Patent Application
20220055598
The present invention relates to air brake systems for trailers and more particularly to a lock for the supply line coupler of a trailer emergency air brake system.
On the back of a tractor, on the driver side, there are three lines which connect with a trailer. The lines are color coded red, green, and blue. The red line is the air supply line for the trailer's emergency air brake system. The blue line is the air supply line for the trailer's service air brake system. The red and blue lines are connected to the corresponding couplers in the trailer. The green line is the electrical connection between the tractor and trailer. The end of the green line is plugged into a socket on the trailer. These lines are all connected before moving the trailer.
The red air supply line connects the tractor air supply to the trailer. The red air supply line provides air pressure to release the trailer emergency air brake. If the red air supply line breaks, leaks or is disconnected, the trailer emergency air brakes will be automatically engaged, and the trailer cannot be moved. The blue air brake supply line is connected to the trailer service brake system. The driver of the tractor controls the air pressure to engage or release the trailer service air brakes through the blue air brake supply line. The green line is an electrical cable. It supplies electric power for lights, signals and ABS brakes of the trailer.
The emergency air brake supply line has a coupler at the end. The line coupler is connected to a coupler fixed on the trailer to control the trailer emergency air brakes. The line coupler is removably attached to the trailer coupler in a manner which allows the line coupler to rotate relative to the trailer coupler between two different positions.
In one position, the driver can control the operation of the trailer emergency air brakes by regulating the air pressure in the emergency air brake supply line. In the control position, air pressure from the tractor supplied through the emergency air brake supply line coupler causes the trailer emergency air brakes to release, so the trailer can be moved. In the absence of air pressure, the emergency air brakes are automatically engaged, preventing movement of the trailer.
In a second (park) position of the emergency air brake supply line coupler, the trailer emergency air brake supply line can be detached from the trailer emergency air brake supply line coupler. Detaching the trailer emergency air brake supply line from the trailer emergency air brake supply line coupler will vent the trailer emergency air brake system, causing the trailer air brakes to engage. In the park position of the trailer emergency air brake supply line coupler, the trailer emergency air brake system cannot be pressurized, preventing the trailer from being moved. As long as the trailer emergency air brake supply line coupler is in the park position, the driver can disconnect the air supply lines and the electrical cable from the trailer, and the trailer emergency air brakes will remain engaged.
The end of trailer emergency air brake supply coupler is internally threaded. The end of the trailer emergency air brake supply line is externally threaded. Thus, the trailer emergency air brake supply line can be disconnected from the trailer emergency air brake supply line coupler to allow the tractor to be disconnected from the trailer. Disconnecting the emergency air brake supply line coupling from the trailer coupling vents the trailer emergency air brake system, whether the trailer emergency air brake supply line coupler is in the control position or the park position.
Trailers are frequently left loaded with the line coupler in the park position without a tractor and thus without the emergency air brake supply line coupler connected. In that condition, the trailer is venerable to being stolen, even though the trailer emergency air brakes are engaged because the trailer emergency air brake system is vented. However, when the supply line coupler from any tractor is attached to the trailer and the line coupler is moved to the control position, the emergency air brake system of the trailer can be pressurized to release the trailer air brakes. Thus, unauthored individuals can steal the trailer.
In order to avoid unauthorized pressurization of the trailer air brake system to release the emergency the air brakes, a plastic device has been attached to the trailer to prevent the line coupler from being moved to its control position and the system be pressurized. However, these devices are ineffective because they are easily removed, and the trailer stolen.
Further, many trailer thefts occur when a tractor and trailer are stopped in traffic. The thief climbs between the tractor and trailer, moves the line coupler to the park position and disconnects the emergency air brake supply line from the trailer. Often, in this situation, the driver out of fear drives away in the tractor without the trailer to protect themselves and leaves the trailer to be stolen. The thief then moves the line coupler to the control position, pressurizes the trailer emergency air brake system and takes the trailer.
Accordingly, there is a need for a device which will reliably prevent the trailer emergency air brake system from being pressurized to release the trailer emergency air brakes without authorization.
More specifically, there is a need for a device which will prevent a trailer emergency air brake supply coupler from being moved to a position where the trailer emergency air brake system can be pressurized to release the trailer emergency air brake.
The present invention is a lock for the coupler of the supply line of a trailer emergency air brake system. The lock consists of a strong metal frame designed to be attached to the front of a trailer proximate to and surrounding the trailer coupler. A retractable pin intersects the path of movement of the line coupler. When in place on the frame, the pin does not allow the supply line coupler to be moved between the control position, where the supply line provides compressed air as needed to control the trailer emergency air brakes, and a park position, where the trailer emergency air brake system is vented and the trailer emergency air brakes are engaged.
In the control position, the lock prevents theft of the trailer in stopped traffic because as soon as the supply line is removed by a would-be thief, the trailer emergency air brake system is vented, automatically engaging the trailer emergency air brakes preventing movement of the trailer.
When parking the trailer, before the tractor is disconnected from the trailer, the driver removes the pin from the lock frame and moves the trailer emergency air brake supply line coupler to the park position, venting the trailer emergency air brake system, and causing the trailer air brakes to engage. The pin is then replaced on the frame, preventing the trailer emergency air brake supply line coupler from being moved from the park position to the control position. In the park position, the trailer emergency air brake system cannot be pressurized to release the trailer emergency air brakes. The supply line can then be removed from the line coupler and the trailer can be safely left because the air brakes are engaged, and the trailer cannot be moved.
