GB1573079A - Games ball - Google Patents

Description

(54) GAMES BALL (71) We GALA, narodni podnik of Prostejov-Krasice, Czechoslovakia, a body corporate organised and existing under the laws of Czechoslovakia, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to a gamesball, especially for handball, volleyball or football, comprising a base member particularly a rubber bladder, provided with an inflating valve, the surface of which base member is wrapped into reinforcing windings of ropes, threads, yarn or filaments, and surface cover segments, generally of natural or synthetic rubber or leather which are regularly distributed around the said windings and separated one from another with a network of rubber ribs.

The construction of moulded games balls has throughout the years of technical development accompanied with the manufacture thereof gradually developed to the arrangement, comprising an inner rubber bladder provided with an inflating valve, which bladder is wrapped with a winding of ropes, threads, yarn or filaments, properly bonded to the bladder.

Between a network of rubber ribs of varying forms, there is applied a system of surface cover parts or segments upon the winding. The cover parts acquire the form of precisely geometrically distributed segments, made mostly of natural or synthetic leather, and in some instances also of rubber, all of which depends of course to a considerable extent on the pertinent type of ballgame for which the balls are intended.

It is common practice in the art of games ball manufacture to depress the above mentioned winding of ropes, yarn, threads or filaments into a layer of rubber, which in the later manufacturing steps will be vulcanised, which results in a tight bond between the inner rubber bladder and the winding of ropes, threads, yarn or filaments; however, the bond cannot be split apart. Although this arrangement is of a great advantage from the viewpoint of manufacturing the games balls, it does not enable an exchange of the inner rubber bladder in the case of eventual damage thereof, which may, in fact, result in the games ball being unfit for further use.

On the contrary, it is possible to exchange with relative simplicity the damaged surface cover segments, the system of which is to the games ball winding adhesively bonded between the network of rubber ribs. The bond made by use of adhesive may be quite easily split apart.

However, the necessity of repairing this ball type is not very frequent and further the solution of this problem may be found under different conditions of an embodiment of the games balls. However, the principle problem of games balls of this type lies in the unsplittable bond or joint between the inflatable rubber bladder and the winding of the ropes, threads, yarn or filaments.

According to the present invention there is provided a grames ball comprising a base member in the form of an inflatable rubber bladder, the surface of which member is wrapped with reinforcing windings of ropes, threads, yarn, filaments or the like, and surface cover segments which are regularly distributed around the said windings and separated one from another with a network of rubber ribs, the base member being bonded to the windings of the ropes, yarn, threads or filaments with a bond made of a rubber or like solution or dispersion type adhesive, which bond is separable while the bond between the ropes, threads, yarn or filaments and the surface cover segments is made of an intermediate vulcanised layer which cannot be separated.

The games ball according to the present invention, enables the possibility of removing the inner rubber bladder from the games ball without destroying or disturbing the inner wall of the wrapping winding from the ropes, yam, threads of filaments, owing to the fact that the bond made in using the solution or the dispersion type of the tubber adhesive may be split apart. On the other hand, the danger of delaminating the surface cover segments from the winding is substantially suppressed as a result of the unsplittable vulcanised bond, executed by the rubber intermediate layer. As this intermediate rubber layer flows in sufficient quantities into the gaps between the individual cover segments during the subsequent vulcanisation step, it prevents the possibility of initial splitting off of the surface cover segment peripheries.

The games ball in preferred embodiment of the present invention is manufactured as follows. Using a hollow steel needle a rubber bladder is inflated by means of pressurised air.

The rubber bladder is fixed in a template and it is inflated to the desired maximum perimeter.

Thereafter, the inflated rubber bladder is fed into a machine in which the deposition of the ropes, yam, threads or filaments of the windings upon the bladder surface is performed.

