DE2211816A1 - Method and apparatus for applying a coating to a core - Google Patents

Description

Dr. F. Zumsteln sen. - Dr. E. Assmann Dr. R. Koenigsberger - Dlpl.-Phys. R. Holzbauer - Dr. F. Zumsteln Jun.

PATENT LAWYERS

TELEPHONE: COLLECTIVE NO. 225341

TELEX 529979

TELEGRAMS: ZUMPAT CHECK ACCOUNT: MUNICH 91139

. BANK ACCOUNT: BANK H.AUFHÄUSER

8 MUNICH 2,

BRÄUHAUSSTRASSE 4 / HI

4 / Ii
ECS / ISC 4974

DUNLOP HOLDINGS 1IMITED, London S.W.1

Method and device for applying a

Coating on a core.

The invention "relates to a method and an apparatus for Applying a coating to a core.

The invention provides a method of applying a coating to a core in which the external dimensions of the core are reduced by the application of external pressure the coating is applied to the reduced core, and then the pressure is released so that the core essentially returns to its original size.

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This makes it possible in an advantageous manner to apply a tightly fitting coating over the core - (the coating can in the End product be slightly stretched) - without raising the difficulties usually associated with achieving a dense, but uniform concern are associated when a coating is applied to a core of normal size.

The invention is particularly useful in applying coatings to hollow spherical cores such as tennis ball cores, and for the sake of simplicity is described below only with reference to tennis balls, although it is clear that the invention has a further field of application and should not be limited to tennis balls.

Accordingly, the invention further provides a method of application a coating on a hollow, spherical core, e.g., a tennis ball core, the hollow core of which is in size is reduced by the application of an external pressure, the coating is applied to the reduced core and. the pressure is slackened so that the core returns substantially to its original size.

Compressed air is a convenient means of applying the Pressure, although other gases or other means can be used if desired.

The coating can consist of more than one piece. For example, tennis ball covers or "mushrooms" as they are commonly known are used are conventionally applied as two separate, substantially identical, dumbbell-shaped pieces. Everyone felt has a coating of a suitable adhesive applied to a surface and the adhesive coated surface is then applied to the core. Alternatively, the adhesive can be applied to the surface of the core or to the felt and the core can be applied. Ideally, each felt will be 30

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applied to the core that the major axis of the mushroom is on a great circle of the spherical core. The two great circles which correspond to the two mushrooms should ideally lie in planes that run at right angles to each other. Each mushroom then lies on the core in such a way that its major axis forms a continuous circle with the minor axis of the other Forms fungus. The minor axis is the axis that runs perpendicular to the major axis and is in the middle the length of the mushroom. In practice, the mushrooms are usually stretched into place on the core by hand, or the first mushroom is applied mechanically and the second by hand. This means that the final location of the mushrooms will hardly be the ideal location and the finished product has no uniformity. E.g. a fungus can be considerable be more stretched than the other. Various mechanized methods of application have been suggested, but these have worked it was usually necessary to stretch the mushrooms into place, and they were not used with any greater success. The present invention, on the other hand, provides a means of applying the mushrooms with a great deal of adjustability and Uniformity is possible because the mushrooms can be brought into their position in an unstretched state.

The invention further provides an apparatus for applying a coating to a core which has a holding device for the core, means for applying external pressure to the core, applying means for the coating on the core, and means for relieving pressure on the core.

The means for applying the pressure to the core and releasing the pressure from the core may suitably by conventional air lines and valves to be connected to a source of compressed air are formed.

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The support means for the core can be, for example, pins are formed. In a "preferred embodiment, however, and if the coating is applied in more than one piece, the core can enter the coating or fungus zone on a first one Holding device are brought and can then be clamped in a frame that covers the surface areas of the core separates and delimits which correspond to the various pieces or parts of the coating. The first holding device can then subtracted from.

