US 3840871 A
Description (OCR text may contain errors)
United States Patent 1 91 1111 3,840,871 Eguchi et al. v Oct. 8, 1974  CONTROL SYSTEM FOR AN ALARM 3,585,620 6/1971 Durand 340 222 INSTALLATION HAVING A REMOTE 3,588,893 6/1971 McCloskey TRANSMITTER WITH A REMOTELY 3,643,244 2/1972 Levy 340/4l8 CONTROLLED EMERGENCY DEVICE  Inventors: Yoshihiro Eguchi; Yasaburo Adachi; 'f h Caldwell Katsutoshi Kuwabara an of Tokyo, Assistant Exammer-ihchard P. Lang Japan Attorney, Agent, or FzrmLane, Aitken, Dunner &
- Ziems  Assignee: Hochiki Corporation, Tokyo, Japan  Filed: Dec. 19, 1972 21 App]. No.: 316,460  ABSTRACT A control system for use with emergency devices uti-  Foreign Application P i it D t lizes an alarm installation having a plurality of transoecr 29 1971 Japan 46-3239 miners and a Single common receive Each transmit ter is provided with a memory contact which re-  US 340/310 R 340/213 R 340/418 mains closed after the transmitter has generated an 340/289 alarm signal. An oscillating control voltage is fed from 511 Int. Cl. .Q ..-H04m 11/04 the receiver through the t actuate 5 Field of Search 340 310 2 3 R 41 227 gency device at any time after the alarm signal. The
340/228 222 169/2 R memory contact is reset by sending from the receiver a reset pulse voltage having an on period longer  References Cited than that of the control voltage.
UNITED PATENTS 12 Claims, 2 Drawing Figures 3,508,233 4/1970 sugiyama 340/222 1 l RESET m 1 SELF-HOLDlNG /"l CONTACT 411 I l LAY LALARM RE ENSING 1Q ELgigENT 1 4 1 .i- I I D l 1 R SET 15 J PAIENTEDBBI 81974 $840,871
l 6 v F G2 CONTROL EMERGECSVCY DEVICE SWITCH 7 RESET 4 KEY A I T RELAY ii E CONTACT P R6 24o SELF*HOLDING I I 2 CONTACT 4a /TRANSM ITTER 2O l SET CONTROLLED 3 com DEVICE 24 (RELAY) :/26T1 E' R Z 8 R ENSlNG ELEMENT g 2-- Rgz; R D4 I T 10 4 E IE R I J CONTROL SYSTEM FOR AN ALARM INSTALLATION HAVING A REMOTE TRANSMITTER WITH A REMOTELY CONTROLLED EMERGENCY DEVICE BACKGROUND OF THE INVENTION This invention relates to a control system which utilizes an alarm installation for signal transmission. Typical fire alarm systems employ a plurality of transmitters stationed at different points in a building, for example, and a single common receiver at another location. Each transmitter is connected by wire to the receiver and sends an alarm signal when it has detected an abnormal enviromental state such as smoke or extreme heat. The receiver sounds an alarm upon receipt of the alarm signal. Alarm installations of this type, in general, are used exclusively for generating an alarm and are rarely used for any other purpose. More sophisticated fire alarm systems will be needed in the future to cope with the increasing size and complexity of modern buildings. Besides alarms, large buildings should be provided with emergency fire control and safety devices such as guide lamps, emergency exit lamps, fire shutters, smoke shutters, and smoke exhaust fans as well as fire extinguishers. If the existing fire alarm installation could be partly utilized to control these emergency devices, automatically controlled operation of the system could be achieved at relatively low cost.
Emergency equipment is usually designed to be activated at the first sign of fire. However, such equipment should not always be actuated immediately when a fire breaks out. For example, a fire shutter should not be closed with a person trapped in a room, and smoke exhaust fans need not always be started even though a room has been evacuated. These emergency devices should not be linked directly to fire detectors but should be actuated selectively upon proper judgement of the situation at a central receiving station.
An indicator lamp is sometimes installed at the transmitter site to provide a convenient means for identifying the transmitter which has generated the alarm signal as well as for operational tests. The usefulness of the lamp may be enhanced if it is lighted only when it is really required or is cyclically flickered in order to be more conspicuous to the human eye. In conventional alarm systems, however, the lamp is turned on continuously when the transmitter is actuated.
SUMMARY OF THE INVENTION A control system which utilizes an alarm installation according to the invention is provided with a memory" contact which is adapted to be closed in response to the operation of a transmitter. The contact remains closed until a reset voltage is received. By supplying a control voltage from the receiver to the controlled device via the memory contact, the device can be actuated whenever required.
The control system according to the present invention can accomplish the reset operation by employing a reset voltage which is of the same polarity as that of the control voltage but has a longer on period than that of the control voltage.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic circuit diagram illustrating an example of a control system of the present invention.
