Patent Application
20210283957
Generally the present invention relates to tire inserts. Particularly, however not exclusively, the invention pertains to a tubeless tire anti-puncture insert for protecting the rim.
In general, tubeless tires are used on bicycles, motorcycles and cars. A common cause of a flat tire is puncturing of the tire by a sharp object. Another common cause of a flat tire is that the tire is left, as two layers, between the rim and the ground as the tire collapses at a high speed or in a falling movement. During the hard hit, the rim penetrates through the both layers of the tire, both the sidewall and the tread. Increasing the strength of the tire may reduce the risk of a flat tire but this increase in the strength of the tire leads to an increased rolling resistance (friction) and mass in the tire. A low rolling resistance and mass are very important in cycling since the bike mostly is driven by muscle power. A tire punctured between the rim and the ground poses a huge problem in mountain biking. The sidewalls of mountain-bike rims are very narrow, and, therefore, sharp in order to eliminate any excess mass.
The flat tire problem has been addressed in a variety of ways. The most common way to add a fluid added inside the tire, containing particles that harden with compressed air. As air tries to exit through a narrow hole in the punctured tire, the fluid, in a way, repairs the tire. However, this does not work well for cut-like holes. Another solution is to fit a smaller tire inside the tire, allowing more pressure to be introduced. As this smaller tire does not contact the sidewalls or the actual contact surface of the tire, it does not increase the rolling resistance. The pressures and the weight of the inner tire vary from 6 to 12 bar and approximately 120 to 200 g per tire, respectively. If the rim-facing side of the inner tire is open, it makes the rim weaker when pressurized because the air pressure compresses the rim. As the rim is compressed, the spoke tension decreases, and, consequently, the entire bike becomes less rigid. A tube tire is not open and allows much higher pressures to be used without decreasing the spoke tension. In order to inflate the inner tire, either a second hole or a separate fitting is needed, allowing air to be separately introduced into the two separate tires through the same hole. Besides, top racing cyclists have complained about that the inner tire causes a lack of shock absorption and, therefore, excessive bumping. Since pressures lower than two bar are usually used in the outer tires of mountain bikes, the outer tire requires, in addition, the above-mentioned fluid to tighten against the rim. The amount of fluid needed is approximately 60 g, resulting in an overall weight of almost 200 g per tire. None of these applications actually enters between the internal layers of the tire to absorb the force of a shock but the inner tires prevent the tire from totally collapsing under pressure. Thus, the use of inner tires does not provide a very good protection against hits in curve driving.
The most lightweight solution commonly used by hobby cyclists is a pipe insulation made of cellular plastic (approximately 60 g). The pipe insulation is formed into a loop by taping its ends together. The pipe insulation is fitted inside a tire, and, if the tire collapses, it possibly stays between the rim and the tire to absorb the shock. The pipe insulation being round and smaller than the diameter of the inside of the tire, it does not work reliably. If the diameter of the pipe insulation is equal to the inner diameter of the tire in size, it has an adverse effect on the operation of the tire and increases the rolling resistance.
A considerable number of different internal tire shield inserts intended to prevent rim damage are known from the prior art, one of them being presented by U.S. Pat. No. 3,949,796A. In this solution, a hard insert is fitted inside a tire to prevent the rim from hitting the ground. This solution corresponds to the above-mentioned inner tire solution. This solution would be too heavy and would impair the properties of the tire in curve driving, for instance.
The objective of the embodiments of the present invention is to at least alleviate one or more of the aforementioned drawbacks evident in the prior art. The objective technical problem of the present invention is how to solve a rim protecting tire insert that is lightweight and simple to install on conventional bicycle tubeless tires. Installing and replacing a tire, which is one of the most common problems of a cyclist, should be as effortless as possible and the installation of an insert in a conventional tire shouldn't add significantly to the tire changing process. Further, another objective technical problem is to create a solution that meets the previous conditions so that it does not require special arrangements from the tire or rim itself, but is suitable for conventional tire structures.
The objective can be achieved by means of a single, flat cellular-plastic loop that can be fitted inside a tire and that essentially extends, at the widest point of the tire, from sidewall to sidewall. If the tire collapses, the cellular plastic stays between the tire layers to absorb the force of the shock. The cellular plastic thus protects the tire and the rim from getting a sharp hit. Herein, the cellular plastic is presented as an example but other materials are feasible.
The invention aims at protecting a tire and rim while the tire collapses under a high pressure. The invention provides a solution that is lightweight, simple in structure and increases very little rolling resistance in comparison to the prior art.
The present invention has a further advantage of take up very little space of the tire's air space. The present invention provides a solution which is thin, allowing the tire air space to be maintained close to the original volume of the tire. The size of the air space in the tire has also an effect on how the tire may puncture. Smaller airspace requires higher pressures and therefore makes the tire more prone to puncture because the internal pressure tends to break the tire more easily than the smaller pressure at the point of impact. Even in terms of the tire's rolling characteristics, the optimum pressure is achieved better with the larger airspace. Thus, it is preferable that an insert reduces the tire's air space as little as possible.
In accordance with one aspect of the present invention an anti-puncture shield insert for a wheel, which wheel comprises a rim and an inflated tire connected to the edges of the rim,
wherein said anti-puncture shield insert is made of a shock-absorbing material, characterized in that said shield insert is placed at the widest point between the inner sidewalls of the tire, and, as a hit causes the tire to collapse, the shield insert absorbs the shock taken by the tire and the rim, by staying between inner parts of the tire, and, further, in that the shield insert is floating relative to the tire.