The winding is oriented into all directions, so as to achieve a regularly deposited thick network of windings upon the surface of the bladder, while, of course, the continuous curve of the individually deposited ropes, yarn, threads or filaments follows always the path of the great circle of the circumference of the inflated bladder surface. The individual ropes, yarn, threads or filaments may be preferably of synthetic materials, such as for instance of polyamide fiber PA-100/24/N, or of natural fibers, which may be taken into account, such as cotton yarn 68/2x2. Preferably a combination of synthetic and natural ropes, yarn, filaments, etc. is used; for example it is of a great advantage to use for the preparation of the complete winding three strands of a synthetic material and one strand of a cotton yarn.The topes, yarn, etc. of the synthetic material pass prior to being deposited upon the surface of the inflated rubber bladder, through a solution or a dispersion of materials with adhesive properties, whereby their unchanging position upon the bladder surface is secured or anchored immediately.

When a greater number of synthetic ropes, yarn, etc. is wound around the surface of the inflated rubber bladder simultaneously, the coating of the solution or dispersion of materials with adhesive properties must not be coated upon all of the strands; it has proved as sufficient, if the dispersion or the solution is coated at least on prevailing majority thereof. With natural materials, the suction capacity of which is much greater than that of the synthetic materials, the coating of materials with adhesive properties is not performed. For the local stabilisation of the winding strands, which do not contain the coating of the adhesive materials, a certain "excess" thereof is sufficient, which adhered to the winding strands, which have been deposited from the fibers of synthetic materials with reduced suction capacity.

For the coating of the material with adhesive properties upon the ropes, yarn, etc. from which the windings are deposited around the inflated rubber bladder, solutions of rubber may be used in organic solvents; it is, though, much more advantageous to use aqueous dispersions of rubber-like materials, which do not only possess the adhesive properties, but at the same time, they do not contaminate the environment with vapours of organic solvents used, the latter being mostly of a toxical character. For example, it is very suitable to use a 60 per cent aqueous dispersion of a pre-cured natural rubber; the dispersion has to be diluted to approximately a 40 per cent solids content before the use and prior to passing the winding strands therethrough.

The ropes, yarn, threads or filaments are fed from a coil, mounted on a winding machine, via a system of guide members, either through a container filled with a solution or a dispersion of materials with adhesive properties, or outside this container, all the way to the inflated rubber bladder; to the surface of the inflated rubber bladder, the ropes, yarn, threads or filaments are pressed by means of a special roller, which controls the rotation of the bladder at the same time.The purpose of winding the ropes, yarn, etc. upon the surface of the inflated rubber bladder with the use of the method according to the present invention, in which a predominant majority of the strands being wound is coated with a coating of material exhibiting adhesive properties, is to immediately lock the position of the winding strands on the appropriate position of the bladder surface without the risk of an eventual shifting of the position thereof during the later manufacturing steps.

At the same time, the absorption of the excess material with adhesive properties takes place, as a result of strands of the natural fibers used, in which way use is made of the absorption properties thereof. The combined winding of the synthetic and natural fibers removes an undesired agglomeration of the adhesive dispersion particles at the crossing points of the fibers, as well as the formation of undesired solids particles, which in the case of their eventual occurrence, form projections upon the surface of the games ball reinforced inner bladder in the final phase of the winding step.

The overall quantity of the ropes, yam, etc.

necessary for completion of the reinforcing winding of a single games ball, equals to from 10,000 to 30,000 meters; to this corresponds also the consumption of the adhesive materials, related to solids content, equaling to approxi mately from 4 to 10 grams. The suitable material of this type is the 40 per cent dispersion of natural rubber, sold commercially under the Trade Mark Revertex LR.

The rubber bladder with the winding of ropes, yarn, etc. which has been prepared by the method according to the present invention, is thereafter dried for about 30 minutes, in order to evaporate the substantial portion of the water content. Thereupon, ironing of the bladder is done in a smooth mould, the diameter of which is slightly enlarged, when compared with the diameter of the inflated rubber bladder, the enlargement corresponding substantially to the value, which equals to the thickness of the windings deposited upon the bladder surface.

Such, for instance, when the diameter of the inflated rubber bladder equals to 198 mm. the smooth ironing mould has the diameter of 201 mm. while for the inflated rubber bladder of 200 mm. diameter, an ironing mould will be used of 204 mm. diameter. Temperatures ranging from 110 to 1000C are used for the ironing step. The ironing step has the effect of local stabilisation of the ropes, yarn, etc. in the previously acquired pattern, or rather terminating of the local stabilisation upon the surface of the inflated rubber bladder with simultaneous vulcanisation, eventually coagulation of the adhesive dispersion used; in the ironing step, the remaining portion of the humidity from the ironed game ball carcass is evaporated completely. The carcass is thereafter let to cool, and it is then passed towards the further manufacturing steps.

