Patent Application
20170008343
The invention relates to a tire, in particular to, but not restricted to, a bicycle tire, equipped to be mounted around a wheel rim.
Bicycle tires usually are pneumatic tires, having a hollow inflatable inner tube and an outer casing that can be mounted around the front and the rear wheel of the bicycle. It is generally known that pneumatic tires can run flat, which is inconvenient for the bicycle user. It is true that the driving and suspension characteristics of a pneumatic tire are outstanding.
Among other things in view of the environment, the use of bicycles, in particular in big cities, is increasingly propagandized. In that context companies arise having large numbers of bicycles for rent. It is clear that having to repair the tires of these rental bikes regularly is annoying for the rental company's business.
It has been tried to solve this problem by providing non-pneumatic tires. From CH46515A a massive, i.e. a non-pneumatic, tire is known, built from juxtaposed massive elements, tied together with massive rods extending in a channel close to the inner circumference of the tire.
This known tire, however, has the disadvantage that it fits only to the rim of one specific wheel. Aim of the invention is to provide a tire that will fit to wheel rims in a broad range of sizes and widths.
The invention now provides a tire, comprising an annular massive tire body having an essentially round or oval cross section having a centre MB, and having an outer circumference CO forming a tread and an inner circumference CI facing the centre of the annular body, the body containing a longitudinal pull cable channel having a cross section having a centre MK, the channel containing a pull cable, and wherein the distance between centre MK and the inner circumference CI is between 7 and 18 mm measured along a line connecting MK and MB.
The tire according to the invention is massive, i.e. the tire is a non-pneumatic tire and the tire body consists of an elastic and resilient material in order to provide good suspension and driving characteristics. Suitable resilient and flexible materials are for example rubber and polymeric elastomers. Preferably the material is a closed-cell foam made of the resilient material.
The tread may be provided with a profile to enhance the driving characteristics, in particular preventing the bike it is mounted on from slipping. Suitable tire profiles for various types of bicycles are known per se in the art.
The tire body has an essentially round or oval cross section. Depending on the type of bicycle the cross section may locally deviate from a true round or oval shape, e.g. the tread formed by the outer circumference for a racing bicycle will be narrower than for a touring bicycle.
The body contains a longitudinal pull cable channel. The channel is equipped for leading through a pull cable intended for tightening the tire body to the rim of a wheel on mounting. The position of the pull cable channel within the tire body is chosen such that the distance between centre MK and the inner circumference CI is between 7 and 20 mm measured along a line connecting MK and MB. Preferably the distance between centre MK and the inner circumference CI is between 8 and 16 mm.
The pull cable channel does not only serve to guide the pull cable, but it may also affect properties of the tire such as driving and suspension characteristics. The volume of the tire channel may be larger than the minimal volume required to contain the guide cable. Usually, the volume of the channel is at most 25 vol. % of the total volume of the tire. Preferably, it is between 1 and 15 vol. %.
The invention thus provides a tire, equipped for being mounted around a wheel rim having a rim bottom outer diameter DVb and rim edges having a rim edge outer diameter DVr.
The tire comprises an annular tire body which, apart from the annular cable channel, is substantially massive, so filled with the resilient and elastic material. The cable channel is equipped for leading through the pull cable intended for tightening the tire body to the rim on mounting. Preferably, the inner diameter DB of the inner circumference CI of the tire is at most 5% larger than the rim bottom outer diameter DVb but preferably it is at least equal to and more preferably it is up to 3% smaller than DVb of the rim the tire will be mounted on. When having been mounted on the rim the tire will have been drawn into the rim until it meets the rim bottom or a annular hollow cavity may remain between the rim and the rim bottom. This cavity may extend up to 15, preferably up to 10 mm above the rim bottom.
To obtain a firm connection of the tire to a rim, in tensioned position the position of MK will range from 10 mm above the rim bottom to 5 mm above the rim edge.
In cross sectional view, the distance between MK and the inner circumference CI is between 7 and 20 mm, preferably between 8 and 18 mm, measured along a line connecting MK and MB. Suitable positions of the pull cable channel are determined by the resilience and elasticity of the tire body. The more resilient and elastic the material of the tire body, the higher the percentage defined in the preceding paragraph can be chosen.
