Measuring and testing – Fluid pressure gauge – Diaphragm
Patent
1998-01-20
1999-07-13
Oen, William
Measuring and testing
Fluid pressure gauge
Diaphragm
G01L 702, G01L 710
Patent
active
059229667
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to contact pressure measurement concerning soft materials such as external pressure applied to a human body in garments such as clothes, on a chair, in bedclothes, on a bed, and the like; and a measuring method in which a bag packed with air is held between contacts, the pressure of the air is measured over time, and thus measured value may be calibrated.
BACKGROUND ART
Conventionally, in the contact pressure measurement for soft materials, there have been no measuring instruments which are accurate and have a reproducibility. This is because the state and phenomenon of soft surfaces at the time of contact cannot be comprehended, for example. Also, calibration method for confirming their accuracy has not actually been established yet, thus making it impossible to judge whether each measuring instrument is good or bad.
For example, since strain gauge sensor system is a flat solid sensor, it has detected a bending stress even when it is simply attached to the surface of a site in a curved surface of a human body, and has yielded errors due to surface movement and shifting therebetween when they come into contact with each other and due to hindrance to each other upon expansion and compression. On the other hand, electric resistance system, which measures changes in electric resistance upon compression of an electrically conductive material, is disadvantageous in that its material is uneven, restoration after compression is slow, and reaction, i.e., resolution, upon strong compression is rough. There have been cases where this system is used with units indicated for these characteristics.
In liquid-pressure equilibration system, which is likely to be considered similar to the present invention, a bag in a pressure-receiving section is packed with a liquid. Here, zero correction is necessary for a pressure sensor, which is connected thereto via a tube, as well as its altitude. If their relative height with respect to each other changes after the correction, an error will occur. Also, it is unsuitable for dynamic measurement. It is because load generated upon acceleration yields an error with respect to the weight of the packed liquid.
Even in the case of a pressure-receiving sensor in which a bag is packed with air as with the present invention, when the bag uses an elastic material, the area of the surface to be measured always changes according to a contact strength, thus failing to achieve comparative measurement. In addition, commonly among the above-mentioned measurement systems, there is a pressure-receiving method in which the pressure-receiving section is formed like interconnected sheets or lattices so as to cover the contact surface. In this case, the soft surface may be restrained from changing its curvature or expanding and compressing itself, thereby yielding a measured value different from the actual contact state.
DISCLOSURE OF THE INVENTION
The present invention can accurately measure contract pressure of a soft surface and perform calibration for confirming the reproducibility and accuracy of thus measured value.
A bag made of a thin, soft, and less elastic material is packed with air; and is disposed between contacts, while being lead to the outside of the contacts via a tube, whereby a contact force can be measured as a pressure when a pressure difference between the air and a pressure within the bag is measured. The accuracy of the value measured under this measurement condition is confirmed by water pressure mmH.sub.2 O as the bag is horizontally sank into water. Also, as the water temperature is changed, thermal influence can be observed.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an overall configurational view showing a measuring method of the present invention;
FIG. 2 is a sectional view showing pressure calibration by water pressure;
FIG. 3 is a sectional view for observing a correlation between pressure and temperature; and
FIG. 4 is a graph showing the correlation between pressure and temperature measured in FIG. 3.
BEST MOD
REFERENCES:
patent: 4052903 (1977-10-01), Thodarson
patent: 5260692 (1993-11-01), Claen
J.P.O. Patent Bulletin 64P1744 Abstract & Drawing of 6-50828(A) Published Feb. 25 1994.
J.P.O. Patent Bulletin 163 P1333 Abstract & Drawing of 3-29633(A) Published Dec. 27, 1991.
J.P.O. Patent Bulletin 30P1203 Abstract & Drawing of 3-46533(A) Published Feb. 27 1991.
AMI Co. Ltd
Oen William
Usher Robert W. J.
LandOfFree
Air-pack type contact pressure measuring method does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Air-pack type contact pressure measuring method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Air-pack type contact pressure measuring method will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2277367