Patent Application
20130146193
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1. Field of the Invention
The present invention relates to pressure balancing systems between a set of dual tires on vehicles. More particularly, the present invention the relates to a valve arrangement for controlling the air pressure between such dual tires. Additionally, the present invention relates to tire pressure equalization systems which serve to maintain equal pressure between the dual tires and for blocking the release of air pressure in the event of deflation of one of the dual tires.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
Load hauling trucks, earthmoving equipment, and the like are often propelled by sets of dual tires. Machines of this nature typically have a set of dual tires mounted on each end of an axle. Each set of dual tires includes an inner tire and an outer tire. Each tire is mounted on a separate rim. The inner rim and tire are attached to an indboard end of the wheel assembly and the outer rim and tire are attached to an outboard end of the wheel assembly. The wheel assembly rotates about an axle via a pair of wheel bearings. One of the wheel bearings is located near the indboard end of the wheel assembly and other is located near the outboard end of the wheel assembly. The wheel bearings are designed and positioned on the axle to carry a predetermined portion of the load (gross weight) of the machine. The load is then transferred through the tires to the ground. During normal operation of the machine, the air pressure in the inner and outer tires may not be equal. This can be caused by an improper inflation, uneven heating of the tires, uneven forces bearing upon the tires during operation, or an air leak in either of the tires.
Unbalanced or improper air pressure between the inner and outer tires can cause a portion of the load on either wheel bearing to shift from one bearing to the other. These unbalanced loads can cause excessive wear on one or each of the tires or improper loading on one or each of the wheel bearings. Repeated excessive loading may cause permanent damage to the bearings.
It is possible that each of the tires could be connected together by a hose or a tube passageway so as to allow for equalization of air pressure. However, a sudden loss of pressure in either tire would result in loss of pressure in both tires. As such, it is desirable that, in the event of deflation of one of the tires, that air is prevented from flowing between the inflated tire to the deflated tire, thus causing a deflation of both of the tires.
One particular application of such co-axial tires is heavy dump or haul trucks. In particular,
For example, mine haul trucks carry significant loads. It is not uncommon for these loads to be in excess of 150 tons. As a result, the first set 12 of tires and the second set 14 of tires are used so as to distribute the load. These tires that are utilized are tubeless and large. Generally, the wheels are in excess of nine feet in diameter. They also operate under extreme conditions and can be in constant use. As a result, the tires are prone in carrying debris and particulate matter, such as rust or rocks.
Due to the significant loads carried by the vehicle 10, any pressure imbalance in the co-axial tires can cause significant problems. For instance, where a pair of co-axial tires are of pressures between 80 p.s.i. and over 100 p.s.i., there is a significant imbalance in the respective load and therefore how each tire performs. In this situation, with a total load of 110 tons, 42 tons would be distributed on the tire having a 80 p.s.i. of pressure and 72 tons on the tire having over 100 p.s.i. Therefore, one of the tires is working almost twice as hard as the other tire. The air flow caused by this imbalance results in an increase in tire temperature. This can dramatically increase wear and tear on the tires. In the worst case, the temperature may reach the liquefaction temperature of the tire rubber. If this occurs, the tire can be irreparably damaged and must be replaced.
These large tires for the mine or haul trucks are very scarce. The tires are of significant cost, commonly in excess of $75,000 each. Therefore, any improvement in the life of such a tire is advantageous.
In the past, a verity of patents have relating to tire pressure equalization system and systems for monitoring such tire pressure. For example, U.S. Pat. No. 2,445,547, issued on Jul. 20, 1948 to H. N. Wheeler, is an early patent relating to a dual tire valve. This pressure equalization device includes a valve body, a pair of aligned valve cappings having opposed seats communicating with the body and a single valve member. The valves carried by the member are adapted to coact with the seats and are disposed such that only one valve may be seated at a time. There is a means to admit air between the valves. A means is responsive to the admission of air between the valves so as to hold both of the valves off their seats.