If that way a! Dennisballkern with the help of this preferred Embodiment of the invention is covered, the core prior to the application of the coating, a frame is arranged on it, which is shaped so that it follows the seam lines of the coating on the finished ball. By doing this, the glue-coated edges of each mushroom that. to be applied, held so that it does not interfere with the edges of any other mushroom to be applied. come into contact while the central parts of the mushroom are pressed into adhesive contact with the core. It is at This device is advantageous in that the application of the adhesive-coated cover is greatly simplified is that the risk is greatly reduced that an edge of a part of the coating prematurely with a part of another coating part comes into contact while the coating is being applied to the core. Premature contact with the edges the fungus often means that the wrong parts come into contact with each other, and so a wrinkling and an insufficient one Covering the pole can be. With the help of this preferred Embodiment of the invention, the mushrooms can be brought exactly into their respective position on the core, and then after The edges can be removed from the frame that defines the ifaht depressed and brought into contact with each other.

An advantageous Porm of the frame that defines the seam

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to which the coating is applied in two separate, substantially equal parts, is a metal frame made up of two parts (Other materials, e.g. plastics, can also be used). Each part of the frame corresponds to two half mushrooms (having the arrangement they assume when in position around a spherical core), one Side of each frame part corresponds to half a mushroom separated along its major axis, and the other side to one corresponds to half a mushroom separated along its minor axis. Instead of being flat, the frame is therefore shaped that it lies around a spherical core and with this is in contact. Therefore, when the two parts of the frame are in place on the core, delimit and separate they put together the two surfaces on which the two mushrooms are applied will. An alternative form of this frame is one in which the frame is divided into four parts, which when they are composed, which delimit two areas for receiving the mushrooms. In this case, the two sides of each frame part correspond to a quarter of the circumference of a felt.

The base of the frame, i.e. the part that contacts the core, can have a splash or lip on each side. on in this way a lip can run around the perimeter of any surface defining the felt. The edge of the felt is then on this lip lie when the felt is brought to the surface area of the core that is delimited by the frame «The the frame defining the seam is removed after the felt has been brought into contact with the core, and the edges of the Felts can then be pressed into abutting and adhesive contact with one another and with the core.

If desired, the entire surface of each felt can be pressed into contact with the core. However, it has turned into found in practice that in many cases a sufficient

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■ the adherence of the coating to the core can be achieved by is pressed only along the center line, i.e. the major axis, and along the edges of each felt. If the air pressure then is slackened, the core has a tendency to return to its original size, and this expansion effect may be sufficient to press the cladding and core together sufficiently, and may also have gaps in the Smooth the coating.

The device by which the coating is applied to the core depends on the number of pieces in which the coating is applied. Therefore, if the coating in two the same Parts, e.g. mushrooms, is applied, then two identical application devices or carriers can be advantageously used Way to be used. Each application device or each carrier preferably has a flexible base part on which the Mushroom is carried, and means by which the flexible base containing the mushroom can be bent around the core. It is preferred to bend the mushroom into an arcuate shape before contacting a substantial area of the kernel is brought. A very convenient method is to bring the central part of a mushroom into contact with a pole face of the To bring the kernel, and then bend the mushroom into a curved porm that encloses the corresponding part of the kernel, however not touched. The remaining areas of the mushroom can then be pressed into contact with the core. This procedure diminishes the risk of cracks in the coating. The means for bending the mushroom around the core can for example consist of pushrods, Cams or consist of the fact that the core is pressed against the central area of the mushroom or vice versa, so that this middle area moves out of the original plane of the mushroom. This latter means can e.g. be achieved that a generally U-shaped tool ■ is provided in which the tips of the arms of the U in contact be brought to the surface of the support base that sioh the

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opposite the mushroom-bearing surface. The tips of the arms of the U should be on either side of the central area the support base, i.e. the center of the support base should be between the tips of the arms of the U. The core can then be pressed against the center of the mushroom so that the mushroom and support base are pressed down against the bottom of the U. will. The ends of the mushroom and base are held back by the tips of the arms of the U, and therefore the desired curved porm of the mushroom can be achieved. When the arms of the U are sufficiently wide, it will be coated with glue Do not touch the surface of the mushroom to the core during this movement and only the contact surface will be on and close to it to be in the middle part of the mushroom. If the desired surface area of the core then through the curved Porm of the mushroom is trapped, the rest of the mushroom can be squeezed into contact with the core.

