The present invention relates generally to a method and apparatus for monitoring the security of closures of the type used on large trucks, and shipping or other containers wherein one or more doors are provided on an end and/or the sides of the container and are secured by vertical rods having cam-like latches at their ends that are rotatable from a first disposition in which they engage keepers to lock the doors in a closed position, and a second disposition in which they disengage the keepers to unlock the doors and allow them to swing into an open position. More specifically, the present invention relates to a monitoring assembly that attaches between the locking rod handles of the containers, senses any movement of the locking handles or the opening of the doors, and provides visual signals and/or transmitted signals as an indication of tampering.
Many types of anti-tamper locking and detection schemes and monitors are known in the prior. Notable among disclosures of such apparatus are those disclosed in the U.S. Patent Applications of Publications of Terry et al No. 20090146437 entitled “Reusable locking body, of bolt-type seal lock, having open-ended passageway”; Dobson et al No. 20090135015 entitled “Locking apparatus for shipping containers”; Terry et al No. 20090127873 entitled “Bolt-type seal lock having separate housing, connected to locking body, with electronics for detecting and wireless communicating cutting of bolt”; Evans et al No. 20090102660 entitled “Method and Apparatus for Tracking and Monitoring Containers”; Diener et al No. 20090102652 entitled “Apparatus for Detecting Tampering with a Latch Mechanism”; and Dixon et al No. 20090058711 entitled “Method and system for monitoring security of containers”. However, most such container monitors are very expensive, use substantial power and are very bulky and their powered life is quite short. Simple locking mechanisms do not have history recording features, and visible displays are quite limited and the viewer must be quite close to see them.
Briefly, a preferred embodiment of the present invention relates to a method and apparatus for monitoring the security of doors used on shipping or other containers wherein the doors exist at one end and/or on the sides of the container as two closures secured by vertical rods having cam-like latching mechanisms on their ends that engage keepers on the container allow the doors to swing open and one or more handles must be rotated to allow entrance into such containers. The apparatus attaches between the locking rod handles of the vertical rods and senses the opening of the doors or movement of the locking handle. The sensing of tamper activity is logged into an electronic memory, and indication is made with a highly visible display that changes from GREEN to RED to indicate that tampering has transpired. Further, a Radio Frequency Identification Device (RFID) device and radio circuit can be alerted as to the presence of the tampering, and in response, proper alarming action is started. Further, a localized micro-processor can act on the tamper status in several ways. Further, the micro-processor can be programmable to sense optional temperature, radiation, shock, bio-activity or other events and perform tasks accordingly. The monitor so developed can be made to be a one-time-use device and as such is disposable. The unit is self contained and battery powered.
The present invention provides a new method and apparatus for detecting the tampering of doors of shipping containers using a very inexpensive micro-processor based architecture that senses the movement of closure handles and allows the status of such tamper events to be displayed in an effective and highly visible way. The attachment of this tamper evident device is quite simple and the life of the electronics is set for at least 60 days of monitoring. Various sense ports allow different auxiliary monitoring functions, and a memory provides time information in the form of a tamper or status histogram. The addition of an RFID tag allows remote monitoring, and the electronics are capable of relaying information through an RF transmitter to allow wireless status information to be read at a remote location.
The present is embodied in a disposable unit having a highly visible tamper evidence display. It is battery operated, has a long 60 day service life and mounts as a single unit on variant dimensioned doors in just a few seconds. It is fully tamper-proof and utilizes unique serial numbers and means to avoid replication. It generates a histogram of time and tamper that is placed into electronic memory. The system employs fiber optic sensed loops for environmental robustness and has night-time and day-time status indication and RFID and bar-code identifiers.
The present invention also has application in the monitoring of other types of doors or enclosures; for example, anywhere a GREEN (GO) or a RED (STOP) status needs to be displayed. It could be used for temperature monitors, fire alarm displays, mechanical controls, environmental status indicators or a myriad of other applications where a relatively long term monitoring activity is needed.
