Description of Invention

The present invention relates to rackets for playing sports, e.g. tennis, squash, badminton, racquetball or the like. In particular, but not exclusively, the present invention relates to tennis rackets.

Rackets for playing sports are well known. Rackets typically include a handle for a user to grasp and a head connected to the handle. A strung surface is provided across the head with which to strike an object such as a ball or shuttlecock. The strung surface of a racket includes a central region, commonly referred to as the “sweet spot”, that provides the optimum response from the racket when striking an object such as a ball or shuttlecock. An issue with prior art rackets is that the size of the central region or “sweet spot” is relatively small with respect to the size of the head. Therefore, users of the racket typically obtain a less than optimum response from the racket.

It is an object of the present invention to provide an improved racket.

According to a first aspect of the invention we provide a racket for playing sports, including: a handle for a user to grasp; and a head connected to the handle including: a frame which defines a main opening having a periphery; openings in the frame for receipt of at least one string which extends across the main opening to form a strung surface for hitting an object in use, wherein the openings are spaced about the periphery and include first and second openings; and a guiding member which extends between the first and second openings for guiding a string between the first and second openings; wherein the frame includes at least two further openings positioned between the first and second opening.

The frame may be hollow.

The frame may define an enclosed space. The guiding member may be positioned in the enclosed space.

The guiding member may include a first end connected to the first opening.

The guiding member may include a second end connected to the second opening.

The guiding member may include a receiving formation for receiving a string in use. The receiving formation may extend between the first and/or second ends of the guiding member.

The receiving formation may be positioned within an interior of the guiding member.

A cross-section of the receiving formation may be generally circular.

A surface of the receiving formation may be relatively smooth for permitting a string to move relative to the guiding member.

The guiding member may extend through the first and/or second openings.

The guiding member may be generally elongate. The guiding member may be generally curvilinear and/or arcuate.

The guiding member may be relatively flexible.

The guiding member may be formed at least partially of nylon.

The guiding member may be formed at least partially of PTFE (polytetrafluoroethylene).

A cross-section of the guiding member may be generally circular.

The racket may include a fixation material in which the guiding member may be fixed.

The first opening may lie in a plane P. The second opening may lie in the plane P. The main opening may lie in the plane P.

The frame may include an inwardly facing surface. The inwardly facing surface may define the main opening. The first and second openings may be positioned on the inwardly facing surface.

The racket may include a plurality of first and second openings. The racket may include a plurality of guiding members which connect respective pairs of first and second openings. The guiding members may overlap, or pass, each other within the frame.

The racket may include a string which extends between the first and second openings for forming a strung surface for hitting an object in use. The racket, or frame, may include first, second and third layers. The first layer may be sandwiched between the second and third layers. The first layer may be formed of a first fixation material. The second and third layers may be formed of a second fixation material different to the first fixation material.

The frame may include an internal wall which defines a second, further, enclosed space E2. The guiding members may be positioned in the first enclosed space. The frame may include a second internal wall. The frame may include a third, further enclosed space E3. The guiding members may be positioned in the first enclosed space.

According to a second aspect of invention we provide a racket for playing sports including: a handle for a user to grasp; and a head connected to the handle including: a frame which defines a periphery of the head and which also defines an enclosed space; openings in the frame for receipt of strings which form a strung surface for hitting an object in use, wherein the openings are spaced about the periphery and include first and second openings; and a string which extends between the first and second openings for forming a strung surface for hitting an object in use; wherein the frame includes at least two further openings positioned between the first and second opening; and wherein the string passes through the first opening into the enclosed space and directly to the second opening.

The second aspect of the invention may include one or more or all of the features of the first aspect of the invention. According to a third aspect of the invention we provide a method of manufacturing a racket, including the steps of: providing a racket including a handle and a head connected to the handle, wherein the head includes a frame which defines a periphery of the head and also defines an enclosed space E; inserting at least one guiding member into the enclosed space E, wherein the at least one guiding member is relatively flexible and includes first and second ends and a receiving formation which extends between said ends, wherein a string may pass through the receiving formation; inserting a (first) fixation material for fixing the guiding member in position; and fixing the guiding member in position.

