US3732554A

US3732554A - Alarm unit

Info

Publication number: US3732554A
Application number: US00145072A
Authority: US
Inventors: J Ginard
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-05-19
Filing date: 1971-05-19
Publication date: 1973-05-08
Anticipated expiration: 1990-05-08

Abstract

An electrically operated unit may be used as a switch in a wide variety of alarm, detection and like systems. The central element of the unit is a neon glow lamp connected between a hot line lead of an alternating current source and a potential load lead, the potential load lead being connected to a sensitivity lead. On the application of an external capacitance to the sensitivity lead capacitive reactance decreases to more brightly light the lamp to activate a photoconductive cell to operate the switch function of the unit. A potentiometer and a variable capacitor are connected between the hot line lead and the potential load lead so as to form a parallel circuit with the lamp with reference to the external capacitance applied to the sensitivity lead. The potentiometer and the variable capacitor regulate the brightness of the lamp and thereby the threshold of activation and the sensitivity of the unit. Other elements in the circuitry of the unit test its function and enable it to reset itself.

Description

United States Patent [191 [111 Ginard [451 May 8, 1973 1 ALA N H T p H Primary Examiner-David L. Trafton [76] Inventor: John Ginard 30 Albany Att0rneyl-lubert T. Mandeville, Fritz L. Schweitzer,

Crescent Bronx NY. 10463 Jr., Michael A. Cornman and Robert P. Grindle [22] Filed: May 19, 1971 57 ABSTRACT PP' NOJ 145,072 An electrically operated unit may be used as a switch Related U.S. Application Data Goldfarb et al ..340/258 C in a wide variety of alarm, detection and like systems. The central element of the unit is a neon glow lamp I connected between a hot line lead of an alternating current source and a potential load lead, the potential load lead being connected to a sensitivity lead. 0n the application of an external capacitance to the sensitivity lead capacitive reactance decreases .to more brightly light the lamp to activate a photoconductive cell to operate the switch function of the unit. A

test its function and enable it to reset itself.

8 Claims, 4 Drawing Figures ALARM UNIT CROSS REFERENCES TO RELATED APPLICATIONS This application is a continuation-in-part of my patent application Ser. No. 872,666 filed Oct. 30, 1969, now abandoned, entitled ALARM UNIT.

BACKGROUND OF THE INVENTION Costly and specialized proximity detection devices are known. This invention provides a less costly and almost universal unit which may be used as a proximity switch and:which also may be used as a switch in an almost endless variety of alarm, signal, control and detection systems.

SUMMARY OF THE INVENTION In the unit, line current flows through the coil of a first relay, through a holding contact of the first relay, through a thermal circuit breaker, and through the normally closed contact of a second relay. Rectified current is connected in series with the coil of the second relay and a photo-conductive cell. The photo-conductive cell is set in a module with a neon glow lamp which may be selectively connected in parallel with a variable capacitor and a potentiometer which have the same return A.C. potential source connected to the outer side of the neon lamp when energized. When additional capacitance touches an alarm unit sensitivity lead, the neon lamp lights up more brightly to allow the photconductive cell to pass current to open the normally closed contacts of the second relay and drop the coil of the first relay out of the circuit. The dropping out of the first relay causes its contacts to activate any desired alarm or other device. According to the setting of a given switch, plug type flashers may be used to reset and/or recycle. the unit after a time interval. If desired, the flashers may be omitted and the unit reset manually by momentarily closing a switch to energize the coil of the first relay which is then held closed by its holding contact as described above.

The basic element of this invention consists of the neon glow'lamp and photo-conductive cell module. The neon lamp is more brightly lighted as capacitance in its circuit is increased. This triggers the unit by means of the photo-conductive cell. The sensitivity of the unit to an increase in capacitance enables it to be used as a proximity switch in a wide variety of applications. Conductive objects of a given capacitance are connected to the unit which is tuned so that, if a human being touches the object, its capacitance is increased and the unit is triggered to activate an alarm. This tuning is accomplished by means of a potentiometer and a variable capacitor connected in parallel with the neon glow lamp between an A.C. hot line lead and a potential load lead having a sensitivity lead connected thereto. The sensitivity lead is connected to external objects to detect an increase in their capacitance as when touched by a person.

In other applications, the unit may be connected to external detectors such as thermostats, photo-conductive cells, and the like. These detectors may or may not be grounded along with the unit to brighten the neon lamp in the module on their activation to trigger the unit.

Thus it may be seen that the unit of this invention is inexpensive, easily manufactured, and may be used in a wide variety of applications.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a circuit diagram of a unit according to a preferred embodiment of this invention;

FIG. 2 is a diagram of the connection of the unit to external detectors and to an object as a capacity detector;

FIG. 3 is a section through a plug type flasher as used in this invention; and

FIG. 4 is a schematic diagram of a relay as used in the unit of this invention.

