WO2011019406A2

WO2011019406A2 - Low-cost switch sensor remote deadbolt status indicator

Info

Publication number: WO2011019406A2
Application number: PCT/US2010/002248
Authority: WO
Inventors: Joseph Eichenstein; John V. Mizzi
Original assignee: Joseph Eichenstein; Mizzi John V
Priority date: 2009-08-14
Filing date: 2010-08-13
Publication date: 2011-02-17
Also published as: WO2011019406A3; WO2011019406A9

Abstract

Low cost remote reminders provide information to indicate whether or not a deadbolt lock of a building door is locked. A sensor switch detects transition of a state of a household door lock from unlocked to locked. The sensor switch effects electronics which are used as a basis for a reminder system.

Description

LOW-COST SWITCH SENSOR

REMOTE DEADBOLT STATUS INDICATOR

FIELD OF THE INVENTION

The present invention relates to low cost remote reminders which indicate whether a deadbolt lock of a building door is locked or unlocked.

The present invention relates to a deadbolt lock reminder preferably using a passive receiver, which receives a signal enabling a user to ascertain at a later time whether a deadbolt lock was not locked in the recent temporal past.

BACKGROUND OF THE INVENTION

People often leave their house and wonder whether they locked the deadbolt of their front door. Typically they would have to get out of their car and return to the house and check to see if the door is bolted. While remote status checking devices using radio communications links are known, a simple low cost device is needed.

US Patent application 2004/0080403 of Eshel relates to a lock status indicator. It comprises a remote indicator in the form of a key fob that has a visual or audio indication of the status of a vehicle lock. A time indicating device may also display the time of the last lock status change. No information on the communication sequence or operation of the indicator is provided by the inventor.

US Patent 6,703,919 of Baset describes a method of confirming remote keyless entry lock status using a key fob with a counter that is incremented when the lock button is pressed and reset to zero when the unlock button is activated.

US Patent 6,166,634 of Dean is a garage door status signaling device using a transmitter attached to a switch at the garage door. This transmitter is activated when the garage door is opened thereby sending a signal to a remote receiver (always on) with an interval timer to activate an alarm.

US Patent 7,196,623 of Wang is a remote reminding system to warn a user of an undesirable condition of an appliance or garage door. This is a long-range radio communications system whereby the remote unit sends signals to poll the base unit continuously. The remote unit has a computer for decrypting the encoded data and making decisions based on received information as to inform the user of certain undesirable conditions of specific appliances.

US Patent 7,498,936 of Maeng for a wireless event status system can be used to ascertain the status of a building door lock remotely. An informer transmitter at the door operates to transmit a status signal whenever the door lock status is changed. A receiver in a remote key fob receives the signal since it is always in the active receive state. A visual indicator in the form of a status light on the key fob is turned on or off by the received signal to indicate if the door is locked or unlocked. This last status is stored in the key fob for interrogation when the key fob is out of range of the informer transmitter.

US Patent 4,490,999 of Castle describes a non-electronic, mechanical door lock indicator with a rotary indicator viewable through a transparent window. The indicator is synchronized with the movement of the door bolt to indicate whether the door is locked or unlocked.

However, the prior art does not reveal a remote deadbolt status indicator which is low cost and uses a switch sensor easily installed by the customer.

At times, people leaving a house or apartment may simply forget to use their key to lock the deadbolt of their front door. At other times they may be distracted by a cell phone call or a toddler in tow. The door security would then be left to an easily penetrated snap latch lock.

Although several patents in the prior art relate to proximity detectors of people in a vicinity, none are used to trigger a simple alarm at the door if the deadbolt had not been locked.

US Patent number 5,659,291 to Kennedy, et al., is a key-in-ignition reminder system which controls automatic locking and unlocking of vehicle doors depending on conditions after it is determined that a key has been left in an ignition lock. An alarm warning the driver is also provided. The key, with a built-in transponder, communicates a key code via local radio transmission. Although a proximity switch is mentioned in the patent, (see column 2 lines 50-51), the proximity switch is a "door proximity switch" that is used to determine if vehicle door is open or closed. This door proximity switch is understood to comprise a set of switch contacts or a magnet and sensor arrangement, but is not a capacitive proximity detector. That is, Kennedy '291 does not suggest deadbolt or person detection for a home or business structure.

US Patent number 5,608,378 to McLean, et al., discloses either a wired or wireless electric stove warning system to remind a person leaving through a door that the stove is "on". The detection of a person leaving is either by a weight actuated door mat switch or by a door switch in the door jamb. (See McLean's column 3 line 65 through column 4 line 15). Mclean makes no disclosure or suggestion of a deadbolt or proximity detector, although an alarm (visual and/or sound) at the door is described.

US Patent number 5,565,843 to Meyvis is an unrelated garage door message display. It warns of a garage door being unlocked and other conditions.^

US Patent number 6,032,500 to Collard, Jr., et al., discloses a kit for retrofitting a door with a security lock system. The block diagram of Figure 5 shows block 130 described as a deadbolt position sensor. The deadbolt sensor is shown communicating with a remote door lock control logic and relays/drivers (block 150), described in column 4, lines 64-65, although reference numbers are incorrect. Collard's column 6, lines 11-12, discloses a "proximity switch" that is called out as a substitute type to sense lock position. Such a lock position sensor, however, would not be possible using a proximity detector designed to sense the presence of a person.

US Patent number 6,705,940 to Moore describes a portable doorway bug deflector. Except for being a fan operated unit mounted on the side of a doorway and controlled by a door switch, this patent is completely unrelated to the invention. There is no notion of deadbolt, reminder warning, or proximity detector.

US Patent number 6,166,634 to Dean describes a garage door status signaling device that uses a transmitter to send a signal to a remote audio visual display, and includes a receiver and a timer which again restarts the audio if the door is still open (column 1, lines 45-46; column 2, lines 41-47. There is no disclosure or suggestion of proximity detectors or deadbolts.

US Patent number 6,731,200 to Wagner, et al., is a system for indicating the status of a hotel room for such things as "do not disturb" or "maid service". While the Wagner system may be battery powered, it is preferably wired into the "hotel's electrical system;" column 4, lines 35-38. Functions are microprocessor controlled and an alarm switch input can come from a "newly installed door proximity switch or from a motion sensor;" column 5, lines 36-37. Other references to motion sensors and infrared motion or heat sensors are found in column 6, but reflect the use of displays and people sensors at the door, which not only complicate intended operation, but significantly increase cost. No disclosure or notion of deadbolt position sensing is found in Wagner.

US Patent number 6,857,671 to Fly discloses an electromagnetic locking device for a door. Although a "proximity switch" is mentioned in the patent, Fly's proximity switch is designed to sense the displacement of the electromagnet housing to detect tampering. There is no disclosure, suggestion or notion of audio/visual reminder, people sensing, or deadbolts.

US Patent number 7,037,034 to Dillingham discloses a hydraulic safety door system for a hopper body, but is not related in any way . It is unrelated to doors using deadbolts. Dillingham at column 5, lines 17-24, describes a proximity switch using switch contacts, which does not comprise a capacitive proximity sensor for detecting a person.

US Patent number 7,205,777 to Shultz, et al., discloses an improved capacitive proximity switch, which is described in relation to applications to a motor vehicle door handle. The detector itself is said to display improved reliability, especially in rain conditions.

US Patent number 7,234,201 to Brown, et al., discloses a door closer power adjusting device that uses an electric motor to adjust the closing and opening force of a closer that is similar to a manual spring operated automatic door closer (often used on conventional screen doors). Brown's operating switch is described in the form of a "motion detector" or an "infra red proximity switch" (column 2, lines 6-12), but does not disclose or suggest the use of a deadbolt or reminder.

US Patent number 7,372,355 of Agronin, et al., discloses a remote controlled wall switch actuator. Figures 5A-5D present a block diagram with block 176 labeled as a motion or proximity sensor, which can be used to operate the wall switch remotely by wireless signal (column 8, line 34). While there is mention of the word "lock" within this patent, it is within the context of "lock-out" (column 9, lines 37-38), but Agronin does not disclose or suggest a door, deadbolt lock, or reminder alarm.

US Patent number 7,378,980 to McFarland discloses triangulation of position for automated building control components. McFarland's Figure 1 shows a block diagram of a building automation device, wherein block 12 is a sensor/actuator. In column 1, lines 42- 43, McFarland discloses that the sensor "also may be a limit or proximity switch." Otherwise, however, the subject matter of McFarland is quite divorced from door locks or reminders.

