WO2003058277A2 - Metal detector integrated with site-existing pathway - Google Patents

Abstract

A method and system for utilizing a site-existing pathway for monitoring and preventing access to or egress from a designated area by a source of a threshold amount of metal. The system comprises one or more field coil modules (10), a power supply module (12), one or more field coil modules (10), and an electronic module (14), all interconnected with one another. The field coil modules (10) are adapted for placing in a location which does not restrict the pre-existing pathway, but which utilizes the pathway to appropriately position the source of metal in a detection zone for effectively searching the source. The electronics module (14) is adapted to receive and process an electrical signal from the one or more field coil modules (10), to indicate whether the threshold amount of metal has been detected, and to prevent access or egress from the designated area.

Description

METAL DETECTOR INTEGRATED WITH SITE-EXISTING PATHWAY

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from and incorporates herein by reference, U.S. Provisional Application No. 60/345,140, filed by Malcolm M. Schwartz on January 2, 2002.

FIELD OF THE INVENTION

The invention relates to metal detection, and specifically the integration of metal detection technology with site-existing barriers (or equivalents) for controlling progress of metallic content or risks and/or for monitoring metals as parameters of intelligence.

BACKGROUND OF THE INVENTION

Metal detection principles are well known and are often conveniently divided into passive and active classifications. Most of this technology is in the public domain.

Passive metal detection is relatively sophisticated, utilizing the earth's own varying magnetic field as an established norm and using instruments such as magnetometers and gradiometers to register anomalies in that magnetic field caused by magnetic materials. Roadway sensors for traffic control, geodetic survey programs, and sensor systems to avoid land mines are all examples of systems utilizing passive metal detection technology.

Active technology generates its own detection field with a transmitter means and, after balancing for its operating environment, registers metal-caused anomalies with a receiver means. Handheld treasure hunter devices, such as those used by hobbyists for uncovering metal in beach sand, as described by U.S. Patent No. 3,662,255 to Garrett, incorporated herein by reference, utilize this technology. Walk-through detectors and handheld wands, such as are familiar for use in airport or courthouse security also utilize active technology. Detection vestibules and turnstile formats used for access control, such as described in U.S. Patent No. 5,992,094 to Diaz and in numerous domestic and foreign patents dating back through the years, also use active metal detection technology. Although usually custom-designed for specific applications, industrial detectors, such as may be used to detect metallic contaminates, are typically also based upon active technology principles of one source or another.

There are several types of active technology known in the art, such as 5 unbalanced oscillator circuitry, pulse field circuitry, and continuous field circuitry. Unbalanced oscillator circuitry technology is commonly used for handheld metal detectors and treasure hunter designs. Pulse Field circuitry is a U.S. Government development that is used by most walk-through devices. Continuous field circuitry, as known and used in the art by Friskem Infinetics of Wilmington, Delaware, may be 10 used with multi-receiver channels that are each separately programmed, offering a high degree of discrimination, reliability, and efficiency.

Many techniques are employed to increase the utility of detector art. Some designs feature more than one search channel. Each may be programmed to discriminate target metals from those of no interest. Some designs offer zonal ι₅ suggestion of target location on the searchee's body and some designs feature shaped field patterns and other means to control detection coverage. Other techniques may modify the field to best suit target size or alter field frequency to avoid electric interferences. Such techniques can often be achieved with minor changes in semi-standard designs without major cost.

₂o Despite the important and even life-saving benefits provided by the metal detection art, however, its utilization has apparently been insufficiently attractive to foster wide-spread or commercially significant adoption for the varied needs of society outside of the typical airport- or courthouse-type systems.

Prior to the present invention, the metal detection art has typically 2₅ served two primary markets of noteworthy commercial monetary value. The ground search market is mostly hobby-related, such as for coins on the beach, and has undergone relatively minor engineering advancement over the years. People- searching is the much larger market and is typically centered upon governmentally- controlled applications, such as airports, courthouses, and the like, that typically 30 dictate procurement at lowest unit price with less regard for other considerations.

A consideration of the systems typically employed for weapons searching in airports illustrates why prevailing practices have severely limited wide adoption of metal detection technology by general society, despite the many persons and/or sites fearful of threats stemming from publicized reports of home invasions, ₃₅ robberies, political unrest, terrorism, and other violence, as well as industrial concerns and potential military applications, such as Intelligence Surveillance Reconnaissance (ISR) sensors. Airport searches using both handheld and walkthrough detectors requires trained operators, traffic-control staff, and response- trained support officers. Such staffing incurs noteworthy labor costs on a continuing daily basis — an expense normally beyond the resources available to most private interests, such as householders, retailers, offices, and the like. Both handheld and walkthrough methods require considerable operating space, which is often simply not available for most private interests.

Additionally, both handheld and walkthrough types of devices inherently require the operator to be directly exposed to the potential threat posed by the searchee. While that risk may be acceptable to police-type operators, it may be totally intolerable to other classes of users. Although turnstile and rat-trap versions of detectors may lessen the exposure problem to some degree, such devices continue to need major space, and their architectural ramifications increase cost by noteworthy amounts, which may not be acceptable to users with limited funds.

Handheld detectors are easily dropped and as a result must be frequently fixed or replaced entirely. Even lowest grade walkthrough detectors cost several thousands of dollars, mainly because their structure must prevent movement that invalidates operation. Structural wobble is one of the main reasons such devices commonly need replacement after only a few years of service. Maintenance is also a major expense, usually requiring the services of trained personnel who must incur travel costs coming from distant bases of operation.

Because new airports, prisons, courthouses, and the like are not often built, this detector marketplace understandably has historically shown relatively low growth. Detector products have accordingly become sideline accessories from firms involved in other pursuits, such as x-ray inspection devices and explosive detectors, for whom the typically much more expensive devices relating to these other pursuits consume available engineering capabilities. It can then be easily appreciated why metal detectors today are virtually identical to designs of 25 years ago, beyond outward decor and internal componentry.

