Abstract:
A compact, easy to use tire tread gauge has a window that displays an indication of the condition of an automobile tire and whether it needs to be replaced because of tread wear.

Description:
TECHNICAL FIELD 
       [0001]    This invention relates broadly to an apparatus for measuring the depth of tire treads for grooved tires. More particularly, this invention relates to a compact and attractive tire tread gauge that is a convenient, easy to use tool, used to measure tire treads to maintain safety. The gauge may be used to measure tire tread depth in standard and/or metric units. 
       BACKGROUND 
       [0002]    The tread of a tire is the portion of the circumferential surface of the tire that contacts the road surface. Traditionally, automobile, motorcycle, truck, bicycle, and airplane tires have a series of grooves that intersect the tire tread dividing it into several parts. On most race cars, “slick” tires are used. These tires have a single tread that extends from one sidewall to the other and has no grooves. Standard tires (i.e. tires with grooves) have a strong grip of the road surface so long as (i) the tire is not over-worn and (ii) the weather is dry and warm. In wet weather conditions they tend to aquaplane or hydroplane because water on the surface of the road interferes with the tread contacting the road surface. In Formula 1 racing, special grooved tires are fitted on the race cars during wet conditions. The pattern of grooves serves to disperse water and somewhat avoid aquaplaning and hydroplaning. There are two types of Formula 1 wet weather tires: “wet” and “extreme wet”. The former are used when it is raining and the latter when there are puddles of standing water on the track. 
         [0003]    Other tires (e.g., those used on passenger vehicles and on commercial trucks, airplanes, etc.) have multiple treads that are separated by complex grooves. The grooves do not improve traction under dry conditions, but they do serve to avoid hydroplaning and aquaplaning in wet weather. The grooves also provide an easy means for measuring the age of the tire and whether the tire is safe to drive on. As tire treads wear, the depth of the grooves is shortened thereby diminishing the ability of the grooves to effectively disperse water. 
         [0004]    Most drivers examine their vehicle&#39;s tires just by looking at the treads. However, there are more accurate ways to measure the depth of the grooves, the age of the tire, and whether the tire is safe. A new tire typically has 10/32″ groove depth. A groove depth of 8/32″ is still fine to drive. A depth of 6/32″ is an ample depth, but it may be difficult to stop in the snow. With a depth of 4/32″, it may be difficult to stop in the rain. A tire is considered “bald” when the groove depth is 2/32″. This tire is not safe to use even in dry conditions. 
         [0005]    One way to measure the groove depth is to use a coin. Place a penny into several tread grooves at least 15″ apart circumferentially on the tire. When part of Lincoln&#39;s head is covered, it means the tire has more than 2/32″ of tread thickness. If the top of his memorial is always covered, then the tire has more than 6/32″ of tread thickness. However, it is difficult for most people to remember these rules. 
         [0006]    There are plenty of tire tread gauges available, but they are relatively large and difficult to use. 
       SUMMARY 
       [0007]    The present invention provides a compact, attractive, and easy to use tire tread gauge. According to a first embodiment, the gauge is a cylinder that is approximately one and one eighth inches in diameter and approximately one quarter of an inch thick. There is a radial bore at the bottom of the cylinder through which a measuring stick extends. At the top of the stick is a stopper that prevents the stick from completely exiting the cylinder. The stopper is coupled to indicting text messages that are viewable through a window on one side of the cylinder. When the stick is fully within the cylinder, the text message is preferably a brand name or the name of a company that is being promoted by gifting the gauge to their customers. When the stick extends fully out of the cylinder ( 10/32″ or 7.9375 mm), the text message is “NEW” in white lettering, preferably on a green background. When it extends out 8/32″ or 6.35 mm, the message displayed is “GOOD” in white lettering, preferably on a blue background. When it extends out 6/32″ or 4.7625 mm, the message is “OK” in white lettering, preferably on a purple background. When the stick extends out 4/32″ or 3.175 mm, the message is “REPLACE” in white lettering, preferably on an orange background. When the stick extends only 2/32″ or 1.5875 mm, the message is “DANGER” in white lettering, preferably on a red background. 
         [0008]    According to second, third, and fourth embodiments, the portion of the cylinder where the measuring stick exits is flattened. This may help making sure that the stick lies along a radius of the tire so that more accurate measurements are made. Otherwise, these embodiments function in the same way as the first embodiment. The second, third, and fourth embodiments are also decorative. One is designed to look like a flat tire. One is designed to look like a donut, and one is designed to look like a woman&#39;s purse and may assume a shape other than cylindrical. In all four embodiments, a loop may be provided opposite the stick exit for attaching the gauge to a key ring. These are examples of designs that can be used for the invention. 
         [0009]    It is also contemplated that as part of the present invention that the displaying of tire condition may be part of a video display unit. Further, it is also an object of the invention to have an audible alert to inform the user as to the condition of a tire. Additional objects and advantages of the invention will become apparent to those skilled in the art upon reference to the detailed description taken in conjunction with the provided figures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a transparent view through one side of the first embodiment showing the measuring stick fully retracted; 
           [0011]      FIG. 2  is a view similar to  FIG. 1  showing the measuring stick fully extended by an optional spring; 
           [0012]      FIG. 3  shows the message window with the measuring stick fully retracted; 
           [0013]      FIG. 4  shows the message window with the measuring stick fully extended; 
           [0014]      FIGS. 5-8  show the message window with the measuring stick in various stages of retraction; 
           [0015]      FIGS. 9-10  show opposite sides of a second embodiment with the measuring stick fully retracted; 
           [0016]      FIGS. 11-12  show opposite sides of a third embodiment with the measuring stick mostly retracted; and 
           [0017]      FIGS. 13-14  show opposite sides of a fourth embodiment with the measuring stick partially retracted. 
       
