Measuring and testing – Fluid pressure gauge – Combined
Reexamination Certificate
2003-05-27
2004-11-16
Oen, William (Department: 2855)
Measuring and testing
Fluid pressure gauge
Combined
Reexamination Certificate
active
06817248
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a human lumbar model structure for simulating a pressure applied to nucleus pulposus in a human lumbar and a method for fabricating the structure.
In order to estimate and evaluate a ride vibration comfort which would be felt by a human being (an occupant, a driver, a passenger, etc.) on a vehicle such as a motor vehicle, bulldozer, a train, a vessel, and a spacecraft travelling with vibration, variation in speed, and/or change of acceleration, sensory tests have only been used. However, the test results widely fluctuate among individuals. Thus, no basis for objective, persuasive, or quantitative evaluation of vehicles in the ride vibration comfort has been established yet.
Long-distance or long-time drivers often suffer from herniation of a lumbar intervertebral disk. According to one of the most convincing theories accepted by many orthopedists, the occurrence and the aggravation of the above-mentioned hernia are correlated with ride vibration discomfort when travelling in motor vehicles.
The lumbar region of the vertebral column of a human body comprises five vertebrae, that is, 1st lumbar vertebra, 2nd lumbar vertebra, 3rd lumbar vertebra, 4h lumbar vertebra, and 5th lumbar vertebra arranged in the order from upside to down side. There is the lumbar intervertebral disk between each two adjacent lumbar vertebrae. The vertebral column has the nucleus pulposus therein. The herniation readily occurs at the lumbar intervertebral disk between 4th and 5th lumbar vertebrae in comparison with the other lumbar intervertebral disks.
In order to make it possible to objectively and quantitatively evaluate ride vibration comfort which is the cause of suffering from herniation of the lumbar intervertebral disk, U.S. Pat. No. 6,311,562 (B1), which was issued on Nov. 6, 2001 to the same inventor of the present invention, discloses a human lumbar model structure for simulating pressure applied to nucleus pulposus in the lumbar spine of a human body.
The present inventor made a sample of the human lumbar model structure according to the embodiment of
FIG. 6
in the US patent and subjected to tests. The sample structure will briefly be described with reference to FIG.
1
.
The sample of the human lumbar model structure shown in
FIG. 1
comprises a cylindrical lumbar assembly and an abdominal/back muscle member. The,lumbar assembly comprises an upper body member
17
, an upper lumbar member
11
corresponding to a lumbar vertebra such as the fourth lumbar vertebra, an annulus fibrosus member
13
corresponding to the nucleus puplosus, nucleus pulposus agent or liquid
16
in the annulus fibrosus member
13
, a lower lumbar member
14
corresponding to an adjacent lumbar vertebra such as the fifth lumbar vertebra, and a lower body member
18
. These members are formed in a cylindrical shape, coaxially arranged around a common center axis and are vertically superposed from top to bottom in this order.
The abdominal/back muscle member shown at
19
is made of an elastic material and has a hollow cylindrical shape. The abdominal/back muscle member
19
surrounds and tightens the lumbar assembly over at least a center area of a narrowed portion thereof extending from the midlevel of the upper body member
17
to the midlevel of the lower body member
18
. In detail, the upper body member
17
comprises an upper portion
171
and a narrowed portion
172
as its lower portion with a reduced diameter and has a shoulder
173
on its outer surface at a bound between the narrowed lower portion
172
and the upper portion
171
. Similarly, the lower body member
18
comprises a lower portion
181
and a narrowed portion
182
as its upper portion with a reduced diameter and ahs a shoulder
183
on its outer surface at a bound between narrowed upper portion
182
and the lower portion
181
. When the abdominal/back muscle member
19
is attached to the lumbar assembly, it tightly surrounds the narrowed portions
172
and
182
and has an inner diameter equal to the diameter of the narrowed portions
172
and
182
but has an outer diameter larger than an outer diameter of the upper portion
171
of the upper body member
17
and the lower portion
181
of the lower body member
18
. Thus, the shoulders
173
and
183
serve as stoppers against axial or radial movement of the abdominal/back muscle member
19
.
The upper lumbar member
11
comprises an upper element
111
, which is formed in a circular columnar block and tightly fitted into a bottom surface of the upper body member
17
, and a lower element
112
, which is a circular disk shape and threaded into a bottom surface of the upper element
111
. And the lower lumbar member
14
comprises an upper element
141
in a ring form and a lower element
142
in a cylindrical form with an upper dosed end. The upper element
141
is threaded onto the upper outer surface of the upper lower element
142
. The lower element
142
is tightly fitted into an upper surface of the lower body member
18
, and is provided with a pressure sensor
21
as a pressure transducer therein on a common center axis position. A signal cable
23
from the pressure sensor
21
is lead out through a vertical guide hole
22
formed in the lower body member
18
. The annulus fibrosus member
13
is made of a full hard and elastic material and has a flexible structure with thickish and annular form. The annulus fibrosus member
13
is disposed between the lower element
112
of the upper lumbar member and the lower element
142
of the lower lumbar member and tightly fitted at opposite ends to the both lower elements
112
and
142
. The annulus fibrosus member
13
is disposed in the ring-shape upper element
141
of the lower lumbar member
14
. By this structure, an inner cavity is formed in the annulus fibrosus member
13
and is filled with the nucleus pulposus liquid
16
which is liquid as an artificial nucleus pulposus therein.
A loading member modeling the upper half of a human body is arranged on the top surface of the human lumbar model structure composed by fabricating above-mentioned. The ride vibration comfort or discomfort is evaluated by recording results of detecting instantly and continuously changes of the output voltage of the pressure sensor
21
when the human body fluctuates. For this purpose, the completed human lumbar model structure was subjected to a static loading test in which data are recorded about changes of pressure obtained from the nucleus pulposus member
16
by the increase and the decrease of the vertical loading onto the model structure.
However, as results of the static loading experiment, as shown in
FIG. 2
, we have found out a hysteresis phenomenon and non-linearity between pressure values obtained for loading up gradually and for loading down gradually from the value loaded once. This means that pressure fluctuation characteristic measured is not constant but unstable at different tests. Further, the same pressure value cannot be obtained for the re-assembling model after the model structure was disassembled. This means that the results of the measurements are not constant but unstable at every model structures assembled or reassembled.
Accordingly, we had various experiments so as to search reasons that cause the problems such as the hysteresis phenomenon, non-linearity and unstability. As the result, we found out the followings. When a vertical loading is applied to the human lumbar model structure, the abdominal/back muscle member
19
is distorted so that upper edge and the lower edge of the muscle member
19
go over the shoulders
173
and
183
to move onto the upper portion
171
of the upper body member
17
and the lower potion
181
of the lower body member
18
. The edge going-over phenomenon is one of reasons causing the problems, the present inventor considered. There is difference in contact forces with the upper body member
17
and the lower body member
18
and also in the internal stresses between portions of the muscle member
19
remaining on the upper and lower
Collard & Roe P.C.
Oen William
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