US Patent number 7,448,246 to Briese, et al., discloses a machine for window frame corner fabrication, including mechanical switches which detect position of moving machine elements, but does not teach or suggest doors, deadbolt locks and/or reminder alarms.

US Patent number 7,450,012 to Harmon discloses an unrelated RFID reader/writer device.

US Patent number 7,380,375 to MaIy discloses an alarm system for a loading dock. The MaIy alarm system uses a "remote body sensor," which can be a "motion detector", "infrared sensor" or "ultrasonic proximity sensor" (Figure 6, item 70; column 4, lines 49- 56). In effect, Maly's alarm system operates similarly as does a typical motion sensor driveway light fixture.

US Patent number 7,466,040 to Bruwer discloses a touch sensor controlled switch with intelligent user interface. The switch with intelligent interface comprises a group of "microchip" (see Figure 2) applications and uses a combination of touch or proximity switches with ordinary slide or pushbutton switches to do a wide variety of things, e.g.,

"find in the dark", act as an intelligent flashlight, or even toys (which can already be found on store shelves). Bruwer's column 6, lines 2-11, describes toys and child activation through proximity action. Column 6, lines 31-34, describes reference values in capacitive sensing such as would be used in this and any other capacitive proximity detector application.

Residents often leave their home, e.g., house, apartment, garage, store, etc., and at some point in time thereafter wonder whether they locked the deadbolt of their front door. Where they think of it while on the premises, e.g., in the car on the driveway, they have to get out of the car and return to the house or apartment to check or verify that the door is bolted. When the thought occurs to them that they may not have locked the deadbolt at some distance to their home or apartment, and they cannot readily return home to verify, their concern and anxiety level will typically increase.

Some such residents may be lucky enough to have a neighbor, friend or relative they can call to travel to the house or apartment and determine whether the deadbolt is locked in place, but most residents are not so fortunate. For that matter, a person without a key to the deadbolt may be unable to accurately determine its locked/unlocked status.

In order to address the problem, and provide residents that tend to forget whether they have actually locked their deadbolt, various remote status checking devices have developed. That is, various remote status checking devices are known to use radio communications links.

For example, US Patent 7,498,936 to Maeng describes a wireless event status system that can be used to ascertain the status of a building door lock remotely. In Maeng, an informer transmitter at the door operates to transmit a status signal whenever the door lock status is changed. A receiver in a remote key fob receives the signal since it is always in the active receive state. A visual indicator in the form of a status light on the key fob is turned on or off in response to the received signal, i.e., to indicate whether the door is locked or unlocked. This last status is stored in the key fob for interrogation when the key fob is out of range of the informer transmitter.

Maeng's Fig. 4 illustrates a functional block diagram of a wireless enabled notification

system employing a remote status notification device having a processor with memory operable to store a current state according to one aspect of the invention. Informer 420 includes a processor 402, and a radio transmitter 403 operable to send and receive wireless signals such as RF signals using antenna 404 and wireless communication medium 410. Notification system 400 includes a remote status notification device 411 having a radio receiver 406 coupled to antenna 405 and operable to receive signals via communication medium 410. Remote status notification device 411 further includes a processor with memory 407, an input device 409 such as an acknowledge button, an output device 408 such as an indicator and/or speaker.

Processor 402 formats a status message including an identification that identifies informer 420 and a current status provided by status sensor 401. Upon status sensor 401 providing a status to processor 402 and processor formatting a status message, radio transceiver 403 transmits the encoded status message using wireless communication medium 410 such as an RF communication medium. Radio receiver 406 receives the signal and status message communicated by informer 420 and provides a decoded signal and status message to processor

407. Processor 407 checks the decoded signal to determine if the decoded signal includes a unique identification number for informer 420 and confirms the format of the data using a predefined data format.

Such operation is not only quite complicated, but requires substantial battery power to operate at both ends. For example, Informer 420 requires processor 402 to determine what type signal to send via radio transmitter 403. Moreover, remote status notification device 411 must operate with a processor with memory 407 to process the received signals and communicate the proper notification commends to input device. That is, processor 407 must check the decoded signal to determine if the decoded signal includes a unique identification number for informer 420 and confirms the format of the data using a predefined data format.

OBJECTS OF THE INVENTION

It is an object of the present invention to provide a low-cost switch sensor remote deadbolt status indicator.

It is also an object of the present invention to provide a switch sensor which starts a transmitter at a door lock location upon sensing the instant that a deadbolt is locked.

It is also an object of the present invention to provide a low cost remote door lock indicator with a self shut-off feature operating after a fixed duration of time length has elapsed.

It is yet another object of the present invention to provide a switch sensor of the transmitter, whereby the switch sensor is provided at a location in the vicinity of the strike plate having an opening through which the deadbolt locks the door, so that the transmitter can communicate with the user's remote, hand held key fob indicator.

It is another object of the present invention to provide a deadbolt lock reminder triggered by a proximity detector upon sensing the instant of a person leaving the immediate vicinity while the deadbolt is in an unlocked state.

It is yet another object of the invention to provide a deadbolt lock reminder which includes a normally closed deadbolt detector switch that supplies power to a proximity detector that detects a presence of a person in a vicinity of a door whenever the deadbolt is not locked.

It is still another object of the invention to provide a door lock alarm wherein a proximity detector switches into a "person no longer detected" mode, which thereby sounds an alarm to remind the person to return to lock the deadbolt.

It is still yet another object of the invention to provide a door lock alarm with a timer period which elapses while the person is still within earshot of the alarm.

It is therefore an object of the present invention to preferably provide a deadbolt lock reminder system comprising a passive receiver that stores a reminder signal or starts an incremental timer, which when accessed, enables a resident who may not recall whether they locked the deadbolt to ascertain at a later time whether the deadbolt was left unlocked in the recent temporal past.

The novel deadbolt lock reminder is intended to be used with any conventional deadbolt, or deadbolt system utilized to secure any type door, for example, inner doors, outer doors, garage doors, cabin doors, etc., with out limitation, used to restrict access in any home, house, apartment, garage, store, business, boat, warehouse, etc., without limitation,

It is also an object of the present invention to provide a deadbolt lock reminder that overcomes the shortcomings of the prior art.

SUMMARY OF THE INVENTION

In keeping with these objects and others which may become apparent, this invention is a low-cost system using a transmitter unit comprising a transmitter and a switch sensor to detect the presence of a deadbolt in a locked position, whereby the door to secured is assuredly locked/secured. The switch sensor is dual purpose. It is used to start the transmitter operation as well as to sense the bolt position in a very direct manner. The transmitter is low voltage or battery operated, such as, for example, using ordinary alkaline batteries (such as 2 or 3 AA cells). This type of power for powering the transmitter unit avoids the first cost of an AC line-powered power supply or charging stand; an ugly extension cord is also avoided in this manner. Please note, however, that an alternative embodiment includes AC/DC converter connected to power the switch sensor, transmitter and any logical circuitry for application where changing a battery would be inconvenient. A very small hand-held indicator, such as a key fob powered by a button cell, contains a receiver to communicate with the transmitter at the door.

A major feature of this invention is the ease of installation of the transmitter unit at the door with the switch sensor by a customer with average skills and minimal tools. In fact, the only tool necessary is a drill capable of drilling a single hole adjacent the deadbolt. Beyond low first cost, low cost operation in terms of long battery life is also a feature of this invention.

Since only short range communications between the transmitter and receiver in the hand-held indicator is required for this invention, advantage is taken of radio frequency bands reserved for such low power communications. In the United States, the FCC permits "unlicensed operation" (under CFR 47 part 15 regulations) of such devices in the 900MHz, the 2.4GHz, and the 5.8 GHz bands. Other jurisdictions have reserved bands for similar operation. Any of these bands can be used.

The low-cost features inherent to the design of this invention first relate to the communications concept and operation. At the door that is secured, the transmitter unit comprises only a simple transmitter (not a transceiver) and sensor. At the key fob, only a simple receiver (not a transceiver) is required for receiving signals transmitted from the transmitter unit. This is different than complex prior art transceivers which need transmissions in both directions or have a receiver that is always "on", and which may be capable of performing tasks other than visual indicator status, such as locking an unlocked door from a remote position. Those features are not within the scope of the present invention.

