US3378832A

US3378832A - Burglar alarm system

Info

Publication number: US3378832A
Application number: US480075A
Authority: US
Inventors: Liou Shu-Lien
Original assignee: Individual
Current assignee: Individual
Priority date: 1965-08-16
Filing date: 1965-08-16
Publication date: 1968-04-16
Anticipated expiration: 1985-04-16

Description

April 16, 1968 SHU-LIEN LIOU BURGLAR ALARM SYSTEM Filed Aug. 16, 1965 R O m V m JHU-L/f/V A /00 United States Patent 3,378,832 BURGLAR ALARM SYSTEM Shu-Lien Liou, 195 Sec. 3, Chungkiug Road N., Taipei, Taiwan Filed Aug. 16, 1965, Ser. No. 480,075 13 Claims. (Cl. 340-274) This invention relates to alarm devices for indicating unplanned or unauthorized actions including burglar alarm systems.

The invention relates particularly to a device which can indicate unauthorized operation of a mechanism. For example, it will set off an alarm signal if a lock is opened by anyone who does not first arrange associated elements in a predetermined position.

While locks do much to prevent theft, there are some particularly brazen thieves who have the skill or the equipment to unobtrusively open locks. Some have sets of skeleton keys. Others know techniques for picking locks, or other methods of opening them without keys. Some can open combination locks by particular manipulations. Pickpockets have been known to deliberately steal keys to a desired lock. Persons who know such techniques are also likely to have the intelligence and the skill to open locks without attracting public attention. They may be well dressed and nothing about them may suggest thatthey are thieves.

Unauthorized lock operation triggers an alarm bell under this invention. A tape recorder shouting Stop thief! or some similar message may be included.

Alarm systems actuated by unauthorized atempts to use locks were known in the days of Queen Elizabeth in the sixteenth century, and many have been suggested since that time. However, they do not appear to have achieved widespread use, perhaps because they were overly expensive, unreliable, or too easy to circumvent.

The invention is also useful to indicate unauthorized use of machinery. For example, it can attract attention to unauthorized use of an automobile. The invention might also be applied to industrial machinery which might be damaged by unqualified employees. The embarrassment of setting off a bell that attracts the attention of a whole factory can teach such an employee a lesson that might save his life.

A major object of this invention is the provision of a device to indicate unauthorized use of mechanisms including locks invarious types of machinery.

A further object is to provide such a device which is cheap to manufacture, reliable in operation, simply operated, and small in size so that the presence of the device is not apparent to those who plan such unauthorized use.

Briefly stated the invention consists of an alarm system which is activated by use of a mechanism, for example, by opening a lock with a key, unless the operation of the alarm system is circumvented. Operation of a concealed device is necessary to circumvent the alarm system. The concealed device may be similar to a combination lock and can only be operated by a person who knows the proper combination to manipulate the dial to the off position.

In one embodiment of the invention applicant mounts a small spring so that it will move with a link in a door latch mechanism as the door is opened after unlocking. This spring has a projection that moves into a notch formed in the sides of a number of concentric disks of equal size. By operation of a dial similar to that of a combination lock, the notches in the individual disks are brought into alignment to form an opening to receive the straight projection. If this opening is not formed movement of the door latch carries the projection against 3,378,832 Patented Apr. 16, 1968 "ice the side of the disks, and further movement of the projection closes electrical contacts to activate an alarm system.

Other objects and advantages of the invention will be apparent from the following drawings in which:

FIG. 1 is a plan view, partly schematic of a portion of a door latching and locking mechanism utilizing the present invention;

FIG. 2, a perspective view of a spring member utilized with the structure of FIG. 1;

FIG. 3, a plan view illustrating another embodiment of the invention;

FIG. 4, a side view of the structure of FIG. 3 showing the mechanism of FIG. 3 with the mechanism for actuating a burglar alarm in the inoperative position;

FIG. 5, a side view of the structure of FIG. 3 showing the mechanism of FIG. 3 with the mechanism for actuating a burglar alarm in the operative position; and

FIG. 6, a perspective view of a spring member used in the mechanism of FIG. 3.

With further reference to FIG. 1 of the drawings, a movable member 10 of a door latch mechanism 11 includes arm 12 normally blocked in locked position by a bolt 14 of a lock mechanism 15. Movable member 10 may be any part whatever that moves when a door is opened after it is unlocked. Movable member 10 also has an arm 13 with a projecting part thereon blocked in locked position by a combination dial lock 18 comprising a number of separate disks 19 each of which has a notch 20 cut therein. If notches 20 are aligned and bolt 14- is moved out of locking position movable member 10 can move to the right by moving the projecting part into the large opening formed when the three smaller notches 20 of the individual disks 19 are brought into alignment.

A bracket 23 secured to movable member 10 has a fiat rectangular metal spring member 25 secured to it by rivet 28 and spacer 29. Spring member 25 has a central strip 26 cut out and bent first away from the arm 23 and toward combination lock 15 and then back through the central opening 27 of the spring member 25. The bottom of central strip 26 is mounted in a groove 33 in a bar 31 and biases it against the bottom of

slots

34 and 35 cut in front wall 36 and rear wall 37 of bracket 23. Bar 31 extends through the opening 27 of spring member 25 and has a wider part 32 at one end.

