The invention relates to a disc shaped throwing object.

BACKGROUND Disc shaped throwing objects such as Frisbees™ are popular to use for recreational purposes.

There exist a variety of such disc shaped throwing objects of which one is shown in WO 2020/ 071973. This throwing object comprises an air cushion section joined to a rim. The rim comprises an inner surface and a sequence of curved contour sections with different curvatures.

This type of throwing object maybe soft and possible to fold. For small diameters of the object, this object has good aerodynamic properties. However, if the diameter is increased then the structure of the soft object may have difficulties in retaining its shape, which degrades the aerodynamic properties.

There is therefore a need for providing a soft throwing object that can have a large diameter while retaining good aerodynamic properties and foldability.

SUMMARY

The present invention addresses the problem of providing a soft throwing object with good aerodynamic properties that can be made with a large diameter while at the same time being foldable.

One aspect of the invention is concerned with a disc shaped throwing object comprising a soft disc having a central section and a rim as well as a resilient ring united with the rim, where the central section forms a disc centre through which a central axis is defined and which central section is joined to the rim, wherein the rim comprises a resilient ring having an untensioned state and a tensioned state, where the ring and rim radially encircle the central axis when the ring is in the untensioned state and the ring and rim are folded about the central axis when the ring is in the tensioned state.

The ring and rim may additionally be folded around a line that is perpendicular to the central axis when the ring is in the tensioned state. The ring may be placed in the rim, i.e. in the interior of the rim. As an alternative, if the rim comprises an inner surface radially displaced from the central axis forming or defining an inner cylindrical volume of the objec, the ring may be attached to this inner surface, for instance using glue.

The ring may be a metallic ring. However, also other materials are contemplated. When the ring is metallic, it may more particularly be made of a shape memory alloy striving to retain the untensioned state. Also the use of a spring is possible.

The weight of disc shaped throwing object including the ring maybe 19 - 31 times higher than the weight of the ring and with advantage 23 - 24 times higher than the weight of the ring. The weight of the disc shaped throwing object including the ring maybe in the range 80 - 200 g and with advantage 88 g, while the weight of the ring may be in the range 3.2 - 4.2 g and with advantage 3.7 g.

The ring may have a cross-section with a diameter in the range 0.4 - 2.0 mm with advantage of 1.0 mm.

The disc shaped throwing object may have a diameter of 150 - 300 mm and with advantage 210 mm.

The ring may additionally have an outer diameter in the range of 140 - 295 mm and with advantage of 203 mm. When in the tensioned state the ring and rim may be folded around a line that is perpendicular to the central axis. The disc may have a Shore D hardness of 40 - 90 and preferably of 50 - 70. The material of the disc may be an elastomer, such as silicone, rubber, a thermoplastic elastomer or a thermoplastic rubber.

The disc shaped throwing object may furthermore comprise a bridging section and the central section may be joined to the rim via the bridging section.

The thickness of the bridging section may decrease from the rim towards the central section.

Furthermore, the rim may comprise an inner surface radially displaced from the central axis and a sequence of curved contour sections. The inner surface of the rim may at one end be joined to an inner surface of the bridging section and at a second end to an outer surface of the bridging section via the contour sections, where the contour sections interconnect the inner surface of the rim with the outer surface of the bridging section via a first extreme radius placed at a maximum horizontal distance from the inner surface of the rim. The inner surface of the bridging section may have a first curvature and a last contour section in the sequence together with at least a part of the outer surface of the bridging section may have a second, different curvature. The curvatures may cause the thickness of the bridging section to decrease towards the central axis.

The rim may further comprise a second extreme radius placed at a maximum distance along the central axis from an outer surface of the disc centre.

The first curvature may be an exponential curvature starting from a starting radius on the inner surface of the rim and the second curvature may be a parabolic curvature starting from the first extreme radius.