In one embodiment, the operation which supports the use of such a spartan system is as follows:

The switch sensor is located at the door being monitored and configured to detect an open position and a closed position of a deadbolt by which the door is secured. Upon detection of the deadbolt in the locked position, the sensor immediately starts the transmitter sending a signal in the frequency range at which the receiver in the key fob is tuned for a predetermined short time period (preferably set to be 5 minutes or less); at the end of the period, the transmitter subsystem shuts itself off regardless of the switch sensor still being activated. This self-shutoff is similar to the automatic shutoff of a digital camera after a period of non use.

If a key fob inquiry button is pressed during this transmission period and the key fob is within the range of the transmitter, the receiver within the key fob receive state is activated, the transmitted signal from the transmitter located at the door is received and a signal is generated that activates a visual or other sensory perceptible indicator, such as a green LED indicator, indicating that the deadbolt is in its locked position. Other visual or vibratory indicators may be used.

However, if the key fob inquiry button is activated shortly after the user has exited the door with the transmitter unit, and the transmitter is not transmitting the signal representative of detection of the deadbolt in its locked position but still within an operational range, the logical circuitry in the key fob decides that the deadbolt is not in its locked position. A signal is then generated to activate a visual or other sensory perceptible indicator, such as a (preferably) blinking red LED, which will glow indicating that the person has forgotten to operate the deadbolt. Any operation of the key fob out of range or after the normal transmission period will give the same blinking red LED indication even if the deadbolt is in the locked position.

Other features that are related to low cost include the switch sensor assembly. This preferably includes a few easily assembled components, such as molded plastic parts affording easy custom adjustment for most installations with a low cost switch, such as, for example, a momentary single pole, single throw SPST switch which can be a membrane switch of the type used on a telephone or calculator. Other types of switch sensors, such as magnetic, optical, ultrasonic or motion sensors and the like, can be used, as are known to those skilled in the art.

To greatly extend the life of the transmitter subassembly battery, the signal transmission is preferably pulse modulated with full power pulses of a reduced nature, such as, for example, only a 5% duty cycle or less, for example, pulses of radio frequency of 5ms duration every 100 ms period. In this manner, full range is not sacrificed since the pulses are full power, but the battery life is extended over ten-fold compared to continuous full power transmission over the five minute transmission periods. The service life of the key fob receiver battery is very long since the receiver and indicator LED's are only operated while the inquiry button is pressed. Besides, a receiver function is a low power device compared to the transmitter function of a normal remote keyless entry automotive fob. The key fob unit is configured for easy replacement of the battery cell therein.

In an alternate embodiment, the switch sensor is provided as an integral part bonded to the conventional manufactured metal strike plate deadbolt frame that is typically attached to the door jamb. The switch sensor may be attached to the metal strike plate by two fingers extending rearward from the strike plate, or by any other mounting means which mounts the sensor to the strike plate in the vicinity of where the deadbolt moves to during the locking operation. The important feature is that the deadbolt, upon locking, is introduced through the cowling of the access hole of the strike plate in a locked position, where it activates the switch sensor concealed within an access hole for the deadbolt. The switch sensor generates a signal to activate the transmitter assembly communicating with the user's key fob, i.e., the receiver thereat. The switch sensor is preferably therefore concealed within the access hole for the deadbolt. It is a very low profile, dome operated switch, requiring only a small hole through to the interior for a small gage two-conductor cable to the transmitter assembly. This alternate embodiment simplifies the installation of the security system. Costs are minimal in view of the fact that the door jamb strike plate may be manufactured with the switch sensor by a deadbolt lock manufacturer.

Building doors are typically locked with a key engaging deadbolt lock, which has a movable deadbolt for locking the door. Upon activation by the key, the deadbolt moves from a retracted unlocked position inside the deadbolt lock housing located within the door, to an extended locking position when the deadbolt penetrates a recess in the door jamb surrounding the door, thereby preventing the door from opening.

To that end, in another embodiment, the present invention provides a deadbolt lock reminder that uses a normally closed switch to detect the position of a deadbolt in a locked state, which would be opened by it since the switch is strategically placed in the deadbolt recess. If the switch is in its normally closed state, the switch enables power from a battery source, e.g., two or more alkaline AA cells, to operate a proximity detector to detect a person in its vicinity. Preferably, a capacitive type proximity detector is used in view of its low cost and low battery drain, e.g., known proximity detectors used to trigger visual and audio displays in novelty items such as Halloween and Christmas decorations that are initialized automatically when a person is detected in the vicinity of the decoration. Other types of proximity detectors such as ultrasonic or infrared types may also be used. With added complexity, a microprocessor can be programmed to detect proximity using a related type of motion detector, but this is not necessary for the present invention.

In operation, when a person leaves through a door, the deadbolt is necessarily unlocked so the proximity detector is operating and would immediately detect the presence of a person. If the person locks the deadbolt, the switch is thereby opened which deactivates the proximity detector and associated circuitry. So as the person leaves, no alarm is sounded. However, if the person leaves the area without locking the deadbolt, the absence of the person triggers a single shot timer with a delay of approximately a second or less. At the end of that time period, an alarm sounds (for a timed period) alerting the person to his or her negligence (i.e., negligence in failing to secure the lock) while he or she is still within earshot of the alarm.

If the person returns within the timer period, the proximity detector detects their presence and switches state, which blocks the alarm and possibly re-triggers when the person "leaves" for a second (or "third") time without locking the door. This single shot timer scheme eliminates many nuisance alarms resulting from brief non-detection periods that can be triggered by bending down to pick something up, for example.

The deadbolt lock reminder "reminds of failure to deadbolt" with least annoyance when used at doors that are intended during normal operation to be in the state of being locked by a deadbolt most of the time. The deadbolt lock reminder is enabled whenever the deadbolt is opened, e.g., either by an indoor latch or by a key from outdoors. However, if the deadbolt is locked either from the inside or outside before the person leaves the vicinity, no alarm is triggered.

The invention is readily distinguishable from known prior art (e.g., Bruwer) because unlike the present invention of Applicant herein, the aforementioned prior art of Bruwer '040 uses a proximity detector typically as a "touch switch" with the sensor connector connected to a touched item. Note that in this alternate embodiment of the present invention, the deadbolt is not connected to the sensor of the proximity detector, nor does the deadbolt behave as a "touch switch". That is, the proximity sensor is included in the inventive deadbolt lock reminder simply to detect the presence of a person in the vicinity of the door to be deadbolted.

The deadbolt lock reminder, unlike Bruwer, does not propose doing dynamic

"touch/no-touch" level adjustments via a special chip, nor does it have a heavy load such as a motor or flashlight. That is, the deadbolt lock reminder need only drive an audio alarm such as, for example, a piezoelectric annunciator that is activated for a timed period at the detection of a non-presence of a person. Also in Bruwer, a timer may be activated when a no-touch condition is sensed by the proximity/touch sensor causing the load to be deactivated. In contrast, in the present invention, the alarm is activated by the "no-person condition."

The purpose of a further alternate embodiment of this invention is also to provide a deadbolt lock reminder system whereby a concerned person at a remote location is enabled to inquire as to the time and date of the last time a deadbolt lock in place at a door in the person's home or business was locked. This inventive deadbolt lock reminder system is able to help the concerned person remember to lock the deadbolt. If the inquiry is made close enough to the door to be locked with the deadbolt lock, and if the deadbolt lock reminder system has determined that the deadbolt lock is in an unlocked state, the concerned person can return to the store or home and lock the deadbolt.

The deadbolt lock reminder system of this alternate embodiment is implemented in two cooperating subsystems. The first subsystem comprises a hand held receiver subsystem, such as, for example, a receiver subsystem constructed into a hand held housing, such as a key fob or like communication signal receiving device. Where the receiver subsystem comprises a key fob, the key fob is typically attached to the lock key as per a key chain. The hand held receiver subsystem is preferably a passive receiver which is receptive to a received signal, such as an RF signal. The RF reminder signal enables the passive receiver to receive date and time information for storage in non-volatile memory from a transmitter in close proximity (the other subsystem) which is energized when the deadbolt enters the recess in the door jamb thereby locking the door. The locking action is sensed by a normally open sensor switch which physically engages the deadbolt. The information thus stored on the key fob may be displayed on the surface of the key fob by pressing a momentary switch button thereby powering a display via a small button battery or cell within.

