US2590770A - Automatic fire alarm - Google Patents

Description

March 25, 1952 A. HIRSCHLE AUTOMATIC FIRE ALARM Filed April 4, 1950 IN VEN TOR.

M?) c b 0 ll/red Patented Mar. 25, 1952 UNITED STATES PATENT OFFICE AUTOMATIC FIRE ALARM Alfred Hirschle, Philadelphia, Pa.

Application April 4, 1950, Serial No. 153,811

12 Claims.

The present invention deals with automatic fire alarms and is concerned primarily with an alarm which is peculiarly adapted for installation where a concealed alarm is required.

At the present time there are many fire alarms which are installed about the particular premises to be protected and which alarms are electrically operated. Obviously should there be a power failure such alarms are not effective. With this condition in mind, the present invention has in View as one of its more important objects the provision of an automatic fire alarm which contains as a part of the alarm itself, a source of motive power for actuating the alarm. Thus, the operation of the alarm is not dependent on a current supply or other outside source.

While there have been proposed automatic fire alarms which are spring actuated, such alarms are. ordinarily effective for only a short period due to the limitations of spring actuation. Thus, if the alarm is not heard during this short period its purpose will be defeated.

With this condition in mind, a further highly important object of the invention is to pro-- vide an automatic fire alarm which includes a source of motive power which will be effective over a prolonged period so as to provide a period of operation of sufiicient extent to afford reasonably definite assurance that the alarm will be heard once it is set off.

A further highly important object of the invention is to provide an automatic fire alarm that is peculiarly adapted to be concealed in various home appliances, such as lamp bases, ceiling. light fixtures, ornamental door chime covers, and comparable places, and also for installation as auxiliary equipment for electrically operated alarm systems.

In carrying out the above noted objects, the automatic fire alarm of this invention avails of the principles of jet propulsion in providing the source of motive power. A rotor is provided in the form of an 8-shaped container of compressed gas and one end of this container takes the form of a frangible glass vial which when broken will release the gas and cause the rotor to rotate for a prolonged period. As a practical matter it has been found that these rotors may be designed to continue in operation for a period ranging from three to four minutes.

Another somewhat more detailed object of the invention is to provide, in an automatic fire alarm of the character indicated, a rotor which includes as an essential element a clapper in the form of a spring arm together with a fusible link for normally retaining the clapper in a retracted sprung position. This clapper is so positioned relative to the vial at the end of the gas container that when it is released by melting of the fusible link it will first strike the glass vial and break it to cause release of the gas and thereby start the rotor into rotation. The end of the clapper engages tabs or tangs which are formed on an enclosing bell to sound the alarm.

Various other more detailed objects and ad vantages of the invention such as arise in con nection with carrying out the above noted ideas in a practical embodiment will, in part become apparent, and in part be hereinafter stated as the description of the invention proceeds.

The invention, therefore, comprises an automatic fire alarm which consists essentially of a rotor that includes an S-shaped container for compressed gas having a frangible vial at one end and a clapper which is normally maintained in a retracted sprung position by a fusible link but which when released will fracture the vial and release the gas from the container to cause rotation of the rotor. A bell is disposed about this rotor and carries inwardly extending tabs which are struck by the clapper as the rotor rotates to cause the sounding of the alarm.

For a full and more complete understanding of the invention, reference may be had to the following description and accompanying drawing wherein:

Figure 1 is a top plan view with parts broken away and shown in section of an automatic fire alarm designed in accordance with the precepts of this invention; and

Figure 2 is a side view partially in section and partially in elevation of the alarm shown in Figure 1.

Referring now to the drawing wherein like reference characters denote corresponding parts, the automatic fire alarm of this invention is shown as being housed in a casing which is referred to in its entirety by the reference character C. The casing C comprises a bottom l0 having a downwardly extending peripheral flange H in the form of a bead which receives the lower edge of a cylindrical wall l2. The cylindrical wall l2 merges in with a top wall l3 that is integrally joined thereto.

Supported from the top wall l3 of the casing C is a bell which is identified in its entirety by the reference character B. The bell B comprises a top wall l4 having a central offset portion I5 which is secured to the top wall I3 of the casing C as by the rivet shown at l6. Integrally joined to this top wall I3 of the bell B is a cylindrical wall I! which it is noted is spaced from the wall l2 of the casing. Extending inwardly from this cylindrical wall I! at appropriately spaced intervals are a plurality of tabs i8 which preferably are struck from the bell and integrally connected thereto.

A rotor is referred to in its entirety by the reference character R. It includes a bracket [9 that is pivotally mounted as by a pivot pin 20 and bushing 2| on the bottom H) of the casing. This bracket includes a pair of spring arms 22 and 23 which partially encompass and securely grip a gas container 24. The latter is of the S-shape depicted in Figure 1 and may be made of any appropriate material, although the invention has particularly in mind the use of glass because of its frangible characteristics.

The container 24 is filled with gas under a required pressure and is sealed off at one end by the vial shown at 25. The vial25 is weakened at anappropriate point, preferably by the etchingshown at 26 so that when it is struckby the clapper about to be described, it will break off at 2 this-- point.

1 Formed as a part of the bracket l9 and integrally connected to the spring arm 23 is a clapper 21 which is formed with a ball 28 at its free end. This clapper is of exactly the proper lengthto cause the ball 28 to strike the tabs [8 when the rotor R rotates with the clapper in a released position.

'Normally detaining the clapper 21 in a retracted sprung position is a fusible loop 29. Thi: loop 29 encircles both the container 24 and th clapper'2l so as to hold the latter in the position illustrated in Figure 1. The loop 29 is made -from an appropriate material which will fuse at a certain predetermined temperature. Thus, ii the alarm is intended to be set off at one hundred thirty degrees Fahrenheit the fusible link 29 must be made of a material which will melt at one hundred thirty degrees Fahrenheit. Fusible U materials of this nature are well known and available to the public as such.