It is in this case furthermore possible that the first curvature is formed as an exponential curve so that radial position changes on the first curvature starting from the starting radius on the inner surface of the rim are exponential for changes along the central axis in a direction towards an outer surface of the disc centre and that the second curvature is formed as a second degree polynomial curve, so that radial position changes on the second curvature starting from the first extreme radius are parabolic in the direction along the central axis towards the outer surface of the disc centre. It is in the above-mentioned case also possible that the starting radius on the inner surface of the rim is axially aligned with the first extreme radius.

The second extreme radius is thus no radius that is closest to or furthest away from the central axis, but a radius of the object that is axially furthest away from the outer surface of the disc centre. It is possible that the first extreme radius is placed closer to an axially highest radius of the rim than it is to the second extreme radius, where the axially highest radius of the rim may be the rim radius that is axially closest to the outer surface of the disc centre.

It is additionally possible that the second extreme radius is radially closer to the inner surface of the rim than it is to the first extreme radius.

The ring may be located between the first extreme radius and the second extreme radius in the axial direction. The ring may more particularly be located closer to the first extreme radius than the second extreme radius.

The contour sections may comprise a first curved contour section stretching from the inner surface of the rim to the second extreme radius, a second curved contour section stretching from the second extreme radius to an intermediate radius between the inner surface of the rim and the first extreme radius, a third curved contour section stretching from the intermediate radius to the first extreme radius and a fourth curved contour section that is the last curved contour section of the sequence.

In this case it is additionally possible that the first and second curved contour sections are parabolic starting from the second extreme radius so that axial position changes on these curvatures starting from the second extreme radius are parabolic for radial changes away from the second extreme radius. It is also possible that the third and fourth curved contour sections are parabolic starting from the first extreme radius so that radial position changes on these curvatures starting from the first extreme radius are parabolic for axial changes away from the first extreme radius. The curvatures of the first, second, third and fourth curved contour sections may for instance be curvatures with shapes as second-degree polynomial curves.

The rim may thereby also have an essentially ear shaped cross-section, even though other shapes are possible. It may for instance lack a point having a first extreme radius. It is furthermore possible that the curvature of the second curved contour section gradually transitions into the curvature of the third curved contour section around the intermediate radius.

According to another possible variation, the curvature of the second contour section is the same as the curvature of the first curved contour section in the vicinity of the second extreme radius and the curvature of the third contour section is the same as the curvature of the fourth contour section in the vicinity of the first extreme radius.

The central section may additionally have a first radius in relation to the central axis. It is additionally possible that the central section has a uniform thickness.

Yet another possibility is that the object has a thickness in the range of 10 - 14 mm, for instance 11 mm, which thickness may essentially be the thickness of the rim.

The invention has a number of advantages. It provides a soft throwing object with good aerodynamic properties that can be made with a large diameter while at the same time being foldable.

Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the element, apparatus, component, means, step, etc." are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated. BRIEF DESCRIPTION OF THE DRAWINGS

The invention is now described, by way of example, with reference to the accompanying drawings, in which:

Fig l shows a perspective view from above of a disc shaped throwing object, Fig. 2 shows a perspective view from below of the disc shaped throwing object,

Fig. 3 shows a top view of the disc shaped throwing object with indications of where a cross-section is taken,

Fig. 4 shows a cross-sectional view of the object taken at the cross-section indicated in fig. 3 and with a metallic resilient ring inserted in a rim of the object,

Fig. 5 schematically shows the ring,

Fig. 6 shows a first enlargement of a part of the cross-section with the rim and parts of a bridging section,

Fig. 7 shows a second enlargement with further details of the rim and bridging section,

Fig. 8a shows an exponential curve,

Fig. 8b shows a parabolic curve, and Fig. 9 shows the object being folded.

DETAILED DESCRIPTION The invention will now be described more fully hereinafter with reference to the accompanying drawings, in which certain embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout the description.

