Abstract:
Interconnecting a fluid interchange apparatus with a power steering system of a vehicle; pumping spent fluid from the power steering system into a fluid receiving container to compress air pressure therein; interconnecting, with a pressure actuated valve, the fluid receiving container and a replacement fluid container, the replacement fluid container holding a replacement fluid; automatically opening the pressure actuated valve when a selected amount of the spent fluid from the power steering system is transferred into the fluid receiving container resulting in an air pressure sufficient to open the pressure actuated valve; and draining, under the force of the sufficient air pressure, the replacement fluid from the replacement fluid container into the power steering system to replace the spent fluid in the power steering system with the replacement fluid.

Description:
RELATED APPLICATIONS 
     This is a continuation-in-part application of a prior filed application having Ser. No. 10/287,574 and file date of Nov. 4, 2002 now U.S. Pat. No. 6,688,340. 
     INCORPORATION BY REFERENCE: 
     Applicant(s) hereby incorporate herein by reference, any and all U.S. patents, U.S. patent applications, and other documents and printed matter cited or referred to in this application. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to automotive fluid systems and methods of use and more particularly to a power steering fluid exchange system and method of use. 
     2. Description of Related Art 
     The following art defines the present state of this field: 
     Allen, U.S. Pat. No. 4,408,960 describes a pneumatic method and apparatus for causing the rapid recirculation of a liquid between a plurality of containers by adjusting the pressure of a gas exerted within each of said containers to super-atmospheric, atmospheric and sub-atmospheric pressures, thereby avoiding the passing of the liquid through a mechanical flow-inducing pump. The containers are connected to each other by means of a liquid circulation system comprising a circulation conduit which includes a work station. A filled first container is subjected to super-atmospheric pressure to force the liquid into the circulation system while a second empty container is subjected to sub-atmospheric pressure to suck the liquid from the circulation system. After each container is empty and before it is subjected to sub-atmospheric pressure, for refilling purposes, it is exposed to atmospheric pressure to release the elevated pressure therefrom. The circulation system preferably incorporates a bypass conduit including a liquid replenishment tank and/or means for adjusting the temperature of the liquid. 
     Viken, U.S. Pat. No. 5,318,080 describes fluid changing in an automatic transmission by opening the cooler line and draining used fluid, at the flow of normal circulation, out of the cooler line from the transmission into a drain receptacle for receiving used fluid and simultaneously supplying fresh fluid, from a pressurized supply receptacle, into the cooler return line to the transmission at a similar controlled rate that is equal or greater than the rate of flow of the used fluid into the drain receptacle. 
     Knorr, U.S. Pat. No. 5,415,247 describes an automotive fluid exchange system wherein new fluid (such as power steering fluid) is simultaneously exchanged with the used fluid. First and second fluid conduits having first and second pumps disposed therein, respectively, provide the passageway between an engine compartment and a container for the new and used fluid, respectively. The two pumps are selectively actuatable by a respective, conventional toggle switch. Conventional jumper cables provide the power supply means to drive the pumps. 
     Payne, U.S. Pat. No. 5,427,505 describes an apparatus for extracting and injecting liquid coolant from and into a reservoir for an engine cooling system. The apparatus includes a storage tank for the liquid coolant, and an air pressure system for selectively applying fluid pressure to the tank either above or below atmospheric pressure. A hose connects the tank to the engine cooling system reservoir through a double shut-off-type coupling. One part of the coupling is connected to the reservoir, and the other, to the end of the transfer hose each having its own independent shut-off valve. When the coupling is connected, the valves in both components are opened and conversely when the coupling is disconnected, the valves automatically close. 
     Taguchi, U.S. Pat. No. 5,520,518 describes a method of transferring fluent material transferring the material from a first pressure tank to a fluent material transfer destination by supplying compressed gas to the first tank through a compressor. The compressed gas is retained in the first tank for reuse. Additional fluent material is drawn into a second pressure tank and is transferred therefrom to the fluent material transfer destination by supplying the compressed gas from the first pressure tank to the second pressure tank through the compressor. The compressed gas is further retained in the second pressure tank transferring fluent material from the first pressure tank. As the compressed gas is emptied from each tank to the other tank, additional fluent material is drawn into that tank. The cycle can be repeated on a continuous basis to transfer large quantities of fluent material. 
