ZA200205593B

ZA200205593B - A sports bat made of synthetic materials.

Info

Publication number: ZA200205593B
Application number: ZA200205593A
Authority: ZA
Inventors: Daryl Ludewig; Dennis Kappetijn; Colin Groom; Stefano Bazinni
Original assignee: Cricket Bat Company Proprietar
Priority date: 1999-12-14
Filing date: 2002-07-12
Publication date: 2003-07-09

Description

A SPORTS BAT MADE OF SYNTHETIC MATERIALS

INTRODUCTION

This invention relates to a sports bat, in particular, but not exclusively, a cricket bat or a baseball bat, in which the bat is made substantially entirely of synthetic materials by which term is meant materials not occurring in nature. It is to be noted that in this specification the term sports bat is intended to include any solid, ball striking stick or bat and thus includes such items as hockey sticks and the like.

BACKGROUND TO THE INVENTION

Sports bats, and more particularly cricket bats and baseball bats are traditionally made of rather special types of wood. Such wood is becoming increasingly scarce and, accordingly, costly. Also, wood does not necessarily provide the most advantageous characteristics bearing in mind the object to be achieved by the bat. Applicant therefore considers it desirable that altemative materials of production be effectively employed.

Numerous different proposals have been made for the construction of baseball and other sports bats from synthetic, or at least non-wood materials. Many of these have included a tubular core which may be filled with a foam plastic, usually polyurethane, material which is resilient and light in weight. The tubular ; core is often of aluminium or other suitable metal material, although in some cases the tube may be made of a plastics material. In many instances the outer surface, particularly in the case of baseball bats, is made of a metal which renders the outer surface extremely hard. ) At least many of the various arrangements described in prior art may operate effectively when applied to baseball bats, but most of the prior proposals are considered by applicant to be inappropriate when applied to a cricket bat.

OBJECT OF THE INVENTION

It is an object of this invention to provide an improved sports bat made at least predominantly of synthetic materials in which the construction is well suited to a cricket bat but may also be appropriate, in at least some forms of the invention, to a baseball bat or other sports bat.

SUMMARY OF THE INVENTION

In accordance with this invention there is provided a sports bat having a handle and a ball striking portion and comprising a spine in the form of an elongate fibre reinforced polymeric member extending along substantially the entire length of the bat and having a handle end portion and a ball striking end portion, a polymeric core moulded on to spine and extending over at least the length of the ball striking portion of the bat, the core having an outer region which is fibre reinforced over at least the entire ball striking region of the bat, and a polymeric outer cover on at least the ball striking portion of the bat wherein the outer cover is resiliently deformable to an extent enabling it to distribute the force of an impact on the cover over an area of the fibre reinforced core.

Further features of the invention provide for the sports bat to be a cricket bat; for the spine to form the handle of the cricket bat with the handle portion of the spine being covered by one or more layers of material defining a grip, and optionally, a shock absorbing layer which may also cover the entire length of the . spine if required; for the spine to be defined by a pultruded or extruded fibre reinforced resin . material, for example, a glass fibre reinforced polyester or epoxy resin; for the polymeric core to be of a suitable polyurethane material, in particular a polyether polyol based structural polyurethane foam having a density of from 150 to 800 kilograms per cubic metre and preferably from 250 to 500; and for the outer cover to be of a similar polyurethane material but having a density of from 300 to 800 kilograms per cubic metre and preferably from 400 to 600.

Still further features of the invention provide for the spine to be shaped to a slightly bowed configuration along its length so that its axis passes along the normal path of curvature of a cricket bat blade; for the spine to be shaped at its end associated with the striking end of the bat to a divergent shape; for a fibre reinforced prefabricated insert to be moulded into the bat adjacent its striking surface; for the core to have a recess in the rear thereof opposite the sweet spot on the striking surface of the bat and wherein the recess is generally filled with the material of which the outer cover is made during moulding of the cover thereon although it may be filled with a different material, for the front of the core to also have a recess but that in this case filled with a material chosen to provide required characteristics of that particular region of the bat. and for the end of the blade remote from the handle to have a hard wearing insert therein optionally attached to the spine. } The invention also provides a method of producing a sports bat as defined above comprising forming an envelope of fibrous reinforcing around a spine in the form ; of an elongate pultruded or extruded fibre reinforced resin member; moulding a polymeric core around the spine in a suitable mould and in a manner such that the fibrous reinforcing is urged by the flowing polymeric material towards the ) surface of the mould so as to cause the reinforcing material to become embedded in the polymeric material in an outer region thereof at or adjacent the . outer surface of the core, and subsequently moulding an outer cover of a polymeric material on to the core in a separate mould.

