US531955A

US531955A - Burglar-alarm

Info

Publication number: US531955A
Authority: US
Publication date: 1895-01-01
Anticipated expiration: 1912-01-01

Description

(No Modpl.) 2 Sheets-Sheet 1.

0. LARSON.

BURGLAR ALARM.

No. 531,955. Patented. Jan. 1, 1895.

(No Model.) 2 Sheets-Sheet 2.

O. LARSON. BURGLAR ALARM.

' No. 531,955. Patented Jan. 1, 1895 W OM 2 UNITED STATES PATENT EEioE,

OLAUS LARSON, OF CHICAGO, ILLINOIS.

BU RGLAR-ALARM.

SPECIFICATION forming part of Letters Patent No. 531,955, dated January 1, 1895. Applicatlen filed July 6, 1894- Serial No. 516,768. (No model.)

To all whom it may concern:

Be it known that I, OLAUS LARSON, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Burglar-Alarms; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to an improved burglar alarm, adapted to be attached to a door or look.

The object of theinvcntion is to provide a simply constructed and eflicient apparatus, which may be readily attached to the escutcheon plate orlock of a door in such manner that a key or other instrument cannot be inserted to unlock the door without causing an alarm bell to ring, and thereby to arouse the occupant of the room, and give timely warning of impending intrusion; and which is also adapted to be electrically connected to sound an alarm at the same time in other rooms of the building or elsewhere.

The invention consists in the combination and arrangement of parts, the novel features of which are hereinafter fully described and set forth, reference being had to the accompanying drawings, in which- Figure 1 is a side elevation of my improved burglar alarm shown in an operative position attached to the section of a door and lock. Fig. 2 is a vertical section of the apparatus taken on the

line

2, 2, of Fig. 3, the alarm bell being shown in full lines. Fig. 3 is a view of the inside face with a portion broken out to show the clock gearing within the bell. Fig. 4 is a top view of the apparatus partly cut away.

Referring to the drawing-1. designates the door which as represented is of the ordinary kind provided with the usual escutcheon or key-hole plates 2, and mortise lock 3, into which a key 4 is shown partly inserted.

5. is the alarm bell within which a clapper 6 is pivotally attached to a crank, and adapted to be rapidly rotated and carried around therewith to ring the hell by means of clock gearing operated by a clock spring, adapted to be wound up by the lever key 7, and held by a ratchet wheel and pawl. The construe tion of the bell and gearing by which it is made to ring is without novelty, being identical with that in general use for alarm clocks, and will be readily understood without further reference thereto. Said bell and appurtenant parts are rigidly secured to a flange disk 8, to the inside of which an escapement pawl i) is pivotally attached. The lower end of the pawl is bent and projects through the disk plate, and is adapted to engage with the bell clapper to stop the bell. Said pawl is made to engage said parts by means of a flat steel spring 10 resting thereon, the outer end of which is rigidly secured to a flat rock arm or pivoted lever 11 in manner resembling a bell crank. Said lever projects outward through the disk-flange, and is for the purpose of moving the spring from one end of the escapeinent pawl to the opposite end; or, to change or remove the spring pressure from one side of the pawl supporting pivot to the other side thereof as is shown by dotted lines in Fig. 3. When said springis in the position of the full lines, the projecting end of the pawl is pressed to engage with the clapper and stops the bell; but, when the spring press ure is transferred to the opposite side of the pivot, the pawl will be lifted to ring the bell, unless an opposing pressure intervenes to prevent itand such is the case. The act of attaching the apparatus to a door carries forward an opposing or counteracting spring of slightly greater power than that exerted by the flat spring, which is turnedto the position of the dotted lines after the apparatus is attached, so that the flat spring must be aided when the apparatus is set in order to lift the pawl and start the alarm; the object and manner of doing, which will be made apparent farther on.

12. is a head-stock or frame, the bottom of which is curved to fit the disk-flange, and is rigidly secured thereto. Said frame bottom has ear formed portions 13 which are turned downward, and pass through perforations in the disk-flange. Said ears are perforated for the insertion of the curved distance wire it, which is adapted to be sprung therein, and to be turned up against the door for the lateral support of the apparatus.

15. is acylindrical steel tube fitted into perforations in the uprights of said head-stock frame, and is rigidly held therein. One end of said tube projects outward therefrom, and

' is provided with a plurality of integrally formed branches or fingers 16, which are closed together at their ends, and reduced in diameter to normally admit the insertion therein of the key-push-rod l7, and for the insertion of said finger ends into the smallest key-hole forwhich the apparatus is designed. Said fingers are spring tempered, and have outward projecting ends adapted to hook behind the escutcheon plate, or to be forced into the wood if the door is without a plate.

18. is an inner tube adapted to be moved forward longitudinally within the finger-tube to expand said fingers, and secure the apparatus to the door, and to be moved backward therein to permit the resilient closing of the fingers for the detachment of the. apparatus therefrom. Said inner tube has a disk 19 attached to its outer end by which it is moved and adjusted, and is provided with a pin 20, rigidly secured thereto. Said pin projects through a slotted opening 21 in the top of the finger tube; the slot having notches 22 formed upon one side thereof, into which said pin is adapted to be turned to form a lock and prevent the inner tube from being pushed back by the finger pressure thereon, or from possible pressure applied through the key-hole.

