Illumination – Self powered lamp – Generator power source
Reexamination Certificate
2000-12-14
2002-11-05
Husar, Stephen (Department: 2875)
Illumination
Self powered lamp
Generator power source
C362S478000, C362S193000, C362S500000, C310S100000
Reexamination Certificate
active
06474832
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to railcar-mounted warning lights and more particularly to status-indicating assemblies mounted on the wheels of train cars that utilize the rotation of the axle to generate power.
BACKGROUND OF THE INVENTION
It is known that the lack of lighting on railcars presents a serious safety issue for motorists, especially at uncontrolled rail crossings. The sides of train cars are typically unlit. At night, the train locomotive headlights quickly pass the crossing and drivers of vehicles sometimes do not see the railcars and run into the unlit side of the train, resulting in serious injury or death.
The high cost of monitoring and controlling all rail crossings is prohibitive. It would therefore be advantageous to provide warning lights directly on the railcars. However, lack of electrical service onboard the majority of railcars has presented the greatest difficulty with respect to the installation of warning lights. Gas generators and conventional alternators have been tried, however, bulky installation and safety hazards with respect to sparks from carbon brushes have restricted their use.
U.S. Pat. No. 5,828,135 issued to Barrett is known which describes a wheel-mounted generator used to power electrical braking systems, car lighting and other functions requiring electricity. The generator produces electricity through the relative motion of permanent magnets adjacent to stationary coils positioned about the railcar axle. Barrett has addressed the issue of securing coils about the axle, however, it necessitates complex construction and it's power producing capability far exceeds that to power a warning light system and it adds significantly to the cost of installation, considering the large number of railcars.
Boyer, in U.S. Pat. No. 4,539,497 discloses a wheel-mounted generator within a toroidal housing for mounting around a vehicle axle. The generator is suitable to provide power to associated signal transmitters responsive to such apparatus as tire pressure sensors on multi-wheel vehicles. A pendulum is journaled about the housing passage through which the axle passes. A ring gear is mounted to the housing and engages a pinion gear on the generator armature shaft when the housing rotates. The ratio of the gears drives the generator at a rate greater than the wheel rotation rate. A magnet is attached to and rotates with the housing. The armature of the generator remains relatively stationary with respect to the magnet due to the resistance of the gears rather than the weight of the pendulum. Gear-driven generators require significant servicing to ensure replacement of worn gears for continued operation.
In U.S. Pat. No. 5,584,561 to Lahos, utilizes a simple combination of two separate components; a magnet attached to the rotating wheel of a bicycle and a solenoid attached to the fixed bicycle frame. The solenoid's coil is electrically connected to a series of diodes. In operation, the wheel-mounted magnet is repeatedly driven past the solenoid during rotation of the wheel. The magnet's magnetic field generates an alternating current in the solenoid's coil which is fed to a diode bridge where the signal is rectified and fed to an electronic signaling device that produces electronic pulses to electroluminescent diodes. Electrical storage devices are provided for ensuring continued lighting even if the wheel is not rotating.
In the Lahos application, the bicycle has a convenient frame and wheel providing consistent spacing, a generally non-hazardous environment and a positive relative rotation for periodic induction of an electrical current.
In the context of a railcar, the fixed frame portion is not necessarily located in convenient proximity to the rotating components and the potentially damaging heavy industrial environment includes impact hazards and a prevalence of spalled metal from rails and other metal debris. In such industrial settings, an exposed magnet quickly accumulates metal debris which can render it unable to produce sufficient magnetic field to induce an electrical current in a passing solenoid coil. In the rare instances in which the bicycle-mounted magnet of Lahos would accumulate metallic debris, the failure is readily detected and then the magnet can also be easily cleaned by the rider.
In contrast to Lahos' bicycle case, a railway environment is rife with metallic debris which would foul the apparatus of Lahos and, as a train of railcars has few operators, failures are unlikely to be detected in a timely manner. Costs of maintenance would escalate if inductive magnets on all train car wheels required cleaning at each servicing or more frequent servicing to ensure reliable magnetic fields. As well, the need to modify the wheel supports, axles or axle endcaps for installing two separate components would add significantly to the installation costs. One also readily recognizes the inherent delicate nature of the inductive solenoid and magnet arrangement of Lahos and the risk of damage if positioned on the outside of a railcar wheel.
In an earlier attempt to improve the power output of wheel mounted generators, Thomas et al in U.S. Pat. No. 4,539,496 have taught that it is the offset position of the generator from the axis of rotation of the wheel that results in a gear “step-up” of the mechanical driving force of the generator resulting in increased electrical power output.
Further attempts to produce increased amounts of electricity from wheel mounted generators have resulted in the use of multiple sets of coils and magnets, positioned offset the axis of rotation of the wheel, inside a housing. One problem inherent with the offset use of multiple magnet and coil generators is the strength of the attraction of the magnets for the metal core in the coils, which may, if large enough, cause the pendulous mass inside the housing to begin rotating about its axis of suspension, along with the rotating housing, and effectively terminating the objective of generating power.
A number of approaches to prevent co-rotation of the pendulum with the wheel generator housing have been suggested. In recently issued U.S. Pat. No. 6,116,763 to King, an asymmetric weight is attached to the pendulum in much the same way counterweights were used in earlier references for wheel-mounted rotating devices, such as hub odometers. The addition of the counterweight addresses co-rotation caused by frictional drag, but it does not fully address co-rotation caused by the attraction between the magnet and the coil core.
Further, there are other cases in which the rail industry has gone to extraordinary effort to provide indicating apparatus for hot bearings and the like. For instance, it is known to provide hot box detectors adjacent the rails and if the detector spots a hot box (a hot journal or wheel bearings indicating onset of failure) then a signal is sent to a dispatcher who then warns the train operator by radio. Detection of a hot box have conventionally been by infrared detection, based on a measurements taken only as the rail wheel passes a sensor and are thus subject to incorrect readings. Further, the hot box detectors tend only to detect hot boxes near failure, when the temperatures are sufficiently high to ensure detection. Further, sensors in the detectors, such as the bolometer, require a highly stable and accurate high voltage supply. Others, such as pyroelectric cells have a lower power requirement but exhibit a variable response, dependent upon infrared exposure and its strength. If there was an onboard and wheel-powered sensor, then more sensitive data and cumulative readings could be obtained and thus transmit more comprehensive data to a track-side receiver, or to the locomotive.
Clearly, there is a need to provide a reliable, low cost status and warning light system which preferably combines the simplicity and low power requirements of the Lahos system, but is suitable for the rough industrial environment of trains and railcars, prevents co-rotation of the non-rotational elements with the rotati
Goodwin Sean W.
Husar Stephen
Zeade Bertrand
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