Patent Description:
Earlier, weightlifting discs were made as solid metal disc plates, but nowadays weightlifting discs normally are made of a soft material like rubber or other elastomeric material with a central hub. Competition weights as well as training discs are normally made of rubber or other elastomeric compositions with high durability and are provided with a metal hub. The elastomeric (soft) material is used to absorb the shock and deceleration when a weightlifter drops or bumps the weights against the floor, which results in a better sound dampening and shock absorption. The metal hub provides a longer lifetime of the weight disc since there is deformation (tensioning) of the soft material around the center hole of the disc when dropped on the floor repeatedly.

The metal hub is of course positive for the lifetime of the disc, but yet there is a problem with the strength of the weight disc over time. One problem with these "soft" discs with a metal hub (or other hard material) is that the available area for distribution of a shock force between the metal hub and the surrounding softer disc, when the barbell with the weight disc is dropped on the floor, is limited to the interaction surface between the hub and the disc. This means that a great impact force acts on a small area of the soft weightlifting disc material which results in a tension peak at the impact area and a local deformation of the material, which is negative for the lifetime of the weightlifting disc. Over time, this also results in a gap between the hub and the disc part. To overcome this problem, a reinforcing device may be introduced into the elastomeric material. Such a solution is presented in <CIT>, where a reinforcing device is arranged into the elastomeric disc part, circumferentially around the center of the of the disc part, at a distance from the inner edge of the disc part such as elastomeric material is arranged between an inner edge of the disc part and the reinforcing device. Disadvantages with this solution are that the reinforcement device is small and has a small contact area towards the elastomeric material, wherein the reinforcing function is limited and the available area for distribution of a shock force between the reinforcing device and the surrounding elastomeric disc material is limited to the small interaction surface between the reinforcement device and the disc material.

Thus, there is a need of an improved strength of a weightlifting disc to lengthen the lifetime of a weightlifting disc of elastomeric material.

It is an object of the invention to address at least some of the problems and issues outlined above. It is possible to achieve these objects and others by a weightlifting disc as defined in the attached claims.

According to an aspect of the invention, a reinforced weightlifting disc to be arranged on a bar is disclosed. The weightlifting disc comprises a disc part of elastomeric material, wherein the disc part comprises an outer edge and an inner edge, wherein the inner edge is arranged close to a center of the disc part and the outer edge of the disc part is distal from the center of the disc part. The weightlifting disc further comprises at least one reinforcing device, arranged into the disc part circumferentially around the center, between the outer edge and the inner edge of the disc part, wherein the reinforcing device is arranged at a distance from the inner edge of the disc part such as elastomeric material is arranged between the inner edge of the disc part and the reinforcing device.

By this design, an impact force transferred from the floor via the disc part to the bar, is spread out over a large area via the circumferentially arranged reinforcing device. Further, by that the reinforcing device is arranged into the disc part at a distance from the inner edge (radially seen) such as elastomeric material is arranged between the inner edge and the reinforcing device, a dampening effect is disclosed as well as that the impact force in a certain part/direction is distributed to a larger area of the reinforcing device and further to the disc part before it reaches the bar. The risk of crack formation in the elastomeric material (rubber) is significantly reduced due to the force distribution and the risk of an increase of the gap between a hub part (if applicable) and the elastomeric disc part is significantly reduced. By that, the form of the disc is kept over time and tests show that the lifetime of the weightlifting disc of elastomeric material is significantly lengthened. Another aspect is that the individual disc part may be thinner such as more discs may be applied on the bar. No prior art solution provides a weightlifting disc with all these advantages. Further, the reinforcing device comprises spaced holes arranged to accommodate elastomeric material of the disc part. By having a number of holes distributed around the reinforcing device, which holes are arranged to accommodate elastomeric material, the transfer area available for distributing and take care of an impact force via the reinforcing device and disc part is greatly increased compared to a solid reinforcing device. Further, the reinforcing device gets good contact with the elastomeric material without the need of any pretreatment of the surfaces of the reinforcing device, which normally is needed when for example moulding different materials together, like metal and rubber for example.

According to an embodiment, the reinforcing device is substantially ring-shaped. Such a solution provides a good distribution of impact forces between the disc part and the bar, wherein the forces are circumferentially distributed around substantially the whole disc part, i.e. in all directions before the transfer to the bar.