Referring to FIG. 1, the unit of this invention incorporates the following elements connected by appropriate circuitry. The heart of the unit consists of a module 10 having a case 11 containing a V4 watt neon glow lamp 12 designated NE 57 and a photo-conductive cell 13 such as that bearing identification CL 503- Clairex Photoconductive Cell. The inner surface 14 of the case 11 may be painted white or silvered to augment the light intensity from lamp 12 which reaches photo-conductive cell 13.

The unit also includes a grounded line current plug 15, a reversing switch 16, a grounded outlet receptacle 17, a neon indicating light 18 rated at one-third watt at 125 volts AC, a thermal'circuit breaker 19 of the noncycling, reset type, and a terminal 20 for five

connections

21, 22, 23, 24 and 25. The unit further incorporates two rectifiers 26 and 27 rated at 200-400 MA, a variable capacitor 28 rated at 15.5 to 467.8 MMF, a 5 megohm potentiometer 30 rated at one-half watt, and a relay 31 having the normally open contacts 32, 33 and 34, having the normally closed contacts 35 and 36, and having a relay coil 37 with contacts rated for 10 amps at 115 volts AC. Further included in the unit are

male cap plugs

39 and 40,

receptacles

41 and 42, and

plug type flashers

43 and 44. Finally, the unit includes a single pole three position switch 45, a relay 46, and four resistors 51, S2, 53 and 54, which are, respectively, two each of 8.2 megohms, one of 200,000 ohms, and one of 100 ohms, 5 watts capacity.

As shown in FIG. 4, relay 46 has a coil 47 rated at l0,000 ohms, 3.2 MA. The relay armature 48 with electrical contacts is supported by spring 49 to be normally closed. The armature spring 49 is replaced with one of smaller guage size. This construction renders the relay 46 particularly sensitive.

All the forementioned elements of the unit of this invention are examples of those used in an operating model; however, equivalent elements may be substituted to accomplish the same functions electronically as these are merely illustrative."

The unit of this invention functions and operates in the following manner. Plug 15, by means of leads and 71, conducts current to reversing switch 16 which is thrown to render lead 72 hot and lead 73 neutral. Current flows through leads 74 and 75 to receptacle 41, through the heater coil of flasher 43, to plug cap 39 to lead 76. From lead 76 current flows again through receptacles 42 through the heater coil of flasher 44 and plug cap 40 to receptacle 41 through flasher 43 to cap 39. Current from lead 77 flows through plug cap 40', through flasher 44 and receptacle 42 to lead 78. If

switch 45 is thrown to the left as shown, current from lead 78 will pass through lead 79 to lead 80 and through contact 36 of relay 31 to lead 81, through resistor 54 and leads 82 and 83 to complete a circuit.

FIG. 3 shows the internal construction of

plug flashers

43 and 44 as may be used in this invention. These flashers have an insulated body 55 from which male contacts 56 and 57 extend. The male contact 57 has an extension 58 which terminates within a female contact aperture 59. A bi-metallic strip 60 forms a normally open armature which, when heated, moves against the contact 61 of the female contact aperture 62. A heating element 63 is wound about strip 60 and is connected between male contact 56 and contact 61.

Resistance 54 has a lower resistance than the coil 37 of relay 31 so that it prevents the activation of relay 31 by current which passes through the heating elements 63 of the

plug flashers

43 and 44. After a desired period of time when the bi-metallic strips 60 are heated to contact the contacts 61 of the

flashers

43 and 44, coil 37 will be energized to open contact 36 and close the holding contact 34.

With relay 31 energized, current now flows from lead 72 to lead 85 through the normally closed contact 48 of relay 46 through lead 86 to circuit breaker 19 through lead 87, through the now closed normally open contact 34, lead 80, coil 37, and leads 88 and 83.

Before relay 31 is energized as has been described, lead 89, the normally closed contact 35, and the

leads

90, 91 and 92 light lamp 18 to indicate the unset condition of the unit. When relay 31 is activated to set the unit, contact 35 opens to disconnect lamp 18 and to deenergize receptacle 17.

Lead 73 conducts current to rectifier 26 so that a DC voltage is impressed on phot-conductive cell 13 by lead 93. Lead 94 extends from cell 13 through coil 47 of relay 46 from which lead 95 passes through rectifier 27 to lead 96.

An AC voltage is impressed on lamp 12 by picking up current passing through the closed normally open contact 34 to leads 80, 79 and 97. If the unit is capacity energized by an external capacitance applied to lead 100 for test purposes and only contact 23 is connected to the sensing lead 100, current will fiow through bulb 12 to lead 101 to light it. When lamp 12 lights, photoconductive cell 13 passes a current to coil 47 to open the armature 48 of relay 46. This disconnects holding contacts 34 and coil 37 of relay 31 to drop it out energizing receptacle 17 for alarm purposes.

