Abstract:
The present invention provides a new braking system for a first vehicle towing a second vehicle on its own four wheels. The system exhibits a process by which the towing vehicle&#39;s brake system send an electronic relay to the towed vehicle&#39;s brake system making the brake depress at the proper rate of deceleration.

Description:
REFERENCE TO EARLIER APPLICATION 
     This Application is a CIP Application of U.S. patent application Ser. No. 09/099,217, filed Jun. 18, 1998, now abandoned by Ronald Chesnut entitled UNIFIED BRAKE SYSTEM FOR TOWED AND TOWING VEHICLES from which it claims priority. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to controlled braking of vehicles. More particularly, the present invention provides a system for operating the brakes of a towed second vehicle in response to the braking of a first vehicle. 
     2. Description of the Prior Art 
     When operating larger road vehicles, such as recreational vehicles (RVs), motor homes, trucks, and the like, it is often desirous to also have a smaller vehicle available. Typically, this is accomplished by either having two drivers operating the vehicles independently, or by trailering the smaller vehicle to the larger vehicle. Operating two vehicles independently has several disadvantages, including increased fuel consumption and driving labor, as well as the possibility of the vehicles being separated in the course of travel. Trailering requires yet a third vehicle upon which the smaller vehicle is carried, adding expense as well as requiring storage/parking accommodations. 
     A third option is to tow the smaller vehicle on its own four wheels. Heretofore, this has been typically accomplished by hitching the smaller vehicle to the larger vehicle and placing the smaller vehicle in a neutral gear. While this may seem a reasonable solution, it poses some serious problems. Among the most serious, is the complete reliance on the towing vehicle for braking the greatly increased mass of the towing vehicle/towed vehicle combination. This increased mass disadvantageously impacts both the stopping distances and time, as well as creating undue wear on the brakes of the larger vehicle. Further, the mechanical connection between the larger vehicle and the smaller vehicle is unduly stressed. 
     Also, ABS systems on modern vehicles have a contamination problem when being towed. The ABS systems are rendered inoperative when their fluid level is altered by less than one ounce. Improper handling of these ABS brake systems can cause faults in their computer programs, and the operation of the brake and traction systems. 
     The prior art has sought to remedy this problem. In one such remedy, each time a vehicle is to be towed, a device is inserted into that vehicle to operate its braking system, or to substitute for its braking system. The device is then connected to the braking system of the towing vehicle through hydraulic, high pressure air, or vacuum lines. Though more effective than having no contribution to overall braking from the towed vehicle, these remedies rarely approach the ideal, in which no additional load is placed on the towing vehicle&#39;s brakes. Further, in order to independently operate the towed vehicle, the installed braking device must be removed, as well as the hydraulic, air or vacuum lines. The inconvenience of repeatedly installing and removing braking devices and cumbersome lines has limited the acceptance of these types of prior art systems. Additionally, the required connection and disconnection may result in air or other contamination of the closed brake systems, rendering them inoperative. 
     None of the prior art, taken either singly or in combination, is seen to describe the instant invention as claimed. 
     SUMMARY OF THE INVENTION 
     The present invention provides a new braking system for a first vehicle towing a second vehicle on its own four wheels. This is accomplished without cumbersome hydraulic, pneumatic, and/or vacuum lines connecting the braking apparatus of the first vehicle to that of the second vehicle. The invention operates independent of existing hydraulic or air brake systems using only electrical impulses from the brake system of the towing vehicle to activate a controller in that same vehicle which then activates the electronic actuator in the second vehicle (Towed Vehicle) which transfers its electronic energy to mechanical energy activating the hydraulic power brake system of the Towed Vehicle. The retrofitting of either brake system will not render either system inoperative. Further, the present invention provides modifications to the second vehicle&#39;s existing braking system which need not be removed, as the modifications do not interfere with normal independent operation of the second vehicle. 