According to an embodiment, the weightlifting disc further comprises a hub part arranged at the center of the disc part, wherein the disc part substantially surrounds the hub part when the hub part is arranged at the center of the disc part. The hub part is arranged to be attached at the inner edge of the disc part, and the hub part comprises a center hole for receiving a bar. A hub part, preferably made of metal, provides a complement to the reinforcing device because it also provides a transfer of an impact force from the disc part, via the hub part and further to the bar. Since there is elastomeric material between the inner edge of the disc part and the reinforcing device, there is elastomeric material between the reinforcing material and the hub part, which is positive as described above. The hub part may also be attach to the sides of the disc part, at least close to the inner edge of the disc part, which means that the hub part may serve both as a sleeve through the weightlifting disc, arranged to be in contact with the bar, by the attachment to the inner edge, and further as a reinforcement due to the contact with a part of the sides around the center of the disc.

According to an embodiment, the inner edge of the disc part comprises at least a protruding part which protrudes radially towards the center of the disc part, wherein the protruding part is arranged to be attached to the hub part. The protruding part is arranged as a protruding lip which is arranged around the inner edge of the disc part and thus extends towards the center of the weightlifting disc. The protruding part increases the distance between the reinforcing device and the inner edge of the disc part and if a hub is arranged at the inner edge, it increases the transferring area between the hub part and the disc part and provides a good fixation between the disc part and the hub part since the protruding part may be pressed between the two halves of the hub part, if the hub part is designed in that way.

According to an embodiment, the reinforcing device is made of metal. Preferably the metal is cast iron, which is a robust material well suited for the purpose, but other materials like steel, light metals like aluminium or the like may be used.

According to an embodiment, the reinforcing device is made of plastic. A plastic material provides a cost efficient solution for providing a reinforced weightlifting disc.

According to an embodiment, the reinforcing device and the disc part are moulded together to a unit such as the elastomeric material of the disc part encloses the reinforcing device.

In yet an embodiment, the hub part comprises two halves connectable to each other, wherein at least the inner edge of the disc part is arranged to be pressed between the two halves of the hub part when they are connected to each other. Such a solution is very good since the two halves so to speak clamps the disc part (and the protruding part if applicable) from both sides whereby a solid and robust attachment of the hub part is achieved as well as large area for transfer of the sudden impact force from a drop of the barbell with the assembled weightlifting discs. The two halves may preferably extend radially a distance from the center, which is enough to "enclose" at least a part of the disc part in which the reinforcing device is arranged, which by that is arranged with at least a part (nearest the inner edge) between the two halves.

According to an embodiment, the reinforcing device comprises a substantially cylindrical inner ring, a substantially cylindrical outer ring and an annular body connecting the inner ring and the outer ring. The reinforcing device looks more or less like a rim of a wheel, wherein the rings and annular body may have equal or different widths. For example, the outer ring may be wider than the inner ring or vice versa and the annular body may be thinner or wider than the outer ring and/or the inner ring. If the reinforcing device comprises holes, these may be arranged in any of the inner ring, the outer ring and the annular body. The ring-shaped reinforcing device is easy to manufacture the continuous ring-shape is very good for taking care of the impact force and distribute it along the reinforcing device and further to the disc part.

According to an embodiment, the annular body of the reinforcing device comprises a plurality of holes circumferentially distributed along the annular body and transverse the annular body. The holes are arranged to accommodate the elastomeric material of the disc part, and since the weightlifting device preferably is produced by moulding the reinforcing device and the disc part together to one unit, the reinforcing device transfers a shock force very well to the elastomeric material and over a large area, which is very positive for the lifetime of the weightlifting disc By that the holes are filled with elastomeric disc material, the material in the holes act as transverse beams in cooperation with the reinforcing device. The solution is very strong compared to prior art solutions. The holes are also positive since the reinforcing device do not need any pretreatment to make it stick to the elastomeric material, which otherwise would be needed.

According to an alternative embodiment compared to the one above, the annular body of the reinforcing device comprises a plurality of partitions extending between the inner ring and the outer ring, wherein the plurality of partitions together or with at least one of the inner ring or the outer ring forms the holes of the reinforcing device. In this embodiment, the annular body looks and function like a framework connected to the inner and outer ring.

According to an embodiment, the hub part comprises an insert arranged in the center hole of the hub part. The insert may be in plastic or in metal, but most preferred is a plastic insert. The insert acts as a vibration dampener and a silencer between the bar and the hub and the insert may be moulded to the hub/hub parts or may be a loose or pressed in place in the hub.

Further possible features and benefits of this solution will become apparent from the detailed description below.