The appropriately inflated bag of the games ball provided with the reinforcing layer of the thread or rope windings, and thereafter calibrated by the previous ironing operation, is clamped around a mid-periphery separating the bag hemispheres, whereupon one, or both of the rubber sheet segments, is or are simultaneously applied upon the games ball bag, which had been previously coated with a thin layer of an adhesive of the same composition as is the adhesive used for the application of the sheet segments.

Owing to the elasticity of the rubber sheet segments the segments are appropriately shaped to substantially acquire the shape of the games ball hemisphere as a result of depressing down the clamping circular rings to cover the games ball enlarged cap upon the surface of the bag, with the rubber sheet reaching only to the desired distance from the game ball parting plane with no folds occurring during the application thereof. As the rubber sheet segments are provided with the adhesive coating on the reverse side, the sheet is anchored upon the games ball segments from both sides in precise positions, which are determinated by the clamping circular rings.Then both of the sheet segments caps are cut around the peripheries thereof, whereby an uncoated strip is left in the central part of the games ball bag around the maximum circle of this circumference; to this part is thereafter applied another segment of the rubber sheet, which has been previously formed into a strip of the suitable width. The periphery of the rubber sheet strip must be applied accurately between the peripheries of both of the previously applied cup segments, as the peripheries of the rubber segments must not be overlapping in any place.

For the reliable manufacture of the rubber rib network between the individual cover segments upon the moulded games ball surface, it is important that the sheet is formed from the rubber mixture, which is being used as an intermediate layer for joining the winding of the inflated rubber bladder the so called bag, and the surface cover segments. Substantially, this sheet is made of a mixture of natural rubber and of synthetic rubber, eventually of their mutual mixtures, with an admixture of accelerators, fillers, antioxidizing agents, lubricating agents, dyestuffs, and of the remaining necessary components.

For satisfactory application of the method, this mixture must have a built-in vulcanising system contained therein, which corresponds to the requirements of the final ironing of the game ball, namely the temperature range of from 100 to 130 C for a period of from three to maximum five minutes at the pressure of five atmospheres. Under the given conditions, the rubber mixture is vulcanised to such an extent, that the rubber ribs are resistent against deformations, which might eventually result from the handling of the games balls when used.

The sheet of the rubber mixture for the manufacture of the rubber ribs must especially be capable of uniformly covering the globe surface, that is to say, the inflated rubber bladder wrapped with the reinforcing winding without the occurrence of undesired folds around the peripheries of the adjoining edges; It must therefore exhibit sufficient degree of elasticity. In flowing into the grooves of the marking mould it must provide for reliable marking of the positions of the surface cover segments to be subsequently applied; it must therefore exhibit sufficient viscosity. It must secure vulcanisation, eventually gelatination at temperatures, which do not exceed the limits of the temperature resistence of the surface cover segments used; it must therefore contain a suitable vulcanisation system build-in therein.

It must be capable of flowing sufficiently into the gaps between the bonded surface cover segments during the steps of the vulcanising and ironing; the viscosity of the rubber mixture must therefore be sufficiently high, even to suit this important operation. Finally, when varying the properties of the rubber mixture sheet and the quantities thereof applied, one may not only influence the weight of the games balls, but also the final utility properties, especially the elasticity of the games balls.

The sheet of the rubber mixture for the manufacture of the rubber ribs, or rather the network of the rubber ribs, between the individual cover segments upon the surface of the moulded games balls contains a vulcanising system which comprises from 2,7 to 3, 6 per cent by weight of a mixture of vulcanisation accelerators, namely the mixture of mercaptobenzthiazole, tetramethylthiuram disulphide, and N,N-diphenyl guanidine, along with from 0, 2 to 0,4 per cent by weight of isobutylidenebis4, 6-dimethyl phenole. The thickness of the rubber sheet ranges for the purposes of the method according to the present invention from 0,4 to 1,5 mm.

