US2870434A - Detection and signaling apparatus - Google Patents

Description

Jan. 20, 1959 G. R. SCHULZE DETECTION AND SIGNALING APPARATUS Filed Jan. 18, 1955 llllll 20 INDICATOR v LIGHT 33 1/ 22 ZONE! 1K l0 r k INVENTOR.

GEORGE R. SCH ULZE ByghWj/QW ATTORNEY panel.

United States Patent Q DETECTION AND SIGNALING APPARATUS ,George R Sehulze, Hopkins, Minn, assignor to Minneapolisl-Ioneywell Regulator Company, Minneapolis, Minn, a corporation of Delaware Application Ja uary 1 eriatN 48 6 51Claims. (Cl. 340-427 The present invention is'concerned with a fire detection and alarm system for residential use, in particular,

an alarm means having a plurality of detectors connected thereto so that when anyone of the detectors senses .the presence of a fire in its locality a visible and audible alarm is given.

While fire detection systems are broadly old 'there is a market for an inexpensive andreliable system for use particularly in newly constructed homes. The present invention provides for a system which is dependable and can be periodically checked to determine whether .the alarm device is in working order. The system has a plurality of individual series circuits so :that one circuit can be used for each particular zone of the dwelling. In each circuit, for indicating the trouble in that particular zone, an indicator light is used so that if a fire occurs in one zone it will be so indicated on the main control A switch is provided in each zone for testing the particular zone by opening the detector circuit to energize both the alarm and the indicator.

It is therefore an object of the present invention to provide an. improved detection system.

A further object ,of the present invention is to provide an improved fire detection and alarm system having a plurality of branches each containing an indicator responsive to the detection of a fire in the locality of the branch.

Another object of the present invention is to provide in a detection system a responsive element having a sensing unit adapted to be mounted on a ceiling or surface, the sensing unit having an inverted cup-shaped cover being slightly spaced from the ceiling or surface when attached to the sensing unit.

These and other objects will become apparent upon a reading of the following specification and drawings of which:

Figure 1 is a schematic-drawing of the circuit and as sociated components of the fire detection system;

Figure 2 is an assembly view of one of the detector elements showing the clip for mounting it on a ceiling, the thermal sensitive unit, and the cover;

Figure 3 is a vertical view of the sensor element shown in Figure 2;

Figure 4 discloses the method of mounting the detector unit as assembled to a, surface or ceiling with the connection wires leading therefrom.

.Referring to Figure lean actuator 10 is shown having a core member 11 with an energization winding 14 wrapped thereon. A movable member 20 pivotally connected to member 11 at 21 isbiased counterclockwise awayfrom engagement with member 11 by a spring 22. Whenever the winding 14 is energized the magnetic flux produced in member 11 causes movable member 2! to pull against member 11 at the end opposite the pivotal connection to form a closed magnetic path.

Connected to the winding 14 is a series circuit containing a secondary winding 12, of a power transformer 13 connected to a source of power, and a plurality of indicator lights 33, 34, and 35 each of which by itself or all together is a sufficient resistance to reduce the current to winding 14 to cause member 20 to drop away from member 11. Connected in parallel with each of the indicator lights is a circuit comprising a normally closed switch 40 and a plurality of detectors or sensing elements 41. The switch is spring biased in a closed position and has a manual button for opening the circuit for test purposes.

Connected to member 20 and electrically insulated therefrom is a bell clapper 23 for striking an associated bell 24 when winding 14 .is de-energized and member 20 moves to the right. Clapper 23 is connected by a flexible conductor 30 to the upper end of winding 14. The bell frame is electrically grounded, as well as the lower side of secondary 12. Whenever anyone or all of the series circuits including detectors 41 are open and the current through one or all of the-lights, 33, 34 or 35 is not sufiicient to hold member 20 in, it will move to the right to cause clapper 23 to strike bell 24. This closes a shunt circuit to energized winding 14 which will again cause member 20 to pull in, resulting in a successive hammering of bell 24 by clapper 23. The clapper and bell actually perform a switching function.

As shown the circuit connected in parallel with the indicator lights is available for one particular zone thus with the lights 33, 34 and 35 a three-zone system might be obtained. To test any particular zone, switch 4% is opened and the indicator light for that particular zone is energized. At the same time the high resistance of the indicator light causes the actuator 10 to ring alarm bell 24.

Referring to Figure 2, one of detector units 41 .is shown having a disc shaped clip unit 50 having a plurality of projections 51 mounted in a circle on one side of the disc and adapted to be received into one end'of a cylindrical insulator 52. A screw 53 inserted through a hole in the center of the disc shaped unit is used to mount it to a surface such as the ceiling of the dwelling.

Mounted on member 52 with associated screws 56 is a pair of resilient members 54 and 55 joined by a low melting point alloy so that upon the temperature of the alloy reaching some predetermined value members 54 and 55 will spring apart. Obviously while members 54 and 55 are shown butted together such a fusible leakage could be made by overlapping them. A pair f ass iated term nal screws 61 and 62 for connecting lead wires to members 54 and 55 are inserted into insulater 52. A cover 64 having a disc shape, such as the shape of a portion of a hollow right angled inverted cone, has an upwardly curved bottom and an open top having a diameter larger than the bottom. A second disc shaped cli unit 65, substantially the same as 50, is attached to the bottom of cover 64 so that its projections are adapted to be received into the other open end of member 52. Thus, when assembled the detector unit is substantially as shown in Figure 4 with the leads and 71 connected to the terminal screws and the top of the cover 64 slightly spaced from the ceiling or a surface 72 upon which it is mounted.