Each carrier can be enclosed in a chamber such as a cylinder that can be pressurized. When the carrier chambers are in position to remove the mushroom When attached to the core, they form part of a pressurizable area around the core. Therefore, if the core and the Carriers are in place, the pressure is increased, and the mushrooms are then placed on the core with reduced dimensions upset.

The amount of pressure required to shrink any particular core sufficiently is, of course, determined by depend on the type of core material and its wall thickness. Appropriate pressures to suit a typical tennis ball core

ty

for example, are about 0.7 to 2.8 kg / cm (10 to 40 psi) above atmospheric pressure and of course change accordingly the amount of overpressure in the ball core, if any.

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In the following, an embodiment of the invention will be explained in more detail with reference to the accompanying drawing.

Fig. 1 shows a view "with parts broken away, one of a pair of mushroom applicators or felt supports (ie. for applying cover parts).

PIg. Fig. 2 schematically shows a core to be coated, the core being held in a four-part frame defining the suture, and shows the push rods whose puncture is to push the fungus into contact with the core.

PIg. Figure 5 is a top plan view of the arrangement shown in Pig. 2 is shown, ie the frame encloses the core and the push rods are in the outer position.

Pig. Figure 4 is a top plan view of a corresponding arrangement when the frame is in the external position and the push rods have been moved into contact with the core after the mushrooms have been applied.

Pig. Figure 5 is a view of the mushroom application chamber, with parts broken away, with the two felt applicators in place on opposite sides of a core to be coated.

6 shows schematically the desired relative position of the two

Mushrooms in relation to each other and to the core.

This embodiment provides an apparatus and method for applying a coating in the form of two im essentially the same felts on a tennis ball core.

The device has two pressure cylinders 10, each of which contains a mushroom applicator or a felt carrier 11, such as these are referred to below.

The device also includes means for bringing the core into the felt cover chamber. The core is here in one

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the seam-defining frame was kept as it was later completely ". Means are also provided for the two. Pressure cylinders containing the filled mushroom carriers, i.e. with a felt in place in each, into their position in the mushroom application chamber. These different Transport means, not shown, are suitably conventional cams and gear mechanisms. If the. two mushrooms are in position adjacent to the core in the mushroom application chamber, they are adjacent in a planar arrangement to opposite poles of the core and their major axes are substantially perpendicular to one another.

Each mushroom carrier 11 (Pig. 1) has a flexible base 12 of im. essential to the size and shape of the mushroom, although this is not is essential, and on this basis the mushroom lies with its adhesive-coated surface facing upwards. A . The punched mushroom piece 13 with its adhesive-coated surface 14 facing up is in Pig. 1 shown immediately before it is arranged on the mushroom carrier 11. The base 12 is surrounded by a dumbbell-shaped frame 15 which delimits the base and thereby helps to bring the fungus into its position on it. However, this frame 15 is not connected to the base 12. The mushroom is suitably in its position by Pins 27 held «The frame is attached to the forks 16 of two Y-shaped brackets 17 and 18, and the other end 19, 20 of each bracket is slidably mounted on or near the end of a first rod 21 axially in the cylinder 10 runs. The support base 12 is attached at its center to one end of a spring-loaded second rod 29 which is coaxial with the first rod 21 to which the frame brackets are attached, and into and out of the end thereof is, the inward movement takes place against the action of the peder 29a. The second rod 29 and the bracket 17,18 are connected in the first rod 21 so that the movement of the second rod into and out of the first rod

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corresponding movement of the bracket and therefore of the frame 15 "causes .. Bas end of the rod 21 1st In the shape of a U-f9rmJ.gen leils 22, the arms 23,24 des'Vsich at the same distance from the second rod 29, and the latter entering the first rod 21 in the middle of the bottom of the U The tips of the arms of the TT carry rollers 23a, 24a. These rollers lie in the track 28, which in the underside of the support base 12, i.e. in the face opposite that on which the felt is worn. The arms of the U are rotatable in height from its base on pivot pins 25,26 stored so that they can be pushed inward when desired.