A combination mechanism 40 has a number of disks 41 each with a notch 42 cut therein. When notches 42 are brought into alignment they form a larger opening in which wider portion 32 of bar 31 can move when lock 15 and combination lock 18 are unlocked. However, if notches 42 are not aligned wider portion 32 of bar 31 strikes the side of combination mechanism 40 as movable member 10 travels to the right. Front wall 36 of bracket 23 carries an electrical contact 45 separated from it by insulator 46. Spring member 25 also carries an electrical contact 47. An electrical circuit 50 joins these electrical contacts through power source 51, audible alarm 52, a tape recorder 53, and the intermediate structure.

The operation of the device of FIG. 1 is as follows: Normally the door is kept locked "by bolt 14 and combination lock 15 and electric contacts 45 and 47 are normally spaced from each other by a distance which is greater than the distance between either arm 12 and bolt 14 or arm -13 and combination lock 18. Accordingly, the electrical contacts are not moved to engaging position by moving member 10 slightly while locked. Accordingly, persons testing the door to see whether it is locked or children playing would not normally set off the alarm.

However, if an unauthorized person who manages to move bolt 14 out of the way as by picking the lock or obtaining the key without authority and if he is further able to manipulate combination lock 18 to open position must move latch member 10 to the right to open the door. However, member 10 carries bar 31 with it and when wider portion 32 strikes the edge of combination mechanism 40 spring member 25 bends to the right as a reaction to the movement of bar 31 to the left. This closes the electric contact to ring the bell. Any type of bell or any other alarm signal desired can be used. If desired a tape recorder can also be connected to call out Stop thief! or other messages such as A burglar alarm has been actuated! Please call the police.

FIGS. 3 to 6 illustrate an alternative form of the invention. A pair of

latch mechanism members

110 and 111 each have notches 112 cut therein. These notches can be brought into alignment to form a larger opening by any appropriate mechanism. When a door is opened latch members 110 and 11 1 move in the vertical direction as shown in FIGS. 3, 4, and toward an alarm actuating mechanism 115. Actuating mechanism 115 includes spring holder 120 having a front wall 121 and a rear wall 122 joined by side wall 123. An offset portion of the front wall 121 carries an electrical contact 125 which is insulated therefrom. A spring member 130 is slidably mounted between front wall 121 and rear wall 122. Spring member 1130 consists of a long flat strip of metal bent into a generally U shape. One leg 131 of the U is formed by

portions

132 and 133 bent upon themselves. The other leg 134 consists of portion 135 of the strip.

Legs

131 and 134 are joined by center projection 138 consisting of portion 139 which is bent outwardly from portion 133, portion 140 bent inwardly to extend post leg 131, and portion 141 bent back toward leg 131 and which joins leg 134. The springiness of the metal tends to keep the legs well spread. Spring 1330 is normally mounted in spring holder 120 with

portions

139 and 141 of projection 138 spaced from front wall 121 and rear wall 122. An electrical contact 143 on leg 134 engages electrical con tact 125 if spring 130 is pushed further into spring holder 120. Wires 146 and 147 of the alarm circuit join

electrical contacts

143 and 135.

The device of FIGS. 3 to 6 operates as follows: spring member 130 is normally retained between the front and

rear walls

121 and 122 with projection 138 in an extended position as illustrated in FIG. 3. The door is unlocked and notches 1-12 of

latch members

110 and 111 are moved into alignment.

Latch members

110 and 111 are moved toward mechanism 115' and projection 138 moves into the opening formed by notches 112. No electric circuit is closed and the alarm does not ring. On the other hand, if the

latch members

110 and 111 are moved toward the alarm mechanism without aligning the notches: (1)

members

110 and 111 strike the projection 138; (2) spring member 130 moves further into holder 120; (3) spring leg 134 and electrical contact 143 move and engage the other electrical contact 125; and (4) the alarm circuit is actuated.

It will be readily apparent that a device has been provided which is simple in structure, reliable in operation, and economical to manufacture. This device will actuate an alarm if the lock mechanism or any other mechanism is operated without first arranging certain elements in a predetermined position.

It will be obvious to one skilled in the art that various changes may be made in the invention without departing from the spirit and scope thereof, and, therefore, the invention is not limited by that which is illustrated in the drawings and described in the specification, but only as indicated in the accompanying claims.

What is claimed is:

1. A device for indicating unauthorized operation of a mechanism having relatively movable members comprising,

(A) a first member having (1) a first part mounted thereon,

(2) a second part mounted for movement relative to the first part,

(B) a second member (1) mounted for movement relative to the first member,

(2) means to selectively provide an opening in the second member of an appropriate size and shape to receive the second part of the said first member during operation of the mechanism, and,

(3) means to move the said second part of the first member relative to the first part as the first member moves toward the second member at times when said means for forming an opening are not actuated,

(C) an alarm signal means, and,

' (D) means to activate said alarm signal means when relative movement occurs between the first part and the second part of the first member.