Fig l schematically shows a perspective view from above of a disc shaped throwing object io, fig. 2 schematically shows a perspective view from below of the disc shaped throwing object io, fig. 3 schematically shows a front view of the disc 11 of the object together with an indication A - A of where a cross- sectional view has been taken, fig. 4 shows a cross-sectional view of the object 10 taken at the cross-section A - A indicated in fig. 3, fig. 5 schematically shows a resilient metallic ring that is a part of the object 10, fig. 6 shows a first enlargement of a part of the cross-section showing a rim and parts of a bridging section and fig. 7 shows a second enlargement with further details of the rim and bridging section.

As can be seen in the above-mentioned figures the throwing object 10 is disc shaped and thus formed as a disc 11. As can be best been in fig. 4, the object comprises a central section 12 joined to a rim 16 via a bridging section 14. It can thereby also be seen that the bridging section 14 is joined to the rim 16. The bridging section 14 is here a first air cushion section and the central section is a second air cushion section. The sections are termed this way since in use both of them are supposed to be lifted by an air cushion. The central section 12 is cylindrical and may have a uniform thickness Ti corresponding to the height of the cylinder, that is furthermore solid. The thickness may in this case be in the range of 0.3 - 0.5 mm. As the central section 12 is shaped as a cylinder, there is also defined a central axis AX through the middle, i.e. through a centre point of this central section 12, and the section has a first radius Ri in relation to the central axis AX. This centre point is also the centre point of a disc centre.

It can also be seen that the bridging section 14 has an inner radius coinciding with the first radius Ri of the central section 12 and an outer radius R2 at which it is joined to the rim 16. As can be seen in the figures this bridging section does not have a uniform thickness, but instead a thickness that increases towards the rim 16 or decreases towards the central section 12.

The rim 16 in turn has a cross-section shaped as an ear, although other shapes are also contemplated. As may be best seen in fig. 4, the rim has an inner surface RIS at a distance from the central axis AX corresponding to the second radius R2 and, as may best be seen in fig. 6, a sequence of curved contour sections CSi, CS2, CS3, CS4.

The inner surface RIS of the rim 16 has the same distance R2 to the central axis AX. It is thereby curved around and surrounds and faces the central axis AX. The inner surface RIS thereby surrounds an inner cylindrical volume of the object 10 with radius R2 centred around the central axis AX. The rim thereby also defines an inner volume of the throwing object, which inner volume is the cylindrical volume. Moreover, the inner surface RIS is at a first end joined to an inner surface BSIS of the bridging section 14 and at a second end is joined to an outer surface BSOS of the bridging section 14 via the contour sections CSi, CS2, CS3 and CS4. Thereby, the first end is also joined to a flat inner surface CSIS of the central section 12 via the inner surface BSIS of the bridging section 14 and the second end is also joined to an outer surface CSOS of the central section 12 via the contour sections CSi, CS2, CS3 and CS4 and the outer surface BSOS of the bridging section 14. The inner surface of the bridging section will in the following be termed bridging section inner surface, the outer surface of the bridging section will be termed bridging section outer surface, the inner surface of the central section will be termed central section inner surface and the outer surface of the central section will be termed central section outer surface. Finally, the inner surface of the rim will be termed the rim inner surface.

Moreover, the contour sections CSi, CS2, CS3 and CS4 interconnect the rim inner surface RIS with the bridging section outer surface BSOS via a first extreme radius ERi placed at a maximum radial distance from the rim inner surface RIS. The first extreme radius ERi can thereby be considered to be an edge in the contour of the rim 16.

Furthermore, the bridging section inner surface BSIS has a first curvature and the last contour section CS4 in the sequence of contour sections together with at least a part of the bridging section outer surface BSOS has a second, different curvature, where the combination of these curvatures cause the thickness of the bridging section 14 to decrease towards the disc centre, which in this case is also towards the central section 12. Through having two curvatures in this way it is possible to optimize different aspects of the flying object independently of each other. The first curvature may as an example be designed in order to decrease very rapidly from the rim 16 towards the central section 12 in the neighbourhood of the rim and thereafter to decrease slowly, which maybe important if the weight of the throwing object 10 is to be lowered. At the same time the second curvature can be designed for other purposes, such as in order to achieve various aerodynamic goals.

