GB2337078A

GB2337078A - Emergency exit warning arrangement

Info

Publication number: GB2337078A
Application number: GB9910258A
Authority: GB
Inventors: John Cooper; Paul Merrick
Original assignee: Yale Security Products UK Ltd
Current assignee: Security Products UK Ltd
Priority date: 1998-05-06
Filing date: 1999-05-05
Publication date: 1999-11-10
Also published as: GB9910258D0; GB9809552D0

Abstract

An emergency exit warning arrangement comprises an emergency exit release device having combined therewith an electrically operable warning device which can be operated when it is required to draw attention to the location of the release device. For example, as shown, a row of light emitting diodes D and a light sensor 12 can be provided on the release bar. Alternatively other means for producing visible or audible warning can be provided either integral with the release device or in a portable component secured thereto.

Description

1 2337078 EMERGENCY EXIT WARNING ARRANGEMENT This invention relates to a

warning arrangement for an emergency exit and has for its object to provide a convenient means for drawing attention to the location of a release device for the emergency exit. More particularly, but not exclusively, the invention is concerned with the provision of a warning arrangement for a panic bolt release bar.

In accordance with the broadest aspect of the invention, there is provided an emergency exit warning arrangement that comprises an emergency exit release device having combined therewith an electrically operable warning device which can be operated when it is required to draw attention to the location of the release device.

The warning device may comprise a visual andlor audible warning device.

Preferably, the warning device comprises a plurality of electrical light emitting elements arranged on the release device, an energiser circuit for causing the fight emitting elements to be driven, and an ambient light level detecting device for causing the energiser circuit to be activated whenever the ambient light level fails below a predetermined threshold.

Conveniently, the release device comprises a panic bolt release bar and the light emitting elements are spaced along the length of the bar.

The light emitting elements are preferably in the form of light emitting diodes.

Preferably, the energiser circuit is arranged to flash the light emitting elements.

2 An example of the invention is shown in the accompanying drawings in which:

Figure 1 is an elevation of an emergency exit door; Figure 2 is an enlarged fragmentary view of a panic bolt mechanism provided for the emergency exit door; Figure 3 is an end elevation of the panic bolt mechanism; Figure 4 is an enlarged fragmentary view of a release bar which forms part of the panic bolt mechanism; Figure 5 is an electrical circuit diagram of an energising circuit; and Figure 6 is circuit diagram of a power supply circuit for the energising circuit of Figure 5.

Figures 1 to 3 show an emergency exit with a double leaf door and a panic bolt 10 for each door. The panic bolt is driven by a release bar 11. In the usual way, pressing the release bar 11 causes the bolt to be withdrawn so that the door can be opened.

As shown in Figure 4, the release bar 11 has a row of high intensity light emitting diodes D mounted on it at spaced positions along its length. Adjacent an end of the release bar, there is provided an ambient light level detector 12.

The detector 12 is connected to one input terminal of the input stage of an 3 energiser circuit as shown in Figure 5 driven by a power supply circuit as shown in Fig 6 that includes a 6V battery. This input stage consists of a voltage comparator ic 13 which includes an internal reference voltage generator. This internal reference voltage generator is used to provide current to the detector 12 via a resistor 14 and to apply a threshold level signal to the other input terminal of the comparator ic via a resistor chain 15, 16. It is also used to provide hysteresis via a resistor chain 17, 18, to prevent spurious switching of the comparator output should detector output fluctuate around the threshold level. Typically the resistors 15 and 16 have the same high (approximately 1.OM) ohmic value, so that the comparator operates when the resistance of the detector 12 is substantially equal to that of the resistor 14, going high so as to activate the energiser circuit.

The output of the comparator ic is applied to one input of a NAND gate 19 and also, via a resistor 20 and a capacitor 21 to the base of an npn transistor 22. The base of transistor 22 is connected to a ground rail by a resistor 23 and its emitter is also grounded. A resistor 23a connects the collector of transistor 22 to a supply rail from the power supply circuit, so that transistor 22 acts as an inverting amplifier. The output from the collector of the transistor 22 is normally high, but goes low for a time determined by the values of resistor 20 and capacitor 21 whenever the output of the comparator 13 goes high. The output of the transistor amplifier 22 is used to set a latch circuit comprising two cross-connected NAND gates 24 and 25. The output of the latch is taken from NAND gate 24 and is applied to the second input of the NAND gate 19.

