US2721239A - Burglar alarm - Google Patents

Description

Oct. 18, 1955 w. KUFFER 2,721,239

BURGLAR ALARM Filed June 2, 1954 2 Sheets-Sheet l Fig. 3

Will y lfuffer K /2 INVENTOR.

Fig. 4 BY wwdi Aff'y.

Oct. 18, 1955 W. KUFFER 2,721,239

BURGLAR ALARM Filed June 2, 1954 2 Sheets-Sheet 2 M'll y Ira/fer INVENTOR. h-

United States Patent BURGLAR ALARM Willy Kufter, Englewood, N. J. Application June 2, 1954, Serial No. 433,870

1 Claim. (Cl. 20061.62)

This invention relates to improvements in burglar alarms for private homes and stores and, specifically, it refers to a simple battery operated alarm which can be installed in doors and windows at low cost.

The most frequently used types of burglar alarms utilize conductors which are placed across windows and doors which are to be protected and which are broken when an unauthorized person opens or shatters same. Such alarm systems are impractical and undesirable in homes because of the fact that it is not possible to hide the wiring and the breakable conductors which are applied usually in the form of tape on windows, etc. For this reason burglar alarms have not become popular in the average home. In my present invention I have eliminated this difiiculty and I have produced a simple and effective burglar alarm which may be installed with hidden wiring and which is entirely invisible inside or outside the house.

The main object of my invention is to provide a simple and eifective burglar alarm which may be easily installed in doors and windows in concealed fashion so that the installation will not deface nor obstruct the normal use of doors and windows.

Another object of my invention is to provide a burglar alarm which can be manufactured and installed at very low cost.

Still another object of my invention is to provide a burglar alarm which can be concealed completely and where even the actuating means are hidden from unauthorized tampering.

Other objects and advantages of my invention will be apparent during the course of the following description and claim.

In the accompanying drawings forming a part of this specification, and in which like numerals are employed to designate like parts throughout the same,

Figure 1 is a section of a switch embodying part of my invention taken along line 1-1 in Figure 2,

Figure 2 is a section taken along line 2--2 in Figure 1,

Figure 3 is a partial elevation and section of a door illustrating the installation of my invention,

Figure 4 represents the circuit diagram of my burglar alarm,

Figure 5 represents a partial enlarged elevation of installation of my invention in a door frame,

Figure 6 is a section taken along line 66 in Figure 5,

Figure 7 is another enlarged partial elevation of an installtion of a master switch in a door frame.

Figure 8 represents a section taken along line 88 in Figure 7,

Figure 9 is a section taken along line 9-9 in Figure 10, and,

Figure 10 is a section taken along line 1010 in Figure 9.

In the drawings wherein for the purpose of illustration is shown a preferred embodiment of my invention, the basic system is best illustrated by the simple wiring diagram in Figure 4. The alarm consists of a battery 10 connected to an alarm 11, a master switch 12 and a standard alarm switch 13. In the simple system illustrated in Figure 4, the switches 12 and 13 may be installed in two doors or in a door and a window. The standard switch 13 is illustrated in detail in Figures 1 and 2 and consists of a housing 14 having a removable cover 15 and mounting ears 16 and 17. In the housing 14 is mounted a simple jack switch having two conducting springs 18 and 19 each of which may have a little silver point 20 at the contact end. The other ends 21 and 22 of said springs are punched out as soldering lugs for the connection to the wiring. The springs 18 and 19 are mounted by means of two insulator screws 23 and the insulating spacers 24 and 25. An actuating lever or trigger 26 is pivoted on the side 27 and has a nose 28 which engages a detent spring 29 which is fastened to the housing 14. A trigger push rod 30 extends through a bushing 31 and housing 14 and is engaged in operatable relation with a nose 28 on trigger 26.

The standard alarm switch as illustrated in Figure l is normally opened as illustrated. The nose 28 of the trigger 26 is engaged on one side of a bump on the spring 29 thus holding same in its open position. The two springs 18 and 19 are separated in a normal open position. The trigger push rod 30 requires only a slight pressure to push the nose 28 over the bump on spring 29 and the action of spring 29 will then snap said nose 28 into engagement with spring 18 pushing same against spring 19 thereby closing the circuit.

The trigger push rod 30 can be made of any desirable length and is placed through a small hole in the door frame or window frame and the other end of same is adjusted in length so as to be engageable with the door or window when the same are open. This is illustrated in Figures 5, 7, and 8. When the door is closed as shown in Figure 8 the end of the rod 30 rests in a small recess in the door proper. When the door is opened, the end of rod 30 will be pushed in toward the trigger 26 and will actuate same.