IN THE DRAWING
Referring to the simplified showing in
It is an intent of a first embodiment 30 of the invention shown in
This embodiment features a unit that will clasp onto the handle carrying rod 18 as indicated in
The unit 30 provides a sophisticated and low cost electronic monitor for the shipping container industry. Its functionality includes the ability to monitor several door opening and tamper points on most standardized containers, and to annunciate a breach into the container's door closure.
The unit 30 is battery powered and operates for up to 60 days while the container to which it is affixed is in storage and/or transit. With its resident microprocessor, the unit keeps track of time during the installed period and records the time event of any breach condition. Breach monitoring is accomplished using unique, high technology means including special sensors that are highly immune to faults from environmental conditions, vibration and aging. Multi status display techniques are utilized that include a visual red and green color changing panel, colored lights, sound and a radio architecture that sends alarm status remotely. The unit offers optional RFID communications per standards that meet the requirements of the International Organization for Standardization.
As depicted in
The locking “CLIP” design, depicted in its unlatched and open configuration in
As illustrated in
A feature of this embodiment of the present invention is the color changing a GREEN to RED STATUS change in a DISPLAY MODULE 40. This technology is disclosed in detail in U.S. Provisional Patent Application Ser. No. 61/140,815 filed on Dec. 24, 2008, entitled “Multiple Interlaced Display Using Windowed Sheets”, by Victor Ivashin and Heather Ivashin, and such disclosure is expressly incorporated herein by reference. The Display allows interlaced sheets of colored material to slide relative to each other and through slits to form color fields that change when a slider is activated. See
The DISPLAY MODULE 40 includes a plastic housing 42 that contains the working slide mechanism 44 described in the cited invention disclosure. This DISPLAY MODULE is a component in the present embodiment, and the activation of a slider to make the transition of the GREEN to RED state is under the control of a spring loaded PULL that un-meshes the interleaved GREEN and RED color sheets 46 and 48. As suggested by the showing in
As suggested above, the mechanical visual display component is implemented as a module including multiple components (as can be seen in
The Nitinol Wire is activated (shrinking in length) when an electric current is passed through it, heating the wire. This releases the PAWL. An O-Ring is used to provide a loading force on the PAWL to keep it engaged with the tooth of the PULL. The PAWL rotates to release the PULL.
As will be further explained below, each of the GREEN to RED STATUS Displays is serialized with one of 1.6 million different numbers to match two other similar labels on the main enclosure and “CLIP” of the unit. The serial tags are printed on a reflective holographic surface. Further, they provide a release agent that divides the label into patterned and broken sections if an attempt is made to remove them, this proving a tamper revealing feature. This insures unit-to-unit uniqueness as the three serial number labels must match; the label on the GREEN to RED STATUS Display, a label on the main enclosure, and a label on the “CLIP” (the hinged portion that grabs the vertical locking rod). The labels carry at least 4 alpha-numeric characters that change per unit. Each character's attribute is hence from a set of 36 (26 alpha+10 numeral) possibilities. This allows 364 combinations.
The GREEN to RED STATUS Display is visible from at least 100 feet away and a simple, all GREEN STATUS panel depicts an un-tampered container closure while a RED STATUS panel indicates that a tamper or entrance event has occurred. The GREEN STATUS further has a holographic reflective (mirror) silver matrix sheet that acts as a “MID” sheet to deter replication. See
The entire GREEN to RED STATUS Display is shielded at the frontal exposure by a LENS piece of tempered and hardened glass so that any intrusion or tamper event will result in highly visual broken glass. Tempered glass shatters into many pieces and the tamper event becomes obvious.
As shown in
The high impact plastic enclosure for the unit is designed to withstand harsh environmental conditions and is waterproof and temperature tolerant. All access to the inside has been disabled and several of the components are hermetically sealed. The unit can operate within the −40° C. to +75° C. range defined in the ISO standards.
