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Publication numberUS2552331 A
Publication typeGrant
Publication date8 May 1951
Filing date8 Sep 1947
Priority date8 Sep 1947
Publication numberUS 2552331 A, US 2552331A, US-A-2552331, US2552331 A, US2552331A
InventorsLamb Anthony H
Original AssigneeLamb Anthony H
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Electric clock fire alarm
US 2552331 A
Abstract  available in
Previous page
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Claims  available in
Description  (OCR text may contain errors)

y 8, 9 A. H. LAMB ELECTRIC CLOCK FIRE ALARM 2 Sheets-Sheet 1 Filed Sept. 8, 1947 y 1951 A. H. LAMB 2,552,331

ELECTRIC CLOCK FIRE ALARM Filed Sept. 8, 1947 2 Sheets-Sheet 2 INVE OR.

WA BY Patented May 8, 1951 UNITED STATES PATENT OFFICE 2,552,331 ELECTRIC CLOCK FIRE ALARM Anthony H. Lamb, Hillside, N. J. Application September 8, 1947, Serial No. 772,634

2 Claims. 1

This invention relates to fire alarm devices and more particularly to novel combinations of devices that include an audible sound producing member serving a primary function and provided with temperature responsive control means adapted to actuate the sound producing member when the temperature of the surrounding air reaches a predetermined value.

The appalling number of fatalities due to fire, especially in the home and hotels, is a matter of public record. As a result of our technical advances we have moved into our homes and buildings tremendous forces of potential destruction in the form of electricity, gas, heating devices, radio antennae, chemicals, cleaning fluids, etc. In view of these, and many other potential sources of fire, it is significant that a more general use is not made of safety devices.

With respect to loss of life, it is known the critical period of a fire is the first few minutes and the greatest number of fatalities occur as a result of fires starting in the night. In the majority of the cases victims find themselves trapped by fire because they were not aware of the danger until too late.

During the first few minutes of a fire there is a rapid generation of heat, smoke, and poisonous gases. Unfortunately, the poisonous gases permeate to other rooms in the building many minutes before a sharp rise in temperature and the inhalation of these gases does not immediately awaken a sleeping person with the result that upon finaly awakening the person is in a mental stupor and incapable of correct and decisive action.

It being a matter of record that the number of fire fatalities is directly related to the time elapsed between the actual start of the fire and a consciousness of the fires existence, the almost complete absence of fire alarm devices in homes and hotels is a matter worthy of investigation.

I am aware of the various, orthodox fire alarm devices and systems available at present. These have not found general and wide use in dwellings for various reasons such as the following:

1. The high cost of the device per'se.

2. High installation costs.

3. Unsightliness and damage to walls or woodwork caused by installation.

4. Intricate nature of device placing it beyond the confidence of the average user.

5. Complexity requiring a trained installer.

6. High maintenance costs.

At present there exist a wide variety of devices of unquestioned acceptance for use in the home 2 and which devices serve a primary purpose of producing an audible signal or sound at selected periods. Examples of such devices are radio sets, door signals, electrical and/or mechanical clocks, etc. In its broad aspect my invention contemplates the provision of devices of this type and including auxiliary, temperature actuated means adapted to cause operation of the signal or sound producing member when the temperature of the surrounding air reaches a predetermined value. The temperature actuated means does not in any way interfere with the normal operation of the device.

A broad object of this invention is the provision of a sound producing member serving a normal, primary purpose in combination with temperature actuated control means whereby the sound producing member serves the additional and complementary purpose of sounding an alarm when the temperature of the surrounding air reaches a predetermined value.

With respect to a radio receiving set the invention contemplates the provision of a temperature actuated switch associated with the volume control circuit of the radio. Closure of the switch causes the receiver to be turned on to full or unusually high volume thus blaring forth an unmistakable warning.

It is a specific object of this invention to provide a radio receiving set in combination with a temperature actuated switch whereby the receiver is turned on to high volume output when the temperature of the surrounding air reaches a predetermined value.

With respect to door signals the invention contemplates the provision of a temperature actuated switch establishing closure of the electrical circuit in parallel with the door button. The temperature actuated switch is normally open and may be placed. in the chime housing or in any other desired location being connected to the signal system by two wires. When the temperature of the air surrounding the temperature actuated switch reaches a predetermined value, the switch closes the electrical circuit to the signal. A plurality of temperature actuated switches may be employed each located in an area to be protected.