The frame may be provided in first and second frame portions.

The method may include the step of fixing the first and second frame portions together.

The method may include the step of inserting a second fixation material into the frame. The method may include the step of subsequently inserting the (first) fixation material.

The second fixation material may be provided in first and second portions. The first fixation material may be positioned between the first and second portions of the second fixation material.

The first portion of the second fixation material may be inserted into the first frame portion. The second portion of the second fixation material may be inserted into the second frame portion. The (first) fixation material may be inserted after the step of fixing the first and second frame portions together.

The step of inserting the at least one guiding member may be performed after the step of inserting the (first) fixation material.

The step of inserting the at least one guiding member may be performed before the step of inserting the (first) fixation material. The method may include the step of setting the fixation material in position.

The method may include the step of hardening the fixation material once the guiding members are in position. The method may include the step of cooling the fixation material once the guiding members are in position.

The method may include the step of forming a further, second, enclosed space E2 within the frame.

The method may include the step of inserting the (first) fixation material in the first enclosed space E1.

The method may include the step of inserting the guiding members in the (first) fixation material.

The second enclosed space may encapsulate the first enclosed space.

The method may include the step of forming a further third enclosed space E3 within the frame. The method may include the step of forming the enclosed space using an inflatable pressure bag.

The method may include the step of forming at least a portion of the racket using a mandrel.

The method may include the step of forming the enclosed space using a soluble core. The method may include the step of forming the enclosed space using a meltable core.

The method may include the step of forming the enclosed space using an expandable core.

The method may include the step of forming the enclosed space using a foam core.

The third aspect of the invention may include one or more or all of the features of the first and/or second aspects of the invention.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings of which: Figure 1 is a front view of a racket in accordance with the present invention;

Figure 2 is a perspective view showing a portion of the racket figure 1 with a section of the racket head removed; Figure 3 is a cross-sectional view along the line 3-3 of figure 1 ; Figure 4 shows a stringing pattern for the racket of figure 1;

Figure 5 is a front view of a racket to demonstrate where a ball was dropped on the racket for testing;

Figure 6 is a graph of the performance of the racket compared with the prior art;

Figure 7 is a cross-sectional view of a frame of a second embodiment of a racket in accordance with the present invention;

Figure 8 is a cross-sectional view of a frame of a third embodiment of a racket in accordance with the present invention; and Figure 9 is a cross-sectional view of a frame of a fourth embodiment of a racket in accordance with the present invention.

Referring to figure 1 there is shown a racket 10 for playing sports. In particular, the racket 10 is a tennis racket. In other embodiments the racket 10 may be a badminton racket, squash racket or racquetball racquet, or any other type of racket, without departing from the scope of the present invention.

The racket includes a handle 12 for a user to grasp in use having first and second ends 20, 22. A head 14 is connected to the handle 12. In particular, the head 14 is connected to the second end 22 of the handle 12, the second end 22 of the handle 12 being positioned closer to the head 14 than the first end 20. The head 14 is connected to the handle 12 by first and second elongate members 16, 18. In other embodiments only a single elongate member may be provided. The first and second elongate members 16, 18 may extend from the second end of the handle 12 towards the head 14. The first and second elongate members 16, 18 may also extend away from each other as they extend towards the head 14, away from the handle 12. In other embodiments the first and second elongate members 16, 18 may extend substantially parallel with respect to each other towards the head 14. The head 14 includes a main opening 15 across which a string, or strings, 43 extends in a woven pattern to define a strung surface S.

With reference to figure 1 and figure 3, the head includes a frame 30 which includes an inwardly facing surface 32 which faces towards the main opening 15 and which defines a periphery of the head 14. The frame 30 also includes an outwardly facing surface 35 which faces outwardly away from the main opening 15. The inwardly facing surface 32 is connected to the outwardly facing surface 35 by first and second frame connection portions 37, 39. The frame 30 is hollow and defines an enclosed space E that contains other components as will be later explained. In the present embodiment the frame 30 is annular and forms a closed loop. In particular, the frame may extend directly between the first and second elongate members 16, 18. In the present embodiment the frame 30 is integrally formed with the handle 12. However, in other embodiments the frame 30 may not be annular. For example, the frame 30 may be generally tear drop shaped to define a main opening and the racket has no elongate members 16, 18. In these embodiments, the frame 30 connects directly to the handle 12. In embodiments the frame may be formed separately from the handle. For example, the frame 30 may be formed and the handle 12 may be formed and then the frame 30 and handle 12 may be joined together using adhesive or other methods well known in the art.