U.S. Pat. No. 3,302,682, issued on Feb. 7, 1967 to A. A. Berg, shows a tire pressure device that has an elongated tubular housing, a chamber at one end of the housing, a filler opening communicating with the chamber, a pair of spaced outlets communicating with the chamber, a second chamber in the housing, a piston receptacle in the second chamber, and a passage communicating between the chambers on one side of the piston. A yielding means is on the other side of the piston and engages the piston so as to urge the piston toward the passage. A hollow cylindrical member substantially fills the second chamber. This cylindrical member slidably receives the piston. The housing has an opening overlying a portion of the cylindrical member. A plurality of annular flanges are spaced longitudally on the shaft and engage the inner surface of the cylindrical member so as to center and guide the shaft.
U.S. Pat. No. 3,454,034, issued on Jul. 8, 1969 to H. L. Dobrikin, shows a pressure system for a dual tire set that is operable to maintain a pressure balance between the tires above a predetermined minimum pressure. A valve housing is provided with a plenum chamber having a plunger slidable therein. The plunger has a bore extending axially therethough with a tire filling valve in one end and radially extending ports in the other end. A ball member is movably positioned in the bore to coact with the bore and ports for relatively quick inflation and slow deflation of the tire. An exhaust passage is provided in the housing and is controlled by a biased open exhaust valve which is moved to a closed position by engagement therewith of the plunger at temperatures above a predetermined minimum. Passages are provided in the housing so as to communicate the plenum chamber with the tires. Conduits connect the passages with the tires. These conduits each have a protection valve therein which maintains its associated tire valve by engagement therewith so long as pressure in the system is above a predetermined minimum but move out of engagement with its associated tire valve allowing the valve to close when the pressure in the system falls below the minimum. This disrupts communication between the tires. At pressures below the minimum, the exhaust valve is opened by its biasing means so as to establish atomospheric pressure and the plenum chamber.
U.S. Pat. No. 3,717,030, issued on Feb. 20, 1973 to McGhee et al., shows a tire pressure indicating apparatus for monitoring tire pressures on a vehicle. Individual hub units are mounted on each wheel unit. The hub units include a radio transmitter which is positioned by the vehicle operator. For dual wheel units used on heavy-duty vehicles, a common bellows responds to the lower pressure of the two tires to indicate the lower pressure on the gauge and transmit the fault signal. The dual wheel unit can include a pair of bellows means for actuating separate visual gauges for the two tires. The two bellows mechanisms energize a common transmitter. The hub unit can include valve for equalizing tire pressures.
U.S. Pat. No. 4,421,151, issued on Dec. 20, 1983 to W. Stumpe, describes a tire-pressure regulating system in which the air pressure in the vehicle tires can be varied while driving. The tires are connected to supply lines in which rotor connections, control valves, flow restrictive elements and an adjustable regulating valve are disposed. A relay valve and an axle valve are incorporated following the regulating valve. An acceleration of the tire equalization process occurs by guiding the supply line in and at the axle valve in a particular manner.
U.S. Pat. No. 4,658,644, issued on Apr. 21, 1987 to Coesfeld et al., teaches a manometer device for continuous monitoring of the air pressure in vehicle tires. This device includes manometric capsule and an electrical indicator device. A flatly conical membrane with a cylindrical projection is arranged transversely through the interior space of the manometric capsule. A permanent magnet is inserted in this projection. The membrane divides the interior space of the manometric capsule into two chambers. One chamber is stressed with a nominal pressure. The other chamber is connected to the pressure space of a vehicle tire. A stationary sensor, which is associated with the manometric capsule, responds to linear magnetic field variations and transmits the latter to a terminal.
U.S. Pat. No. 5,253,687, issued on Oct. 19, 1993 to Beverly et al., shows a vehicle central tire inflation system. The system includes an air control circuit having a positive pressure air source, a vacuum pressure air source, a central control unit, a vehicle speed sensor, and a command/display console. The control circuit includes valves and a conduit assembly for controlling communication of the positive and vacuum pressure to the wheel valve assemblies mounted on each wheel. A vent valve effects rapid closing of a valve device in each wheel valve. Each wheel valve includes a valve device providing substantially unrestricted air flow from the conduit assembly to the wheels when the valve device is open and provides restricted air flow from the wheels to the conduit assembly to ensure closing of the valve device when the conduit is vented.
