Abstract:
Automotive service equipment for brake fluid exchange includes a central unit having a controller for operating the equipment and a communication module for wirelessly communicating with each of a plurality of remote bleed modules to control bleeding brake fluid from respective brake bleeders of a vehicle connected to the modules. The brake fluid from the brake bleeders is stored in containers in the modules for later removal. When disconnected from the brake bleeders, the modules are moved to docking stations on the central unit for emptying brake fluid from the module containers and vacuum charging the containers for brake bleeding. The automotive service equipment and related method of performing brake fluid exchange in an automotive vehicle avoid the use of hoses for returning the waste fluid to the central unit thus reducing the problem of storage and handling of such hoses and spillage of residual fluid left in the hoses.

Description:
RELATED APPLICATION 
     This application is a divisional application of application Ser. No. 11/832,119, filed Aug. 1, 2007 now U.S. Pat. No. 8,215,343, the disclosure of which is hereby incorporated by reference. 
    
    
     TECHNICAL FIELD 
     The present invention is an improved automotive service equipment for brake fluid exchange having a wireless brake bleeding system. A method of performing brake fluid exchange in an automotive vehicle using the equipment is also disclosed. 
     BACKGROUND AND SUMMARY 
     One of the current problems with all commercially available automatic brake bleed systems is the handling and entanglement of the hoses. Most machines require six hoses—one for emptying the master cylinder, one for filling and pressurizing the master cylinder (these are separate to minimize intermixing of old and new fluids), and one each for removal of the fluid from each of the four individual brake bleeder locations on the vehicle and returning the waste fluid to the unit. Storage and handling of this many hoses is an issue, and in addition to spillage from residual fluid left in the hoses, they frequently become entangled, resulting in operator frustration and lost time to untangle them before the next use. 
     One aim of the present invention is to provide an improved automotive service equipment for brake fluid exchange which avoids or reduces such problems with conventional automatic brake bleed systems. Instead of returning the waste fluid from each of the brake bleeders via a hose to the main unit as in the known commercially available automatic brake bleed systems, according to the invention the waste fluid from the brake bleeders is stored in at least one, and preferably in a plurality of remote bleed modules at respective ones of the brake bleeders for later removal. These volumes of waste fluid are relatively small, less than 12 ounces. Waste fluid is removed when the modules are docked with a central unit of the automotive service equipment at the end of the service. The modules are controlled remotely by the central unit through radio frequency or similar wireless technology. 
     More particularly, an automotive service equipment for brake fluid exchange according to the invention comprises a central unit including a controller for operating the equipment for exchanging used brake fluid in a vehicle with new brake fluid. The central unit has means for wirelessly transmitting signals to control brake bleeding during brake fluid exchange. At least one remote bleed module is provided. The module includes a fluid passage for connection to a brake bleeder of a vehicle for conveying brake fluid from the brake bleeder during brake fluid exchange. The module further includes a valve for opening and closing the fluid passage, a container for receiving and storing for later removal brake fluid conveyed through the fluid passage when the passage is opened by the valve, and means responsive to the wirelessly transmitted signals from the central unit for opening and closing the valve. 
     The container in the remote bleed module in the disclosed example embodiment of the invention is a sealed container capable of holding a vacuum charge and brake fluid. A plurality of remote bleed modules for connection to respective ones of a plurality of brake bleeders of a vehicle to be serviced are provided in the example embodiment. The controller of the central unit operates the remote bleed modules for bleeding brake fluid from the plurality of brake bleeders sequentially during servicing a vehicle. 
     The central unit further includes at least one docking station upon which at least one remote bleed module can be moved to and docked when not connected to a brake bleeder. A drain in the container is actuable when the module is docked at the docking station. A vacuum pump of the central unit removes brake fluid from and provides an initial vacuum charge to the container of the module docked on the central unit. The central unit includes a container for receiving brake fluid removed from the module docked on a docking station of the central unit. 
     The remote bleed modules each include a power source for operating the means responsive to the wirelessly transmitted signals from the central unit. In the example embodiment, the power source is rechargeable and the central unit includes means for recharging the power source when the module is docked at a docking station of the central unit. The fluid passage of the remote bleed module in the disclosed embodiment includes a hose and an adapter to connect to a brake bleeder of an automotive vehicle. The remote bleed module further includes means responsive to the wirelessly transmitted signals from the central unit for alerting an operator to close a brake bleeder connected to the fluid passage of the module. 