Operation 40 is opened to simulate an open detector unit 41. This takes the shunt or parallel circuit away fromthe indicator light and its resistance when placed in the winding circuit is sufiicient to render itineffective in holding member 29 to the left. Member 20 is then dropped out and clapper 23 rings the bell. Upon testing any particular zone the light for that zone as well as the alarm is energized.

Assume that one detector unit 41 opened when'the temperature of the unit reached some predetermined value and the alloy 60 melted and members 54 and 55 sprung. apart. The indicator light for the particular zone having the open detector unit would be energized and actuator 10 would render an alarm.

While not shown the actuator 10, indicator lights 33, 34, and 35 and test switches 40 are mounted in a unit and the wires to the particular zones are strung therefrom to connect to the detector units 41'. Whenever an alarm occurs it is thus possible to determine what zone has caused the alarmas its associated indicator light would be energized.

Such a system is relatively simple to install in newly constructed homes and while some difiiculty might be experienced in placing it in existing homes, for the most part it could be installed with little effort. For each zone only a series circuit need be used, the detector units 41 being placed in different localities in that zone. For example, the two wires arestrung in the ceiling and stuck through the plaster at the center of the room. Clip of the detector unit is then fastened to the ceiling,

jby associated screw 53, close to the locality where the wires protrude. The insulator 52 having a sensing unit which is connected by screws 61 and 62 to the wires is then snapped onto the clip and the cover installed. With I such an assembly the detector unit is relatively obscure as the cover normally would be painted the color of the ceiling. As the cover is spaced slightly from the ceiling adequate circulation of air around members 54 and 55 is obtained so that their junction by the low melting point alloy is definitely susceptible to the presence of an extreme heat in that locality. With such a detector unit 41, replacement of the element is rather simple and can normally be done by the home owner should one become open or defective.

While the detection and alarm system is disclosed as being applied to fire detection it is obvious that any sort of condition detection might be obtained, therefore it is intended that the invention only be limited by the scope of the appended claims in which I claim:

1. In a fire detection and alarm system, actuator means having a bell clapper for energizing a bell, a' source of power, control circuit means connecting said source of power and said actuator means in series, said control circuit comprising a plurality of indicator lamps each of which is shunted by a series circuit comprising a test switch and a plurality of normally closed temperature responsive means adapted to open upon reaching a predetermined temperature, and another circuit means closed when said clapper engages said bell for shunting said control circuit to connect said actuator directly to said source so that when said control circuit is ineffective to maintain said actuator means energized said clap-per will successively engage said hell.

2. In a fire detection system, alarm means having a pair of terminals to which a detector circuit is connected, said alarm means responding to an increase in circuit resistance above a predetermined value, said circuit comprising a plurality of indicator means each of which is shunted by a plurality of normally closed detector means connected in series, said detector means comprising a cylindrical shaped insulating member having a pair of resilient members mounted on its outer surface, said resilient member being held together by a low melting point alloy, clip means adapted to be mounted to the ceiling, said clip means being received into one end of said cylindrical shaped member, anda cover adapted to be clipped to the other end of said cylindrical shaped member.

3. In a fire detection system having a plurality of detectors each comprising, a hollow cylindrical shaped insulator having a pair of resilient members fastened to its outer periphery, said members being soldered together at one end thereof by a low melting point alloy to form an electrical contact thus upon said alloy reaching a predetermined temperature said members spring apart opening said contact, clip means adapted to be received by one open end of-said insulator for mounting said insulator in a position to be responsive to the presence of a fire, and cover means adapted to be received by the other end of said insulator, said cover having a cup shape with a relatively fiat bottom and outwardly sloping sides so that its upper diameter is slightly greater than the insulator means, condition responsive means mounted on said insulator means, clip means having a plurality of resilient means adapted to be received in one end of said insulator means for mounting said insulator means to a surface, shield means having a portion adapted to be received in the other end of said insulator means, said shield means having a cup shape so that upon said clip means being mounted on the surface said insulator means is substantially protected by said shield means.

5. In a detection and alarm system, a source of power,

' actuator means adapted to pull a spring loaded bell clapper away from the engagement of a bell, first circuit means connecting said actuator means and said source in series to energize said actuator and pull the clapper away from the bell, a plurality of high resistance indicator means, said circuit means comprising said high resistance indicator means, a plurality of condition detection means having a low resistance when a normal condition is sensed, means connecting at least one of said detection means in parallel with each of said indicator means to form a low resistance circuit to maintain energization of such actuator means, and second low resistance circuit means formed when the clapper engages the bell, said second circuit means connecting said actuator means directly to said source so that when said first circuit has a "high resistance said actuator means is energized to cause the clapper to ring the bell.

References Cited in the file of this patent

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