Other access control applications of metal detection technology — detection vestibules and turnstiles — require elaborate structure and are further burdened by architectural and regulatory cost additives. These dictate enormous prices that can be justified in only rare situations. While financial problems and space provisions are solved in a governmental program by passing costs along to taxpayers or, for example, air passengers, such solutions are not practical for private interests, who typically forego the security protection of a metal detection program purely because of the expense and other problems which have evolved.

Although there are numerous industrial applications that could benefit from metal detection art, these are commonly individualized, custom designs which preclude realizing the cost savings of volume-produced detectors. Such applications may entail costly on-site visitation by designers and require expensive structures where space may be an added problem. Many at-risk sites cannot financially justify the expenditure and must pass on this solution despite the serious nature of their concern. Meanwhile, although military applications of ISR from ground sensors is presently in its infancy, the cost of such often non-reclaimable items is likely to be an issue in determining what base technology can be afforded.

Thus, to make metal detection technology more attractive and widespread in many heretofore untapped markets, it is desirable to solve concerns related to labor/equipment expenses, and space requirements, while also providing systems that limit a user's involvement in the operation of such devices, limit exposure to danger, and provide means for risk disposal, when risks are detected. Furthermore, it is desirable to provide such technology in a format that is suitable for mass-production with its inherent potential for cost savings.

SUMMARY OF THE INVENTION

One aspect of the invention is a method for monitoring and preventing access to or egress from a designated area by a source of a threshold amount of metal. The method comprises utilizing a site-existing predetermined pathway between the designated area and a connected area, the pathway comprising a traffic zone having a size for accommodating passage through the pathway. A metal detector is installed for detecting the threshold amount of metal passing through the traffic zone, the detector being installed in a location which does not restrict the size of the traffic zone within the pathway, but in which the pathway appropriately positions the source of metal in a detection zone relative to the metal detector for effectively searching the source for the threshold amount of metal. The method then comprises monitoring for an attempt to pass through the detection zone with at least the threshold amount of metal, and providing information regarding such an attempt to a means adapted to respond to the attempt, and physically preventing the source from access to or egress from the designated area.

The "threshold" amount of metal may be an amount that is the lower limit of metal detectible by the detector, or may some greater amount of metal that is characteristic of the type of source intended to be detected (i.e. a gun, a vehicle, a tank, etc.). The term "traffic zone" refers to the portion of the pathway through which persons, vehicles, object, or the like must pass to utilize the pathway. Thus, for example, whereas an existing pathway between terminal A and terminal B in an airport has a traffic zone which is defined by the walls of the passageway between which the passengers must walk, a standard airport walk-through metal detector restricts the traffic zone by forcing the traffic to pass through the detector structure. By contrast, the method of the present invention does not restrict the traffic zone of the site-existing pathway to provide metal detection.

The means adapted to respond may, for example, be an electronic processor or a person, including a person who may be the source carrying the threshold amount of metal or a remote person having an interest in who or what attempts to enter or exit the designated area. The means to respond to the attempt may comprise, for example, means for providing a visible and/or audible signal, such as an instruction to the person who is the source of the metal to take a specific action, such as to divest all metal and try again. In one exemplary embodiment, the metal detector may be concealed or disguised to provide surreptitious monitoring, such as for military surveillance purposes, and may have remote signaling capability.

By "physically" preventing access or egress from the "designated area", it is meant that there is some specific structure or action that actually prevents access or egress. For example, the site-existing pathway may comprise a physical barrier having means for controlling passage through the barrier, wherein the metal detector is positioned to detect the threshold amount of metal prior to passage of the source past or through the barrier; and wherein the response to the attempt to pass through the detection zone with at least the threshold amount of metal comprises disallowance of passage past or through the physical barrier. In one exemplary embodiment, the physical barrier may comprise a door in which the means for controlling passage may comprise an automatic lock/unlock system integrated with the door.

In another exemplary embodiment, the predetermined pathway may comprise an industrial pathway, including but not limited to a conveyor or roll path, step of physically preventing access or egress may comprise removing the source of metal from the industrial pathway, including a step of initially marking the source and later removing it. In the surreptitious monitoring embodiment, the step of physically preventing access or egress may comprise receiving the remote signal and responding by disabling further progress of the source of metal, such as by using military force. It should be noted that the detector may be mounted inside or outside the "designated area," and that the designated area may extend beyond the immediate area where the detector is located. For example, in an industrial pathway where the source is marked for later removal, the step for marking the source may occur well upstream of the physical removal step. Similarly, in the surreptitious monitoring application, such as a military application, the detection step may be occur a substantial distance away from the location of the physical disabling step. The term "physically preventing" can be distinguished from the use of a metal detector as is known in the art to operate a traffic signal, where the presence of a car above a sensor plate is used to control a traffic light. In the traffic light example, the car is not physically prevented from moving, as the driver of the car has the option of disregarding the traffic signal.

Another aspect of the invention comprises a system for utilizing a site- existing pathway for monitoring access to or egress from a designated area by a source of metal. The system comprises one or more field coil modules, a power supply module, and an electronics module, all of which are interconnected with one another. The one or more field coil modules are adapted for placing in a location which does not restrict the pre-existing pathway, but which utilizes the pathway to appropriately position the source of metal in a detection zone relative to the one or more field coil modules for effectively searching the source for the threshold amount of metal. The electronics module is adapted to receive and process an electrical signal from the one or more field coil modules, to indicate if metal is detected, and optionally to activate means for responding to the metal detected. The one or more field coil modules is adapted to be placed in a position in a relationship to a physical barrier having means for controlling passage through the barrier, where the threshold amount of metal can be detected prior to passage of the source past or through the barrier.