One way in which two such curvatures may be obtained will now be described.

One example of a first curve Cl that is an exponential curve and that may be employed for forming the first curvature is shown in fig. 8a. One example of a second curve C2 that is a second-degree polynomial curve that may be employed for forming the second curvature is shown in fig. 8b. This second curve has an extreme point ES which is a minimum.

According to the variation of the invention shown in fig. 4, 6 and 7, the first curvature of the bridging section inner surface BSIS is formed as an exponential curve, such as the curve Cl in fig. 8a, so that radial position changes on the first curvature starting from a starting radius on the rim inner surface RIS are exponential for changes in the direction of the central axis AX towards the outer surface of the disc centre, which in this case is also towards the central section outer surface CSOS. This means that as the axial distance on the rim inner surface decreases in the axial direction from the starting radius SR towards the central section outer radius, the radial distance to the central axis AX decreases exponentially. The radius of the bridging section inner surface BSIS thus decreases exponentially with decreasing axial distances from the starting radius towards the central section outer radius CSOS. As can be seen in fig. 7, it is additionally possible that the starting radius SR is axially aligned with the first extreme radius ERi. They may thus be placed at essentially the same position along the axis AX.

The second curvature may instead be formed like a second degree polynomial curve, such as the curve C2 in fig. 8b, so that radial position changes on the second curvature starting from the first extreme radius ERi are parabolic for changes in the direction along the central axis AX towards the outer surface of the disc centre, which in this case is also towards the central section outer surface CSOS. This means that as an axial distance on the surface of the last contour section CS4 and the bridging section outer surface BSOS is decreased from the first extreme radius ERi towards the outer surface of the disc centre, which in this case is also towards the central section outer radius CSOS, the radial distance to the central axis AX decreases parabolically. The radius of the contour section CS4 and at least some parts of the bridging section outer surface BSOS thus decrease parabolically with decreasing axial distances from the first extreme radius ERi towards the outer surface of the disc centre, which in this case is also towards the central section outer surface CSOS. The curve may thus be a parabolic curve, such as that shown in fig 8b, where the first extreme radius ERi corresponds to an extreme point EP of such a curve C2, such as a maximum or a minimum. Moreover, the radius at which the transition from the last contour section CS4 of the rim 16 to the bridging section outer surface BSOS is made is an axially highest HR radius of the rim 16. The axially highest radius HR is thus the radius of the rim 16 that is axially closest to the outer surface of the disc centre, which in this case is also the central section outer surface CSOS. As can be seen in fig. 7, the rim 16 may also comprise a second extreme radius ER2. This extreme radius maybe placed at a maximum distance in the direction of the central axis AX away from the outer surface of the disc centre, which in this case is also away from the central section outer surface CSOS. The radius is thus no radius that is closest to or furthest away from the central axis AX, but a radius of the object that is axially furthest away from the outer surface of the disc centre, which is here the central section outer surface CSOS.

As mentioned earlier the rim 16 may comprise a sequence of contour sections. This sequence is a sequence according to which the contour sections are joined to each other. It can be seen in fig. h that the sequence comprises a first curved contour section CSi, a second curved contour section CS2, a third curved contour section CS3 and a fourth curved contour section CS4, which fourth curved contour section CS4 is the last curved contour section in the sequence. Alternatively, the fourth curved contour section CS4 may be considered to be the first in the sequence and the first CSi to be the last.

