard. The deck is typically made from ply sheets 15 bonded together and a 7 ply deck is a standard manufacture. The trucks hold the wheels on and act as a kind of axle. They also allow the skateboard to tilt from left to right. 20 The wheels are usually made of polyurethane and come in different sizes and harnesses. The wheels affect the smoothness of the ride on a skateboard and the speed. The length of the deck can vary but for most ply skateboards the deck length 25 is between 27-33 inches or about 60-85 cm. While the deck will sag a little when a person stands on the deck, too much sag will negatively affect the performance characteristics of the skateboard. If the deck is too long, undesirable sagging can occur. 30 Various attempts have been made to reinforce the deck but without making the deck too stiff which can cause performance loss. Most of these attempts include the use of a special layer in the deck laminate, the special layer 2 including carbon fiber, Kevlar and the like. This adds to the cost of manufacture. Also, there is an advantage in reinforcing only certain parts of the deck to 5 prevent unnecessary sagging but to still maintain performance. There are advantages in manufacturing the skateboard deck from plastic. One advantage is a lower cost of manufacture. Another advantage is the ability to provide different shapes. There may be further advantages. 10 A disadvantage with plastic skateboards and especially skateboards made of inexpensive plastics is that to keep the deck relatively thin to enable it to flex so as to keep the performance characteristics of the board, the board can only be manufactured in smaller lengths ( typically up to a maximum of 22 inches). 15 A plastic board larger than 22" - especially as large as 27" without additional reinforcement causes it to 'bottom out' which means it hits the ground when skating if it isn't stiff enough. This makes the board perform poorly and causes a potential purchaser to buy a timber board instead). 20 Plastic skateboards cannot therefore be inexpensively manufactured in the longer style skateboards (namely up to 27 inches). The reason for this is that a suitable reinforcement device or area was never able to be designed to enable plastic skateboards to be made longer and 25 typically a length of 27 inches and possibly longer. Reinforcements for boards made of other materials may also have disadvantages including the cost in incorporating the reinforcement. 30 Any references to methods, apparatus or documents of the prior art are not to be taken as constituting any evidence or admission that they formed, or form part of the common general knowledge.
3 It is an object of the present invention to provide reinforcement for skateboards and especially plastic skateboards. SUMMARY OF THE INVENTION 5 According to a first aspect of the present invention there is provided a skateboard deck comprising a bottom wall, a cavity in the bottom wall and located between truck attachment points, and a strengthening member extending across the cavity and attached to the deck, the member comprising 10 a closed loop member. According to another aspect of the present invention there is provided an especially reinforced area on a plastic skateboard including: a first portion being a base plate for the reinforced area 15 a second portion being an oval shaped ring a third portion where the first and second portions amalgamate wherein the first portion is attached or manufactured as part of the skateboard to the bottom of a skateboard, and the second portion is attached to the first portion, result in the third portion, to provide sufficient strength to 20 enable the manufacturing of long plastic skateboards. While not wishing to be bound by theory, the closed loop member (e.g. an oval shaped ring) can function to gain the extra strength needed to balance the forces of weight on the board and keep the platform strong enough as 25 required, and can keep high performance characteristics by providing a perfect balance of stiffness and flexibility. The cavity can comprise a hollow in the bottom wall of the deck to make this part of the deck thinner and thus more flexible to provide performance to the 30 skateboard. The strengthening member can provide the required strength without totally compromising the performance of the board. This combination can allow a longer board to be manufactured from plastic materials.
4 It is an object of the present invention to provide reinforcement for skateboards and especially plastic skateboards. SUMMARY OF THE INVENTION According to a first aspect of the present invention there is provided a skateboard 5 deck comprising a unitary, plastic body having a bottom wall, a pair of raised truck attachment points spaced on said bottom wall, a pair of spaced stiffening ribs formed integrally with the body and extending between the front and rear truck mounting platforms and defining therewith a cavity, and a closed loop, integral strengthening member formed in the deck and extending over the cavity. 10 The closed loop, integral strengthening member may extend to and be integrated with each of the front and rear truck mounting platforms. The strengthening member may comprise an oval shaped ring. The unitary, plastic body may be formed of polypropylene by injection moulding. While not wishing to be bound by theory, the closed loop member (e.g. an oval 15 shaped ring) can function to gain the extra strength needed to balance the forces of weight on the board and keep the platform strong enough as required, and can keep high performance characteristics by providing a perfect balance of stiffness and flexibility. The cavity can comprise a hollow in the bottom wall of the deck to make this part 20 of the deck thinner and thus more flexible to provide performance to the skateboard. The strengthening member can provide the required strength without totally compromising the performance of the board. This combination can allow a longer board to be manufactured from plastic materials. The cavity can be formed during manufacture of the deck. Alternatively the cavity 25 can be in a separate part or portion that can be fitted by any suitable means to the deck, or to another part (e.g. a top platform) which together form the deck. A separate part may be provided comprising a base plate. The base plate can be made from plastics or other suitable material. The base plate can be attached to a skateboard deck to provide strength. Alternatively a platform can be fitted to the 5 base plate such that the combination of the base plate and the platform constitutes the skateboard deck. The base plate can comprise a main body portion, a forward tongue portion and a rear tongue portion. The tongue portions may be of reduced size relative to the 5 main body portion. The forward