U.S. Pat. No. 5,302,939, issued on Apr. 12, 1994 to Downs et al., provides a dual tire equalizer having remote indicator. In particular, the dual tire equalizer has a diaphragm with an axial probe actuating or not actuating a switch in a radio frequency transmitter circuit mounted on the wheel. The transmitter sends a signal varying, depending on the condition of the switch. A radio frequency receiver on the vehicle responds to the signal and issues appropriate information to the driver concerning conditions of the equalizer.
U.S. Pat. No. 5,307,846 issued on May 3, 1994 to Heinemann, describes a tire pressure equalizer which gives motorists a simple, low-cost way to adjust and balance the pressure within the individual tires of the vehicle without accidentally exceeding the maximum pressure level of the tires. The apparatus interconnects the four tires. A pressure gauge and a conventional tire air valve permit the internal air pressure of all four tires to be adjusted uniformly from one air source through a commercial connector and a specially-designed shut-off valve and to be disconnected without a loss of air in any of the four tires. If a pre-set air pressure level has been exceeded while air is being pumped into the tires, a safety air pressure-relief valve, coupled to a whistle, is triggered so as to notifying the motorist of this condition.
U.S. Pat. No. 6,457,502, issued on Oct. 1, 2002 to Bell et al., discloses a dual tire pressure balance system for maintaining equal air pressure in a pair of tires on a work machine. This system has a valve body with a pair of piston chambers. A piston is reciprocatably positioned within each piston chamber. The pistons are biased toward a first closed end of the piston chambers. The closed end of each piston chamber is connected by a passageway to one of the tires. Each piston chamber is additionally fluidly connected to the other piston chamber. When the air pressure in each tire is above a predetermined amount, the pistons are moved away from the closed end of the piston chamber and air flow is permitted between the piston chambers thereby balancing the tire pressures. If the pressure in either tire is below the predetermined minimum, the piston in that respective piston chamber moves toward the first end to block, airflow between the piston chambers.
U.S. Pat. No. 7,555,903, issued on Jul. 7, 2009 to Tarasinski et al., teaches a tire pressure regulating systems for regulating the pressure of tires mounted on a vehicle. The vehicle has an engine with a turbocharger which is a compressed air source for the pressure regulating system. The turbocharger has a variable geometry in order to supply a sufficiently high pressure.
It is an object of the present invention to provide a system which effectively balances air pressure between dual tires.
It is another object of the present invention to provide a system which blocks air flow in the event of deflation of one of the tires of the dual tire system.
It is another object of the present invention to provide a system whereby pressure between a pair of tires in a dual tire system remains constant regardless of the force or temperature affecting one of the tires.
It is still a further object of the present invention to provide a system which can be retrofitted to a dual tire system.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.
The present invention is a tire pressure equalization system for controlling air pressure between a first tire and a second tire. This system includes a housing having a bore extending therein. A first air passageway has an end opening to an interior of the bore. The first air passageway is suitable for connection to the first tire. A second air passageway has an end opening to an interior of the bore. The second air passageway is suitable for connection to the second tire. A valve is in the bore. The valve is movable between a first position in which the first air passageway communicates with the second air passageway in the bore and a second position that blocks communication between the first air passageway and the second air passageway.
In the preferred embodiment of the present invention, the valve is slidably positioned in the bore. In particular, in this preferred embodiment of the present invention, the valve is a shuttle valve having a wide diameter portion and a narrow diameter portion. The wide diameter portion is positioned against a wall of the bore. The narrow diameter portion is aligned with the first and second air passageways in the first position. The wide diameter portion is aligned with at least one of the first and second air passageways in the second position.
Also, in the preferred embodiment of the present invention, the housing has a first cylindrical area at one end of the bore and a second cylindrical area at an opposite end of the bore. The valve has a first rod extending through the first cylindrical area and a second rod extending through the second cylindrical area. A first piston is affixed to the first rod and has a periphery adjacent a wall of the first cylindrical area. A second piston is affixed to the second rod and has a periphery adjacent a wall of the second cylindrical area. The first cylindrical area has a shoulder adjacent to the bore. The second cylindrical area also has a shoulder adjacent the bore. A first spring has one end bearing against the first piston and an opposite end bearing against the shoulder of the first cylindrical area. A second spring has one end bearing against the second piston and an opposite end bearing against the shoulder of the second cylindrical area.
