Conventional cricket bats are made virtually entirely of wood. It is however recognised that conventional wooden bats have a limited"sweet spot", i. e. zone of the ball-striking surface of the bat where there is optimal transfer of energy to a ball struck by the bat. It is also recognised that conventional wooden bats have a tendency to transmit undesirable and unpleasant shock forces to the hands of the batsman if a ball should be struck outside the sweet spot.

Given the inherent consistency of timber, it is also recognised that a disadvantage of conventional wooden bats are prone to unpredictable breakage.

SUMMARY OF THE INVENTION According to the invention there is provided a ball-striking bat comprising a handle portion and a ball striking portion connected to the handle portion, a plurality of flexible rods extending lengthwise and continuously through the handle and ball striking portions, the rods being spaced apart from one another to form an open skeletal structure in the ball striking portion, a reinforcing, porous sleeve located about the skeletal structure in the ball striking portion, and a moulded polymeric body filling and embedding the skeletal structure and sleeve in the ball striking portion. Similarly the handle portion of the bat comprises a moulded polymeric body in which the rods in the handle portion are embedded.

Other features of the invention will be apparent from the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings in which: Figure 1 shows a face view of a cricket bat according to this invention; Figure 2 shows a side view of the cricket bat; Figure 3 shows a perspective view of the internal reinforcing components of the bat; Figure 4 shows a cross-section taken at the line 4-4 in Figure 1; and Figure 5 shows a cross-section taken at the line 5-5 in Figure 1.

DESCRIPTION OF PREFERRED EMBODIMENTS The cricket bat 10 seen in Figures 1 and 2 has a conventional external shape. It has a slender handle portion 12 where it is gripped by a batsman and a ball striking portion or blade 14. The handle portion 12 has a round cross-section and the central region 16 thereof has a slightly smaller diameter than the end regions 18 and 20 thereof. The ball striking portion 14 has a generally triangular cross-section with a front, slightly curved ball striking surface 22. As conventional and as illustrated in Figure 2 the thickness of the ball striking portion, measured in a direction normal to the ball striking surface 22, varies over the length of the ball striking region.

The internal reinforcing structure of the bat is illustrated in Figure 3. It includes a plurality of pultruded, glass fibre reinforced polymeric rods 24, in this case of 4mm diameter. In the ball striking portion of the bat, the rods 24 are generally parallel to one another and are spaced apart to form an open skeletal structure designated by the numeral 26. In this portion of the bat, the rods are held in their spaced relationship by spacer members 28.1,28.2 and 28.3 located at a distance from one another. The spacer members, which may for instance be provided by thin metal or plastics plates, serve to maintain the required spacing of the rods at different positions along the length of the ball striking portion. In some cases, the rods 24 pass through holes in the spacer members and in other cases are located in cut-outs at the edges of the spacer members.

The spacing and location of the holes and cut-outs in the spacer members in the handle portion 14 varies from one member to the next to vary the positioning and spacing of the rods. At a position towards the upper end of the ball striking portion 14, a spacer member 28.4 causes the rods 24 to converge towards one another. In a region between the spacer member 28.4 and a further spacer member 28. 5 some rods are twisted relative to others as illustrated. Thereafter, between the spacer member 28.5 and the final spacer member 28.6, which are similar to one another, the rods are generally parallel to one another and lie in a compact circular array as will be apparent from Figure 5.

The numeral 30 indicates a porous reinforcing sleeve which is slipped over the skeletal structure 26 in the ball striking portion 14 of the bat. In this embodiment, the sleeve 30 is a composite, braided biaxial sleeve of Kevlar and carbon fibres. Sleeves of this type are produced by A&P Technology Inc of Covington, Kentucky, USA, a suitable example being that marketed under the designation Cobrasox V81 L58L200X. The diameter of the sleeve is selected such that it can be slipped as a snug fit over the structure 26.

