WO1999003711A1

WO1999003711A1 - Weight responsive supplemental restraint computer system

Info

Publication number: WO1999003711A1
Application number: PCT/US1998/014184
Authority: WO
Inventors: Joseph A. Tabe
Original assignee: Tabe Joseph A
Priority date: 1997-07-14
Filing date: 1998-07-13
Publication date: 1999-01-28
Also published as: AU8388498A

Abstract

A supplemental passenger restraint system wherein the weight of an occupant (110) is accurately determined and used to generate an airbag deployment force sufficient to prevent injury from a col lision, but does not harm the passenger with the deployment itself. A load cell (15) is mounted between a passenger seat (10) and the vehicle floor (100) for sensing the weight of the occupant (110).

Description

WEIGHT RESPONSIVE SUPPLEMENTAL RESTRAINT COMPUTER SYSTEM

BACKGROUND OF THE INVENTION

1. FIELD OF THE INVENTION

The present invention relates generally to passenger vehicle supplemental restraint systems commonly known as air bags. More specifically, the present invention relates to a supplemental restraint system which is sensitive to a calculated passenger weight.

2. BACKGROUND OF THE INVENTION

The advantages of supplemental restraint systems, in passenger vehicles, in combination with the use of seat belts have been well appreciated. The use of air bags in modern vehicles is fast becoming an absolute standard.

Recently, however, a problem has arisen which presents both real and perceived hazards in the use of air bags. Air bags are primarily designed for the benefit of adult passengers. When children or infants are placed in the front passenger seat, deployment of an air bag could cause, and has caused, serious injury. Automobile manufacturers, realizing this hazard, have recommended that children and infants only ride in the rear passenger seats of automobiles.

According to the National Highway Transportation Safety Board, "smart" technology air bags should be in place by automakers starting with the 1999 motor vehicles. In short, "smart technology^" air bags adjust air bag deployment to accommodate the specific weight considerations of the passenger who would be affected by its deployment. The end result is that small passengers are not injured by the deployed air bag.

While air bags have been credited with saving thousands of lives, the tremendous force of air bag deployment has proven that injuries often result from these expensive measures to promote safety. Air bags have been blamed for the deaths of many children and adults in low-speed accidents that thev otherwise would have survived. Placing infants and small individuals in the front passenger seat of automobiles has led to some serious, but avoidable, tragedy. Unfortunately these accidents have had a secondary effect in that the public is beginning to perceive air bags as inherently dangerous and. therefore should be selectively disabled, if installed at all. In light of the statistics, air bags have provided a net life saving, thus the solution to the above problem should be less drastic than termination of same in order to prevent them from injuring younger passengers.

Inevitably, children will be placed in the front passenger seat of automobiles, whether this is due to ignorance of the hazards, or simply due to the necessity of fitting a number of passengers in a particular vehicle. Therefore, the solution lies in adapting the supplemental restraint system to adjust deployment force to compensate for the presence of smaller passengers. It should be noted that, while less likely, smaller adults also may be injured by the deployment of an air bag.

The most obvious solution to the problem, and one which the public seems to be demanding if air bags are to be used at all, is that the operator of the vehicle have the option of disabling the air bag. This solution has several problems. First, inevitably, the operator may forget to disable it when it should be. Second, the operator may forget to enable the system when desired for adult passengers. Finally, entirely disabling the system deprives children and smaller passengers of the benefits of air bags.

In order to avoid some of the above problems, prior art devices have incorporated measurement systems into the seats of some vehicles to gather information about the passenger and to operate the air bag in accordance with that information. These systems generally represent a simple "on" or "off selection. First, if a passenger is not located in the seat, or does not trigger certain secondary detectors, the restraint system is disabled. If the detector properly senses a passenger the air bag is simply "enabled". This is exemplified by United States Patent No. 4.806,713. issued February 21, 1989. to Krug et al. , which shows a seat-contact switch for generating ^ a "seat occupied"' signal when an individual is sensed atop a seat. The Krug et al. device does not have the abilitv to measure the mass of the seated individual. United States Patent No. 5,071,160, issued December 10. 1991. to White et al. provides the next iteration of this type of system. A weight sensor in the seat, in combination with movement detectors, determine if it is necessary to deploy an air bag. If an air bag is deployed, the weight sensor determines what level of protection is needed and a choice is made between deploying one or two canisters of propellant. First, the weight sensor is located in the seat itself, which inherently leads to inaccurate readings. Second, the level of response has only a handful of reaction levels, thus a passenger not corresponding to one of these levels may be injured due to improper correlation of deployment force used to inflate the air bag.