A typical example of a mixture for the preparation of the rubber ribs is a mixture, which, related to 1000 parts by weight, contains 185 parts by weight of natural rubber, 7 parts by weight of butadi-ene-styrene copolymer rubber, 7 parts of weight of sulphur, 8 parts by weight of zinc oxide, 5,5 parts by weight of marcaptobenzthiazole, 7,2 parts by weight of tetramethylthiuram disulphide, 15 parts by wieght of N,N-diphenyl guanidine, 2 parts by weight of isobutylidene-bis4, 6-dimethyl phenole, 4 parts by weight of stearine, 50 parts by weight of carbon-black, and 429 parts by weight of calcium carbonate.

The rubber mixture may be prepared in many modifications, and in various colour shades. Use may be made also of thermoplastic rubbers, and even of suitable plastics materials.

When preparing the rubber mixture, one does not proceed in the conventional manner; rather specific manufacturing steps and temperatures have to be observed when preparing the rubber mixture. The same is also true for the sheet made from this mixture. The rubber batch is prepared conventionally in a two-roller calender, whereupon the accelerators and sulphur are admixed to the mixture in precisely selected quantities, while keeping the operation temperatures at minimum values. After the rubber mixture, containing the vulcanisation agents has been prepared in the two-roller calender, it is transferred immediately into a four-roller or a five-roller calender in several successive doses, where it is calendered into the sheet of desired thickness.

The temperature of the mixture upon the calender must not exceed 60"C. The thus prepared sheet is thereafter cut into desired segments. The application of the sheet upon the games ball bag in making the rubber ribs is as follows:-- the prepared segments, that is to say, the circles of desired diameter, are clamped by means of a specially designed equipment, whereupon a coating of a diluted adhesive is applied thereon. The sheet may also be activated by. means of a suitable organic solvent, such as for instance gasoline.

In this way, a uniform application of the rubber sheet around the whole plane of the games ball sphere is achieved. Thereafter, the profile of the games ball is marked to indicate the precise positions of the surface cover segments to be applied upon the prepared bag of the game ball, provided with a coating of the rubber sheet. This is done in pressing the game ball bag in a mould, provided with grooves of desired depth and form, which secure the characteristic design of the final game ball surface. The said pressing is done under conditions of mild temperatures. Owing to the viscosity of the rubber sheet mixture, the softened mixture flows into the mould grooved parts, which results in precise marking of the areas for the future application of the surface cover segments.The thus prepared games ball bag is then further processed by adhesive bonding the surface cover segments and by ironing and eventually by vulcanising the rubber sheet to form the rubber ribs.

First, the surface cover segments of the desired shape are cut from natural leather, or possibly from synthetic materials, using a cutting machine; the peripheries of these segments are skived on the reverse sides on a skiving machine to the width of about 6 mm. the skiving width itself depending on the character of the cover material and on the games ball type. Thereafter, a coating of an adhesive is applied on the reverse side of the segments, and also on the surface of the games ball bag. The adhesive used is a solution of natural rubber, vulcanisation agents and dyestuffs with fillers, dissolved in an organic solvent, such as in gasoline.

When applying the coating of the adhesive to the reverse side of the cover segments, a solution of higher solids content is used, ranging from 18 to 20 per cent. For the application of the adhesive to the games ball bag, a thinner solution with the solids content in the range of from 10 to 15 per cent may be used.

The coating of the adhesive onto the reverse side of the cover segments is applied manually, but a suitable coating machine may be used as well, and the adhesive, as has been already mentioned, is applied to the reverse side of the segments. To the games ball bag, the adhesive may also be applied manually; also in this case, a suitable adhesive coating machine may be used.

After the adhesive has been coated to both of the surfaces to be adhesive bonded, the cover segments are applied upon the games ball bag, after an interval of from 5 to 45 minutes, in such a manner, as to precisely fit into the predetermined areas, which have been marked by the grooves of the marking mould as has been described hereinbefore.

The shape of the games ball fields, as well as the shape of the cover segments, are specific for each of the games ball types. When applying the surface cover segments, no substantial physical effort is required for pressing of the segment peripheries to achieve the tight bonds.