FIG. 2 is a schematic circuit diagram illustrating an example of a controlled device.
DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1, a receiver 10 comprises a power supply 2, an alarm relay 4, an oscillator 6, a transistor switching circuit 12 responsive to the oscillator 6, and a relay 8 controlled by the circuit 12. One end of the power supply 2 is connected to a terminal I, of the receiver through a stationary contact 8b and a moving contact of the relay 8, and the other end thereof is connected to a terminal of the receiver through a reset key K2 and the alarm relay 4. The contacts 8b and 8c are normally closed. The relay 8 also has a stationary contact 8a which is connected to the other end of the power supply 2 through a resistor R1. A control switch K, operates the oscillator 6 which may be a multivibrator or other conventional type of oscillator. When the control switch K, is closed, the oscillator 6 is energized by the power supply 2 and generates a rectangular pulse voltage consisting of an on period and an off period. The generated voltage of rectangular wave shape is produced at output terminals t and of the oscillator 6. The switching circuit 12 includes transistors Tr, .and Tr The collector of the transistor Tr, is connected to the emitter of the transistor Tr through a register R and the emitter of the transistor Tr is connected to the terminal t which is connected to one end of the power supply 2. The terminal 2 is connected to the other end of the power supply 2 through a resistor R The base of the transistor Tr, is connected to the output terminal t of the oscillator 6 and also is connected to a capacitor C, through a resistor R and a diode D,. The junction of the, capacitor C, and diode D, is connected to one end of the power supply 2 through a reset key K and the other end of the capacitor C, is connected to the other end of the power supply 2. The base of the transistor Tr, is connected to the collector of the transistor Tr, through a resistor R and the collector of the transistor Tr, is connected to the other end of the power supply 2 through the coil 8d of the relay 8.
A pair of external lead wires 1, and 1 are connected to terminals t, and t of the receiver, and the lead wires l, and 1 run a transmitter 20 representative of a plurality of similar transmitters installed in monitored areas.
The transmitter 20 has a diode bridge 22, a controlled device 24, an operation memory contact 26a and a reset circuit 40 therefor, a thyristor switching element SCR,, and asensing element or detector 32.-The input terminals of the diode bridge 22 are connected to the lead wires 1, and I, through the transmitter terminals t and t.,, and the output terminals of the diode bridge 22 are connected to bus wire lines I and 1 in the transmitter 20. Due to the function of the diode bridge 22, the polarity of the voltage which appears at the bus wires 1 and l, is constant irrespective of connection polarities of the lead wires 1, and 1 to the transmitter 20, thereby preventing erroneous operation of the transmitter 20. As shown in FIG. 2, the controlled device 24, in this example, is a relay which has a contact 24a adapted to control an emergency device 30 which may be a guide lamp, a fire shutter, a smoke exhaust fan, or other device. Alternatively, an indicator lamp to indicate the operation of the transmitter 20 may be used instead of a relay for use in the controlled device 24.
' The operation memory contact 26a is preferably a contact of a latching relay 26 which has a set coil Rp and a reset coil Rs. Turning to the set circuit, the set coilRp is connected between the bus wires 1 and 1 in series with a diode D a capacitor C and a resistor R A resistor R is connected in parallel with the set coil Rp and the diode D In the reset circuit 40, the reset coil Rs is connected between the bus wires 1 and in series with the memory contact 260, a diode D and a thyristor SCR A capacitor C is connected in parallel to the thyristor SCR and the reset coil Rs. The trigger electrode of the thyristor SCR is connected to the bus wire 1 through a resistor R and also is connected to a triggering capacitor C through a zener diode Z The capacitor C is connected to the bus wire 1 through the parallel circuit consisting of a resistor R and a diode D and through the memory contact 26a.
A sensing element 32 is used to provide an output signal in response to change in the environmental condition. A conventional type of sensor may be used for the sensing element 32. One end of the thyristor SCR is connected to the bus wire 1 and the other end of the thyristor SCR, is connected to the bus wire 1., through a capacitor C The capacitor C is connected to the resistor R through a diode D Under the normal monitored environmental condition, the power supply 2 of the receiver supplies power through the lead wires 1, and 1 to the bus wires 1 and 1 When fire breaks out, the sensing element 32 produces an output signal with which the thyristor SCR is triggered and driven into the on state. The capacitor C which is connected in series with the thyristor SCR normally is discharged through the resistor R When the output signal is applied from the sensing element 32, the lead wires 1 and 1 are short-circuited with the thyristor SCR, and the capacitor C and, consequently, the alarm relay 4 in the receiver 10 is energized to generate an alarm signal and to close its selfholding contact 4a. In the transmitter, the capacitor C, is normally charged by the bus wires 1 and I, through resistors R and R When an output signal is applied from the sensing'element 32 and the thyristor SCR, is driven into the on state, the charge of the capacitor C is discharged through the circuit consisting of the diode D the set coil Rp, the thyristor SCR, and the diode D thereby energizing the set coil Rp of the latching relay. Consequently, the contact 26a is closed and the controlled device 24 alone is connected to the bus wires 1 and 1 However, because the self-holding contact 4a of the alarm relay 4 is closed, the lead wires 1, and 1 are short-circuited and provide no voltage and, therefore, the controlled device 24 is not energized.