In more details, the received information comprising the received reminder signal may be displayed in a display device associated with the surface of the hand held receiver. In one embodiment, the data may be displayed automatically upon receipt, avoiding any need for a memory in the receiver subsystem. Alternatively, the data is stored in memory and retrieved for display by a manual data input, such as by pressing a momentary switch button by the system user. The display is powered by a power source, such as a small button battery or cell within. The technology to implement this system has been proven through the wide use of passive identification devices, such as, for example, RFID tags and RFID readers in the consumer product industry.

Therefore, in this further alternate embodiment, the action of locking the deadbolt causes a short powerful transmission of the current day and time for storage on the key fob whereby this information is portable and accessible at any time or place. The key fob will display the last time and day of locking the deadbolt. The reader should note that while the receiver subsystem is described as communicating the last locked/unlock status using a visual display device; the invention is not limited thereto. That is, the receiver subsystem may comprise any known device or means for communicating a locked or unlocked condition. For example, the status may be communicated to a system user in possession of the hand held receiver subsystem using apparatus providing a visual, tactile or auditory signal. But in the case of a display device, the hand held receiver subsystem displays the last time and day of locking the deadbolt. For example, and in a case where the last time the deadbolt lock was locked is not "today", the deadbolt can be presumed to be unlocked (unless someone else locked it). The previous time and day is automatically overlaid by the current data with every transmitter subsystem operation.

The second subsystem of the deadbolt lock reminder system of this embodiment comprises a transmitter subsystem located at the door proximate the deadbolt lock. The transmitter subsystem is energized to generate and send the reminder signal when it detects that the deadbolt enters the recess associated with the door lock, thereby locking the door. For example, the deadbolt may be installed and positioned in a door jamb of a residential or business door. That is, the locking action is detected by a sensor comprising the transmitter subsystem, such as a normally open sensor switch that physically engages the deadbolt. The sensor responds by activating the transmitter comprising the transmitter subsystem to transmit a short powerful transmission modulated with data comprising the current day and time.

In an alternate embodiment, the transmitter subsystem is simplified so that it just emits a simple data output, such as a single RF burst upon detecting that the deadbolt is locked, and then shuts down. This single RF burst is received by and used by the hand held receiver subsystem, such as a key fob, which includes the passive receiver. The passive receiver is "awakened" by receipt of this single RF burst and resets a free-running elapsed time counter with integral display which is also housed in the hand held receiver, such as a key fob. In this way, locking of the deadbolt lock resets the display which starts displaying elapsed time (hours and minutes) from that point on. The display and counter are always on and these can be a standard stop watch module with integral display. In an alternate embodiment, the time counter provides an elapsed time (such as, for example, in hours and/or minutes) from that point on, which is displayed or otherwise communicated to the concerned user. In this embodiment, the display and counter are always on. In one embodiment, the free-running elapsed time counter comprises a standard stop watch module with integral display.

The receiver subsystem is constructed in this alternate embodiment so that it does not include a real- time clock or time/date storage means in this embodiment. So in the case where the display of the elapsed time counter overflows, visually displayed digits go blank but the dots demarking hours and minutes will keep operating repetitively. For example, the hand held receiver subsystem can emit a vibratory signal, an auditory signal or a visual signal, for example, by blinking at a predetermined rate, such as, for example, one per second rate. The user can easily determine if he or she had forgotten to lock the deadbolt by viewing, feeling or hearing the display. If the elapsed time shown (or overflow condition) is greater than the time since he or she had left the door site, the status of the deadbolt is "NOT LOCKED" (unless someone else locked it after departure). The user need not be aware of the date.

The transmitter is configured for transmitting a dead lock reminder signal identifying that a state of the deadbolt has changed to one of locked or unlocked upon detection of same by the detector. The hand held receiver subsystem is configured in a hand held housing to receive the dead lock reminder signal at a time of transmission, and maintain a status of a last change to a locked or an unlocked state for communication to a user of the hand held receiver subsystem. The detector of the transmitter subsystem comprises a sensor switch which is arranged to engage the deadbolt to generate and direct a detection signal to the transmitter that activates transmission of the dead lock reminder signal at a change of state of the deadbolt. Preferably, the transmitter subsystem sensor includes a real time clock that supplies a time and date for embedding into the dead lock reminder signal, and wherein the transmitter modulates the dead lock reminder signal to include the time and date. The transmitter within the transmitter subsystem generates a single, short RF burst comprising the dead lock reminder signal modulated to include at least the change of state of the deadbolt, and then shuts down. In an alternate embodiment, the transmitter in the transmitter subsystem can be a transmitter as known to those skilled in the art, such as for example, a Bluetooth transmitter, a Wi-Fi transmitter that transmits according to IEEE 802.11 or a transmitter subsystem comprising a power control module.

In yet another alternate embodiment, to prevent rare occasions where unintentional resetting of the free-running elapsed time counter may happen, a code matching scheme may be used with an enhanced transmission burst. In this embodiment, the reminder system is sold such that the transmitter and the passive receivers in one or more key fobs are matched whereby a unique common factory-set code is used by both entities. The transmitter burst that awakens and powers the passive receiver also sends this code which is received and compared to the code imbedded in the receiver electronics. Only if there is a code match will the receiver reset the free-running elapsed time counter. The problem being avoided is that of the key fob being in the vicinity of a source of a stray radio frequency emission of similar band of frequencies used by the reminder system.

In yet another embodiment, the reminder system operating according to any of the three above embodiments of this invention is incorporated into a deadbolt lock and sold as part of the total lock installation kit. A single module incorporating the transmitter subsystem with a prewired (dangling) sensor switch is installed as part of the lock and interacts with a modified deadbolt latch portion to which the sensor switch is then attached within the lock cylinder hole in the door. No extra holes are required to attach the sensor switch or to convey wires to it. No alignment of sensor switch to deadbolt is required as this is factory provided by virtue of the modified deadbolt latch subassembly. This also obviates any geometric cautions that may otherwise cause confusion relating to placement of the transmitter module on the outside or the inside of the door and to the door being hinged on the right or left side (as seen from the inside). The extra steps needed for installation of the lock with the reminder system are simple and minor as compared to the installation of an ordinary deadbolt lock.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention can best be understood in connection with the accompanying drawings. It is noted that the invention is not limited to the precise embodiments shown in drawings, in which:

Figure 1 is a front elevation detail of a first embodiment where the interior side of the door is configured with a locking system of the invention, and including a wall adjacent the door upon which a transmitter unit with switch sensor and transmitter is shown mounted relative to a deadbolt lock.

Figure 2 is a perspective view of the receiver key fob of this invention.

Figure 3 is an enlarged front detail of the interior side of the door configured with a locking system of the invention that highlights a deadbolt bridging the gap between the door edge and door jamb relative to the position of the switch sensor assembly.

Figure 4 is a side crossectional view of the deadbolt and switch sensor assembly. Figure 5 is a side exploded view of the various parts of the switch sensor assembly. Figure 6 is a block diagram of the transmitter subassembly and the receiver key fob.

Figure 7 is a perspective view of a deadbolt strike plate with integral switch sensor constructed in accordance with the invention.

Figure 8 is a side view of the strike plate of Figure 7.

Figure 9 is a back view of the strike plate of Figure 7.

Figure 10 is a front elevation detail of a portion of the door from the outside showing the outdoor mounting of an alternate embodiment of the reminder system of this invention.

Figure 11 is front elevation detail of a portion of the door from the outside showing the mounting of an outdoor capacitive plate and sound emitter when the reminder system is located inside.

Figure 12 is a block diagram of the reminder system of this invention.

Figure 13 is a perspective view of the exterior of a door with a deadbolt and the transmitter of a further alternate embodiment of this reminder system.

Figure 14 is an end view detail of the door showing the relative location of the transmitter and the key fob of this further alternate embodiment of this invention.

Figure 15 is a high level block diagram of both the transmitter and the key fob subsystems comprising the further alternate embodiment of this invention.

Figure 16 is a front elevation of a door and wall detail of an alternate embodiment of this invention using an elapsed time counter.

Figure 17 is a high level block diagram of both the transmitter and the key fob subsystems of the alternate embodiment shown in Figure 16.

Figure 18 is a flow chart of the operation of yet another further alternate embodiment of a reminder system of this invention incorporating transmission of a code burst.

Figure 19 is a perspective illustration of the unmodified (prior art) components used in the reminder system lock embodiment of Figure 18.

Figure 20 is a perspective view of the deadbolt latch subassembly showing the factory modifications required for compatibility with the reminder system of this further alternate embodiment.

Figure 21 is a perspective view of the sensor switch trigger rod unit thereof.

