A TYRE WALL PROTECTOR
Field of the Invention
The present invention provides an interior protector that may be used inside a pneumatic tyre to protect against punctures and other damage.
Tyres are typically provided on wheels so as to provide a resiliently deformable surface upon which the wheel is rolled. Many tyres are pneumatic wherein a pocket of air is contained between the tyre and a wheel upon which it is mounted so as to provide a lightweight wheel that can deform and thereby absorb some of the forces created in use. A drawback of using pneumatic tyres is that there is a risk of puncture and therefore deflation of a tyre, which may render a vehicle unusable. Pneumatic tyres have been developed in an attempt to overcome this problem for example by increasing the thickness of the tyre and/or by using different materials. However, tyres are generally required to be fitted onto standard wheels that have pre-defined sizes and shapes and in order to ensure that a tyre can be readily fitted onto a standard wheel the variations that can be made to tyre design without adversely affecting the fitting of the tyre and/or the performance of the wheel are limited. Furthermore, such specialist tyres are often costly and may not be compatible with existing fixtures and therefore may not be desirable. In order to avoid punctures solid tyres may be used as an alternative to pneumatic tyres. However, solid tyres are not generally preferred as they are heavier, provide a less cushioned ride, and can lead to reduced performance and efficiency of a wheel.
Tyre protectors have been proposed as a solution to the problem of pneumatic tyres susceptibility to punctures. A large number of patents and patent applications have been filed for such protectors:
GB 2240953 A discloses a tyre protector formed of interlocking "stair-like" protecting members formed of an engineering plastic and having a lining that can be formed of Kevlar®.
DE 202007013465 Ul discloses a tyre protector that is explicitly not formed of Kevlar® as this material is deemed to be too expensive
US 8240349 B2 discloses a tyre protector including an elastic sealing membrane formed of butyl rubber attached to a perforation -resistant reinforcement made of Kevlar® having a layer of small lubricated glass or ceramic balls enclosed between the Kevlar® layer and the layer of butyl rubber. These balls allow the tyre protector to deform more easily than if it were directly adhered to the inner surface of a tyre.
US 7938158 B2 discloses a tyre protector that is formed of a number of layers including a layer containing laterally extending steel rods. The steel rods have a diameter between 1/16 and ¼ of an inch and are between 7 and 8 inches long.
US 6877537 Bl discloses a tyre protector formed of a strip of recycled aluminium.
US 5785779 Al discloses a tyre protector formed of Kevlar® fibres wrapped in a flexible plastic strip.
GB 526328 A discloses a tyre protector formed of steel ribbon enveloped in a covering of canvas, rubber sheeting or similar. The steel ribbon has a significant width.
GB 323394 A is a document from 1930 and discloses a tyre protector with a very complex construction consisting of layers of many different materials such as raw dense linen, wide mesh elastic fabric vulcanised with rubber, and layers of narrow meshed cotton with rubber threads woven through.
US 1362516 Al is a document from 1920 and discloses a tyre protector comprising an inner layer of rubber or rubber canvas, a pad of unwoven cotton fibre that is stitched in position, an outer strip of tough muslin, and outer layer of rubber or rubber canvas. Despite these disclosures, the use of tyre protectors is still not widespread. In particular, none of the above tyre protectors have been commercially successful. Therefore, there is a need for an improved tyre protector that is relatively cheap, has a simple construction, and that provides good protection against punctures. Summary of the Invention
The present invention provides an interior protector for a tyre wall comprising a core and at least one outer, wherein:
said core is secured in use to the tyre wall by said outer;
the at least one outer is formed from butyl rubber;
the core comprises at least one layer of fibrous Kevlar® and a wire-reinforcing layer, the wire-reinforcing comprising circumferentially extending wires cut at intervals along a length of the protector.
The present invention is advantageous in that it provides a strong and resilient protector that provides good protection against punctures but that also has a simple and relatively cheap construction. The wire-reinforcing layer provides additional strength and puncture resistance whilst the cuts in the wires maintain the flexibility of the protector and allows it to be easily located within a tyre. In use, the protector of the present invention and the core thereof are secured to a tyre wall by means of the outer of the protector. That is, it is the outer of the protector (rather than any other part) that is secured to the tyre. The outer may secure the protector to the tyre in any means apparent to the person skilled in the art. The outer may be secured by means of an adhesive. Alternatively or additionally the outer may be sized and shaped such that when fitted within a tyre it is resiliently held in position within the tyre. Alternatively or additionally, a brace may be used to secure the protector in position within a tyre, as described below.