Briefly described, an improved weightlifting disc of elastomeric material and comprising a reinforcing device, is disclosed.

<FIG> shows an exploded view of a weightlifting disc <NUM> according to the invention. The weightlifting disc <NUM>, which not necessarily but more preferred is a circular disc, comprises a disc part <NUM> made of elastomeric material, preferably a rubber material or the like. The disc part <NUM> comprises an outer edge <NUM> and an inner edge <NUM>, wherein the inner edge <NUM> is arranged close to a center <NUM> of the disc part <NUM> and the outer edge <NUM> of the disc part <NUM> is distal from the center <NUM> of the disc part <NUM>.

The preferred embodiment of the weightlifting disc <NUM> further comprises a hub part <NUM> which comprises a first half 30a and a second half 30b. The hub part <NUM> is to be arranged at the center <NUM> of the disc part <NUM>, such as the disc part <NUM> substantially surrounds the hub part <NUM> when the hub part <NUM> is arranged at the center <NUM> of the disc part <NUM>. The hub part <NUM> is arranged to be attached at the inner edge <NUM> of the disc part <NUM>, and the hub part <NUM> comprises a center hole <NUM> arranged for receiving a bar. The a first half 30a and a second half 30b of the hub <NUM> are connectable to each other, wherein at least the inner edge <NUM> of the disc part <NUM> is arranged to be pressed between the first and the second halves 30a, 30b of the hub part <NUM> when they are connected to each other. The first half 30a and a second half 30b are preferably fixedly connected to each other by means of screws <NUM>. The hub part <NUM> may comprise an insert <NUM>, which is to be arranged at the center hole <NUM> of the hub part <NUM>. The insert <NUM> is arranged as a vibration dampener and a silencer between the bar and the hub <NUM> and the insert <NUM> may be moulded to the hub/halves 30a, 30b or may be a loose or pressed in place in the hub <NUM>.

<FIG> is a front view of the complete weightlifting disc <NUM> comprising the hub part <NUM>, arranged at the center <NUM> of the disc part <NUM>. The outer edge <NUM> may normally have a flat or rounded surface. <FIG> is a section view at the center of the weightlifting disc <NUM>, indicated by the dotted line and arrows. <FIG> is a front view and <FIG> is a section view of the insert <NUM> mentioned above. <FIG> is a section view and <FIG> is a front view of the first half 31a of the hub part <NUM> and <FIG> is a front view and <FIG> is a section view of a second half 30b of a hub part <NUM>.

As can be seen in <FIG> the first and second halves 30a, 30b of the hub part <NUM> are mounted to the disc part <NUM> from a respective side of the disc part <NUM> and are fixedly attached to each other by screws <NUM>, which are screwed from the first half 30a in direction to the second half 30b of the hub part <NUM>. The insert <NUM> is in this embodiment a plastic cylinder fitted in the center hole <NUM> of the hub part <NUM>. A reinforcing device <NUM> is arranged into the disc part <NUM>, circumferentially around the center <NUM> of the disc part <NUM>, between the outer edge <NUM> and the inner edge <NUM> of the disc part <NUM>. The reinforcing device <NUM> and the disc part <NUM> are moulded together to a unit such as the elastomeric material (rubber) of the disc part <NUM> encloses the reinforcing device <NUM>, such as the reinforcing device <NUM> is totally enclosed into the elastomeric material. For further information about the reinforcing device, please see description below relating to <FIG> and <FIG>.

The insert <NUM> preferably is a plastic cylinder like the insert <NUM> visible in <FIG>. According to an alternative embodiment the insert <NUM> may have an outer flange (see <FIG>) which flange then extends radially outwards a short distance from the cylinder body and by that rests at an outside of the halves 30a, 30b of the hub part <NUM>.

The first and second halves 30a, 30b of the hub part <NUM>, which are visible in <FIG>, preferably are disc-shaped metal hubs with a center hole <NUM>, which halves as mentioned above, are connectable to each other on opposite sides of the disc part <NUM>, such as the inner edge <NUM> of the disc part <NUM> is pressed between the first and the second halves 30a, 30b of the hub part <NUM> when they are connected to each other. The halves 30a, 30b are preferably screwed together by screws <NUM>.