tongue portion and the rear tongue portion may, in use, be attached to a forward and rear truck, inter alia, to improve security and stability to the skateboard. The cavity is preferably in the main body portion and preferably substantially comprises the main body portion. Thus the main body portion preferably 10 comprises an inner or back wall and a raised wall to define the cavity. The raised wall may entirely surround the back wall or may extend only partially about the back wall. Multiple separate walls may also be present. A function of the raised wall is to provide performance and strength to the formed deck, so it is preferred that the wall entirely surrounds the back wall. 15 The strengthening member can be associated with the cavity in the base plate. The strengthening member may comprise a second part which is separate from the first part and attached thereto. Alternatively, the strengthening member may be formed integrally with the first part. The strengthening member comprises a closed loop member. Suitably, the 20 member comprises an oval shaped ring member. Suitably the loop member comprises only straight or rounded parts and does not include any angled 6 FIG. 1 is a top perspective view of a skateboard according to an embodiment of the invention. FIG. 2 is a top plan view of FIG. 1. FIG. 3 is a bottom plan view of FIG.1 and particularly illustrating the invention 5 FIG. 4 is a front elevational view of FIG. 1 FIG. 5 is a rear elevational view of FIG. 1 FIG. 6 is a left-side elevational view of FIG. 1, the right-side elevational view being a mirror image thereof; FIG. 7 is a bottom plan view of FIG. 1 with wheels and extraneous matter 10 removed. FIG. 8 is an enlarged view of FIG. 7 FIG. 9 is an enlarged view of the strengthening loop member. FIG. 10 is a perspective view of a plastic skateboard according to an embodiment of the invention under torsion showing the forces thereupon. 15 FIG. 11 is a perspective view of a upwardly bent plastic skateboard according to an embodiment of the invention and showing the forces thereupon FIG. 12 is a perspective view of a bowed plastic skateboard according to an embodiment of the invention showing the forces thereupon FIG. 13 is a perspective view of a prior art torted plastic skateboard showing 20 the forces thereupon FIG. 14 is a perspective view of a prior art upwardly bent plastic skateboard, showing the forces thereupon FIG. 15 is a perspective view of a prior art bowed plastic skateboard showing the forces thereupon. 25 DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Referring to the drawings and initially to figure 1 there is shown a skateboard 10 which comprises a deck 11, a pair of trucks 12, each truck supporting a 30 pair of wheels 13. The skateboard according to the embodiments of the invention has a special design making it particularly useful in the manufacture of longer plastic skateboards. Thus, and particularly referring to figure 3, the skateboard deck 7 11 has a bottom wall 23. A cavity 14 is provided in the bottom wall and formed between spaced strengthening ribs forming walls 22 and the forward truck and rear truck 12. A closed loop strengthening member 15 extends across cavity 14. The strengthening member 15 is attached to the bottom wall 23 adjacent opposed 5 end thereof. The embodiment of figure 3 illustrates that the bottom wall of the deck 11 contains the cavity 14. Thus, in this particular embodiment the cavity is formed integrally with the deck and in the bottom wall of the deck. Figure 8 illustrates a further embodiment where the parts of the present invention 10 are formed separately and then attached to the bottom of the deck of a skateboard and particularly a plastic skateboard. Referring to figure 8, there is illustrated a base plate 16 which has a larger main body portion 17 and front and rear tongue portions 18, 19 which can all be integrally formed. The tongue portions 18, 19 can contain truck attachment points 20 such that the entire base plate 16 can be 15 securely fastened to the underside of the skateboard. Main body portion 17 contains the cavity 14, and the cavity is defined by a back wall 21 and a surrounding raised wall 22. Strengthening members 15 extends in a generally longitudinal manner across cavity 14 and is connected to the base plate 16 by any suitable means and adjacent the rear of each tongue portion 18, 19. 20 The strengthening member 15 and base plate 16 can be formed from plastic. The combination of the part containing the cavity and the strengthening member can provide sufficient strength to enable the manufacturing of long plastic skateboards. The plastic board is manufactured using a plastic injection moulding production 25 method where plastic is injected into a mould under very high pressure. The method prevents addition of strengthening rods into the plastic 8 board. An advantage of the present invention is that the strengthening member [ i.e. the ring] is part of the mould design and not a separate member inserted into the mould. 5 With this combination in place, plastic skateboards are able to tort, bend and bow with forces shown on FIGS. 10, 11, 12. Without the combination in place, plastic skateboards were unable to tort, bend and bow with forces shown on FIGS. 13, 14, 15. 10 Until now, such torting and twisting was unable to be achieved with longer plastic skateboards of 27 inches in length, resulting in the inability to use the skateboard for intended purposes, due to the skateboard bottoming out, or being too strong. If the perfect balance is not obtainable in a plastic board, a 15 timber board will be purchased instead. It is preferred that the combination does not unduly protrude on the bottom of the skateboard, as illustrated in Figure 1. 20 Additional strength may be provided to the plastic deck by profiles on the top of the deck, which can provide lineal and lateral strength. In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. The term 25 "comprises" and its variations, such as "comprising" and "comprised of' is used throughout in an inclusive sense and not to the exclusion of any additional features. It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect. The invention is, 30 therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted by those skilled in the art. Throughout the specification and claims (if present), unless the context requires otherwise, the term "substantially" or "about" will be understood to 9 not be limited to the value for the range qualified by the terms. Any embodiment of the invention is meant to be illustrative only and is not meant to be limiting to the invention. Therefore, it should be appreciated that 5 various other changes and modifications can be made to any embodiment described without departing from the spirit and scope of the invention.