GB2183489A

GB2183489A - Quartered balls and manufacture thereof

Info

Publication number: GB2183489A
Application number: GB08529330A
Authority: GB
Inventors: Royston Noel Thomas; John Villiers Reader
Original assignee: Reader & Co Ltd Alfred
Current assignee: Reader & Co Ltd Alfred
Priority date: 1985-11-28
Filing date: 1985-11-28
Publication date: 1987-06-10
Also published as: GB2183489B; GB8529330D0

Abstract

A ball e.g. for cricket comprises a cover which is formed from two substantially hemispherical cover-forming pieces 18, 20, each cover-forming piece comprising a single piece of material having an elongate slit 4 through the thickness thereof, the slit having been closed by stitches which are disposed on one side only of the material, and a solid core around which the two cover-forming pieces are secured so that each closed slit extends around a major part of the respective hemispherical cover-forming piece but stops short of the seam 25 between the two cover-forming pieces and so that the stitches which close each slit are concealed within the ball. <IMAGE>

Description

SPECIFICATION Quartered Balls and Manufacture Thereof The present invention relates to a method for making a quartered ball, such as a cricket ball, and to a quartered ball.

A known quartered ball, e.g. a cricket ball, comprises a cover which surrounds a solid core. The cover comprises two hemispherical cups which are stitched together around their abutting peripheral circumferential edges to form a stitched seam. Each hemispherical cup comprises two pieces of material e.g. leather which are stitched together by stitches which pass from one side of one piece of material, between the faces of the piece of material, across the abutting edges of the two pieces of material, and between the faces of the other piece of material and thence out of the other piece of material on the same side as the side of entry of the stitch. When so stitched, each hemispherical cup has an internal stitched side which has two visible rows of stiches which run parallel to the stitched seam and an external unstitched side which is free of stitches.In the cricket ball manufacturing art, this sewing of two pieces of leather to form a half cover is well known as closing. Each hemispherical cup is then shaped by blocking in a hydraulic press to the desired hemispherical shape. The two cups are then sewn around a solid core. In the resultant ball, the two stitch-free seams are each at right angles both to the circumferential stitched seam between the two cups and to each other. The "quarters" of the quartered ball are the four regions which are defined by the three seams.

The known quartered balls suffer from the disadvantage that the stitches of the circumferential stitched seam must coincide with the stitches of the seams between the two pieces of each cup since those latter stitched seams extend down to the circumferential seam in order that no splits can occur in the ball between the two pieces of material which form each half-cover. This over stitching can result in interference between the two sets of stitches which can cause unsightly buiging of the material of the cover or non-uniformity of stitching.

In addition, the gap which is between the abutting edges of the two quarter pieces can interfere with the stitches of the seam.

The present invention relates to a quartered bail which does not require such overstitching.

Accordingly, the present invention provides a method for making a ball, the method comprising the steps of: (a) providing two substantially hemispherical cover-forming pieces for the bail, each coverforming piece comprising a single piece of material having an elongate slit through the thickness thereof, the slit having been closed by stitches which are disposed on one side only of the material; and (b) securing the two cover-forming pieces around a solid core for the ball so that each closed slit extends around a major part of the respective hemispherical cover-forming piece but stops short of the seam between the two cover-forming pieces and so that the stitches which close each slit are concealed within the ball.

The present invention further provides a ball comprising a cover which is formed from two substantially hemispherical cover-forming pieces, each cover-forming piece comprising a single piece of material having an elongate slit through the thickness thereof, the slit having been closed by stitches which are disposed on one side only of the material, and a solid core around which the two cover-forming pieces are secured so that each closed slit extends around a major part of the respective hemispherical cover-forming piece but stops short of the seam between the two coverforming pieces and so that the stitches which close each slit are concealed within the ball.

Embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings, in which: Figure lisa plan view of a leather disc to form a half-cover of a ball when made in accordance with the invention; Figure 2 is a section on line A-A of Figure 1; Figure 3 is a side view of a cricket ball when made in accordance with the invention and incorporating the disc of Figure 1; and Figure 4 is a schematic sectional view of a mould containing a cover for use in making a ball in accordance with a further embodiment of the invention.

Referring to Figures 1 and 2, a flat disc 2 of leather which is to form a half-cover of a cricket ball has a straight slit 4 cut therein through the thickness of the leather. If desired, the leather may be square or otherwise shaped instead of being a disc. The slit 4 extends along part, typically about 70%, of a diametrical line across the disc 2 and is centred on the centre of the disc. Typically, the slit 4 is about 7.5 cm long in a disc 2 which is about 12 cm in diameter for use in making a ball having a diameter of about 7 cm. One surface of the leather, which is to be the inner surface of the half-cover, is depicted in Figure 1. The slit 4 is sewn together by stitching thread, which may be synthetic or natural, through the leather, the thread is being visible as two rows 6,8 of stitches which are parallel to and on opposing sides of the slit 4.The slit 4 is sewn either by hand or by machine. The stitches pass through the body of the leather disc 2 between the two faces of the disc and across the slit 4 so as to stitch together the two sides of the slit 4. Each stitch consists of a visible portion 10 which is parallel to the slit 4 and an invisible portion 12, which is shown in Figure 2, which is at right angles to and extends across the slit 4. At the end of each row 6, 8 of stitches is an end portion of twine 14. The stitches are visible only on the other surface of the leather disc. The other surface of the leather disc, which is to be the outer surface of the half-cover, merely has the closed slit extending thereacross. When the stitching is completed, the slit is firmly closed. The number of stitches may be varied as desired, but typically is from 6 to 25 depending on the subsequent manufacture of the ball.

Referring to Figure 3, there is shown a cricket ball 16 made in accordance with the present invention.

The cricket ball 16 comprises two half-covers 18,20, which have been formed from two discs 2, which have been sewn together around a solid core, for example a conventional cricket ball core formed from alternating layers of cork and worsted. The half-covers 18, 20 are formed by shaping or blocking the discs 2 in a hemispherical mould under pressure so as to deform the discs 2 into a hemispherical shape. If desired, a lining of leather or ieatherboard or other material may be provided for each of the half-covers 18, 20, the lining being adhered to the inside of the respective half-cover by, for example, a solvent-based adhesive or a hot melt adhesive.The hemispherical half-covers 18, 20 are then placed around the solid core and sewn together by two rows of stitches 21 to form a stitched seam 23 in known manner either by hand or by machine. The two half-covers are positioned relative to each other so that the two slits 4 are at 90 to each other.

The two rows of "false" stitches 25 may also be provided around the peripheral edge of each half cover 18,20 so that the stitched seam 23 has 6 rows of stitches. When the two half-covers 18, 20 are sewn together around the solid core, there are preferably from 14 to 20 stitches securing each slit 4 together when the diameter of the ball is about 7 cm and the slits are each from 6.5 to 9.5 cm long.

In the resultant cricket ball, since the stitches 6,8 which are employed to stitch the two slits 4 together do not extend as far as the circumferential edge of the discs 2, then those stitches 6, 8 are not overstitched by the stitches 21, 25 which are used for circumferential stitched seam 23. This ensures an evenly stitched seam 23.

In addition, the cricket balls of the present invention are cheaper to produce than conventional quartered cricket balls since the time required to stitch the slit 4 is less than that required to stitch two pieces of leather together due to the reduced length which has to be stitched. Also, in the present invention the stitching of the slit is carried out along a straight line whereas in conventional cricket balls the two pieces of leather are stitched together along a curved line so that the resultant half-cover is in the form of a cup. It is quicker and easier to stitch along a straight line, as in the present invention, rather than along a curved line. Furthermore, since each half-cover is made from a single piece of leather, rather than two pieces of leather as in the prior art, this ensures uniform thickness, structure and colour of the leather for each half-cover.

