Air control system for pneumatic tires on a vehicle

Abstract: An air control system which is connected to the conventional air supply on a truck is continuously connected to the truck tires and provides equal pressure to all of the tires through a regulator. The air connection between the regulator and each tire is through a rotatable joint in the truck axles for allowing rotation of the wheels while connected to the air control system.

Description: Background of the Invention The present invention is directed to an air control system as defined by the features of the preamble of claim 1, for controlling the inflation pressure of tires on a vehicle, such as a truck-trailer. It is known that tires should be properly inflated for ease of control of the vehicle and consequently its safety, and to provide even wear and long life of the expensive tires. While the truck drivers may periodically check their tires, they frequently do not take the time or effort to insure that the tires are properly inflated and they are frequently unaware when an inflation problem occurs. In some instances, even a blowout on an 18 wheeler may remain unnoticed until the adjacent tire is ruined. From BE-A-673 200 there is known an air control system for a truck vehicle disclosing the features of the preamble of claim 1. This known system comprises an air supply, an air line connected therewith, an air connection including a check valve between a regulator and each tire for supplying regulated air pressure thereto, and a rotatable joint which is provided outside the axles to allow rotation of the wheels while being connected to the air control system. The rotatable joint of this system comprises a complicated mechanism of stator members and spring loaded seal rings provided within an axle cap mounted to the outside of the wheel rim and the air is supplied through a line extending through the non-rotating axle to the outside of the wheel to the rotatable joint in the axle cap and to the respective tires. Since the rotatable joint is provided outside the wheel within an axle cap mounted therewith, exchange of a wheel requires dismounting of the whole rotatable joint and is complicated. Moreover, since the rotatable joint is exposed to the outside of the wheel it can be damaged easily. It is the object of the present invention to provide an improved air control system for a truck vehicle which provides continuous air connection to the plurality of tires but can be easily disconnected to repair and replacement of the tires and which provides improved safety during operation. According to the present invention there is provided an air control system as defined by the features of claim 1. Preferred embodiments of the air control system are defined in the dependent claims. Other and further objects, features and advantages will be apparent from the following description of a presently preferred embodiment of the invention, given for the purpose of disclosure, and taken in conjunction with the accompanying drawings. Brief Description of the Drawings Fig. 1 is a fragmentary, perspective elevational view of the present invention installed in a truck-trailer, Fig. 2 is a fragmentary, perspective view of the connection of the air control system of the present invention to two tires at the end of an axle, Fig. 3 is an enlarged end elevational view illustrating the connection of the air control system to the two tires of Fig. 2, Fig. 4 is a fragmentary, elevational view, partly in cross section and schematic, illustrating the air connection through one type of axle such as a back axle of a truck-trailer, Fig. 5 is a fragmentary, elevational view, partly in cross section and partly schematic, illustrating the connection of the air supply system to a different type of axle, and Fig. 6 is an enlarged, elevational view illustrating the control box of the present invention. Description of the Preferred Embodiment Referring now to the drawings, and particularly to Fig. 1, the reference numeral 10 generally indicates a conventional vehicle, such as an 18-wheel truck-trailer, having a plurality of axles 12 and 14 with wheels having pneumatic tires. Thus, axle 12 includes two tires 16 and 18 at one end and axle 14 includes two tires 20 and 22 at one end. As is conventional, similar tires are at the second end of the axles 12 and 14. Such a vehicle 10 also includes an air supply 24 and an air line 32 from a pump (not shown) and an air tank 26 for supplying air pressure to the brakes on the vehicle 10. The above description of a vehicle 10 with pneumatic tires and a conventional air supply system is well known. The present invention is directed to providing an sir control system 30 which is continuously connected to all of the pneumatic tires including 16, 18, 20 and 22 on the vehicle 10 to provide an equal pressure thereby improving the safety of the vehicle 10, and to provide even wear and long life of the expensive tires. The air control system of the present invention is generally indicated by the reference numeral 30 and generally includes an air line 32 connected to the vehicle air supply 24, a control box 