     Evans, U.S. Pat. No. 5,738,499 describes a fluid delivery/extracting device for extracting fluid from and delivering fluid to a reservoir of a vehicle. The device includes a cylindrical body formed from a tube, a bottom member and a top member. The top member comprises an annular member and a closure which closes the annular member. A pair of fittings extending through the closure, one of which has a portion extending below the closures top surface. A dip tube is applied to the this fitting and extends nearly to the bottom of the container. A first hose extends from the first fitting outer portion to a reservoir to be filled or emptied and is sufficiently long to extend to the bottom of the reservoir. A second hose extends from the second fitting and is connectable to any vacuum port of a vehicle if the device is to be used to empty the reservoir, or to a supply of pressurized air, if the device is to be used to fill the reservoir. The device makes it fairly simple to extract fluid from and deliver fluid to even hard to reach reservoirs, and reservoirs which are filled with highly viscous fluids. 
     Dixon et al., U.S. Pat. No. 5,806,629 describes a fail-safe transmission service machine allowing old ATF to be pumped out of a transmission while the vehicle engine runs, and responsively pumps a matching volume of new ATF into the transmission so that dry running of the transmission can not occur. If the supply of new ATF runs out or if power to the service machine is interrupted, the machine reverts to closed loop fluid circulation for the transmission. A hydraulic rectifier provides for universal connection of hoses between the transmission cooler fluid circulation loop of the vehicle and the service machine. An alternative embodiment of the machine allows for similarly fail-safe exchange of power steering fluid from a vehicle, and replacement of the old fluid with new power steering fluid. 
     Dixon et al., U.S. Pat. No. 5,853,068 describes an automotive fluid service machine for changing fluids such as automatic transmission fluid, power steering fluid, and engine coolant, including a cabinet with a unitary integral fluid reservoir defined by a, lower portion of the machine cabinet. This lower cabinet portion which integrally defines the fluid reservoir also provides a machinery deck to which the components of the machines are mounted. A cap portion of the cabinet provides a cavity for protecting the components mounted to the machinery deck and also provides a control panel for the machine in addition to providing fluid fill and drainage basins improving the convenience and safety of use for the machine. The safety of a service area is improved by the machine because a very low center of gravity for the machine reduces the risk of tipping of a machine and of spilling fluids. Thus, environmental concerns from such spills as well as the risk of personnel slips and falls on spilled fluids are reduced. 
     Dixon, U.S. Pat. No. 6,035,902 describes a fail-safe service machine for the power steering system of automotive vehicles including a pair of pumps each driven by electrical power from a vehicle under service, and a suction/delivery probe extending into the power steering system reservoir of the vehicle, both to remove old power steering fluid, and to simultaneously deliver new power steering fluid 
     Rome et al., U.S. Pat. No. 6,062,275 describes an apparatus and method of replacing old fluid in a transmission system by feeding clean fluid into the system from a clean fluid tank using a pump and draining the old fluid into a waste tank and using a processor to monitor the clean fluid pressure in the clean tank and the old fluid pressure in the waste tank and adjusting the pump&#39;s speed using the processor such that the old fluid is drained at substantially the same rate as the clean fluid is fed. 
     Rome et al., U.S. Pat. No. 6,247,509 describes and apparatus and method of replacing old fluid in a transmission system by feeding clean fluid into the system from a clean fluid tank using a pump and draining the old fluid into a waste tank and using a processor to monitor the clean fluid pressure in the clean tank and the old fluid pressure in the waste tank and adjusting the pump&#39;s speed using the processor such that the old fluid is drained at substantially the same rate as the clean fluid is fed. 