When mounting the tire, it is positioned on the rim edges (“shoulders”) of the rim. The elasticity of the tire body allows to do so even although the diameter of the inner circumference may be smaller than the rim outer diameter. With the aid of a tensioning system (e.g. as known per se from GB181473 and DE336054) the elastic material of the tire body is drawn into the rim, i.e. between the rim edges, by the (internal) pull cable. Since the tire body is of elastic material, the tire can deform in conformity to a large variety of rim shapes and rim widths. For example, the different rims on which a tire of the invention can suitably mounted may have widths ranging a factor of two. For example, one type of tire is fit rims having a width in the range 16-32 mm
Thus, according to the invention, use can be made of one universal tire, i.e. one tire size for various rim widths and shapes, which is also advantageous for the large rental companies' businesses.
Depending on the depth of the rim in relation to the position of the pull tire channel and the elasticity of the tire material, after tensioning the pull cable, a hollow cavity may remain between the inner circumference CI of the tire and the rim bottom. This cavity may enhance the suspension and driving characteristics of the tire. In particular, it can absorb shocks due to a collision with a sharp edge of an object (e.g. a curb), because the tire then is pressed into the cavity.
The pull cable is tensioned to the extent that the pull cable is in a position below the edges of the rim or at most 5 mm above the edges. With tensioned pull cable the tire is securely fixed to the rim and without releasing the pull cable it will be impossible to remove the tire from the rim. Preferably, the pull cable channel has a reinforced wall. For example the reinforced wall comprises a hollow wound metal wire spiral, as used e.g. in Bowden cables. The presence of a metal wire spiral eases the sliding of the cable through the cable channel. Also the application of a lubricant can ease the tensioning of the pull cable.
The pull cable channel is provided with a hole radially extending to an opening in the inner circumference. Through this opening the ends of the tire cable are passed to outside the tire in a radial direction and joined.
Preferably both ends of the tire cable are fed through a hollow threaded end and fastened to the threaded end.
In general a rim contains an opening for mounting the valve of a pneumatic tire. When mounting the tire according to the invention on a rim, the opening in the inner circumference of the tire is aligned with said opening in the rim, and the threaded end, containing the cable ends, is passed through the aligned openings. Preferably the size of the threaded end is smaller than the diameter of the opening in the rim. In practice an M6 threaded end is suitable for the commonly applied rims.
The tire then can be tightened to the rim by pulling the threaded end through the opening in the rim thus tensioning the pull cable.
The tire preferably contains a T-shaped element through which the ends of the pull cable are guided from the cable channel into the protruding leg of the element to outside the tire body. The T-shaped element prevents the mounted tire from sliding over the rim, i.e. it prevents rotation of the tire over the rim in the direction of normal rotation of the tire, for example during acceleration or deceleration. Such sliding will cause irregularities in the tire which makes riding the bike unpleasant.
As an additional effect the presence of a T-shaped element protects the tire from being damaged by the tensioning action of the cable, e.g. from being cut in by the pull cable. Another way to diminish the risk of damaging the tire, in particular the pull cable channel, is the use of a cable of a smooth material or a cable clad with a smooth material, e.g. silicon rubber.
In a preferred embodiment of the tire according to the invention this T-shaped element is incorporated by moulding it in the tire during the manufacturing process of the tire.
The tire is particularly useful for being mounted on a rim to manufacture a wheel. The invention further relates to a tire containing a T-shaped element, the tire having been mounted on a rim containing a valve hole, the ends of the pull cable having been secured to the rim through the valve hole.
In an alternative embodiment the pull cable has the shape of a screw clamp. Such clamp comprises a, usually metal or plastic, band that is tightened by turning a captive screw having a screw thread. Into the band a grooved pattern has been cut or pressed corresponding to the screw thread of the captive screw. By turning the captive screw the band becomes narrower. The band and the captive screw can be positioned in the pull cable channel, which in this embodiment usually will be just large enough to contain the band. The wall of the tire body then is provided with a hole giving access to the captive screw, which allows the tire to be tightened to the rim by turning the captive screw through the hole in the tire body.