     The central unit of the automotive service equipment includes a container for new brake fluid in addition to the aforementioned container for receiving used brake fluid, hoses and adapters for emptying and filling master cylinders, a pressure pump and at least one controlling sensor and a vacuum pump for respectively supplying and pressurizing new brake fluid from the new brake fluid container to master cylinders, and emptying used brake fluid from master cylinders to the used brake fluid container. 
     An improved method for exchanging brake fluid in an automobile in accordance with the invention, using an automotive service equipment of the invention having a central unit with a controller for operating equipment and at least one automatic mode of operation, comprises emptying used brake fluid from the master cylinder of the vehicle, filling the master cylinder with new brake fluid, pressurizing the master cylinder, bleeding brake fluid from brake bleeders of the vehicle and replenishing the new fluid in the master cylinder as necessary, wherein the brake fluid bled from the brake bleeders is stored, for later removal from, in containers of remote bleed modules connected to respective ones of the brake bleeders. 
     The method and automotive service equipment of the invention advantageously avoid the use of hoses for returning the brake fluid to the central unit thus reducing the problem of storage and handling of such hoses and spillage of residual fluid left in the hoses. These and other features and advantages of the invention will be more apparent from the following detailed description taken with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1A  is a perspective view, from the right front and above, of a central unit of an automotive service equipment for brake fluid exchange according to a preferred embodiment of the invention, with three remote bleed modules of the equipment docked at docking stations on the central unit, the left module being sectioned at I-I to show a brake fluid container and drain in the module, with the cabinet of the unit in front and on the right being omitted to show internal components of the unit; 
         FIG. 1B  is a perspective view, from the right front and above, of a remote bleed module which has been removed from one of the docking stations on the central unit of  FIG. 1A ; 
         FIGS. 2A ,  2 B,  2 C,  2 D and  2 E are respectively front, right, back, top and bottom side views of a remote bleed module of the brake bleed equipment of  FIGS. 1A and 1B ; 
         FIG. 3  is a schematic diagram of the automotive service equipment of  FIGS. 1A-FIG .  2 E connected to the brake bleeders of the vehicle to be serviced, the diagram showing the fluid circuits and components of the equipment for brake fluid exchange in the vehicle; 
         FIG. 4  is a schematic drawing of a remote bleed module of the automotive service equipment of  FIGS. 1A-3  showing a docking station of the central unit to which the module can be docked; 
         FIG. 5  is a schematic electrical diagram of the central unit and a remote bleed module of the automotive service equipment of the example embodiment of  FIGS. 1A-4  together with a TechAlert portable communication module of the type disclosed in commonly owned U.S. patent application Ser. No. 11/797,165, now U.S. Pat. No. 7,778,751 issued Aug. 17, 2010, and Ser. No. 11/797,193, now U.S. Pat. No. 7,975,731 issued Jul. 12, 2011, the disclosures of which are incorporated herein by reference. 
         FIG. 6  is a top view of the control panel of the central unit of the automotive service equipment of  FIGS. 1A-5 . 
         FIGS. 7A and 7B  are respective portions of a flow diagram of an automatic mode of operation of the automotive service equipment of the example embodiment of  FIGS. 1A-6  showing operator inputs and displays by the equipment to the operator. 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to the drawings, an automotive service equipment for brake fluid exchange according to the invention comprises four remote bleed modules  1 , refer to  FIGS. 1A to 4 , and a central unit  2  with controlling electronics  17  for operating the equipment in at least one automatic mode of operation for bleeding the brakes of an automotive vehicle. Each module  1  is controlled remotely by the central unit through radio frequency or similar wireless technology in the controlling electronics  17 , see the wireless communication represented by W 1  in  FIG. 5 . 
     Each of the remote bleed modules  1  has a sealed container  3 ,  FIG. 4 , to hold a vacuum charge and waste fluid. A hose  4  and appropriate adapter  5  to connect the module to the brake bleeder,  61  in  FIG. 3 , on an automotive vehicle being serviced provide a fluid passage connecting the module to the brake bleeder and convey brake fluid from the brake bleeder during brake fluid exchange. A solenoid operated valve  6  or other normally closed valve is provided between the brake bleeder adapter/hose and the container  3  for opening and closing the fluid passage between the brake bleeder of the vehicle and the container. A printed circuit board  7  of the module has an antenna to receive wirelessly transmitted signals W 1 ,  FIG. 5 , from the central unit, and has signal processing circuitry to control the operation of the valve  6  and provide necessary information, i.e. visual indication as required via light emitting diodes  8  to the technician during service as explained below. The remote bleed modules  1  further include a drain feature, a check valve  9  in the example embodiment, see  FIG. 4 , that is activated through mechanical means or vacuum when the module is docked with the central unit as described hereinafter. 