     Evans, U.S. Pat. No. 6,286,626 describes an automated system for changing the motor oil in an engine. The system includes a drain plug having a plurality of channels coupled with tubing that extends to a reversible pump. Tubing extends from the pump to both a used oil container and a new oil container. Check valves positioned at the entrance of each container restrict flow so the oil can flow only to the used oil container and only flows from the new oil container. Preferably, both containers are located in the trunk of the vehicle for easy access. In use, the pump is engaged to draw the used motor oil from the engine into the used oil container. Next, the pump is reversed to draw fresh oil from the new oil container into the engine. 
     Viken, U.S. Pat. No. 6,378,657 describes fluid changing in an automatic transmission by opening the cooler line and draining used fluid, at the flow of normal circulation, out of the cooler line from the transmission into a drain receptacle for receiving used fluid and simultaneously supplying fresh fluid, from a pressurized supply receptacle into the cooler return line to the transmission at a similar controlled rate that is equal or greater than the rate of flow of the used fluid into the drain receptacle. 
     Betancourt et al., U.S. Pat. No. 6,382,271 describes an apparatus and method of replacing old fluid in a transmission system by feeding clean fluid into the system from a clean fluid tank using a pump and draining the old fluid into a waste tank and using a processor to monitor the clean fluid pressure in the clean tank and the old fluid pressure in the waste tank and adjusting the pump&#39;s speed using the processor such that the old fluid is drained at substantially the same rate as the clean fluid is fed. 
     The prior art teaches the use of carts for providing automotive maintenance and especially in the field of power steering fluid exchange, but does not teach a system with the combination of features and automated controllability of the present invention. The present invention fulfills these needs and provides further related advantages as described in the following summary. 
     SUMMARY OF THE INVENTION 
     The present invention teaches certain benefits in construction and use which give rise to the objectives described below. 
     An apparatus for changing power steering fluid in an automotive power steering system, uses the components of an fluid receiving container; an fluid supply container; a utility fluid pump, a pressure actuated fluid valve; and, a fluid conducting means. The components are arranged such that air is compressed in the fluid receiving container by entry of spent power steering fluid and builds to open the pressure actuated valve when about 80-90 percent of the spent fluid has been drawn out of the power steering system, so as to drive replacement power steering fluid into the power steering system, replacing the spent fluid. 
     A primary objective of the present invention is to provide an apparatus and method of use of such apparatus that provides advantages not taught by the prior art. 
     Another objective is to provide such an invention capable of moving fluids between containers and an automotive power steering system in such a manner that when a selected percent of the spent fluid is removed, only then, will replacement fluid be driven into the power steering system. 
     A further objective is to provide such an invention capable of quick and easy change of power steering fluid without excessive skill or supervision. 
     A further objective is to provide such an invention capable of system pressurization used for remote, off-site, draining of power steering fluids. 
     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, by way of example, the principles of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawing illustrates the present invention. In such drawing: 
     FIG. 1 is a perspective view of the preferred embodiment of the invention; 
     FIG. 2 is an exploded perspective view of FIG. 1, showing the internal fluid conductors thereof and their interconnecting hardware elements; and 
     FIG. 3 is a schematic diagram thereof. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The above described drawing figures illustrate the invention in at least one of its preferred embodiments, which is further defined in detail in the following description. 
     The present invention is an apparatus for changing power steering fluid in an automotive power steering system. Fluid is shown with cross-hatching in FIG. 2, but not in the interconnecting hoses. The fluid is referred to as “spent fluid” which is replaced by the method of this invention, and as “replacement fluid,” which is substituted for the spent fluid. The vehicle&#39;s fluid reservoir is shown in FIG.  2  and identified with numeral  33 . The vehicle&#39;s power steering pump is not shown, but it pulls (pumps) fluid from the reservoir  33  to the power steering unit, also not shown, through tube  62 , and pushes the fluid back to the reservoir  33  through tube  64 . 
