GB2147815A - A ball and manufacture thereof - Google Patents

Abstract

A ball comprising a cover formed from at least two cover-forming pieces (10, 11) surrounding a solid interior formed from a synthetic resin or other material which acts as an adhesive to hold said pieces together, and fibre reinforcing means (18) incorporated within the solid interior. The fibre reinforcement may be in the form of an element straddling the joint between the pieces 10, 11, and may be of glass, carbon, or Kevlar (RTM) fibre. The core is preferably of polyurethane either injected via a hole 16 between the assembled cover pieces, or placed in the cover pieces before they are brought together. <IMAGE>

Description

SPECIFICATION A ball and manufacture thereof This invention relates to balls, such as cricket balls, hockey balls, baseballs, rounders balls and the like, of the kind incorporating a core, and a cover, and to a method of manufacture of such balls.

According to one aspect of the present invention there is provided a ball comprising a cover formed from at least two cover-forming pieces, surrounding a solid interior formed from a synthetic resin which acts as an adhesive to hold said pieces together, and fibre-reinforcing means incorporated within the said solid interior.

According to a further aspect of the present invention there is provided a method of manufacturing a ball which comprises providing at least two cover-forming pieces, placing said pieces within a generally spherical cavity of a mould so as to line said cavity and injecting into the space between the pieces a synthetic resin or other material which will set after injection and also act as an adhesive to hold said pieces together, and wherein the synthetic resin incorporates a fibre reinforcement and/ or prior to injecting said synthetic resin a reinforcing element is located within the interior of the ball in a position in which said element straddles the join between the cover-forming pieces.

The cover of the ball may comprise two generally hemi-spherical cups and each cup may be formed from a single piece of material (such as leather, rubber or a synthetic resin material) in which case the ball may be referred to as a halved ball. Alternatively, each hemi-spherical cup may comprise two pieces of material which are stitched or otherwise connected together in which case the ball is referred to as a quartered bail. With either a halved ball or a quartered ball there may be provided a seam which extends around a diametral plane of the cover. Alternatively, the cover may be formed from two pieces of material which are each of generally figure-of-eight configuration.

If desired, each of the cover-forming pieces may be provided in a region adjacent the peripheral edges thereof with one or more rows of stitching, commonly referred to as "false stitching" because the stitching is not itself used to connect the coverforming pieces together.

Each of the aforesaid cover-forming pieces can be made of any convenient material. The synthetic resin material which is injected into the mould conveniently comprises a polyurethane material.

The invention will now be more particularly described, by way of example only, with reference to the accompanying drawing which is a sectional view of a mould used in carrying out one embodiment of a method in accordance with the invention.

Referring now to the drawing, a ball, typically a cricket ball, is made from a pair of generally hemispherical cups 10 and 11. Each cup may be formed of two separate pieces of material which are connected together in any convenient manner but preferably each cup is formed of a single piece of material. Any material suitable for the cover of a cricket ball may be used for the said cups, but preferably the cups are of leather. Each cup may include an outer layer lOa or Ila which is formed from a suitably shaped piece cut from a skin and afterwards "blocked" or shaped in a mould to provide the desired 9enerally hemi-spherical shape.

There may also be provided (as shown in the drawing) a lining lOb or llb which may be formed of leather or any other suitable material and which is secured by adhesive or in any other convenient manner to the interior of the adjacent outer layer IOa or lOb. Each of the two hemi-spherical cups thus formed is then provided in the region adjacent to its peripheral edge with one or more (desirably three) rows of stitching generally indicated by reference numeral 12 which extend around the circumference of the cup. Such stitching will project both from the exterior and the interior of the associated cup, the exterior projections forming the seam of the completed ball.The stitching 12 is commonly referred to as "false" stitching (and is conveniently carried out by machine) because the stitching itself is not used to connect the two hemispherical cups together although where a lining lOb and llb is provided as above described the stitching can be used to form an additional connection between the lining and the outer layer of each cup.