Figure 22 is a front elevation of the transmitter subassembly thereof.

Figure 23 is a crossection side view of the transmitter subassembly metal mounting ring thereof.

Figure 24 is a side elevation of the deadbolt latch subassembly within the lock cylinder mounting hole in a door with sensor switch and trigger rod unit attached of this further alternate embodiment.

Figure 25 is an edge view of a door lock area with the reminder transmitter subassembly thereof mounted on the inside of the door.

Figure 26 is an edge view of the door showing an exterior mounting of the reminder transmitter subsystem of this further alternate embodiment.

Figure 27 is a flowchart of the unique steps of installing a lock incorporating a reminder system of this further alternate embodiment shown in Figures 19-26.

DETAILED DESCRIPTION OF THE INVENTION

The following is a detailed description of example embodiments of the invention depicted in the accompanying drawings. The example embodiments are in such detail as to clearly communicate the invention. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present invention, as defined by the appended Claims. The descriptions below are designed to make such embodiments obvious to a person of ordinary skill in the art.

A low-cost switch sensor remote deadbolt status indicator of the first embodiment of Figures 1-6 includes a switch sensor which starts a transmitter at a door lock location upon sensing of a deadbolt being in a locked position. The transmitter is provided with a self shut-off feature operating after a fixed duration of minutes length has elapsed. The indicator also includes a receiver in a hand held unit, such as a key fob capable of receiving signals from the transmitter after the user presses an inquiry key on its surface. The hand held receiver has two indicators for alternately displaying the lock's deadbolt status as being locked or unlocked. In an alternate embodiment, the switch sensor is provided as an integral part bonded to the conventional manufactured metal strike plate deadbolt frame that is typically attached to the door jamb.

Turning now to Figure 1, a physical location of transmitter subassembly 11 with switch sensor assembly 10 relative to a door 1 with deadbolt lock 3 is shown in Figure 1. Door knob 2 is shown in its normal location below lock 3. Door jamb molding 7 on wall 6 is the location for installation of switch sensor assembly across from lock 3 and in the path of the deadbolt. Snap off panel 12 on transmitter subassembly 11 permits access for changing batteries.

Figure 2 shows a hand held indicator, such as key fob 15, with inquiry input, such as switch button 18, first sensory perceptible indicator, such as green indicator LED 19 and second sensory perceptible indicator, such as red flashing LED 20. Optional key ring 16 permits attachment to keys or other items.

Figures 3-5 show details of the switch sensor assembly 10 and its installation on a door jamb. Figure 3 is a detail showing deadbolt 25 in its locked position extending (in dashed lines) beyond the location of switch assembly 10 on molding 7 which is typically at the edge of the door jamb. If there is no molding, the installation may be slightly simplified. In the crossection of Figure 4, hole 26 (preferably approximately 1/4" diameter) can be seen going through the molding 7 and beyond into the cavity that receives deadbolt 25. This is the only hole necessary for the installation. Both transmitter subassembly 11 and switch sensor assembly 10 are attached using a fastener means, such as a pressure sensitive foam adhesive layer which is exposed after the customer peels away a release liner. Other fasteners such as hook and loop VELCRO® can be alternately used. Since the thickness of the door jamb and molding 7 (if encountered) is a variable, switch assembly 10 is adjustable to accommodate these variables. In the exploded view of Figure 5, hollow guide 32, preferably a plastic molding with external threads, is engaged with threaded thick base 31, another molded part, and is also threaded into lock nut 36. Guide 32 fits into hole 26 (see Figure 4) and is adjusted by screwing base 31 so that a contact portion, such as hemispherical tip 33 of an actuator, such as actuator rod 38 is pushed a short distance by impingement with the side surface of deadbolt 25, thereby pushing actuator rod 38 away from the distal end within hollow guide 32 thereby actuating switch 39 bonded within snap housing 34. The correct distance for reliable operation, "L", is then locked by a further fastener, such as by screwing a fastener, such as a lock nut 36, down into contact with base 31. Note that actuator rod 38 is prevented from exiting guide 32 at its distal end because the reduced diameter exit hole at that end (not shown) impinges on step 40. Optional flange 37 on guide 32 permits snap housing 34 to snap over and engage guide 32 while still permitting rotation of cap 34 so as to rotate it to properly guide the two conductor cable which will be attached inside transmitter housing 11. Note that a press fit closure, such as foam adhesive layer 30, is used to attach base 31 (and thereby assembly 10) to the surface of molding 7. To complete the installation of switch assembly 10, optional dust cap 35 is rotated so that the cable is in registration with "mousehole" notch 41 and then fitted over base 31 with a friction fit.

Figure 6 shows block diagrams of transmitter subassembly 11 as well as key fob 15. Regarding transmitter subassembly 11, battery 50 is routed through switch sensor 39 into a power distribution block 51 which typically incorporates a MOSFET element. Thus power is preferably made available to transmitter 53, single shot timer 52, and pulse modulator 54. When timer 52 times out its interval (preferably 5 minutes or less), it signals power distribution block 51 to disable power to all of the elements. Transmitter 53 is simple enough to be assembled of discrete components especially since there are no stringent size constraints, but a single integrated circuit transmitter such as the nRF2404 from Nordic Semiconductor (Tiller, Norway) can be used instead. Both blocks 52 and 54 can be can be built using CMOS integrated circuit timers such as the infamous "556" series, but both blocks can be software implemented using a single appliance grade 8-bit microprocessor instead. Key fob 15 uses a low voltage power source, such as, for example, button cell 59 for power. User input is preferably achieved by momentary push button switch 18, which serves the "inquiry" function powering receiver 57 and pulse integrator 58 to energize either green LED 19 if an RF signal had been detected or alternatively flashing red LED 20 if no signal had been detected. Receiver 57 would benefit from being a single chip integrated circuit due to the reduced space within key fob 15. Other display options besides LED's are available including liquid crystal geometric or alpha types.

In the alternate embodiment shown in Figures 7-9, a metal strike plate 65 framing the deadbolt opening normally attached to the door jamb has been modified with extensions 69 to accept a low profile switch sensor 70 which is permanently bonded to it. In Figure 7, metal strike plate 65 with mounting holes 67 and deadbolt opening 66 is shown with rounded edge cowling 68 which smoothly guides bolt 25 into hole 66. Figure 8 clearly shows extension fingers 69 which emanate from cowling 68 to form a bonding anchor for switch sensor 70. Switch 70 is attached to transmitter subassembly 11 via dual conductor 71 which is passed through a small diameter hole (approximately 3/32") to the interior of the door jamb. No adjustment of the switch sensor is necessary as its actuation dome 72 (see Figure 9) is strategically located to be depressed by bolt 25 when it is deployed through plate 65 to lock the door.

In the alternate embodiment of Figures 10-12, building door 104 is locked with a key engaging deadbolt lock 106 within door 104. Door lock 106 has a movable deadbolt (not shown) for locking the door 104. Upon activation by the key, the deadbolt moves from a retracted unlocked position inside the housing of deadbolt lock 106, which is located within the door 104, to an extended locking position when the deadbolt penetrates a recess in the door jamb in wall 103 surrounding the door 104, thereby preventing the door 104 from opening.

The deadbolt lock reminder system comprises a normally closed deadbolt detector switch 121 which supplies power from battery 120 to a proximity detector 122 detecting the presence of a person in the vicinity of the door 104 whenever the deadbolt is not locked,

a) wherein when the person leaves the vicinity of the door 104, the proximity detector 122 switches into a "person no longer detected" mode ,

b) wherein further an alarm 129 will commence sounding reminding the person to return to lock the deadbolt 106 while the person is still within earshot of the alarm 129. A deadbolt lock proximity detector reminder system 101 is shown in Figure 10 mounted adjacent a door 104 on an outside wall 103. A housing contains all components except for the deadbolt switch which is in the deadbolt recess in line with lock 106, and wired to system 101 via wire 102 in the door jamb. The front surface of housing 101 is conductive, and therefore acts as the detection surface. An extension surface inside the door jamb and partially inside may be required for acceptable performance in some cases. Door knob 105 is in its typical location with optional snap latch lockset.

Figure 11 depicts an alternative embodiment of deadbolt reminder system 101, which is mounted at the door 104, but the housing for most of the components is inside. A conductive capacitive plate extension 110 wraps around the door jamb shown in Figure 11 from outside to inside and is then wired to the indoor housing. A two wire cable 112 consisting of two wires in a cable in Fig. 11 leads from the indoor housing to a loud externally mounted sound emitter 111, such as a piezoelectric type. Plate 110 can be easily made of an insulating layer with an adhesive on its back side (with release liner) and a thin aluminum foil outer layer. The foil layer may be painted with a flat finish.

