Abstract:
A vehicle Central Tire Inflation Systems (CTIS). Specifically, the invention includes, but is not limited to, a quick-release fitting in fluid communication with the CTIS and attached to an air supply hose which terminates in another threadable or quick-release fitting for attachment to the wheel inflation stem. The device allows pressurized air to be supplied to the tires from the CTIS, but quickly disconnected from a tire in the event of a tire casualty or need to change wheel rims.

Description:
TECHNICAL FIELD 
     This invention relates in general to vehicle tire inflation, and in particular, to a vehicle Central Tire Inflation System (CTIS). Specifically, the invention relates to an improved CTIS for High Mobility Multipurpose Wheeled Vehicles (HUMMVEEs), a military, multi-purpose vehicle, and other vehicles using a CTIS. 
     BACKGROUND OF THE INVENTION 
     Various vehicles have developed a system for automatically inflating vehicle tires while in transit. Typically referred to as a Central Tire Inflation System (CTIS), the CTIS allows the vehicle driver to inflate or deflate the vehicle&#39;s tires to a higher or lower pressure respectively to accommodate a variety of vehicle loads, and road and traffic conditions. Control of the vehicle tire air pressure is provided by an air pressure controller that can be automatically adjusted or manually controlled in the cab by the vehicle&#39;s driver. The system provides an air compressor that is connected through the air pressure controller to the vehicle&#39;s front and rear tires. Rotary seal connections are provided at each wheel to permit flow of air from the air supply to the tires while the vehicle is in motion and the wheels are rotating. 
     There are, however, several drawbacks to some existing CTISs. For example, in the HUMMVEE, the tires cannot be inflated directly at the rim, but only through the existing CTIS via the “tank Valve” at the hub. Additionally, the CTIS cannot be disabled. Also, only “standard,” or military issue rims or wheels can be used to ensure operability with the CITS. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to an improvement in the HUMMVEE CTIS. Specifically, the invention provides a quick-disconnect feature for disconnecting one tire from the CTIS, and thereby preventing the opposite tire from deflating. The claimed invention includes, but is not limited to, a quick-release fitting in fluid communication with the CTIS and attached to an air supply hose which terminates in another threadable or quick-release fitting for attachment to the wheel inflation stem. The device allows pressurized air to be supplied to the tires from the CTIS, but quickly disconnected from a tire in the event of a tire casualty or need to change wheel rims. The claimed invention also permits use of a variety of “civilian”, or after-market rims or wheels to be used in lieu of standard, military issue rims on HUMMVEES equipped with the CTIS. Moreover, the invention allows users to selectively disconnect tires from the CTIS without compromising the integrity of the CTIS. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an isometric view of a vehicle equipped with a typical CTIS. 
     FIG. 2 is an isometric view showing one embodiment of a CTIS according to the invention. 
     FIG. 3 is an isometric view of one embodiment of an air supply line that may be used in the system of FIG.  2 . 
     FIG. 4 is an isometric of an alternative embodiment of an air supply assembly that may be used in the CTIS of FIG.  2 . 
     FIG. 5 is an isometric view of another alternative embodiment of an air supply assembly that may be used in the CTIS of FIG.  2 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention is directed to an apparatus and method for releasably connecting a Central Tire Inflation System (CTIS) to the pneumatic tires of a motor vehicle. Specific details of several embodiments of the invention are set forth in the following description, and in FIGS. 2-5, to provide a thorough understanding of such embodiments. A person of ordinary skill in the art will understand, however, that the present invention may have additional embodiments, and that the invention may be practiced without several of the details described in the following description. 
     FIG. 1 shows a typical vehicle Central Tire Inflation System (CTIS)  10 , according to the prior art with the front of the vehicle in direction  11 . The system  10  comprises an electric air compressor  2  or an air compressor driven mechanically by the engine, and sending pressurized air to an air reservoir (not shown). From the air reservoir, the air is sent through tubes or pipes, such as  3  and  4 , to the tires  5 . The tubes  3 ,  4  communicate with the tires  5  through fluid couplings and tubes extending through the center of the drive shafts  12 . A control valve  6 , commonly located in the vehicle&#39;s cab, is used to selectively control the air pressure of the associated tires  5  of the vehicle. 
     Still referring to FIG. 1, the CTIS  10  further includes a rotary seal assembly  32  at the center of each rim or wheel  30 . This rotary seal assembly  32  provides for an airtight rotating joint in order to assure a connection between the air supply  2  and each of the tires  5  through the hub of each wheel  30 . A fitting  34  is threadably connected to the seal assembly  32 . The fitting  34 , while being airtight, is free to rotate about the wheel axis  13  and the seal assembly  32 . A supply line hose  36  is affixed is to the opposite end of the fitting  34 , and then threadably connected at  38  to a wheel inflation stem  40 . 
     Typically, the wheel inflation valve stem  40  for a CTIS HUMMVEE is not a conventional valve stem made of rubber with a Schrader valve therein, but is a solid, metal valve stem that is “thru-bolted” into the wheel  30 . This wheel inflation stem  40  generally does not contain a Schrader valve. As a result, a catastrophic tire failure causes the opposite tire to deflate also. 
