Patent Application
20070080802
This invention relates to security and alarm systems, and in particular to devices for monitoring opening of a closure.
It is often desirable to secure doors, access hatches, gates, containers and other closures to prevent and/or detect unauthorized opening thereof. Traditional methods for preventing unauthorized opening of closures involve the use of locks. However, locks have the drawback of requiring the user to carry a key or memorize combination sequences. Further, locks are susceptible to undetected tampering if unauthorized persons remove the lock, gain access to the closure, and re-attach the lock.
It is also desirable to provide means for preventing un-authorized access to fuel contained within fuel tankers. Unauthorized persons may not only steal the fuel, but may also replace the contents with water or some other liquid, in order to make the liquid level appear correct at the final destination. When a fuel tanker reaches its destination, the contents of the tanker would normally be added to a larger reservoir, thereby contaminating the entire reservoir. Thus, there is a need for intrusion detection devices that can provide a warning if there has been unauthorized access to the contents of a fuel tanker.
Optical and other types of sensors are sometimes used on vehicles such as fuel tankers in order to monitor fluid levels in the tanker. However, in some instances, unauthorized users may remove the sensor in order to siphon fluid from the tanker through the resultant opening. There is therefore a need for a device capable of monitoring such sensors, in order to provide a warning if someone removes or tampers with the sensor.
U.S. Pat. No. 5,831,531 to Tuttle discloses an example prior art system which incorporates a trip-wire or magnetic circuit associated with a container. If continuity of the circuit is disabled by a forced entry into the container, electrical detection means alert the owner or a monitoring station.
There remains a need for robust devices capable providing an indication that a closure has been accessed.
The following embodiments and aspects thereof are described and illustrated in conjunction with systems, tools and methods which are meant to be exemplary and illustrative, not limiting in scope. In various embodiments, one or more of the above-described problems have been reduced or eliminated, while other embodiments are directed to other improvements.
One aspect of the invention provides a device for monitoring opening of a closure. The device comprises a securing element and a switch assembly. The switch assembly comprises a switch and an opening positioned to receive the securing element. The switch is configured to be in a first position when the securing element is inserted into the opening and in a second position when the securing element is not inserted into the opening. The closure cannot be opened while the securing element is within the opening of the switch assembly.
Another aspect of the invention provides a method for monitoring opening of a closure having first and second portions which are moveable with respect to one another to allow access to an area secured by the closure. The method comprises providing a device comprising a securing element and a switch assembly including a switch and an opening positioned to receive the securing element, the switch configured to be in a first position when the securing element is inserted into the opening and in a second position when the securing element is not inserted into the opening, attaching the securing element to the first portion of the closure, attaching the switch assembly to the second portion of the closure, and, inserting the securing element into the opening of the switch assembly, such that the closure cannot be accessed without removing the securing element from the opening of the switch assembly.
Another aspect of the invention provides a method for monitoring opening of a closure having first and second portions which are moveable with respect to one another to allow opening of the closure, and locking means for holding the first and second portions of the closure in a closed position. The method comprises providing a device comprising a securing element and a switch assembly including a switch and an opening. positioned to receive the securing element, the switch configured to be in a first position when the securing element is inserted into the opening and in a second position when the securing element is not inserted into the opening, and, inserting the securing element through the locking means and into the opening of the switch assembly, whereby the closure cannot be accessed without removing the securing element from the opening of the switch assembly.
In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the drawings and by study of the following detailed descriptions.
Example non-limiting embodiments are illustrated in the appended drawings. It is intended that the embodiments and figures disclosed herein are to be considered illustrative rather than restrictive.
In drawings which illustrate non-limiting embodiments of the invention:
Throughout the following description specific details are set forth in order to provide a more thorough understanding to persons skilled in the art. However, well known elements may not have been shown or described in detail to avoid unnecessarily obscuring the disclosure. Accordingly, the description and drawings are to be regarded in an illustrative, rather than a restrictive, sense.
A tamper and intrusion detection device for securing a closure comprises a securing element such as a bolt, and a switch assembly. The securing element may be rigid or semi-rigid. The securing element is inserted into an opening of the switch assembly. The securing element may have a threaded end which is received in a threaded hole. The threaded hole which receives the securing element may be located either in a mounting bracket to which the switch assembly is secured, or in a threaded hole in a face plate of the switch assembly. The switch assembly may define an opening and comprise a switch located in the opening. The securing element closes the switch of the switch assembly when the securing element is received in the opening of the switch assembly. The switch assembly is connected to a control circuit which produces a first indication when the switch is closed and a second indication when the switch is open.
The closure may comprise first and second portions which are moveable with respect to each other to open the closure. The securing element may be secured to one portion of the closure and the switch assembly may be secured to the other portion of the closure, such that the closure may not be opened without removing the rigid element from the switch assembly. In situations where the closure comprises locking means, the securing element and the switch assembly need not be secured to the closure, and may be inserted through the locking means and into the opening of the switch assembly, such that the locking means may not be opened without removing the securing element from the switch assembly.