In plan view (see figure 1), the inner and outer surfaces 32, 35 of the head 14 are generally oval shaped. However, in other embodiments this may not be the case. For example, the inner and outer peripheries 32, 35 may be circular, trapezoidal, or obround without departing from the scope of the present invention. Referring to figure 2 the frame 30 includes openings 40 which, in use, receive strings to form a strung surface S for striking a ball. In use, the strung surface S lies on the plane P. The openings 40 are spaced circumferentially around the inner surface 32 to permit a stringing of the racket 10 to form the strung surface S.

The openings 40 include first and second openings 42, 44. The openings 42, 44 are also spaced about the periphery 32. The first and second openings 42, 44 are positioned in the plane P. In other embodiments the first and/or second openings 42, 44 may be positioned either side of the plane P without departing from the scope of the present invention. As can be seen from figure 2, there are six openings between the first and second openings 42, 44. In the present embodiment, a single string 43 provides the strung surface. In other embodiments it could be a different number of strings, e.g. 2 or 3 etc. The string 43 extends directly between the first and second openings 42, 44 through the enclosed space E for at least partly forming the strung surface S. The term “first and second openings” is used to denote any pair of openings in the frame 30 for which the string 43 extends directly between to form part of the strung surface S. Therefore, the frame 30 includes a plurality of first and second openings forming respective pairs of openings. The first and second openings are provided on the same half of the frame as defined by a plane which extends along the handle 12 and which plane is orthogonal to the plane P. For example, the string 43 enters the frame 30 at opening 42 and leaves the frame 30 at opening 44 before then entering the frame 30 at a further opening (not shown) which is generally opposite the opening 44. The string 43 then passes through the frame 30 and leaves the frame at another further opening (not shown) which is spaced apart from the further opening such that there are at least two respective openings between them. In this way, the strung surface S is effectively formed through a plurality of pairs of first and second openings 42, 44 and between those openings there are at least two openings between them. Although six openings between openings 42, 44 are shown in the embodiment of figures 1 and 2, they may be arranged differently with at least two openings between the respective pairs of openings 42, 44. For example, three, four, five or more openings may be between the respective pairs of openings 42, 44. In embodiments the first and second openings may be provided on different halves of the frame as defined by a plane which extends along the handle 12 and which plane is orthogonal to the plane P, as shown in figure 4.

The provision of at least two openings 40 positioned between the first and second openings 42, 44 has been found to be advantageous. Such a spacing between the first and second openings 42, 44 has been found to increase the effective string length of the string 43 which in turn increases the area of the sweet spot on the racket. An increase in effective string length has also been found to improve a dwell time between the string 43 and the ball and improve the responsiveness of the racket 10, the controllability of the racket 10 and the ability to impart spin on the ball through the racket 10. In embodiments, it has been found that providing five openings 40 between the first and second openings 42, 44 has been particularly advantageous in increasing the effective string length of the string 43. It is thought that this is realised due to the correlation between a typical stringing pattern of a racket, as shown in figure 4, and a typical diameter of an object to be struck, i.e. a tennis ball. This has not previously been realised in the prior art.

The provision of at least two openings 40 positioned between the first and second openings 42, 44 has also been found to be advantageous because it improves the movement of the string 43 and thus the effective string length. For example, if a ball strikes a first portion of the string 43 on the strung surface S at a point after it exits the first opening 42 the ball will not strike a second portion of the string 43 on the strung surface S at a point after it exits the second opening 44. This enables the second portion of the string 43 adjacent the second opening 44 to move relative to the first portion of the string 43 adjacent the first opening 42 which therefore effectively increases the string length and dwell time between the ball and the first portion of the string 43. This is not possible in the prior art, where the string would pass directly through adjacent openings, it would not be possible for the string to increase in length in the same way as the present invention because there is no additional length of string that can move through the enclosed space E to provide an increased effective string length through any one of the openings and also because the ball would strike adjacent string portions that themselves pass through adjacent openings which means that one of the string portions cannot move through its opening to compensate for the other of the string portions.

