RFID buckle closure and presence sensor system for safety childseat

• US 20070096891A1
• Filed: 10/17/2006
• Published: 05/03/2007
• Est. Priority Date: 10/17/2005
• Status: Abandoned Application

• Current Assignee: Graco Children's Products, Inc. (Newell Brands Inc.)
• Original Assignee: Graco Children's Products, Inc. (Newell Brands Inc.)
• Inventors: Sheriff, Michael, Funk, Ethan
• Application Number:
  US11/581,884
• Publication Number:
  US 20070096891A1
• Time in Patent Office: Days
• US Class Current: 340/457.1
• CPC Class Codes: B60N 2/002 Seats provided with an occupancy detection means mounted therein or thereon detection means responsive to presence or absence of children B60N2/266
• CPC Class Codes: B60N 2/2812 for securing the child to the child seat
• CPC Class Codes: B60R 2022/4816 for sensing locking of buckle
• CPC Class Codes: B60R 2022/4858 for sensing pressure on seat
• CPC Class Codes: B60R 2022/4866 Displaying or indicating arrangements thereof
• CPC Class Codes: B60R 21/01556 Child-seat detection systems
• CPC Class Codes: B60R 22/48 Control systems, alarms, or interlock systems, for the correct application of the belt or harness

Abstract

In the preferred embodiment of the present invention a passive, wireless, RFID-based wireless buckle-closure sensor determines whether the buckle of a child safety seat is secured. Sensors also are provided to determine if the child is in the seat, the temperature and if the vehicle is in operation, and alarms are sounded if an unsafe condition is detected by the system. Child safety seats utilize a 3-point or 5-point locking-mechanism for seat belt and harness restraints. The locking-mechanism requires that metal belt/harness components latch together and are released by depression of a lock-mounted release button. In the preferred embodiment of the present invention a passive RF transponder is affixed to the buckle. Essentially the RF transponder comprises an RFID device without a data component. The RF transponder is interrogated by a frequency-scanning reader, which determines the resonant frequency of the transponder. The resonant frequency of the transponder is affected by the presence of the metal fittings local to the RF transponder. Thus, since the major components of the buckle and latch are metal, the detection of the change in the resonant frequency of the transponder, also referred to as “detuning,” permits the determination of the state of the belt/harness buckle—latched or unlatched. This sensing is wireless, unobtrusive, and requires only a passive component be attached to the buckle. Further disclosed is a method of determining the status of a child in a child safety seat, including: whether or not a child is in the seat, whether or not the belt/harness buckle is latched, whether the vehicle'"'"'s engine is in operation, and whether or not the surrounding temperature exceeds the temperature range. If an unsafe condition is detected, an alarm is activated.

Claims

1. A wireless detection system including:

a sensor antenna and a capacitor configured as a tank circuit for placement in a first position; and

a detector circuit including a detector antenna for wirelessly coupling to the sensor antenna and further including circuitry for placing an alternating current signal on the detector antenna;

sweeping the signal through a range of frequencies;

determining the resonant frequency of the tank circuit, and determining the presence of an inductor proximate to the sensor in response to the determined resonant frequency.

2. A child safety seat including a wireless detection system as in claim 1 for determining the status of the buckle closure.

3. A child safety seat including a wireless detection system as in claim 1 for determining the status of a child in the child safety seat.

4. A wireless proximity detection system including:

a sensor antenna and a capacitor configured as a tank circuit and

a detector circuit for wirelessly coupling to the sensor antenna and further including circuitry for placing an alternating current signal on the detector antenna;

sweeping the signal through a range of frequencies;

detecting the resonant frequency of the tank circuit; and

determining proximity of an inductor in response to the resonant frequency.

5. A child safety seat buckle closure system including;

a sensor antenna and a capacitor configured as a tank circuit; and

a detector circuit for wirelessly coupling to the sensor antenna and further including circuitry for placing an alternating current signal on the detector antenna;

sweeping the signal through a range of frequencies;

detecting the amplitude of the swept signal; and

determining the closure status of the buckle in response to the amplitude and frequency swept signal.