Momentary switch 32 includes a push-button 34, which closes a contact 36 when depressed. Closure of contact 36 completes a circuit comprising conducting wires 38. Push-button 34 is spring-loaded, and returns to an open (i.e. non-conducting) state when not depressed. When inserted through hole 16 in mounting bracket 20, bolt 12 depresses push-button 34, which allows current to run through conducting wires 38.
Removal of bolt 12 from switch assembly 30 allows button 34 to return to the open state. Return of push-button 34 to the open state opens contact 36, such that the circuit comprising conducting wires 38 is broken. Breaking of the circuit comprising conducting wires 38 results in the creation of an alarm condition. An alarm condition may be detected by an alarm controller 40 (see
Alarm controller 40 may be used to generate a response to the alarm condition, or may create a log recording the alarm condition to alert a user that detection device 10 had been tampered with. Alarm controller 40 may comprise a clock and a location sensor. An alarm condition may result in the activation of, for example and without limitation:
a visual device such as a flashing light or LED;
an audio device such as a siren or other alarm noise-generator;
a paging device that may page an operator to notify the operator of the alarm event; or
a logging device, which may comprise for example an electronic memory which records that an alarm condition has occurred, and optionally the time and/or location at which an alarm condition occurs.
A series resistor 42 may optionally be added to the circuit comprising conducting wires 38. The presence of series resistor 42 makes it difficult, if not impossible, to bypass switch 32 by shorting or disconnecting conducting wires 38 without knowledge of the resistor value. Series resistor 42 may have a variable resistance, to make it even more difficult to bypass switch 32. Resistor 42 may be embedded inside switch assembly 30, so that it is physically inaccessible to a would-be tamperer.
Bolt 12 may be attached to a portion of a closure to be monitored by attachment means. Attachment means may comprise, for example, a metal wire 44 and a metal tab 46 for retaining bolt 12 to the closure to be monitored. Fixation of bolt 12 and mounting bracket 20 to the closure may be required in embodiments where the closure lacks locking means, in order to ensure that the closure being monitored cannot be opened without removing bolt 12 from entry hole 16, thereby resulting in the opening of switch 32.
In some embodiments of the invention, bolt 12 may be covered with paint. Attachment means may also be covered with paint in some embodiments. In one embodiment, the paint is hard and thick to prevent wear through normal use. In another embodiment, the paint loosely bonds to bolt 12, such that the paint is easily removed and must be reapplied periodically. The presence of paint on bolt 12 prevents a would-be thief from cutting bolt 12 and later repairing the cut to make bolt 12 appear undamaged. Bolt 12 may, for example, be painted in a highly visible color to indicate the area to be inspected when the item arrives at a destination point. Such visible coloring possesses a further advantage in that efforts to tamper with bolt 12 will damage the paint, thereby providing the person checking device 10 with an immediate visual indication that bolt 12 has been tampered with.
When hatch 50 is in the locked position, bolt 12 is inserted through locking ring 58 and threadably received in entry hole 16 of mounting bracket 20, such that end 14 depresses button 34 of switch 32. Locking ring 58 maintains latch 56 in the locked position. Hatch 50 cannot be opened without releasing latch 56 from the locked position. Latch 56 cannot be released without removing bolt 12 from locking ring 58. Therefore, hatch 50 is secured in such a manner that it cannot be opened without removing bolt 12 from entry hole 16, thereby resulting in the opening of momentary switch 32 and the creation of an alarm condition as described above. In this configuration, securing means such as wire 44 and tab 46 are optional, and mounting bracket 20 need not be attached to frame 54, since tamper and intrusion detection device 10 must be opened and bolt 12 removed from locking ring before access to hatch 50 is possible, regardless of whether or not device 10 is affixed to hatch 50.
When man-hole cover 70 is closed, bolt 12 may be threadably received in mounting bracket 20 to depress momentary switch 32 in switch assembly 30, as described above. In this embodiment, the positioning of tamper and intrusion detection device 10 is such that removal of handle 72 to open man-hole cover 70 can only be accomplished by detaching bolt 12 from entry hole 16. Removal of bolt 12 from mounting bracket 20 allows momentary switch 32 to return to the open position, thereby resulting in the creation of an alarm event as described above.
To monitor tampering with sensor 80, bolt 12 is passed through an opening 84 through sensor 80, and is threadably received in entry hole 16 of mounting bracket 20. Because of the positioning of bolt 12 and switch assembly 30, sensor 80 cannot be removed to access the contents of the tank without removal of bolt 12 from entry hole 16 of mounting bracket 20. Removal of bolt 12 from mounting bracket 20 allows momentary switch 32 to return to the open position, thereby resulting in the creation of an alarm event as described above.
While a number of exemplary aspects and embodiments have been discussed above, those of skill in the art will recognize certain modifications, permutations, additions and sub-combinations thereof. For example, the switch 32 could comprise a potentiometer adapted to have a resistance which varies in response to insertion of bolt 12 into opening 34, and wires 38 could be connected to an analog voltage detector adapted to produce a signal indicative of the extent to which bolt 12 is within opening 34.
It is therefore intended that the following appended claims and claims hereafter introduced are interpreted to include all such modifications, permutations, additions and sub-combinations as are within their true spirit and scope.