The present invention also permits the tailoring of the properties of the strung surface S at different points on the strung surface S. This permits advantageous properties to be provided at different points of the racket 10 or tailored to a user’s specific requirements.

In more detail, referring to figures 2 and 3 there is shown a generally elongate and curvilinear and/or arcuate guiding member 50 for guiding the string between the first and second openings 42, 44. The guiding member 50 is positioned in the enclosed space E. The present embodiment includes a plurality of guiding members for guiding a string between respective first and second openings. The guiding members in the present embodiment overlap, or pass each other, as shown in figure 2. The guiding members are substantially the same and so only the guiding member 50 is described in detail.

The provision of guiding members is advantageous. The guiding members assist the string 43 in moving through the first and second openings 42, 44 both for installation and in use to increase the effective string length of the string 43. Providing the guiding member in the enclosed space E also improves the aerodynamics of the racket 10 which is advantageous compared to the prior art where the string 43 is provided on a grommet on an external surface of the racket 10.

The guiding member 50 includes first and second ends 52, 54 which are connected to the first and second openings 42, 44 respectively. In the present embodiment the first and second ends 52, 54 are positioned adjacent the first and second openings 42, 44. However, in other embodiments the first and second ends 52, 54 may pass through the first and second openings 42, 44. The guiding member 50 is relatively flexible. The guiding member 50 is formed from nylon. This is advantageous as it permits easy manufacture of the racket 10 including a plurality of guiding members. In other embodiments the guiding member 50 may be formed of a different material. For example the guiding member 50 may be formed of a thermoplastic material or a thermosetting material without departing from the scope of the present invention. In embodiments the guiding member 50 is formed from PTFE (polytetrafluoroethylene). In embodiments the guiding member 50 may be formed from chemically etched PTFE, e.g., the guiding member may be formed from PTFE and an exterior surface of the guiding member 50 may be chemically etched. This may be advantageous in improving the ability of a fixation material to bond to the guiding member. The fixation material is discussed in more detail below.

A receiving formation, in the form of a channel, 56 is provided within an interior of the guiding member 50. This is advantageous as it enables easy movement of the string 43 through the guiding member 50. In other embodiments the receiving formation may be a groove provided on an outer surface of the guiding member. The receiving formation 56 extends between the first and second ends 52, 54 of the guiding member 50. The guiding member 50 has a generally circular cross-section. The receiving formation 56 also has a generally circular cross-section. However, in other embodiments the guiding member 50 and/or receiving formation 56 may be at least partly arcuate, oval shaped, obround, trapezoidal or rectangular without departing from the present invention. The receiving formation 56 may include a surface 58 which is generally smooth. This may be advantageous for permitting a string to move relative to the guiding member.

The enclosed space E is filled with a fixation material 70 in which the guiding member 50 is fixed. The fixation material 70 in the present embodiment is low density, and in particular is a foamed resin. In other embodiments the fixation material 70 may be a lightweight filler without departing from the scope of the present invention. The fixation material may be a thermoplastic material or thermosetting material.

