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Publication numberUS1265361 A
Publication typeGrant
Publication dateMay 7, 1918
Filing dateMay 29, 1916
Priority dateMay 29, 1916
Publication numberUS 1265361 A, US 1265361A, US-A-1265361, US1265361 A, US1265361A
InventorsEmil Muringer
Original AssigneeEmil Muringer
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
US 1265361 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)


Patented May 7,1918.

nue'nfoz from the left,



Specification of Letters Patent.

Patented May 7, 1918.

Application filed May 29, 1916. Serial No. 100,507.

. To all whom it may concern:

Be it known that. l, EMTL Munnvonn, a citizen of the United States. residing at the borough of Manhattan. in the county of New York and State of New York, have invented certain new and useful Improvements in Burglar-Alarms, of which the following is a specification, reference being had therein to the accompanying drawings, forming part thereof.

1 y invention relates to burglar alarms of the electrical type and relates more particularly to burglar alarms which are combined with a usual form of lock. Objects of my invention are simplicity of construction, inexpensiveness of manufacture. effectiveness in operation, convenience and inexpensiveness of installation; reliability, durability and other objects and advantages which will hereinafter appear.

invention includes an automatically returning contact member, such as a' resilient cont-act plate combined with the keeper for a lock bolt in such a way as to be supported by the keeper out of electrical connection therewith and adapted to be pressed into contact therewith by transverse movement of the bolt relatively to the keeper in a direction for forcing the lock. Myinvention also includes features of construction and combinations of parts as will appear from the following description. j v

I shall now describe the electrical burglar alarm illustrated in the'accompanyin drawings embodying my invention an shall thereafter'point out my invention inclaims.

Figure 1 is an elevation ofa ortionof a door showing thereon a door-lock of the night-latch type having the electrical burgl'ar claim of m invention combined therewith, the'electrical circuit being shown-diagrammatically. I 1 1 Fig. 2 is a horizontal transversesecti'on on planes indicated by theline 2 2of Fig.

1 as viewed from above, the lock appearing in plan. a a r Fig. 3 is a vertical section on aplane indicated by the line 3-3 of Figs. 1 and 2 as viewed from the left. Fig. 4 is an enlarged view similar to Fig. 3, partly inelevation and partly. in vertical section on a plane indicated by the line4-4 of F ig. 5 as viewed from the right. 5

Fig. 5 is a vertical section on a plane indicated by the line 5 5 of Fig.4 as yiewed wit Fig. 6 is 'a transverse horizontal section on a plane indicated by the line 66 of Figs. 4 and 5 as viewed from above.

In the accompanying drawings the elec trical burglar alarm of my invention is shown as embodied in and combined with a snap lock of the type known as a night latch having a casing 1, a bolt 2, a handle knob 3 and a keeper 4 for the bolt 2 .the lock casing 1 being shown as secured in a usual way by screws upon a door 5, and the keeper 4 for the bolt 2 is shown'as similarly secured upon the door frame 6. The door lock, having the casing 1, the bolt and the handle knob 3, may be of a usual or of any suitable construction, and likewise-the keeper 4 for the lock bolt 2 may be of a. usual construction. but preferably, and as is shown in the drawings, is somewhat wider or deeper from left to right or laterally as to its bolt-receiving cavity or son that will presently appear.

A thin resilient metal contact plate 7 is carried by the keeper 4 and is supported at the inside thereof in slightly'spaced relarecess, for a reaforward wall of the keeper 4. These screws w 8 and 9 pass also through an interposed strip 10 of insulating material whichboth insulates the contact plate 7 from the metal keeper 4 and also spaces it the'refromin its outer or forward portion which projects freely in spaced relation to the inner' surface of the frontl wallfof the keeper as clearly appears inthe'drawings, particularly in Figs. 2, 3 and 6; The screws B end 9 are insulated from'the resilient contact plate 7 by means'of small collars 11 and washers 12 beneath thelieads of the-screws an the inside of the keeper 4'.' g I I The face off the keeper '4 adjacent'to the lock casing lisprovi ed,ja's shown, with a bolt-receivmg-openin -13-for the reception of the end of'the loc *bolt 2-in its locked position, and the'contact plate 7, at its outer edge, projects into this bolt openm 13 and is eferably,