In one exemplary embodiment, the field coil module comprises a single, portable field coil module that is adapted to be rolled for transport and storage when not in use. In another exemplary embodiment, the field coil module comprises a transparent casing that encloses the one or more field coils. In yet another exemplary embodiment, the system may comprise automatic means for controlling passage through the barrier, such as for example, an automatic door lock/unlock device. In some embodiments, the system may comprise one or more indicators for signaling when the threshold amount of metal is detected, such as an audible indicator, a visual indicator, or a combination thereof. Other types of indicators may also be used. Where the predetermined pathway comprises an industrial pathway, the system may comprise means for removing the source of metal from the pathway upon detection of at least the threshold amount of metal or for marking the source of metal upon detection of at least the threshold amount of metal. Where the predetermined pathway comprises a pathway for supporting vehicular or pedestrian traffic, the system may further comprise means, such as for example a radio transmitter, for sending a remote signal to a control device, such as for example, a radio receiver, the signal indicating a presence or absence of vehicular or pedestrian traffic carrying the threshold amount of metal within the pathway. The field coils module, power supply module, electronics module, and radio transmitter may be concealed or disguised to minimize detection by persons in the predetermined pathway, such as in the form of a cigarette package or a naturally occurring object.

Another aspect of the invention comprises a system for indicating presence of an object having a threshold amount of metal in a pre-existing space for the object, such as a parking spot for a car (or other land vehicle) or a docking slip for a boat (or other water vehicle), the system comprising one or more field coil modules, a power supply module interconnected with the one or more field coil modules, and an electronics module interconnected with the one or more field coil modules and the power supply module. The one or more field coil modules are adapted for placing in a location which does not restrict the pre-existing space, but which utilizes the pre-existing space to appropriately position the source of metal in a detection zone relative to the one or more field coil modules for effectively searching the source for the metal. The electronics module is adapted to receive and process an electrical signal from the one or more field coil modules, to indicate if metal is detected, and to send a signal indicating presence or absence of the object in the pre-existing space.

The metal detector typically comprises a transmitter coil and a receiver coil, utilizing any of a number of metal detection technologies well-known in the art. In one embodiment, both the transmitter and receiver coils of the metal detector may be attached to or mounted within the barrier. For example, the metal detector may be mounted within or behind a substantially non-metal door. "Substantially" non- metal means that any metal present can be designed around by those skilled in the art by accounting for the metal in the system set-up so as to not interfere with accurate metal detection. For all-metal doors or doors with metal that cannot be readily designed around, the metal detection field may be provided in front of the barrier. For example, the transmitter may be mounted on or below a floor surface and the receiver may be mounted above the transmitter, or vice versa, creating a vertical path between them for passage of the person or thing to be searched. As an example, the metal detector may comprise one field coil module placed in or on the floor, such as in a floormat, and another above the door, such as in an awning hung above the floormat, in front of a door. In yet another embodiment, the metal detector may comprise a pair of appendages extending away from the door into the unsecured area, such as attached to the door frame, creating a metal detection zone in the area between the appendages in front of the door. Various metal detection technologies known in the art permit numerous design approaches. For example, the use of field coil modules in which the transmitter and receiver coils are located together on the same side of the pathway allow for use of only the floormat or the awning field coil module, not both, or only a single appendage.

Another aspect of the invention comprises portability for traveling users with a metal detector adapted to be temporarily mounted on a surface to detect the presence of metal behind the surface. For example, where the surface is a vertical surface such as a non-metal door, the portable detector may be a plastic sheet having the metal detector coils mounted therein, wherein the sheet may be affixed to the door to detect metal on a person at the door of, for example, a motel. The sheet typically is affixed to the door in a manner such that there is no movement of the coils, as is well-known in the art. Similarly for the other embodiments discussed herein, stability (non-movement) of the coils during operational stages is important.

The metal detectors discussed herein typically comprise a set of field coils, a power source, and a monitor for communicating to the user that metal has been detected. In some embodiments, these components may be integrated with an electronic door lock/unlock device such that the lock may be locked or unlocked depending on the signal received from the metal detector. Thus, a normally unlocked door may automatically lock if metal is detected. In another embodiment, a normally locked door that is remotely unlockable and equipped with the metal detector may provide a signal to a human controller of the remote door lock indicating that metal is present on a person at the door, so that the controller can decide not to unlock the door. The metal detector is typically adjustable for ambient conditions and for desired thresholds by the user, as it well-known in the art.

Another aspect of the invention comprises a method of providing metal detection technology in a format readily usable by consumers, the method comprising providing a family of metal detection modules adapted for interconnection with one another in a plurality of potential interconnected combinations, each combination comprising at least one field-coil module adapted to be installed in a site-existing pathway, at least one electronics module, and at least one power supply module. The method may further comprise providing a plurality of output devices adapted to be interconnected with the electronics module.

Certain embodiments of the present invention provide an inexpensive way for a user, such as a storeowner, to protect entry into a secure area, such as his store. The invention does not require an operator for the metal detector, but rather can be integrated into a site-existing barrier, such as a door having an existing automatic door lock system. The invention also does not require additional structures, space, or operating staff such as are required for the use of a walkthrough or handheld metal detector, but rather makes use of a predetermined path, such as the path through the entry door of an establishment. The use of the site- existing barrier and automatic locks mean that there is no added expense for operating staff and that no person has to face the risk of an armed intruder because the armed intruder is never let in the door in the first place. Of course, although most cost-effective when used with a site-existing barrier and door lock system, the invention may also be provided along with a new barrier and/or door lock system. Similarly, although described with respect to an exemplary application for a store, the invention may be used in any number of diverse applications where metal presence, types, and amounts may present unique issues to be addressed.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 depicts an installed exemplary embodiment of the present invention installed on an entry door;

Fig. 2 depicts an exemplary modular power module, electronics and control module, and field coils module.