     The remote bleed modules further include a battery, super capacitor or other means of power  10 ,  FIGS. 1B and 5 , and/or a charging system to provide the necessary power for operation of the printed circuit board, valve and light emitting diodes of the undocked modules. Electrical contacts  11   b ,  FIG. 4 , of the modules are automatically engaged with electrical contacts  11   a  when the module is docked with the central unit for recharging the power source  10 . As shown in  FIG. 2C , the back of the modules are provided with a magnetic attachment  12  for fixing to steel lifts, etc., and a retractable hook  13  for hanging the modules from the suspension of a vehicle being serviced, or other means. These devices enable the modules to be located near respective ones of the individual brake bleeders  61  of the vehicle as depicted in  FIG. 3 . The cabinet for the modules has a handle and/or overall shape  14  conducive to single-hand maneuvering by the technician, an integrated hose storage  15  for the hose  4 , and docking alignment elements  16  which facilitate docking of the modules with the central unit. 
     The remote bleed modules are adapted to have their sealed containers  3  initially vacuum charged while the modules are docked with the central unit at docking stations  20  thereof,  FIGS. 1A and 4 . The electrical contacts  11   b  (only one is visible in  FIG. 4 ) meet and make electrical connection with the two mating electrical contacts  11   a  as the module is inserted vertically into the port at the docking station. Electrical power from the central unit is thereby available to charge the internal power source  10  of the module. 
     The module has a male fitting  21   b  which mates with the female fitting  21   a  in the docking station as the module is inserted vertically into the docking station. A tight seal between the fittings is accomplished by an o-ring  21   c . The check valve  9  seals fitting  21   b  when the module is not docked. When the module is docked, the check valve opens fitting  21   b.    
     The module  1  is in the form of the sealed container  3  as shown most clearly in  FIG. 4 . Connected to the container is the hose  4  with appropriate adapter  5  to connect the module to a brake bleeder. The solenoid valve  6  is connected in-line with hose  4 . When the module is docked, the check valve  9  opens whereby a vacuum pump  19 ,  FIGS. 1A ,  3 ,  4  and  5 , in the central unit will draw a vacuum on container  3 . Used brake fluid which may be in the container  3  will initially be extracted by this vacuum and deposited in a waste tank or container  23  in the central unit. As the pump continues to run, a vacuum will be drawn on container  3  thereby charging the container of the module for drawing brake fluid from a brake bleeder. Check valve  9  closes as the module is undocked thereby maintaining the vacuum drawn by pump  19  on the container  3 . 
     Connection of the adapter  5  to a brake bleeder  61  of a vehicle and activation of the solenoid valve  6  will apply the vacuum in the container  3  to the brake bleeder to extract brake fluid. The signal to activate the solenoid valve  6  is received from the printed circuit board  7  of the module which is controlled wirelessly from the central unit. Simultaneously with applying the vacuum in container  3  to the brake bleeder, positive pressure and fluid replacement is applied to the brake system master cylinder/reservoir  26 ,  FIG. 3 . In use, once the appropriate amount of fluid has been flushed through the brake system of the vehicle, the central unit transmits a signal for the valve of the module to close, and then signals the next module to open its valve. The process continues until all four module-brake bleeder combinations have been completed. 
     The central unit then alerts the operator to close the bleeders and disconnect the modules and wirelessly signals the appropriate module to flash the light emitting diodes  8  thereon. According to the preferred sequence for closing, the valve  6  on the module with flashing diodes again opens, and a slight positive pressure is applied to the master cylinder by the central unit to prevent any trapped air as the technician closes the bleeder connected to the module. Once the bleeder is closed by the technician, and the central unit detects no flow by flow meter  28 ,  FIG. 3 , the central unit allows the current module to drain the fluid from the hose for a few seconds, then closes the valve of the module. It then sends a signal to the next module and the process is repeated until all bleeders are closed. The hoses and adapters are then detached by the technician at each of the bleeders, and the modules are returned to the central unit for docking. Once docked, draining of the waste fluid and recharging of the module power sources and vacuum charging of the module containers is performed. 
     The controlling electronics  17  of the central unit  2  shown in  FIG. 5  preferably include a digital electronic controller for the operation of the equipment when servicing a vehicle according to the automatic mode of operation illustrated in  FIGS. 7A and 7B  and described hereinafter. Electrical outputs from the controller control the equipment based on logic software of a programmed processor such as a microprocessor of the controller. 