The first curved contour section CSi stretches from the rim inner surface RIS to the second extreme radius ER2, the second curved contour section CS2 stretches from the second extreme radius ER2 to an intermediate radius IR between the rim inner surface RIS and the first extreme radius ERi, the third curved contour section CS3 stretches from the intermediate radius IR to the first extreme radius ERi and the fourth curved contour section CS4 stretches from the first extreme radius ERi to the axially highest radius HR of the rim 16.

It can here be seen that the first and second curved contour sections CSi and CS2 have curvatures shaped as second-degree polynomial curves so that axial changes on these curvatures starting from the second extreme radius ER2 are parabolic for changes in the radial direction away from the second extreme radius ER2. The axial distance from the curved contour sections CSi and CS2 to the axially highest radius HR thereby decrease parabolically for changes in the radial direction away from the second extreme radius ER2. The curved sections may more particularly, at least initially, be curved according to the same parabolic curve. The first and second curved contour sections CSi and CS2 may thus be shaped according to the same second-degree polynomial curve. The curve may thus be a parabolic curve, such as that shown in fig 8b, where the second extreme radius ER.2 corresponds to the extreme point EP, such as a maximum or a minimum, and the first curved contour section may be shaped as a part of the curve on one side of the extreme point, while the second curved contour section may be at least partly shaped as a part of the curve on the other side of the extreme point ES.

The third and fourth curved contour sections CS3 and CS4 may likewise be formed as second-degree polynomial curves so that radial changes on these curvatures starting from the first extreme radius ESi are parabolic for axial changes away from the first extreme radius ERi. The radial distance from the curved contour sections CS3 and CS4 to the axis AX thereby decrease parabolically for changes in the axial direction away from the first extreme radius ERi. The curved contour sections may also here, at least initially, be curved according to the same parabolic curve. The third and fourth curved contour sections CS3 and CS4 may thus be shaped according to the same second-degree polynomial curve. The curve may thus be a parabolic curve, such as that shown in fig 8b, where the first extreme radius ERi corresponds to the extreme point EP, such as a maximum or a minimum, and the third curved contour section may be at least partly shaped as a part of the curve C2 on one side of the extreme point ES, while the fourth curved contour section may be shaped as a part of the curve on the other side of the extreme point ES.

As can also be seen in fig. 7, the curvature of the second curved contour section CS2 may gradually transition into the curvature of the third curved contour section CS3 around the intermediate radius IR. The second curved contour section CS2 may therefore only have the same curvature as the first curved contour section CSi in the vicinity of the second extreme radius ER2, while the third curved contour section CS3 may only have the same curvature as the fourth curved contour section CS4 in the vicinity of the first extreme radius ERi. One other observation that can be made in fig. 7 is that the first extreme radius ERi is placed closer to the axially highest radius HR of the rim 16 than it is to the second extreme radius ES2. It can also be seen that the second extreme radius ER2 is radially closer to the rim inner surface RIS than it is to the first extreme radius ERi.

The width W of the rim in the radial direction, i.e. between first extreme point ESi and the rim inner surface RIS, may be in the range 5 - 9 mm. It may with advantage have a width of 6.7 mm. The object may finally have a thickness in the range of 10 - 14 mm, for instance 11 mm, which thickness may essentially be the thickness of the rim 14.

The throwing object realized in this way has a very thin central section 12 and a bridging section 14 that quickly becomes very thin. Thereby it is possible to make the object lightweight. This improves the ability of the object 10 to stay long in the air. Through the design of the rim 16, the object can at the same time be firmly gripped and accurately thrown. The curved contour sections of the rim also gives the object good aerodynamic properties allowing a stable flight and makes the object less inclined to wobble in the air.

The disc shaped object 10 is typically made in one piece and it is with advantage also flexible, so that it can be folded. It can thereby be easily stowed away and carried around, such as in a pocket. It will because of this also be soft, which is good for avoiding injuries. The material of the disc may for this reason be an elastomer, such as silicone, Thermoplastic Elastomer (TPE), Thermoplastic Rubber (TPR) or rubber. It may additionally have a Shore D hardness of 40 - 90 and preferably of 50 - 70. The object may furthermore have a diameter in the range 150 - 300 mm and with advantage a diameter of 210 mm.