Fig. 3 illustrates a field coils system comprising a transmitter and receiver field coils mounted in a single unit on a door with associated accessories of major metallic content located overhead to minimize field distortion potential.

Fig. 4A illustrates an exemplary system comprising field coils mounted within appendages on a non-secured side of an entry door to provide a cross-aisle search pattern across the approach path.

Fig. 4B illustrates an exemplary system comprising field coils mounted in an overhang and/or floormat on a non-secured side of an entry door to provide a vertical search pattern across the approach path.

Fig. 5 illustrates an exemplary industrial application comprising an exemplary metal detection system for package inspection. Fig. 6 illustrates an exemplary surveillance application comprising a metal detector disguised as a discarded cigarette package.

DETAILED DESCRIPTION OF THE INVENTION

The invention will next be described with respect to the various exemplary embodiments shown in the figures. There is no single preferred embodiment since such will vary to best suit a specific situation and application of the numerous possibilities.

Fig. 1 depicts a domicile application to illustrate the simplicity and minimal expense of self-installation. A field coils module 10 is mounted by any means known in the art, such as for example with screws (not shown), to an entry door 11 that is substantially non-metal, for example a wooden door. Power module 12 is plugged into a standard electrical receptacle 13, and an electronics and control module 14, also referred to herein simply as the "electronics module," is shown sited on a table, but can be mounted on the wall or placed anywhere desired by the user. Upon a doorbell ring or knock for entry, module 14 may be inspected to ascertain if the search reveals metal over a threshold level for the user's preferred reaction. Although shown in connection with a door in Fig. 1, the metal detector may be mounted on any site-existing physical barrier having means for controlling passage through the barrier. Barriers comprising vertical surfaces, such as a hinged or sliding door, a ticket window, and the like, may be particularly suitable for use of embodiments of the present invention.

Fig. 2 provides a more detailed view of exemplary embodiments of components typically present in some form in all the embodiments described herein. The components may be connected together using cables 20 outfitted with plugs 21 or other quick-connectors known in the art. The electronics module and field coils may also have independent power supplies and may be in electrical communication via wireless technology well known in the art. Power module 12 is shown adapted to plug into a standard electrical outlet. Although shown with a standard U.S. two- prong plug 22, the power module may be equipped to be compatible with the power grid and standard plug connectors used in any country of the world. The power supply may instead be a battery power supply (not shown) typical of battery power supplies well known in the art, including a rechargable battery, or may comprise a combination of battery and plug-in power supplies. A battery power supply may be particularly useful for applications outdoors, or the military, vehicular versions, or for travelers. The power module and/or electronics module typically contain the appropriate electronics and transformers to step down the standard power grid voltage to an amount necessary to run the electronics module and/or the field coils. Although shown in Fig. 2 with the power module and the field coils module connected to the electronics module, the interconnection of the three modules may be in any combination. As used herein, the reference to these modules being "interconnected" with one another includes any possible arrangement of the components, including embodiments wherein the electronics module and field coil module have independent power supplies and have only a wireless interconnection with one another.

Detection field coils module 10 is encased within a non-metallic material for ready rigid mounting. The coils may vary in number and chosen technology, size, and shape for the desired coverage and associated design parameters. For applications such as retail shops and offices, it may be desirable to fabricate the coils within a transparent material, to also allow visual evaluation of a searchee through a standard clear glass/plastic entry door. Such an embodiment resembles the door 11 and field coils module 10 arrangement shown in Fig. 1, except that both the door and field coils module are see-through, and thus the actual coils inside the field coils module are visible. For portable use, such as by travelers, the field coil module, such as module 10 shown in Fig. 1, may be adapted to roll-up or fold to fit within a suitcase and then be ready to temporarily fasten, such as with tape, to the inside of the door of an overnight lodging.

The electronic and control module 14 shown in Fig. 2 is basic version, such as for homes and the like. Switch 23 turns power on and off. A fuse 24 suitable for providing a desired degree of electrical protection may be present. With switch 25 in the BALANCE position, adjustment knob 26 allows adjusting needle 28 on signal display meter 27 to a minimum desired to accommodate ambient conditions. Some module versions may feature automatic balancing that automatically calibrates for ambient conditions. The automatic calibration may occur when powering the unit, and/or may be initiated by pushing a CALIBRATE button (not shown), or may be initiated in any way known in the art. With switch 25 in the THRESHOLD position, knob 26 allows adjusting the display meter needle 28 to a desired threshold setting, above which the alert light 29 will illuminate. Switch 25 is then put into the

OPERATE position and subsequent search results are displayed on meter 28 by the needle position until the cause of the disturbance is removed by, for example, searchee departure or purposeful cancellation by push button switch 30.

The many variables encountered in the numerous possible applications for the invention may foster an extensive family line of selectable modular versions to cost-effectively serve those applications. Digital signal display (not shown) rather than an analog display such as needle 28, may be desired for better accuracy, especially for discriminate detection programs and multiple search channels. Various accessory-type activators may be desired, potentially with switching and adjustment alternatives and means. For example, for the traveler having a roll-up field coil module to easily fit in his suitcase along with the power and electronics modules may also desire a monitor module that includes a read-out delay, in case he is sleeping and needs reaction time after the door-knock. Audio alerts with off/on options may also be provided for certain applications. An office installation may desire distance- remoting, for a receptionist next to or near the door. A remote door lock release may also prove helpful, along with an audible or visual alarm-alert to a distant source of assistance. In a retail store, remote door lock releases in various handy locations may be desired. Monitors with a variety of readouts suggesting exemplary weapon- sizes corresponding to the amount of metal detected and/or with a selectable threshold audio alarm are other desirable accessories. Some sites may prefer their unit be in standby mode, to be activated only when the door-pull is grasped by a person seeking entry. Upon alarm, it may sometimes be helpful to illuminate a visual or audible advisory such as "Excess metal ~ divest and try again" or similar instruction.