<FIG> is a side view of the disc part <NUM> and <FIG> is a section view of the disc part <NUM> of <FIG> in a section indicated by the dotted line and arrows. In the figures, the hub part <NUM> is not assembled to the disc part <NUM>. As can be seen in the section in <FIG> the reinforcing device <NUM> is arranged circumferentially around the center <NUM> of the disc part <NUM>, between the outer edge <NUM> and the inner edge <NUM> of the disc part <NUM>, such as the reinforcing device <NUM> is totally enclosed into the elastomeric material of the disc part <NUM>. As mentioned above, the reinforcing device <NUM> and the disc part <NUM> are moulded together to one unit. The inner edge <NUM> of the disc part <NUM> comprises a protruding part 12a, which protrudes radially towards the center <NUM> of the disc part <NUM>, and the protruding part 12a is arranged to be attached to the hub part <NUM>, i.e. the protruding part 12a is to be pressed between the first and second half 30a, 30b of the hub part <NUM>, when the hub part <NUM> is mounted to the center <NUM> of the disc part <NUM>, which may be seen in <FIG>.

<FIG> show the reinforcing device <NUM> in a side view respective a section view along the dotted line and indicated by the arrows in <FIG>. The reinforcing device <NUM> according to this preferred embodiment is ring-shaped and comprises a cylindrical inner ring <NUM>, a cylindrical outer ring <NUM> and an annular body <NUM>, which connects the inner ring <NUM> and the outer ring <NUM>. In the preferred embodiment, the outer ring <NUM> is slightly wider than the inner ring <NUM> and the annular body <NUM> has a tapered extension from the wider outer ring <NUM> to the narrower inner ring <NUM>. The annular body <NUM> of the reinforcing device <NUM> comprises a plurality of holes <NUM> circumferentially distributed spaced apart along the circular extension of the annular body <NUM> and which holes <NUM> are transverse relative the annular body <NUM>. The holes <NUM> are arranged to accommodate elastomeric material of the disc part <NUM> such as, when the reinforcing device <NUM> and the disc part <NUM> are moulded to one piece, the elastomeric material fills the holes <NUM>. By that, the total contact area between the elastomeric material of the disc part <NUM> and the reinforcing device <NUM> is very large, and the area for transferring impact forces between the disc part <NUM> and the reinforcing device <NUM> is thereby large. When moulding elastomeric material like rubber and incorporating another material into the mould, like the reinforcing device <NUM>, the surface of the incorporated material normally must be pretreated to get a "grip" between the incorporated device and the rubber, but because of the transverse holes <NUM> in the annular body <NUM> of the reinforcing device <NUM>, this is not necessary since the holes <NUM> provide a very good grip such as the reinforcing device <NUM> stays into the mould and "grips" the elastomeric material (rubber) in a very god way. Further, the ring-shape of the reinforcing device <NUM>, with the inner ring <NUM> and outer ring <NUM>, is very effective when taking care of impact forces since the "continuous" rings <NUM>, <NUM> distributes the force better compared to if the rings were not continuous. The reinforcing device <NUM> is preferably made of metal or of plastic material.

<FIG> is a side view of the weightlifting disc <NUM> of <FIG>. and <FIG> is a section view of the weightlifting disc <NUM> of <FIG> at a position indicated by the dotted line and arrows, and where the hub part <NUM> is assembled to disc part <NUM> of the weightlifting disc <NUM>. The section of <FIG> shows how the hub part <NUM> is arranged at the center <NUM> of the disc part <NUM>, such as the disc part <NUM> substantially surrounds the hub part <NUM>. As mentioned above, the hub part <NUM> comprises the center hole <NUM> arranged for receiving a bar and the first half 30a and the second half 30b of the hub <NUM> are connected to each other, wherein at least the protruding part of the inner edge <NUM> of the disc part <NUM> is pressed between the halves 30a, 30b of the hub part <NUM>. The hub part <NUM> is preferred to be a metal hub with a circular design and since the hub part <NUM> is in contact with the bar (not visible), the force from a drop of the barbell on the ground is transferred from the disc part <NUM> to the hub <NUM>. But due to the reinforcing device <NUM>, a substantial part of the force is transferred to the reinforcing device <NUM>, which distributes the force over a large area before it is transferred to the hub <NUM>, and the force at the contact surface between the hub part <NUM> and the bar by that is very low compared to if no reinforcing device would be arranged into the disc part <NUM>, as in prior art.