The two hemi-spherical cups 10 and 11 are then placed in a mould which includes an upper part 13 and a lower part 14, the bottom of the upper part registering in a recess formed in the top of the lower part 14. Furthermore at the upper end of the part 13 of the mould there is provided an aperture 15 which can be closed when required by means of a suitable plug (not shown). As shown in the drawing the aforesaid rows of stitching are arranged so that they lie in general horizontal planes and in this case a suitable small aperture indicated by reference numeral 16 is formed at the top of the cup 10 and through this aperture is injected by means of a suitable injector nozzle a synthetic resin or other material in order to fill the space enclosed by the cups 10 and 11 so as to form a core for the ball.The core forming material may comprise a synthetic resin material such as for example a self-curing polyurethane that foams slightly and which whilst curing will have adhesive properties.

Alternatively other thermo-setting or glue-like materials can be injected through the aperture 16 in order to fill the cavity between the cups 10 and 11.

In accordance with the invention, the fibre-reinforcing means may take the form of a fibre reinforcement such as glass fibres, carbon fibres or Kevlar fibres incorporated in the core-forming material. Alternatively, a reinforcing means can be included in the interior of the ball prior to injecting the synthetic resin. Such a reinforcing means must straddle the join between the two cover-forming pieces. Typically a strip formed of a glass fibre woven mat is formed into a circular configuration and is placed within the ball so that its outer face sits across the join between the two hemi-spherical cover-forming pieces. Alternatively individual fibre strands 18, typically glass fibre strands 12 mm in length, can be placed within the core thereby forming pieces which will be dispersed throughout the core on resin injection.

Although it is not essential, it may be desirable in some instances to coat the abutting edges of the cover-forming pieces with an adhesive, preferably an impact adhesive, prior to bringing the coverforming pieces together so as to ensure that the edges of the cover-forming pieces of the finished ball are strongly bound together.

Injection continues until the whole of said cavity is filled and until material starts to be ejected from said aperture 16. The hole 15 is then closed by the aforesaid plug until the material in said cavity sets whereafter the mould parts 13 and 14 can be separated and the completed ball removed for subsequent polishing or other operations. Alternatively, the plug can be dispensed with and the core-forming material can then be injected until it runs out of the hole 15, the excess material being trimmed off.

In an alternative arrangement the aforesaid rows of stitching can be arranged to extend in generally vertical planes so that injection on the material into the cavity between the cups 10 and 11 can be accomplished by prising apart the abutting edges of the two cups for a short length thereof beneath the hole 15 and material can then be injected through the space created between said abutting edges.

After injection has been completed the prised apart abutting edges can be allowed to recover so that they again abut each other and the hole 15 closed by means of the plug as before. Suitable clamps may also be provided to hold the two mould parts 13 and 14 together whilst curing takes place.

Whichever method of injecting the ball is adopted however the material that is injected will not only form a desired core but will also be sufficiently adhesive as to secure the two cups 10 and 11 together.

In an alternative method of manufacturing a ball in accordance with the invention, each of two cover-forming pieces is placed within a corresponding section of a mould defining a generally spherical cavity so as to line the cavity. Whilst the mould is kept open and the cover-forming pieces are kept apart the required amount of an expandable synthetic resin which will expand and set and which will adhere to the cover-forming pieces to hold them together, typically a polyurethane, is introduced into the interior of the lower cover-forming piece. The two cover-forming pieces are then brought together by closing the mould and are maintained in a spherical configuration while the synthetic resin expands and sets.

The present invention provides a relatively inexpensive method of making a cricket ball which has a cover formed of leather or other material and which may have a seam formed of machine made stitching. The relatively expensive method of using hand stitching to provide both the seam and a means for joining the two hemi-spherical cups together is therefore avoided. A ball made in this way also has the advantage that if the stitches are cut (as for example by being used on a hard playing surface) then the cover of the ball will not split.

The invention can also be used in the manufacture of balls without stitches for example stitchless balls which comprise a pair of hemi-spherical cups joined together by a cover as above-described. As a further alternative, the cover of a ball formed by a method in accordance with the invention may comprise two pieces which are of generally figureof-eight configuration disposed in an interlocking arrangement in which together they form a sphere and such a construction may be used for making inter alia stitchless hockey balls, rounders balls, or baseballs.

Claims (25)

1. A ball comprising a cover formed from at least two cover-forming pieces surrounding a solid interior formed from a synthetic resin which acts as an adhesive to hold said pieces together, and fibrereinforcing means incorporated within the said solid interior.