The mere deterrence itself of having such a metal detector as described herein may be helpful, furthered by a sign advising those seeking entry that they will be searched. Affordable metal detection may enable private citizens to protect their own domicile and/or, for example, a child's dorm room at college. Metal detection technology may be integrated with existing commercial offerings from home or business security companies. In the commercial realm, retail stores with high-priced goods such as jewelry stores, and business with late-night hours, such as convenience stores, gas stations, drug stores, etc., may benefit from the present invention. Hotels and motels may permanently install such protection, or offer portable devices to patrons who wish such protection. Offices and other facilities of potential targets such as politicians, corporate VIP's, prosecutors and other lawyers, as well as medical complexes and facilities handling money, such as banks, check- cashing operations, box offices, finance firms, tax collectors, and the like may all benefit from the present invention.

Commonality of many components and design may enable the cost- savings inherent to mass production, while selection of a casing design accommodating multiple embodiments may help control supply costs. When desired, extreme miniaturization with microprocessors and chips may be practiced. Modular choices may tend to be affected by user desire for nearly automatic operation without interference in his usual activities. Fig. 3 illustrates an exemplary wood or other non-metal door 11 having a field coils module 10 mounted thereon with brackets 31. The transmitting and receiving functions originate from a single module 10, similar to the technology known in the art. As shown in Fig. 3, it may be desirable to locate accessories like a closer device 32 and automatic lock 34 on the top-side of the door, out of the way, where their interference signal potential is of lesser concern. Such location is not mandatory, however, and systems may be tailored so that these devices may be located wherever desired.

Fig. 4A illustrates one alternative mounting of field coils 40 for an application in which metallic components of door 42, for example, make it inconvenient to replace or design around the existing door. Field coils 40 in this example are mounted within appendages that are rigidly mounted to the building or door frame on the approach, non-secured side. They achieve a cross-aisle detection field horizontally across the approach path, like a walk-through detector, but without its large structure, expense, or space consumption. Referring now to Fig. 4B, using a floormat 44 and overhang 46 can provide an alternative with a similar cross-aisle detection field, but oriented in a vertical direction as opposed to the horizontal direction shown in Fig. 4A. In other embodiments, overhang 46 may comprise both the transmitter and receiver field coils in a single module searching downwards without a specially-equipped floormat below, or floormat 44 may be a similar transmitter/receiver module searching upwards without an overhang. The embodiments shown in Figs. 4A and 4B may typically feature connection cables (not shown) passing into the building, and may be protected from tampering and weather adversities in ways known in the art.

Risk-disposal with the system and methods for searching people as described above may be as simple as those refused entry walking away, or perhaps a sign suggesting the searchee to divest metal and try again. Searches at airports and courthouses have sufficiently accustomed the general public to security programs, such that the general public understands such procedures and can appreciate the necessity of potential inconvenience.

Fig. 5 illustrates an industrial safety-type application of inspecting for contaminate metal in packages using an existing industrial pathway. As used herein, the term "industrial pathway" refers to any type of conveyor, roll path, slide path, chute, pipeline (preferably non-metal), or the like along which discrete objects or bulk materials may pass or flow in an industrial setting. Searches of discreet items are similar to a people-search in that the system may control further progress of the risk and prevents its entry into a secured area. To appreciate the potential danger, for example, consider cotton bales collected in truck loads from many sources and not identifiable by grower. To meet tare-weight upon delivery, the grower may have inserted scrap metal, knowing bales are stored for years to insure against times of bad crops. When eventually cart-rolled from storage to the processing plant, if a contaminated bale enters processing, it may damage machinery and cause a shutdown. If it is found before entry, it can be cart-rolled away to a correction area and preclude such danger.

In the embodiment illustrated in Fig. 5, packages 50 are conveyed by a slide-down chute 52 from one area to another, such as from a processing operation to a shipping operation. Search inspection uses a single integrated transmitter/receiver field coils module 54 that operates from an overhead suspension 55. Risk-disposal can use a commercial sliding drop-out hatch 56 (shown after having slid to an open position in the direction of arrow A from its closed position shown in dashed lines), or paint marking of failures, or conveyor knock-off devices, and the like. Substantially non-metallic conveyor belts may enable use of single- source field coils mounted from above as shown in Fig. 5 or detecting upwards from a floor mounting below (not shown), whereas cross-path field-coils analogous to those shown in Fig. 4A, rigidly mounted from side to side, may be used with a metallic conveyor belt. Metal detection systems may be used for determining proper metallic content, or for the simple counting of metallic items.

In industrial applications featuring loose or bulk materials which are commonly dropped out of a spout, may use a single transmitter/receiver module or cross-path detection field coils to inspect for metallic contaminate or for proper amounts of any purposeful metallic additives. Risk-disposal in such applications is normally accomplished by spout shut-off and manual correction, or via the use of a diversion device into a failure container. On-site professionals like plant engineers are accustomed to facilitating their own needs when necessary modular equipment is commercially available. Much the same, the military has its own sources of design engineering to utilize available sensory equipment.

Fig. 6 illustrates a potential version of a ground level sensor useful for military ISR purposes. The exemplary device shown in Fig. 6 comprises a cover 60 to disguise the device as a cigarette packet, which may be placed or air-dropped in relation to a pre-ordained travel path, such as for example a mountain pass, to look as if it has been discarded. The three main modules (power, field coils, and electronics) may thus be encased together with an accessory radio transmitter for communicating the information detected. The embodiment shown in Fig. 6 schematically shows battery power module 62, electronics 64, field coils 65, and radio transmitter 66, all mounted within casing 61. Although illustrated in Fig. 6 as a cigarette packet, which is a frequently discarded item seen among litter on the ground and not likely to attract attention, the design is not limited to any particular embodiment, and other innocuous disguises are equally imaginable, particularly disguises resembling other types of frequently discarded items or naturally occurring objects such as rocks, plants, tree limbs, and the like.