A testing method has been devised for the new improved racket embodying the present invention. For the testing method the racket is first placed on a flat surface such that the strung surface S is facing upwardly with respect to the flat surface. A fixed height above the racket is then set from which to drop a ball. A solid plastic ball is then dropped onto the strung surface S at different points on the strung surface S from the fixed height. For the present testing method the solid plastic ball weighs 163g and has a diameter of 70 mm. A height of 153 cm was chosen for the present test from which to drop the ball. The height that the ball reached following bouncing on the racket was then measured. A racket according to the present invention and an otherwise identical conventional racket were tested using this method. In particular, the rackets both had a head area of 98 square inches and were strung with Yonex Poly Tour Pro 1.25 strings at 62 lbs tension. The same ball and testing setup and method were used for each racket. The ball was dropped onto each respective racket at a series of locations as shown in figure 5. The strung surface S has been divided into quarters for testing. In particular a line H - H divides the strung surface S into a top side, furthest from the handle 12, and a bottom side, closest to the handle 12. A line V - V divides the strung surface S into first and second sides positioned to left and right sides of the line V -V respectively. The ball was dropped onto: a) Position 1 - the centre of the strung surface S where the lines H - H and V - V intersect; b) Position 2 - generally centrally in the bottom half of the strung surface S on the line V- V ; c) Position 3 - generally centrally of a top half of the strung surface S on the line V- V; d) Position 4 - generally centrally of the second side of the strung surface S on the line H - H; e) Position 5 - generally centrally of a quadrant of the strung surface S defined between the periphery 32 and the lines H -H and V - V on the bottom side of the strung surface S; and f) Position 6 - generally centrally of a quadrant of the strung surface S defined between the periphery 32 and the lines H -H and V - V on the top side of the strung surface S. The results of the testing are shown in figure 6. Figure 6 shows how much height, and thus energy, was lost from the ball once the ball had bounced on the strung surface. As can be seen from the testing the racket according to the present invention shows an improvement in the characteristics of the strung surface at least at positions 1 to 4 and similar characteristics to the prior art racket at positions 5 and 6. This is because less height is lost from the bounce height using a racket according to the present invention than a prior art tennis racket which is otherwise identical. Therefore the energy retained in the ball is higher when using a racket according to the present invention compared to the prior art. There is also provided a method for manufacturing a racket according to the present invention. The method involves first providing a racket 10 as described in relation to the first embodiment of the invention. The racket 10 includes a handle 12 and a head 14 connected to the handle 12. The head includes a frame 30 which defines an inner surface, or periphery, 32 of the head 14. The frame 30 also defines an enclosed space E. In the present embodiment at least a portion of the head 14 is integrally formed with the handle 12. In particular the racket 10 may be formed by a moulding process. In embodiments the racket may be provided in one or more parts. For example, the head 14 and the handle 12 may be formed separately and/or the frame 30 may be formed in two parts, or first and second halves divided by the plane P. In the present embodiment the frame is made of two parts with the outer surface 35 being formed by a part which is separate from a remainder of the frame 30. In embodiments the inner surface 32 may be formed separately from a remainder of the frame 30.

The provision of such parts, or halves, is advantageous for positioning the guiding members 50 in the frame 30 and for filling the frame 30 with fixation material 70. The parts, or halves, are later connected together to form the enclosed space E. This may be by a further moulding process, welding process, or gluing process, for example.

At least one guiding member 50 is provided in the frame 30. In the present embodiment a plurality of guiding members 50 are provided in the frame 30. In the manufacturing process once the frame 30 is formed the guiding members 50 are inserted into the frame 30. The guiding members 50 are received in the enclosed space E defined by the frame 30. In the present embodiment the guiding members 50 are inserted into the frame 30 in a direction towards the main opening 15 and the inner surface 32, before the outer surface 35 is connected to the remainder of the frame 30. In embodiments the guiding member 50 may be inserted into the frame 30 after the outer surface 35 is connected to the remainder of the frame 30.

The guiding members 50 are relatively flexible and include first and second ends 52, 54 and a receiving formation 56 which extends between said ends 52, 54 as previously described. In the present embodiment the openings at the ends of respective guiding members 50 are aligned with respective openings 40 through which the strings pass, in use. In particular, the first and second ends 52, 54 of the guiding members 50 are aligned with their respective openings 40 on the inner surface 32 of the frame 30. In envisaged embodiments the guiding members 50, or in particular the first and second ends 52, 54 of the guiding members 50, form the openings 40 in the frame 30 through which, in use, the strings 43 pass. The guiding members 50 may overlap, or pass, each other within the enclosed space E.