A perfect adhesion between the game ball bag, the rubber sheet and the cover material, results as a matter of course from the sufficient flowing of the rubber sheet mixture and from its vulcanising by the application of elevated temperatures during the ironing step. During this operation, the precise position of the surface cover segments is sufficiently stabilised owing to the confection adhesive stability of the adhesive used. After the cover segments have been applied, excess of the adhesive, and also other impurities are removed from the game ball surface, which thus is prepared for ironing. The following ironing and the vulcan- isation of the games balls are performed in spherical moulds consisting of two closable hemispheres. The size of the mould is determined by the games ball type.The temperatures used and the ironing time of the game ball, and also the vulcanisation of the rubber mixture sheet, depend upon the type of the cover material, and upon the temperature resistance thereof, the temperatures ranging from 90 to 1300C. In the case, where synthetic materials are used with a high degree of resistance to elevated temperatures, even substantially higher temperatures may be used eventually. The ironing and the vulcanisation times are depending upon the temperatures used.

Usually, the time ranges between 2 and 7 minutes; for the case of higher temperatures, the time may even be shorter. The purpose of the ironing step for the games ball is to achieve a smooth and a uniform surface of the games ball, while maintaining or securing its round shape.

In vulcanising the mixture, the formation of the rubber rib network is achieved due to the perfect flow of the softened mixture into the gaps between the peripheries of the cover segments. In the first phase, the mixture becomes plasticised under the effect of heat, and in the second phase, a perfect bond between the cover segments and the sheet, and, in turn, between the sheet and the games ball bag is achieved, as a result of vulcanising the mixture and the adhesive in the given state. Substantially, higher degree of peeling strength between the cover segments and the game ball bag is achieved, as well as a higher reliability of the bond itself. The peeling of the cover segment peripheries takes is almost completely avoided as was the case with balls made by previous methods of manufacture.

To preserve the characteristic shape of the game ball surface, namely, the graduation of the surface, resulting from the plastical composition of the cover segments with lowered peripheries thereof, it is of importance to skive the surface cover segments. The skiving of the peripheries of the cover segments and the relatively high degree of overpressure inside the games ball during the ironing and the vulcanising steps, secure perfect sealing of the skived or bevelled peripheries into the sheet material, which results in a very tight bond. After the steps of the sheet vulcanising and the game ball ironing, the pressure inside the game ball bladder is substantially reduced ;the overpressure used during the operation of vulcanising and of ironing the game ball, will during the practical use of the game ball never be repeated.

At the substantially lower inflating pressure in the games ball it will be practically impossible for the surface thereof to become smooth again, so that, owing to the skived peripheries of the cover segments, the game ball surface will preserve its typically articulate appearance.

Should some of the games ball type require the surface to be perfectly round, with exclusion of the pronounced characteristics of the articulation resulting from the varying thickness of the cover segments, the aforementioned skiving of the peripheries of the cover segments is omitted.

The games ball surface then keeps its perfectly round shape and appearance, without any plastical pronouncements of the individual segments. This pronouncement may then acquire only the optical appearance, while preserving the equally tight bond between the surface cover segments with the games ball bag.

The above mentioned ironing having been terminated, the games ball are let to cool and thereafter, they are inflated to the required pressure for the air-tightness checking. The finished games balls are despatched in the inflated, or in an emptied state.

EXAMPLE: A rubber bladder is prepared, which is inflated to the diameter of 196 mm. in such a manner, as to guarantee the required roundness within the plus and minus tolerance of 2 mm.

The surface of the bladder is reinforced with a yarn winding on a proprietary winding machine.