An alternative method of making a cricket ball in accordance with the invention is now described with reference to Figure 4. The described method is disclosed in my copending British Patent Application entitled "Balls and Manufacture Thereof" filed 28th November 1985. The resultant ball is similar in appearance to that shown in Figure 3.

Referring to Figure 4, two half-covers 18, 20 which have been shaped into the form of a hemispherical cup in the manner described above are each adhered, for example by a hot melt adhesive, around a respective hemispherical lining 22, 24 of leather or leatherboard. The linings 22, 24 are preferably stiff and maintain the half-covers 18,20 in the desired hemispherical shape. If desired, the linings 22, 24 may be omitted.

Each half-cover 18, 20 is provided along its peripheral edge with a respective pair of rows of stitches 26, 28 which extends around the respective half-cover 18, 20. The rows of stitches 26, 28 pass through the material of the respective half-cover 18, 20, and lining 22,24 so that in the resultant ball the rows of stitches 26, 28 are visible and are parallel to and spaced from the seam of the ball which is defined by the abutting hemispherical edges 30 of the two half-covers 18, 20. The two rows of stitches 26, 28 are known as "false stitching" since they do not act structurally to hold the two half-covers together but are present to enhance the outer appearance of the ball. The rows of stitches 26, 28 are preferably machine-made or hand-applied. If desired, only one row of "false" stitches is provided on each of the half covers 18,20.Alternatively, the rows of "false" stitches may be omitted.

The half-covers 18,20 are placed in a mould which has a substantially spherical cavity 32 therein. The mould consists of an upper part 34 and a lower part 36. The bottom of the upper part 34 fits as a male part within a female recess in the lower part 36 so that the two parts of the mould are in registry. The half-covers 18, 20 are located in the mould so that the abutting peripheral edges of the two half-covers 18, 20 are horizontal and therefore so that the two pairs of rows of stitches 26,28 are horizontal. Two annular stitch-receiving grooves 38,40 are formed in the inner surface of the mould. Each stitchreceiving groove 38, 40 extends around the cavity and is shaped so that a respective pair of rows of stitches 26, 28 coincide with and are received within the respective stitch-receiving groove 38,40.The stitch-receiving grooves 38,40 accommodate the pairs of rows of stitches 26,28 and so prevent inward deformation by the mould of the half-covers 18,20 in the region of the pairs of rows of stitches 26, 28. When the half-covers are not provided with rows of "false" stitches, the mould is not provided with the two stitch-receiving grooves. An edgereceiving groove 42 is also formed in the inner surface of the mould. The edge-receiving groove 42 extends around the cavity and is positioned on the horizontal circumferential plane of the mould cavity so that it coincides with the abutting edges of the half-covers 18,20. An aperture 44 is formed in the upper part 34 of the mould. A hole 46 in the upper half-cover 18 is in registry with the aperture 44 thereby communicating the inside of the two ha If- covers 18,20 in the mould with the outside of the mould.

To make the ball of the invention, a settable material, such as a synthetic resin material, is poured or injected through aperture 44 and hole 46 so as to fill the space which is surrounded by the half-covers 18, 20 thereby to form a core for the ball.

A preferred synthetic resin material is a self-curing polyurethane which foams and whilst curing has adhesive properties. Typically, on foaming the material has a free rise increase of from 200300%. Injection is stopped when the required weight of the settable material has been injected, the amount being selected so that the resultant ball has the desired weight. Typically, for a cricket ball, about 80% of the space is filled initially with the settable material. The aperture 44 is then closed by a plug (not shown) and then the settable material is allowed to set. Alternatively, the aperture is left open and the settable material is allowed to extend out of the hole 46 in the upper half-cover 18. In the set state the material in the space between the halfcover 18,20 firmly adheres to the inside of the two half-covers so as to adhere them together.The mould is then opened by separating the upper part 34 from the lower part 36 and the ball is removed from the mould. Any excess material extending out of the hole 46 in the upper half-cover 18 is trimmed off.

