Weighing scales – Structural installation – Furniture or room fixture
Reexamination Certificate
2000-03-09
2001-11-27
Gibson, Randy W. (Department: 2859)
Weighing scales
Structural installation
Furniture or room fixture
C177S256000, C177SDIG009, C180S273000, C280S735000
Reexamination Certificate
active
06323444
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus for measuring the weight of a vehicle seat including the weight of a passenger sitting thereon and, more particularly, to a seat weight measuring apparatus which is improved to have higher precision in measuring the weight of a passenger sitting on a vehicle seat. Further, it relates to a seat weight measuring apparatus capable of detecting the center of gravity of a passenger with a smaller number of load cells.
2. Description of the Related Art
Automobiles are equipped with seat belts and airbags to secure safety for passengers. In recent years, there is a trend for controlling the operation of such safety devices according to the weight (body weight) and/or posture of a passenger for improved performance of seat belts and airbags. For example, the amount of gas to be introduced into the airbag, an airbag inflating speed, or a pre-tension of the seat belt may be adjusted according to the weight and/or posture of a passenger. For that purpose, some means are needed for measuring the weight of the passenger sitting on the seat. In addition, for estimating the posture of the passenger, the position of the center of gravity of the passenger on the seat can be referred.
An example of such means includes a proposal (Japanese Patent Applications No. 9-156666, No. 10-121627, and the like filed by the applicant of this invention) which involves arranging load sensors (load cells) at four corners of the seat under seat rails and summing vertical loads acting on the load cells to know the weight and the center of gravity of the passenger. According to the proposed method, the position of the center of gravity of the passenger on the seat can be also obtained.
However, since such seat weight measuring apparatuses are installed in general motor vehicles, these must be manufactured at low cost. Further, these must be easily wired and easily assembled. It is necessary for accurate measuring to exclude other load than the weight of a seat and the weight of a passenger (or an object) on the seat.
SUMMARY OF THE INVENTION
An object of the present invention which is made in view of the above-described problems is to provide a seat weight measuring apparatus capable of decreasing manufacturing cost and assembly cost and capable of weight measurement with higher precision.
In order to solve the problems described above, an a seat weight measuring apparatus of a first aspect of the present invention is an apparatus for measuring the seat weight of a vehicle seat including the weight of a passenger sitting thereon, comprising: a load cell having a plurality of sensors, each of which converts at least a part of the seat weight into an electrical signal; connecting mechanisms arranged at four locations, front and rear on left and right sides, which bear the seat weight, for connecting the vehicle seat and the seat fixing portions of a vehicle body; and transmitting mechanisms for transmitting the action of the seat weight born by the connecting mechanisms to the load sensors, wherein the one load cell includes a plurality of the sensors, each of which the action is transmitted from each transmitting mechanism.
The load sensor for measuring loads on front and rear locations on left and right sides of the seat are arranged as compact as possible, thereby reducing the number of load cells. Therefore, the manufacturing cost and also the assembly/wiring cost are reduced. Even with the reduced number of the load cells, the loads on the four locations, front and rear on left and right sides, can be measured, thereby detecting the center of gravity of the passenger.
It is preferable, in the seat weight measuring apparatus of the present invention, that the transmitting mechanism selectively transmits vertical loads on the connecting mechanisms to the load sensors by canceling lateral loads.
The transmitting mechanism transmits as little lateral loads as possible from the connecting mechanism to the load sensor wherein the lateral loads may cause error of the load sensors. Therefore, the weight of the passenger can be measured with higher precision.
It should be noted that the intention of the seat weight measuring apparatus as described in this specification is basically to measure the weight of a passenger sitting on a vehicle seat. Accordingly, an apparatus for measuring only the weight of a passenger by canceling the weight of a vehicle seat itself is also contained in the range of the seat weight measuring apparatus disclosed by this specification.
In the seat weight measuring apparatus according to one concrete aspect of the present invention, the connecting mechanisms and/or the transmitting mechanisms include arms pivotally supported by pivot shafts extending perpendicular to the vertical direction so that the actions according to the pivotal movements of the arms are transmitted to the load sensors. It is characterized in that the one load cell includes a plurality of the sensors, each of which the action is transmitted from each arm.
Because of the functions of the pivot shafts and the arms, most of lateral load exerted on the connecting mechanisms is born by the pivot shafts, thereby preventing the transmission of the lateral load from the arms to the load sensors. This enables the weight of the passenger to be measured more precisely.
It is preferable that the seat weight measuring apparatus of this aspect further comprises burdening members, each of which is pivotally connected to each arm, for bearing at least a part of the seat weight. This makes the connection of the arms and the seat smooth.
It is preferable, in the seat weight measuring apparatus of this aspect, that the sensor and the arms are connected to each other by one horizontal shaft so as to allow the pivotal movement in the vertical direction. Even when a lateral positional variation arises on the arm, the variation is absorbed at the action point so as not to be transmitted to the load sensor.
A seat weight measuring apparatus of a second aspect of the present invention is an apparatus for measuring the seat weight of a vehicle seat including the weight of a passenger sitting thereon, comprising: a load cell having a plurality of sensors, each of which converts at least a part of the seat weight into an electrical signal; connecting mechanisms arranged at four locations, front and rear on left and right sides, which bear the seat weight, for connecting the vehicle seat to the seat fixing portions of a vehicle body; and transmitting mechanisms for transmitting the action of the seat weight born by the connecting mechanisms to the load sensors, wherein the transmitting mechanism has a designed flexible configuration at at least one controlled position thereof. It should be noted that the designed flexible configuration means a portion, of which the shape and/or material are intentionally selected or determined to be easily deflected.
The presence he flexible configuration permits wide allowance limits of error in the parts and their assembly. It also exhibits work and effect of protecting the sensor by limiting the propagation of shock wave.
It is preferable, in the seat weight measuring apparatus of the present invention, that certain play exists between the arm and the load cell. This play exhibits the same work and effect as the flexible configuration as mentioned above. It also exhibits work and effect of absorbing horizontal dislocation due to the pivotal movement of the arm.
It is preferable that the seat weight measuring apparatus of the present invention further comprises burdening members, each of which is pivotally connected to each arm, for bearing at least a part of the seat weight, wherein a horizontal distance (span) between the pivot shaft of the arm and a point where the burdening member is connected to the arm: a horizontal distance between the pivot of the arm and a point where the arm acts on the load sensor is in a range from 1:3 to 1:10.
In this range, loads directly applied to the load cells can be reduced with
Foley & Lardner
Gibson Randy W.
Takata Corporation
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