To accomplish the winding, a strand of the yarn is manually anchored to the bladder surface with subsequent winding thereof around the bladder, whereupon the winding step procedes automatically, using the mentioned winding machine. The path of the yarn wound on the rubber bladder always follows the maximum circumference of the bladder with four strands being wound simultaneously. Out of the four strands, three are of polyamide yarn of the commercial mark PAD-100/24/N; two strands of the polyamide yarn pass through a latex bath, whereby sufficient adhesion of the yam to the bladder surface, eventually to the previously wound layers of the winding is secured.The remaining strand of the polyamide yarn, and one strand of natural silk, are wound simultaneously with the previously mentioned two strands of the polyamide yarn, without of course passing the former through the latex bath. This is to prevent an excess absorption of the latex adhesive onto the yarn in connection with the polyamide yarn; as fare as the cotton yarn is concerned, this secures a uniform distribution of the moisture and of the latex solids across the winding surface. The distribution of the moisture and of the adhesive is secured by the absorption property of the natural fibres, eventually of the fibres of regenerated cellulose.

In the present embodiment of the games ball, the time necessary for completion of the winding, equals to 12.5 minutes. This time is not only sufficient for the completion of the winding in the required quantity of the yarn, but at the same time, for covering the whole surface of the bladder, as a result of which, the desired strength and shape stability of the finished game ball are achieved. In this example, the adhesive used is a 20 to 25 per cent precured latex of the type Revultex LR.

After the winding of the inflated bladder is terminated, the water content from the adhesive evaporates freely for about 30 minutes, whereupon the winding is ironed in a smooth mould, heated to temperatures ranging from 100 to 11 00C for about one minute, using the pressure of five atmospheres.

On to the ironed games ball bag, made by winding a mixture of synthetic and of natural yarn on an inflated rubber bladder, a layer of an adhesive is coated in the form of a 20 per cent solution of natural rubber in gasoline. The same coating of the adhesive is simultaneously applied to one of the surfaces of the rubber sheet with thickness ranging from 0.5 to 0.6 mm. which is then clamped in a special tool, designed for applying the sheet upon the round, inflated game ball bag. The sheet is applied after from 20 to 30 minutes have elapsed since coating the adhesive.

The successive individual steps of the rubber mixture sheet application consists in centering two sheet hemispheres, which are then formed during the applying, and in applying a central strip of the sheet, which compensates the eventual irregularities that might have occurred during the application of the hemispheres. The application of the sheet central strip to the aforementioned hemispheres is made carefully, to prevent overlapping of the individual segments, as the surface of the finished game ball would show irregular projections in those points.

After the sheet has been applied onto the games ball bag, the pressing of the same takes place in a profiled cold mould, to uphold the bonding between the sheet and the game ball bag by pressing step, and eventually to mark orientation points and grooves upon the bag surface, in order to make the later application of the cover segments easier.

The ironed game ball bag is provided with a coating of an adhesive of the type of a 20 per cent solution of natural rubber in gasoline.

Simultaneously, the reverse side of the cover segment is coated with the same type of the adhesive, with two coats following one after another. After minimum 30 minutes have elapsed since applying the coating of the adhesive, the same has dried, and the cover segments made of natural leather are bonded onto the prepared game ball bag.

Thereafter, the cover segments having been applied, the game ball is conditioned at least for one hour with subsequent ironing and vulcanisation of the same. The purpose of the ironing and of the vulcanisation is to correct or to smoothen eventual irregularities around the game ball surface, which might have occurred during the bonding step of the cover segments, and during the vulcanisation of the rubber mixture. The ironing and the vulcanisation takes place in a smooth, round mould of 20 cm. diameter at temperatures in the range of from 100 to 1 100C for three minutes. After the games ball has been ironed, it is let to cool and after inflating to the required pressure in the inner rubber bladder, the games balls then pass after 24 hours for technical checking and to despatch.

Reference is made to the present applicant's co-pending application No. 11317/78 (Serial No. 1 573 078) which describes and claims a bladder wrapping method as employed above.

WHAT WE CLAIM IS: 1. A games ball comprising a base member in the form of an inflatable rubber bladder, the surface of which member is wrapped with reinforcing windings of ropes, threads, yarn, filaments or the like, and surface cover segments which are regularly distributed around the said windings and separated one from another with a network of rubber ribs, the base member being bonded to the windings of the ropes, yarn, threads or filaments with a bond made of a rubber or like solution or dispersion type adhesive, which bond is separable, while the bond between the ropes, threads, yarn or filaments and the surface cover segments is made of an intermediate vulcanised layer which cannot be separated.