34 which includes an air pressure regulator 36, an air connection generally indicated by the reference numeral 38, between the regulator 36 and each tire 16, 18, 20 and 22, and a rotatable joint 40 or 40a in the air connection 38 for allowing rotation of the wheels while connected to the air control system 30. Referring now to Figs. 1 and 6, the air control system 30 of the present invention includes the air line 32 which is connected to the normal truck air supply 24. A typical truck air supply may have 120 psi air pressure. Preferably, the air line 32 includes a manual off/on valve 42 for manually connecting or disconnecting the air control system 30 of the present invention to the vehicle air supply 24. Additionally, the air line 32 may include a check valve 44 which allows the passage of the air through the air line 32 to the pressure regulator 36, but prevents reverse flow of air. The check valve 44 is for protecting the air pressure in the tires when the truck is shut down. The air pressure regulator 36 may be of any conventional type and is typically set at between 108-110 psi as this is the normal air pressure carried in the truck-trailer tires of an 18-wheel truck-trailer. One satisfactory type of air regulator is Model 56-110, sold by Air Drco. The air connection generally indicated by the reference numeral 38 between the pressure regulator 36 and each of the tires 16, 18, 20 and 22 includes various components and features which are useful and convenient in maintaining equal air pressure in each of the tires, allowing the tires to be easily repaired, and preventing disablement of the air supply 24, which is required for the air brakes on the truck. The air connection 38 includes an unloader valve 46 which is normally open, but closes in the event that the output air pressure from the pressure regulator 36 falls below a predetermined value. For instance, the unloader valve 46 may be set to close in the event that the pressure in the air connection 38 falls below 80 psi. This prevents any further loss of supply air from the supply system 24, thereby protecting the air supply 24 and allowing it to maintain sufficient air pressure to actuate the air brakes on the vehicle 10. One suitable unloader valve is No. 3X818, sold by Control Devices, Inc. In addition, a conventional air filter 48 may be provided in the air connection 38 to provide clean air to the system and prevent any particles from interfering with the operation of the air control system 30. Referring now to Fig. 4, in which a front or fixed axle 12 is shown, the air connection 38 is supplied from the outside of the axle 12 through a fixed line 50 which is preferably coaxially positioned in the axle 12 and through the wheel hub 52. The line 50 is connected to the rotatable connection (air union) 40 which is a rotatable joint which allows rotation of the end of the air supply connection as the tire rotates. One suitable type of rotatable joint is a rotatable union model 1115 sold by Deublin. Thus, the rotating joint (air union) 40 is connected through the fixed air line 50 on one side and the other side is connected to a rotatable connection which includes a tee 54 having first 51 and second 53 similar tire connections for two tires, such as 16 and 18. Thus connected to the outside tire, such as tire 16, is a connection 51 consisting of preferably a male 56 and female 58 connectible and disconnectible coupling (quick disconnect coupling) for conveniently disconnecting the tire 16 from the system 30 for replacement or repair. Also, the tire connection 51 includes a test valve stem 60 for testing the air in the tire 16. A flexible hose 62 completes the connection 51 to the valve stem of the outside of the tire 16. Preferably, the normal dill valve in the tires are removed and instead a conventional check valve, such as Model MJCV-1, sold by Control Devices, Inc. is included in the male connector 56 as such a check valve will be longer lasting than the normal dill valve. The tire connection 53 to the inside tire 18 is also connected to the tee 54 and includes similar parts to those in the tire connection to the tire 16 which are similarly numbered with the addition of the suffix "a". It is noted that the tire connections 51 and 53 are connected to the opposite sides of the rotating tee connection 54. While the tire connection 53 to the inside tire 18 may be slightly longer than the tire connection 51 to the outside tire 16, the tire connections 51 and 53 are generally balanced for rotation. While the tire connection 51 goes directly to the tire stem in the tire 16, the tire connection 53 goes through the tire 16 as best seen in Figs. 1 and 3. It is noted in Fig. 4 that the line 50 also extends towards the opposite ends of the fixed axle 12 to supply regulated air to the two tires and wheels at the other end of the axle 12. While the axle 12 described in Figs. 1 and 4 is fixed, the present invention may also be connected to and used with axles 14 having rotating shafts 70 (Fig. 5) therein driven by a conventional transmission 72 for driving wheel 74. In this case, an air passageway 76 is drilled