The assembly of skeletal structure 26 and sleeve 30 is placed in a mould where it is encapsulated, in a moulding operation, in a body 32 of low density, rigid structural polyurethane foam, typically one having a density in the range 200kg~3 to 400kgm-3, preferably about 300kg~3. The body 32 entirely fills the central region between the rods 24 and embeds the sleeve 30 to some depth. It will be noted that the spacer members have central apertures 36 to facilitate the formation of a continuous moulded body. In addition, the porosity of the sleeve 30 permits the formation of a continuous moulded body. The moulded body 32 extends lengthwise past the ends of the rods 24 to the toe of the bat.

The mould is such that the moulded body 32 does not encapsulate the rods 24 in the handle portion 12. It terminates at the shoulder 38 of the bat and is formed with an arcuate rebate 40 as indicated by the dotted line in Figure 1.

A skin 42 of a polyurethane foam which is less rigid than that of the body 32 is then moulded over the body to provide the final surface of the ball striking portion of the bat. The skin 42 will typically have a thickness in the range 3mm to 4mm and will be of an elastomeric grade polyurethane foam, typically one having a density in the range 400kgm-3 to 600kg-3.

In some cases where a lower cost bat is required, it is possible to omit the skin 42. In such cases, the body 32 will itself form the final surface of the ball striking portion of the bat.

The handle portion 12 of the bat is separately moulded. In this case, the projecting portions of the rods 24, in their close circular array, are placed in a mould and are encapsulated in a moulded body 44 of elastomeric polyurethane. The polyurethane which is used typically produces a body 44 having a Shore A hardness of about 70. At its lower end the body 44 fills the rebate 40 and blends smoothly with the body 32.

As shown partially in Figure 1, a soft tubular grip 46 of rubber or the like may be located over the handle portion to improve the integrity of a batsman's grip on the handle portion.

Initial testing has shown that the bat 10 has a large"sweet spot". It is believed that this is primarily attributable to the use of the interior skeletal structure 26 which leads to an efficient transfer of energy from the bat to a ball which is struck thereby, even if the ball should be struck at a position away from the centre of gravity of the ball striking portion. Particularly when the skin 42 is included, it has been found that the bat gives a soft feel when a ball is struck.

The initial tests have also shown that the bat 10 can have a reduced tendency, compared to conventional wooden bats, to transmit shock forces to the hands of a batsman. It is believed that this can be attributed both to the use of the structure 26 and to the fact that the body 44 is moulded separately from the body 32 and is of an elastomeric grade of polyurethane.

In a modified bat (not shown) intended for use in training, the body 44 may be moulded such that its outer surface has a shape which will encourage the batsman to take up a proper grip on the bat. There may, for instance, be finger and/or hand indentations corresponding to recommended hand and finger positions.

In another embodiment of the invention, the porous reinforcing sleeve 30 is of glass rovings arranged in a biaxial format. Whereas in the embodiment described above, the sleeve 30 is tubular in shape, in this case it will typically be provided in form of a rectangular sheet of the glass roving material which is merely wrapped about the structure 26 prior to moulding.

The moulding procedure is then similar to that described above, with the central region of the wrapped structure initially being filled and the sleeve slightly embedded with low density, rigid structural polyurethane foam and a less rigid, elastomeric grade polyurethane skin subsequently being moulded externally to provide the final surface.

It is also within the scope of the invention for the handle portion 12 to moulded at the same time as the ball striking portion 14, so that the entire bat is of one-piece construction. In this case, a two stage moulding procedure may again be used to create a relatively rigid core region with an external, elastomeric skin, as described previously.

Figure 4 illustrates an array of reinforcing rods 24, in the ball striking region, in which there are nine rods close to the ball striking surface of the bat and five rods close to the rear surface of the bat. In another arrangement, there may be an equal number of rods at the ball striking surface and at the rear surface, with the rods at the ball striking and rear surfaces being in opposing pairs, i. e. with each rod at the ball striking surface being directly opposite a rod at the rear surface. There may for instance be five rods at each surface. Experimentation has shown that this configuration leads to a particularly strong bat structure.

Apart from the large"sweet"spot and reduction in shock transmission, bats according to the invention are found to be extremely strong and resistant to breakage.