Patent Application
20050189805
1. Field of the Invention
The subject matter disclosed generally relates to a sensor that can sense when a child safety seat has been coupled to a seat of a vehicle.
2. Background Information
Infants and small children are typically placed within a child safety seat when traveling in a vehicle such as an automobile. The safety seat is strapped onto a seat with the seat belt of the vehicle.
There has been enacted legislation that will require all vehicles to have a ring that extends from between the seat cushions of a seat assembly. Child safety seats will have a corresponding latch that will snap onto the ring and secure the safety seat to the seat assembly. The ring must have a relatively low profile so that occupants of the vehicle can sit on the seat without discomfort when the child safety seat is not in use. The low profile makes it difficult to determine whether the safety seat latch has been properly attached to the ring.
There has been enacted legislation to require automobile manufacturers to disable the passive restraint system for occupants under a predetermined weight. Vehicles that comply with this legislation may have a weight sensor in the seat that senses the weight of the occupant and provides a feedback signal to the restraint system. Unfortunately, the new latch feature of the child safety seat may be tightened to create an improper reading of the occupant's weight. The additional tension force of the latch may increase the force sensed by the weight sensor so that the system mistakenly believes that an infant is an adult and remains enabled.
It would be desirable to provide a system that would indicate when a latch of a child safety seat has been attached to a seat assembly of a vehicle.
A sensor that can sense when a latch of a child safety seat has been coupled to a seat assembly.
Disclosed is a sensor for sensing when a latch of a child safety seat is coupled to a seat assembly of a vehicle. The sensor may include a first housing member that is mounted to a seat frame of the vehicle. The sensor may also include a second housing member that can move relative to the first housing member. A sensor subassembly may sense the relative movement of the second housing member. The latch of the child safety seat can be snapped onto a ring of the second housing member and subsequently tightened to secure the child seat to the vehicle. Coupling the child seat to the ring moves the second housing member relative to the first housing member. This movement is sensed by the sensor which provides an output signal. The output signal can be processed to provide an indication to the vehicle driver that the child seat has been coupled to the seat, and/or disable an airbag and/or disable a seat movement device.
Referring to the drawings more particularly by reference numbers,
As shown in
As shown in
The controller 30 may also disable the air bag 34 adjacent to the child seat 10. The air bag 34 may be disabled when the controller 30 determines that the child latch has been properly secured to the seat assembly. Additionally, movement of the seat assembly may stretch or even break the child seat strap. The controller 30 may also prevent movement of the seat when the latch is secured to the seat assembly. Seat movement may be inhibited by disabling the seat motor, engaging some type of mechanical latch, or other means.
The input signal from the sensor 20 may be a signal that has two levels, one level to indicate that the latch has not been properly attached and another level that the child seat has been properly attached. Alternatively, the input signal may have an amplitude that varies with the latch force sensed by the sensor 20. For example, the voltage of the input signal may vary between 0-5V for a load range of 0-30 lbs. The controller 30 can then determine whether the amplitude exceeds a threshold value and drive the display 32, accordingly. Although a controller 30 is shown and described, it is to be understood that the sensor 20 may provide the input signal directly to the display 32.
The second housing member 42 can move relative to the first housing member 40. The second housing member 42 includes the ring 24. The ring 24 can be formed with the second housing member 42 or attached to the housing member 42, for example with a welding process. The first housing member 40 may include stop surfaces 48 that engage flanges 50 of the second housing member 42 to limit the travel of the second member 42. A portion of the second housing member 42 may reside in a cavity 52 of the first housing member 40 to minimize the profile of the sensor 20.
The sensor 20 further includes a sensor subassembly 60 that senses movement of the second housing member 42. The subassembly 60 may include a magnet 62 and a Hall Effect sensor 64. Located between the magnet 62 and Hall Effect sensor 64 is an armature 66. The armature 66 is mounted to a restraining plate 68 that is attached to the second housing member 42. Movement of the second housing member 42 moves the armature 66 and changes the magnetic field sensed by the Hall Effect sensor 64. The Hall Effect sensor 64 provides an output signal on wires 70 that varies in accordance with movement of the armature 66 and second member 42. Although a Hall Effect sensor is shown and described, it is to be understood that other types of sensors such as force or pressure sensors may be employed.
The sensor 20 may include a biasing spring 72 that biases the second housing member 42 toward the magnet 62 and Hall Effect sensor 64. The spring 72 may be captured by a wall 74 of the first housing member 40 and the restraining plate 68. The spring 72 may be centered about button 76. The sensor subassembly 60 may be enclosed by a cover 78 that is attached to the first housing member 40 through fastener apertures 80.
In operation, the child seat latch is snapped onto the ring 24. The latch is tightened which causes a force in the direction indicated by the arrow shown in
While certain exemplary embodiments have been described and shown in the accompanying drawings, it is to be understood that such embodiments are merely illustrative of and not restrictive on the broad invention, and that this invention not be limited to the specific constructions and arrangements shown and described, since various other modifications may occur to those ordinarily skilled in the art.