The rotational movement of the vertical locking rod of the container (that includes the primary access handle and door locking cam or latch) is monitored using three separate sensing techniques and devices.
As shown in
The second sensing technique is within the design of the “CLIP”, the grasping portion of the enclosure. Once rotated into place as depicted in
When the GLASS ROD 60 is broken, or the “CLIP's” circuit paths are opened, the alarm is set, the GREEN STATUS Display 40 becomes RED, and the RED STATUS light 52 is illuminated. Further, by option, and if implemented, radio alarming pulses will be generated, the RFID device will be activated, and the microprocessor will record the time of this event. Another action may also be programmed in response to the alarm.
The third sensing technique is a visual one. Referring again to
As depicted in
Neither the right side DOOR nor the left side DOOR of the container can be opened without violating this RED SENSE LOOP or removing the unit. Either of these events trigger a RED STATUS alarm.
When the RED SENSE LOOP circuit path is violated, the alarm is set, the GREEN STATUS Display becomes RED and the RED STATUS light is illuminated. Further, by option, and if implemented, radio alarming pulses are generated, the RFID device will become activated, the microprocessor will record the time of this event, or another action may be programmed to respond to the alarm condition.
As is shown in
An industry accepted bar code label can also be applied as an optional way to remotely scan in the serial number of the unit; the number representing a way-bill number, a container tracking number, shipment reference number or some other number of importance to the user of the container.
The self-contained batteries used in the unit are housed in a special Power Module that is removed and recycled after the container has reached its destination. The Power Module becomes functional only when the unit is placed onto a container's vertical pole as contacts on the Power Module engage into a receptacle only after the CLIP 33 is firmly seated onto a vertical locking rod 18. The batteries are based on state-of-the-art lithium technology which allows 120 days of storage prior to the 60 days of armed operation. An expiration date is stamped on the Power Module, providing awareness as to the service life. The batteries may be of variant form and voltage depending on the application.
The disclosed embodiment has been designed to permit ease of attachment. When received, the unit is taken out of its shipping package in a factory preset state with the CLIP portion already opened and ready to be attached to a container's vertical locking rod. At this time, the unit is inactive electrically in that the Power Module has been placed in a shipping orientation, providing no power to the unit. The RED SENSE LOOP cable is now placed around the container's secondary door locking rod 16 (LEFT DOOR) and looped back on itself to provide a hold. This action requires the unit to be “threaded through” the loop after the loop is wrapped about the vertical locking rod 16.
By pushing the Power Module (
After 30 seconds, the GREEN STATUS Display will commence with the GREEN light flashing at its set rate, completing the attachment and arming procedure.
At the end of the transit, the unit is removed by simply pulling the handle of the locking rod and opening the door. The indicating COMB 66, the GLASS ROD 60 and the connective straps 62 will break away under the pressure of the door handle. The RED STATUS will appear and the unit can be removed from the locking rod. The batteries will continue to operate the unit in ALARM condition for up to 60 days from the time the unit was energized. If the unit is not to be interrogated for data, the user must remove the Power Module and re-cycle it according to the directions printed on the label of same. A pull handle is provided to remove the Power Module. The plastic enclosure and the rest of the unit, without batteries, is RoHS compliant and can be re-cycled. The unit is a one-time-use monitor.
At the end of the transit period, the unit may be interrogated for data. This requires use of the RFID architecture described below. When the unit went into RED ALARM mode, or another monitored condition, data was stored within the micro-processor's non-volatile memory and simultaneously made available to the RFID portion of the design. This data is preserved even after the power is removed, and through RFID interrogation can be extracted from the unit by an external read device.
The microprocessor electronics feature a knowledge of all power up, monitor and power down cycles, and are so configured as to permit them to occur only once. When an ALARM or other condition is sensed, proprietary circuits alter the unit to not allow a subsequent event sense operation. The GREEN STATUS state can only occur once, even if the electronics is recovered and forced to power-on again. All microprocessor commands are coded and scrambled. This is a sophisticated type of “electronic fuse” that protects the architecture from being copied or the unit used again.