In an alternative arrangement for making a lighter ball, less than about 50% of the space between halfcovers 18,20 needs to be filled with the settable material. This permits the lighter ball to be made by putting the required amount of settable material into one half-cover, which is in one half of the mould, and then closing the mould and allowing the settable material to foam and set between the two half-covers. This obviates the need to inject settable material through an injection hole in one of the halfcovers. It is merely necessary to provide a means, e.g. a small vent hole or gap in the seam, for the escape of airfrom inside the half-covers during foaming of the settable material.

During the injection and setting of the settable material, the pressure within the space between the two half-covers 18, 20 is increased and this tends to deform outwardly the abutting circumferential edge of the two half-covers into the edge-receiving groove 42. This forms a raised circumferential seam 48 around the ball. After the ball has been removed from the mould, the seam 48 between the two halfcovers 18,20 is stitched, either by hand or by machine, to form a stitched seam having two rows of stitches 50 (see Figure 3) which secure together the two half-covers 18,20 along their circumferential peripheral edges.The seam 48 is stitched in a known manner and the stitches are positioned between the opposing pairs of rows of stitches 26, 28. Since a raised circumferential seam 48 is formed prior to the seam stitching step by virtue of the provision of the edge-receiving groove 42, this greatly facilitates stitching of the seam since a needle or awl can readily be passed through the raised seam during the stitching step.

When the rows of "false" stitching are omitted, the ball may be hand-stitched so that each halfcover 18,20 has three rows of stitching, the inner row of stitching forming the stitched seam 48. This produces a ball having an entirely hand-stitched seam.

In the manufacture of a cricket ball for outdoor use, the set material of the core typically has an average density of about 0.8 g/cm3. This results in a cricket ball having the regulation size and weight as prescribed by the cricketing authorities.

If desired, the core may incorporate the fibre reinforcing means which are disclosed in our British Patent Specification No. 2147815.

The ball described with reference to Figure 4 requires fewer stitches across the slit than in a conventional ball since the set material of the core adheres the two sides of the slit together and this reduces the tendency for the closed slit to open. The preferred number of stitches in this embodiment is from 6 to 14 when the diameter of the ball is about 7 cm and the length of each slit is from 6.5 to 9.5 cm.

In a further alternative embodiment of the invention, the two half-covers 18, 20 which have been made in the manner described above are employed to form a ball in accordance with the method disclosed in our British Patent Specification No. 2097320. That method differs from that described with reference to Figure 4 by not requiring the two half-covers 18,20 to be stitched together.

Instead, all of the adhesion between the two halfcovers 18,20 is provided by the set material which forms the solid core of the ball. If desired, a further row of false stitching is provided around the peripheral edge of each half-cover 18, 20 so that the resultant ball has the same general appearance as that shown in Figure 3. Alternatively, the stitching may be omitted so that the resultant ball has no visible stitches on its outer surface.

The present invention may be applied to balls other than cricket balls, such as hockey balls.

Claims

1. A method for making a ball, the method comprising the steps of: (a) providing two substantially hemispherical cover-forming pieces for the ball, each coverforming piece comprising a single piece of material having an elongate slit through the thickness thereof, the slit having been closed by stitches which are disposed on one side only of the material; and (b) securing the two cover-forming pieces around a solid core for the ball so that each closed slit extends around a major part of the respective hemispherical cover-forming piece but stops short of the seam between the two cover-forming pieces and so that the stitches which close each slit are concealed within the ball.

2. A method according to Claim 1, wherein the two cover-forming pieces are secured around the core by stitching together the peripheral edges of the two cover-forming pieces.

3. A method according to Claim 2, wherein each slit is from 6.5 to 9.5 cm long, the diameter of the ball is about7 cm and each slit is closed by from 14 to 20 stitches.

4. A method according to Claim 1, wherein in step (b) the two cover-forming pieces are secured around the solid core by the steps of: (i) providing a mould having a substantially spherical cavity therein; (ii) putting a settable material into the space which is surrounded by the cover-forming pieces; (iv) allowing the settable material to set so that the set material adheres the two cover forming pieces together; (v) removing the ball from the mould; and (vi) stitching together the abutting edges of the two cover-forming pieces so that the ball has a stitched circumferential seam.

