Electrical circuit module with magnetic detection of loose or detached state

• US 20030229431A1
• Filed: 06/06/2002
• Published: 12/11/2003
• Est. Priority Date: 06/06/2002
• Status: Active Grant

• Current Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Original Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Inventors: Koors, Mark A.
• Granted Patent: US 6,684,141 B2
• Time in Patent Office: Days
• US Class Current: 701/45
• 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 2/0031 mounted on the frame
• CPC Class Codes: B60N 2210/14 Inductive; Magnetic field
• CPC Class Codes: B60N 2210/40 Force or pressure sensors
• CPC Class Codes: B60N 2210/50 Inertial sensors
• CPC Class Codes: B60N 2220/20 using a deterministic algorithm
• CPC Class Codes: B60R 21/01512 Passenger detection systems
• CPC Class Codes: B60R 21/0156 by deceleration

Abstract

An electric circuit module has a case made of a non-magnetic material. The case has an attachment portion for fixed mounting on a vehicle part made of a magnetic material and a permanent magnet fixed within the case. The module further has a Hall effect sensor fixed within the case in positional relation to the permanent magnet and the attachment portion such that the Hall effect sensor generates a first signal when the attachment portion of the case is fixedly attached to the vehicle part and a second signal different from the first signal when the attachment portion of the case is not so mounted. The module also has an electric circuit in the case with circuit elements responsive to the Hall effect sensor to provide a first mode of operation in response to the first signal and a second mode of operation in response to the second signal. The module is particularly useful when at least one of the electric circuit elements is an accelerometer, for example in a vehicle passive restraint deployment system. In such an application, the Hall effect sensor output indicates the validity of the accelerometer output signal as an indication of accelerations of the vehicle part and can thus help control the use of the accelerometer signal in determining restraint deployment.

Claims

1. An electric circuit module adapted for attachment in a mounted position to a vehicle part comprising a magnetic material, the module comprising:

a case made of a non-magnetic material and having an attachment portion;

a permanent magnet fixed within the case;

a Hall effect sensor fixed within the case in positional relation to the permanent magnet and the attachment portion such that the Hall effect sensor generates a first signal when the attachment portion of the case is fixedly attached to a member comprising a magnetic material and a second signal different from the first signal when the attachment portion of the case is not so mounted; and

an electric circuit in the case comprising circuit elements responsive to the Hall effect sensor to provide a first mode of operation in response to the first signal and a second mode of operation in response to the second signal.

2. The electric circuit module of claim 1 in which the circuit elements comprise an accelerometer providing an output signal indicating an acceleration of the module, the output signal thus indicating acceleration of the portion of the vehicle body when fixedly attached thereto.

3. The electric circuit module of claim 2 in which the circuit elements responsive to the Hall effect sensor declare an output signal of the accelerometer to be valid when Hall effect sensor provides the first signal and alternatively declare the output signal of the accelerometer to be invalid when the Hall effect sensor provides the second signal.

4. The electric circuit module of claim 3 further having an electric circuit board fixedly disposed therein and mounting the electric circuit elements including the accelerometer, the Hall effect sensor and the magnet.

5. The electric circuit module of claim 4 in which the circuit elements are part of a vehicle occupant restraint deployment system.

6. A vehicle restraint deployment system comprising an electric circuit module fixedly attached in a mounted position to a vehicle part comprising a magnetic material, the module comprising:

a case made of a non-magnetic material and having an attachment portion;

a permanent magnet fixed within the case;

a Hall effect sensor fixed within the case in positional relation to the permanent magnet and the attachment portion such that the Hall effect sensor generates a first signal with the attachment portion of the case in the fixedly attached position but generates a second signal different from the first signal if the attachment portion of the case becomes not so fixedly attached; and

an electric circuit in the case comprising circuit elements responsive to the Hall effect sensor to provide a first mode of operation in response to the first signal and a second mode of operation in response to the second signal.

7. The electric circuit module of claim 6 in which one of the circuit elements is an accelerometer providing an output signal indicating an acceleration of the module, the output signal thus indicating acceleration of the portion of the vehicle body when fixedly attached thereto.

8. The electric circuit module of claim 7 in which the circuit elements responsive to the Hall effect sensor identify an output signal of the accelerometer as valid when Hall effect sensor provides the first signal and alternatively identifies the output signal of the accelerometer as invalid when the Hall effect sensor provides the second signal.

9. The electric circuit module of claim 8 further having an electric circuit board fixedly disposed therein and mounting the electric circuit elements including the accelerometer, the Hall effect sensor and the magnet.

10. The electric circuit module of claim 8 in which the module is fixedly attached to a vehicle seat pan comprising a ferrous material.