In addition to miniaturization, such surveillance sensors may simplify by eliminating components to conserve space. For example, battery insertion may automatically power-up the unit without a switch, and the selection of field coils for the unit may serve to provide automatic thresholding (i.e. one set of field coils may be selected with sensitivity tailored to detect tanks, another may be tailored to detect vehicles, and yet another may be tailored to detect personal arms). Solar power with or without battery back-up may be used, and signal transmission, such as for drone- plane collection, may be programmed to transmit only when metal over the desired threshold is detected, or during darkness periods. Noting the presence or absence of data at various times between multiple sensors spaced predetermined distances apart from one another may supply speed data. Other variants are also practical. A novel aspect of this invention is the method of providing metal detection technology in a format readily usable by consumers. By providing a family of mass-produced metal detection modules adapted for interconnection with one another in a plurality of potential interconnected combinations, the invention provides a methodology by which consumers not previously able to utlilize such technology may use it. Essentially, by providing a plurality of field-coil modules adapted to be installed in a site-existing pathway, including modules adapted for use on a single side of the pathway, including transparent modules for use on glass doors, portable modules for rolling or folding for storage to be used in traveling, modules adapted for use on opposite sides of a pathway, such as door appendages or overhang/floormat type modules described above, consumers may choose from a selection of field coil modules to suit their needs. By providing power supply modules of various sizes, consumers can provide the amount of power needed for the necessary application, using, for example, a chart recommending the power needed for a given application. The amount of power needed in the field coils, for example, may be dependent on the size of the field coils, the distance from the field coils at which the metal needs to be detected, and the types of output devices, if any needed to be powered.

A family of electronics modules may be provided that are adapted to drive a number of output devices. The modules can be manufactured such that they are readily customizable at minimal cost. For example, a base unit may have no actual output slots for output devices, but may have a casing and internal design adapted for easy insertion of output device drivers and associated connectors, much in the way that personal computers are commonly designed with slots for a variety of output devices, memory cards, graphics cards, and the like.

The plurality of optional output devices adapted to be interconnected with the electronics module may include door lock/unlock systems, audible and/or visible indicators as described above, radio transmitters for sending signals to remote devices, cable-connected remote read-outs of the amount of metal detected, devices for marking sources of metal on conveyors, and digital or analog signal outputs for providing a signal to be integrated with any control system known in the art, for example an industrial distributive control system that controls the requisite parts of a conveyor to separate sources of metal from the rest of the objects on the conveyor.

Accordingly, once the methodology of this invention becomes known and its modular components are commercially available, all sorts of expanded applications may be expected, and adaptations beyond those few exemplary embodiments that are cited and illustrated herein are to be expected.

As noted, metal detection technology is well-known in the art. Technology comprising coplanar transmitter and receiver coils, such as are described by Garrett, noted above, may be used for embodiments of the present invention in which the transmitter and receiver are located in a single integrated unit on the same side of a pathway, such as those mounted within a door structure or within a temporary structure for affixing to a door. The technology used by standard walkthrough metal detectors known in the art comprising a transmitter coil on one side and receiver coil on the other (or both sides electronically alternating between transmitter and receiver), may be used for providing overhang-to-floormat arrangements or arrangements with metal detecting appendages extending away from the door, as shown in Figs 4A and 4B.

This invention introduces a unique methodology to solve many of the concerns previously tending to limit wide adoption of metal detection art for a diversity of applications. Exemplary embodiments of the present invention can provide alert, protection, and intelligence information relative to metallic content in a manner affordable for even private interests.

Site-existing barriers or equivalents, including points in space (such as along a traveled path), are equipped with metal detection capabilities for achieving control or monitoring systems. Further progress of metal can be thwarted by formatting a secured area that can prevent entry, that can prevent exit, that can trigger reactions like disposal means, or that can supply intelligence information. Known but differing metal detection technologies and various techniques may be formatted into a versatile family of selectable, design-related modules. Such modules can allow self-installation and other virtues to minimize costs of outsider services. The large number of possible uses can enable the cost savings inherent in mass production of related designs, and the relative ease of custom modifications may increase usage and may justify advancing technology. The various potential uses can allow operating an extensive range of accessories. Differing modes of operation are also enabled, including virtually full automatic operation with users free for normal activities and not involved with operations or exposure to danger, and with no need for costly labor facilitation.

This invention utilizes normal or pre-ordained paths of travel, such as but not limited to doorways or ticket windows (or paths thereto) or along train tracks or roadways, to eliminate costly structure and search space that present walkthrough detectors and overly-slow handheld searches consume. Industry can gain such advantage by using conveyor paths or equivalent and can add disposal means to their arrangements. Disposal of risk in people searches can be as simple as the risk walking-away or by divesting the metal, such as in response to a written or audible advisory. In military uses, aircraft or artillery can dispose of risks.

Thus, the attributes of this invention overcome the burdensome constraints of traditional detection methods, equipment, and practices in a viable and cost-effective manner. Worldwide society is thereby enabled to enjoy the capabilities of metal detection art in reducing fears of endangerment and safety hazards, and to gain the advantages of derivative uses of this novel innovation to suit their individual interests.