In carrying out in the method defined above the envelope of fibrous reinforcing could be loose and flexible and could be pre-formed simply by rolling a stitched stranded mat or a woven glass fabric or roving loosely around the spine.

Alternatively, the envelope could be formed as a pre-pressed and moulded reinforcing sheet usually in two halves possibly hinged together along one side.

The pre-fabricated reinforcing sheet could be held in its formed shape by a small amount of cured or semi-cured resin; or it could be in the form of a glass mat thermoplastic; a fully impregnated transfer moulding; a buik moulding compound or a thermosetting glass mat.

In the event that an insert is moulded into the striking portion of the bat adjacent its striking surface that insert could be of shallow channel shape in cross-section and could have integral or separate saddles for supporting the spine horizontally in a mould during the production process. Alternatively, the spine may have recesses pressed into it, for example when the spine is semi-cured and at the same time the end of the spine remote from the handle could be pressed to form a divergent and flattened formation. The recesses could serve to receive locating pins in the mould to hold the spine in position whilst the core is moulded on to it.

At the same time as the spine is pressed in a semi-cured condition, the usual slightly bowed shape of a cricket bat could be applied to it. When the cover is moulded onto the core recesses, locating pins can be employed to locate it in the second mould. . It is to be noted that the fibres used as a reinforcing medium in this invention could be of many different types and could even be natural fibres or the more sophisticated carbon and Kevier fibres. From an economic point of view glass } fibres will undoubtedly always be one possible choice. : In order that the above and other features of the invention may be more fully understood a preferred embodiment of the invention and a number of variations thereof will now be described with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. is a sectional front elevation of a cricket bat made according to the invention;

FIG2 is a sectional side view thereof,

FIG3 is a cross-section taken through a ball striking portion or blade of the cricket bat;

FIG .4 is a view similar to Figure 3 but illustrating a modification in the form of an insert adjacent the striking surface of the bat; and

FIG.5 is a sectional elevation similar to Figure 1 only of the lower portion of the bat and illustrating a further variation of the embodiment of the invention.

DETAILED DESCTRIPTION OF THE DRAWINGS

In the embodiment of the invention illustrated in Figures 1 to 3, a cricket bat “ (generally indicated by numeral 1) has a pultruded glass fibre reinforced . 35 polyester resin spine (2) extending along substantially the entire length of the bat and having a handle portion (3) and a striking face portion (4). The pultruded } spine is produced by pressing a partly cured pultrusion in a suitable die to modify the shape of the generally circular cross-sectioned member to provide a flattened » and divergent portion (5) at the toe end of the spine and a series of recesses (6) along the length of the spine at diametrically opposed positions. In the pressing process a slight bow is applied to the length of the spine so that axis follows the normal curve of the front face of a cricket bat. At the same time any other formations required such as locking formations adapted to mechanically lock the core to the spine may also be pressed into the semi-cured spine. A terminal headed formation (7) may also be formed at the free end of the handle portion (3) of the spine. : Preparatory to moulding a core (8) on to the spine, the spine is cleaned and, if necessary, sand blasted in order to ensure a proper bond, at least of a mechanical nature, between the core and spine. tis also possible at this stage to spray or otherwise coat the spine with a bonding agent to promote chemical bonding of the core to the spine. The core is then enveloped in an envelope (9) of reinforcing material which is conveniently a stitched glass fibre mat or woven fabric or roving which loosely encircles the spine over the length thereof corresponding to the striking part of the bat. The spine is then supported in a mould (not shown) by means of locating pins which engage in the recesses (6) to hold the core in a suitably spaced position relative to the inner surface of the mouid.

The core (8) of polymeric materials is then moulded on to the spine over at least the region corresponding to the striking portion of the bat but possibly also as a layer over the handie. The polymeric material employed must exhibit some } resilience but is substantially rigid when cured. A convenient type of material is a structural polyurethane foam based on a polyether polyol and MDI and having , a density of from 250 to 500 kilograms per cubic metre. Introduction of the polymeric material into the mould is effected in a manner such that flow of the material prior to curing thereof urges the reinforcing fibres outwardly so that they ) become embedded in the polymeric material of which the core is made at or towards its outer surface.