Once the guiding members 50 have been inserted a fixation material 70 is inserted into the racket 10 into the enclosed space E defined by the frame 30. The fixation material 70 fixes the guiding members 50 in position. The fixation material 70 may also fix the position of the openings 40 in the frame 30. In embodiments where the racket 10 is provided in more than one part the fixation material 70 may be inserted into a first part of the racket 10 and a second part of the racket 10 then put into position on the first part to form the enclosed space E. In the present embodiment the outer surface 35 is subsequently fixed to the remainder of the frame 30.

In embodiments the fixation material 70 may first be inserted into the frame 30 and the guiding members 50 subsequently inserted into the frame 30.

The guiding members 50 are now fixed in position. This may be done, for example, by activating, or curing, the fixation material 70 or otherwise setting the fixation material 70 in position. In embodiments the fixation material 70 may fix in position simply by cooling or being left to harden/solidify.

The strings 43 are now installed into the racket 10. This is completed by threading the string 43 through a first opening 42 which leads the string to exit through second opening 44. The string 43 is then threaded through a further first opening which leads the string 43 to exit through a further second opening. This process is repeated until the strung surface S is formed. In the present manufacturing process the racket 10 is formed by a moulding process. In embodiments, other, or additional, manufacturing processes may be used. For example, the manufacturing process may include the use of an inflatable device, or inflatable devices, which are inflated to define the enclosed space in a mould. The frame then may be formed using a mould by a moulding process. The inflatable device(s) may then be deflated and removed from the enclosed spaces.

In embodiments, soluble, meltable, expandable, or foam devices may be used in place of the inflatable devices. In further embodiments a mandrel may be used as part of the manufacturing process. For example, the handle 12 and/or the frame 30 may be formed using a mandrel.

Figure 7 shows a second embodiment in accordance with the present invention. Features which are in common with the first embodiment have been given the same reference numeral with the addition of 100. Those features will not be discussed again here. The main difference between the second embodiment and the first embodiment is that the hollow frame is filled with one or more different fixation materials to create one or respective regions in which the guiding members are fixed and which regions may have different properties with respective to each other. The guiding members that extend through the frame are thus encapsulated by the materials so as to be fixed in position whilst the string may still slide within the guiding members. Figure 7 shows a cross-sectional view of a frame 130. The frame 130 defines an enclosed space E. The enclosed space E is filled with a first fixation material to form a layer 170 and a second fixation material which forms layers 172, 174. The first layer 170 is sandwiched between second and third layers 172, 174. During manufacturing, the guiding members are first inserted into the openings as required so as to extend through the enclosed space E. The enclosed space E of frame 130 is then sequentially filled with the first and second fixation materials so as to form the layers 170, 172, 174. The guiding members 150 are thus encapsulated in the first fixation material of layer 170. Other layering combinations may be used without departing from the scope of the present invention. For example four, five or more layers may be used within the enclosed space E of alternating first and second fixation materials. Further, an additional third fixation material may be used in the enclosed space E without departing from the scope of the present invention.

In cross-section, the layer 172 has a bottom side 162 which abuts a top side 160 of the layer 170. The layer 174 has a top side 164 which abuts a bottom side 161 of the layer 170. The bottom side 162, top side 160, top side 164 and bottom side 161 in the present embodiment are generally linear. However, in embodiments the sides may be curvilinear or non-linear shaped, i.e. stepped, without departing from the scope of the present invention.

The layers 170, 172 174 extend across, and fill, the enclosed space E.

The manufacturing process for the second embodiment may be substantially the same as for the first embodiment. The key difference between the manufacturing processes is providing the layers 170, 172, 174 within the enclosed space E.

The manufacturing process involves the following steps: inserting the layer 174 at a bottom of the frame 130; inserting the layer 170 into the frame 130; and inserting the layer 172 into the frame 130. In the present embodiment the layer 174 is inserted first, then the layer 170 then the layer 172. In embodiments the layer 172, or the layer 170 may first be inserted. In embodiments the layer 170 may be inserted after the layers 172, 174.

In the second embodiment the guiding members 150 are inserted before the layers 170, 172, 174. In embodiments the guiding members 150 may be inserted after the layers 172, 174. In embodiments the guiding members 150 may be inserted after the layer 170.

Figure 8 shows a third embodiment in accordance with the present invention. Features which are in common with the first embodiment have been given the same reference numeral with the addition of 200. Those features will not be discussed again here.