According to an exemplary embodiment of the present invention the anti-puncture shield insert for a wheel comprising an inflated tubeless tire. According to a preferred exemplary embodiment of the present invention the anti-puncture shield insert for a bicycle wheel. According to another exemplary embodiment of the present invention the anti-puncture shield insert for a motor vehicle wheel, such as the wheel of a motorbike or a car.
According to an exemplary embodiment of the present invention the anti-puncture shield insert comprises cellular plastic with cells that stretch and, when needed, burst as a result of a hit taken by the tire, by absorbing the energy of the shock, and, thereby, protecting the tire and rim.
According to an exemplary embodiment of the present invention the anti-puncture shield insert comprises cellular plastic that may be further coated with another material.
According to an exemplary embodiment of the present invention the anti-puncture shield insert may comprise a sandwich structure, which may comprise cellular plastic or other suitable honeycomb core wherein suitable skin material is laminated. A skin may be laminated on any one or more sides of the anti-puncture shield insert. Many feasible skin materials are known from the art.
According to an exemplary embodiment of the present invention the anti-puncture shield insert is removably inserted into the wheel. This allows the anti-puncture shield insert to be changed in case of breakage or wear caused by use.
According to an exemplary embodiment of the present invention the anti-puncture shield insert makes it easier to mount the tubeless tire on the rim by air pressure, by keeping the sidewalls of the tire apart and against the edges of the rim. In this embodiment the anti-puncture shield insert width is essentially the same as the tire maximum inner width.
As being appreciated by a skilled person, the anti-puncture shield insert is scalable in size within the physical limitations of the present invention, which allows for a variety of applications and freedom of design. Size and materials may be chosen in view of the preferred properties set by each application e.g. in terms of driving style, tire type and driving surface (e.g. terrain, soil or tarmac) type.
As briefly reviewed hereinbefore, the utility of the different aspects of the present invention arises from a plurality of issues depending on each particular embodiment.
The term “exemplary” refers herein to an example or example-like feature, not the sole or only preferable option.
The term “insert” is used to refer to the characteristic that the anti-puncture shield is removably situated inside the wheel, i.e. between the rim and tire of a vehicle. The term “shield” is used to refer to the purpose of the insert, which purpose is to shield the rim between the tire inner surface and the rim in case of puncture or shock to the tire that could cause a pinch flat.
In the following, the invention will be described in detail with reference to the accompanying figures showing some embodiments of the invention, wherein
The shield insert (40) is applicable to all bicycles or electrically assisted bicycles requiring a low rolling resistance and an additional shield for their tires. The embodiments of the
The shield insert (40) can be implemented in a number of different ways, but it is common for all of the implementations to place the shield insert (40) at the widest point of the tire (30), in a so-called floating manner, due to the fact that the shield insert (40) has a suitable outer dimensions. The dimensions of different tires (30) and rims (20) may vary to a great extent. As an example, the diameter of a tire (30) may vary from one inch to five inches, and, the inside width of a rim (20) may vary from twenty millimeters to fifty millimeters.
Further, the circumference length of the shield insert (40) is chosen in light of tire dimension such as that it fits inside the tire in a floating manner. The length of the shield insert (40) may be predetermined or it may be cut in to a specific measure or it may comprise a mechanical fastening device or component that allows for adjustment of the circumference. Further, any potential additional elements such as fastening means preferably reside in the middle of the shield insert (40) so that there is little risk for chafing or contact with the rim (20) and the inside of the tire (30).
Few examples of sizes in relation to 27.5″ and 29″ tire sizes comprise:
In accordance with the aforementioned dimensions and cellular foam structure the shield insert (40) weight approximately 70-100 grams, with certain thickness and/or groove structures in the shield insert (40). However, other types of materials, as well as overlays may be used. The shield insert (40) may also comprise a sandwich structure.
In view of the aforementioned, the width of the shield insert (40) is also chosen in accordance with the tire (30) and rim (20) width wherein the requirement is that the shield insert (40) width should always be greater than the rim (20). Hence, the shield insert (40) width is preferably such that it doesn't touch the inner sidewalls of the tire (30) but that it surpasses the width of the rim (20) as depicted in
Further, the shield according to the invention is useful since it makes it easier to mount a tubeless tire (30) on a rim (20) by air pressure. If the tire (30) and the rim (20) have different tolerances it can be difficult to mount the tire (30) on the rim (20) by air pressure. It has been found out that the anti-puncture shield insert (40) facilitates the mounting of the tire (30) on the rim (20) because it holds the edges of the tire (30) against the edges (21) of the rim. The shield insert (40) may be easily installed in the wheel (10) because the shield insert (40) isn't attached to either the rim (20) or tire (30) or any other structure in the wheel (10). Essentially, it is the geometrical dimensions (circumference and width) of the shield insert (40) that keeps the shield insert in the correct place in relation to the tire (30) and rim (20) of the wheel with the obvious notion that the tire (30) controls to an extent the position of the shield insert (40) between the tire (30) and the rim (20).
The shield (40) may comprise grooves, cut holes or cuts at the sides or through the middle of the shield (40), which may be used to reduce the weight and affect the rolling characteristics of the shield structure.
Although the figures depict a tubeless mountain bike tire other applications comprise motor vehicles and vehicles of greater weight in general.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20160191 | Jul 2016 | FI | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/FI2017/050560 | 7/28/2017 | WO | 00 |