For the controlled device 24 in this example, a relay coil of the slow releasing type is employed. For actuating the controlled device 24, the control switch K, of the receiver 10 is closed. When the switch K, is closed, the oscillator 6 generates a pulse signal whose on period is shorter than its off period. This pulse signal is applied to the transistor Tr from the terminal As the pulse signal is applied, the transistor Tr, energizes the relay 8 intermittently via the transistor Tr thereby switching its movable contact 8c between its stationary contacts 8a and 8b repeatedly. When the contact is thrown into contact with the contact 8a, a negative voltage is supplied to the lead wire 1 and a positive voltage is applied to the lead wire 1 energizing the controlled device 24 at the transmitter site. The contact 24a (FIG. 2) is closed thereby starting the actuating motor, for example, of the emergency device 30. Since a slow releasing relay is used for the controlled device 24 which is intermittently energized, its contact 24a is prevented from synchronous on-off operation. However, if an indicator lamp is used in place of the controlled device 24, the lamp is on-off controlled with the control voltage to indicate the operating state.
When the voltage is intermittently applied to the lead wires 1 and 1 the bus wires 1 and 1 are not shortcircuited by the thyristor SCR even ifv it is turned on by the output of the sensing element 32. This is because the capacitor C has already been charged or is instantaneously charged when the voltage is applied.- The capacitor C of the reset circuit 40 is energized when the voltage is intermittently fed to the lead wires 1, and 1 However, the terminal voltage of the capacitor C does not rise to a sufficiently high level to break down the zener diode 2 because the charge of the capacitor C is discharged through the diode D and the controlled device 24 during the off period of the pulse voltage.
The memory contact 26a can be reset by momentarily closing the reset key K, of the receiver 10. When the reset key K is closed the capacitor C is charged with the voltage of the power supply 2. The charge of the capacitor C is discharged through the circuit consisting of the diode D,, the resistor R the base and emitter of the transistor Tr plus the resistors R and R During the period for which the discharge current flows, the relay 8 is kept energized and its moving contact 80 is kept in contact with its stationary contact 8a for a longer period of time, thereby providing a pulse current of a wider pulse width or on period to the transmitter 20. The capacitor C of the transmitter 20 is charged for a longer period of time and the terminal voltage of the capacitor 20 ultimately reaches a level sufficiently high to drive the zener diode 2 into the reverse conducting state. As the zener diode Z becomes conductive, the thyristor SCR is triggered into the conducting state and consequently the reset coil Rs is energized. As a result, the memory contact 260 is reset or opened and the controlled device 24 is de-energized or turned off.
As described above, this invention provides means to selectively control emergency devices which are related to alarm-generating sensors, simply by adding to an already-installed fire alarm installation, the oscillator circuit 6, the controlled device 24, the memory contact 26a, and the reset circuits 28 and 40 for use with the memory contact 26a. It is possible to automati cally start the emergency device by driving the control switch K with the alarm relay 4, if desired. Simultaneous resetting of the alarm relay 4 and the controlled device 24 can be achieved by breaking the reset key K (HQ. 1). Since the contact 260 memorizes" that the sensing element 32 has generated an alarm, the memory contact 26a is not reset even when the lead wires 1, and I are de-energized and, therefore, the controlled device can be immediately operated when the control pulse is supplied.
Thus, the circuit described above can be easily adapted to perform different operations, for example: selective remote activation and deactivation of emergency equipment; automatic activation and selective remote deactivation of equipment; and automatic or selective remote activation and deactivation of a flickering indicator light or other signal means at the transmitter site. This versatility allows a variety of uses of the same alarm system. The system is shown in connection with fire detection apparatus only for illustration, and is similarly applicable where conditions other than fire, such as nuclear radiation, are being monitored at a central station with one or more detection sites.
The present invention is not limited to the above illustrated example but can be embodied in various ways within the scope and spirit of the appended claims.
