Package

This invention relates to the art of packaging and it has particular relationship to determining if a package which is assumed to be intact has been undesirably opened. This invention is applicable not only to bottles and boxes such as are used in the food, beverage and pharmaceutical industries, but, also, to sealed documents which may be classified or valuable. The word "package", as used in this application, includes within its meaning not only bottles and boxes, but, also, sealed documents.

Sharpe, U.S. Pat. No. 4,398,089, is typical of the prior art. Sharpe discloses a container including a radiation shell shielded from radiation detectors by a shielding shell. Sharpe states that when the container is broken, the shielding shell is ruptured and the detector picks up the radiation actuating an alarm. This expedient involves the hazards of radioactivity. In addition, Sharpe does not describe what its radiation material is and what kind of radiation it emits. Gamma radiation would require a heavy lead shield. An alpha radiation emitter such as Pu238 also emits gamma rays. The gamma rays would be present inside and outside of the container and would require shielding.

It is an object of this invention to overcome the disadvantages of the prior art and to provide for monitoring the integrity of packages without relying on radiation material.

In accordance with this invention, an electrical oscillatory network, i.e., a tuned resonant network, without a power supply is connected between the closure of a package or container and the body of a package. The network typically includes a one-turn spiral of conducting material overlapping at the inner and outer ends. This structure forms a one-turn inductance having a capacitance by reason of the overlapping ends, in parallel with the inductance, i.e., a parallel tuned network. The one-turn spiral is printed, by the methods of producing printed circuit boards, on a film of insulating material. The film seals the opening of the container. A dab of uncured adhesive is adhered to a region of the spiral. When the package is closed by the closure, the dab is engaged by the inner surface of the closure. After the adhesive is cured, the closure cannot be opened without tearing the electrically conducting spiral where the dab is adhered. The oscillatory network is thus broken.

The use of a multi-turn spiral is also within the scope of equivalents of this invention. In this case, the capacitance is formed between the innermost and outermost turns. The intervening turns serve, in effect, to reduce the dielectric distance between the innermost and outermost turns which has the effect of increasing the capacitance.

The package is monitored by a transmitter-receiver, typically under the counter over which the package is passed when purchased by a customer. The transmitter emits oscillation over a frequency band including the resonant frequency of the network. These oscillations are modulated by pulses. On the counter the electrical oscillatory network is in the field of the oscillations emitted by the transmitter. The oscillations are impressed on the network at the pulse intervals, each pulse transmitting energy to the network, exciting the network to emit a decaying pulse. After the transmission of the pulse ceases, the induced oscillations in the oscillatory network decay because of energy losses resulting from the network resistance and from electromagnetic radiation. Since the oscillatory network has a high Q, the decaying oscillations persist for an appreciable interval and can be detected. For intact packages, the receiver produces a signal corresponding to the received pulse during the interval between transmitted pulses. Typically, the signal may be an audio signal corresponding to the pulse rate. If the package is opened and the oscillatory network has been broken, then no signal is produced, indicating that the package is not intact.

For a better understanding of this invention, both as to its organization and as to its method of operation, together with additional objects and advantages thereof, reference is made to the following description taken in connection with the accompanying drawings, in which:

FIG. 1 is an exploded view in isometric of apparatus embodying this invention and for practicing the method of this invention;

FIG. 2 is a partially diagrammatic view in isometric of an electrical oscillatory network assembly included in the apparatus shown in FIG. 1;

FIG. 3A is a partially diagrammatic view in isometric showing the first step in the formation of another electrical oscillatory network assembly;

FIG. 3B is a partially diagrammatic view in isometric showing a succeeding and final step in the formation of this other electrical oscillatory network assembly;

FIG. 4 is a generally diagrammatic view in isometric showing an embodiment and practice of this invention for monitoring the integrity of a package closed by flaps;

FIG. 5 is a schematic illustrating an electric oscillatory network used in the practice of this invention;

FIG. 6 constitutes a graph illustrating the operation of this invention; and

FIGS. 7 and 8 are block diagrams for showing the manner in which a package is monitored in the practice of this invention.

The apparatus shown in FIG. 1 is a package 21 including a bottle 23 and a cap 25. The bottle is open at the top and includes an external thread 27 around its rim at the top. The thread 27 is engaged by mating internal thread along the lower rim of the cap 25. An electrical oscillatory network assembly 29 is interposed between the cap 25 and the bottle 23. The assembly 29 (FIG. 2) includes a film 31 of insulating material on which a one-turn spiral 33 of electrically conducting material is printed by a printed circuit process. The spiral 33 forms an inductance. The overlapping ends 35 and 37 of the spiral are insulated from each other and form a capacitance in parallel with the inductance. The spiral 33 and its overlapping ends 35-37 form an electrically oscillatory or parallel tuned network. It is desirable that the network 33-35-37 have a high Q and to achieve this purpose, the conductors forming the spiral 33 should be highly electrically conductive.

