Communications: electrical – Land vehicle alarms or indicators – External signal light system
Reexamination Certificate
1999-08-10
2001-09-18
Hofsass, Jeffery (Department: 2736)
Communications: electrical
Land vehicle alarms or indicators
External signal light system
C340S332000, C315S083000, C362S208000
Reexamination Certificate
active
06292097
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates generally to warning or hazard alert lighting systems and more particularly to a multiple visual alert device having variable mode operational capability.
2. Background
A wide variety of equipment, including mobile emergency, maintenance and law enforcement vehicles, employ a variety of signaling devices, both audible and visual. Visual alert devices commonly used in connection with these types of applications include flashing or flash simulating devices. Flashing devices may include strobe lights, rotating halogen devices, rotating sealed beam devices, flashing incandescent devices and devices which may include an array of light emitting diodes (LED).
The prior art recognizes generally the benefit in providing strobe pulse control, see Pacelli, U.S. Pat. No. 5,602,522, Visual Signaling System. In particular, the prior art recognizes that providing for a constant flash rate for strobe lights connected in an array may be of benefit. According to the prior art, constant flash rate for strobe lights has been achieved utilizing a single control circuit electrically connected to more than one strobe which signals each strobe individually to discharge simultaneously and at a constant rate. This type of system has a distinct disadvantage of relying on an additional and external component to trigger and therefore control strobe operation.
It may be desirable to provide a visual alert system that has either an alternating mode operational capability or a synchronous mode operational capability or in the alternative, both an alternating mode operational capability and a synchronous mode operational capability. It may also be desirable to provide either an alternating mode operational capability or a synchronous mode operational capability for strobe lights or other visual alert devices which are connected in an array which eliminates the need for a separate control device to operate and control the array of visual alert devices. In addition, it may be desirable to provide a visual alert system that has both an alternating mode operational capability and a synchronous mode operational capability which eliminates the need for a separate control device to operate and control an array of visual alert devices.
SUMMARY OF THE INVENTION
Accordingly, these and other objectives are achieved by a visual alert system having variable mode operational capability that includes two or more visual alert devices electrically interconnected to form an array. By variable mode it is meant alternating mode, both single and multiple pulse, synchronous mode both single and multiple pulse as well as the variations that may be achieved employing the present invention.
In one embodiment of the invention, the array may include a first visual alert device including a first control circuit and a second visual alert device including a second control circuit. The first and second control circuits are interconnected by way of a flash mode interconnect line. The first and second control circuits, thus interconnected are capable of sensing changes in voltage between the first and second strobe control circuits and therefore between the first and second visual alert devices.
In one embodiment of the invention, the first visual alert device includes a first strobe and a second strobe. In this embodiment of the invention, the first visual alert device includes a first strobe control circuit and the second visual alert device includes a second strobe control circuit. The first strobe control circuit and the second strobe control circuit, specifically, a first strobe control circuit microcontroller and a second strobe control circuit microcontroller, are interconnected by a flash mode interconnect line which, in the case of alternating mode operation is designated as an alternating flash mode interconnect line.
In one embodiment of the invention, the visual alert system the system operates in an alternating mode. In this embodiment of the invention, the visual first and second visual alert devices flash in a sequential manner wherein a first visual alert device is energized or discharges, followed by an interval between the energization or discharge of the first visual alert device and the second first visual alert device, followed by the energization or discharge of a second visual alert device. In the alternating mode the first and second visual alert devices may alternate flashing in single as well as multiple flash mode i.e. dual, quad, etc.
In the alternating mode operation, whenever either strobe flashes, it pulls the voltage across the alternating flash mode interconnect line low. Upon power up, each strobe begins operating norm ally, pulling the alternating flash mode interconnect line low when flashing. At this point, both the first and second strobe lights are flashing simultaneously. When the strobes are not flashing, their respective strobe control circuits monitor the alternating flash mode interconnect line to see if it gets pulled low. After an unspecified interval, the strobes will be slightly out of sequence. The first of the two strobes to detect a drop in voltage across the alternating flash mode interconnect line assumes operation as a slave strobe, with the other serving as a master strobe. The slave strobe monitors the alternating flash mode interconnect line for a preselected higher value indicating that the master strobe has completed its flash or flash sequence. Before discharging, the slave strobe delays a preselected delay interval depending upon the operational characteristics of the particular preselected flash program, i.e. single, dual or quad mode. During the slave strobe's flashing sequence, the master strobe monitors the alternating flash mode interconnect line for a preselected higher value indicating that the slave strobe has completed its flash or flash sequence. Flash intervals and delay intervals may be timed in incremental intervals.
The master strobe delays a preselected delay interval, once again depending upon the operational characteristics of the particular preselected flash program, before energizing. The system thereby achieves alternating flash mode and remains in that mode and the process sequence is repeated until the system power is switched off or the operational mode is changed.
In an alternate embodiment of the invention, the visual alert system the system operates in a synchronous mode. In this embodiment of the invention, the first strobe control circuit and the second strobe control circuit are interconnected by the flash mode interconnect line which in the case of synchronous mode operation is designated as a synchronous flash mode interconnect line. Whenever either strobe flashes, it pulls the voltage across the synchronous flash mode interconnect line low. In the case of synchronous mode operation, the first and second visual alert devices flash in a substantially synchronous mode wherein a first visual alert device is energized or discharges, in some cases more than once, followed by the substantially synchronous energization or discharge of a second visual alert device, followed by a dead interval between energization or discharge of the first and second visual alert devices. In the synchronous mode the first and second visual alert devices may flash in single as well as multiple flash mode, i.e. dual, quad, etc.
In the synchronous mode, upon power up, each strobe begins operating normally, pulling the synchronous flash mode interconnect line low when flashing. At this point, both the first and second strobe lights are flashing simultaneously. When they aren't flashing, their respective strobe control circuits monitor the synchronous mode interconnect line to detect if it gets pulled low. After a few seconds of operation, the strobes will be slightly out of sequence, and a second strobe will detect that the first strobe is pulling the line low. When the predefined low voltage is detected by the second strobe control circuit across the synchronous flash mode interconnect line in
Electronic Controls Company
Hofsass Jeffery
Holland Joseph W.
Previl Daniel
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