The partly made bat is then located in a second mould in order to form an outer cover (10) over the entire striking part of the bat, and, in one variation, also over the handle as illustrated and indicated by numeral (11). The polymeric material from which the cover is made is conveniently a similar foamed structural polyurethane to that used for the core except that the density is somewhat greater and generally between 400 and 600 kilograms per cubic metre. The thickness of the outer cover is conveniently about 4 mm.

It will be understood that, in use, the cover serves to distribute any impact of a ball hitting it over a larger area of the glass reinforced core which prevents the core from becoming damaged as experience has shown would be the case without the outer cover. Also, the divergent portion (5) of the spine will prevent the core from rotating on the spine should there be any tendency for it to do so.

Numerous variations and modifications may be made to the embodiment of the invention described above without departing from the scope hereof. Thus, as indicated in Figure 4. a prefabricated insert (11) of a shallow channel shape could be moulded into the bat so that it lies adjacent the striking surface (12). In such a case the insert may have either integral or separate supports (13) in the form of saddles to support the spine (14) in a horizontal position during the moulding of the core on to it. The insert could be a prefabricated fiberglass or other fibre reinforced member which could extend over only the sweet spot or could extend over the entire height of the striking part of the bat, or any other part of the length thereof. Similarly the insert could extend over the entire width of the striking face ’ or a narrower portion thereof.

In order to protect the free end (15) of the blade (16) of the bat, and as illustrated . in Figure 5, a hardened insert (17) may be included in the bat at the toe so that wear and tear consequent on the end of the bat being regularly tapped or struck : on the pitched is accepted. This insert (17) could be attached to the adjacent end (18) of the spine.

Figure 5 also illustrates a variation in which an annular cavity (20) is moulded into the rear or the core opposite the sweet spot so as to become filled with the same material (21) as the cover (22) during the moulding of the latter. It may however be filled with other material. In any event the purpose of this is to enlarge the sweet spot.

Another cavity (not shown) could be located in the front region of the core of the bat and could be filled with a material chosen to provide particular characteristics to a region of the bat. Locating the cavity in different positions could cause different weightings of the bats and different locations of the center of gravity.

Also, different materials and different locations of this recess could be used to render different regions of the bat more or less lively according to requirements.

Thus, for example, an upper region of the striking part of the bat, could be rendered less lively for the purposes of the blocking whilst the striking part of the bat in the region of the sweet spot could be rendered more lively.

It is to be noted that the striking face of the bat is bowed slightly outwardly in cross-section as shown clearly in Figure 3. In this manner a spring effect is achieved within the surface by the impact of a ball and most particularly with a ball that strikes the face centrally. . Numerous other variations are possible in the scope of this invention. In particular the polymeric materials employed could be varied widely as could the ; type of reinforcing fibres used.

Claims

1. A sports bat having a handle and a ball striking portion and comprising a . spine in the form of an elongate fibre reinforced polymeric member extending along substantially the entire length of the bat and having a handle end portion and a ball striking end portion, a polymeric core moulded on to spine and extending over at least the length of the ball striking portion of the bat, the core having an outer region which is fibre reinforced over at least the entire ball striking region of the bat, and a polymeric outer cover on at least the ball striking portion of the bat wherein the outer cover is resiliently deformable to an extent enabling it to distribute the force of an impact on the cover over an area of the fibre reinforced core.

2. A sports bat as claimed in claim 1 which is a cricket bat.

3. A sports bat as claimed in claim 2 in which the spine forms the handle of the cricket bat with the handle portion of the spine being covered by one or more layers of material defining a grip.

4 A sports bat as claimed in claim 3 in which the handle portion of the spine is also covered by a shock absorbing layer.

5. A sports bat as claimed in claim 4 in which the shock absorbing layer covers the entire length of the spine.

6. A sports bat as claimed in any one of the preceding claims in which the spine is defined by a pultruded or extruded fibre reinforced resin material.

T. A sports bat as claimed in claim 6 in which the pultruded or extruded } fibre reinforced resin material is a glass fibre reinforced polyester or epoxy resin. :

8. A sports bat as claimed in any one of the preceding claims in which the polymeric core is of a polyurethane material.

9. A sports bat as claimed in claim 8 in which the polymeric core is a polyether polyol based structural polyurethane foam having a density of from 150 to 800 kilograms per cubic metre.