     The braking system includes the existing braking apparatus on the first vehicle and the existing braking apparatus of the second vehicle with modifications as noted. These modifications include an electrically powered vacuum pump assembly for providing vacuum to an existing vacuum booster of the second vehicle; a one way check valve installed between the existing vacuum booster and engine of the second vehicle; an electrically powered brake actuator assembly installed in the second vehicle; and a mechanical actuator cable connecting the brake actuator assembly to the second vehicle&#39;s brake pedal. 
     Electrical power to the vacuum pump assembly and the battery of the second vehicle is provided through a first power line. Variable power to the actuator assembly is provided through the second power line. The first power line is connected to a power source in the first vehicle which will provide constant power from its battery and alternator when in operation. The second power line is connected to an adjustable controller in the first vehicle which operates electrically by sensing the brake lights have been activated by application of its brake light switch. The first and second power lines as well as the brake actuator line run through an umbilical between the first and second vehicles. The umbilical may be provided with socket and plug connectors at either, both, or anywhere along the umbilical, for connecting/disconnecting electrical power and communication between the first and second vehicle. 
     The electronic brake control located in the first vehicle is inertia activated utilizing integrated circuitry for safe, smooth stops. It has an ergonomic design which allows contour installation on the dash for maximum visibility and comfortable reach. It features an easy to access manual override slide lever, an LED power level display that shows the amount of current delivered to the second vehicle. Dual colored leveling system makes leveling easier, and a gain control adjusts the amount of current to the actuator. The present invention meets NHTSA regulations, and is compatible with virtually every 12 volt battery, or negative ground tow vehicle of foreign or domestic origin. 
     The first vehicle and second vehicle are mechanically connected by any convenient method, such as by a standard hitch assembly. So long as the mechanical connection is secure, the umbilical will be substantially safe from accidental disconnection. To provide braking in the second vehicle in the unlikely event that accidental disconnection in the umbilical does occur, an emergency brake circuit may be provided in the second vehicle along with an activating lanyard. 
     The emergency brake circuit is connected to the second vehicle&#39;s battery which provides input to an emergency brake switch of the circuit. The brake switch has outputs to both the brake actuator assembly and the vacuum pump assembly of the second vehicle. One end of the lanyard is attached to the switch, while the other is attached to the chassis of the first vehicle. The switch, normally in the open position, is closed when pulled by the connected lanyard, as would occur if the second vehicle should break away from the first. Thus closed, the emergency brake circuit would provide power from the second vehicle&#39;s battery to the brake actuator assembly and the vacuum pump assembly, and the second vehicle would brake. 
     Accordingly, the present invention provides an improved braking system that optimally and adjustably utilizes the braking apparatus of both a towing first vehicle and a towed second vehicle. The present invention also provides the operator of the towing vehicle the ability to adjust during driving, the brake required on the second vehicle, based on road conditions, traffic, weather, terrain, or any other variable the operator may encounter while traveling. Additionally, the present invention provides a kit for retrofitting existing braking apparatus of a first vehicle and a second vehicle to produce the improved braking system. 
     The present invention provides a system that does not require removal of any installed device within either the first or second vehicle to operate the vehicles independently. The present invention also provides emergency braking in the second vehicle should it accidentally break away from first vehicle. The present invention additionally provides improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes. 
     The present invention provides an improved auxiliary brake system independent of variables in either the first vehicle, or second vehicles brake systems. Also, the present invention provides an improved brake system for vehicles pulling other vehicles on all four wheels, that is relative to pressure and not variable travel of brake pedals. 
     The present invention eliminates all variables of brake performance in towing situations by sensing the actual braking forces of the first vehicle and reproducing the same braking force in the second vehicle. Also, the present invention provides an improved auxiliary brake system that utilizes the power brakes of the second vehicle. Additionally, the present invention provides an improved auxiliary brake system which does not invade the existing brake systems of the first or second vehicles as not to affect the normal operation of their ABS systems. 
