Abstract:
A spent transmission fluid is drained from a transmission and replaced with new fluid. The transmission&#39;s converter forces the spent fluid into a spent fluid container, while air displaced by the entering spent fluid is forced into a second container holding a new replacement fluid. The second container is thereby pressurized and the new fluid is thus forced through an interconnecting conduit line into the dipstick tube so as to replace the spent fluid flowing out. The spent fluid leaving the transmission causes suction to appear at the dipstick tube which sucks the new fluid into the transmission. To assure that this suction is maintained, the dipstick tube is sealed so that the system is closed.

Description:
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 transmission 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 fist 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 transmission fluid replacement systems, but does not teach a system that may be installed into one of the coolant lines of the transmission without knowing direction of flow, and does not teach a closed and sealed system that forces new replacement fluid into the transmission by both suction from the draining spent fluid and by pressure of displaced air in a sealed spent fluid container. 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. 
     A spent transmission fluid is drained from a transmission and replaced with new fluid. The process occurs while the transmission is operating so that the transmission&#39;s converter forces the spent fluid into a spent fluid container, while air, displaced by the entering spent fluid, is forced into a second container holding a new replacement fluid. The second container is thereby pressurized and the new fluid is thus forced through an interconnecting conduit line into the dipstick tube of the transmission so as to replace the spent fluid flowing out. The spent fluid leaving the transmission causes suction to appear at the dipstick tube which sucks the new fluid into the transmission. To assure that this suction is maintained, the dipstick tube is sealed so that the system is closed allowing hands free operation. A flow directing device is used to assure proper fluid flow from the transmission or from the transmission&#39;s cooler. 
     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 the transmission system in such a manner that no exterior pump, other than the transmission pump, is required. 
     A further objective is to provide such an invention capable of quick and easy change of transmission fluid without excessive skill or supervision. 
     A further objective is to provide such an invention capable of system self pressurization for replacing transmission fluid. 
     A still further objective is to provide such an invention wherein the spent transmission fluid may be taken directly from the transmission line or from a transmission fluid cooler line without the necessity for checking in which direction the fluid is flowing. 
     A still further objective is to provide such an invention capable of replacing transmission fluid without spills and other potential damage to the environment because it is a closed and sealed system. 
     A still further objective is to provide such an invention capable of replacing transmission fluid without the aid of an external pump. 
     A still further objective is to provide hands free operation so that the fluid is less likely to come into contact with an operators skin. 
     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 schematic view of the preferred embodiment of the invention; and 
     FIG. 2 is a schematic diagram of a flow directing means thereof used with an automotive transmission system. 
    
    
     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 replacing transmission fluid in, for instance, an automotive vehicle such as a car, truck or bus, or in a stationary system such as a wind driven electricity generator. As shown in FIG. 1, a transmission  10  and a transmission fluid cooler  20  are interconnected for fluid exchange with a spent fluid container  30  for receiving a spent fluid  40  from the transmission  10  or from the cooler  20 ; and a new fluid container  50  which holds a new transmission fluid  60 . It should be noticed that no external pump is required in the present apparatus and method. It should also be noticed that in FIG. 1, the spent fluid  40  is flowing to spent fluid container  30  from cooler  20 . A means for directing fluid flow  70  provides two inlet orifices  72 ,  74  and an outlet orifice  76 , as shown in FIG.  2 . FIG. 2 shows, in schematic form, that fluid flow into either inlet orifice  72  or  74  pushes ball cock  71  in the direction of inflow to seal the opposing inlet. So as not to confuse the reader, ball cock  71  is shown in three positions; sealing inlet  72  at the left in FIG. 2, sealing inlet  74  at the right in FIG. 2, and in the center, a neutral position when no flow is present. Clearly, the ball cock is able to freely move between these positions depending on the direction of fluid inflow. In FIG. 1 it is shown that the flow directing means  70  is enabled for receiving fluid through inlet orifice  72  while discharging the fluid through the outlet orifice  76  to spent fluid line  94 , and further, while checking fluid flow through the other of the inlet orifices  74 . Flow through both of the inlet orifices  72 ,  74  is not possible in that flow through one of the orifices closes the other as can be seen in the schematic FIG.  2  and discussed above. It should be recognized that the flow directing means  70  may alternately be placed into transmission output line  92 , which is normally used to conduct the transmission fluid to the cooler  20  as shown in FIG.  1 . In this case, the spent fluid enters flow directing means  70  through inlet orifice  74  and exits from outlet orifice  76  to spent fluid line  94 . Also, in this case, the line  90  (cooler return line) remains intact between cooler  20  and transmission  10 . Flow directing means  70  receives spent fluid  40  and directs it to spent fluid line  94 , so that without knowing the direction of flow in the lines  90  and  92 , either line may be selected for use. This provides a significant advantage in the installation of the present apparatus in time saving and possible spills upon checking for fluid flow which is not necessary through the use of means  70 . 