In the case of the conventional single stroke door chime additional time delay means are provided to cause periodic or recycling actuation of the signal once the temperature actuated switch is caused to close.

It is, therefore, an object of this invention to provide temperature actuated control means in combination with door signals whereby the door signal serves the additional and complementary purpose of sounding an alarm when the temperature of the surrounding air reaches a predetermined value.

With respect to clocks the invention contemplates the provision of a conventional alarm clock provided with auxiliary temperature actuated means adapted to sound the alarm upon a predetermined rise in the temperature of the air surrounding the clock. The addition of the temperature actuated means does not interfere with the normal, presettable alarm mechanism but once the temperature actuated means is set in operation the alarm continues to ring until reset by hand to condition the device for a subsequent cycle of operation.

An object of this invention is the provision of an alarm clock provided with auxiliary means adapted to sound an alarm when the temperature of the air reaches a predetermined value.

The above enumerated and other objects and advantages will be apparent from the following description when taken with the accompanying drawings illustrating various embodiments of the invention. The drawings are for purposes of illustration and are not to be construed as defining the scope or limits of the invention, reference being had for this purpose to the appended claims. i

In the drawings wherein like characters denote like parts in the several views:

Figure 1 is a central cross-sectional view showing a simple embodiment of a temperature actuated switch of the type contemplated by this invention;

Figure 2 is a diagram of the volume control circuit of a conventional radio receiving set;

Figure 3 is a circuit diagram showing a functional adaptation of a temperature actuated switch designed to operate the volume control of the type shown in Figure 2;

Figure 4 is a circuit diagram illustrating the combination of a single stroke door chime and a' temperature actuated switch of the recycling yp Figure 5 is a front view, in partial cross-section.

illustrating the adaptation of a temperature actuated deviceto a conventional electrical alarm clock.

be connected into an electrical circuit by solder ing wires 21 to the end thereof.

In the assembled unit, the blades 26, 2i normally are biased toward each other to establish good mechanical and electrical contact between the contact buttons 2B, 2!. However, the contact buttons are set in open circuit position by interposing a pellet 28 between the blades 20, 2| substantially as shown. The pellet 28 comprises a material that is solid at normal room temperature but which melts at a specific, elevated temperature dependent upon the particular material employed. Various wax compositions and metal alloys are suitable for this purpose.

For purposes of this description let it be as-.-

4 suined the pellet 28 comprises a compound having a melting point of 110 F. At temperatures below this value the pellet 23 is a solid and retains the contacts 2| in spaced-apart relationship. When a fire breaks out in the vicinity of the pellet the surrounding air temperature quickly exceeds 110 F. whereupon the pellet melts permitting closure between contacts Zil', 2i to establish an electrical circuit. It is apparent this construction provides a temperature actuated switch adapted to actuate various alarm or signal devices as will be described in more detail hereinbelow. Once the pellet 28 has melted the contacts 26', 2| remain closed until a new pellet is inserted between the switch blades. This is desirable to assure proper attention being given to the device itself and to conditions causing actuation thereof.

While I have thus far described a simple construction of the temperature actuated switch it is apparent the device is subject to a wide range of designs to meet specific requirements.

Referring now to Figure 2 there is shown a conventional volume control circuit of a radio receiving set comprising a potentiometer or volume control 29 connected across the audio input stage. The strength of the signal applied to the voice coil 36 of the loud speaker 34 is controlled by the voltage potential applied to the grid 32 01 the electron tube 33. Full volume out of the loud speaker is obtained by setting the slide contact 34 to the upper end of the potentiometer 29.

Figure 3 illustrates the application of my temperature actuated switch to the volume control circuit of Figure 2 to convert the receiver to a fire alarm. In this instance the switch comprises a series of metal blades, 35, '36, Bl, 38 and 39 provided with contact buttons 35a, 36a and 35b, Sia, 38a, and 39a respectively. Figure 3 is drawn to illustrate functional operation rather than mechanical details as multi-blade switch arrangements of this type are well known in the art. The temperature sensitive pellet 28 is shown interposed between the long blade 36 and a fixed surface ti). Under this condition the contacts 35a and 36a are closed and all other contacts are open.