The system is operationally installed of appropriately selected modules for the task, according to simple instructions without a need for special tools or expertise. Installation time is minimal. The detection coils module is mounted in relation to the barrier and the power and electronics modules are sited in relation to the user's convenience. Upon powering, the system is manually adjusted or automatically self-adjusts for its operating site and can then display a readout signal- size proportionate to the ambient situation. Introduction of target metal into that established environmental ambient will normally increase the displayed signal size. From chart guidance or actual trials with some selected targets, signal levels appropriate to a rejection threshold level can be ascertained and set into the electronics module. Exceeding that threshold may be normally arranged to activate the alarm alert and barrier protection, as well as associated accessories like remote indicators, cameras, disposal means, and the like. Signals of search less than the threshold level may cause no action or, in other modes of operation, may cause desired acceptance-based actions like unlocking a barrier door. The displayed signal level of search will normally continue until its cause has been removed or is cancelled by an override control. The readout signal then returns to displaying the ambient level.

Other modes of operation are equally useful as may be preferred in say industrial and military usages. Without any direct contact or moving parts in the metal detection system (not considering connected accessories like automatic door locks), the electronic systems may need relatively little periodic maintenance, as well as essentially no operational labor in even continuous service. A modular failure may be readily returned for factory repair without outsider services. Predictable service- life expectancy is so extended as to render equipment expense a negligible factor. These attributes coupled with the versatile methodology of this invention suggest rather unending derivative applications in fields far beyond that of safety, security, industrial, and military uses discussed.

Examples of additional uses for the metal detection technology may include location and positioning information that may be helpful for insertion of medical stents, where the pathway comprises a body lumen. Distance and speed indications using geographically spaced sensors may be useful in tracking rail freight schedules. Monitoring absence presence of metal can be helpful in verifying the presence of absence of a metal object in a particular space, such as a docking-slip for a boat or other water vehicle, or a parking spot for a car or other land vehicle (i.e. a garage for a car or a terminal gate or other ground location for an airplane, which can be considered a land vehicle when not in the air). Monitoring waterways may be useful in bridge-raisings. Monitoring material feeds are useful throughout manufacturing, such as in automotive parts and food packaging. Military ISR data collection can utilize almost all these parameters, plus others. Relatively inexpensive instrumentation having electronic accuracy and remote readout may have a nearly endless scope of uses.

The structures and methods of this invention are not limited to any particular applications. Security and safety applications may include search of persons and packages attempting to exit a secured area, such as with stolen tools or products, or attempting to enter a secured area, such as with weapons, or other metal risks, such as for example, sparkable metals that may cause explosion in petro-chemical sites or magnetics that could cause accidents in medical Magnetic Resonance Imaging sites, and the like. Applications in industry and military can include search for non-appropriate metals, for example, in bales of cotton in the clothing industry, bags of cement in the construction industry, frozen blocks of chicken in the food industry, and other quality-control type programs in many fields. Other exemplary uses may include verification of proper packaging content using signal size and the counting of packages, for example, on conveying means. Still more examples may include indicators, monitors, and like instrumentation of metal for collecting data regarding presence/absence, location/position, machine settings, distance, speed, motion, electrical emissions, and similar parameters useful for intelligence purposes in military and industrial programs.

While preferred embodiments of the invention have been shown and described herein, it will be understood that such embodiments are provided by way of example only. Numerous variations, changes and substitutions will occur to those skilled in the art without departing from the spirit of the invention. Accordingly, it is intended that the appended claims cover all such variations as fall within the spirit and scope of the invention.

Claims

What is Claimed :

i 1. A method for monitoring and preventing access to or egress

2 from a designated area by a source of a threshold amount of metal, the method

3 comprising :

4 a) utilizing a site-existing predetermined pathway between the

5 designated area and a connected area, the pathway comprising a traffic zone having

6 a size for accommodating passage through the pathway;

7 b) installing a metal detector for detecting the threshold amount of

8 metal passing through the traffic zone, comprising installing the metal detector in a

9 location which does not restrict the size of the traffic zone within the pathway, but in

10 which the nature of the pathway appropriately positions the source of metal in a i i detection zone relative to the metal detector for effectively searching the source for

12 the threshold amount of metal;

13 c) monitoring for an attempt to pass through the detection zone with

14 at least the threshold amount of metal and providing information regarding such an is attempt to a means adapted to respond to the attempt; and

i6 d) physically preventing access to or egress from the designated area

17 by the source of the threshold amount of metal.

1 2. The method of claim 1, wherein the site-existing predetermined

2 pathway comprises a barrier for controlling passage through the pathway, wherein

3 the metal detector is positioned to detect the threshold amount of metal prior to

4 passage of the source past or through the barrier; and wherein the response to the

5 attempt to pass through the detection zone with at least the threshold amount of

6 metal comprises disallowance of passage past or through the barrier.

1 3. The method of claim 2, wherein the barrier comprises a door

2 having an automatic lock/unlock system.

i 4. The method of claim 2, wherein the predetermined pathway

2 comprises an industrial pathway and the barrier comprises means for removing a

3 source of metal from the industrial pathway.

1 5. The method of claim 1, wherein the predetermined pathway

2 comprises an industrial pathway, the means adapted to respond comprises a marker

3 for marking the source with an identifier, and the step of preventing access or egress comprises physically removing the source marked with the identifier from the industrial pathway.

6. The method of claim 1, wherein the metal detector is concealed or disguised to provide surreptitious monitoring.

7. The method of claim 6, wherein the metal detector further comprises remote signaling capability and the step of preventing access or egress comprises receiving a signal from the metal detector and physically disabling progress of the source of metal.

8. The method of claim 1, wherein the predetermined pathway is capable of supporting vehicular traffic, and the metal detector is adapted to detect passage of vehicles.

9. The method of claim 1, wherein the response comprises providing an audible signal indicating detection of the threshold amount of metal.

10. The method of claim 1, wherein the source comprises a person carrying the threshold amount of metal and the means adapted to respond comprises means for providing information to the person suggesting a potential action.