     FIG. 2 shows the operating components of the invention including, a fluid receiving container  10 , a fluid supply container  20 , a utility fluid pump  30  which may be of any common type capable of pumping both air and a viscous liquid such as power steering fluid, a pressure actuated fluid valve  40 , and fluid conducting conduits  15 ,  16 ,  16 ′,  17 ,  21 ,  32  which are preferably plastic tubing of the type that is reinforced so as to prevent bulging under pressure and collapse under vacuum. The containers  10  and  20  are constructed so that fluids, including air, can only flow into and out of the containers via their ports. The interconnections between containers  10 ,  20  and the fluid conducting conduits are tight so as not to leak when subjected to the pressures necessary for operation of the invention as herein defined. Such construction is well known in the art and is of critical importance here as will be shown. The components of the invention are arranged such that fluids, both air and power steering fluid are forced to flow in the apparatus under pressures created by fluid pump  30 . When the invention apparatus is engaged with the reservoir  33 , as shown, spent fluid in the vehicle&#39;s power steering system is pumped from reservoir  33  by suction in tube  35  and line  32 , into container  10  through check valve CV. Drain valve  31  is closed at this time. The novelty of this arrangement is that spent fluid flows into container  10  and this causes air in container  10  and line  16  to be slightly compressed because the system is tight, so that pressure in container  10  rises. Shutoff valve  80  is not open to tube  17  at this time. When a selected amount of the spent fluid from the vehicle&#39;s power steering system has flowed into container  10  its pressure and that in tube  16  reaches a level that automatically opens pressure actuated valve  40 , i.e., valve  40  is adjustable and set for a selected pressure. Such pressure actuated valves are very well known in the art and are notoriously used as pressure relieve valve. When valve  40  opens, pressure in container  10  is relieved into container  20  which forces the flow of replacement fluid from container  20  into reservoir  33  through tube  21  and valve  31 ′ which is open at this time. The sizes of the containers  10 ,  20  and of the tubes are such that 80-90% of spent fluid in the power steering system is removed before new replacement fluid starts to enter. One of skill in the art would have the capability to configure the tube sizes and lengths so that pressure adjustment at valve  40  is capable of accomplishing this result. As noted in FIG. 2, valve  40  is adjustable as to the pressure differential between tubes  16  and  16 ′ at which it will open. With this facilitation, it is quite simple to adjust valve  40  to open when a selected amount of the spent fluid has been removed from reservoir  33 . That is, upon first trials of the system, when the selected amount of spent fluid has been pumped from the power steering system, valve  40  is adjusted to open at the pressure differential that exists at that time between tubes  16  and  16 ′. This setting may thereafter remain unchanged for the invention to operate in the same manner in subsequent uses, assuming that the volume of each subsequent power steering system remains nearly the same. This is a critical and novel aspect of the invention and clearly results in a benefit of significant value, i.e., only 10-20% of the spent fluid is left to mix with replacement fluid. 
     In an alternate embodiment of the invention, valve  40  is not used. However, the same result is accomplished by sizing and positioning the tubes  16 ,  16 ′ and  21  and the containers  10 ,  20  such that the same result as described above is accomplished. Experimentation with tube conductances, pumping pressures and container volumes and relative elevational positions can easily converge on a system solution that operates without the valve  40  to achieve delayed fluid flow from the replacement container  20  relative to flow into the spent fluid container  10 . FIG. 1 shows a system that provides the requisite configuration to achieve the objectives defined. 
     Removal of the spent fluid and insertion of the replacement fluid is accomplished without supervision; basically automatically. The process is conducted while the engine of the vehicle is running so that the fluid is drawn off and replaced in a continuous manner, e.g., while circulating through the vehicle&#39;s power steering system via lines  62  and  64  respectively. This has the advantage of assuring that most of the spent fluid is extracted from the system prior to inserting the replacement fluid. The pump  30  may be of any type capable of pumping fluid, and as shown in FIG. 2 it is preferably driven by a source of compressed air (shop air) through a regulator  70 . Preferably the suction line tube  35  terminates with a magnetic suction nozzle  35 ′ for capturing metal finds in the fluid. Such metal finds, i.e., metallic dust and other particles often tend to clog the power:steering lines and valves so that capture of this material is of importance. The magnetic suction nozzle comprises a steel screen mounted on the end of the suction tube  31  the steel screen stretched across a doughnut shaped magnet so that the entire screen provides magnetic attraction to metal particles in the fluid. During fluid flow through the screen, the metal particles adhere to the screen and may later be manually removed. 