The present invention may be provided independently from a tyre and a user may then locate the protector within a tyre before use. Alternatively, the present invention may be provided to an end user when already located within a tyre.
The protector of the present invention may be a continuous annular loop (in the same manner as a tyre) that is dimensioned to fit snugly against an inner wall of a tyre when in use. Alternatively, a protector according to the present invention may be provided as a length that is of an appropriate length to be laid within a tyre or that can be cut to such an appropriate length. If a protector is provided as a length, rather than an annular loop, distal ends of the length may comprise interlocking features and or adhesive that allow such a protector to be firmly secured within a tyre as an annular loop.
The core of the protector comprises at least one layer of fibrous Kevlar®. The Kevlar® may be inlaid into butyl rubber so as to be static in use. The fibrous Kevlar® may be formed in any manner apparent to the person skilled in the art. In preferred embodiments of the invention the layer of fibrous Kevlar® has substantially the same lateral width as the wire-reinforcing layer. However, it is to be understood that the layer of fibrous Kevlar® may be narrower or wider than the wire-reinforcing layer if it is deemed advantageous or desirable for any specific embodiment of a protector according to the present invention.
Preferably the layer of fibrous Kevlar® will have the same width as, or be wider than, a surface contacting portion of a tyre in which it is mounted. The surface contacting portion of a tyre being that portion of the outer surface that might reasonably come into contact with the ground during use of the tyre. This width of the layer of fibrous Kevlar® is preferred as it is most likely that punctures will occur by objects piercing the surface contacting portion of a tyre and, as a result, it is generally this portion of a tyre that requires the most protection. In some embodiments it may be further preferred that the layer of fibrous Kevlar® extends to protect all or part of sidewalls of a tyre.
The core of the protector further comprises at least one wire-reinforcing layer to provide improved puncture resistant properties. The wire-reinforcing layer is provided as a plurality of circumferentially extending wires. The wire of the wire-reinforcing layer is preferably formed from a strong, durable metal, such as steel.
The wire of the wire-reinforcing layer is not continuous around or along a protector according to the present invention. Rather, the wire is cut at intervals along a length of a protector i.e. at circumferential intervals when the protector is in use within a tyre. The cutting of the wire allows for expansion and flexure, for example to enable stretch and further flexibility of the protector and any tyre within which it may be located. This can facilitate fitting of the protector and of a tyre and can allow for expansion in use, for example due to temperature changes.
Individual wires within the wire-reinforcing layer extend circumferentially around a protector, when the protector is in use, and are cut at intervals around that circumference. Each wire may be cut at the same circumferential points as each other wire. Alternatively, it may be preferred that wires differ in the circumferential points at which they are cut. For example, the cut points of each of the wires of the wire- reinforcing layer may be randomly circumferentially distributed such that they do not align with the cut points of immediately adjacent wires, so as not to form any circumferential weak points.
In some embodiments of the present invention the wire-reinforcing layer provides an inner layer around which the Kevlar® is arranged as an outer layer, said outer layer being surrounded in turn by a butyl rubber layer.
In the same manner as the layer of fibrous Kevlar® it is preferable that the wire- reinforcing layer will have the same width as, or be wider than, a surface contacting portion of a tyre in which it is mounted. This width of the wire-reinforcing layer is preferred as it is most likely that punctures will occur by objects piercing the surface contacting portion of a tyre and, as a result, it is generally this portion of a tyre that
requires the most protection. In some embodiments it may be further preferred that the wire-reinforcing layer extends to protect all or part of sidewalls of a tyre.
The protector of the present invention is suitable for use with substantially any pneumatic tyre, including, but not limited to, car tyres, lorry tyres, motorcycle tyres, bicycle tyres, and other vehicle tyres. Embodiments of the present invention may be adapted to be particularly suitable for use with a specific tyre. In particular, an embodiment of a protector according to the present may be sized and shaped to be preferably used with a specific size and type of tyre. A preferred embodiment of the present invention is particularly suitable for use with motorcycle tyres.
A tyre protector according to the present invention may comprise only a single layer of fibrous Kevlar®. Alternatively, a tyre protector according to the present invention may comprise a plurality of layers of fibrous Kevlar®. Each layer may have any or all of the features of a layer of fibrous Kevlar® described above.
