Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
1999-10-18
2001-10-16
Wu, Daniel J. (Department: 2632)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S572100, C340S572400, C340S572700
Reexamination Certificate
active
06304181
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to antitheft systems for protecting merchandise on display in stores against unlawful acts such as shoplifting, and more particularly to an antitheft system which comprises an alarm unit attached to the commodity or like article to be prevented from being stolen for giving an alarm in the event of the unlawful act and an alarm device incorporated, for example, in an antitheft gate for producing an alarm upon the alarm unit giving the alarm.
BACKGROUND OF THE INVENTION
FIG. 8
shows an antitheft system conventionally used in stores wherein commodities such as compact disk cassettes and magnetic tape cassettes are on display for sale, to protect these articles against shoplifting or like illegal acts.
The antitheft system comprises an antitheft gate
5
installed in the vicinity of an exit
8
of the store, and an alarm unit
4
attached to a commodity
7
. The antitheft gate
5
has incorporated therein a circuit board
50
and a transmitting antenna (not shown). The circuit board
50
is provided with a transmitting circuit (not shown) for producing a notifying signal for the alarm unit
4
.
With reference to
FIG. 9
, the alarm unit
4
comprises an electronic buzzer
41
, circuit board
42
, battery (not shown), etc. which are housed in a casing
40
. The casing
40
has a surface formed with sound emitting holes
43
and an alarm actuating switch piece
44
. The electronic buzzer
41
has its operation controlled by the circuit board
42
and is adapted to produce an alarm when the unit
4
is removed from the commodity
7
or when the unit
4
passes by the antitheft gate
5
.
The commodity is placed on display in the store, with the alarm unit
4
attached thereto. When selling the commodity
7
to the customer, the clerk holds the buzzer
41
out of operation by sending a specified signal from a nullifying device (not shown) to the circuit board
42
of the alarm unit
4
, then removes the unit
4
from the commodity
7
and hands the commodity to the customer in exchange for money.
If the customer wrongfully removes the alarm unit
4
from the commodity
7
, the switch piece
44
is turned off to cause the buzzer
41
to produce a sound. Further if the customer acts to unlawfully bring the commodity
7
out of the store along with the alarm unit
4
, the circuit board
42
of the alarm unit
4
receives a notifying signal from the transmitting antenna of the antitheft gate
5
to turn on the buzzer
41
.
However, the antitheft system described has the problem of failing to prevent the theft of commodities reliably since the alarm is emitted only by the alarm unit
4
.
Accordingly, the present applicant has already filed an application for patent on an antitheft system which is adapted to produce an alarm not only from an alarm unit but also from an antitheft gate in the event of an unlawful act so as to give improved reliability to the antitheft system (JP-A No. 279082/1996).
The antitheft gate for the antitheft system has a signal generator for producing a notifying signal for the alarm unit, and an alarm device capable of producing an alarm.
With reference to
FIG. 10
, the alarm unit
6
includes a receiving antenna
61
which comprises a coil L
1
and a capacitor C
3
connected in parallel therewith. The antenna
61
receives a signal, which is then fed to an incoming signal amplification circuit
62
for amplification and thereafter to a control circuit
63
. When the signal from the amplification circuit
62
is a notifying signal from the antitheft gate, the control circuit
63
gives a drive command to an electronic buzzer
64
, which in turn produces a sound in response to the command.
When the notifying signal is received from the gate via the amplification circuit
62
, the control circuit
63
also delivers a signal preparation command to a signal processing circuit
65
, which in turn prepares a second notifying signal. The second notifying signal is amplified in an outgoing signal amplification circuit
66
, then fed to a transmitting antenna
67
comprising a coil L
2
and a capacitor C
4
connected in series therewith and sent out.
The alarm device in the antitheft gate produces an alarm on receiving the second notifying signal from the alarm unit
6
.
The antitheft system described is so adapted that when the customer is about to wrongfully bring out the commodity from the store along with the alarm unit
6
, an alarm is given not only by the unit
6
but also by the antitheft gate. In this way, an improvement is made for more reliable prevention of theft of commodities.
However, the alarm unit
6
of the antitheft system, which has the receiving antenna
61
, circuits
62
,
63
and electronic buzzer
64
for giving an alarm in response to the notifying signal from the antitheft gate, further comprises the circuits
65
,
66
for preparing and processing the second notifying signal and the transmitting antenna
67
and therefore has the problem that the alarm unit
6
is large-sized and difficult to attach to small commodities.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an antitheft system adapted to prevent the theft of commodities, etc. with high reliability and comprising an alarm unit which is easy to attach to small commodities.
Directing attention to the fact that the electronic buzzer
64
incorporated in the conventional alarm unit
6
shown in
FIG. 10
generates electromagnetic waves when driven, we conceived the idea of utilizing the electromagnetic waves generated by the electronic buzzer
64
to dispense with the circuits
65
,
66
for preparing or processing the second notifying signal and the transmitting antenna
67
. Thus, we have completed a first antitheft system according to the present invention.
The present invention provides a first antitheft system which comprises:
a notifying signal generator for producing a notifying signal,
an alarm unit to be attached to an article to be prevented from being stolen and comprising an electronic buzzer, signal receiving means for receiving the notifying signal from the notifying signal generator, and first control means for operating the electronic buzzer upon the signal receiving means receiving the notifying signal, and
an alarm device comprising alarm means capable of producing an alarm, electromagnetic wave receiving means for receiving electromagnetic waves generated by the electronic buzzer by operating the electronic buzzer, and second control means for operating the alarm means upon the electromagnetic wave receiving means receiving the electromagnetic waves.
When the first antitheft system is installed, for example, in a store for selling commodities, the notifying signal generator is disposed in the vicinity of an exit of the store, and the commodity to be protected against theft is on display as connected to the alarm unit. The alarm device is housed in a casing along with the notifying signal generator, or singly in a casing separate from a casing for the notifying signal generator, and the casing or casings are provided in the store.
If the customer is about to wrongfully bring out the commodity from the store, the signal receiving means of the alarm unit receives a notifying signal from the signal generator, whereupon the first control means operates the electronic buzzer, causing the buzzer to produce a sound.
The operation of the buzzer generates electromagnetic waves therefrom which are received by the electromagnetic wave receiving means of the alarm device, whereupon the second control means operates the alarm means, causing the alarm means to produce a sound.
When the customer is about to unlawfully bring out the commodity from the store which is equipped with the first antitheft system of the invention, an alarm is given not only by the alarm unit but also by the alarm device, whereby the theft of the commodity can be prevented with higher reliability than by the conventional antitheft system which produces an alarm only from its alarm unit.
Since the electromagnetic waves generated by th
Arent Fox Kintner & Plotkin & Kahn, PLLC
Pham Toan
Sanyo Electronics Co., LTD
Wu Daniel J.
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