Preferably, the hole and the screw are positioned in such a way in the tire body that a screwdriver, Allen key or other key matching the screw head accessing the screw for rotating it, can be positioned obliquely into the side wall, preferably close to perpendicular to the side wall. This allows a convenient tightening of the tire around the rim. Moreover, this positioning of the screw allows easy access of an electric screwdriver to the screw, making the tightening even more convenient and fast.
Applying a screw clamp as the tire cable has the advantage that it is not necessary to fix the tire with respect to the rim since sliding of the tier along the rim will not cause irregularities. In addition to the screw clamp the tire may contain a T-shaped element to fix the position of the tire on the rim. In such case, the T-shaped element is not necessary to guide the pull cable and may therefore also have a massive shape structure that does not have space to allow a cable to be guided through.
The tire according to the invention in practice will be applied, mounted on a wheel rim. The invention thus further relates to a structure comprising a tire as described above, mounted around a wheel rim, having a rim bottom having a rim bottom outer diameter DVb and rim edges having a rim edge outer diameter DVr, which tire comprises an annular tire body which, apart from a narrow annular cable channel, is substantially massive, which cable channel is equipped for leading through a pull cable intended for tightening the tire body around to the rim on mounting, the cross section of the substantially massive tire body, when the pull cable is in non-tightened position, being essentially round or oval and the inner diameter DB of the tire body, when the pull cable is in non-tightened position, being substantially but preferably at most 5% larger than the rim bottom outer diameter DVb.
The invention further relates to a structure comprising a tire as described above, comprising an annular massive tire body, mounted around a wheel rim having a rim bottom having a rim bottom outer diameter DVb and rim edges having a rim edge outer diameter DVr, wherein the annular tire body contains an annular cable channel, which cable channel contains a tensioned pull cable that tightens the tire body around to the rim and wherein the inner diameter DB of the tire body ranges from the rim bottom outer diameter DVb up to 1 to 5 mm larger than the rim bottom outer diameter DVb.
In a preferred embodiment the rim bottom has a valve hole and the ends of the pull cable are secured to the rim through the valve hole.
In a further preferred embodiment the pull cable has been tightened around the rim by the screw clamp as described above. In general the position of the pull cable will range from 10 mm above the rim bottom to 5 mm above the rim edges 3.
The invention will be elucidated by the following exemplary drawings, without being restricted to the shown specific embodiments.
In these drawings:
In
In
In cross sectional view (as in
In
In
When mounting the tire on a rim, protruding leg 13 is aligned with the valve opening in the rim making threaded end 15 accessible from outside the rim. Threading a nut or other element having an internal thread corresponding with external thread 16 of threaded end 15, will tension the pull cable. In order to prevent the nut or other element from entering into the valve opening a washer can be placed between rim and nut. The resulting firm connection of the T-shaped element to the rim further stabilizes the position of the tire on the rim.
In
31 is a block fastened to end 30a of band 30 and contains captive screw 32. Opposite end 30b of band 30 is lead through block 31 in matching position with end 30a. When captive screw 32 is turned around end, 30b is moved with respect to end 30a thus tightening band 30.
In
It is noted:
that there is preferably one tire size for different rim widths, making the proposed configuration very suitable for the consumer aftermarket;
that the proposed tire in particular has been developed as a bicycle tire but can also be used for wheel chairs, prams and wheel barrows etc.;
that the pull cable after having been tensioned is positioned below or at most slightly above the rim edges, so that the tire cannot come off the rim;
that the tire during the tensioning of the pull cable deforms in conformity with the type of rim and/or the rim width and shape.
Thus the invention provides a tire which, since it is massive, cannot run flat, which can be reliably mounted on the rims and which can be used for rims having different shapes and having different rim edge width an height sizes. In particular the tire according to the invention is useful for companies having large numbers of bicycles for rent, where the present invention will have an advantageous effect on the business of such (large) bicycle rental companies, having its impact on the popularity of rental bicycles, in particular in crowded urban areas (for example Chinese big cities) and thus on the growth of their use as replacement of car use.
The tire can also be advantageously used by private bicycle owners when they need to replace a tire. Due to the large range of rim dimensions the tire can be applied they do not have to bother about the specific wheel size of their bicycle. Also mounting and maintenance is easy.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1040643 | Jan 2014 | NL | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/NL2015/050068 | 2/2/2015 | WO | 00 |
