JPH05223841A - Safety speed variation sensor - Google Patents

Abstract

PURPOSE: To obtain a safe sensor for detecting a speed change inexpensively by bending a first contact means toward a second contact means in response to deceleration by an inertia member. CONSTITUTION: A safety sensor 12 can be arranged on the refractory wall of a car and upper blades 50, 52 energize a spherical member 34 to bring the same into contact with a wall 30. A sensor 12 is arranged so that the spherical member 34 is energized in the direction shown by an arrow A when a car is decelerated. When this deceleration is larger than a predetermined threshold value, deceleration force overcomes the energizing force and the spherical member 34 is protruded in the direction shown by an arrow A along a passage 40 to come into contact with the leading end parts of the blades 50, 52. The spherical member 34 bends the blades 50, 52 in the same direction when moved in the A-direction until the blades 50, 52 come into contact with bent parts 58, 60. Therefore, electric circuits are formed between the blades 48, 50 and 46, 52 and these passages are used in the generation of an electric signal. These signals are sent to the sensor 12 from a plug 94.

Description

Detailed Description of the Invention

[0001]

RELATED APPLICATION This application corresponds to a partial continuation application of U.S. Application No. 423,871 filed October 19, 1989 under the name "Velocity Change Sensor with Bipolar Sensor". The subject matter of this application is further related to the following US applications owned by the same assignee: Name Application number Filing date Speed change sensor with spring bias 447,108 12/6/89 Speed change sensor with contact locking member 417,914 10/6/89 Speed change sensor with magnetic field concentrator and director 418 , 147 10/6/89 Speed change sensor with improved spring bias 587, 262 9/24/90

[0002]

BACKGROUND OF THE INVENTION 1. FIELD OF THE INVENTION The present invention relates to speed change sensors or accelerometers used in motor vehicles to detect sudden speed changes and in response thereto activate occupant restraint systems such as airbag systems. More particularly, the present invention relates to safety sensors that include an element that moves to a set position to activate a pair of contact blades in response to a sudden deceleration.

2. Background Art As a result of research, injuries due to car accidents (especially at high speed)
It has been found that the use of occupant restraint systems can be significantly reduced (the term "occupant" also includes the driver of the vehicle). These systems have an inflatable balloon (commonly referred to as an airbag) housed in an instrument panel or steering wheel. When a car undergoes a sudden deceleration, the airbag inflates and cushions the occupant, restrains their movements, and also those of the occupant and the vehicle (front glass, steering wheel, instrument panel, etc.) Automatically expands to a position that prevents contact with. Of course, a key element of these systems is a velocity change sensor or accelerometer that triggers inflation and deployment of the airbag. The movement of the vehicle must be carefully and accurately monitored so that the airbag can be quickly deployed before the occupant is seriously injured.

A velocity change sensor is disclosed in US Pat. No. 4,329,549 assigned to the assignee of this application. The sensor has a tubular housing that encloses a metal shell, a metal sphere, and a magnet that biases the sphere toward the first end of the shell. A second end of the shell is provided with a pair of electrical contact blades. The orientation of this sensor within the vehicle is determined so that the sphere moves from the first end to the second end and contacts the two blades when the vehicle experiences a deceleration above a set level. There is. Since the blade and the sphere are made of a conductive material, an electrical path is formed between the two blades when the sphere contacts the blade. This electrical path is used to generate an airbag deployment signal. A problem with the prior art is system safety. While the deployment of airbags in a crash is important to ensure occupant protection, preventing false deployment is just as important. Once deployed, the airbag significantly impedes driver movement.

[0005]

OBJECTS AND SUMMARY OF THE INVENTION In view of the above disadvantages of the prior art, it is an object of the present invention to provide a restraint system with an inexpensive safety sensor that provides redundancy against the action of restraint sysms. Another object is to provide a restraint system that includes a safety sensor configured to cause an inertial moving element (inertial member) to contact two electrical contact blades at substantially the same time.