For a visual summary of the main parts of the unit when in position on a container locking pole, see
As illustrated in
Various techniques and assemblies were experimented with before arriving at the above described preferred embodiment. However, it is important to note that there are other variations of hardware that may be likewise be used to implement the present invention. Similarly, other variant materials may be used to accomplish the goals set forth in this disclosure.
The use of specialty plastics to accommodate the wide temperature extremes into which the unit is exposed is an important consideration. Nylon was used whenever possible, and the anticipation of strength reinforced ABS and PVC was also considered. The above described implementation of the invention is not limited to use of any of the specific materials described above.
The basic operation of the unit revolves around the elements and circuit illustrated in
The Analogue Heart Beat Unit A, is an oscillator that provides a clock that is apart from any clocking in the micro-processor and provides a pulse that has a period of approximately one second and a pulse width that is 15 milliseconds long in its active state. These pulsed signals are routed to Block C and Block D, which are respectively, the drivers for the RED and GREEN LEDs described above. The output of Block A is also routed to the INT interrupt line of the Micro-processor E, to act as a timing co-ordinator. The output of Block A is also routed to the Delay Line Pulse Train unit J, and used to sequence a state machine delay line. The oscillator of Block A can be constructed to be of variant type, although a Schmidt trigger feedback oscillator was implemented in the described embodiment. Relaxation, Hartley, Colpitts, divided down crystal oscillators or other types of oscillators can alternatively be used. The oscillator of Block A runs continuously during operation of the unit.
The RED-GREEN FLIP-FLOP B, is a bi-stable latch that is reset upon power-up and controls and enables the two LED drive circuits in Blocks C and D. This flip-flop sets the status state of the unit to be either the GREEN safe state or the RED alarm state. When reset, the RED-GREEN FLIP-FLOP is in the GREEN state and enables the GREEN LED D circuit to flash at the rate given it from the Block A circuits. The RED-GREEN FLIP-FLOP B can also be controlled by the Micro-processor E, to be held off, to be set or to be reset. As the Micro-processor determines the alarm condition(s), it can hence set or reset the RED-GREEN FLIP-FLOP which of course enables either the GREEN or RED LED circuits.
Block C is the driver for the RED LED and is basically a charge pump and transistor driver that is gated by the correct term from Block B. When the RED-GREEN FLIP-FLOP is reset, Block C is disabled. When enabled, this circuit flashes the RED LED at the rate of the Block A clock for the active time of 15 milliseconds.
Block D is the driver for the GREEN LED and is basically a charge pump and transistor driver that is gated by the correct term from Block B. When Block B is set, Block D is disabled. When enabled at reset, this circuit flashes the GREEN LED at the rate of the Block A clock for the active time of 15 milliseconds.
The Micro-processor E accomplishes several functions that relate to the operation of the unit including control decisions that accomplish the following:
The Micro-processor E has all of its operational memory, including the operating code, the temporary registers and storage, the registers for update and history and the working random accessed memory in the form of flash memory. This means that certain values will survive even in the event of a loss of power. Further, the code (program) memory is down-loaded through a serialized pin format during initial manufacture.
After reset (power-up), the Micro-processor E must hold all of the error processing and indication in a frozen state until the person placing the unit on a container is finished latching it into place. This process may take a minute or two and the Micro-processor E will use its hold-off logic to keep the RED-GREEN FLIP-FLOP B from setting to the RED status during this interval.
Once the unit has been attached and enabled, it is the duty of the Micro-processor E to receive signals on its INT line, showing that the clock circuits are functioning and to resultantly output a toggle pulse to the INDEPENDENT WATCH_DOG H to keep its counter from over-running. The WATCH_DOG H is tasked with observing the proper operation of the Micro-processor, and if the Micro-processor cannot supply it with regular pulses, an error condition will result with the assertion of the RED status.