     Well known power/ground connections to ICs and other components may not be shown within the Figs. for simplicity of illustration and discussion, and so as not to obscure the invention. Arrangements may be shown in block diagram form in order to avoid obscuring the invention, and signals (e.g., wireless signals) may be shown in simplicit line form, and also in view of the fact that specifics with respect to implementation of such block diagram and signal arrangements are highly dependent upon the platform within which the present invention is to be implemented, i.e., such specifics should be well within the purview of one skilled in the art. In other instances, detailed descriptions of well-known methods and components are omitted so as not to obscure the description of the invention with unnecessary/excessive detail. Where specific details (e.g., circuits, flow charts) are set forth in order to describe the example embodiment of the invention, it should be apparent to one skilled in the art that the invention can be practiced without, or with variation of, these specific details. Finally it should be apparent that differing combinations of hard-wired circuitry and software instructions can be used to implement embodiments of the present invention, i.e., the present invention is not limited to any specific combination of hardware and software. 
     The controlling electronics  17  of the central unit further include an electronic circuit with wireless communication ability. This would include a wireless transmitter and a wireless receiver coupled to a suitable antenna or other transmission medium coupler as will be readily understood by the skilled artisan. Similar components are provided in the modules. The transmitters and receivers may be either radio frequency (RF) or infrared (IR) devices, but they are of the same type. Signals wirelessly communicated by the central unit to the modules include (but are not limited to) signals to open and close the valves  6  for bleeding fluid from the brake bleeders connected to the modules and signals for turning the light emitting diodes on and off to indicate the sequence for closing the bleeders at the end of a brake fluid exchange. 
     The central unit  2  as shown in  FIGS. 1A ,  3  and  5  has a pump  18  and controlling sensors including pressure switch  30  for filling and applying pressure to the master cylinder/reservoir  26  in the vehicle being serviced. The vacuum pump  19  of the central unit is for emptying the master cylinder in addition to initially charging the sealed containers of the modules and removing waste fluid from the containers of the modules when docked at docking stations  20  as noted above. New fluid is supplied from a tank/container  22  of the central unit while the waste fluid tank/container  23  receives the waste fluid removed from the modules and the master cylinder. Hose  24  and various adapters are used for draining/filling master cylinders  26 . The central unit is housed within an integrated cabinet/enclosure  25  on wheels for portability. 
     The basic functionality of the central unit  2  encompasses providing a vacuum charge to the individual docked modules  1  upon service initialization. An interface to the technician of the central unit is shown in detail in  FIG. 6 . The interface permits the technician to specify fluid exchange amount and the bleeder sequence in a brake fluid exchange for a vehicle, and provides process status and/or action required indications to the technician as discussed in more detail below in connection with  FIGS. 7A and 7B . The central unit serves to connect to the master cylinder/reservoir  26  of the vehicle being serviced to remove used fluid, refill with new fluid, apply pressure and replenish new fluid as necessary. Once service commences, the central unit monitors and controls the overall process and communicates with each module  1 . Once fluid replacement is complete, the central unit alerts the technician via audible and/or visual alert and/or the aforementioned TechAlert remote module  46 ,  FIG. 5 , that the process is complete and that the bleeders need to be closed. Once the technician activates the “close bleeder” sequence, the central unit applies pressure to the master cylinder and sequentially sends signals to each module to activate “attention required” light emitting diodes  8  and open the module&#39;s valve  6 . As described above, once a technician closes the bleeder at the module and the central unit senses no flow, it activates the next module for the bleeder to be closed. When the modules are returned to their docking position on the central unit at service completion, the central unit provides draining capabilities for the waste fluid in containers  3  and recharging of the module power source  10 , e.g., batteries. The central unit includes the charging capability/circuitry for recharging the power sources of the modules. 
     The method for exchanging brake fluid in an automotive vehicle using the automotive service equipment of the invention is illustrated in  FIG. 3 , which shows the component configuration of the central unit and the four remote bleed modules  1  connected to the brake bleeders  61  of a vehicle brake system  60 . As noted above, the sealed container  3  of each module would have been drawn into a vacuum while docked on the central unit docking stations  20 . The printed circuit board/controller  7  in each module is in wireless communication with the central unit controller. Signals are transmitted from the central unit controller to open and close solenoid valve  6 . When solenoid valve  6  is open, the vacuum in the module container will cause brake fluid to be drawn from the brake caliber cylinder via a brake bleeder at the four brakes/wheels of the vehicle. A filter  34  in the hose traps any particulates which may be in the used brake fluid. Extracted brake fluid is stored in the container  3  of the module until the module is docked on the central unit. 