Other objects and advantages of this invention will be apparent from the following description. The accelerometer of this invention is
A housing having at least a pair of contact blades;
An inertia member that moves in a predetermined path in response to a change in speed of the vehicle. The two contact blades are arranged in the movement path of the inertial member so that a direct electrical path is formed through the contact of the inertial member. In one aspect, a collision is detected when electrical contact is made through the inertial member. In another aspect, one contact is bent under the influence of the inertia member to contact the other contact. the important thing is,
The movement of the inertial member is not damped in order to ensure a rapid operation of the sensor.

[0007]

[Example] In order to clarify the action of the safety sensor,
FIG. 1 showing a block diagram of the occupant restraint system 10 will be described. This restraint system consists of a primary (identification) sensor 1
4 has a safety sensor 12 coupled to it. Primary sensor 1
4 is an inflating device 16 for inflating the airbag 18.
To start. The primary sensor 14 may be a braking sensor configured to identify crashes, i.e. distinguish between low speed and high speed crashes.

Next, referring to the other figures, the safety sensor 12 of the present invention is usually arranged in an automobile (not shown). The safety sensor 12 includes a tubular portion 20 having a flared end 22 and an open end 24 closed with potting material.
Have. The joint between plug 28 and end 24 may be sealed by other means. The plug 28 is arranged adjacent to the potting portion 26 having the spherical recess 30. The tubular portion 20 is preferably formed of a plastic material and has a metal sphere 34.
Hold an inertial member such as. The diverging end 22 has an outer peripheral flange 32 and is covered by a holding member 44 arranged in the axial direction. The holding member 44 can be attached to the tubular portion 20 by a known means such as an adhesive or pressure bonding. Four blades 46, 48, 50, 52 are attached to the holding member 40. For convenience, the blade 46,
48 is called a lower blade, and blades 50 and 52 are called upper blades. Each of these blades has a straight portion that passes through the hole 56 of the holding member 40. Each blade is held in place by an insulating bushing such as bushing 54 and is made of a relatively thin and flat conductive material such as copper. As shown in FIG. 2, the lower blades 46, 4
The upper end of 8 has curved portions 58 and 60. The upper blades 50 and 52 further extend inward in the radial direction, and
0 passage 40 and its tips 62, 64 are preferably formed of an insulating material such as a plastic material. Further, as an alternative, the sphere 34 may be coated with an insulating material. Shoulders 66 and 68 for setting the blades 46 and 48 to the positions shown in FIG.

The passage 40 is defined by a plurality of ribs 70, and the sphere 34 does not undergo significant aerodynamic damping.
To guide you. A stopper 72 having a spherical inner surface 74 facing the surface 30 is attached to the holding member 44. Face 7
The radii of curvature of 4, 30 are equal to the radius of the sphere 34. An outer cap 80 is secured to the flange 32, which together with the flange 32 and the inner retaining member 44 form a chamber 82. A printed circuit board 84 used to mount various circuit components such as resistors 86 is located within chamber 82. The blades 46, 48, 50, 52 extend into this plate 84 as shown. The cap 80 has mounting tabs 88 for mounting the sensor 10 to the fireproof wall 90 of the vehicle via an insulating pad 92. A plug 94 connected through cap 80 is used to couple circuit board 84 to sensor 12 and to provide power.

The sensor 12 operates as follows. The safety sensor 12 can be located, for example, in a fireproof wall or compartment of a vehicle, while the primary sensor 14 can be located in the compartment or in a crash zone. As shown in FIG. 2, the upper blades 50, 52 urge the sphere 34 so that the sphere contacts the wall 30. The sensor 12 is arranged so that the sphere 34 is biased in the direction of arrow A (FIG. 2) when the vehicle is decelerated. If this deceleration is greater than a predetermined threshold (threshold) (defined by the biasing forces of the blades 50, 52), this deceleration force overcomes the biasing force and the sphere 34 projects in the direction A along the passage 40. To do. First, the sphere 34 is the blade 5
It contacts the tip of 0,52. When the sphere moves in the direction A, it bends the blades 50, 52 in the same direction until they contact the curved portions 58, 60, as shown in FIG. Therefore, the electrical path is
0, and another electrical path is formed between the blades 46, 52. These electrical pathways can be used to generate electrical signals that are sent from the conductors of plug 94 to sensor 12, for example, as described above.

