Patent Application
20100108217
Not Applicable
Not Applicable
Not Applicable
This invention pertains to inner tubes for common tire systems more specifically, to an improved inner tube and valve system for bicycle tires allowing a user to inflate a secondary tube without removing the tire from the rim or the rim from the bicycle.
As it is commonly known, a bicycle wheel is comprised of 3 elements: a rim, an inner tube (generally, tubes) and a tire. The rim gives rigid support to the bicycle using a hub-and-spoke system and is responsible for the locomotion of the bicycle and its user. The tube provides cushioning between the rim and the ground and absorbs shock by virtue of an annular bladder filled with air at some pressure. To meet this function, inner tubes are generally made from rubber because it is a strong, incompressible material capable of considerable deformation and elastic recovery. These structural properties also provide consistent performance and high reliability of the tube. Also, common inner tubes are manufactured in varying sizes so as to be compatible with different sizes and types of bicycle wheels. The tire protects the tube from puncture and thus helps to maintain the integrity of the wheel. While no one component is more important than the others, the inner tube is frequently the sole cause of bicycle wheel malfunctions.
One of the most common malfunctions in cycling is the occurrence of flat tires. A flat tire is the result of a structurally compromised inner tube causing the tube to lose air pressure. The rim subsequently rides down onto the tire making the wheel unstable. Locomotion and directional control become substantially more difficult and the ride is not as smooth as with a fully pressurized inner tube. The rider must stop riding to avoid damaging the rim and must repair the tube before continuing to efficiently use the bicycle.
Flat tires have many causes, the two most common of which are “pinch-flats” and punctures. A pinch-flat is the result of the tube being pinched between the rim and the tire, usually as the wheel impacts an external object (i.e. a pothole or a tree root). Punctures are more common and occur when a sharp object such as a nail punctures both the tire and the tube. Both generally occur while the user is riding the bicycle and result in the complete loss of air pressure from the tube.
After a flat tire has occurred the rider has limited options for repairing the wheel. In all cases, the wheel must be removed from the bicycle and the tire removed from the rim. After exposing the tube, the rider can either repair the hole using a patch or completely replace the damaged inner tube. Patching the tube requires considerable time to locate the hole and allow the patching adhesive to set. In both circumstances the rider must carry special equipment and tools which add unnecessary weight and bulk. Furthermore, should the user be involved in a race, they would be required to stop cycling, remove the wheel and repair the tube before continuing, resulting in lost time.
The problems associated with flat tires have long been recognized and many solutions have been focused on preventing them from occurring. U.S. Pat. Nos. 6,877,537 (2005) and 5,785,779 (1998) were for tire liners that attempted to isolate the inner tube and decrease the likelihood of puncture. Unfortunately, sharp objects could still puncture that lining and deflate the tube. Even with these systems, pinch flats are still likely to occur as the inner tube is not protected from being pinched inside the tire. U.S. Pat. No. 5,679,184 (1997) proposed a tire design to eliminate pinch flats, but left the tire susceptible to punctures. While these solutions might decrease the incidence of flat tires, they do not completely prevent them and each still requires a traditional inner tube repair.
Solutions to repairing flat tires without replacing or patching the tube have been proposed and usually relate to a “tube within a tube” system. For example, U.S. Pat. Nos. 5,385,191 (1995), 6,820,667 (2004), 5,538,061 (1996), and 2,169,041 (1936) are all some variant of a “tube within a tube”. This concept consists of a primary tube and a secondary tube positioned concentrically in the tire. The primary tube is inflated and functions as a typical inner tube. The secondary tube is positioned within the primary tube and may or may not be attached to the primary tube. Should the primary tube become compromised and run flat, the user can inflate the secondary tube. The secondary tube expands into the space previously occupied by the primary tube and restores the wheel's integrity. The problem with these systems is that in the event of a puncture, the sharp object that punctured the tire and primary tube can also puncture the secondary tube. The secondary tube is also susceptible to pinch flats by getting caught between the tire and the rim along with the primary tube. In these cases, inflation of the secondary tube would fail and the user would have to revert to a traditional repair method.
Similar solutions attempt to alleviate the above problems by positioning multiple inner tubes one atop another within the tire. U.S. Pat. Nos. 5,746,850 (1998) and 4,293,017 (1981) are examples of this arrangement. This configuration does provide more reliability in terms of separate inner tube systems but introduces new problems of complexity in manufacturing, installation and operation. Further disadvantages are present in the valve arrangements of the previous inventions. Most valve arrangements are often complex to operate and involve different size valve stems. Some systems further have separate valves for each tube, requiring a second aperture in the rim. This is undesirable because bicycle rims are usually quite expensive and the user is unwilling or unable to modify them.
State of the art solutions to the issue have not yet addressed the potential for a dual-chambered inner tube and valve system that can address the problems outlined above. It is in this light that the present invention was developed.
Several objects and advantages of my invention are:
The present invention overcomes the inadequacy of the prior art in the field of fixing flat tires. More specifically, a dual-chambered inner tube and valve system is disclosed for use within a standard bicycle wheel. When installed, the invention allows the user to inflate a secondary inner-tube without modifying the components of the wheel and without removing the tire.
The invention consists of two air-tight annular chambers positioned side-by-side and joined together by a common valve stem. The valve stem has two sections, an upper and a lower section. The upper section consists of a standard pneumatic valve (Schrader or Presta style valves, for example) which allows the user to supply air at a given pressure and closes automatically to contain that pressure within the selected chamber. The lower section consists of a selector valve which allows the user to select which compartment is inflated. The valve stem is of standard dimensions so that the aperture of the rim need not be adapted. The dual-chambered inner tube will fit entirely within the annular space formed between the tire and rim and will therefore be completely compatible with a standard bicycle wheel.
Upon installation, both chambers will freely occupy the annular cavity formed between the tire and rim. As the primary tube is inflated, the second tube remains devoid of air and collapses neatly beside the primary tube, within the wheel. Should the primary tube become compromised and air pressure lost, the user may then turn the selector valve in the lower valve stem to a secondary position. This, in effect, closes off the primary tube and opens the secondary tube to the valve stem. The user may then attach an inflation device and begin supplying air to the invention. The second chamber will begin to inflate, expanding into the wheel space and pushing the now deflated primary tube aside. The secondary tube then provides the function of cushion and support in place of the primary tube. The user may now continue riding the bicycle on the fully inflated secondary tube, having never removed the wheel from the bicycle or the tire from the wheel.
Other features and advantages of the present invention will become apparent from the following more detailed description, taken in conjunction with the accompanying drawings, which illustrate the principles of the invention.
In order for those skilled in the art to further understand the present invention, a description is provided in the following details. However, these descriptions and included drawings are intended only to aid in understanding the objects, features and characteristics of the present invention; not to confine the scope or spirit as defined in the claims of the present invention.
A perspective view of the valve system of the present invention is shown in
A perspective view of a section taken along line 4-4 of