Figure 8 shows a frame 230 which is similar to previously described embodiments but including an internal wall 280 which defines, with the frame 230, first and second enclosed spaces E1, E2, rather than a single enclosed space E. The internal wall 280 is annular and extends around the frame 230. The internal wall 280 is formed of first and second linear sides 282, 284 which are connected by an arcuate portion 294 which extends between them, in cross-section, The internal wall 280 is positioned generally centrally in the frame 230 and extends from a portion of the inwardly facing surface 232 towards an opposite portion of the surface 232 and terminates short thereof. The second enclosed space E2 is the space which exists between the outside of the wall 280 and the remainder of the internal surface of the frame 230. The first enclosed space E1 is thus surrounded by the second enclosed space E2.

In embodiments, the internal wall 280 may define a different shape.

In this embodiment, the space E1 is filled with a fixation material 270 and the guiding members 250 extend through the fixation material 270. The second enclosed space E2 is empty. In alternative embodiments the second enclosed space E2 may be filled with a second fixation material without departing from the scope of the present invention. In other embodiments the guiding member 250 may be positioned in the second enclosed space. In the present embodiment the first enclosed space E1 is smaller than the second enclosed space E2. However, in other embodiments, the first enclosed space E1 may be larger than the second enclosed space E2.

Figure 9 shows a fourth embodiment in accordance with the present invention. Features which are in common with the first embodiment have been given the same reference numeral with the addition of 300. Those features will not be discussed again here.

Figure 9 is similar to the embodiment shown in figure 7 with the exception of the second and third layers 172, 174 being omitted (i.e. the frame is empty in the spaces E2, E3) and including a first and second opposing walls 396, 398 that define a space in which the first fixation material is filled to form the layer 370.

The first and/or second internal walls 396, 398 are generally planar in the present embodiment and extend across the enclosed space defined by the frame 30. However, it should be appreciated that the first and second internal walls 396, 398 may be inclined / decline, form other shapes and/or be non- planar without departing from the scope of the present invention. For example, the first and/or second internal walls 396, 398 may be inclined at an angle to the plane P without departing from the scope of the present invention. In embodiments the first and second internal walls 396, 398 may be inclined at an angle with respect to each other.

Guiding member 350 is positioned in the first enclosed space E1 and the first enclosed space E1 defined by the walls 396, 398 is filled with a fixation material. The second and/or third enclosed space E2, E3 is empty. In alternative embodiments the second and/or third enclosed space E2, E3 may be filled with a second fixation material without departing from the scope of the present invention. In other embodiments the guiding member 350 may be positioned in the second or third enclosed space E2, E3 and the second or third enclosed space E2, E3 filled with a fixation material. The manufacturing processes for the third and fourth embodiments may be substantially the same as for the first embodiment. The key difference between the manufacturing processes is providing the internal walls 280, 396, 398 within the frame 230, 330. The manufacturing process involves inserting the internal walls 280, 396, 398 after the frame 230, 330 has been formed. In the third and fourth embodiments the internal walls 280, 396, 398 are fixed to an internal surface of the frame 230, 330. In embodiments the internal walls 280, 396, 398 may be integrally formed with the frame 230, 330.

The guiding members 250, 350 are inserted before the internal walls 280, 396, 398. This is advantageous in providing more space in which to form the correct channels between the openings 40. In embodiments the guiding members 250, 350 may be inserted after the internal walls 280, 396, 398. This may be advantageous for providing a more efficient moulding process for the frame 230, 330. The enclosed space E1 in the frames 230, 330 may be filled with fixation material after the internal walls 280, 396, 398 and/or the guiding members 250, 350 have been inserted. In embodiments the fixation material may be inserted before the internal walls 280, 396, 398 and/or the guiding members 250, 350. The enclosed spaces E2, E3 may also be filled with fixation material after the internal walls 280, 396, 398 and/or the guiding members 250, 350 have been inserted. When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components. The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Although certain example embodiments of the invention have been described, the scope of the appended claims is not intended to be limited solely to these embodiments. The claims are to be construed literally, purposively, and/or to encompass equivalents.