     The present invention provides a system that is hidden with all components located under the seat, under the dash, under the carpets or in the engine compartment as not to be visible. Also, the present invention provid an auxiliary braking system that is not vehicle manufacturer dependant, or dependant on a particular type of braking system (i.e. ABS). The present invention additionally provides an improved brake system for a first vehicle that tows a second vehicle that utilizes components available to the Recreational vehicle industry. 
     The present invention provides an improved auxiliary brake system which provides a variable braking force on the second vehicle that is relative to the braking utilized by the first vehicle. Also the present invention does not require frequent adjustments for proper operation. Additionally the present invention provides a manual override to apply the brakes in the second vehicle without applying the brakes in the first vehicle. 
     The present invention provides a visual indication to the operator of the first vehicle the amount of braking force used in both vehicles. Also the present invention provides a visual indication as to the continuity of the system and its operation. 
     These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view showing a first vehicle towing a second vehicle with the present braking system in place. This view is not relative to operation. Only the controller located in the towing vehicle will be required to be leveled. The units retrofitting the second vehicle can be located upside down or side ways without effecting operation. 
     FIG. 2 is a block diagram of a braking system according to the present invention. 
     FIG. 3 is a detail cutaway top view showing a vacuum pump assembly according to a preferred embodiment of the present invention. 
     FIG. 4 is a detail cutaway side view of a brake actuator according to a preferred embodiment of the present invention. 
     FIG. 5 is a side view of a brake pedal of the second vehicle, showing connections to a brake actuator cable. 
     FIG. 6 shows the entire wiring and set up system for both vehicles, as well as how each component attaches to the next as fully assembled. 
     Like reference characters designate the same or similar parts throughout the drawings. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIG. 1, the present invention provides a braking system  110 , for a first vehicle  100 , towing a second vehicle  200  on its own four wheels. A mechanical connection, hitch  300 , removably and securely connects the first  100  and second  200  vehicles. An electrical umbilical connection  400 , removably places the first  100  and second  200  vehicles in electrical communication, and includes a plurality of wires. By operating brakes  190  on the first vehicle, an electrical signal is sent to the first vehicle&#39;s brake lights  105 . Substantially simultaneously, an electrical signal is sent from the first vehicle through the umbilical  400  to the second vehicle, activating the second vehicle&#39;s brakes and braking lights  205 . A safety lanyard  500 , connects the chassis of the first vehicle  100  to an emergency brake switch  222  of the second vehicle  200 . No cumbersome hydraulic, pneumatic, or vacuum lines are required. 
     Referring to FIG. 2, the present braking system includes the existing mechanicavhydraulic braking apparatus of the first vehicle  110  and the existing mechanicavhydraulic apparatus of the second vehicle  210 . The present braking system has not modified either existing brake system. Modifications to vehicle  200  are to tee into the vacuum line from the engine  260  to the brake booster  240  also to insert a one way valve  250  between the tee and the engine  260 . Additional one way valve  250  is installed on the added vacuum line of vacuum pump  230 . This one way valve  250  allows the vacuum pump assembly  230  to supply vacuum only to the brake booster  240  when the engine  260  is not running. When the engine  260  is running in normal operation mode, the engine  260  will supply the vacuum. In FIG. 2, dotted lines indicate mechanical connections to blocks, single solid lines indicate electrical connections between blocks, and double solid lines indicate vacuum connections between blocks. An electrically powered brake actuator assembly  270  is shown; and a mechanical brake actuator cable  272  connects the brake actuator assembly  270  to the second vehicle&#39;s brake pedal  280 , for activating the second vehicles brakes  290 . 