Also, in the preferred embodiment of the present invention, a third air passageway has an end opening to an interior of the first cylindrical area on a side of the first piston opposite the valve. The third air passageway is suitable for connection to the first tire. A fourth air passageway has an end opening to an interior of the first cylindrical area on a side of the piston opposite the third air passageway. The fourth air passageway is suitable for connection to the second tire. A fifth air passageway has an end opening to an interior of the second cylindrical area on a side of the second piston opposite the valve. The fifth air passageway is suitable for connection to the second tire. A sixth air passageway has an end opening to an interior of the second cylindrical area on a side of the second piston opposite the first air passageway. The sixth air passageway is suitable for connection to the first tire.
In the preferred embodiment of the present invention, a first air channel has one end opening on one side of the housing and an opposite end suitable for connection to the first tire. A second air channel has one end opening on one side of the housing and an opposite end suitable for connection to the second tire. A third air channel opens on the one side of the housing. The third air channel is in communication with the first air channel and the second air channel. A first one-way valve is positioned on the first air channel so as to allow air to pass through the first air channel to the first tire and for preventing air from passing from the first tire. A second one-way valve is positioned in the second air channel so as to allow air to pass through the second air channel to the second tire and for preventing air from passing from the second tire. A first air pressure sensor is cooperative with the first air channel so as to sense air pressure in the first tire. A second air pressure sensor is cooperative with the second air channel so as to sense air pressure in the second tire.
In this section, although the preferred embodiment is described with specificity, it is important that various other embodiments of the present invention can be made within the scope of the present invention. As such, such statements under this section should not be construed as, in any way, limiting of the scope of the present invention. Quite clearly, variations on the particular details of the structure identified under this section can be made within the scope of the present invention without departing from that which is claimed.
Referring to
The housing 28 includes an opposite side 36. As can be seen, there is a first air channel 38, a second air channel 40 and a third air channel 42 extending outwardly from the side 36. The first air channel 38 is suitable for inflation of the first tire. The second air channel 40 is suitable for inflation of the second tire. The third air channel 42, as will be described hereinafter, is communication with the first air channel 38 and the second air channel 40 so as to simultaneously inflate each of the first tire and the second tire. A first air pressure sensor 44 and a second air pressure sensor 46 are in cooperative with the first air channel 38 and the second air channel 40, respectively. The air pressure sensors 44 are suitable for electronically monitoring air pressure of the first tire and the second tire.
The third air channel 42 is communication with the first air channel 38 and the second air channel 40. The third air channel 42 is connected by conduit 44 to each of the first air channel 38 and the second air channel 40. If it is desired to simultaneously inflate both the first tire and the second tire, air pressure can be introduced into the third air channel 42. This will cause the one-way valves 50 and 52 to suitably open so as to allow air flow to pass through the air channels 38 and 40 and into the tires. If the third air channel 42 is not used, then the valves 50 and 52 will suitably close the channels 38 and 40 so as to prevent air from flowing from the tires outwardly of the third air channel 42.
The first air pressure sensor 44 is illustrated as connected to the first air channel 38. The second air pressure sensor 46 is illustrated as connected to the second air channel 40. The pressure sensors 44 and 46 are mounted downstream of the respective one-way valves 50 and 52. As such, the air pressure sensors 44 and 46 continuously monitor air pressure within the tires.
In
In
In
The fifth air passageway 98 is shown by connected by line 140 to the second tire 84. As such, air, under pressure, will fill the space 142 on the side of the piston 74. Air from the first tire 82 will flow through line 144 into the space 146 on the opposite side of the piston 74. As such, the spring 148 is suitably compressed so as to be balanced such that the narrow diameter portion 90 of the valve 68 resides in alignment with the first air passageway 30 and the second air passageway 32.
As can be seen in
The foregoing disclosure and description of the invention is illustrative and explanatory thereof. Various changes in the details of the illustrated construction can be made within the scope of the appended claims without departing from the true spirit of the invention. The present invention should only be limited by the following claims and their legal equivalents.