     Turning now to FIG. 2, one embodiment of a CTIS system  50  in accordance with the proposed invention is depicted. As shown, a quick disconnect male fitting  52  is threadably attached to the rotary seal assembly  32 . The rotary seal assembly  32  receives compressed air from a supply tube that extends through the axle, as described in the foregoing discussion of the prior art CTIS system  10 . A female quick disconnect fitting  54  can then be coupled to the corresponding male fitting  52 . At the distal end of the female fitting  54  are two threaded recesses  56   a  and  56   b . Threadably affixed to recess  56   a  is a supply line assembly  58 . A valve stem assembly or “tank valve”  60  is threadably attached into the recess  56   b . The orientation of the supply line assembly  58  and the tank valve  60  are interchangeable into the recesses  56   a  and  56   b . A fitting  59  at the end of the supply line assembly  58  is threaded onto the inflation system  40 ′ when the CTIS  50  is in use. However, unlike the prior art inflation system  40  shown in FIG. 1, the inflation system  40 ′ is of conventional design containing a Schrader valve. The tank valve  60  contains a Schrader valve (not shown) within. Finally, a dust cap  62  can be threadably affixed to the open end of the tank valve  60  to protect the Schrader valve within the tank valve  60  from the environment. The tank valve  60  permits inflation of the tire by air sources other than the CTIS. 
     The fittings  52  and  54  may be comprised of any durable material suitable for the purpose, and could be made of brass or stainless steel for example. Moreover, the use of the mated quick disconnect fittings  52  and  54  allow for more freedom of rotation of the supply line assembly  58  of CTIS system  50  during wheel  30  rotation. 
     Referring to FIG. 3, another embodiment of the supply line assembly  100  includes a threaded male fitting  61  for screwing into the recess  56   a . An air supply line  64  is fluidly connected to the fitting  61 . A crimped or swaged member  62  provides a fluid tight connection between the supply line  64  and the fitting  61 . The air supply line  64  can be made of rubber or any other suitable material, that is capable of sustaining internal air pressures commonly associated with tire inflation. Alternatively, the supply line  64  may be made of wire-bound flexible hose or a reinforced plastic hose material, or even rigid metal tubing. A female threaded fitting  68  is fluidly connected to the opposing end of air supply line  64 . A crimped or swaged member  66  provides a fluid tight connection between the supply line  64  and the fitting  68 . With reference now to FIGS. 2 and 3, the female threaded fitting  68  contains a one-way check valve (not shown). compressed air from the a tire  5  of system  50  in the event that another tire is unable to maintain inflation due to a leak, puncture, or a blowout. If the system  40  optionally includes a Schrader valve, the one-way check valve may additionally include a plunger (not shown) that is structured to depress the Schrader valve in the wheel inflation system  40  so that the Schrader valve is maintained in an open state when the one-way valve and the system  40  are connected stem  40 , thereby permitting the tire  5  to be inflated by the CTIS. On the other hand, if the tire  5  were to go flat, the one-way check valve prevents loss of air from the CTIS  10  through the compromised tire  5 . This is especially true if there is no Schrader valve in the wheel inflation stem  40 . If however, there is a Schrader valve in the inflation system  40 , the supply line assembly  58  can be removed to isolate the tire  5  from the remainder of the CTIS  50  in the event of a leak in the CTIS  50 , which might be caused, for example, by a leak in another tire  5 . In such a case, the supply line assembly  58  need not contain a one-way valve. 
     As mentioned above, the fitting  68  is threadably attached to the wheel inflation system  40 . As a result of this configuration, the tire  5  may be inflated by the CTIS  50  and/or through the tank valve  60 . As also mentioned above, by disconnecting the quick release fitting  54  from the rotary seal assembly  52  or the fitting  68  from the wheel inflation stem  40 , the tire  5  can be isolated from the CTIS  50 . This prevents the opposite tire from going flat, for example, during changing of a flat tire. 
     Another embodiment of the supply line assembly  200  of CTIS system  50  is illustrated in FIG. 4 . Here, the supply line assembly  200  terminates in an elbow shapeded, threadable, female fitting  70  for attachment to the wheel inflation stem  40 . This arrangement accommodates a greater range of variations in wheel inflation stems  40 , particularly those parallel to the axis of tire rotation  13 , i.e., normal to the wheel  30 , such as found on the standard HUMMVEE CTIS compatible wheel  30 , as best shown in FIG.  2 . 
     Lastly, as shown in FIG. 5, another embodiment of the supply line assembly  300  of CTIS system  50  terminates in a female quick disconnect fitting  80  for connecting to the valve stem assembly  40 . The inner diameter (not shown) of the fitting  80  is such that it provides an airtight seal when connected to the wheel inflation stem  40 . By using the quick-disconnect fittings  54  and  80  together, the tire  5  can be more rapidly isolated from the CTIS  50  and spare tire changes made even more quickly. This is particular configuration also has the advantage of making any wheel  30  or wheel inflation stem  40  compatible with the HUMMVEE CTIS  10  as shown in FIG.  1 . 
     While various embodiments of the invention has been illustrated and described in detail herein, it will be apparent that changes and additions may be made therein and hereto without departing from the spirit of the invention, and which are encompassed within the spirit of the invention and the scope of the appended claims.