Operation One or more of the fire alarms above described willbe located at appropriate places in the particular premises to be protected. If a fire should start the moment the temperature at the location of any of these alarms reaches the melting point of the fusible loop 29, this link will fuse and release the clapper 21. The first thing this clapper does is to spring over into the broken line position of Figure 1 in which it engages the frangible vial 25 and breaks the latter off at the marking 26. The gas which is compressed in the container 24 is now released through the restricted opening provided by the vial and due to reaction therotor R begins to rotate under the now well accepted principles of jet propulsion. As the rotor B so rotates, the ball 28 at the endof the clapper 21 strikes the tabs 18 on the bell and causes the alarm to sound. Due to the springy nature of the clapper arm 21 the engagement of the ball with the tabs l8 offers but little resistance to this rotation. With the gas in the container 24 under a proper degree of compression, the rotor will rotate for a period ranging from three to four minutes.

After an alarm has once been sounded it is obvious that a container 24 may be replaced by a new one that is suitably charged with the compressed gas.

While a preferred specific embodiment of the invention is hereinbefore set forth, it is to be clearly understood that the invention is not to be limited to the exact materials, constructions, and mechanisms illustrated and described because various modifications of these details may be provided in putting the invention into practice within the purview of the appended claims.

What is claimed is:

1. In an automatic fire alarm, the combination of: a bell having a wall from which projects a tab, a pivotally mounted rotor including a clapper adapted to engage said tab to sound the bell, a container for gas under pressure included as a part. of said rotor for causing rotation thereof, and means releasing said gas from said container causing rotation of said rotor.

2. In an automatic fire alarm, the combination of: a bell having a wall from which projects a tab, a pivotally mounted rotor including a clapper adapted to engage said tab to sound the bell, a container for gas under pressure included as a part of said rotor for causing rotation thereof, said container being formed with a frangible glass vial at one end which when broken releases gas from the container to initiate rotation thereof, and means for breaking said glass vial to release said gas from said container causing rotation of said rotor.

3. In an automatic fire alarm, the combination of: a bell having a wall from which projects a tab, a pivotally mounted rotor including a clapper adapted to engage said tab to sound the bell, a container for gas under pressure included as a part of said rotor for causing rotation thereof, said container being formed with a frangible glass vial at one end which when broken releases gas from the container to initiate rotation thereof, and fusible means normally maintaining said clapper in a retracted sprung position with the glass vial positioned to be engaged by said clapper upon release thereof from said fusible means.

4. In an automatic fire alarm, av casing, a bell carried by said casing and including a circular wall from which extend inwardly a plurality of tabs, a rotor pivotally mounted in said casing, a clapper included as a part of said rotor and comprising a spring arm with a ball at the free end thereof adapted to strike against said tabs, an S-shaped container of=gas included as a part of said rotorand having a'frangible vial at one end, said vial being positioned to be engaged and fractured by said clapper when the latter is released, and a fusible loop normally encircling said clapper arm and said container to maintain said clapper in a retracted position.

5. In an automatic fire alarm, a casing, a bell carried by said casing-andincluding a circular wall from which extend inwardly a plurality of tabs, a bracket pivotally mounted centrally of said casing and including a pair of upwardly extending spring arms, ans-shaped container of gas grippingly engaged by said spring arms to be removably held thereby, a clapper arm extending outwardly from one of said spring arms and having a ball at its free end adapted to engage said tabs, and a fusible loop normally encircling a portion of said container and said arm to maintain said clapper in a retracted sprung position, said clapper being released upon the melting of said loop and adapted to break said containerto release said gas and cause movement of said container whereby said clapper is caused to be moved so as to engage said tabs and sound an alarm.

6. In an automatic fire alarm, a casing, a bell carried by said casing and including a circular wall from which extend inwardly a pluralit; of tabs, a bracket pivotally mounted centrally of said casing and including a pair of upwardly extending spring arms, an S-shaped container of gas grippingly engaged by said spring arms to be removably held thereby, a clapper arm extending outwardly from one of said spring arms and having a ball at its free end adapted to engage said tabs, and a fusible loop normally encircling a portion of said container in said arm to maintain said clapper in a retracted sprung position, said container being formed with a frangible vial at one end which is positioned to be engaged by said clapper upon release thereof to be fractured thereby.

7. In an automatic fire alarm, an alarm element and a container of gas adapted to be actuated by release of the gas to sound said alarm element.

8. In an automatic fire alarm, an alarm element, a rotor including a container of gas that is adapted to be rotated upon release of gas from said container, and means for causing rotation of said rotor to render said alarm element effective.

9. In an automatic fire alarm, a rotor cartridge comprising an S-shaped container of gas having a frangible vial at one end.

10. In an automatic fire alarm, a rotor cartridge comprising an s-shaped container of gas having a frangible vial at one end, said vial being formed with an etched mark whereby said vial will be fractured at said mark.

11. A fire alarm comprising a bell, a container containing gas under pressure movably supported adjacent said bell, a clapper secured to said container, and means releasing said gas from said container causing movement of said container and said clapper whereby said clapper is caused to strike said bell and sound an alarm.

12. A fire alarm comprising a bell, a container containing gas under pressure movably supported adjacent said bell, a clapper secured to said container, and means responsive to temperature releasing said gas from said container causing movement of said container and said clapper whereby said clapper is caused to strike said bell and sound an alarm.

ALFRED HIRSCHLE.

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

UNITED STATES PATENTS Number Name Date 1,047,706 Roberts et al Dec. 17, 1912 2,506,983 Williams u May 9, 1950

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