<FIG> is a zoomed section view of the hub part <NUM> of the weightlifting disc <NUM> with a first type of insert <NUM> mounted to the hub part <NUM>. The section shows how the holes <NUM> of the reinforcing device <NUM> is filled with the elastomeric material of the disc part <NUM>, and how the outer ring <NUM> and the inner ring <NUM> of the reinforcing device <NUM> is enclosed into the elastomeric material. The inner edge <NUM> of the disc part <NUM> is arranged such as the inner ring <NUM> of the reinforcing device <NUM> is arranged at a distance a from the inner edge <NUM> of the disc part <NUM>, such as elastomeric material is arranged between the inner edge <NUM> of the disc part <NUM> and the reinforcing device <NUM>. The first half 30a and the second half 30b of the hub part <NUM> are fixedly attached to each other by screws <NUM> such as the inner edge <NUM> and its protruding part 12a is pressed between the halves 30a, 30b, wherein the hub part <NUM> is very robust attached to the disc part <NUM> and wherein there is elastomeric material between the hub <NUM> and the reinforcing device <NUM>. The latter is shown to be very positive due to dampening characteristics and the total lifetime of the elastomeric weightlifting disc <NUM>. Further, the insert <NUM> in the form of the cylinder-shaped insert <NUM> presented in <FIG>, is attached in the center hole <NUM> of the hub part <NUM>. The insert <NUM> may be in plastic or in metal, but most preferred is a plastic insert <NUM>. The insert <NUM> acts as a vibration dampener and a silencer between the bar and the hub part <NUM> and the insert <NUM> may be moulded to the hub/hub parts 30a, 30b or may be a loose or pressed in place in the hub part <NUM>.

<FIG> is a zoomed section view of the hub part <NUM> of the weightlifting disc <NUM> with a second type of insert <NUM> mounted to the hub part <NUM>. This second type is an alternative insert <NUM> which has an outer flange which extends radially outwards a short distance from the cylinder body and by that rests at an outside of the respective halves 30a, 30b of the hub part <NUM>. The first and second halves 30a, 30b may be arranged with a recess to accommodate the flange of the insert <NUM> as may be seen in the figure.

<FIG> shows a front view of an alternative reinforcing device <NUM> and <FIG> shows a section view of the reinforcing device of <FIG>. This type has the same functionality as the one described above (<FIG>) and is also ring-shaped and comprises a cylindrical inner ring <NUM>, a cylindrical outer ring <NUM> and an annular body <NUM>, which connects the inner ring <NUM> and the outer ring <NUM>. In the preferred embodiment, the outer ring <NUM> is slightly wider than the inner ring <NUM> and the annular body <NUM> has a tapered extension, at least partly, from the wider outer ring <NUM> to the narrower inner ring <NUM>. The annular body <NUM> comprises a plurality of partitions 23a, which extends between the inner ring <NUM> and the outer ring <NUM> in different directions and thereby forms a "pattern", such as the plurality of partitions 23a together or with the inner ring <NUM> and/or the outer ring <NUM> forms the holes <NUM> of the reinforcing device <NUM>. The holes <NUM> have the same function as described above.

Although the description above contains a plurality of specificities, these should not be construed as limiting the scope of the concept described herein but as merely providing illustrations of some exemplifying embodiments of the described concept. It will be appreciated that the scope of the presently described concept fully encompasses other embodiments which may become obvious to those skilled in the art, and that the scope of the presently described concept is accordingly not to be limited. Reference to an element in the singular is not intended to mean "one and only one" unless explicitly so stated, but rather "one or more.

Claim 1:
A weightlifting disc (<NUM>) to be arranged on a bar, the weightlifting disc (<NUM>) comprising:
a disc part (<NUM>) of elastomeric material, wherein the disc part (<NUM>) comprises an outer edge (<NUM>) and an inner edge (<NUM>), wherein the inner edge (<NUM>) is arranged close to a center (<NUM>) of the disc part (<NUM>) and the outer edge (<NUM>) of the disc part (<NUM>) is distal from the center (<NUM>) of the disc part (<NUM>),
at least one reinforcing device (<NUM>), arranged into the disc part (<NUM>) circumferentially around the center (<NUM>), between the outer edge (<NUM>) and the inner edge (<NUM>) of the disc part (<NUM>), wherein the reinforcing device (<NUM>) is arranged at a distance (a) from the inner edge (<NUM>) of the disc part (<NUM>) such as elastomeric material is arranged between the inner edge (<NUM>) of the disc part (<NUM>) and the reinforcing device (<NUM>) characterized in that the reinforcing device (<NUM>) comprises spaced holes (<NUM>) arranged to accommodate elastomeric material of the disc part (<NUM>).