United States Patent No. 5,161,820, issued November 10, 1992. to Vollmer. describes a control unit for the intelligent triggering of the propellant charge for the air bag when a triggering event is detected. Vollmer^* s device provides a multiplicity of sensors located around a passenger seat so as to sense the presence or absence of a sitting, standing, or kneeling passenger. The Vollmer device is incapable of sensing varying masses of passengers and deploying the air bag with force corresponding to the specific passenger weight. Rather, the Vollmer seat and floor sensors ascertain whether a light-weight object, such as a suit case, is present or a relatively heavier human being.

None of the above inventions and patents, taken either singly or in combination, teaches or suggests the present invention.

SUMMARY OF THE INVENTION

The present invention is designed to deploy an air bag intelligently through the use of weight sensors. The applicant has recognized that there are two points of concern relative to air bag deployment, both centering around the concept that the force of air bag deployment can cause as much injury as an actual auto accident collision (without the protection of air bag). First, the passenger^'s weight must be determined accurately. Second, once an accurate measure of passenger weight has been ascertained, air bag deployment must be controlled to apply an amount of force appropriate to protecting the passenger.

The present invention provides controlled air bag deployment with regard to the mass of the passenger. A load cell underneath a passenger seat senses the weight of a passenger at regular intervals. The load cell accurately determines passenger weight, as opposed to seat sensors embedded within the seat cushion which provide a '"passenger present" signal.

Further, the present invention discloses a mechanism for providing controlled air bag deployment based on the mass of the passenger. In this regard, the mechanism variably controls the amount of gas in a combustion chamber which propels the air bag. The air bag can deploy with as little or as much force as is appropriate based upon the passenger^'s weight.

Accordingly, it is a principal object of the invention to provide a supplemental restraint system having an accurate weight sensor to determine the presence and weight of a passenger.

It is another object of the invention to provide a correlation between the weight of the passenger and the deployment characteristics of the air bag.

It is a further object of the invention to provide an air bag deployment system which is infinitely variable between an upper and lower threshold, to positively correlate the force of the air bag to the force of a moving passenger.

Still another object of the invention is to prevent the deployment of an air bag when no passenger is present.

Yet another object of the invention is to provide a mechanism to detect the imminence of a rear impact and to timely deploy an air bag in response thereto. It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.

These and other objects of the present invention readily will become apparent upon further review of the following specification and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is side view of a passenger in a vehicle using the supplemental restraint system of the present invention.

Fig. 2. is a block diagram of the primary components of the supplemental restraint system of the present invention.

Fig. 3. is a circuit diagram of the components of the present invention.

Similar reference characters denote corresponding features consistently throughout the attached drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Turning to Figs. 1 and 2, the preferred embodiment of the present invention is shown. The system generally includes the known standard configuration for a passenger's and driver's side frontal air bag. Each side is configured in the same manner, therefore only the passenger side air bag will be described.

The passenger seat (10) is mounted on a loadcell (15) which is embedded in the floor (100) of the vehicle. The loadcell (15) ascertains the weight of the passenger seat (10) and any occupants ( 1 10) therein. By mounting the loadcell (15) between the seat (10) and floor (100), rather than mounting it within the passenger seat (10), the present invention is more likely to obtain an accurate measurement of passenger weight, not being subject to faulty readings due to the nature and configuration of the cushioning (not shown) of the passenger seat (10) and passenger movement.

The loadcell (15) is constructed from machined steel having strain gauges (11) bonded inside.

When weight is applied to the passenger seat (10), the strain gauges (1 1) are strained in a corresponding amount. As the strain gauges are stressed, the effective resistance thereacross varies in an amount corresponding to the strain. Voltage induced across each strain gauge is divided so that a voltage signal is obtained that corresponds to the weight of the passenger (1 10).

The loadcell (15) serves an initial and secondary purpose. Initially, a baseline is developed in conjunction with the loadcell (15) representing the weight of only the passenger seat (10). Once the initial baseline is ascertained, during operation of the vehicle, if the baseline amount is not exceeded by a set amount, the air bag (1,2) is disabled, thereby preventing the air bag (1,2) from being used when a passenger (1 10) is not present. The loadcell (15) secondarily functions to accurately weigh a passenger (1 10) when the baseline representing the weight of the passenger seat (10) is exceeded. This information is then passed on to the automatic controller (25) which determines the proper force at which the air bag (1,2) should discharge based on the passenger weight.

Referring also to Fig. 3, in the controller, an electrical signal from the loadcell (15) is amplified by amplifier (20). shown on Fig. 2, and sent to the automatic controller (25). The automatic controller (25) discriminates between the passenger side and drivers side loadcells (15) to determine which air bag(s) (1,2) are to be enabled. The electrical signal is next sent to encoder (30) which is an analog-to-digital converter. The electrical signal, up until such point, has been an analog voltage signal representative of the weight of the passenger (1 10). At the encoder (30), the electrical signal is converted into a digital signal and transferred to meter decoder (35). The meter decoder (35) analyzes the digital input and coverts it into a weight value corresponding to the weight of the passenger, which is then stored in memory (32).