A functional circuit block diagram for the alternate embodiment for a reminder system 101 with a proximity detector is depicted in Figure 12. The circuit includes a battery 120 that powers the reminder system 101. Switch 121, as shown, is equivalent to the deadbolt locked position detection switch, which enables the battery 120 to power the entire system, only when the deadbolt is unlocked (since it is a normally closed switch opened by being impinged upon by the deadbolt in its locking recess). The operation is described assuming the deadbolt is unlocked. A capacitive proximity detector 122 as shown includes a capacitive detection plate 123 which is used to detect the presence of a person in the vicinity of the detector. Output 124 is enabled if the capacitance drops to a voltage level below the threshold of "No person Detected".

At that point, a first single shot (SSl) 125 is triggered, an output of which immediately goes high for a predetermined period of time, such as, about a second. The output signal is inverted at inverter ("I") 126, the inverted signal fed to one input of "AND" circuit 127. The other input to AND circuit 127 is the "ND" signal 124.

Consequently, the output of "AND" circuit 127 is inhibited as long as single shot 125 has not timed out, or the non detection signal is no longer valid. If the condition of the single shot (SSl) 125 has timed out, and "ND" signal 124 is still valid, the output of "AND" circuit 127 switches high thereby triggering single shot (SS2) 128. The triggering times out the signal to a sound emitter 129, which sounds for the set length of further single shot (SS2; 128). A second smaller (or less loud) optional indoor alarm 130 is shown in dashed lines, which is used in an alternative embodiment.

In another alternate embodiment shown in Figures 13-17, Figure 13 shows the exterior of door 201 in wall 202 of any house, store, warehouse, apartment, etc. Door knob 203 and deadbolt lock 204 are shown below a transmitter subsystem 210 of this invention.

Figure 14 shows an end view detail of door 201 showing the close proximity of a hand held receiver subsystem 215 to deadbolt lock 204 and deadbolt 205. In the embodiment shown, hand held receiver subsystem 215 comprises a key fob. Transmitter subsystem 210 transmits a reminder signal to the hand held receiver subsystem 215 when key 206 is in deadbolt lock 204. Preferably, a connector includes a pair of contacts, such as, for example, spring contacts 211. The spring contacts overlap the edge of door 201 and are connected to transmitter subsystem 210. The contacts 211 are used to connect a sensor, such as a sensor switch in a door jamb recess when door 201 is closed.

Alternatively, transmitter subsystem 210 can be located elsewhere in the vicinity of the deadbolt lock 204 and deadbolt 205, such as to the wall across from deadbolt lock 204 to eliminate the need for contacts 211. Since the hand held receiver subsystem, such as key fob 215, is preferably attached via key chain 207, or other receiver housing, this important close proximity is easily maintained.

Also shown in Figure 14 is snap lock tang 208 and deadbolt 205 in a retracted position. Shown on the hand held receiver subsystem 215, such as key fob, are time and date display 216, and a user input device 217, such as, for example, momentary switch button (which preferably must be pressed to display time and date).

Figure 15 is a block diagram of the various electrical components comprising the circuitry for both subsystems. The hand held receiver subsystem 215, such as, for example, the key fob as shown comprises an antenna 235 connected to a passive receiver 236, and a time display 216. Each device is powered by power supply 237, preferably a DC cell. Alternatively, the hand-held receiver subsystem can be powered as are known RFID devices, i.e., powered and activated by received RPID signals.

The time and date signal may be displayed, and/or stored in a memory found in the passive time display 216, or in non-volatile storage in passive receiver 236. Old messages are simply overwritten to avoid clutter of old messages. That is, preferably, older data is simply overlaid by new data. When the input device 217, such as the momentary push button shown, is energized, the stored time/date data is displayed in the time display 216. The preferred display technology is LCD although other visual, auditory or tactile

(vibrating) technologies such as LED may be used alone or in combination.

Transmitter subsystem 210 uses a power source 226, such as, for example, the internal battery as shown (e.g., 2-4 AA alkaline cells). Power control module 227 powers transmitter block 228 for a period sufficient for data transmission and then shuts off power. Transmission is initiated by the closing of a sensor 225, such as the deadbolt sensor switch as shown. Real-time clock module 229 is "always on" and supplies the time and date to be transmitted. The reminder signal generated for transmission by the transmitter 228 is sent via antenna 230, as mentioned, for receipt with antenna 235 in the hand held receiver subsystem 215.

In an alternate embodiment, both transmitter block 228 as well as passive receiver 236 are replaced by transceivers so that an acknowledgment signal can be sent back to therebetween to verifying good reception of time/date data within the reminder signal. A retransmission can commence at the transmitter subsystem 210 if no acknowledgment is received thereat shortly after transmission. The RF signal still powers block 236 even if replaced by a transceiver (as in typical RFID applications).

In another alternate embodiment, shown in Figures 16 and 17, a different method is used to convey locked/unlocked information to the user. In the detail of Figure 16, transmitter subsystem 350 is mounted in the vicinity of the deadbolt lock 304, such as, for example, on the stationary wall 302 as shown. Deadbolt 305 and sensor switch 325 are shown in phantom view within the recess in the door jamb (in a locked position), optionally located underneath transmitter subsystem 350. In this manner, no pairs of contacts, such as contacts 211, as required in the embodiment shown in Figures 13 and 14, are needed to connect transmitter subsystem 350 to switch 325 (i.e.,, contacts both reside on the same side of the door/jamb interface). Note that the hand held receiver subsystem 360, such as the key fob as shown, no pushbutton is included (or required) as the display 361 continuously indicates elapsed time since the last lock operation.

In Figure 17, transmitter 328 is just used to emit the reminder signal, such as a single RF burst, when the power control module 327 senses switch 325 closing (upon impingement by deadbolt 305). Transmitter 328 is then shut down. Passive receiver 336 in the hand held receiver subsystem 360, such as, for example, the key fob as shown, is powered by the energy comprising the RF burst, and responds by sending a reset pulse to elapsed time counter 362. Please note that elapsed time counter 362 is continuously powered by a power source 363, such as the button cells as shown. Elapsed time display 361 displays the count, such as, for example, as hours and minutes.

A standard stop watch module with integral display can be used, but its physical length and "not useful" seconds display may dictate against it. If a normal wrist watch time display is used with a limitation of "blank" or "1" for the high order digit, the maximum elapsed time that can be displayed would be 19 hours and 59 minutes. This should be sufficient for the present application. After that, the overflow condition would be displayed as demarcation dots flashing once per second. It should be intuitive for a user to interpret elapsed time since departing from a locked door, relative to that since the last time the door site was actually visited; if they are approximately the same, the door had been properly locked.

In another further alternative embodiment shown in Figure 18, the communications protocol between the transmitter subsystem and the passive receiver is enhanced by utilizing a common unique factory selected code. The transmitter sends this code during its brief burst when the deadbolt is locked. This code is then received by the passive receiver 336 and compared to the code stored within. If a match is detected, the elapsed time counter 362 is reset. This procedure is described by the flow chart of Figure 18. Although interference with the passive receiver 336 should be rare, a person with a key fob 360 of this invention could be in an environment where RFID readers of the same frequency band are in use, such as a retail or factory/warehouse area. Also, possibly a second person standing at a door being locked which uses this reminder system may himself be carrying a key fob from a similar reminder system for his own door; stray transmitter signal could reset the elapsed time counter of the second key fob. These cases of inadvertent resetting would be avoided by the code scheme.

In yet another further alternate embodiment of these reminder systems (either the time stamp or uncoded/coded elapsed time counter systems of this invention), the reminder system is integrated with a deadbolt lock. One would simply install the lock with the reminder system as part of the normal procedure of "changing or installing" a lock in a door 400.

Figure 19 shows all of the parts of the lock that are unchanged from those of a "normal" deadbolt lockset. These standard parts are the lock cylinder 470, cylinder housing 471, thumbturn inside actuator 472 (or second interior cylinder), door jamb strike plate 473 and keys 474.