2. A ball as claimed in Claim 1, wherein there are two coverforming pieces which each comprise a hemi-spherical cup.

3. A ball as claimed in Claim 1, wherein there are two cover-forming pieces which are each of generally figure-of-eight configuration.

4. A ball as claimed in Claim 1, 2 or 3, wherein each of the cover-forming pieces is provided with a hemi-spherical lining.

5. A ball as claimed in any one of the preceding Claims, wherein each of the cover-forming pieces is provided around its periphery with one or more rows of stitches which project outwardly from the exterior of the cover-forming piece to form part of a seam of the completed ball.

6. A ball as claimed in any one of the preceding Claims, wherein the cover is of leather, of rubber or of a synthetic polymer.

7. A ball as claimed in any one of the preceding claims, wherein the said synthetic resin is a polyurethane.

8. A ball as claimed in any one of the preceding Claims, wherein the synthetic resin used to form the solid interior incorporates a fibre reinforcement thereby to provide fibre-reinforcing means.

9. A ball as claimed in Claim 8, wherein the fibre reinforcement is of glass fibre, carbon fibre, or Kevlar fibre.

10. A ball as claimed in any one of Claims 1 to 7, wherein the fibre reinforcing means is a reinforcing element located internally of the ball so as to straddle the join of the cover-forming pieces.

11. A ball as claimed in Claim 10, wherein the reinforcing element comprises a strip of fibre mat coiled into a circular configuration.

12. A method of manufacturing a ball which comprises providing at least two cover-forming pieces, placing said pieces within a generally spherical cavity of a mould so as to line said cavity and injecting into the space between the pieces a synthetic resin or other material which will set after injection and also act as an adhesive to hold said pieces together and wherein the synthetic resin incorporates a fibre reinforcement, and/or prior to injecting said synthetic resin a reinforcing element is located within the interior of the ball in a position in which said element straddles the join between the cover-forming pieces, and/or prior to injecting the resin reinforcing fibre strands are placed within the core for subsequent dispersion throughout the core when the resin is injected.

13. A method as claimed in Claim 12, wherein there are two cover-forming pieces which each comprise a hemi-spherical cup.

14. A method as claimed in Claim 12, wherein there are two cover-forming pieces which are each of generally figure-of-eight configuration.

15. A method as claimed in Claim 12, 13 or 14, wherein each of the cover-forming pieces is provided with a hemi-spherical lining.

16. A method as claimed in any one of Claims 12 to 15, wherein each of the cover-forming pieces is provided around its periphery with one or more rows of stitches which project outwardly from the exterior of the cover-forming piece to form part of a seam of the completed ball.

17. A method as claimed in any one of Claims 12 to 16, wherein said synthetic resin or other material is injected into the space between the coverforming pieces through an aperture formed in one of the cover-forming pieces.

18. A method as claimed in any one of Claims 12 to 16, wherein said synthetic resin or other material is injected into the space between the coverforming pieces through a small aperture formed by prising apart the abutting edges of the pieces along a small part of the length thereof.

19. A method as claimed in any one of Claims 12 to 18, wherein the said synthetic resin is a polyurethane.

20. A method as claimed in any one of Claims 12 to 19, wherein the fibre reinforcement is of glass fibre, carbon fibre or Kevlar fibre.

21. A method as claimed in any one of Claims 12 to 20, wherein the reinforcing means comprises a strip of fibre mat coiled into a circular configuration.

22. A method as claimed in any one of Claims 12 to 21, wherein the abutting edges of the coverforming pieces are coated with an adhesive prior to bringing the cover-forming pieces together.

23. A method of manufacturing a ball, which method comprises providing two cover-forming pieces, placing each of said pieces in corresponding sections of a mould defining a generally spherical cavity so as to line said cavity, introducing into the interior of the lower cover-forming piece with the mould in an open condition the required amount of an expandable synthetic resin which will expand and set and which will adhere to said cover-forming pieces to hold them together, and bringing the two cover-forming pieces together by closing the mould thereby to maintain the coverforming pieces in a spherical configuration while the synthetic resin expands and sets.

24. A ball as claimed in Claim 1 substantially as hereinbefore described with reference to the accompanying drawing.

25. A method as claimed in Claim 12 substantially as hereinbefore described with reference to the accompanying drawing.