10. A sports bat as claimed in claim 9 in which the density of the polyol based structural polyurethane foam is from 250 to 500 kilograms per cubic metre.

11. A sports bat as claimed in either one of claim s 9 or 10 in which the outer cover is of a similar polyurethane material with a density of from 300 to 800 kilograms per cubic metre .

12. A sports bat as claimed in claim 11 in which the polyurethane material has a density of from 400 to 600 kilograms per cubic metre.

13. A sports bat as claimed in any one of claims 2 to 12 in which the spine is shaped to a slightly bowed configuration along its length so that its axis passes along the normal path of curvature of a cricket bat blade.

14. A sports bat as claimed in any one of claims 2 to 13 in which the spine is shaped at its end associated with the striking end of the bat to a . divergent shape.

1b. A sports bat as claimed in any one of claims 2 to 14 in which a fibre ) reinforced prefabricated insert is moulded into the bat adjacent its striking surface.

16. A sports bat as claimed in any one of the preceding claims 1 which the core has a recess in the rear thereof opposite the sweet spot on the striking surface of the bat and wherein the recess is filled with the material of which the outer cover is made.

17. A sports bat as claimed in any one of the preceding claims in which the front of the core has a recess filled with a material chosen to provide required characteristics of that particular region of the bat.

18. A sports bat as claimed in any one of the preceding claims in which the end of the blade remote from the handle has a hard wearing insert therein.

19. A sports bat as claimed in claim 18 in which the hard wearing insert is attached to the spine.

20. A method of producing a sports bat as defined above comprising forming an envelope of fibrous reinforcing around the spine in the form of an elongate pultruded or extruded fibre reinforced resin member, moulding a polymeric core around the spine in a suitable mould and in a manner such that the fibrous reinforcing is urged by the flowing polymeric material towards the surface of the mould so as to cause the reinforcing material to become embedded in the polymeric material in an , outer region thereof at or adjacent the outer surface of the core, and _ subsequently moulding an outer cover of a polymeric material on to the 4 core in a separate mould.

21. A method as claimed in claim 20 in which the envelope of fibrous , reinforcing is loose and flexible. u

22. A method as claimed in claim 21 in which the envelope of fibrous reinforcing is pre-formed by rolling a stitched stranded mat or a woven glass fabric or roving loosely around the spine.

23. A method as claimed in ctaim 21 in which the envelope is formed as a pre-pressed and moulded reinforcing sheet.

24. A method as claimed in claim 23 in which the moulded reinforcing sheet is formed in two halves.

25. A method as claimed in claim 24 in which the two halves are hinged.

26. A method as claimed in either one of claims 23 or 24 in which pre- fabricated reinforcing sheet is held in its formed shape by a small amount of cured or semi-cured resin.

27. A method as claimed in either one of claims 23 or 24 in which the prefabricated reinforcing sheet is any one of a glass mat thermoplastic; a fully impregnated transfer moulding; a bulk moulding compound or a thermosetting glass mat.

28. A method as claimed in any one of claims 20 to 27 in which an insert is moulded into the striking portion of the bat adjacent its striking surface. )

29. A method as claimed in claim 28 in which the insert is of shallow channel shape in cross-section. d

30. A method as claimed in either one of claims 28 or 29 in which the insert has integral or separate saddles for supporting the spine horizontally in a mould during the production process.

31. A method as claimed in claim 28 in which the spine has recesses pressed into it.

32. A method as claimed in claim 31 in which the spine has recesses pressed into it when the spine is semi-cured and at the same time the end of the spine remote from the handle is pressed to form a divergent and flattened formation.

33. A method as claimed in either one of claims 31 or 32 in which the recesses serve to receive locating pins in the mould to hold the spine in position whilst the core is moulded on to it.

34. A method as claimed in either one of claims 32 or 33 in which at the same time as the spine is pressed in a semi-cured condition, a usual slightly bowed shape of a cricket bat is applied to it.

35. A method as claimed in any one of claims 31 to 34 in which locating pins can be employed to locate the cover in the second mould when it is moulded onto the core

36. A sports bat, substantially as herein described with reference to an as illustrated in Figure 1 and 2, together with any one of Figures 3 to &.

37. A method of producing a sports bat, substantially as herein described with reference to Figures 1 and 2, together with any one of Figures 3 to