     A means for sealing  80  is provided within a dipstick tube  12  of the transmission  10 , the sealing means providing a sealing means aperture  82  therethrough, enabling fluid flow through the sealing means  80 . Such a sealing means  80  may be a modified rubber tube cork or stopper as is well known in chemistry laboratories. A cooler return line  90  and a transmission return line  92  each are interconnected with one of the inlet orifices  72 ,  74  of the flow directing means  70 . A spent fluid line  94  is interconnected between the outlet orifice  76  of the flow directing means  70  and the spent fluid container  30 . A new fluid line  96  is interconnected between the new fluid container  50  and the sealing means  80 . A transfer fluid line  98  is interconnected between the spent  30  and the new  50  fluid containers. In this manner, the spent fluid  40  directly from the transmission  10  or from the fluid cooler flows to the flow directing means  70  and therefrom to the spent fluid container  30 , thereby forcing air from the spent fluid container  30  into the new fluid container  50  through the transfer line  98 , and thereby forcing the new fluid  60  from the new fluid container  50  directly into the transmission  10  via the new fluid line  96  through the sealing means  80 . Suction from the transmission  10  at the sealing means  80  further urges the new fluid  60  into the dipstick tube  12  and thus into the transmission  10 . The lines used herein are preferably flexible tube stock of a material impervious to transmission fluid. The various valves used in the present invention are well known in the art to those of skill. 
     Preferably, as shown in FIG. 2, inlet orifices  72 ,  74  of the flow directing means  70  are opposing check valves each enabling fluid flow toward the other, the outlet orifice  76  positioned between the check valves. 
     Preferably, the spent fluid  40  enters the spent fluid container  30  through an inlet port  32  positioned in the bottom of the spent fluid container  30 , and the air displaced within the container  30  is forced out of an outlet port  34  positioned at the top of the spent fluid container  30  as shown by arrows. 
     Preferably, the new fluid  60  exits the new fluid container  50  through an outlet port  52  positioned in the bottom of the new fluid container  50 , and the air from container  30  is forced into an inlet port  54  positioned at the top of the new fluid container  50 . 
     Preferably, a check valve  75  is positioned in the transfer line  98 , the check valve enabled by its orientation and function, as is well known in the art, for allowing fluid flow from the spent fluid container  30  to the new fluid container  50 , but preventing fluid flow in the reverse direction. In this case the fluid flow is that of air and not any of the transmission fluids. 
     Preferably, an inlet valve  35  is engaged in the transfer line  98  near the outlet port  34  of the spent fluid container  30 . This valve  35  provides a nipple  35 ′ and acts with two-way actuation enabling air exchange between the containers  30 ,  50  as described above, and also alternately enabling compressed air to be injected into the containers  30 ,  50 . The apparatus preferably further comprises a pair of drain valves  31  and  51 , one of the drain valves  31  engaged with the spent fluid line  94  and enabled for draining the spent fluid  40  from the spent fluid container  30 , the other of the drain valves  51  engaged with the new fluid line  96  and enabled for draining the new fluid  60  from the new fluid container  50 . 
     The present invention provides a method, using the above apparatus, for replacing transmission fluid as previously described. As defined above, the method includes inserting the flow directing means  70  into either the cooler return line  90  of the fluid cooler  20  or the transmission return line  92  of the transmission  10  with the dual inlet orifices  72 ,  74  receiving the spent fluid and the outlet orifice  76  of the flow directing means  70  interconnected with the spent fluid container  30  so it can receive the spent fluid  40 , interconnecting the new fluid line  96  between the new fluid container  50  which holds the new fluid  60 , and the sealing means  80 . Further, the method includes interconnecting the transfer fluid line  98  between the spent and the new fluid containers  30 ,  50 , directing spent fluid  40  from the transmission  10  or from the fluid cooler  20  to the flow directing means  70  by operating the converter of the transmission  10 , directing the spent fluid  40  from the flow directing means  70  to the spent fluid container  30 , directing air from the spent fluid container  30  displaced by the spent fluid  40  entering the container  30 , into the new fluid container  50  through the transfer fluid line  98 , and directing the new fluid  50  from the new fluid container  50  through the new fluid line  96  into the dipstick tube  12  of the transmission  10  for replenishing the spent fluid  40 . 
     Preferably, the method includes the step of sealing the new fluid line  96  in the dipstick tube  12 . 
     Preferably, the method includes the step of providing opposing check valves in the flow directing means  70  thereby enabling fluid flow from either one of the check valves toward the other one of the check valves; and positioning the outlet orifice  76  between the check valves for receiving flow from either one of the check valves. 
     Preferably, the method includes the step of receiving the spent fluid  40  into the spent fluid container  30  through an inlet port  32  positioned at the bottom of the spent fluid container  30  and forcing displaced air out of an outlet port  34  positioned at the top of the spent fluid container  30 . 
     Preferably, the method includes the step of receiving the air into the new fluid container  50  through an inlet port  54  positioned at the top of the new fluid container  50  and forcing the new fluid  60  out of an outlet port  52  positioned at the bottom of the new fluid container  50 . 
     Preferably, the method includes the step of placing the transfer check valve  75  in the transfer line  98 , and enabling the transfer check valve  75  for preventing fluid flow from the new fluid container  50  to the spent fluid container  30 . 
     Preferably, the method includes the step of placing the inlet valve  35  in the transfer line  98  and directing compressed air through the inlet valve  35  and into the spent fluid container  30  and the new fluid container  50  to force fluids therein to drain therefrom. The method includes the step of placing the pair of drain valves  31 ,  51  and engaging one of the drain valves  31  with the spent fluid line  94  thereby draining the spent fluid  40  from the spent fluid container  30 ; and engaging the other of the drain valves  51  with the new fluid line  96  thereby draining excess new fluid  60  from the new fluid container  50  as needed. 
     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.