The film 31 is sealed to the rim 39 bounding the opening in the bottle 23 after the content of the container is deposited therein. A dab 41 of uncured adhesive is deposited at a region of the spiral and the immediately surrounding film. The cap 25 is then threaded onto the thread 27 closing the bottle 23. The dab 41 of adhesive extends above the film 31 to an elevation at which it adheres to the inner surface of the cap 25 when the cap is threaded onto the bottle. When thereafter the adhesive 41 is cured, the spiral 33 is adhered to the cap 25 so that removal of the cap breaks the tuned network.

FIGS. 3A and 3B show another electrical oscillatory network assembly 50 in preliminary state and 51 in a finished state. This assembly includes a network 53 whose capacitance is higher than for the network shown in FIGS. 1 and 2. As a first step illustrated in FIG. 3A, there is deposited on a film 55 of insulating material an electrically conducting configuration consisting of a loop 59 whose ends 61 and 63 overlap and are spaced a short distance from each other. The overlapping ends terminate in adjacent spaced conducting areas 65 and 66 which, preferably, are congruent. As a succeeding step (FIG. 3B), the film 55 is folded along a line 67 between the areas 65 and 66 substantially bisecting the space between them so that the area 65 under the fold 67 is aligned with the area 66 above the fold. The areas 65 and 66 and the film between them form a capacitor whose dielectric is the two layers of film. A dab 71 of uncured adhesive is deposited over the loop 59 and the immediately adjacent film for physically connecting to a closing part, such as the cap 25 or a flap, so that the network 53 is broken when the closing part is opened.

The apparatus shown in FIG. 4 includes a box 81 closed by overlapping inner and outer flaps 83 and 85 and 87 and 89 respectively at its opposite ends. An electrical oscillatory assembly 51 as shown in FIG. 3B is adhered to flap 83 and an assembly 51a to flap 87. After the box 81 is filled with its content, the flaps 85 and 89 are adhered to the dab 71. When the box 81 is opened at either end, the unfolding of the flap 85 and 89 breaks the network 53 and 53a adhered to the opposite flap 83 and 87. The networks 53 and 53a are tuned to different frequencies which can be distinguished readily. The difference may be effected by dimensioning the areas 65 and 66 (FIGS. 3A, 3B) of network 53 differently than the same areas for network 53a.

Packages such as 21 (FIG. 1) or 81 (FIG. 4) are monitored as they are passed over the counter 101 (FIG. 7) where a purchase is processed. Under the top of the counter 101, there is a transmitter-receiver 103. The monitoring can be understood by consideration of FIGS. 5 and 6. FIG. 5 shows schematically a parallel tuned network 111 which corresponds to the networks 33-35-37 (FIGS. 1, 2) and 53 and 53a (FIGS. 3B and 4). This network 111 includes a capacitance 113 and an inductance 114. As shown, the capacitor typically has a capacity C of 10.sup.-10 Farads and an inductance L of 10.sup.-6 Henrys. The resonant frequency is 1/.sqroot.LC or 1.sqroot.=10.sup.8 Hertz. For monitoring the package 21, the transmitter-receiver 103 includes a transmitter 115 which produces pulse modulated trains of oscillation 117 (FIG. 6a). The carrier oscillations are typically over a frequency band peaking at 10.sup.8 Hertz. Typically, the duty cycle of the pulses is 10% and the power output of the transmitter 115 is 0.1 milliwatt pulse power. For package 81, the transmitter 115 and receiver 119 are constructed to produce alternate pulse modulated oscillations whose carriers peak at the different frequencies to which networks 53 and 53a are tuned. This enables the moitoring simultaneously both ends of the package 81 to determine if the flaps 83-85 or 87-89 have been opened.

The package 21-81 is positined typically about 1-foot from the transmitter 115 in the field of output of the transmitter. The receiver 119 is blocked during the transmitter pulse 117 (FIG. 6) and is gated having a nominal threshold typically of 1 microwatt at 10.sup.8 Hertz. On receiving a pulse from the transmitter 115, the capacitor 113 is charged and the network 33-35-37 or 53 or 53a is set into oscillation producing decaying oscillations 120 (FIG. 6). The resulting emissions are received and detected by the receiver 119, following the interval during which each transmitter pulse is blocked, thus producing a train of decaying pulses 120 (FIG. 6) having trailing ends. The trailing ends constitute a train of detectable emissions picked up by the receiver. The transmitter-receiver 103 includes an audio or visible indicator 123 (FIG. 8). If the package 21-81 is intact, the indicator 123 produces a signal corresponding to the train of detected emissions, if not, no signal is produced. This process may be reversed. The indicator may be set to produce a signal when a break is detected in the package 21-81. To prevent the indicator from producing signals between moitoring operations, the detector may be gated, for example, by a normally-open microswitch under the counter, which is closed by a package 21-81 when it is place on the counter.

While preferred embodiments and preferred practice of this invention have been disclosed herein, many modifications thereof are feasible. This invention should not be restricted, except insofar as is necessitated by the spirit of the prior art.