Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
2000-10-05
2002-10-08
Lieu, Julie (Department: 2632)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S568100, C340S568200, C340S568300, C340S572500, C200S061590
Reexamination Certificate
active
06462668
ABSTRACT:
EXPLANATION OF TERMS (SEE FIG. IV)
Bipolar earthed power cable (
8
)=current-carrying cable having a minimum of 3 conductors (2 for phase, 1 for earth) which connect the poles in the male connector at one end of the cable with the poles in the female connector in the other end of the cable. In addition there may be several conductors to DC alarm circuits.
Connector (
25
)=female connector in the end of the cable which is inserted into the power input terminal on the appliance to be secured. Certified electric equipment, NEMKO (Norwegian Board for Testing and Approval of Electrical Equipment) gr 03 63000, C13 for CLASS 1 equipment, Plug (
28
)=male connector in the end of the cable that is connected to the mains supply (e.g., in a wall socket) `Front part (
26
) of the connector=the part of the connector that is inserted into the input terminal `Rear part (
27
) of the connector=the part of the connector that projects from the input terminal `Chassis=the box around the electrical appliance that is to be secured by the anti-theft alarm cable `Sound unit=sound generator (
1
) and associated battery or accumulator (
2
) `PCB
2
=printed circuit board with the components which can be seen in the diagram in FIG. VIIc)
DESCRIPTION
The invention relates to a bipolar earthed power cable which supplies power to electrical appliances and at the same time has an anti-theft alarm function, wherein the sound generator unit (sound generator+battery) is encapsulated inside the rear part of the connector.
Anti-theft alarm products for electrical appliances that are available today provide inadequate solutions, and do not offer sufficiently good protection against many opportunist thieves. The anti-theft alarm cable is constructed so as to prevent thefts of electrical appliances, especially during the day time, from institutions where even a good admittance control is not enough to stop the thieves.
According to the applicant, an anti-theft sound alarm for electrical appliances should be based on two major criteria: 1) The audible alarm unit (sound generator+battery) must be placed in or close to the chassis of the appliance that is to be secured, primarily to hinder the destruction or deadening of the sound generator. 2) The alarm unit should be securely locked inside the appliance that is to be secured to prevent so-called “hit and run” thefts, where the alarm is cut off, pulled off or in some other manner removed from the apparatus that is to be secured, whereupon the thief runs off with the apparatus and leaves the alarm wailing.
The said criteria can best be fulfilled by a sound-generating alarm integrated in a standard power cable (bipolar earthed) for electrical appliances because: 1) Not all electrical appliances have space available for internal installation. 2) It simplifies the installation of the alarm.
With the anti-theft alarm cable according to the invention, it is ensured that the power cable warns of attempted theft in that the circuit between a sound generator and a battery (optionally an accumulator) is closed upon an attempted unauthorised removal of the power cable from its location between the mains supply socket outlet and the input terminal on the electrical appliance which is secured. Detection of any unauthorised removal can be effected in several ways as described in more detail later in the application.
The essential feature of the anti-theft alarm cable according to the invention is that the sound generator and the battery are positioned as close as possible to the appliance that is to be secured, and furthermore that the encapsulation of the sound generator and battery can be locked in the apparatus that is to be secured.
Anti-theft protection of electrical appliances is achieved according to the invention by closing the circuit between a sound generator and a battery in the event of any unauthorised removal of the anti-theft alarm cable, wherein the sound generator and the battery are encapsulated in the rear part of the connector (FIG. Ia)+b) and FIG. IIa)), so that:
1. The sound unit is protected from sound deadening by an unauthorised person putting the sound unit in a bucket of water or the like.
If the sound unit had been placed along the actual cable instead of in the connector, the thief could have placed the sound unit in a container filled with water, and thus prevented the alarm from being heard when he pulled it out, cut it off or in some other manner removed the anti-theft alarm cable from the appliance to be secured.
2. Physical destruction of the sound unit, for example, by striking it with a hammer or sledge hammer, using a drill or pliers and so forth, will be hindered.
The appliance that is to be secured is in the way of the tool when this task is to be done, thus preventing the tool from gaining access to the critical components.
The apparatus that is to be secured may be destroyed instead of the sound unit in the event of this type of attempted manipulation.
3. It is more difficult to deaden the alarm sound by covering the sound unit with sound-deadening materials such as a bundle of wet clothes:
Because the sound-deadening material is not around the whole sound unit.
Because the area around the input terminal of the electrical appliance is not usually completely uniform (owing to the frame around the input terminal, other connectors or cables and chassis screws and so forth), which makes it difficult to deaden the sound even with good insulating material.
On a number of electrical appliances in the field of application of the anti-theft alarm cable, there are slots and holes around the input terminal which will allow sound into the actual casing around the appliance that is to be secured, so that the sound from the sound unit will not be deadened sufficiently in any case, provided that the sound unit is located in the connector.
4. The sound from the sound generator can be amplified by reflection against the appliance chassis (in the area around the input terminal).
A diaphragm having natural frequency identical to that of the sound generator can be directed towards the appliance chassis, so that the amplitude of the sound waves which are reflected from the chassis are intensified in intersections between the intersecting sound waves.
See FIGS. IIa)+b)
5. Sound holes can be made in the front of the rear part of the connector, so that when an unauthorised persons begin to pull the anti-theft alarm cable out of the appliance that is secured, the following happens:
The sound is amplified considerably in that it is sent out directly from the resonance chamber in the rear part of the connector through open holes.
The sound from the resonance chamber is sent directly into the appliance chassis wall, which reflects it so that the amplitude is further intensified because of interference.
According to the inventor, open sound holes are only justifiable when placed in the front of the rear part of the connector, because unauthorised persons could otherwise fill up the resonance chamber with sound-deadening material, such as foam, fluid or the like. There are 2-3 mm of air in this gap too, which lets out sound directly from the resonance chamber also when the anti-theft alarm cable is right inside the input terminal.
See FIGS. III and IIb).
PCB
2
and the sound unit may be placed inside a metal screen of 0.1 to 0.5 mm of spring steel, before plastic is optionally cast around it.
PCB
2
in the alarm circuit may also be placed inside the connector, and microswitches (tamper controls) can be placed on each side of the circuit board, the pressure arm of which projects the length of its stroke from the circuit board, directed towards each interior of the walls of the metal screen, so that when pressure is exerted on the rear part of the connector from the outside, the metal screen will depress the microswitches, which are connected in the circuit in such a way that they then trigger the alarm. This will trigger the alarm in the event of most attempts at physical manipulation of the
Lieu Julie
Safety Cable AS
Young & Thompson
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