Receptacle 17 is connected to a current source by leads 73, 102, 103, 90, the now closed normally closed contact 35, and leads 89 and 72. Thus any alarm or other device can be connected to receptacle 17 to be activated on the capacitance increase or on the grounding of sensing lead 100. A ground 120 extends between plug and receptacle 17. By means of terminals 24 and 25, leads 106 and 107, and contact 32, the grounding or capacitance increase of sensing lead 100 can serve to disconnect a normally functioning piece of apparatus connected through tenninals 24 and 25.

As shown in FIG. 2, the unit 110 of this invention may be grounded by a ground wire 111 Sensing leads 100 and 113 pass through

detectors

114 and 115. Such detectors could be photo-conductive cells, thermostats, or the like which are grounded or connected to conductive capacity 142 by lead 1 12. Thus these detectors may activate unit 110. A ground or other return 118 may be supplied if desired.

Referring again to FIG. 1, after relay 31 drops out, the

plug flashers

43 and 44 will reset and/or recycle the unit after a time interval in the manner which has been described. If switch 45 is moved to the right from the open position shown to make a contact with lead 123, current flows through leads 72, 74, 75, the heating coil of flasher 43, leads 76 and 123, to switch 45 to return in the manner which has been described. Thus it maybe seen that, with switch 45 thrown to the left, the

plug flasher heaters

43 and 44 are connected in series to reset or recycle the unit and with switch 45 thrown to the right, only plug flasher 43 is connected to reset the unit. The use of flashers to recycle a unit is shown and described in my U.S. Pat. No. 3,183,415. If the

flashers

43 and 44 are removed and the

caps

39 and 40 are plugged into the

receptacles

41 and 42, any momentary closing of switch 45 or other remote electrical devices may be used to activate or deactivate the unit.

Referring to FIG. 2, the unit 110 may be used as a proximity switch by connecting lead 100 to lead 125 which contacts an object 126. Upon a person touching the conductive object 126, its capacity will be increased to trigger ofi' the unit in the following manner.

When the unit is recycled or set, contact 33 of relay 31 closes to complete a circuit through lead 127, resistance 53, lead 128, the variable potentiometer 30, lead 129, contact 21, shunt 130, contact 23 and neon lamp l2.

Resistances

51, 52 and 53 reduce any current flow and resulting shock hazard from touching sensing lead 100 to such an extent that no possibility of shock remains. Variable capacitor 28 is insulated from the unit chassis and placed in the circuit with lamp 12 through resistor 52, leads 132 and 133, contact 22 and shunt 130. Thus voltage, current and internal and external capacitance in the circuit with sensitivity lead 100 and lamp 12 can be varied by adjusting potentiometer 30 and capacitor 28 to reduce the brightness of lamp 12 just below a degree required to activate cell 13, drop out relay 31 and trigger the unit. On touching object 126, a person or persons will add to its capacity to increase capacitance and voltage flow above the set value to lamp 12 to brighten it and trigger the unit. It is known that in an alternating current circuit, an increase in external capacity will result in a decrease in current value.

Depending of the size or capacitance of an object 126, potentiometer 30 and capacitor 28 may be adjusted accordingly or removed from the circuit by disconnecting shunt 130. The parallel shunt connections between

terminals

22 and 23 can be used for external capacitance control when disconnected. The triggering of this unit by an increase in capacity allows it to be used in an almost endless number of various applications ranging from touch contact burglar alarms to the detection of fluid level in a container 142.

The thermal circuit breaker 19 may be used to break the circuit to drop out relay 31 and test the recycling of the unit. The automatic recycling feature of the unit is required for many applications. There is a constant alarm when the unit is activated unless it is set to recycle.

From the foregoing, it may be seen that potentiometer 30 and variable capacitor 28 control current through lamp l2 and the external capacitance connected to sensitivity lead 100. With the specific circuitry of this invention, the current is maintained at a low level. Additional external capacitance applied to sensitivity lead 100 causes the neon glow lamp to brighten to activate the unit.

What may be termed a hot line lead of an alternating current source would include leads 72, 85, 127 and 97. What may be termed a potential load lead would include leads 101, 129, 130 and 133. Thus potentiometer 30 and variable capacitor 28 are connected between the hot line lead and a potential load lead so as to form a parallel circuit with reference to an external capacitance applied to sensitivity lead 100.

While this unit has been shown and described in the best form known, it will nevertheless be understood that this is purely exemplary and that modifications may be made without departing from the spirit and scope of invention.