Figure 20 shows the deadbolt latch 475 of this invention which has two small modifications to support the reminder function. These modifications are as follows. A follower plate 476 that moves in unison with the deadbolt itself has a hole 477 added to accept bottom anchor portion 483 of the trigger assembly 480 shown in Figure 21. The other modification to deadbolt latch 475 is a shallow blind hole or depression 478 on one or both sides to locate and engage a spring clip bonded to the sensor switch.

A major added reminder system component to be incorporated into the lock system of this further embodiment is transmitter subassembly 490 shown in Figure 22. A non- conductive substrate 491 bonded to metal ring 489 serves as a base for transmitter housing 494 with removable battery access panel 495. The inside diameter 493 of metal ring 489 matches that of the door cylinder opening (typically 2 1/8" or 54mm). Ring 489 has a top flange 492 (over substrate 491) and a depressed ring surface 498 (see Figure 22). Surface 498 and the inner diameter of flange 492 are sized to accept the bottom surface of either housing 471 or inside actuator 472 (which are the same size). The back side of substrate 491 has an area of adhesive foam tape with release liner under transmitter housing region (not shown). Note prewired (dangling) sensor switch 496 with bonded spring clips 499. Notch 497 in metal ring 489 provides a path for the two-conductor cable attached to switch 496 to enter door hole 493 under the edge of housing 471 or inside actuator 472.

Trigger assembly 480 (Figure 21) consists of resilient trigger rod 481, anchor portion 483 and spring clip 482. It may be fabricated from spring wire and spring tempered sheet, or preferably as an injection molded plastic part. The function of this assembly 480 is to strike the actuator of switch 496 when the bolt (and plate 476) are moved forward to the locked position. Rod 481 is retained or "plugged into" hole 477 at bottom extension 483 and held in place by clip 482 around the edge of plate 476. Alternatively, hole 477 can be threaded and a threaded rod 481 can be simply screwed into it. Figure 24 shows a view of the working relation of trigger 480 and switch 496 as mounted to deadbolt latch 475. Note that the resilience of rod 481 makes it more conformable to the rounded contour of the space when bolt is retracted. Switch 496 is preferably a subminiature snap-action switch such as type MDS002 from C&K Company.

By having the factory precisely locate the working relationship between switch 496 and trigger 480, both mounted on deadbolt latch 475, the enhanced lockset can be used with transmitter subassembly mounted on the inside (as shown in Figure 25), or mounted on the outside of the door 400 as shown in Figure 26. The hinging of the door 400 (left or right) has no bearing on the installation of the enhanced lockset.

Alternatively, the transmitter assembly can be mounted within a hollow portion of the door 400, if the door 400 is a hollow door, or optionally within the hollow cylinder hole 493 provided within a door 400 for installation of a lock therethrough (as shown in Figure 24), where the transmitter assembly 494 is miniaturized and sized to fit within the pre-drilled hollow cylindrical hole 493 within the door 400 for insertion of the lock assembly therethrough, with respective inside and outside door knobs extending on either side of the door 400 from the inner lock assembly .

The few extra installation steps for the enhanced lockset with integral reminder system are detailed in the flow chart of Figure 27. Before installation, the user must decide if the transmitter subsystem is to be installed on the inside or outside of the door 400. On a wooden or fiberglass door 400, either location should function adequately as the transmitter signal would easily penetrate from an inside location to the outside. On a metal clad door, an outside location for the transmitter subsystem is required since the door 400 would shield the transmitter signal. Outdoor mounting of the transmitter must be evaluated based on possibility of vandalism, whether the door surface is shielded from sun and rain, and aesthetic aspects. The use of metal ring 489 in the transmitter subassembly insures that no compromise on lock security is introduced by the reminder system whichever mounting location is selected.

The next step is to remove the release liner from the sticky foam tape surface on the back of substrate 491. Then subassembly 410 is carefully mounted on the selected inside or outside surface in registration with the cylinder hole 493 in the door 400. Deadbolt latch 475 is then operated to retract bolt. Then it is pushed into edge hole in door and rotated 90 degrees (horizontal) to facilitate installation of trigger 480 and switch 496 through the side of hole 493. (This step is required since deadbolt latch 475 cannot fit through the door edge mounting hole if trigger 480 and/or switch 496 are preattached to it.) Then it is rotated vertically and screwed into the door edge. These should be the only extra steps in adding the reminder subsystem to the lock. No extra holes are required; no sensor switch alignment is required. The normal steps of attaching the cylinder and housing as well as thumbturn actuator (or second indoor cylinder) to complete the installation will proceed as normal. In the foregoing description, certain terms and visual depictions are used to illustrate the preferred embodiment. However, no unnecessary limitations are to be construed by the terms used or illustrations depicted, beyond what is shown in the prior art, since the terms and illustrations are exemplary only, and are not meant to limit the scope of the present invention.

It is further known that other modifications may be made to the present invention, without departing the scope of the invention, as noted in the appended Claims.

Claims

I CLAIM:

1. A low-cost wireless electronic system for notifying a user of a locked/unlocked position of a deadbolt used for securing a door to a door frame, comprising:

a switch sensor for mounting proximate a recess in the door frame, the recess configured to receive the deadbolt, wherein the switch sensor senses the deadbolt locked position and generates a "locked" indicator signal when the deadbolt is initially placed in a locked position;

a transmitter unit including a transmitter that is electrically connected to the switch sensor for receiving the locked signal, and transmitting a status signal identifying the deadbolt is in its locked position in response thereto, said transmitter unit being provided with a self shut-off feature operating after a fixed duration of minutes length has elapsed; and

a key fob including an inquiry key, a status indicator for indicating a

locked/unlocked status of the deadbolt, and a receiver in said key fob capable of receiving the transmitted locked status signal, wherein the receiver is activated to receive the locked status signal from said transmitter only after an inquiry key on its surface is pressed; and, said receiver having two sensory perceptible indicators for displaying said deadbolt status as locked or unlocked.

2. The low cost wireless electronic system as set forth in Claim 1, wherein said transmitter is pulse width modulated to vary a duty cycle of the transmitted status signal.

3. The low cost wireless electronic system as set forth in Claim 1 wherein said status indicator comprises at least one LED.

4. The low cost wireless electronic system as set forth in Claim 1 wherein said switch sensor comprises an integral part that further includes a metal strike plate deadbolt frame, wherein the switch sensor is bonded to said deadbolt frame.

5. The low cost wireless electronic system as set forth in Claim 4, wherein said switch sensor is concealably disposed within an access hole through which said deadbolt is inserted in a locking position.

6. The low cost wireless electronic system as set forth in Claim 1 wherein said switch sensor is a low profile, dome operated switch.

7. The low cost wireless electronic system as set forth in Claim 6 wherein a two- conductor cable connects said switch sensor to said transmitter.

8. The low cost wireless electronic system as set forth in Claim 1, further comprising a DC power source connected to the switch sensor and transmitter.

9. The low cost wireless electronic system as set forth in Claim 1, further comprising logical circuitry connected to both the transmitter and the switch sensor.

10. The low cost wireless electronic system as set forth in Claim 1, wherein the key fob further comprises logical circuitry and a battery, wherein the battery powers the logical circuitry, the status indicator, the inquiry key and the receiver.

11. The low cost wireless electronic system as set forth in Claim 9, wherein the logical circuitry controls the transmitter to transmit the "locked" status signal for a fixed time period.

12. The low cost wireless electronic system as set forth in Claim 11, wherein the logical circuitry responds to the "locked" signal generated by the switch sensor to control the transmitter to transmit for a fixed length of time.

13. The low cost wireless electronic system as set forth in Claim 12, wherein the logical circuitry controls the transmitter to transmit the locked status signal.

14. The low cost wireless electronic system as set forth in Claim 10, wherein inquiry key generates an inquiry signal upon depression by a user, and the logical circuitry within the key fob activates the receiver only when the inquiry signal is present.

15. The low cost wireless electronic system as set forth in Claim 14, wherein the logical circuitry within the key fob controls the receiver to actively receive periodically, for some portion of a receiving period that is equivalent to the fixed period of time for which the transmitter transmits in response to the switch sensor sensing a change in position of the deadbolt to the locked state.