The switch blades 35 and 36 are interposed into the circuit of the volume control by wires ll and 42 as shown. Inasmuch as the contacts 35a and 36a are normally closed, the slide contact 34 may be used in normal manner to control the volume of the receiver. However, when the temperature of the surrounding air reaches a predetermined value, as when a fire occurs in the room in which the radio receiver is located, the pellet 28 melts permitting blade 36 to move downward causing opening of the contacts 35a and 36a and closing of the contacts 36b and 31a. Under this condition the position of the slider 34 is immaterial as the full voltage is applied to the grid 32 through wire 43, blade 31, contact 3111, contact 3%, blade 36 and wire 42. As thus far described the set is immediately conditioned for full volume output from the loud speaker 3!. Therefore, it is apparent that if the radio set is in operation at any volume level, the full volume blast from the speaker will serve as a fire alarm.

Provision is also made to sound an alarm in this manner even though the radio set is turned off at the time of the fire. Electrical power is supplied to the radio from the power line by connecting the set to an electrical outlet by means of a plug 44 and duplex cord 45. Power to the power transformer 46 is controlled by an onoff switch 41, the radio being turned off when switch 41 is open. Connected in parallel with the switch 41 are blades 38 and 39 of the temperature actuated switch by means of wires 48 and 49. As shown in Figure 3 the contacts 38a and 39a are normally open when the solid pellet 28 is in position. Therefore, control of the radio is within the discretion of the user. When the pellet 28 melts contacts 38a and 39a close thereby turning the radio on. Simultaneous closure of contacts 361) and 31a cause full voltage to be applied to the grid of the tube. Thus, the loud speaker is caused to operate at maximum volume. The nature of the sounds emitted by the loud speaker are immaterial. Usually a radio set remains tuned to a given broadcasting station after it is turned off in the particular program at excessive volume will serve as a fire alarm. Even though the set is not tuned to a sending station wave length applicationof full volume across the speaker coil causesa series of loud vibrations and/or sqealing, etc.

The temperature actuated device may bepositioned within the cabinet of'the radioset at any point wherein the surrounding temperature is approximately the same as that of the. roomv air. Alternatively, the device may be mounted external of the cabinet in say, a recess provided for this purpose. T:

It will now be apparent my invention provides a novel combination of a radio receiver'adapted for normal use under normal conditions and serving the added function of an economical fire alarm.

Figure 4 illustrates my temperature actuated switch applied to a door chime. The door chime comprises a chime bar 50, and a striker 5| actuated by the solenoid 52 that is energized by low voltage current furnished by the transformer 53 when the electrical circuit is completed by closure of the door-button switch 54. The temperature actuated switch comprises the blades 55 and 56 carrying contacts 55a and 56a respectively said blades being spaced apart by the pellet 28 inserted between the blade 55 and a fixed surface 59, that may form the switch mounting plate. Alternatively the switch may take the form shown in Figure 1. The blade 55 is connected to one side of the transformer 53 by wire 51 while the blade 56 is connected by wires 63 to a fixed blade 58 of a time delay relay T. The other elements of the time delay relay comprise a bimetallic strip 66 having a heater winding 6| thereon, one end of said winding being electrically connected directly to the bimetallic strip 60 and the other end of the winding being connected to the solenoid 52 by the wire 62. Each of the blades 58 and 60 carries a contact 58a and 60a.

When the device is connected as shown in Figure 4 the door chime may be operated in the normal manner, that is, every closure of the door switch 54 causes the solenoid 52 to be energized thereby attracting the striker 5| to strike the chime bar 50. In case of a fire in the vicinity of the pellet 28 the rapid increase in air temperature causes the pellet to melt. When this occurs the blade 55 springs toward the blade 56 and contacts 55a and 56a close. Closure of contacts 55a and 55a completes an electrical circuit between solenoid 52 and the transformer 53 as follows: wire 51, contact 55a, contact 56a, wire 63, contact 58a, contact 60a, winding 6|, wire 62, solenoid 52, and wire 64. This causes the striker 5| to strike the chime bar 50. Although the contacts 55a and 56a of the temperature actuated switch remain closed, the contacts 58a and 60a of the bimetallic relay T eventually open due to the heat generated by the current flowing through the heater winding 6|, as is well known in the art. Upon opening of the contacts 58a and 6011 the circuit to the solenoid 52 is broken permitting the striker 5| to drop back to its normal position and at the same time removal of current fiow through the heater winding 6| permits cooling of the bimetallic strip 66. Upon cooling, the bimetallic strip 60 moves toward the fixed blade 58 causing closure of the contacts 58a and 66a to thereby again complete the electrical circuit and cause a second sounding of the chime. By proper design of the heater winding 6| and the solenoid 52 the' recycling period of the circuit can be made relative short thereby causing a rapid actuation of the chime to serve as a fire warning. It is apparent several temperature actuated switches of the type described can be connected to a single door chime, each switch located in a section or room of a structure to serve as a guardian instantly ready to sound an alarm should fire break out in such location.