    
    
     DETAILED DESCRIPTION 
       [0018]    Turning now to  FIGS. 1 through 8 , a first embodiment  10  of the gauge is a cylinder  12  that is approximately one and one eighth inches in diameter and approximately one eighth inch thick. There is a radial bore  14  at the bottom of the cylinder through which a measuring stick  16  extends through a wall that is approximately one quarter inch thick. At the top of the stick is a stopper  18  that prevents the stick from completely exiting the cylinder  12 . The stopper is coupled to a plurality of indicting text (or color) messages  20  that are viewable through a window  22  on one side of the cylinder  12 . 
         [0019]    As shown in  FIG. 2 , it may be advantageous to provide a biasing spring  17  to urge the stick  16  out of the housing  12 . However, it may be deemed sufficient to allow gravity to perform this function without the aid of a spring. 
         [0020]    When the stick  16  is fully within the cylinder as shown in  FIGS. 1 and 3 , the text message  20  is preferably a brand name or the name of a company that is being promoted by gifting the gauge to their customers. 
         [0021]    When the stick  16  extends fully out of the cylinder ( 10/32″ or 7.9375 mm) as shown in  FIG. 4 , the text message  20  is “NEW”, preferably on a green background or simply the color green with no text message. 
         [0022]    When the stick  16  extends out 8/32″ or 6.35 mm as shown in  FIG. 5 , the message displayed is “GOOD”, preferably on a blue background or simply the color blue with no text message. 
         [0023]    When the stick  16  extends out 6/32″ or 4.7625 mm as shown in  FIG. 6 , the message  20  is “OK”, preferably on a purple background or simply the color purple with no text. 
         [0024]    When the stick  16  extends out 4/32″ or 3.175 mm, the message  20  is “REPLACE”, preferably on an orange background or simply the color orange with no text. 
         [0025]    When the stick  16  extends only 2/32″ or 1.5875 mm, the message  20  is “DANGER”, preferably on a red background or simply the color red with no text. 
         [0026]    According to second, third, and fourth embodiments,  FIGS. 9-14 , the portion of the cylinder where the measuring stick exits is flattened. This may help making sure that the stick lies along a radius of the tire so that more accurate measurements are made. Otherwise, these embodiments function in the same way as the first embodiment. The second, third, and fourth embodiments are also decorative. One  110  is designed to look like a flat tire. One  210  is designed to look like a donut, and one  310  is designed to look like a woman&#39;s purse and may assume a shape other than cylindrical. All are provided with a window  122 ,  222 ,  322  which operates as described with reference to the first embodiment. 
         [0027]    In all four embodiments, a key loop  30 ,  130 ,  230 ,  330  may be provided opposite the stick exit for attaching the gauge to a key ring. 
         [0028]    There have been described and illustrated herein several embodiments of a tire tread gauge. While particular embodiments of the invention have been described, it is not intended that the invention be limited thereto, as it is intended that the invention be as broad in scope as the art will allow and that the specification be read likewise. It will therefore be appreciated by those skilled in the art that yet other modifications could be made to the provided invention without deviating from its spirit and scope as claimed.