Another function of the Micro-processor E is to allow current to flow into the PULL wire for the transitioning of the GREEN to RED Display module. This is a single pulse that occurs when the unit goes into a RED status, and at this time the Micro-processor must program a byte in its memory to indicate that a RED status has occurred. This byte is then looked at during every power-up operation to immediately be the flag that places the unit into a RED status.
Still another function of the Micro-processor E is to examine the status of the peripheral light pipe (GLASS ROD) loop and determine whether the signals are still passing through the loop. And if not, to instigate a RED status.
A further function of Micro-processor E is to examine the status of the peripheral wire LOOPS (in the CLIP) and to determine whether or not the signals are still passing through the loops. And if not, to instigate a RED status.
Yet another function of Micro-processor E is to examine the status of the peripheral wire RED WIRE LOOP (at the LEFT DOOR vertical locking rod) and to determine whether or not the signals are still passing through the loop. And if not, to instigate a RED status.
From the time the unit is enabled on the shipping container, or other application, a record of past time must be kept and the Micro-processor E can accomplish this in two ways. The Micro-processor has a crystal oscillator that runs its timing, and as such it can accurately count real time into a register that stops accumulating at will or at the time of a first tamper. The register will have a histogram of the required time lapse. Another time keeping function is to count the number of INT pulses that come from the Block A. This may not always be the most accurate time keeping record, however, as the Block A circuit is derived from an analogue oscillator without conventional crystal or tuned accuracy.
Also stored in the histogram will be the identity of the event that transpired to make the unit record a tamper or security breech event.
Also stored into the Micro-processor's flash memory will be the various serial numbers, freight numbers, codes, container numbers, way-bill records and customer names which may also include primary shipping information that relates to origin and source. The serial number of the unit is also stored in the Micro-processor's flash memory.
Micro-processor E has the ability to transfer data in the flash memory (including all constants and variables) to an RFID, or other peripheral device having a four wire Serial Peripheral Interface Bus (or SPI bus).
The QUAD DRIVER F is a logic element in the 74xx244 family of logic that allows the multiplexing of two sets of 4 lines from the rest of the logic to and from the Micro-processor. Four lines are input and 4 lines are output. A controlling term from the Micro-processoror switches the enabling of each group of four using 4 input-output peripheral lines of the Micro-processoror.
The four inputs are:
The four outputs are:
The DISPLAY PULL WIRE G is a circuit that is designed as a driver transistor that activates current into the GREEN-to-RED Display's nitinol PULL wire as discussed above. When a situation causes the RED status to appear, the Micro-processor E will activate this circuit. The circuit for the PULL wire can also be activated by the WATCH_DOG H timing out. The WATCH_DOG circuit is normally reset at intervals under control by the Micro-processor, and should a failure exist within the Micro-processor, the WATCH_DOG H will activate the DISPLAY PULL WIRE G. A timing circuit in the DISPLAY PULL WIRE G activates the PULL nitinol wire for 4 seconds and then disables the circuit. This is done to reduce current in the system after the condition goes towards a RED status.
The WATCH_DOG circuit is normally reset at intervals under control by the Micro-processor, and should a failure exist within the Micro-processor, the WATCH_DOG H will activate the DISPLAY PULL WIRE G. The WATCH_DOG is basically a running counter that has a full cycle time on the order of 2 to 4 seconds but can be reset by an external signal, herein being provided by the Micro-processor E on a regular interval of slightly over one second. All is fine as long as the Micro-processor provides the pulses to keep clearing the counter. When the pulses are absent and the counter over-runs, the design flags this as a failure in the Micro-processor for whatever reason. The WATCH_DOG H then sets the RED-GREEN FLIP-FLOP (setting the RED alarm status state) and activates the DISPLAY PULL WIRE G. This action sets the RED status state which locks out any indication of the GREEN status. The WATCH_DOG H is a single integrated circuit and is available in many time periods from many manufacturers.