16. A low-cost deadbolt system for notifying a user when a deadbolt mounted upon a door to be secured is extended in a locking position within a door frame, comprising:

a deadbolt configured for mounting to the door;

a strike plate deadbolt frame configured to be fixedly attached to a door jamb opposed to the deadbolt when the deadbolt is mounted to the door, the strike plate including a cowling defining an access hole in the strike plate to allow the deadbolt to pass therethrough into a recess in the door jamb, when the deadbolt is moved in a locked position;

an electronic switch sensor that is fixedly attached to the strike plate for mounting proximate a recess in the door frame, the recess configured to receive the deadbolt, wherein the switch sensor senses the deadbolt upon moving into a locked position and generates a "locked" indicator signal;

a transmitter unit including a transmitter that is electrically connected to the switch sensor for receiving the locked indicator signal, and transmitting a locked status signal based thereon; and

a key fob including an inquiry key, a status indictor for indicating a

locked/unlocked status of the deadbolt, and a receiver for receiving the transmitted locked status signal, wherein the receiver is activated to receive the status signal only upon depression of the inquiry key.

17. The low cost deadbolt system as set forth in Claim 16, wherein the sensor switch is attached to the strike plate by two fingers extending rearward from the strike plate.

18. The low cost deadbolt system as set forth in Claim 16, wherein the sensor switch is a very low profile, dome operated switch.

19. The low cost deadbolt system as set forth in Claim 16, wherein the locked indicator signal is generated only upon a movement by the deadbolt into a locked position through the cowling, and the transmitter transmits the locked status signal only for fixed time period upon receipt of the locked indicator signal from the senor switch.

20. The low cost deadbolt system as set forth in Claim 19, wherein the transmitter transmits for 300 seconds.

21. The low cost deadbolt system as set forth in Claim 20, wherein the key fob receives the locked status signal only when the inquiry key is pressed.

22. A deadbolt lock reminder system, comprising:

a door having a deadbolt in a deadbolt lock for locking the door, said deadbolt moving from a retracted unlocked position inside said lock within said door to an extended locking position when said deadbolt penetrates a recess in the door jamb surrounding the door;

a proximity detector;

a normally closed deadbolt detector switch which supplies power from a battery to the proximity detector and detects a presence of a person in a vicinity of the door whenever the deadbolt is not arranged in a locked position,

wherein said proximity detector detects when said person leaves a vicinity of said door and therefore switches into a "person no longer detected" mode and triggers an alarm to remind said person to return to lock the deadbolt lock while said person is still within earshot of said alarm.

23. The deadbolt lock reminder as in Claim 22, wherein said normally closed proximity detector switch is placed in the deadbolt recess of said lock.

24. The deadbolt lock reminder as in Claim 23, wherein when said normally closed proximity detector switch is in its normally closed state, power is available from a battery source to operate said proximity detector and alarm circuitry.

25. The deadbolt lock reminder as in Claim 22, wherein said proximity detector is a capacitive type.

26. The deadbolt lock reminder as in Claim 22, wherein said normally closed proximity detector switch is ultrasonic.

27. The deadbolt lock reminder as in Claim 22, wherein said normally closed proximity detector switch is infrared.

28. The deadbolt reminder as in Claim 22, further comprising a microprocessor programmed to detect proximity using a motion detector.

29. The deadbolt reminder as in Claim 22, wherein as said person leaves through the door 4 at a time at which the deadbolt lock is an unlocked state, said proximity detector detects the presence of the person, wherein if the person locks the deadbolt lock, said proximity detector switch is opened thereby deactivating said proximity detector, and no alarm is sounded, and wherein if the person does not lock the deadbolt lock, a single shot timer with a short time delay period is triggered such that at the end of the short time delay period an alarm sounds for a predetermined timed period alerting the person that said lock is unlocked.

30. A deadbolt lock reminder system using a passive receive, whereby a person in a remote location can reference a display providing information relative to the last time said deadbolt was locked to help determine the present locked or unlocked condition of said lock comprising:

said movable deadbolt engageable with a normally open sensor switch, wherein the locking action is sensed by said sensor switch when said deadbolt physically engages said sensor switch thereby closing said sensor switch contacts upon said deadbolt entering a recess in the door jamb and by such action locking the door;

a transmitter subsystem mounted adjacent to said deadbolt lock is electrically wired to said sensor switch contacts causing a short, powerful RF transmission upon closing of said contacts;

a handheld subsystem in the vicinity of said transmitter subsystem powered by and receiving said RF transmission on a passive receiver within the housing of said handheld subsystem such that information relative to said locking action is now viewable on said display on the surface of said housing.

31. The deadbolt lock reminder system of Claim 30 wherein said transmitter subsystem is mounted on the door being locked.

32. The deadbolt lock reminder system of Claim 30 wherein said transmitter subsystem is mounted on a stationary wall adjacent to the door being locked.

33. The deadbolt lock reminder system of Claim 30 wherein said handheld subsystem housing is a key fob attached to the lock key used for locking said deadbolt lock.

34. The deadbolt lock reminder of Claim 30 wherein said transmitter subsystem includes a real-time day/date clock such that said RF transmission received by said handheld subsystem includes the time and date at the instant of locking said deadbolt lock, said information stored within said housing and is portable and accessible at any time or plane.

35. The deadbolt lock system of Claim 34 wherein said time and date at the instant of locking overlays previous data, thereby replacing the previous data stored within said housing.

36. The deadbolt lock of Claim 35 whereby said stored time and date is viewable constantly on said display.

37. The deadbolt lock system of Claim 35 whereby said stored time and date is viewable only upon pressing a display button upon the surface of said housing.

38. The deadbolt lock reminder system of Claim 30 wherein said handheld subsystem contains a free-running counter continuously displaying elapsed time on said display which said counter is reset by an RF transmission received on said passive receiver from said transmitter subsystem upon locking of said deadbolt lock thereby providing the elapsed hours and minutes since the last time the deadbolt was locked, said information is portable and accessible at any time or place.

39. The deadbolt lock reminder system of Claim 38 wherein in the case of an overflow condition of said elapsed time counter, respective digits in said display go blank but respective dots demarking hours and minutes continue to blink at a predetermined rate of time.

40. The deadbolt lock reminder system of Claim 38 wherein to prevent rare occasions where unintentional resetting of said free-running elapsed time counter may happen, a code matching scheme is used with an enhanced transmission burst;

wherein further said reminder system is produced such that said transmitter and said passive receivers in one or more key fobs are matched whereby a unique common factory-set code is used by both said transmitter and said passive receiver.

41. The reminder as in Claim 40 wherein said transmitter burst that awakens and powers said passive receiver also sends said code which said code is received and compared to a code imbedded in receiver electronics in said receiver,

wherein further only if there is a code match will said receiver reset said free- running elapsed time counter.

42. The reminder system as in Claim 30 wherein said reminder is incorporated into a deadbolt lock and sold as part of a total lock installation kit.

43. The reminder system as in Claim 42 wherein a single module incorporating the transmitter subsystem with a prewired sensor switch is installed as part of the lock and interacts with a modified deadbolt latch portion to which said sensor switch is then attached within the lock cylinder hole in the door without the need to drill extra holes to attach said sensor switch or to convey wires to said sensor switch.

44. The reminder system as in Claim 43 wherein said sensor switch is pre-aligned to said deadbolt during manufacture.

45. The reminder system as in Claim 42 wherein said transmitter is part of a transmitter subassembly comprising a non-conductive substrate bonded to a metal ring serving as a base for a transmitter housing with a removable battery access panel, wherein the inside diameter of said metal ring matches that of the door cylinder opening, said ring having a top flange over said substrate and a depressed ring surface, said surface and said inner diameter of said flange being sized to accept a bottom surface of either said housing or said inside actuator, wherein a back side of said substrate has an area of adhesion under said transmitter housing region, wherein a notch in said metal ring provides a path for a two-conductor cable attached to said switch to enter the door cylinder hole under a respective edge of either said housing or said inside actuator.

46. The reminder system as in Claim 45 further comprising a trigger assembly including a resilient trigger rod, an anchor portion and a spring clip, said trigger assembly striking the actuator of said switch when said bolt and said plate are moved forward to the locked position.

47. The reminder system as in Claim 46 wherein said rod is retained into said hole at said bottom anchor extension and held in place by one of a) said clip around an edge of said plate, or, b) said hole being threaded and a threaded rod being screwed into said hole.

48. The reminder system as in Claim 42 wherein said transmitter subassembly is mounted on an outside surface of said door.

49. The reminder system as in Claim 42 wherein said transmitter subassembly is mounted on an inside surface of said door.

50. The reminder system as in Claim 42 wherein said transmitter subassembly is mounted within a hollow portion of said door.

51. The reminder system as in Claim 42 wherein said transmitter subassembly is mounted within a door lock cylinder hole.