To apply a cover, a core 30 is placed in the felt application chamber and through a seam defining Frame 31 included and contained in this. The core held by this frame is shown in FIG.

The frame 31 which determines the seam consists of four interlocking parts. 32,33,34 and 35 together round about Core 30 interlock and delimit two dumbbell-shaped flecks 36 and 37 on the surface of the core to create dl · svel felts to record. Each frame part 32,33 »34 and 35 is attached to one slidable rod 38,39,40 or 41, with the help of which it can be guided into and out of contact with the nucleus. A lip 46 runs along the base of each side of the seam defining frame portion so that a continuous lip is formed around the circumference of the two areas 36 and 37 of the core.

Four pressure rods 42, 43, 44 and 45, the function of which will be described in detail later, are provided - as shown - to to press the felts into contact with the core · The Jfaöfv everyone "Druok bar is with a protruding edge 47,48,49 or 50 * provided, the edges being shaped to fit the circumference

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ORIGINAL INSPECTED

correspond to the end parts of a felt. The edges of these marginal, the are shaped so that they correspond to the lips 46 of the frame 31. Fig. 3 shows in plan view the position where the core is held by the frame that determines the seam, and the push rods are in the retracted or outer position, *

The core 30 to be coated is placed in the felt application chamber 51 (Fig. 5) and held in place by the frame 31 defining the seam. Two printing cylinders 10a and 10b, such as 5 are on opposite sides of the chamber 51 in sealing contact therewith. the Cylinders are arranged with respect to one another so that the felts they carry have their major axes perpendicular to one another lie. The operation of this arrangement is shown schematically in Fig. 6, where the two felts 13a and 13b somewhat are shown displaced from the core 30 but showing the relative arrangement they assume when with eggs Come into contact with the core. The chamber 51 and the cylinders 10a and 10b may be pressurized through air inlet 52 with air or other gas.

An adhesive-coated felt 13 is placed with its adhesive surface facing up on the base 12 of each felt support 11, as shown in FIG. Each carrier 11 is brought into the felt application chamber in its cylinder 10, and the Air pressure in the chamber 51 is increased to reduce the core size. Opposite poles of the core 30 are respectively in contact with the central areas of one felt, i.e. the area of the felt immediately above the second Rod 29 of each beam. The carrier and core are pressed further into contact so that the carrier base 12 and the felt pressed into a curved shape in the arms of the U 22. The rod 29 is forcibly moved in this position to Calibrate to move further into the first rod 21 against the pressure of the spring 29a, and this movement also causes a corresponding movement of the X-BfclgeX 17, 18 and of the carrier frame 15 »In

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in this position the core 30 is essentially in the arc Every mushroom included, but only in contact with the mushroom in its central area. The arms 25 »24 each U are then pushed inward by an opposing pair of push rods 42,43,44 and 45 to more of to bring the fungus into contact with the core. As described above was, the pressure rods are each surrounded by a protruding edge 47, 48, 49 and 50, respectively, these edges are shaped so that they are the end portions of the perimeter of a mushroom correspond. Each protruding edge can then be pressed into contact with the corresponding mushroom so that the perimeter of the end of each mushroom is pressed into contact with the core. This arrangement is particularly useful when at each end of the mushroom is above the tip of its arm of the U, i.e. when the distance between the tips of the U is less than that Length of a mushroom is. This arrangement is preferred as it reduces the risk of premature contact between the fungus and the core decreased during the bending of the mushroom.