In such cases as above mentioned the standard switch with housing 14 is placed in a suitable recess in the frame of the door as illustrated in Figures 3, 5, 6, 7, and 8. As shown in Figure 3, the switch may either be placed above the door or below same. Where the alarm is installed in already existing buildings, it usuaily is possible to remove the trim and to chip out a space behind same and the wiring is then placed under the trim and should be completely concealed. This is possible due to the fact that only low battery voltage is used which cannot be of any safety hazard due to short circuits.

In other cases it may be desirable to protect an area inside of a door or on a stairway. In this case a thin movable tread 32 is mounted on springs 33 under the carpet 34 and is thus not visible for the uninitiated. The tread 32 is spaced slightly away from the normal floor or stair tread 35, see Figures 9 and 10, so that when a person steps on the concealed tread 32 same will move down slightly and entirely unnoticed by the intruder, will actuate the alarm switch, similarly to the previously described applications. In this case the rod 39 extends up through the floor or tread 35 and is normally in contact with the loose tread 32 and is movable with same to actuate the alarm switch.

On most alarm installations it is desirable to have a master switch which is turned on with a key on the outside of the door to be protected. It is to be understood that while the smallest installation may be only two doors, or one door and one window, my system is of such flexibility that it can be extended to include many doors and many windows when desired. In all such cases, however,

there will have to be one master switch where the whole thing is turned on when the operator wants the protection on. If there are several doors and windows, the alarm switches are so arranged that they are always in operating condition and will be ready to give alarm as soon as the current is turned on after the doors and windows have been closed. The turning on of the protective system, therefore, can be done at one point, for instance, with a key in a lock as indicated in Figures 5, 6, 7, and 8. The lock 30 is installed on the outside of the door jarnb 37 and extending through same as indicated in the figures mentioned. The lock 36 may be an ordinary door lock and may be arranged to use the same key as used in the door. The tang 38 of the lock extends through the door jamb 37 and carries a small arm 39 on its inner end. This arm 39 is arranged in such relation to the trigger 26 that when the key is placed in lock 36 and turned, the arm 39 will move and will place the same in its operating position ready to give alarm when the door is opened.

In addition to the two mentioned switches there also may be another on-ofi. switch for turning on and off the battery power. This switch, however, is carefully hidden so that no intruder would find .same.

The operation of my invention has been described in detail above but may be summarized as follows:

When a householder decides to put on the alarm, the inside on-off switch is turned on after the proper doors and windows have been shut and thus have rods 30 in operating relation to the triggers 26 of the various alarm switches installed. If an outer door is protected, it may he turned into operating condition with a key as shown in Figures 58 inclusive. After thus putting the protective system into operation, any unauthorized opening of doors or windows thus protected will close the protective circuit and will start 011 the alarm 11 which is preferably mounted on the roof or some other inaccessible place where it may easily be heard by neighbors and police etc.

When the householder decides to remove the protection, it is only necessary to turn ofi the main switch thus disconnecting the battery and putting the protection out of commission.

It is to be understood that the form of my invention, herewith shown and described, is to be taken as a preferred example of the same and that various changes in the shape, size and arrangement of parts may be resorted to, without departing from the spirit of my invention or the scope of the subjoined claim.

Having thus described my invention I claim:

In a protective system of the character described, the combination of an on-ofi switch and alarm switch in one unit, said switch being concealed in a door jamb and comprising a double ended, snap action trigger, one end of which protrudes on the outside of said switch; a loose push rod of small diameter concealed in said door jamb and extending through same with one end in operable connection with the inside end of said trigger and the other end protruding from said door jamb sufficiently to be operated when the door is opened; a lock placed in said door jamb adjacent to said switch, and an arm fastened with one end on the tang of said lock with the other end in operable connection with the outside end of said trigger, whereby said switch may be reset by turning the key in said lock.

References Cited in the tile of this patent UNITED STATES PATENTS 1,401,652 Scully Dec. 27, 1921 1,556,282 Bradey Oct. 6, 1925 1,786,098 Thon Dec. 23, 1930 1,915,239 Potter et al June 20, 1933 2,314,465 Shaw Mar. 23, 1943 2,617,868 Menkin Nov. 11, 1952 2,675,439 Merchant Apr. 13, 1954

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