The DELAY LINE PULSE TRAIN J receives the master clocking signal from the Block A, this being a 15 millisecond pulse at intervals of 1 or more seconds and time shifts the signals 3 times through the use of resistive-capacitive (integration) networks. This establishes delayed pulses that form a sequence which will be used to progressively scan the 4 input-output conditions that need to be examined and acted upon to create the known status of the system. Each of the pulses created is identical but delayed an increment of time.
The IR LOOP PULSE T/R K is a logic and driver module that when activated will place a pulse towards an infra-red LED that transmits the resultant light pulse through the GLASS ROD loop that exists to monitor the RIGHT HANDLE of the unit. A pulse returning indicates all is well. Simultaneous with creating the pulse of light a flip-flop is set within the block that may be reset when the light returns. A decision block then either validates the return or sets an error named -IR ERR which will be sent back to the Micro-processor E for decisive processing. The first of the pulses coming from the DELAY LINE J will be used to establish the time for this “scanning”.
The Wires on Red Cable T/R L is a logic and driver module that when activated will place a pulse towards a current generator that transmits the resultant current pulse through the RED WIRE loop that exists to monitor the LEFT vertical rod attachment of the unit. A pulse returning indicates all is well. Simultaneous with creating the current pulse a flip-flop is set within the block that may be reset when the light returns. A decision block then either validates the return or sets an error named -REDWIRE ERR which will be sent back to the Micro-processor E for decisive processing. The second of the pulses coming from the DELAY LINE J will be used to establish the time for this “scanning”.
The Wires on CLIP T/R M is a logic and driver module that when activated will place a pulse towards an current generator that transmits the resultant current pulse through the CLIP LOOP wires that exists to monitor the attachment to the RIGHT vertical locking rod of the unit. A pulse returning indicates all is well. Simultaneous with creating the current pulse a flip-flop is set within the block that may be reset when the light returns. A decision block then either validates the return or sets an error named -CLIP ERR which will be sent back to Micro-processor E for decisive processing. The third of the pulses coming from the DELAY LINE J will be used to establish the time for this “scanning”.
The AUX T/R N is a logic and driver module that when activated will provide a gating pulse to auxiliary logic that may exist on a peripheral printed circuit board. A digital pulse returning indicates all is well. Simultaneous with creating the gating pulse a flip-flop is set within the block that may be reset when the peripheral circuit responds. A decision block then either validates the return or sets an error named -AUX ERR which will be sent back to Micro-processor E for decisive processing. The fourth of the pulses coming from the DELAY LINE J will be used to establish the time for this “scanning”.
The ACOUSTIC DEVICE O is a piezoelectric transducer that is activated through a base-driven transistor with the piezoelectric element in the collector circuit. A signal from the Micro-processor named -BEEP will activate this circuit. This signal may be asserted under program control.
The RFID and RF Interface P is a connector that has been set for the deployment of a future RFID device and/or logic. Basically the various important control terms have been brought out to this Interface allowing the Micro-processor E, the WATCH_DOG H and the AUX T/R N portions of the architecture to communicate with this block.
The operation of the inverter Q is to control the gates and drivers used by the Micro-processor to switch the 4 input/output lines from receivers to transmitters, enabling the QUAD DRIVER F to drive or receive signals. A digital logic term from the Micro-processor, -A/B, controls the selection.
The FF R represents an auxiliary flip-flop latch that may be set and reset by Micro-processor E for use by the AUX T/R N. It provides an extra selection term for any logic that may be required in the AUX T/R N at a future date. This flip flop FF R is set where the -BEEP term is asserted, and reset when the -SET DOG/AUX logic term is asserted by Micro-processor E.