5. A method according to Claim 4, wherein stitching step (vi) is carried out by hand.

6. A method according to Claim 4, wherein the stitching step (vi) is carried out by machine.

7. A method according to any one of Claims 4 to 6, wherein the mould is provided with an edge receiving groove which extends around the cavity and is shaped so that when the cover-forming pieces are placed in the mould the edge of each cover-forming piece coincides with the groove whereby on putting the settable material into the said space the edges of the cover forming pieces can deform outwardly into the groove.

8. A method according to Claim 1, wherein in step (b) the two cover-forming pieces are secured around the solid core by the steps oft (i) providing a mould having a substantially spherical cavity therein; (ii) placing the two cover-forming pieces within the mould so as to line the cavity; (iii) putting a settable material into the space which is surrounded by the cover-forming pieces; (iv) allowing the settable material to set so that the set material adheres the two cover forming pieces together; and (v) removing the ball from the mould.

9. A method according to any one of Claims 4, 5,6, or 8, wherein the slit is from 6.5 to 9.5 cm long, the diameter of the ball is about 7 cm and each slit is closed by from 6 to 14 stitches.

10. A method according to Claim 8 or Claim 9, wherein the mould is provided with an edgereceiving groove which extends around the cavity and is shaped so that when the cover-forming pieces are placed in the mould the edge of each cover-forming piece coincides with the groove whereby on putting the settable material into the said space the edges of the cover-forming pieces can deform outwardly into ihe groove.

11. A method according to any foregoing claim, wherein prior to securing step (b) at least one row of stitches is sewn around the peripheral edge of each cover-forming piece.

12. A method for making a ball substantially as hereinbefore described with reference to Figures 1 to 3 or Figure 4 of the accompanying drawings.

13. A ball whenever made by the method of any foregoing claim.

14. A ball comprising a cover which is formed from two substantially hemispherical cover-forming pieces, each cover-forming piece comprising a single piece of material having an elongate slit through the thickness thereof, the slit having been closed by stitches which are disposed on one side only of the material, and a solid core around which the two cover-forming pieces are secured so that each slit extends around a major part of the respective hemispherical cover-forming piece but stops short of the seam between the two coverforming pieces and so that the stitches which close each slit are concealed within the ball.

15. A ball according to Claim 14, wherein the two cover-forming pieces are secured around the solid core by stitching together the peripheral edges of the two cover-forming pieces.

16. A ball according to Claim 15, wherein each slit is from 6.5 to 9.5 cm long, the diameter of the ball is about 7 cm and each slit is closed by from 14 to 20 stitches.

17. A ball according to Claim 14, wherein the solid core comprises a set material which has been formed by putting a settable material into the space which is surrounded by the two cover-forming pieces and allowing the material to set so that the set material holds the two cover-forming pieces together and further comprising a row of stitching which stitches together the abutting edges of the two cover-forming pieces so that the ball has a stitched circumferential seam.

18. A ball according to Claim 17, wherein the stitched circumferential seam is hand stitched.

19. A ball according to Claim 17, wherein the stitched circumferential seam is machine stitched.

20. A ball according to Claim 14, wherein the solid core comprises a set material which has been formed by putting a settable material into the space which is surrounded by the two cover-forming pieces and allowing the material to set so that the set material holds the two cover-forming pieces together.

21. A ball according to any one of Claims 17 to 20, wherein each slit is from 6.5 to 9.5 cm long, the diameter of the ball is about 7 cm and each slit is closed by from 6 to 14 stitches.

22. A ball according to any one of Claims 14 to 21 further comprising at least one row of stitches which is sewn around the peripheral edge of each coverforming piece.

23. A ball substantially as hereinbefore described with reference to Figures 1 to 3 or Figure 4 of the accompanying drawings.