Communications: electrical – Condition responsive indicating system – Specified indicator structure
Reexamination Certificate
2000-04-19
2001-11-13
Lieu, Julie (Department: 2632)
Communications: electrical
Condition responsive indicating system
Specified indicator structure
C340S691100, C340S691300, C340S326000, C340S332000, C340S471000, C340S472000, C340S473000
Reexamination Certificate
active
06317052
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a technique which permits step-wise scrolling, selectively in either of two opposite directions, through a plurality of stored patterns and, particularly, to facilitating the selection of the flash pattern to be produced by an emergency vehicle warning light. More specifically, this invention is directed to a one wire control which enables a flash pattern generator to step, in either of two directions, through a table of instructions commensurate with multiple flash patterns. Accordingly, the general objects of the present invention are to provide novel and improved methods and apparatus of such character.
2. Description of the Prior Art
While not limited thereto in its utility, the present invention has been devised for, and is particularly useful in, the selection of a flash pattern to be generated by a high intensity light mounted upon an emergency vehicle. An emergency vehicle warning or signaling light may employ, as the light generator, an incandescent source, a halogen lamp for example, or a gaseous discharge device, i.e., a flash tube or strobe. Such a light generator may also comprise an array of closely spaced light emitting diodes. The control for an emergency vehicle warning light will typically have the capability of causing the generation of a plurality of different flash patterns. These “standard” patterns will be stored in a pattern table as retrievable controller commands.
The operators of emergency vehicles demand the ability to exercise control over the flash pattern produced by their vehicle mounted warning lights. In the prior art the selection of a stored flash pattern often required the vehicle operator to physically access the control for the flash pattern generator and perform some “manipulation”, i.e., a circuit modification, and/or required the routing of a multi-conductor cable from the control to a selector module located within the driver's compartment. Manipulative steps such as the setting of multiple dip switches at the typically difficult to reach control, a common prior art method of pattern selection, can not readily be performed in the field. The foregoing problem results from the fact that the flash pattern generator control is typically located remotely from the passenger compartment, in a roof-mounted assembly for example, and hard to access. The use of passenger compartment mounted multi-position selector switches is an equally unsatisfactory manner of addressing the problem of flash pattern variation since the number of available patterns is limited to the relative small number of discrete switch positions and, additionally, the expense and inconvenience of connecting and routing a multi-conductor cable is presented. The use of other more complex means for communicating data between the passenger compartment and pattern generator control, wireless techniques for example, is prohibitively expensive and/or volumetrically inefficient.
It should also be noted that the operating environment of a warning light is relatively harsh. This fact dictates a desire to package flash generator control circuitry in a shock-proof, hermetically sealed manner. Such packaging obviously complicates, and often precludes, access for pattern changing.
To summarize, there has been a long standing desire for an uncomplicated and easily useable method of and apparatus for choosing that one of a plurality of stored command signals which will result in, for example, the production of a desired flashing light pattern.
SUMMARY OF THE INVENTION
The present invention overcomes the above-discussed and other deficiencies and disadvantages of the prior art by providing a pattern selection technique which is responsive to changes in the state of a single electrical terminal. The change in state may, for example, be simply the connection of that single terminal to ground. Thus, a pattern change input to a remotely located pattern generator in accordance with the invention may be delivered via a single conductor.
The technique of the present invention employs the duration of changes in the state of the single input terminal as directional control information to implement stepwise scrolling through the plurality of stored patterns. If the duration of the change of state of the input terminal is between first preselected minimum and maximum values, the stepping will precede in a first direction. If the duration of the change in input terminal state is greater than the first maximum, the stepping will occur in a second, opposite direction. If there are no changes in input terminal state within a time period which exceeds a second maximum duration, for example if the input terminal remains grounded, a command signal commensurate with the pattern stored at the address of the last step in the scrolling through the stored patterns will be retained and used as the input to a light generator controller.
In accordance with a preferred method of practice of the invention, the state of the input terminal may be varied by means of the momentary closure of a normally open switch or by providing a pair of terminals that may be momentarily and easily bridged by a conductor.
Also in accordance with a preferred embodiment of the invention, information commensurate with the predetermined patterns is stored in memory, and a word, i.e., a pointer to the full memory address of stored pattern information, will be incremented or decremented as a function of the time the state of the input terminal deviates from its normal state. Each time the pointer is changed, a test is conducted to see if the new pointer is commensurate with the desired pattern. If test is satisfied, the full address of the newly selected pattern is stored and used.
REFERENCES:
patent: 4868540 (1989-09-01), Housley
Stopa James L.
Welling Paul C.
Alix Yale & Ristas, LLP
Lieu Julie
Whelen Engineering Company, Inc.
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