A transient voltage suppressor (200) is located between the meter decoder (35) and the memory (32). Recognizing that electronic equipment characteristically suffers from transient voltage spikes, and that such spikes would cause abnormal readings for the memory (32), the applicant has positioned voltage suppressor (200) to filter out transient spike phenomenon. Thus, the accurate weight value is ensured.

The weight value is then passed on to an accelerometer (40). The accelerometer (40) converts the weight value corresponding to the passenger (110) into an acceleration value corresponding to the proper amount of acceleration at which the air bag ( 1 ,2), as shown in Fig. 2, would have to be deployed to protect the passenger in the event of a collision. Because the readings from the loadcell (15) are dynamic, a new acceleration value is calculated each time a new signal is output from the loadcell (15). The acceleration value is used by the accelerometer (40) to apply a proportional amount of force against crystals (45), shown in Fig. 3, in the accelerometer (40) to generate a corresponding amount of electrical energy therefrom, such as might occur with a piezoelectric solid. Accordingly, the voltage developed across the crystals (45) is proportional to the amount of acceleration required to deploy the air bag (1,2) properly. This is accomplished by displacing a mass (52), shown on Fig. 3, inside the accelerometer (40). In short, this amounts to having the force exerted by the mass (52) on the crystals (45) proportional to the force exerted by the passenger ( 110) on the passenger seat (10).

The resultant voltage developed by the crystals (45) is correlated to the necessary force required to protect the passenger (1 10). The voltage is used to generate a current to ignite gases (not shown) in a canister (60). shown on Fig. 3. The current and the amount of gas (not shown) employed are controlled to provide the desired expansion rate of the air bag (1,2). Thus, there is an allowance for infinite variation between an upper and lower threshold for deployment force of the air bag (1,2). Therefore, regardless of the weight of the passenger (110), the proper amount of gas (not shown) is ignited to propel the air bag (1,2) with just enough force to cushion the passenger (1 10), without injuring the passenger (1 10).

The controlled release of gas (not shown) from the canister (60) is accomplished by a sliding outlet port (not shown) which is opened a specific amount as a result of the voltage generated by the accelerometer (40). As a result, the force of the deploying air bag ( 1 ,2) should correctly match the force of the passenger (1 10) in the passenger seat (10).

In a front impact of about 13.2 MPH, collision sensor (75) is activated. The 13.2 MPH speed represents the threshold speed at which the efficacy of any air bag system should usually become activated. At collisions of below 13.2 MPH, air bags systems tend to become less effective and expensive to deploy. While the present invention can function even if a front impact is of extremely low speed, the preferred embodiment of the present invention would not engage until a front impact of 13.2 MPH is achieved. At that time the data stored in memory (32) is used as the proper force calibration and the air bag (1,2) is deployed at the proper level. The weight of the passenger (110) is correlated into an expected impact force and the desired amount of propellant is ignited to provide a cushion which balances this force, but does not overpower the passenger (1 10) and force the passenger ( 1 10) backwards into the passenger seat (10) at such a rate as to cause injury.

In order to employ the present invention in the event of a rear-end collision, an enhanced embodiment of the present invention includes a radar unit (70) which is used to sense the imminence of a rear impact. This data is received by radar receiver (71) and fed into the automatic controller (25) which will immediately cause the deployment the air bag (1,2) with the proper force as discussed above. Radar unit (70) and radar receiver (71) are not shown in Figure 3 (which illustrates the primary embodiment of the present invention). In one embodiment, the air bag (1,2) has two layers (not shown) to further minimize the impact of deployment. An internal layer (not shown) is the base of the air bag (1,2) itself, which is deployed according to the system described above. An external layer (not shown) is a cushion layer characterized by being extremely foamy. There is a gap (not shown) between the two layers. As before, the weight of the passenger (110) is correlated into an expected impact force and the desired amount of propellant is ignited to provide a cushion which balances this force, but does not overpower the passenger (110) and force the passenger (110) backwards into the passenger seat (10) at such a rate as to cause injury. The greater the amount of propellant. the smaller the distance between the two air bag layers upon deployment. Thus, the two layer air bag (1 ,2) serves to further prevent air bag deployment injuries.

Another embodiment of the present invention includes several conventional sensors (not shown) positioned on the seat belt (not shown) of the passenger (1 10) and on the air bag itself. The sensors (not shown) communicate so that the deployment direction of the air bag (1,2) can be minimized away from the head of the passenger (110), so as to further prevent injury.

It is to be understood that the present invention is not limited to the sole embodiment described above, but encompasses any and all embodiments within the scope of the following claims.