When the disc 11 of such a large throwing object is soft the object 10 may have problems in retaining its shape in the air. Thereby the aerodynamic properties will not be as good as when the object has smaller dimensions. As can be seen in fig. 4 and 7 the rim may be united with a ring 18, which ring in turn is shown in fig. 5. The ring is provided in order to improve the aerodynamic properties. For this reason, the rim maybe equipped with a cavity 20 in which the ring 18 is placed. The cavity may be sealed with a seal 22, which seal 22 is with advantage placed in the rim inner surface RIS in order to minimize the influences on the aerodynamical properties. It should be realized that as an alternative the rim maybe directly formed around the ring, in which case there would be no need for a cavity or a seal. As yet another alternative the ring may be joined with the inner surface of the rim, for instance using glue. In this case the ring may be placed in the inner cylindrical volume of the object defined by the rim 16.

The ring 18 may have an outer diameter in the range of 140 - 295 mm and with advantage 203 mm. The ring may additionally have a cross-section with a diameter in the range 0.4 - 2.0 mm and with advantage of 1.0 mm. The inner diameter maybe in the range 129.2 - 221.6 mm. The weight of disc shaped throwing object including the ring maybe 19 - 31 times higher than the weight of the ring and with advantage 23 - 24 times higher than the weight of the ring. The weight of the disc shaped throwing object including the ring maybe in the range 80 - 200 g and with advantage 88 g, while the weight of the ring may be in the range 3.2 - 4.2 g and with advantage 3.7 g

The ring may additionally be located between the first extreme radius ERi and the second extreme radius ER2 in the axial direction, where it may with advantage be placed closer to the first extreme radius ERi than the second extreme radius ER2 along this direction. Through this realization of the ring the aerodynamic properties of the throwing object are improved so that it can retain its desired shape in the air.

However, it is still desirable to be able to fold the throwing object.

In order to address this issue, the ring has an untensioned state and a tensioned state, where the ring and rim radially encircle the central axis AX when the ring is in the untensioned state and are folded about the central axis the ring is in the tensioned state. In the tensioned state the ring and rim may additionally be folded about a line perpendicular to the central axis AX. It is thereby possible for a user to put the ring in the tensioned state through applying forces to opposite halves of the object, which may be done through the use of the hand of the user and/or through placing the folded object in a pocket. As soon as these forces are no longer applied, the ring returns to its untensioned state and the object can be thrown.

In a preferred variation the ring is realized as a shape memory alloy striving to retain the untensioned state. In other realizations the ring may be realized using a spring that likewise strives to retain the untensioned state. The alloy may with advantage be a Nickel-Titanium alloy. The ring may therefore be metallic. It should however be realized that other materials are possible.

It can thereby be seen that it is possible to provide a large and soft throwing object with good aerodynamic properties that is at the same time foldable.

A soft and thin object has another advantage. When this object is flowing in the air, central parts around the central axis, such as the central section and parts of the bridging section, will be lifted higher by an air cushion than peripheral parts, such as the parts of the bridging section close to the rim. A bulge is thereby formed around the central axis. In this way the aerodynamic properties are further enhanced.

There are a number of variations that may be made to the invention apart from those already disclosed. It is for instance possible that there is no bridging section but only a central section. In this case it is possible that the central section has a varying thickness. It is also possible that the bridging section inner surface and the last contour section in the sequence of contour sections together with at least a part of the bridging section outer surface may have the same curvatures, which as an example may be exponential. The shape of the rim is also exemplifying. It does not have to be ear shaped. It may as an example have a radial outer surface essentially shaped in the same way as the radial inner suface.

The invention has mainly been described above with reference to a few embodiments. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the invention, as defined by the appended patent claims.