What is claimed is:

1. A highly sensitive electrical detection unit adapted to be finely tuned for triggering by proximity with an object having a predetermined minimum capacitance, said unit including a. hot line lead means adapted to be connected to an alternating current source;

b. potential load lead means having sensitivity lead means connected thereto;

c. a self-contained module mounting in closely spaced relation neon glow lamp means and photoconductive cell means;

d. said neon glow lamp means being connected between said hot line lead means and said potential load lead means;

e. alarm means associated with actuatable relay means;

f. said actuatable relay means being connected in series with said photo-conductive cell means and a second current source, in a manner whereby predetermined triggering capacitance applied to said sensitivity lead means will increase the light output of said neon glow lamp means in said module thereby causing current flow through said photo-conductive cell means, said alarm means being actuated through said relay means;

g. threshold fine tuning means for establishing a minimum triggering capacitance including 'a potentiometer and a variable capacitor connected between said hot line lead means and said potential load lead means to form a parallel circuit with said neon glow lamp means with reference to said predetermined triggering capacitance necessary to actuate said alarm means when said sensitivity lead means is proximate to said triggering capacitance. 2. A highly sensitive detection unit in accordance with claim 1, in which a. said second current source includes diode means rectifying the current from said alternating current source. 3. A highly sensitive detection unit in accordance with claim 2, in which a. said actuatable relay means includes a first relay havin a coil and normal closed contacts and a secon relay having a coil, contacts, and a holding circuit;

b. the coil of said second relay being connected in series through the contacts of said first relay.

4. A highly sensitive detection unit in accordance with claim 3, further including a. current interrupting test means connected in series with the normally closed contacts of said first relay, the coil of said second relay, and said hot line lead in a manner whereby the activation of said test means drops out said second relay;

b. said second relay having normally closed contacts which close on the dropping out of said second relay;

0. said unit being activated through said normally closed contacts of said second relay.

5. A highly sensitive detection unit in accordance with claim 4, in which a. said test means comprises a thermal circuit breaker which is adapted to interrupt current upon overload or upon manual activation;

b. indicating bulb means are connected through normally closed contacts of said second relay to said alternating current source.

6. A highly sensitive detection unit in accordance with claim 1, further characterized in that a. said neon glow lamp means being provided with extreme sensitivity by the connection of said hot line lead to one side of said glow lamp means and by connection of a predetermined minimum capacitance to the sensitivity lead side of said lamp means.

7. A highly sensitive detection unit in accordance with claim 3, further characterized in that a. said threshold fine tuning means is tuned to accommodate the actuation of said alarm means by the detection of a triggering capacitance in the nature of a minimal low light source.

8. A highly sensitive detection unit in accordance with claim 3, further characterized in that a. at least one flasher means is connected in series with the coil of said second relay to energize the same automatically to reset or to recycle the unit after a predetermined short interval.

Claims

1. A highly sensitive electrical detection unit adapted to be finely tuned for triggering by proximity with an object having a predetermined minimum Capacitance, said unit including a. hot line lead means adapted to be connected to an alternating current source; b. potential load lead means having sensitivity lead means connected thereto; c. a self-contained module mounting in closely spaced relation neon glow lamp means and photo-conductive cell means; d. said neon glow lamp means being connected between said hot line lead means and said potential load lead means; e. alarm means associated with actuatable relay means; f. said actuatable relay means being connected in series with said photo-conductive cell means and a second current source, in a manner whereby predetermined triggering capacitance applied to said sensitivity lead means will increase the light output of said neon glow lamp means in said module thereby causing current flow through said photo-conductive cell means, said alarm means being actuated through said relay means; g. threshold fine tuning means for establishing a minimum triggering capacitance including a potentiometer and a variable capacitor connected between said hot line lead means and said potential load lead means to form a parallel circuit with said neon glow lamp means with reference to said predetermined triggering capacitance necessary to actuate said alarm means when said sensitivity lead means is proximate to said triggering capacitance.

2. A highly sensitive detection unit in accordance with claim 1, in which a. said second current source includes diode means rectifying the current from said alternating current source.

3. A highly sensitive detection unit in accordance with claim 2, in which a. said actuatable relay means includes a first relay having a coil and normal closed contacts and a second relay having a coil, contacts, and a holding circuit; b. the coil of said second relay being connected in series through the contacts of said first relay.

4. A highly sensitive detection unit in accordance with claim 3, further including a. current interrupting test means connected in series with the normally closed contacts of said first relay, the coil of said second relay, and said hot line lead in a manner whereby the activation of said test means drops out said second relay; b. said second relay having normally closed contacts which close on the dropping out of said second relay; c. said unit being activated through said normally closed contacts of said second relay.

5. A highly sensitive detection unit in accordance with claim 4, in which a. said test means comprises a thermal circuit breaker which is adapted to interrupt current upon overload or upon manual activation; b. indicating bulb means are connected through normally closed contacts of said second relay to said alternating current source.