     Shutoff valve  80 , enables the use of shop air to pressurize containers  10  and  20  when necessary for draining fluids therefrom. To accomplish this, shop air is directed through regulator  70  and valve  80 ′ into tube  17  to pressurize the containers  10 , and/or  20  and at this time valves  31  and  31 ′ are closed. Relief valve RV is used to assure that excessive pressure does not appear in tube  17 . The tube assembly including suction tube  35  and delivery tube  36  is a simple, light weight assembly which is manually placed into reservoir  33  during fluid replacement, and removed from reservoir  33  for draining containers  10  and/or  20 . With this assembly removed from reservoir  33  and placed into a disposal container (not shown) and with the opening of wither or both drain valves  31  and  31 ′ (depending on which container is to be drained), the containers  10  and  20  are drained directly. The step of draining the containers  10 ,  20  is preferably accomplished by closing valves  31  and  31 ′, pressurizing the containers  10  and  20  and then closing shutoff valve  80  thereby isolating containers  10 ,  20  while they are under pressure, whereupon the system (all shown in FIG. 2 except for vehicle reservoir  33 ) is then moved to a drainage site for disposal of the fluids, wherein the fluids in containers  10  and  20  are forced out by the pressure held in containers  10  and  20  through the valves  31  and/or  31 ′. No assistance from shop air is required for this forced draining. An alternate method of draining container  10  is to provide a two-way drain valve at point “A” in tube  15 . Such a two-way drain valve in tube  15  at point “A” is plumbed to allow, in its first valve position, free fluid flow from pump  30  to container  10 , and in its alternate valve position, drainage of container  10 . Container  10  would be pressurized as described above prior to such draining. 
     In the preferred embodiment, containers  10  and  20  are about two feet in length and four inches in diameter, and the fluid tubes are {fraction (5/16)} or ⅜ inch inside diameter. The pressure actuated valve  40  is set to open at a specified pressure in the range of 3-6 psi, and this combination has been shown to automatically extract about 80-90% of the spent fluid in a typical automotive power steering system which holds about 2 quarts of fluid, prior to starting delivery of the replacement fluid. Other combinations of container and tube sizes and length can be used in the present invention just as well, and the opening pressure at pressure actuated valve  40  can be set to start delivery of the replacement PS fluid at any desired stage in the process. 
     The method of the present invention further comprises the following steps for determining and controlling the amount of replacement fluid delivered to the system. These steps include: positioning the jointly engaged suction line tube  35  and the delivery tube  36 , into the reservoir  33  of the power steering system, the suction line tube  35  positioned for sucking the spent fluid out of the reservoir  33  to the spent fluid container  10 , and the delivery tube  36  is positioned for delivering the replacement fluid to the reservoir  33  from the replacement fluid container  20 ; and determining the amount of replacement fluid delivered to the reservoir  33  by placing the tubes  35 ,  36  alternately and cyclically adjacent to a bottom surface  33 ′ of the reservoir  33  until the reservoir is empty, or nearly empty, and at an upper most position  33 ″ in the reservoir  33  until the reservoir  33  is filled. If the reservoir holds a total of one quart, then delivering the replacement fluid to an empty reservoir  33  until it is filled results in a one quart delivery, and then sucking the reservoir  33  until empty again and refilling it results in a two quart delivery, and so on. 
     While the invention has been described with reference to at least one preferred embodiment, it is to be clearly understood by those skilled in the art that the invention is not limited thereto. Rather, the scope of the invention is to be interpreted only in conjunction with the appended claims.