While I have described this particular embodiment of the invention with reference to a single stroke door chime itis apparent the same considerations hold with respect to a conventional door bell or buzzer. Also, the invention is equally adapted for use with the various motor driven multiple chime devices.

Figure 5 illustrates an electrical alarm clock in combination with a temperature actuated control. In clocks of this type the alarm sounding member usually comprises a fiat strip of softiron fastened or pivoted at one end and disposed adjacent to the field structure of the driving motor. Normally, the soft-iron strip is held somewhat away from the motor field structure by mechanical means associated with the settable alarm mechanism. At the pre-set time the alarm mechanism removes the obstruction in the path of the soft-iron strip whereby the strip is magnetically attracted to the field structure of the motor. As clocks of this type operate on alternating current and as the soft-iron strip is fastened on one end, the strip vibrates rapidly against the motor field structure producing a loud, buzzer-type noise.

A clock made in accordance with this embodiment of the invention is provided with an auxiliary soft-iron strip 65 secured on one end by a rivet 66 to the case 61. The strip 65 extends through an opening in the case and lies adjacent to the field structure 68 of the driving motor. The temperature sensitive pellet 28 is inserted bteween the soft-iron strip 65 and a bracket 69 secured to the exterior of the case 5?, substantially as shown. As long as the pellet 28 remains a solid the strip 65 remains motionless. When the pellet 28 melts the strip 65 is attracted magnetically to the field structure and vibrates in the same manner as the conventional electrical alarm.

It is is now apparent my invention provides a unique new combination adapted to serve the normal, primary purpose of a pre-settable alarm clock and including simple yet positive means for sounding an alarm should fire break out in the room in which the clock is located.

Having described the invention as related to an electrical alarm clock in which the temperature actuated alarm comprises an auxiliary alarm member I do not intend that the invention be limited in this respect. It is apparent the Figure construction is applicable to simple clocks that do not include a normal, pre-settable alarm. Also, the temperature control element is adapted for use with mechanical alarm clocks in which case the melting of the pellet 28 produces a mechanical motion to free the clapper of such alarm clocks.

Having now illustrated and described several embodiments of my invention, variations and modifications in the construction and arrangement of the parts will become apparent to those skilled in the art without departing from the spirit and scope of the invention as set forth in the appended claims.

Although the pellet type, temperature actuated switch is preferred other well known temperature sensitive devices such as a bimetallic switch, fusible wire switch, resistance device, etc., can be employed in practising the broad aspects of the invention.

So far as I am aware it is broadly new to provide a combination device comprising a household sound producing member serving regularly a primary purpose and including a temperature actuated device adapted to actuate said sound producing member when the temperature of the surrounding air reaches a predetermined value.

I claim:

1. An electric clock of the type wherein an audible alarm is produced by a soft-iron member that vibrates against the field structure of the .motor when the motor is energized, characterized by the fact that the soft-iron member is spaced from the said field structure in nonvibrating position by a temperature sensitive member which changes from a solid to a fluid at a predetermined temperature above normal room temperature.

2. The invention as recited in claim 1, wherein the temperature sensitive medium is disposed external with respect to the clock housing.


REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 471,929 Wooley Mar. 29, 1892 1,011,175 Egan Dec. 12, 1911 1,198,220 Hein Sept. 12, 1916 1,795,507 Riccio Mar. 10, 1931 1,849,551 Praturlon Mar. 15, 1932 1,955,558 Nelson et al Apr. 17, 1934 2,069,622 Perlman Feb. 2, 1937 2,147,718 Siddall et al. Feb. 21, 1939 2,318,005 McGuinness May 4, 1943 2,367,639 Conboy Jan. 16, 1945 2,411,752 Padilla Nov. 26, 1946 2,417,254 Kelly Mar. 11, 1947

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Referenced by
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US2611810 *18 Feb 195023 Sep 1952Leonard M GreeneAirplane warning system
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U.S. Classification340/590, 340/691.1, 368/12, 340/594, 340/328
International ClassificationG08B17/06
Cooperative ClassificationG08B17/06
European ClassificationG08B17/06