coaxially through the rotatable shaft 70. The passageway 76 ends in a port 80 which is connected to an air union 40a which in turn is connected to the fixed air connection 38. The air union 40a includes an annular chamber 84 for supplying a continuous supply of air from the connection 38 to the air passageway 76. One suitable type of rotatable joint is the "Around-The-Shaft" union sold by Deublin. Thus, while the shaft 70 rotates, the union 40a remains fixed and supplies air to the tires 20 and 22. The tire connections 51 and 53 to the tires 20 and 22 are identical to the tire connections 51 and 53 in Fig. 4. In use, the air control system 30 of the present invention is installed in a vehicle 10 as described. The hand valve 42 is opened and air from the vehicle air supply 24 is supplied to the pressure regulator 36, at an inlet pressure of typically 120 psi. The outlet air pressure supplied from the pressure regulator to the air connection 38 is normally 108-110 psi. Thus, the air will flow through the air connections 38 through the rotatable joints (air unions) 40 and 40a, and to the rotating tee connections 54 to the tire connections 51 and 53 which are continuously connected to and continuously supply air to all of the tires 16, 18, 20 and 22 of the vehicle 10. The air is supplied through check valves in each of the tire connections 51 and 53. As long as the system operates satisfactorily, the unloader valve 46 will remain in the open position supplying regulated pressure to the tires. In normal operation, the system 30 will maintain all of the tires with equal pressure. If the operator desires to check the pressure in the tires, this may be done by testing at the valve stems 60 or 60a for the desired tire. In the event that one of the tires needs to be repaired or replaced, the manual valve 42 is closed disconnecting the system 30 from the vehicle air supply and the individual tires can be disconnected from the air supply system 30 by disconnecting the quick connect/disconnect couplings 56-58 or 56a-58a as appropriate. The remainder of the tires will remain inflated through their connected check valve in their individual tire connection. In the event that a blowout occurs, the air will, of course, be continued to be supplied to the blown out tire causing a drop in the output pressure from the pressure regulator 36. When the pressure in the air connection 38 drops to a predetermined value, such as 80 psi, the unloader valve 46 will close, thereby preventing loss of any further air from the vehicle air supply 24. If desired, an alarm system can be added to the vehicle 10 air supply, if there is not one, to indicate when the air supply falls below a predetermined amount. However, trucks 10 normally have gauges in the cab of the truck which already indicate the pressure in the air supply. This will provide a warning to the operator of a problem so that he can check the problem before the adjacent tire to the blown out tire is also damaged.

Claims: An air control system (30) for a truck vehicle (10) having a plurality of axles (12,14) with at least one wheel having a pneumatic tire (16,18,20,22) at each end of the axles (12,14) and said truck (10) having an air supply (24) comprising an air line (32) connected to the air supply (24), a pressure regulator (36) connected to the air line (32) for supplying substantially constant regulated air to the tires (16,18,20,22), an air connection (38) between the pressure regulator (36) and each tire (16,18,20,22) for supplying regulated air to each tire (16,18,20,22), said air connection (38) extends through the axles (12,14) and said air connection (38) includes a rotatable air union (40,40a) having first and second parts rotatable relative to each other, one of said parts connected to a fixed air line (50) in the air connection (38) and said second part connected to a rotatable air line (51,53,54) leading to the wheels for allowing rotation of the wheels while connected to the air control system (30), at least one check valve in the air connection (38) downstream of the pressure regulator (36), characterised in that said rotatable air union (40,40a) for each tire (16,18,20,22) is positioned inside the axles (12,14), and there is provided an unloader valve (46) in the air connection (38) downstream of the pressure regulator (36) and upstream of all of the lines to said tires (16,18,20,22), said unloader valve (46) being normally open for supplying air to all of the tires (16,18,20,22), but closes on a drop in outlet pressure shutting off air to all of the tires (16,18,20,22) for preventing further loss of air from the air supply (24). An air control system (30) according to claim 1, characterised in that the system includes a check valve (44) upstream of the regulator (36). An air control system (30) according to claim 1, characterised in that the system includes a non-threaded quick disconnect coupling (56 - 58) adjacent each tire (16,18,20,22).

Inventors: STECH CLYDE GILBERT, STECH, CLYDE GILBERT
Applicants: EQUALAIRE SYSTEMS INC, EQUALAIRE SYSTEMS, INC.
Application year: 1991
Main classification: B60C23
IPC codes: B60C23