1. A control system for an alarm installation equipped with a receiver adapted to be connected to a power supply and having alarm relay means, and a remote transmitter connected through lead wires to said receiver, said transmitter having a sensing element for detecting an abnormal condition and a switching element to actuate said alarm relay means in said receiver by connecting said lead wires, wherein the improvement comprises: said receiver including a self-holding alarm relay contact responsive to actuation of said alarm relay means to connect said lead wires and means for selectively introducing a control voltage and a different reset voltage into said lead wires, and said transmitter including a controlled device and a memory switch serially connected between said lead wires, a latching relay responsive to detection by said sensing element for closing said memory switch to connect said controlled device between said lead wires to receive said control voltage when introduced, said latching relay holding said memory switch closed until said reset voltage is introduced by said receiver, said control voltage operating said controlled device without opening said memory switch.
2. The control system of claim 1, further comprising an indicator lamp which serves as said controlled device.
3. The control system of claim 1, further comprising a slow releasing relay having a contact to control an emergency device which serves as said controlled device.
4. A control system utilizing an alarm installation, comprising a receiver adapted to be connected to a power supply and having alarm relay means; a sensing element located remotely from said receiver for detecting an abnormal condition; two lead wires connecting said sensing element to said receiver; and a transmitter which has a thyristor responsive to said sensing element to connect said lead wires to drive said alarm relay means; said receiver having a self-holding alarm relay contact responsive to said alarm relay means for deenergizing said lead wires and said receiver having means to introduce-into said lead wiresa pulse control voltage consisting of alternately repeated on and off periods and also to introduce a reset voltage, the on period of which is longer than that of said pulse control voltage, said transmitter having a capacitor which is connected in series with said thyristor to cut off said thyristor after being charged, a discharge resistor which is connected in parallel with said capacitor, a slowreleasing relay which controls an emergency device,
and a memory contact which closes when said thyristor is driven into the conductive state bysaid sensing ele ment for connecting said slow releasing relay to said lead wires until said reset voltage is applied.
5. The control system of claim 4, wherein said transmitter has a latching relay with a setting coil, a resetting coil and a contact serving as said memory contact, said set coil closing said memory contact when said set coil is energized by the discharge current of said capacitor when said lead wires are connected by said thyristor, another thyristor interconnecting said memory contact and said resetting coil with said lead wires, said resetting coil being energized to open said memory contact when said other thyristor is driven into the on state, and a trigger capacitor for driving said other thyristor above a predetermined level by said reset voltage.
6. The control system of claim 4, wherein said means of introducing said pulsed control voltage and said reset voltage includes a control relay with a coil and a relay contact for cutting out a certain section of said lead wires and connecting the power supply to the cutout section, an oscillator for supplying control voltage to said control relay coil, a control switch for operating said oscillator, a reset capacitor for supplying reset voltage to said control relay coil, and reset switch means for charging said reset capacitor.
7. A control system for selectively energizing a controlled device through an alarm installation, comprising a receiver having alarm relay means, a remote transmitter having a detector for producing an alarm signal indicative of an abnormal condition and switch means responsive to said alarm signal, an electrical circuit between said transmitter and receiver interconnecting said alarm relay means andsaid switch means, said switch means closing said circuit in response to said alarm signalto energize said alarm relay means, said transmitter having amemory switch for interconnecting the controlled device to said circuit in response to said alarm signal, said receiver having means responsive to said alarm signal for de-energizing said circuit without deactivating said alarm relay means to prevent said alarm signal from directly activating said controlled device, and said receiver having means for selectively energizing and de-energizing said controlled device via said circuit and said memory switch.
8. The system of claim 7, wherein said means for energizing and de-energizing said controlled device produces in said circuit a first pulse voltage having a regular on period to activate said controlled device.
9. The system of claim 8,'further comprising slow release relay means for interconnecting said memory switch means and the controlled device such that the controlled device is continuously activated by said first pulse voltage. 7
10. The system of claim 8, wherein said energizing and de-energizing means produces in said circuit a second pulse voltage having an on period longer than that of said first pulse voltage, said receiver having means nonresponsive to said first pulse voltage for reopening said memory switch in response to said second pulse voltage to turn off the controlled device.
11. A control system for an alarm installation, comprising a receiver with a self-holding alarm relay. a remote transmitter with a controlled device and means for generating an alarm signal, electrical lead wires interconnecting said receiver and transmitter, said transmitter having means responsive to said alarm signal for operatively connecting said lead wires to activate said alarm relay in said receiver, said transmitter having latching relay switch means responsive to said alarm signal for simultaneously connecting said controlled device in circuit with said lead wires, said latching relay switch means being resettable to disconnect said controlled device in response to a reset voltage pulse of predetermined minimum duration, means in said receiver responsive to said alarm relay for simultaneously tively connected to said slow-releasing relay such thatsaid pulsed control voltage is of sufficiently short period to keep said emergency device continuously energized via said slow-releasing relay without resetting said latching relay switch means.