11. The method of claim 1, wherein the means adapted to respond comprises means for providing a visible signal.

12. The method of claim 11, wherein the visible signal communicates information about an amount of metal detected.

13. The method of claim 11, wherein the information about the amount of metal detected includes information relating to exemplary weapons corresponding to the amount of metal detected.

14. A system for utilizing a site-existing pathway for monitoring access to or egress from a designated area by a source of metal, the system comprising :

one or more field coil modules adapted for placing in a relationship to a pre-existing physical barrier having means for controlling passage through the barrier in a location which does not restrict the site-existing pathway, but which utlilizes the pathway to appropriately position the source of metal in a detection zone relative to the one or more field coil modules for effectively searching the source for the metal 9 and detecting the source of metal prior to passage of the source past or through the

10 barrier;

i i a power supply module interconnected with the one or more field coil

12 modules; and

13 an electronics module interconnected with the one or more field coil

14 modules and the power supply module, the electronics module adapted to receive is and process an electrical signal from the one or more field coil modules, to indicate if

16 metal is detected, and optionally for activating means for responding to the source of

17 metal.

1 15. The system of claim 14, wherein the field coil module comprises

2 a single, portable field coil module that is adapted to be rolled or folded for transport

3 and storage when not in use.

1 16. The system of claim 14, wherein the field coil module comprises

2 a transparent casing which encloses one or more field coils.

1 17. The system of claim 14, further comprising means for

2 responding comprising means for controlling passage through the barrier.

1 18. The system of claim 17, wherein the means for responding

2 comprises an automatic door lock/unlock system.

1 19. The system of claim 14, comprising an indicator for signaling

2 when a threshold amount of metal is detected, the indicator comprising an audible

3 indicator, a visual indicator, or a combination thereof.

1 20. The system of claim 14, wherein the site-existing pathway

2 comprises an industrial pathway wherein the physical barrier comprises means for

3 removing the source of metal from the pathway upon detection of at least the

4 threshold amount of metal.

1 21. The system of claim 20 further comprising a marker for initially

2 marking the source of metal to facilitate later removal of the source from the

3 pathway by the means for removing the source.

1 22. The system of claim 14 in which the physical barrier is a door,

2 the system comprising at least one field coil module placed above the door to create

3 a detection zone in front of the door.

23. The system of claim 14 in which the physical barrier is a door, having a floor in front of the door, the system comprising at least one field coil module placed on or in the floor in front of the door to create a detection zone in front of the door.

24. The system of claim 14 in which the physical barrier is a door, having a floor in front of the door, the system comprising at least one field coil module placed on or in the floor in front of the door and one field coil module placed above the door to create a detection zone in front of the door.

25. The system of claim 14 in which the physical barrier is a door, wherein the one or more field coil modules comprise at least one appendage mounted alongside the door and projecting out into a space in front of and alongside the door to create a detection zone in front of the door.

26. The system of claim 28, comprising two appendages, one on each side of the door.

27. A system for monitoring access to or egress from a designated area by a source of metal utilizing a site-existing pathway for supporting vehicular or pedestrian traffic, the system comprising:

one or more field coil modules adapted for placing in a location which does not restrict the pre-existing pathway, but which utlilizes the pathway to appropriately position the source of metal in a detection zone relative to the one or more field coil modules for effectively searching the source for the metal;

a power supply module interconnected with the one or more field coil modules;

an electronics module interconnected with the one or more field coil modules and the power supply module, the electronics module adapted to receive and process an electrical signal from the one or more field coil modules, to indicate if metal is detected, and to send a remote signal to means for receiving the signal, the signal indicating a presence or absence of vehicular or pedestrian traffic carrying the threshold amount of metal within the pathway, wherein the field coils module, power supply module, electronics module, and means for sending the remote signal are integrated into a single unit that is concealed or disguised to minimize detection by persons in the predetermined pathway.

1 28. The system of claim 27, wherein the field coils module, power

2 supply module, electronics module, and means for sending the remote signal are

3 disguised as a discarded item or a naturally occurring object.

1 29. The system of claim 27, comprising at least two metal detectors

2 spaced a known distance apart and a processor for calculating speed of transit

3 between the two metal detectors.

1 30. A system for indicating presence of an object having a threshold

2 amount of metal in a pre-existing space for the object, the system comprising :

3 one or more field coil modules adapted for placing in a location which

4 does not restrict the pre-existing space, but which utlilizes the pre-existing space to

5 appropriately position the source of metal in a detection zone relative to the one or

6 more field coil modules for effectively searching the source for the metal;

7 a power supply module interconnected with the one or more field coil

8 modules;

9 an electronics module interconnected with the one or more field coil lo modules and the power supply module, the electronics module adapted to receive i i and process an electrical signal from the one or more field coil modules, to indicate if

12 metal is detected, and to send a signal indicating presence or absence of the object in

13 the pre-existing space.

1 31. The system of claim 30, wherein the pre-existing space

2 comprises a parking spot for a land vehicle or a docking slip for a water vehicle.

1 32. The system of any of claims 14, 15, 22, or 30, wherein the one

2 or more field coils modules comprise a transmitter coil and a receiver coil placed on

3 opposite sides of the pathway.

1 33. The system of any of claims 14, 15, 22, or 30, wherein the

2 transmitter coil and the receiver coil comprise a single integrated unit placed on a

3 single side of the pathway.

1 34. A method of providing metal detection technology in a format

2 readily usable by consumers, the method comprising providing a family of metal

3 detection modules adapted for interconnection with one another in a plurality of

4 potential combinations, each combination comprising at least one field-coil module

5 adapted to be installed in a site-existing pathway, at least one electronics module,

6 and at least one power supply module.

35. The method of claim 34 further comprising providing a plurality of output devices adapted to be interconnected with the at least one electronics module.