     Hose  36  of the central unit as shown in  FIG. 3  is used to extract as much used fluid from the master cylinder/reservoir  26  of the vehicle brake system  60  as possible. Then wand  37  is connected to hose  24  and used to refill the reservoir with new fluid. 
     Hose  24  is then connected to the brake fluid reservoir using a special adapter. New brake fluid from container  22  is pumped by the pump  18  through the hose  24  to the brake fluid reservoir  26  of the brake system. A filter  27  traps any particulate which may be in the new fluid. The flow meter  28  measures fluid flow and gives electrical signals to the central unit controller. The amount of fluid flow used is in the system logic as selected by the technician during initialization as explained below with reference to  FIGS. 7A and 7B . A fixed orifice  29  dampens any fluid pulses caused by pump  18 . The pressure switch  30  controls the maximum fluid pressure at the brake system reservoir  26 . Pressure gauge  31 ,  FIGS. 3 and 6 , is for visual indication of the fluid pressure and the system. The waste fluid container  23  has a level switch  32  to prevent overfilling the container with used fluid. The new fluid container  22  has a level switch  33  to stop pump  18  when the level of new fluid is low, preventing the pumping of air into the braking system. A solenoid valve  35  is energized to allow the pump  18  to pump any unused brake fluid from container  22  to container  23 . This is an optional choice for the technician if the new fluid will not be used in the near future. Brake fluid absorbs moisture exposed to air for an extended period of time. 
     For commencing the automatic mode of operation of the automotive service equipment, the technician programs the central unit by selecting the sequence (specified by the vehicle manufacturer) in which fluid will be extracted from each of the brakes of the vehicle. He also selects whether to empty any unused new fluid into the waste fluid container at the end of the fluid exchange procedure. The central unit controller then pumps new fluid into the master cylinder/reservoir of the vehicle brake system and sequentially extracts used fluid from each of the four brakes in the sequential order programmed. The amount of new fluid pumped to each brake is determined by the central unit controller based on the amount of fluid sensed by flow meter  28 . 
     The total amount of new fluid used during the entire exchange of all four brakes is programmed by the technician. Three total amounts ( 32 ,  48  and  64  ounces) can be selected in the example embodiment. The central unit controller calculates and then controls the amount of fluid which is exchanged at each of the brakes. 
     As shown in  FIG. 5 , the automotive service equipment of the invention can optionally be used with the TechAlert remote module  46  to alert the operator by way of the portable communication module  46  of the status of the equipment operation, e.g. operation complete or operator attention required, for example. For this purpose, the controller of the central unit has a socket  41  and mating jumper plug  40 . Insertion of the plug into the socket initiates communication at receptacle  42 . A stationary module  45  of the TechAlert with electrical cable  44  and plug  43  is plugged into the receptacle  42 . The stationary module  45  includes a wireless transmitter and a wireless receiver coupled to a suitable antenna or other transmission medium coupler for communicating signals wirelessly to the remote module  46  as described in more detail in the aforementioned commonly owned applications incorporated herein by reference. The wireless communication between the remote module  46  and the central unit is shown at W 2  in  FIG. 5 . 
     The sequence of steps performed by the equipment for fluid exchange, with operator inputs in response to prompts by the equipment display  50 , are set forth in  FIGS. 7A and 7B . The push buttons  53 ,  57 ,  58  and  59  permit the operator to set the sequence of brake fluid exchange in a vehicle, where LF stands for left front, RF for right front, LR for left rear and RR for right rear brakes to be bled. The several push buttons  51 ,  52 ,  54 ,  55  and  56  are for operator input to respectively empty the master cylinder, fill the master cylinder, continue, flush and pause the operation of the equipment. The flow chart of  FIGS. 7A and 7B  describes in more detail the operation of the equipment and operator input/control where necessary for brake fluid exchange in accordance with a preferred embodiment of the invention. 
     Where we have shown and described one preferred embodiment of the present invention, it is understood that the invention is not limited thereto but is subject in numerous modifications and variations which will be apparent to the skilled artisan. As one variation, the automotive service equipment could employ fewer brake bleed modules than the four of the embodiment, where necessarily a module would have to be used with more than one brake bleeder of a vehicle being serviced by connecting and disconnecting the module in sequence with the brake bleeders of a vehicle. A further variation could employ a brake bleed module with two independently controlled solenoids, each connected to a hose. This dual brake bleed module could then be located mid-way between the rear or front brakes with one hose connected to the right side brake and the other hose connected to the left side brake. Thus, the above descriptions of example embodiments are not intended to be limiting. All such modifications coming within the scope of the appended claims are intended to be included therein.