In its preferred embodiment, the present invention is a lock for the emergency air brake supply line coupler of a trailer emergency air brake system including a trailer coupler fixed to the trailer and configured to connect the emergency air brake supply line to the trailer emergency air brakes. The supply line coupler is movable between a control position, where air pressure in the supply line causes the trailer emergency air brakes to release so the trailer can be moved, and a park position where the trailer emergency air brake system is vented to automatically engage the trailer emergency air brakes. The lock includes a metal frame having a rear wall attached to the trailer proximate the trailer coupler. First and second spaced side walls extend from the rear wall on opposite sides of the trailer coupler. A retractable pin extends between the side walls and intersects the path of movement of the supply line coupler preventing movement of the supply line coupler between its control position and its park position.
A lock cylinder, padlock or other locking mechanism is employed to engage the end of pin to prevent the pin from being retracted from the frame.
The rear wall includes an opening through which the trailer coupler extends. The rear wall is formed of first and second spaced members at least partially defining the rear wall opening.
The pin has an enlarged end which is situated proximate one side wall surface. The enlarged head presents the pin from being pulled through an opening in the side wall.
To these and to such other objects that may hereinafter appear, the present invention relates to a lock for a trailer emergency air brake supply line as described in detail in the following specification and recited in the annexed claims, taken together with the accompanying drawings in which
The emergency air brake supply line B provides air pressure to control the emergency air brakes for trailer A. When high air pressure is present in supply line B, the trailer emergency air brakes are released, and the trailer can be moved. In the absence of air pressure in supply line B (the line is vented), the trailer emergency air brakes automatically engage, and the trailer cannot be moved.
The service air brake supply line C provides air pressure to control the service air brakes of trailer A. When high air pressure is present in supply line C, the trailer service air brakes are released, and the trailer can be moved. In the absence of air pressure in the supply line C (the line is vented), the trailer service air brakes automatically engage, and the trailer cannot be moved.
The electric cable D supplies electric power to operate the lights, signals and ABS brakes of the trailer.
The emergency air brake supply line B is connected to the trailer emergency air brake system by mating couplers. Each coupler has a metal connecting part and a handle part. The emergency air brake supply line coupler has a handle part 10 which is connected to supply line B and a metal connecting part 12 configured to engage the metal engaging part 14 of the emergency air brake system coupler 16 fixed to trailer A.
The service air brake supply line C is connected to the trailer service air brake system by mating couplers. Each coupler has a metal connecting part and a handle part. The service air brake supply line coupler has a handle part 18 which is connected to supply line C and a metal connecting part 20 configured to engage the metal engaging part of the service air brake system coupler fixed to trailer A.
The connections are color coded so they can be easily distinguished. The emergency air brake supply line coupler handle part 10 is red. The service air brake supply line coupler handle part 18 is blue. The electrical cable is green.
The end of each supply line is externally threaded. Each coupler has an in the internally threaded handle part end configured to receive the supply line end. This allows the supply lines to be disconnected from their respective supply line couplers.
Each supply line coupler can be moved relative to its respective trailer air brake system coupler between control and park positions.
Referring now to
Extending between side walls 24 and 26 is a strong metal pin 28 which, when received on the frame, intersects the path of movement of the emergency air brake supply line coupler handle part 10, such that the emergency air brake supply line coupler handle part cannot be moved between the control position and the park position.
Pin 28 has an enlarged head 30 on one end which limits how far the pin can be moved through an opening in side wall 26. The other end of pin 18 is received in a lock cylinder 32 which is fixed to side wall 24. The external portion of lock cylinder 32 has an entrance opening 34 for a key which causes the lock cylinder to engage or release the pin end.
Referring again to
With the pin removed, the emergency air brake supply line coupler can be moved to the park position. With the coupler in the park position, the pin can be inserted back into the frame. The pin then prevents the coupler from being moved to the control position. In the park position, the trailer emergency air brake system is vented and cannot be pressurized to release the trailer emergency air brakes. In the park position, the emergency air brake supply line coupler can be disconnected from the trailer.
Pin 18 has an end 36 of reduced diameter with a circumferential recess. Pin end 36 is configured to be received within and engaged by lock cylinder 32. The lock cylinder prevents the removal of the pin from the frame without a key. Thus, movement of the emergency air brake supply line coupler by unauthorized individuals is avoided.
It will now be understood that, in the control position, the lock prevents theft of the trailer in stopped traffic because as soon as the supply line is removed by a would-be thief, the trailer emergency air brake system is vented, automatically engaging the trailer emergency air brakes preventing movement of the trailer.
When parking the trailer, before the tractor is disconnected from the trailer, the driver unlocks and removes pin 18 from frame E and moves the trailer emergency air brake supply line coupler to the park position, venting the trailer emergency air brake system, and causing the trailer air brakes to engage. The pin is then replaced and locked on the frame, preventing the trailer emergency air brake supply line coupler from being moved from the park position to the control position. In the park position, the trailer emergency air brake system cannot be pressurized to release the trailer emergency air brakes. The supply line can then be removed from the line coupler and the trailer can be safely left because the air brakes are engaged, and the trailer cannot be moved.
While only a limited number of preferred embodiments of the present invention have been disclosed for purposes of illustration, it is obvious that many modifications and variations could be made thereto. It is intended to cover all of those modifications and variations which fall within the scope of the present invention, as defined by the following claims.