     Electrical power to the vacuum pump assembly  230  is provided through a first power line  440 . Power to the brake actuator assembly  270  is provided through a second power line  470 . These power lines are connected to the electric powersource in the first vehicle  100 , battery  120 . An emergency brake switch  222 , normally open, is connected on the input end to the second vehicle&#39;s battery  220 . The brake switch  222  is connected electrically to both the brake actuator assembly  270  and the vacuum pump assembly  230 . Lanyard  500  is mechanically attached to the switch  222 . 
     An adjustable br controller  420  receives its signal input from the brake light circuit  105  of the first vehicle  100 . This controller  420  can provide variable current to the actuator assembly  270 . A conventional feature controller  420  available in the recreational vehicle industry, may be advantageously used. This controller  420  produces a variable current relayed through the second power line  470  to the actuator assembly  270  when the brake lights  105  of the vehicle  100  are activated. This current is proportional to the amount of deceleration detected by the controller  420 . 
     Referring to FIG. 3, the vacuum pump assembly  230  preferably includes a vacuum pump  232 ; a vacuum diaphragm choke dash pot  234 ; a vacuum adjustment spring  236  and a vacuum adjustment knob  238 . By this arrangement, vacuum produced by the assembly  230  may be adjusted to produce 0 to 25 inches of vacuum. This is subsequently adjusted to an operating range of about 15 to about 20 inches of vacuum to the vacuum booster  240 . A compressor of conventional design may be modified to provide the vacuum pump assembly  230 . 
     Referring to FIG. 4, the brake actuator assembly  270  preferably includes a mounted solenoid  274  connected to one end of a pull lever  276  with the other end furthest from the pivot point to the brake actuator cable  272 . The travel is then multiplied by the lever  276  so that one inch of travel of the solenoid  274  will relate to four inches of travel of brake actuator cable  272 . Moving the brake actuator cable  272  closer or further from the pivot point will decrease or increase the travel to eliminate the variables in the towed vehicle&#39;s  200  brake pedal travel. 
     Turning to FIG. 5 the actuator cable  272  runs from the actuator assembly  270  to the back of brake pedal  280  of the second vehicle  200 , where it is securely attached. A preferred arrangement includes guides  273  through which cable  272  may slidably travel. These guides  273  may be secured to various interior surfaces of the second vehicle  200  to prevent lateral displacement of actuator cable  272 , and allows more flexibility in the placement of actuator assembly  270 . 
     Referring to FIG. 6, a complete view of the present unified brake system of towed and towing vehicles is shown. This figure shows all electrical, mechanical and physical components of the present unified brake system for both vehicles  100  and  200 . All components to the upper left are located on vehicle  100 ; all components at lower right are located in towed vehicle  200 . Umbilical  400  connects between vehicle  100  and  200  electrically and contains power relay wires  440  and  470  as defined in FIG.  2 . Lanyard  500  mechanically connects chassis  100  to chassis  200  at its break-away switch  222 . Should the two vehicles become separated, the lanyard will pull out of break-away switch which is normally in the open position and supply operating power from vehicle  200  battery  220  to the vacuum pump  30  and the brake actuator assembly  270  by pulling cable  272  and subsequently pulling down on the brake pedal  280  applying power assisted brakes. Umbilical line  440  supplies charge and operating current to both the vacuum pump  230 , brake actuator assembly  270 , and battery  220  of vehicle  200  from vehicle  100  alternator and battery  120 . A  20  amp circuit breaker  64  is in harness  10  for protection of wiring harness  10 . In vehicle  100 , wire  70 , wire harness  10 , wire  12 , and wire  14  supply operating power from the battery of  120  of vehicle  100  when the key is turned on. Wire  16  is connected to the brake light switch for a signal when the brake lights are activated. Wire  72  contains operating signal and current for wire  470  of umbilical  400  to continue to brake actuator assembly  270 . The brake actuator assembly  270  is mechanically connected through cable  272  which contains a sleeve and inner cable  272 . The cable  272  runs under the carpet to its outer sleeve bracket  42  which securely attaches the sleeve to the floor of vehicle  200 . The inner cable continues through guide  273  which is also secured to the floor directly behind the brake pedal  280 . This inner cable continues on and is securely attached to the pedal  280 . 