The output of the NAND gate 19 is connected to the RST input of a counter ic 26 which includes a built in clock utilising resistors 27 and 28 and a capacitor 29 to provide a clock frequency of about 1 0Hz. One 4 output of the counter ic, provides divided down output pulses at one thirty-second of the clock frequency, ie about 0.3 Hz. A NAND gate 30 connected to this output of the counter 26 by a capacitor/resistor combination 31, 32 provides driving pulses of about 200ms duration every 3 seconds approximately to a pnp output transistor 30a, which drives the leds D.

Another output of the counter 26 provides a further divided down output at a frequency of about 0.6 mHz, ie at a periodicity of about 14 minutes. This output is used to reset the latch formed by NAND gates 24, 25, via a resistor/capacitor circuit 33, 34, 35 and a transistor amplifier 36. Thus, in use. once the energiser circuit has been activated, it will be reset either when the detected light level rises above the threshold (by a sufficient amount to overcome the hysteresis), or after 14 minutes, whichever occurs sooner.

The circuit also incorporates a low battery detection circuit which includes a pnp transistor 37 which has its base connected by a resistor 37a to the collector of the transistor 22. The transistor 37 is thus switched on for the duration of the output pulse of the transistor 22 when the ambient light level falls below the threshold level. Connected in the collector circuit of the transistor 37 is a zener diode 38 and two resistors 39 and 40 in series. An npn transistor 41 has its base connected to the junction of resistors 39 and 40. The emitter of the transistor 41 is grounded and its collector is connected to the collector of the transistor 38 by a resistor 42 and a light emitting diode 43 in series. A dummy load resistor 44 is connected between the collector of transistor 37 and the ground rail. When the battery is fresh, the led 43 flashes on briefly whenever the transistor 37 is turned on. This can be provoked by covering the detector 12 to test the battery voltage. The circuit is such that if the battery voltage drop caused by current drawn by the dummy load resistor 44 when the transistor 37 is turned on is sufficient to reduce the voltage at the coliector of transistor 37 to less than the zener breakdown voltage of the diode 38, the led 43 will not flash.

It will be understood that the discrete component circuit described above could be replaced by a simple microprocessor circuit programmed to carry out exactly the same functions. An interface with a fire alarm or emergency lighting system could be provided.

In its broadest aspect, the invention may include many types of warning device other than high intensity leds, such as, for example, an audible warning device which is used alone or in conjunction with a visible warning device. The audible warning device may include, for example a speech synthesiser.

The warning device may be operated other than by a built-in light detector as described above. It could, for example be part of a radio, ultrason infrared or hard-wired network.

ic, Power for the warning device may be provided by means other than the battery driven power supply circuit described above. For example, rechargeable cells could be employed which are held in a charged condition either from mains power or from photocells.

The arrangement described could be provided in a separate bolt on device for fitting to existing emergency exits.

6

Claims

1. An emergency exit warning arrangement comprising an emergency exit release device having combined therewith an electrically operable warning device which can be operated when it is required to draw attention to the location of the release device.

2. An arrangement as claimed in claim 1, wherein the warning device comprises a visible warning device.

3. An arrangement as claimed in claim 1 or 2, wherein the warning device comprises an audible warning device.

4. An arrangement as claimed in any one of the preceding claims, wherein the warning device comprises a plurality of electrical light emitting elements arranged on the release device, an energiser circuit for causing the light emitting elements to be driven, and an ambient light level detecting device for causing the energiser circuit to be activated whenever the ambient light level fails below a predetermined threshold.

5. An arrangement as claimed in claim 4, wherein the release device comprises a panic bolt release bar and the light emitting elements are spaced along the length of the bar.

6. An arrangement as claimed in claim 4 or 5, wherein the light emitting elements are light emitting diodes.

7. An arrangement as claimed in any one of claims 4 to 6, wherein the energiser circuit is arranged to flash the light emitting elements when activated.

7

8. An emergency exit warning arrangement substantially as hereinbefore described with reference to the accompanying drawings.