the adjacent face of the keeper, as clearly appears in Figs. 2, 5 and of the drawings. The length or vertical dimension of the contact plate 7-"is shown as nearly equal to that asshown, Substantia ly flush which it projects, and the width or lateral dimension of the contact plate 7 is quite or to some extent greater than the distance to which the bolt 2 projects into the keeper 4. The contact plate 7 extends laterally from the outer face of the keeper 4 adj acent to the lock casing 1 inward substantially to the rear wall of the keeper, which is spaced back to provide a recess oi more than usual width, as hereinbcfore mentioned, so that a free resilient overhanging or unsupported portion of the contact late 7 is provided of considerable width an of a width substantially greater than the extent to which the lock bolt 2 projects into the keeper 4, as clearly appears in the drawings.

Pressure applied upon the outside of the door 5, such as would result from an at tempt to force the lock, or pressure applied u on the locking end of the lock bolt '2 or directly upon the contact plate 7, such as would result from the insertion from the outside of the door of a knife blade or the like with the intention of pushing back the lock bolt 2, will in each instance force or press the overhanging free outer margin of the contact plate 7 into contact with the adjacent inner surface of the forward wall of the keeper 4, thereby closing an electrical circuit for giving an alarm, as will now be described. 1

At one end, shown as the lower end, and adjacent to its inner edge opposite the lower retaining screw 8, the thin resilient metal contact piece 7 is provided with an extension 14 shown as projecting downwardly and rearwardly, as viewed from the inside of the door 5, within the keeper 4for forming an electrical connection to the contact plate 7. The upper retaining screw 9 which is proportionately longer than the 1 lower screw 8, holds in place a connecting strip 15 which projects within the keeper 4 upw arglly and rearwardly and which, through the retaining screw 9, is in electrical connection with the metal keeper 4, but is insulated from the contact strip 7 ,by means of thecollar 11 and war her 12 ofthe screw 9,asclearly app ars int-Fig. 4 of the drawings, the connecting strip 15 thusprovidinjgmeans for forming a electrical connection ito th e keeper 4. .:The projecting'free ends ofi the extension 14 and of theconnectingstrip 15 are providediwith binding posts 16; erg conveniently connecting electrical conductors thereto. It is to be noted that the-insulating strip 10, which spaces and alsdinsulates the contactplate 7 from the keeper 4, is extended at its ends so, as to assure that noeontact, can take place between the conductive extension 14 or connecting strip 15,tor the,,1binding 1:6 carriedgthere'by, and the adjacent wall ofthe keeper 4. i a

"The keeper 4 and contact plate ,7 are adapted'to' be connected in all-electricalcircuit including a source of electrical energy, such as a battery 17, and a translating device for giving an alarm, such as an electric bell 18. This circuit includes connecting conductors 19, 20 and 21, of which the conductor 19 is shown as connected to the binding post '16 of the extension 14 from the contact plate 7 and to the battery 17, the conductor 20 forms a connection between the battery 17 and the bell 18, and the remain, ing conductor 21 extends from the bell 18 and is connected to the connecting strip 15 b means of the bindin' post 16 and is electrically connected by tile retaining screw 9 to the metallic keeper 4.

