US2916730A

US2916730A - Alarm system

Info

Publication number: US2916730A
Application number: US552162A
Authority: US
Inventors: Jr Walter Johnson
Original assignee: Individual
Current assignee: Individual
Priority date: 1955-12-09
Filing date: 1955-12-09
Publication date: 1959-12-08
Anticipated expiration: 1976-12-08

Description

Dec. 8, 1959 w. JOHNSON, JR 2,916,730

ALARM SYSTEM Filed Dec. 9, 1955 2 Sheets-Sheet 1 INVENTOR.

AT TO QM EYS wAL-wen. JouufiON, An.

Dec. 8, 1959 w. JOHNSON, JR

ALARM SYSTEM Filed D90. 9, 1955 2 sheets -sheet 2 United States Patent ALARM SYSTEM Walter Johnson, Jr., Radnor, Pa.

Application December 9, 1955, Serial No. 552,162

2 Claims. (Cl. 340227) This invention relates to an improved alarm system having a central station at which the incidence of and the location of a fire or a burglary in progress is shown.

The primary object of the invention is to provide a simpler, more efficient, and more practical system of this kind having a single audible alarm signal and which combines in the system means for detecting and indicating the location of a fire, and means for detecting and indicating the location of an attempted burglary entrance of premises having a single audible alarm signal, means for detecting a fire and also means for detecting a burglary or attempted burglary.

Another object of the invention is to provide a system of this kind which is simple and reliable in 0,.era Lon, easy to maintain, repair and install, and which can be made in a rugged and serviceable form at relatively low cost.

Other important objects and advantageous features of the invention will be apparent from t. e following description and the accompanying drawing, wherein, for purposes of illustration only, a s ecific form of the invention is set forth in detail.

In the drawings:

Figure 1 is a perspective view of a signaling and annunciator unit, central station unit and a group of thermally actuated circuit closers associated therewith in accordance with the present invention;

Figure 2 is a vertical longitudinal sectional view taken substantially on the line 22 of Figure 1;

Figure 3 is a horizontal sectional view taken substantially on the line 33 of Figure 2; and

Figure 4 is a wiring diagram.

Referring to the drawings in detail, the illustrated system involves a central station unit 9 comprising an elongated rectangular cabinet 10 provided with a transparent cover 12 and with a partition 11 traversed by a row of electric annunciator bulbs 14, visible through the cover 12 along one side of the cabinet. A fire indicating bulb 16 and a burglary entrance indicating visual signal bulb 18 traverses the partition 11 near one end of the cabinet and are visible through the transparent cover 12. A pilot light bulb 2i) traverses the partition 11 and is visible through the transparent cover 12 to indicate that the system is in working order. The system includes thermally actuated circuit closers 22 which are located at selected stations within a structure and each comprises a middle or first contact 24, and outer or second and

third contacts

26 and 28, contained within a housing 29. These contacts are adapted to be bridged by a bridging contactor 30 which is conventionally actuated by any suitable thermally responsive element such as an expanding bellows 32. As many thermally responsive circuit closers 22 as there are annunciator lamps 14 are provided.

A suitable source of electrical energy such as a transformer 34 is mounted within the cabinet 10 and is connected by a conventional flexible cable 36 and connector plug 38 to a conventional current outlet. One side of the secondary of the transformer 34 is connected by a 2,916,730 Patented Dec. 8-, 1959 conductor 40 to ground while the remaining side is connected by a fuse 42 with one side of a manually actuated control switch 44 by means of which the alarm system may be connected to or disconnected from the transformer 34. The remaining side of the switch 44 is connected to one side of the pilot bulb 20, whose remaining side is grounded at 45 so that when the switch 44 is closed, the pilot lamp 20 will be illuminated and indicate an operative condition of the system. The side of the switch 44 that is connected to the pilot lamp 20 is con-. nected by a wire 47 to the middle contact 24 of each of the thermally responsive switches 22.

A manual testing switch 46 has one side thereof connected to the wire 47 and its other side connected to one side 48 of an audible signal 50, whose other side is grounded at 49. It will thus be seen that when the switch 46 is closed and the switch 44 is closed, the audible signal 50will be set into operation so that a test of the operativeness of the audible signal may be made by closing the switch 46 when the switch 44 is closed.