23. is a cylindrical plug fitted to the inner tube, and adapted to slide therein. Said plug has a central bore, into which the key-push rod 17 is inserted and adapted to be adjusted to stand out such distance as is required by the thickness of the door, and to be rigidly secured to said plug when adjusted by means of a set screw 24 in the plug, and a series of circumferential grooves 25 formed upon the push-rod, by which arrangement, though it were possible to turn or revolve the push-rod from the outside, it cannot be twisted off and removed to make room for the key. Said cylindrical plug is provided with a downward projecting pin 26, which passes through a slotted opening 27 in the inner tube, and also through a like slot 28 in the finger tube; the inner tube slot being cut wider to permit the turning the tube when it is to be locked.

29. is a spiral springinterposed between the end of the cylindrical plug and disk end of the inner tube, the spring being held slightly compressed therein by the pin in the plug resting against the end of the slot in the inner tube. It will now be seen that in attaching the apparatus to the door, the pin in the plug will be carried forward by the movement of the inner tube which at the same time expands the fingers, until it is brought to bear against the upper end of the escapement pawl (see Fig. 1) upon the opposite of which the flat spring is now turned to act, and as the force of the spiral spring is greatest the flat spring cannot act to lift the pawl to ring the alarm until its force is made predominant, or greater than the opposing spiral spring, and thisoccurs the moment the push-rod is pressed back,

and the pressure of the spiral spring upon the pawl is either lessened or removed therefrom by the insertion of a key or otherinstrument; the arrangement producing a positive and sensitive action, requiring but a slight pressure upon the push-rod to ring the bell.

30. is a flat metal plate secured to the headstock frame to form a support for the hand or fingers in pushing the inner tube to attach the apparatus.

The operation consists in attaching the apparatus to the dooras described, adjusting the push-rod to the desired point in the lock, and turning the flat spring to press upon the upper end of the escapement pawl.

It will be observed that thepush-rod may be extended out into the look far enough to prevent the full insertion of the key, or it may be withdrawn to a point that will admit of its being pushed back sufficient for the key to be operated-to unlock the door, and that by this arrangement the occupant of a room may leave his room door locked with the alarm attached thereto, so that persons in other parts of the house would be notified, should entrance be made other than at the usual hour-of departure and return.

The invention'is' one of great utility and efficiency, and in its adaptation and convenience of attachment to "and removal from a door, forms a desirable alarm appliance; and is. especially useful as an adjunct to a travelers outfit, its size being such that it may be conveniently carried about the person or in a hand-bag.

The apparatus is constructed chiefly of brass,but may beof any suitable material, and plated or finished in any desirable manner.

, I am aware thatitis not a new per se to ring an alarm hell, by mechanical means, and I make no claim to such as my invention.

In my invention the alarm apparatus is adapted to be readily attached toa door or look by means of the key-hole therein, and so sensitized that any tampering with the lock instantlysets the alarm bell ringing.

Having thus fully described my invention, I claim- 1. In an alarm apparatus adapted to be operated by the insertion of a key or other instrument into the lock of a door the combination therewith of the described spring formed expansible fingers, adapted to be attached to said apparatus, and to be inserted into the key-hole or lock of a door, and means adapted to expand said fingers in said keyhole to secure said alarm apparatus to said tobe inserted in the key-hole of a door or lock,

and to be expanded therein to secure said apparatus to said door; and akey-push-rod-held centrally between said fingers, and adapted to be pushed back by the insertion of a key into said lock and door to lift said escapement pawl, and thereby to cause said alarm bell to ring substantially as and for the purpose specified.

3. In the described burglar alarm apparatus, the combination of the fingers adapted to be expanded within the key-hole of a door to secure said apparatus thereto; a push-rod extending into said key-hole, and held centrally therein between said fingers, a pivoted escapement pawl, adapted to be lifted by the movement of said push-rod, to allow the alarm bell of said apparatus to ring and a spring acting against said pawl, and adapted to be moved thereon to transfer the pressure of said spring to either side of said pawl pivot substantially as and for the purpose specified.

i. The combination in the described alarm apparatus of a fixed cylindrical tube provided with integrally formed fingers, adapted to be inserted into the key-hole of a door; an inner tube inserted within said fixed or finger tube, and adapted to be moved therein to expand said fingers in said door key-hole, to secure said apparatus thereto, and to be turned and locked therein against being moved back in said finger tube when said fingers are expanded; a cylindrical plug inserted within said inner tube; a key-push-rod inserted in said cylindrical block, and longitudinally adjustable therein as described, a spring inserted into said inner tube, adapted to act against the end of said cylindrical plug, and an escapementpawl, adapted to be held in a locked or non-escapement position by means of said spring, substantially as and for the purpose specified.

5. The combination in the described burglar alarm apparatus comprising a bell, clock gearing, adapted to be wound up to ring said bell; a pivoted escapement pawl to control the ringing of said bell; said bell and parts attached to a circular flanged disk, a spring adapted to be moved to either end of said pawl, or upon either side of its pivot connection by means of a lever attached thereto; a pivotally attached distance or supporting rod, adapted to be turned down within said flanged disk, a head-stock frame attached to said flanged disk, a tube rigidly attached to said head-stock; said tube provided with integrally formed expansible fingers, adapted to be inserted into the key-hole of a door or look, a movable inner tube, adapted to expand said fingers to secure said apparatus to a door, a cylindrical plug within said inner tube, pro vided with an adjustable key-push-rod, and a spring within said inner tube, adapted to press against the end of said plug, and also to be brought to bear against said escapement pawl, combined and arranged in the manner and for the purpose substantially as specified.

In testimony whereof I affix my signature in presence of two witnesses.

OLAUS LARSON.

YVitnesses:

EDWARD S. CURTIS, OLNEY B. STUART.