2. The structure of claim 1 in which said second member is an assembly of relatively movable parts each having an indentation therein, and the means for providing an opening comprises means to relatively move said parts so that the indentations are aligned.

3. A device for indicating unauthorized attempts to operate a mechanism comprising,

(A) a mechanism,

(B) a support connected to the mechanism,

(C) a first member on the support,

(D) a second member on the support,

(E) means on the support to cause relative movement of the said first member toward the second member when said mechanism is operated,

(F) said first member having means to selectively provide an opening in its side,

(G) said second member having (1) a fixed part having (a) spaced side members defining an opening therebetween extending in the direction of relative movement between the first and second members,

(b) an offset portion fixed to one side member and carrying an electrical contact located on the side of the opening opposite the said first member,

(2) a generally U-shaped spring metal member (a) slidably mounted within the opening in the fixed part,

(b) one leg of the U carrying an electrical contact so located so that it can engage the electrical contact on the offset portion of the said fixed part in response to sliding movement of the U within the said opening,

(c) having the portion joining the legs of the U extending from the side of the opening and forming a projection so located that it can move into the said opening in the side of the first member,

(H) an alarm signal means, and

(I) means to activate said alarm signal means when said projection moves toward said fixed part on the second member.

4. A device for indicating unauthorized attempts to operate a mechanism comprising,

(A) a mechanism,

(B) a support connected to the mechanism,

(C) a first member on the support,

(D) a second member on the support,

(F) said first member having means to selectively form an opening in its side,

(G) said second member having (1) a fixed part carrying an electrical contact thereon and (2) an elongated springy sheet metal member (a) having an electrical contact on one end (b) secured to the fixed part at its opposite end at a position such that ilexure of the elongated springly sheet metal member will bring its electrical contact into engagement with the electrical contact of the fixed part,

(c) an elongated strip out within the central portion and bent to curve away from the member on the side opposite the fixed part at its end nearest its electrical contact, said strip being then bent to curve back in toward the said member,

(3) a movable rod (a) mounted within the opening in the spring metal member and (b) engaging the end of the elongated strip of the spring metal member,

(c) said rod so located that it will engage the side of the first member and cause the spring metal member to flex and bring the electrical contacts into engagement as the second member moves relatively to the first unless said opening has been made in the side of the first member,

(H) an alarm signal means, and

5. A device for indicating unauthorized operation of a mechanism having relatively movable members comprising (A) a first member having (1) a first part mounted thereon,

(2) a second part associated with said first part and means mounting the second part for movement relative to the said first part,

(B) a second member (1) mounted for movement relative to the first member, and

(2) having selectively actuated means for causing relative movement between first and second parts during relative movement of said first and second members during operation of the mechanism,

(C) an alarm signal means, and (D) means to activate said alarm signal means in response to relative movement of the said first and second parts. 6. The structure of claim 5 in which said mechanism is a lock mechanism.

7. The structure of claim 5 in which said mechanism is a lock mechanism actuated by a key.

8. The structure of claim 5 in which said first part and said second part are electrical contacts and the means to activate the alarm system includes an electrical circuit joining the said electrical contacts.

9. The structure of claim 5 in which said alarm means produces an audible signal.

10. The structure of claim 5 in which said alarm means includes a tape recorder.

11. The structure of claim 5 in which said alarm system includes a bell.

12. The structure of claim 5 in which said second part includes a metal spring.

13. The structure of claim 5 in which the movable mounting for said second part includes a metal leaf spring carrying an electrical contact, and said first part also includes an electrical contact positioned so that relative movement between the said parts brings the electrical contacts into engagement, and the means to activate the alarm system includes an electrical circuit adjoining the said electrical contacts.

References Cited UNITED STATES PATENTS 1,424,298 8/19 2 Gifford ZOO- 1,708,279 4/ 1929 Milliken 200-45 2,003,650 6/1935 Hosking.

JOHN W. CALDWELL, Primary Examiner.

D-. L. TRAFTON, Assistant Examiner.

Claims

1. A DEVICE FOR INDICATING UNAUTHORIZED OPERATION OF A MECHANISM HAVING RELATIVELY MOVABLE MEMBERS COMPRISING, (A) A FIRST MEMBER HAVING (1) A FIRST MEMBER HAVING (2) A SECOND PART MOUNTED FOR MOVEMENT RELATIVE TO THE FIRST PART, (B) A SECOND MEMBER (1) MOUNTED FOR MOVEMENT RELATIVE TO THE FIRST (2) MEANS TO SELECTIVELY PROVIDE AN OPENING IN (2) MEANS TO SELECTIVELY PROVIDE AN OPENING IN THE SECOND MEMBER OF AN APPROPRIATE SIZE AND SHAPE TO RECEIVE THE SECOND PART OF THE SAID FIRST MEMBER DURING OPERATION OF THE MECHANISM, AND,