The third contact 28 of each thermal circuit closer 22 is connected by a wire 51 to one side of an annunciator bulb 14 while the remaining sides of these bulbs are grounded at 53, so that when a bridging contactor 30 is engaged with the

contacts

24, 26 and 28 under the influence of thermal expansion of the member 32, a ciruit will be closed through a related annunciator bulb 14 and will flow from the source 34 through the switch 44 and (ontact 24 through the contact 28 and thence through its respective annunciator bulb 14. The fire indicating bulb 16 has one side connected by wires 53 to the contacts 26 of all of the thermally actuated units 22 and its remaining side is grounded at 57 so that when a bridging contactor 30 engages the

contacts

24, 26 and 28, the fire indicating lamp 16 will be illuminated and indicate that a fire is in progress in a Zone indicated by an annunciator bulb 14.

Mounted at suitable stations throughout a building are pairs of

burglary contacts

52 and 54. The contacts 52 are connected to the middle contacts 24 of the thermal units 22 by wires 54 which are also connected to a wire 61 which is connected to the switch 44 and the transformer 34. The

contacts

52 and 54 are bridgeable by means of contactors 56 which are electrically connected together by a wire 63, and by

wires

65 and 67 to the terminal 48 of the audible signal 50, and to one side of the burglary indicating bulb 18, whose opposite side is grounded at 69. It will thus be seen that when any one of the manual contactors 56 is advanced into bridging contact with a pair of

contacts

52 and 54, the annunciator bulb 14 related thereto will be illuminated along with the burglary indicating bulb 18 and the audible signal 50.

It will be understood, of course, that the cabinet 10 is located at some central station where the sound produced by the audible signal 50 will arouse an attendant who, by glancing at the cabinet, will be able not only to locate the area in which the fire or burglary is in progress, but to readily detect whether it is a fire or a burglary by the illumination of either the visual signal bulb 16 or the visual signal bulb 18, and act accordingly.

By thus combining the visual fire or burglary indicating means with audible signal means, it will be obvious that but a minimum amount of wiring is required in order to completely protect a structure from the ravages of fire or burglary.

While in the foregoing there has been shown and described the preferred embodiment of this invention, it is to be understood that minor changes in the details of construction, combination and arrangement of parts may be resorted to without departing from the spirit and scope of the invention as claimed.

What is claimed is:

1. In a fire alarm system, a thermally actuated normally open switch adapted to be disposed at a selected station of a building, said switch including three fixed contacts arranged in aligned spaced relation and a thermally responsive contact movable into closing relation with all three of said fixed contacts simultaneously, a source of current, a first conductor means connecting one side of said source to one of said contacts, an audible signal, a second conductor means connecting said audible signal to another one of said contacts, a visual annunciator, a third conductor means connecting said annunciator to the remaining one of said contacts, a testing switch including a pair of terminals, a fourth conductor means connecting one of the terminals of said-testing switch to said first conductor means, a fifth conductor means connecting the other of the terminals of said testing switch to said visual annunciator, the other side of said source having a ground connection to said audible signal and said annunciator.

2. In a fire alarm system, a thermally actuated normally open switch adapted to be disposed at a selection station of a building, said switch including three fixed contacts arranged in aligned spaced relation and a thermally responsive contact movable into closing relation with respect to all of said three fixed contacts simultaneously, a source of current, a first conductor means connecting one side of said source to one of said contacts, an audible signal, a visual signal, a second conductor means connecting said audible and visual signals to another one of said contacts, a visual annunciator, a third conductor means connecting said annunciator to the remaining one of said contacts, a testing switch including a pair of terminals, a fourth conductor means connecting one of the terminals of said testing switch to said first conductor means, a fifth conductor means connecting the other of the terminals of said testing switch to said visual annunciator, the other side of said source having a ground connection to said visual signal, said audible signal, and said annunciator.

References Cited in the file of this patent UNITED STATES PATENTS 1,536,933 Rose May 5, 1925 1,996,308 Shyrock Apr. 2, 1935 2,074,262 Grant Mar. 16, 1937 2,599,623 Forrester June 10, 1952 2,624,792 Fruh Jan. 6, 1953