It is to be particularly noted that no manual switches or circuit-controlling devices other than the contact plate 7 and its adjuncts are included in the circuit and that this normally open circuit is only open at one point, namely; between the resilient con tact late 7 and the keeper 4, It will be noted therefore that the alarm device of my invention is always ready to give an alarm and requires no attention whatever exoept of course an occasional testing to ascertaiii that the batter 17 and other-parts are in good order, an to make this best it'is only necessary to move the door 5; slightly in- Ward, the same as would bedone by 21 burglar 111; an attempt to force the lock. The batteryl'? andbell 18 may of course be located at anyplace desired, but it is considered preferable that the bellal8 should be a loud one ,and that it should be located ina place where it will be heard by the burglar and also by the neighbors, for frightening the burglar against further attempts'at entrance and to arousennd give I notice to other people. Any suitable type of battery, such as the'usual dry cells and an suitable and readily obtainable electric be 1 may be employed in carrying out my invention. U In order to carryout my -invention it is only necessary-toprovide-t e sp'ecial keeper shaving-my nvention embodied: therein and combined therewith, and this keeper embodying' my.'nventionmaybe supplied for min connection with any lock, or it may be supplied and sold separately to replace the ordinary keepennqt hayingim invention in connectlon witb locks -,a11ca in use, it 'being only necessary to; change tli to install my invention for any lock, i

:It,1sito,be noted that theresilient contact plate -7 1s comparatively thin and is only slightly spaced from the innersurface of the frontwall of-the keeperA, and provides for the engagement of the lock bolt 2 back ,of. the contact plate;' l;.i ;The contact plate 7 is still enpughinot to causc-the-bell to ring from. any: slight accidental -vibration of or Q I' glar applies a jimmy to the doorfou forcing cheaper in order 1 it inward to break the lock, the pressure on the door forces the contact plate 7 into contact with the keeper 4, thereby closing the circuit and ringing the bell 18. At each attempt to force the lock the bell will ring and will stop ringing when the effort ceases. Should the burglar try to push back the lock bolt 2 b inserting a thin piece of metal or a kni e blade along the edge of the door from the outside the consequent inward pressure on the bolt 2 will also likewise close the circuit and cause the bell to rin It is obvious that various modifications may be made in the construction shown in the drawings and above particularly described within the principle and scope of my invention.

I claim: 1. An electrical burglar-alarm comprising a metal keeper for a bolt, and a resilient metal contact member mounted at the inside of and electrically insulated from the keeper but adapted to make electrical connection therewith under pressure and arranged to receive the direct pressure of the side of the .loolt upon transverse movement of the bolt in a direction to force the lock, whereby said electrical connection will be made.

2. An electrical burglar-alarm comprising a metal keeper for a bolt, and a resilient metal contact plate carried by and electrically insulated from the keeper at the inside thereof and having a free portion slightly spaced from and adapted to make electrical connection with the keeper under pressure and interposed between the inner surface of the keeper and the side of the locking end of the bolt in the locked position of the latter, whereby to receive the direct pressure of the Copies of this patent may be obtained for the cents each,

side of the bolt end upon transverse movee mefit of the bolt in a direction to force the loc 3. An electrical burglar-alarm combined With a bolt and its metal keeper and comprising an automatically-returning metal contact member normally out of electrical connection with the keeper and adapted to be forced into electrical connection therewith b the direct pressure thereupon of the side 0 the bolt upon transverse movement of the bolt in a direction to force the lock.

4. An electrical burglar-alarm comprising a metal keeper for a bolt, a thin resilient metal contact plate slightly spaced from the inner surface of the bolt-holding wall of the keeper, insulation between the inner margin of the contact plate and said wall of the keeper, the outer margin of the contact plate being free in slightly spaced relation to the wall of the keeper and unsupported and adapted to be ressed into electrical connection with the keeper by the direct pressure thereupon of the side of the bolt upon transverse movement of the bolt in a direction to force the lock, a metallic fastener securing the insulation and the contact late at its inner margin to the wall of the eeper, insulation interposed between said fastener and the contact plate, a metallic connecting strip held by said fastener in insulated relation to the contact plate and in electrical connection with the keeper, a binding post carried by the connecting strip, and another binding post carried by the contact plate.

In testimony whereof I have afiixed my signature.


by addressing the "commissioner at Patentz.

Washington, D. C."

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2660632 *Dec 14, 1951Nov 24, 1953Kenji MakishimaBurglar alarm safety lock
US5062670 *Oct 23, 1990Nov 5, 1991Emanuel GrossmanLock monitor
U.S. Classification200/61.68, 200/61.64, 200/61.58R
Cooperative ClassificationE05B45/083