Key sensor alarm for door locks

• US 5,680,094 A
• Filed: 10/19/1995
• Issued: 10/21/1997
• Est. Priority Date: 09/22/1994
• Status: Expired due to Fees

• Current Assignee: Elena Guim, Raul Guim
• Original Assignee: Elena Guim, Raul Guim
• Inventors: Guim, Raul, Guim, Elena
• Primary Examiner(s): Hofsass, Jeffery
• Assistant Examiner(s): Lefkowitz, Edward
• Application Number:
  US08/545,141
• Time in Patent Office: 733 Days
• Field of Search: 340/332, 340/686, 340/568, 340/539, 340/542, 340/457, 340/691, 340/692, 340/407.1, 340/286.08, 70/DIG. 49
• US Class Current: 340/332
• CPC Class Codes: B60Q 9/00 Arrangement or adaptation of signal devices not provided for in one of main groups B60Q1/00 - B60Q7/00 , e.g. haptic signalling
• CPC Class Codes: E05B 11/00 Devices preventing keys from being removed from the lock ; Devices preventing falling or pushing out of keys preventing turning of the key E05B13/00; keyhole guards E05B17/14; E05B35/086 takes precedence
• CPC Class Codes: E05B 43/005 Timer devices controlling electrically operated locks
• CPC Class Codes: E05B 45/0605 for preventing of leaving the key key ejection E05B63/003
• CPC Class Codes: E05B 45/10 by introducing the key or another object
• CPC Class Codes: G08B 21/24 Reminder alarms, e.g. anti-loss alarms

Abstract

A key reminder device for use in combination with a key lock mechanism having an adjustable timer with a predetermined timer interval electrically coupled to a replaced power supply. The timer is energized upon detection of a conventional key inserted into the key lock mechanism. Should the key remain in the key lock mechanism beyond a predetermined time, the timer will activate an audible alarm to remind the owner of the keys to remove them. Should the timer be set at a low level, the device operates to indicate the presence of a key. When used in combination with a visual indicator, the key reminder provides an indicator of door entry to the hearing impaired.

Claims

1. A key reminder device for use in combination with a key mechanization, said key reminder device comprising:

a power supply;

a timer means electrically coupled to said power supply;

a trigger arm hingedly disposed inside a key insertion slot of a key lock mechanism for detecting the insertion of a key into the key lock mechanism thereby initiating said timer, insertion of the key pivotally moving said trigger arm inside within the key insertion slot; and

an audible alarm operatively associated with said timer;

wherein insertion of a key in the key lock mechanism pivots said trigger arm thereby coupling said power supply to said timer completing a series electrical circuit for operating said audible alarm after a period of time to indicate that the key has been left in the key insertion slot.

2. The key reminder device according to claim 1 wherein said timer means uses a square wave oscillator connected to a decade counter to achieve an alarm delay after key insertion, and wherein said oscillator period controls the alarm duty cycle.

3. The key reminder device according to claim 1 wherein said timer means uses a square wave oscillator connected to a decade counter to achieve an alarm delay after key insertion, and uses a separate timer circuit to control the alarm duty cycle.

4. The key reminder device according to claim 3 wherein said timer means alarm delay is adjustable between 5 and 20 seconds.

5. The key reminder device according to claim 1 wherein said trigger arm is coupled to a normally open micro switch, for use in completing an electrical circuit from said power supply to said timer upon insertion of the key into said key lock mechanism.

6. The key reminder device according to claim 1 wherein said audible alarm is a piezo electric speaker.

7. The key reminder device according to claim 1 wherein said power supply is defined as a replaceable battery.

8. The key reminder device according to claim 1 including a visual indicator electrically coupled to said timer.

9. The key reminder device according to claim 1 including a means for indicating low battery power.

10. A key reminder device for use in combination with a key lock mechanism, said key reminder device comprising:

a housing having a control box and a circular detection ring securable about an outer circumference of a conventional key lock mechanism;

a battery power supply placed within said control box;

an adjustable timer means having a predetermined timer interval electrically coupled to said power supply;

an optical sensor having an emitter disposed in a side surface of said detection ring and a diametrically positioned receiver position to detect the placement of the key there between; and

an alarm means operatively associate with said timer;

wherein insertion of the key in the key lock mechanism interrupts said optical sensor between said emitter and receiver completes a series electrical circuit whereby exceeding the time interval causes operation of said alarm.

11. The key reminder device according to claim 10 wherein said housing is constructed of thermoplastic.

12. The key reminder device according to claim 10 wherein said housing is constructed of a polished metal.

13. A key reminder device used in combination with a key lock mechanism, said key reminder device comprising:

a power supply;

a timer means electrically coupled to said power supply;

an optical sensor means juxtapositioned to a key insertion slot of the key lock mechanism for detecting the insertion of a key into the key lock slot coupled to said timer;

an alarm means operatively associated with said timer;

wherein insertion of the key into the key lock slot interrupts a beam of said optical sensor completing a series electrical circuit for operating said alarm means after a period of time to indicate that a key has been left in the key insertion slot.

14. The key reminder device according to claim 13 wherein said optical sensor includes an emitter for directing an infrared beam across the key insertion slot for receipt by a receiver wherein key insertion interrupts said infrared beam for completion of an electrical contact.

15. A concealed key reminder device for giving an alarm for failure to draw a key out of a key lock mechanism, comprising:

a key lock mechanism positioned in a door cavity for securing the door in a fixed position when said key lock mechanism is placed in a locked position, said key lock mechanism defined by a key slot having a chamber with a coded key tumbler juxtapositioned along a length of said chamber receptive to a key having a complimentary surface for engaging said key tumbler allowing for the locking and unlocking of said mechanism;

a normally open micro-switch having a first contact and a second contact disposed in the cavity of the door, said first contact having a trigger arm positioned within said chamber and movable upon insertion of the key into said chamber electrically coupling said first contact to said second contact;

a replaceable power supply electrically coupled to said first contact;

a timer means electrically coupled to said second contact, said timer means having a predetermined timer interval initiated upon coupling to said power supply; and

an alarm means electrically coupled to said timer means producing an audible alarm upon completion of said timer interval;

wherein insertion of the key into the said key lock mechanism moves said trigger arm from said first position to said second position to complete an electrical contact between said power supply causing operation of said alarm after a period of time if the key remains in said key lock mechanism.