The core of a protector according to the present invention may be formed inwards of the outer. That is, a protector according to the present invention may have two distinct and visible layers, an inner core and an outer. Alternatively, it may be preferred that a protector according to the present invention is formed such that the core is completely contained within and surrounded by the outer. This may be preferred to ensure that the core is securely held in place and properly located when a protector is in use. It may also prevent the core detaching from the outer. A protector according to the present invention may comprise either a single wire- reinforcing layer or a plurality of wire-reinforcing layers. If a protector comprises a plurality of wire-reinforcing layers they may all be adjacent to one another, alternatively they may be separated by one or more layers of fibrous Kevlar®. The wires of the wire-reinforcing layer may be formed of any suitable material. The skilled person will be able to readily determine a suitable material for the wires. In preferred embodiments of the invention the wires will be formed of metal.
In some embodiments of the present invention the or each wire-reinforcing layer provides an inner layer around which the at least one layer of fibrous Kevlar® is arranged, such that the at least one layer of fibrous Kevlar® provides the first barrier to an object puncturing the protector and reaching the interior of the tyre, with the or each wire-reinforcing layer acting to reinforce the layer of fibrous Kevlar® and improve the puncture resistance of the protector.
The protector of the present invention may have any shape and size that allows it to be easily and securely mounted within a tyre. For some tyres, such as car and lorry tyres, it may be preferred that a protector is formed to have a substantially rectangular cross- section. For other tyres different cross-sectional shapes may be preferred. For example, for a motorcycle or bicycle tyre it be preferable that the protector is approximately crescent-shaped in cross-section.
The present invention also provides brace for securing a protector according to the present invention within a tyre. When in use within a tyre, a brace according to the present invention will be positioned inwards from the protector. A brace will be sized to snugly and securely fit within a tyre with a protector according to the present invention positioned between the brace and an inner wall of the tyre. Preferably a brace will be sized such that it can be pressed into position by user, either manually, or by using conventional tooling, such as a hammer. In particular, a brace will be formed with a shape that it may closely conform to an inner side of a protector and the side walls of a tyre in which that protector is intended to be mounted.
Preferably a brace according to the present invention will be formed of a length with distal ends. The length being equivalent to the inner circumference of a cooperating protector when mounted within a tyre. The distal ends of a brace may comprise interlocking features, to allow the brace to be formed into an annular member when it is mounted within a tyre by interlocking the interlocking features of the distal ends.
A brace according to the present invention may be formed of any suitable material. As will be readily appreciated, a brace according to the present invention will preferably be formed of resilient material such that it may be securely held in position within a tyre simply by pressing it into position and without need for any further fixing means other than air pressure within a pneumatic tyre or possibly an inner tube positioned within a pneumatic tyre.
In preferred embodiments of the invention a brace may be formed of a resilient plastic material such as HDPE. A brace may be formed of a single material or may additionally comprise further materials. For example, a brace formed of a resilient plastic material may further comprise a wire mesh embedded therein or otherwise attached thereto to provide added resilience and strength to the brace.
The brace may be formed with any size and shape that will allow to be securely held in position within a tyre and to thereby hold a protector according to the present position within in a tyre. Advantageously, the brace may have a cross-sectional profile that matches the profile of a protector with which it is intended to be used such that the two components can fit snugly together within a tyre. For example, the thickness of a brace may vary across its width from a relatively thin central portion to relatively thicker outer portions to provide a concave cross-sectional shape to match a protector with a convex cross-sectional shape.
When a brace according to the present invention is used with a protector and a tyre, the user will first position the protector in an appropriate position within the tyre. The user will then position the brace adjacent its final position within the tyre, inwards from the protector. The user will then press the brace securely into position within the tyre so as to hold the protector in position. This can be done either by a user simply pressing the brace manually with their hands and/or feet by using a suitable tool, such as a hammer. The present invention further provides a system for puncture proofing a tyre comprising a protector and a brace. The system comprises a protector according to the present invention, as described above, and a cooperatively shaped and sized brace according to
the present invention, as described above. The system may additionally comprise a tyre in which the protector and brace can be mounted. The three components can be provided already assembled together in the form a puncture resistant tyre. The tyre of the system may be a conventional commercially available tyre or may be a tyre specifically designed and intended for use with the protector and brace.
The present invention further provides a method of puncture-proofing a tyre. The method comprising the step of mounting a protector according to the present invention within a tyre in any manner described above. The method may further comprise the step of securing the protector in position within a tyre using a brace.