4-8 show a safety sensor according to another embodiment that is magnetically biased rather than mechanical. The safety sensor 100 has two parts, namely an elongated tubular part 104.
And a housing 102 consisting of a base 106. The base may be rounded at the corners 108 (FIG. 4). The housing 102 is made of plastic or a non-magnetic metal material. A holding member 110 made of the same material as the housing 102 is provided at one end of the base portion 106.

The interior of the housing portion 104 is divided by a wall 113 into two chambers 112, 114 arranged coaxially. The chamber 112 contains a permanent magnet 115. The chamber 114 defines a path of movement for the inertial member consisting of a sphere 116. The sphere is preferably formed of a magnetizable material, the surface of which is electrically conductive. The chamber 114 is a sphere 11.
It has a plurality of longitudinal ribs 118 that define six travel paths. The ribs are arranged to allow air to flow around the sphere 116 as it passes through the housing. Thereby, the movement of the sphere is not substantially weakened. The member 120 is the housing member 104.
It is provided around. As shown in FIG. 5, the member 12
The 0 extends only along a portion of the housing portion 104 and therefore does not overlap the housing portion 106. The member 120 is formed of a magnetizable material and is used to concentrate the magnetic field generated by the magnet 115 in the chamber 114. In this way the size of the magnet and thus of the sensor can be minimized. Regarding this member, US Application No. 418,1 filed on Oct. 6, 1989.
No. 47 for details. Member 120 is tab 12
2 holds it in the correct position with respect to the housing member 104.

Housing portion 106 is another chamber 12
4 is formed. Two contact blades 126, 128 are provided in this chamber 124. Blades 126, 12
8 is made of a flexible conductive material. Each blade has a linear member 130, 132 with a holding member 11
It is fixed at 0. As shown, the chamber 124 is the chamber 1
It communicates with 14. A cylindrical shoulder 134 is provided at the boundary of these two chambers. Blades 126 and 128
Has a shape such that it is normally urged to come into contact with the shoulder portion 134. Thus, these blades
Set in a manner similar to that described in US Application No. 417,914 filed October 6, 1989. A stopper 138 is supported on the cap 110 in the chamber 124. This stopper causes the sphere 116 to finish moving.

As shown in more detail in FIGS. 5, 6 and 8, the blades 126, 128 extend through the retaining member 110 and are connected at their outer ends 130, 132 to electrical wires 140, 142, respectively. These electric wires are arranged at right angles to the blades 126 and 128, for example.
The housing 102 further includes mounting legs 144 that extend parallel to the wires 140, 142. As shown in FIG. 8, these elements connect the sensor 100 to the printed circuit board 146.
Used to attach to. Preferably, the electric wire 14
0, 142 are connected to conductors (not shown) on the circuit board 146, while the legs 144 are used to support the sensor on the circuit board 146. The circuit board 146 is the expansion device 1
6 and other electronic components for controlling the airbag 18 are retained. Further, the primary (identification) sensor 14 may be attached to the circuit board 146.

In operation, the inertia member or sphere 1
The magnet 16 is normally urged by the magnet 115 so as to come into contact with the wall 113. The sphere 116 moves away from the wall 113 towards the stop 138 when the vehicle is involved in a collision. The sphere has contact blades 130, 132
When the tip of the blade is touched, an electric path is formed from one blade to the other blade through the sphere, which indicates that a collision has occurred. This action sends a signal to an identification sensor that determines whether the occupant restraint system should be deployed. In addition, it goes without saying that the present invention can be variously modified within the scope of the technical idea described in the claims.

[Brief description of drawings]

FIG. 1 is a block diagram of a restraint system according to the present invention.

FIG. 2 is a side view of an accelerometer according to the present invention.

