Seat-load measuring device

• US 20020185318A1
• Filed: 03/26/2002
• Published: 12/12/2002
• Est. Priority Date: 03/26/2001
• Status: Active Grant

• Current Assignee: Takata Corporation (Ningbo Junsheng Investment Group Co., Ltd.)
• Original Assignee: Takata Corporation (Ningbo Junsheng Investment Group Co., Ltd.)
• Inventors: Aoki, Hiroshi, Hida, Hirokazu
• Granted Patent: US 6,774,319 B2
• Time in Patent Office: Days
• US Class Current: 177/144
• 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 2/0025 by using weight measurement
• CPC Class Codes: B60N 2/0035 characterised by the sensor data transmission, e.g. wired connections or wireless transmitters therefor; characterised by the sensor data processing, e.g. seat sensor signal amplification or electric circuits for providing seat sensor information
• CPC Class Codes: G01G 19/4142 for controlling activation of safety devices, e.g. airbag systems electrical circuits for triggering safety arrangements in case of vehicle accidents B60R21/015
• CPC Class Codes: G01G 23/3707 using a microprocessor

Abstract

A seat-load measuring device for measuring a weight of a passenger and an object sitting on a car seat includes a load sensor disposed under the seat for electrically sending a load data, a first data processing unit having a predetermined response time, a second data processing unit having a slower response time than that of the first data processing unit, a detecting device for detecting a change in the load data, and a switching device electrically connected to the detecting means, the first and the second data processing unit for switching between the first and the second data processing unit to process the load data from the load sensor.

Claims

1. A seat-load measuring device for measuring a weight of a passenger and an object sitting on a car seat, comprising:

a load sensor disposed under the seat for electrically sending a load data,

a first data processing unit electrically connected to the load sensor and having a predetermined response time,

a second data processing unit electrically connected to the load sensor and having a slower response time than that of the first data processing unit,

detecting means electrically connected the load sensor, the first and the second data processing unit for detecting a change in the load data, and

switching means electrically connected to the detecting means, the first and the second data processing unit for switching between the first and the second data processing unit to process the load data from the load sensor.

2. A seat-load measuring device according to claim 1, wherein said switching means switches to the first processing unit from the second processing unit after a first predetermined period of time when the detecting means detects that the change in the load data exceeds a first predetermined value.

3. A seat-load measuring device according to claim 1, wherein said first data processing unit is a first filter having a predetermined time constant, said second data processing unit is a second filter having a slower time constant than that of the first filter, and said switching means switches to the first processing unit from the second processing unit at a timing determined by a difference between outputs of the first filter and the second filter.

4. A seat-load measuring device according to claim 2, wherein said second data processing unit includes a digital filter having a variable filter value to change a response time of the digital filter, and said switching device changes the variable filter value such that the difference between outputs of the first filter and the second filter becomes smaller when the switching means switches to the first processing unit from the second processing unit.

5. A seat-load measuring device according to claim 1, wherein said switching means switches to the second processing unit from the first processing unit when the detecting means detects the load data exceeds a predetermined load.

6. A seat-load measuring device for measuring a weight of a passenger and an object sitting on a car seat, comprising:

a load sensor disposed under the seat for electrically sending a load data,

detecting means electrically connected the load sensor for detecting a change in the load data, and

data holding means electrically connected to the load sensor and the detecting means for holding the load date for a second predetermined period of time and outputting the held load data when the detecting means detects that the change in the load data exceeds a second predetermined value, said second predetermined period of time being adjusted based on the change in the load data.

7. A seat-load measuring device according to claim 6, further comprising a plurality of filters having different time constants, said second predetermined period of time being adjusted based on a difference between outputs of at least two of the filters.

8. A seat-load measuring device according to claim 7, wherein said filters are digital filters having different time constants, further comprising switching means for switching to one of the digital filters having a larger time constant than those of the other after the second predetermined time period.

9. A seat-load measuring device according to claim 7, wherein one of said filters is an analog filter whose time constant can be changed by changing an electrical constant of a part constituting said analog filter.

10. A seat-load measuring device according to claim 6, further comprising software for processing the load data with slow and fast response times, said second predetermined period of time being adjusted based on a difference between the load data processed with the slow response time and with the fast response time.