Claims

CLAIMSI claim:

1. A supplemental restraint system comprising: a loadcell, interposed between a floor and a seat of a vehicle, generating a weight signal corresponding to a weight of an occupant on the seat; a meter decoder, responsive to said weight signal, generating a mass value; an accelerometer, responsive to said mass value, generating electrical energy corresponding to said mass value; and a gas canister, defining a combustion chamber, responsive to said accelerometer, releasing a gas into said combustion chamber at a rate corresponding to said mass value, said electrical energy igniting said gas and deploying an air bag at a rate corresponding to said mass value.

2. The supplemental restraint system according to claim 1. including an amplifier electrically interposed between said loadcell and said meter decoder.

3. The supplemental restraint system according to claim 1. including a memory, electrically connected to said meter decoder, storing said mass value.

4. The supplemental restraint system according to claim 1. including a digital-to-analog converter electrically interposed between said loadcell and said meter decoder.

5. The supplemental restraint system according to claim 1, including a transient voltage suppressor electrically interposed between said meter decoder and said memory.

6. The supplemental restraint system according to claim 1, further comprising: a second loadcell. interposed between the floor and a second seat of the vehicle, generating a second weight signal corresponding to a second weight of a second occupant on the second seat; and a controller electrically connected to said loadcell and said second loadcell, distinguishing between said weight signal and said second weight signal; wherein said controller enables the air bag responsive to said weight signal and said controller enables a second air bag responsive to said second weight signal.

7. The supplemental restraint system of claim 1, said loadcell being constructed from steel.

8. The supplemental restraint system of claim 1, said loadcell including a strain gauge mounted thereon.

9. The supplemental restraint system according to claim 1. said accelerometer including a mass selectively engaged with a crystal with a force corresponding to said mass value, said crystal generating a voltage across a surface thereof corresponding to said mass value.

10. The supplemental restraint system according to claim 1 , including a radar unit, responsive to rear end collision, triggering deployment of said air bag.

1 1. The supplemental restraint system according to claim 1. including a sliding outlet port, controlled by said accelerometer, and releasing gas into said combustion chamber at a rate corresponding to said mass value.

12. The supplemental restraint system according to claim 1. including an impact collision sensor adapted to initiate a response of said supplemental restraint system.

13. The supplemental restraint system according to claim 1. including a sensor mounted on a seatbelt provided for the seat and a sensor mounted on the air bag, cooperatively influencing deployment direction of the air bag.

14. The supplemental restraint system according to claim 1 , wherein the air bag comprises: an internal layer; and an external layer, having extremely foamy characteristics, mounted on said internal layer, defining a gap therebetween.

15. A supplemental restraint system comprising: an air bag; means for determining a mass of a passenger seated in a seat of a vehicle; and means for controlling a force exerted by said air bag upon expansion so that said force is proportional to said mass of said passenger; wherein said means for controlling said force of said air bag is infinitely variable between an upper and a lower threshold.

16. The supplemental restraint system according to claim 15, said means for determining said mass of said passenger being adapted to measure a weight of the seat and said passenger, said weight of said seat defining a threshold value: and said supplemental restraint system including means for analyzing said threshold value so that said air bag is deployed only when said threshold value is exceeded.

17. A supplemental restraint system comprising: at least one loadcell. interposed between a floor and at least one seat of a vehicle, generating at least one weight signal corresponding to at least one weight of at least one occupant on at least one seat; at least one meter decoder, responsive to at least one weight signal, generating at least one mass value: at least one accelerometer, responsive to said at least one mass value, generating electrical energy corresponding to said at least one mass value; and at least one gas canister, defining at least one combustion chamber, responsive to said at least one accelerometer, releasing at least one gas into said at least one combustion chamber per at least one rate corresponding to said at least one mass value, said electrical energy igniting said at least one gas and deploying at least one air bag at a rate corresponding to said at least one mass value.

18. The supplemental restraint system according to claim 17, further comprising: a controller electrically connected to said at least one loadcell, distinguishing between said at least one weight signal; wherein said controller enables each member of the group said at least one air bag to be particularly responsive to said at least one weight signal.

19. A supplemental restraint system comprising: at least one air bag; means for determining at least one mass of at least one passenger in at least one seat of a vehicle; and means for controlling at least one force exerted by said at least one air bag upon expansion so that said at least one force is proportional to said at least one mass of said at least one passenger; wherein said means for controlling said at least one force of said at least one air bag is infinitely variable between an upper and a lower threshold.

20. The supplemental restraint system according to claim 19. said means for determining said at least one mass of said at least one passenger being adapted to measure at least one weight of said at least one seat and said at least one passenger, said at least one weight of said at least one seat defining at least one threshold value; and said supplemental restraint system including means for analyzing said at least one threshold value so that said at least one air bag is deployed only when said at least one threshold value is exceeded.