Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
2000-02-10
2002-06-25
Lee, Benjamin C. (Department: 2632)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S686600, C340S545300, C340S568800, C340S568100, C340S600000, C250S221000
Reexamination Certificate
active
06411215
ABSTRACT:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable
REFERENCE TO A MICROFICHE APPENDIX
Not Applicable
BACKGROUND OF THE INVENTION
This invention relates to methods for detecting the position or state of an object, and more particularly, using optical means to confirm that a specific object is in a specific desired location, orientation, or state.
It is often required to confirm, from some distance, for example, that a mechanical or other device is in a specific position or configuration, or that an electrical device is powered on or off, that a residential sliding or hinged door is closed and also locked, or that a stove element is not left on for an extended time after use. Prior art has proposed a variety of solutions.
For example, U.S. Pat. Nos. 3,643,249 to Haywood, 4,453,390 to Moritz et al., 4,559,796 to De Forrest, Sr., 4,683,741 to Fields, 4,760,380 to Quenneville et al., 4,912,456 to Mickel, 5,062,670 to Grossman, and 5,111,007 to Miller et al. each disclose an apparatus or system to monitor and indicate whether a door lock set is in the locked position. However, these all require that a specially designed door lock set or mechanism be used, or that special modifications be made to the lock set mechanism or door. Also, as the monitoring method is electrical in nature and is mounted in the door, remote monitoring from the moving or swinging door is difficult as cabling to a moving device always presents several problems (such as how to route the cable, and fatigue of the flexing cable). And local monitoring (that is, a stand-alone unit with no external cabling) requires battery operation, which presents other problems (such as the requirement to change the battery periodically, and the difficulty or expense of remotely monitoring the door locked status, for example by using radio frequency transmission). U.S. Pat. Nos. 4,394,584 to Spahui et al. and 4,507,654 to Stolarczyk et al. can show that a door or window is closed but not whether it is locked. Also, they require the installation of cabling to the door or frame, or a battery-operated device to be located at the door or window, and again, this creates a maintenance and remote monitoring problem. U.S. Pat. Nos. 3,710,052 to Jette, 4,717,909 to Davis, 5,257,841 to Geringer et al., and 5,825,288 to Wojdan, are special assemblies that must be mounted in a door frame to monitor the position of the lock bolt, and as such require a difficult installation procedure of the assembly into the door frame, as well as of cabling to the assembly in the door frame. Also, the assemblies must be compatible with the type of lock and bolt installed, and also require careful mechanical alignment. Finally, these are electromechanical devices, and as such have electrical contacts that can wear out or corrode, have moving mechanical parts that can break or require realignment, and as these devices are accessible from the door frame's mortise, they are vulnerable to damage and vandalism.
And in any case, the above solutions are all specific to doors and windows, and not to the myriad of other monitoring applications, such as stove control dials and sliding doors.
There are many systems described in the prior art for detecting changes in volumes of space. For example, U.S. Pat. Nos. 3,886,549 to Cheal et al., 4,027,303 to Neuwirth et al., and 4,319,332 to Mehnert are intended as security systems to detect new or missing items on a surface, or in a region space. However, these are not well suited to detecting the following; changes in position or orientation of a smaller specific object in that space—especially in the presence of larger objects, or small changes in position of those larger objects in the monitored region, or very slow changes. Also, these are complex systems with microwave radio frequency operation, significant processing requirements to characterize, store, and compare the state of successive scans of the region, and/or other characteristics which result in high construction costs.
Other prior art discloses methods to count or detect objects passing through an area, for example to count items on a conveyor belt or stop a machine if an obstruction is detected in a particular zone. Examples include U.S. Pat. Nos. 3,889,118 to Walker, 4,590,410 to Jonsson, 4,659,922 to Duncan, 5,250,801 to Grozinger et al., 5,416,316 to Kappeler, 5,812,058 to Sugimoto et al., and 5,852,292 to Blümcke et al. However, these have one or more of the following shortcomings; not directional to a specific location, cannot detect the movement or rotation of a specific part of a larger object, or are too limited in the distance to the sensed object.
U.S. Pat. No. 5,475,367 to Prevost discloses a system for detecting the continued presence of valuable items. However, this requires a detector unit to be mounted close to the monitored object, and in any case, is not well suited to detecting small changes in position or rotation of a part of a larger object.
U.S. Pat. No. 5,854,520 to Buck et al. discloses a timer to control the duration that power is applied to the burners of a stove. However, this system requires either substantial modification to an existing stove's controls and electrical system, or that the stove be initially manufactured with the required relays and circuitry. Other inventions also require special wiring to a stove or oven, and mechanical switches to be retrofitted or incorporated into the stove controls and/or other assemblies. For example, U.S. Pat. No. 3,852,728 to Flagg, Jr. discloses an alarm that provides a continuous indication when a stove element is on, and an intermittent indication for a period afterwards, while the stove element cools. This has the problems that users would become so accustomed to the alarm that it would provide little alerting value, there is no provision for remote monitoring, and high-temperature wiring and switches must be installed in the stove. U.S. Pat. Nos. 4,334,145 to Norris, Sr., 4,446,455 to Nashawaty, and 4,577,181 to Lipscher et al. disclose an alarm which detects when a stove element is powered on but there is no utensil placed onto the corresponding stove element. This requires mechanical modifications to be made to the stove to accommodate a specially designed switch, a switch to be attached to each burner assembly, the switch and wiring to be suitable for high-temperature operation, and the switch and assembly to be kept clean so movement is not impeded. Additionally, it does not alarm if the stove element is left on with a utensil on the burner, and does not allow for remote monitoring of the switch status. U.S. Pat. No. 5,608,378 to McLean et al. discloses a system to alert a user if a stove element is turned on and then a dwelling exit door is opened—for example to leave the dwelling. This has the problems that electrical wiring is required to the stove control or indicator light and also to the exit door, that the alarm will sound if the door is opened for another purpose (for example when another member of the family arrives home for dinner), and that the system is of no value if the home-owners leave through an alternate door, or leave the stove on all night while they sleep.
And in any case, the above solutions are all specific to stoves, and not to the myriad of other monitoring applications.
U.S. Pat. No. 4,063,044 to Stephan discloses a system utilizing photocells to monitor the line-busy lights on a telephone. However, the photocells must be placed directly over the lights, the invention is described for use with multi-line telephones only, and alarming is described only when all lights are illuminated (rather than when any one is illuminated, which is more meaningful for security purposes).
Clearly, there is a need for a method of remotely sensing, for example, whether a door is locked, or whether a stove is turned off, without the limitations, installation difficulties and other undesirable features of the prior art.
BRIEF SUMMARY OF THE INVENTION
It is an object of the present invention to provide a method to detect that a specific obje
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