2. A games ball according to Claim 1, wherein the bond between the windings of the ropes, yarn, threads or filaments and the surface cover segments, is integral with the network of rubber ribs.

3. A games ball as claimed in Claim 1 and substantially as hereinbefore described.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (3)

**WARNING** start of CLMS field may overlap end of DESC **. eventually of the fibres of regenerated cellulose. In the present embodiment of the games ball, the time necessary for completion of the winding, equals to 12.5 minutes. This time is not only sufficient for the completion of the winding in the required quantity of the yarn, but at the same time, for covering the whole surface of the bladder, as a result of which, the desired strength and shape stability of the finished game ball are achieved. In this example, the adhesive used is a 20 to 25 per cent precured latex of the type Revultex LR. After the winding of the inflated bladder is terminated, the water content from the adhesive evaporates freely for about 30 minutes, whereupon the winding is ironed in a smooth mould, heated to temperatures ranging from 100 to 11 00C for about one minute, using the pressure of five atmospheres. On to the ironed games ball bag, made by winding a mixture of synthetic and of natural yarn on an inflated rubber bladder, a layer of an adhesive is coated in the form of a 20 per cent solution of natural rubber in gasoline. The same coating of the adhesive is simultaneously applied to one of the surfaces of the rubber sheet with thickness ranging from 0.5 to 0.6 mm. which is then clamped in a special tool, designed for applying the sheet upon the round, inflated game ball bag. The sheet is applied after from 20 to 30 minutes have elapsed since coating the adhesive. The successive individual steps of the rubber mixture sheet application consists in centering two sheet hemispheres, which are then formed during the applying, and in applying a central strip of the sheet, which compensates the eventual irregularities that might have occurred during the application of the hemispheres. The application of the sheet central strip to the aforementioned hemispheres is made carefully, to prevent overlapping of the individual segments, as the surface of the finished game ball would show irregular projections in those points. After the sheet has been applied onto the games ball bag, the pressing of the same takes place in a profiled cold mould, to uphold the bonding between the sheet and the game ball bag by pressing step, and eventually to mark orientation points and grooves upon the bag surface, in order to make the later application of the cover segments easier. The ironed game ball bag is provided with a coating of an adhesive of the type of a 20 per cent solution of natural rubber in gasoline. Simultaneously, the reverse side of the cover segment is coated with the same type of the adhesive, with two coats following one after another. After minimum 30 minutes have elapsed since applying the coating of the adhesive, the same has dried, and the cover segments made of natural leather are bonded onto the prepared game ball bag. Thereafter, the cover segments having been applied, the game ball is conditioned at least for one hour with subsequent ironing and vulcanisation of the same. The purpose of the ironing and of the vulcanisation is to correct or to smoothen eventual irregularities around the game ball surface, which might have occurred during the bonding step of the cover segments, and during the vulcanisation of the rubber mixture. The ironing and the vulcanisation takes place in a smooth, round mould of 20 cm. diameter at temperatures in the range of from 100 to 1 100C for three minutes. After the games ball has been ironed, it is let to cool and after inflating to the required pressure in the inner rubber bladder, the games balls then pass after 24 hours for technical checking and to despatch. Reference is made to the present applicant's co-pending application No. 11317/78 (Serial No. 1 573 078) which describes and claims a bladder wrapping method as employed above. WHAT WE CLAIM IS:

1. A games ball comprising a base member in the form of an inflatable rubber bladder, the surface of which member is wrapped with reinforcing windings of ropes, threads, yarn, filaments or the like, and surface cover segments which are regularly distributed around the said windings and separated one from another with a network of rubber ribs, the base member being bonded to the windings of the ropes, yarn, threads or filaments with a bond made of a rubber or like solution or dispersion type adhesive, which bond is separable, while the bond between the ropes, threads, yarn or filaments and the surface cover segments is made of an intermediate vulcanised layer which cannot be separated.

2. A games ball according to Claim 1, wherein the bond between the windings of the ropes, yarn, threads or filaments and the surface cover segments, is integral with the network of rubber ribs.

3. A games ball as claimed in Claim 1 and substantially as hereinbefore described.