The Reset S is a commercial integrated circuit designed to output a reset pulse. At power-up, this block provides 300 to 600 milliseconds of an active low reset signal. The reset signal will be used to reset Micro-processor E, the RED-GREEN FLIP-FLOP B and the peripheral port RFID and RF Interface P.
The Battery Sense, Block T, is a commercial integrated circuit designed to output a logic signal whenever the battery or Vcc voltage falls below a certain value. This is essentially a form of reset signal and will be directly placed into the Micro-processor where a decision will be made as to whether or not to set the RED-GREEN FLIP-FLOP B, to power down or to allow Micro-processor E to go into a “sleeping state”. In the proto-type the battery voltage was at 3 volts and the circuit used for the Battery Sense Circuit T was set for an alerting signal at 1.8 volts.
The basic operational function of Micro-processor E is portrayed by the flow diagram of
In
In
In
In
In
This embodiment of the invention differs from the first above described embodiment in both mechanical detail, as described above, and in electrical detail. Signal handling changes have been implemented in this alternative embodiment to simplify the design of the micro-processor and the logic that surrounds it and those changes are described herein.
A change was made to the WATCH-DOG circuit to allow the circuit to time out to toggle a flip-flop, that flip-flop being responsible for the activation of the nitinol wire in the GREEN to RED Display. The flip-flop sets to activate the wire and resets from a feedback path from a contact on the wire itself that signals the completion of the wire PULL to change the Display from GREEN to RED.
The Micro-processor was changed and selected to be a SiLabs C8051F920-GM, having a wide selection of I/O and internal analogue capabilities.
All LEDs in the design have been configured to work from an accumulative charge pump circuit. These micro-processor controlled transistors will pump twice the working Vcc voltage onto a capacitor and the micro-processor controlled charge will be placed across the two LEDs for GREEN and RED annunciation (one at a time) as well as for four sequenced LEDs that are utilized to place pulses onto the fiber optics that are now an integral part of the sensing circuits in the unit. The micro-processor can now selectively power the anodes of any of the 6 LEDs by activating transistors that provide current to the LED anodes and by then scanning the depletion of the voltage on the capacitor and one of the analogue inputs of the micro-processor. This optimizes the ON time of the LED selected. All the LEDs are sequenced one at a time and the RED and GREEN front panel LEDs are on for times in the milli-seconds range while the other fiber optic source LEDs are typically on for only a few microseconds.
All LEDs in the design that are not the two GREEN and RED visible front panel LEDs pulse into optical fiber pipes that eventually all converge onto two photo-receptors identified as SENSORS in the diagram of
The basic BLOCK DIAGRAM has also been changed to make all peripheral sensing fiber optic based. This means that the CLIP on the RIGHT DOOR, the sensing of the LEFT DOOR vertical rod attachment and the GLASS ROD LOOP are all using fiber optical cable as the serial looping technique. The PRISM COUPLERS allow the transition between the inner and outer enclosures and provide a way to allow loops to move and still pass light.
As alluded to above, plastic PRISMS allow the transition between zones and between moving members of the fiber cable that must couple with each other. Such PRISMS are shown in the schematic diagram of
The GENERAL FIBER CABLING is shown in
Although we have thus disclosed what we believe to be two optimal embodiments of the present invention, it is anticipated that other alternatives will become apparent to thus skilled in the art and having read this disclosure. It is therefore intended the this disclosure be considered a general teaching and that the scope of the protection afforded will be limited only by a fair interpretation of the claims appended hereto.
This patent application claims the benefit under 35 USC 119(e) of U.S. Provisional Patent Application No. 61/140,820, filed on Dec. 24, 2008 and entitled “Security Monitor for Doors”, and U.S. Provisional Patent Application No. 61/140,815, filed on Dec. 24, 2008 and entitled “Multiple Interlaced Displays Using Windowed Sheets”, the disclosures of both applications being expressly incorporated hereinto by reference for all purposes.
Number | Date | Country | |
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61140820 | Dec 2008 | US | |
61140815 | Dec 2008 | US |