As described above, therefore, the edges of the protruding edges 47, 48, 49 and 50 of the push rods are shaped to correspond to the lips 46 of the base of the frame 31 defining the seam. When the protruding edges are pressed into contact with the mushrooms, the four parts 32,33,34 and 35 of the seam defining frame 31 are withdrawn and the edges of the protruding edges are used to contact the edges of the ends of the mushrooms to press with the core (Pig. 4).

The pressure in chamber 51 is then released, and the core returns to its normal size. This expansion irons out gaps and provides the necessary, everywhere effective pressing, when the ball applies the pressure to itself and squeezes the protruding edges. An additional Anpreßsobrü. 1; can be added if required to make a

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to ensure uniform adhesion, in particular of the felt edges, to the core. For example, the frame defining the seam can be be brought back into contact with the now coated core so that it presses against the edges of the felts. Under normal conditions, the frame that governs has is brought back into contact again to be called a Holding mechanism to act while the device opens, so that the coated core, i.e. the mushroom covered ball, can be discharged from the device.

The coated core is removed from the mushroom application chamber and then, if desired, a final molding step be subjected to cure the adhesive and solidify the 'coating on the core.

It is advantageous that the device can be constructed in such a way that that it operates continuously so that the kernels and pairs of mushrooms are continuously in their respective holders and Carriers are brought and carried into the mushroom application chamber immediately after removal of the coated core.

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Claims (14)

Claims Process for applying a coating to a core, characterized in that the external dimensions of the core can be reduced by applying an external pressure that the coating on the reduced Core is applied, and that the pressure is then released so that the core is essentially its returns to its original size. 2. The method according to claim 1, characterized in that the external pressure is exerted with the aid of compressed air will. 3. The method according to claim 1 or 2, characterized in that the coating is applied in at least two pieces. 4. The method according to claim 1, 2 or 3, characterized in that that the core is a tennis ball core, and the cover in two separate, essentially the same, dumbbell-shaped Pieces is applied. 5. The method according to claim 4, characterized in that each coating piece is applied to the core that its larger axis lies on a great circle of the nucleus, and that the two great circles that form the two overhanging pieces correspond, lie in planes which are substantially perpendicular to each other. 6.. Device for applying a coating to a core according to a method according to any one of the preceding claims, characterized by a holder for the Ksrn, the 209840/1015 is contained in a coating application chamber, by a Applicator to place the coating on the core and by a source of compressed Air communicable with the coating application chamber. 7. Apparatus according to claim 6, characterized in that the holder has a first holder on which the core is conveyed into the chamber, and a second holder in the In the form of a frame in which the core can be clamped. 8. Apparatus according to claim 7, characterized in that the frame, the surface areas of the core which the various Pieces of the coating correspond, separate and. limited. 9. Apparatus according to claim 8, characterized in that the frame is a four-piece metal frame, the four pieces being shaped to be spherical around one Core come into engagement with one another that they divide the surface of the core into two dumbbell-shaped areas share. 10. Device according to one of claims 6 to 9, characterized in that that the applicator to bring the coating in place on the core is generally a U-shaped tool in which the tips of the arms of the U can be brought against the side of the Pressing the coating opposite the side that will be applied to the core. 11. The device according to claim 10, characterized in that the arms of the U are pivotably connected to the base of the TJ so that they can be pushed inwards. 209840 / IOiS 12 «Device according to claim 11, characterized in that that a pair of push rods is provided which can push against the arms of the U. 13. The device according to claim 10, 11 or 12, characterized in that that the application device additionally comprises a flexible carrier with a shape that a covering piece with the support slidably attached to the tips of the arms of the U. 14. The device can / ground according to any one of claims 10 to 13, characterized in that the applicator is contained in a cylinder which v brought into pressure-tight contact with the Überzugaufbringkammer ^1. 2098AO / 101S