     The multiplication of travel as described in FIG. 4 is done by moving the point of attachment to pedal  280  closer or further away from its pivot point. Moving the attachment of cable  272  closer or further from the brake pedal  280  pivot point will compensate for variables in brake pedal  280  travel from rest to applied position and keep the solenoid operation in its limited one and one half inch of travel. Varying the current on solenoid  274 , based on deceleration of inertia sensing controller  420  of vehicle  100 , will reproduce the simultaneous same braking on vehicle  200  non relative to brake pedal travel. Maintaining the vacuum on booster  240  at the optimum level of between 10 to 25 inches of vacuum with vacuum pump assembly  230  when vehicle  200  is in tow will allow power assisted braking. A one way valve  250  is located between the tee and the engine in order to prevent vacuum pump  230  from supplying vacuum to the engine. Another one-way valve is internal to the vacuum pump  232 ; also a one-way valve  250  is located at the booster end of the line from the engine  260  at booster  240 . A 40 amp circuit breaker  68  provides protection for wire harness  10  and its components located in vehicle  200 . Power module  60  contains power amplification from controller  420  along with other associated relays and controls to control the operation of components located in vehicle  200 , including break-away power brake actuator assembly  270 . Brake actuator assembly  270  has a mounting plate, a solenoid  274 , and associated hardware for mounting the outside sleeve of cable  272  at the plate. The inside cable is securely fastened to the solenoid core. The mounting hardware also serves as a stop for the core keeping it within its limited travel. 
     The umbilical electrical connection  400  is linked through circuit breaker  64 , which protects the umbilical electrical connection  400  to the first vehicle  100 . The umbilical electrical connection  400  then continues through that box to the battery  120  of the first vehicle  100 . Attached to the umbilical electrical connection  400  is the wiring harness connector clamp  18  leading to the wiring harness  10  and the second vehicle  200 . Adjacent to the umbilical electrical cord  400  is the safety lanyard  500  attached to the emergency brake switch  222 . The emergency brake switch  222  is connected to the wiring harness  10 . The wiring continues through a conventional fire wall  66  to the power module  60 . 
     The power module  60  is connected to ground wire  14 , the second vehicle&#39;s brake light switch  205 , and through a connector  68  to the electronic solenoid  274 . The electronic solenoid  274  sits on the solenoid plate  54 , and ends at the solenoid stop  52 . The solenoid  274  is held together by means of an Allen set screw  28 , a socket head screw cap  36 , a lock nut  58 , a carriage bolt  56 , and a jam nut  50 . The electronic solenoid  274  is attached by cable assembly  46  to an outer cable stop bracket  42 , and through the bracket  42  around self tapping screw  26  to the flat block pulley  62 . From the self tapping screw  26 , the cable assembly  46  continues through the brake pedal bracket clamp  38  to the brake pedal adjust side  40  intersecting the brake pedal  280 . Shown in the enlarged detail sections of the drawing we see a close up view of the self tapping screw  26 , Allen set screw  28 , hairpin clip  30 , and pulley pin  32 , as attached to the cable assembly  46 . When the solenoid  274  is signaled by the power control module  60  it will pull on cable assembly  46  thus depressing the brake pedal  280 . The amount of current relayed from the power control module  60  to the solenoid  274  determines the amount of pull sent to the cable assembly  46 , and the amount of pressure of the brake pedal  280 . 
     Also shown in enlarged detail are the lock washer  34  and socket head cap screw as attached to the electronic solenoid  274 . The power module  60  is simultaneously attached via a wire harness  10  through the fire wall  66  to the vacuum pump assembly  230 . The vacuum pump assembly  230  is attached via hose  24  to tee fittings  22  which in turn are connected to conventional check valves  20 . 
     It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.