Further features and advantages of the present invention will be apparent from the specific embodiments that are illustrated in the drawings and that are shown below. Drawings
Figure 1 is an isometric view of a first embodiment of a protector according to the present invention;
Figure 2 is a front view of the protector of Figure 1;
Figure 3 is an isometric cross-section of the protector of Figures 1 and 2 when in use; Figure 4 is an isometric cross-section of the protector of Figures 1 to 3;
Figure 5 is an exploded view of the protector of the previous Figures;
Figure 6 is a cross-section of a second embodiment of a protector according to the present invention when in use. A first embodiment of a protector 1 according to the present invention is shown in Figures 1 to 5. The protector 1 is a substantially annular body comprising a butyl rubber outer 2 and a core 3. As shown in Figure 3, the protector 1 is shaped such that, when in use, it snugly fits within an inner annular wall of a tyre 10. In particular, an outer side of the protector 1 lies against, and is contact with, the complete width of an inner annular wall of the tyre 10.
The core 3 of the protector 1 comprises an annular Kevlar® layer 5 and an annular wire- reinforcing layer 4. The wire-reinforcing layer 4 is positioned inwards (in relation to its use) from the Kevlar® layer 5. As best shown in Figure 5, the wire-reinforcing layer 4 is cut at circumferential intervals to provide flexibility to the protector 1. The core 3 is entirely encased within the outer 2. The core 3 is of a width such that it extends entirely across a road-contacting portion of the tyre 10 when positioned within the tyre but does not extend around side-walls of the tyre.
The operation of the first embodiment of the invention will be readily appreciated from the Figures. The Kevlar® layer 5 and the wire-reinforcing layer 4 provide reinforcement against punctures. In particular if the tyre 10 runs over an object that pierces the road-contacting portion of the tyre 10 it will impact the protector 1. The outer 2 of the tyre will provide some protection against puncture but only to the same extent as if the tyre 10 had been provided with a road-contacting portion of a thickness equivalent to the combined thickness of the tyre 10 and of the outer 2 of the protector. This is because the outer 2 is formed of butyl rubber, as are most commercially available tyres. It is the core 3 of the protector that provides substantial protection against punctures. Unless an object passes completely through the road-contacting portion of the tyre 10, the outer 2 of the protector, and the core 3 of the protector it should not cause a puncture.
The core 3 provides two layers that may prevent an object puncturing the tyre 10 and thereby make the tyre more puncture-resistant. An object puncturing the tyre 10 and the outer 2 will first contact the layer of fibrous Kevlar® 5, which is reinforced by the wire- reinforcing layer 4. It is unlikely that the object will be able to pass through the layer of fibrous Kevlar® 5, particularly due to the reinforcing action of the wire-reinforcing layer 4. Importantly, the presence of the wire-reinforcing 4 layer directly inwards from the layer of fibrous Kevlar® 5 will prevent localised inward deformation of the layer of fibrous Kevlar® 5, significantly improving that layer's puncture resistance.
Even if an object does pass through the layer of fibrous Kevlar® 5 it will then impact the wire-reinforcing layer 4, which will then provide further direct resistance against
the object. In this manner, it is extremely unlikely that an object would pass through the protector 1 and puncture the tyre 10.
Although, in the embodiment shown in the Figures 1 to 5 the protector 1 only covers the road-contacting portion of the tyre 10 and not the sidewalls, it will be readily appreciated that a protector 1 according to the present invention could be modified in a straightforward manner such that it extends to protect the sidewalls of a tyre 10. This may be particularly preferred in tyres 10 with more curved profiles, such as motorcycle and bicycle tyres, wherein there is no clear distinction between a road-contacting portion of a tyre 10 and its side walls. The protector of Figure 6 is formed in this manner.
A second embodiment of a protector according to the present invention is shown in Figure 6. This embodiment is intended for use with a motorcycle tyre and is shown in position in such a tyre 10. The protector has a curved shape to fit the inner profile of the tyre 10 and extends partially around side walls of the tyre 10. The protector is formed in the same manner as the protector 1 of Figures 1 to 5 in that it comprises a core 3 formed of a layer of fibrous Kevlar® and a wire-reinforcing layer and an outer 2 formed of butyl rubber. The protector operates in the same manner as the protector 1 of Figures 1 to 5.
The protector of Figure 6 is held in position using a brace 6. The brace 6 is a length of resilient FIDPE that is shaped such that it can be snapped into position within the tyre 10 to hold the protector in position. In order to position the protector within the tyre it is first inserted into position and a user will then press the brace 6 into position within the tyre until it snaps into position and can not be removed without difficulty. The brace 6 does provide some additional puncture resistance but its primary purpose is to securely hold the protector in position.