FIG. 3 is a diagram showing a state where the sensor of FIG. 2 has closed contacts.

FIG. 4 is a top view of another embodiment of the present invention.

5 is a side view of the embodiment of FIG.

FIG. 6 is a bottom view of the embodiment of FIG.

FIG. 7 is a side view similar to FIG. 5, showing a state where the inertial mass moves in response to deceleration.

FIG. 8 is a partial side view of a sensor supported by a printed circuit board.

[Explanation of symbols]

 10 Occupant Restraint System 12 Safety Sensor 34 Sphere (Inertial Member) 40 Passage 46, 48 Lower Blade (Second Contact Means) 50, 52 Upper Blade (First Contact Means) 70 Rib

 ─────────────────────────────────────────────────── ———————————————————————————————————————————————— Inventor Allen Breed 41, Farber Hill Road, Booneton Township, NJ, USA (72) Inventor, Tojon Swaen, Morris Plains, NJ, Mountain Way 703 Address (72) Inventor Carl Tee Grosie, Westview, Morris Plains, NJ, USA 23154

Claims (15)

[Claims] 1. A housing having a first end and a housing portion located opposite the first end to form a passage, and disposed in the housing and substantially undamped. An inertia member sized to move through the passage and first and second contact means disposed in the housing, the first contact means being flexible, the inertia member being the first member. Urging toward the end, the inertial member passing through the passage substantially undamped in response to deceleration to bend the first contact means toward the second contact means. An accelerometer that detects changes in vehicle speed. 2. The accelerometer according to claim 1, wherein each of the first and second contact means has a pair of contact blades. 3. The one of the inertia member and the contact means is insulation-coated to prevent the formation of an electric path formed through the inertia member.
Accelerometer described in. 4. An airbag arranged in a vehicle, a control unit for selectively deploying the airbag in the vehicle to protect an occupant in the event of a collision, and a control unit connected to the control unit. The vehicle includes a primary sensor for detecting a change in speed of the vehicle and a safety sensor, the safety sensor being provided in the vehicle and having a housing forming a passage, and being axially arranged in the housing. A pair of contact blades, an inertia member arranged in the passage and having a size capable of passing through the passage without being damped, and a biasing means for biasing the inertia member to a predetermined position. An occupant restraint system for an automobile, characterized by having. 5. The occupant restraint system according to claim 4, wherein the biasing means comprises magnetic biasing means for biasing the inertial member. 6. The occupant restraint system according to claim 4, wherein the biasing means biases the inertial member to a first position away from the contact blade. 7. The occupant restraint system of claim 4, wherein the housing is positioned such that the inertial member is biased toward the contact blades when the vehicle is decelerated. 8. The urging means further comprises a conductive member for applying the magnetic force to the inertia member, and the conductive member is arranged outside the housing. Occupant restraint system. 9. The occupant restraint system of claim 8, wherein the inertia member is a sphere. 10. The occupant restraint system of claim 4, wherein the contact blade has an insulating coating that insulates itself from the inertial member. 11. A pair of first blades arranged in the passage of the inertial member is provided, and a pair of second blades is provided which is separated from the pair of first blades by the inertial member. The occupant restraint system according to claim 10, wherein two electric passages are formed through a pair of second blades. 12. The occupant restraint system according to claim 4, wherein the control unit comprises a printed circuit board, and the safety sensor comprises mounting means for mounting the safety sensor on the printed circuit board. 13. A housing having a pair of contacts, an inertia member arranged in the housing, a biasing means arranged in the housing, a printed circuit board, and the housing attached to the printed circuit board. Mounting means, the housing forming an undamped movement pattern of the inertial member with respect to speed changes, the biasing means biasing the inertial member to a first position along the movement passage, the inertial member Forming an electrical path between the pair of contacts away from the first position in response to the speed change. 14. The sensor according to claim 13, wherein the biasing means has a magnet, and the inertia member is made of a magnetic material. 15. The sensor of claim 14, wherein the contacts extend through the housing, the housing being attached to the printed circuit board.