Note: Descriptions are shown in the official language in which they were submitted.
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AL~VI'ltCy ,LJt)Cket No. 486 P 116 PATENT
PORTABLE )<NCLINOMETER
DESCRIPTION
CROSS-REFERENCE TO RELATED APFLICATIONS
[OOOT] 'lltis application claims priority to Chinese Application No.
200320072771.$, filed
on June 17, 2005, the entire disclosure of which is incorporated herein by
reference.
TEC,fEVICAL 1=tELD
[0002] The present invention relates to an inclinornetar, and particularly to
a partabla
electronic inclinometer by utilizing the measurement ptinciple of hot air mass
convection.
BACKCI1ZOUND OF THE INVENTION
[0003] It is a common practice to measure the tilting angle of a plane surface
in building
engineering, house decoration and other constructional engineering. A simple
inclinometer
could be a calibrated bubble or a solid-petndulum with a poi»ter and a dial.
However, the
measure precision with them is not sufFcient and the measurement error is
rather high
resulting from reading by an operator himself according to the indlcadng of
the abova-
mentioned devices.
(0004] More precise electronic inclinometers in the art normally are
electrolytic type
inclinometer and solid-pendulum typo inclinometer. Based on the principle that
the surface of
electrolyte always keeps level, an electrolytic type inclinometer measures the
depth variations
of its electrodes immerged in the electrolyte to obtain the tilting angle. A
solid-pendulum
type inclinometer, based On the principle that the pendulum will always keep
plurxtb under
gravitation, converts the offset of the pendulum from a reference position
into an electrical
signal to calculaoe the tilting angle. However, these electronic inclinometers
have rather
complicated structures, and poor anti-impact and anti-vibration performance,
and that' are
easily damaged.
[0005 'The present invention is provided to solve the problems discussed above
and other
problems, and to provide advantages and aspects not provided by prior
inclinometers of this
type. A full discussion of the features and advantages of the present
invention is deferred to
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Attorney bocket ~to. 4386 P 116
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the following detailed description, which proceeds with reference to the
accompanying r
l
drawings. ~'
SUMMARY OF 'THE INVENTIQN
[0006] An object of the invention is to provide a portable electronic
ineliaometer with
simplified structure, improved anti-impact and anti-Vibration properties, and
with high
precision.
[0007] In order to fulfill the above object, as inclinometer provided by this
invention
comprises a casing, a measurement display unit and a set of operational
buttons provided do
the casing, a measuring circuit installed inside the casing and a power supply
supplying
power to the display unit and the measuring circuit. The casing comprises a
reference
measuring surface. The measuring circuit comprises a tilting angle sensing
unit which
includes a gets-filled sealed chamber. Inside the chamber, there is a heating
element and a set
of temperature sensing tlements which comprises at least one pair of
temperature sensing
elements symrnottlcally arranged about the hcadng element.
[0008] During measuring, the gas inside the sealed chamber is heated by the
heating
element with a result that a hot gas mesa which can be moved freely is the
chamber is
created. While the tilting angle sensing unit is placed. horizontally, the
temperature
distribution of the hot gas mass is centrally symmetric about the heating
element. In this case,
the temperatures detected by alI the temperature sensing elements are
identical and therei'orc
their output electronic signals are on a same level. 0a the other hand, when
the dldng angle
sensing unit is fitted, owing to the gravitation, free convection will occur
with the hot gas
mass, which will result in a variation o! the temperature distribution of the
hot gab mass, so
that there wilt be a difference between the output electronic signals from
each pair of
temperature sensing elements. The diPterenco is propordonal to the tilting
degree of the tilting
angle sensing unit and therefore, based on the diffcxence, the tilting angle
can be calculated.
By utilizing the freely conveetable hot gas mass as a gravity block, the
structure of the
inclinometer can be simplified with greatly improved and-impact and and-
vibration
properties.
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Attorney Docket No. 4386 P a 16
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[0009] According to the present invention, the tilting angle sensing unit of
the measuring
circuit of the inclinometer has a lust axis extending across the heating
element. A first pair ofl
temperature sensing elements located symmetric about the heating element is
disposed along ;
the first axis . The first axis is parallel to the reference measuring surface
of the casing, so I
that the tiling angle of the first axis will be the tilting angle of the
reference measuring
surface.
[0010] 'r'he tilting angle sensing unit of the measuring circuit of the
inclinometer
according to the present invention may further have a second axis extending
across the
heating element and perpendicular to the first axis. A second pair of
temperature sensing
elements which are located symmetric about the heating element is disposed
along the seeon~
axis. The second axis is perpendicular to the reference measuring surface of
the casing.
Combining the measurements based on both ~e first axis and the second axis,
the actor in the'
temperature sensing part resulting from temperature variation can be partially
decreased and
the precision of measurement can be further improved.
(0011] Other features and advantages of the invention will be apparent from
the
following specification taken in conjunction with the following drawings.
HIUEF DESCRIPTION OF THir DRAWiTTGS
[OO1Z] To understand the present invention, it will now ba described by way of
exempla,
with mferenca to the accomipanying drawings in which:
[0013] IPtCi. 1 is a parapacdve view of an inclinometeac according to a
prafanad
embodiment of the preset invention;
[0014] FIQ. 2a is a schematic diagram of a tilting angle sensing unit in a
measuring
circuit of the inclinometer according to the preferred embodiment of the
present invention;
[OOis] FIC3. 2b is a schematic diagram of the tilting angle sensing unit in
Figure 2a during
a measuring process;
[0016] FIG. 3a is a schematic diagram of a tilting angle sensing unit in a
measuring
circuit of an inclinometer according to another preferred embodiment of the
present
invention; and,
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Attorney Docket No. 4386 P 116
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[0017] FIG. 3b is a schematic diagram of the tilting angle sensing unit in
Figure 3a during',
a measuring process.
DETAILED DESCRIPTION
[OOIBj While this invention is susceptible of embodiments in many different
forms, thet'e
is shown in the drawings and will herein be described in detail preferred
embodiments of the
invention with the understanding that the present diseiosurc is to be
considered as as
exemplification of the principles of the invention and is not intended to
limit the broad aspect
of the invention to the embodinnenta illustrated.
[0019] figure 1 illuminates an inclinometer 1 according to a preferred
embodiment of the
present invention. The inclinometer 1 comprises a casing I 1, a display unit
12 and a set of
buttons on the casing 11, and a power supply (not shown in Figure 1) and a
measuring circuit
(not shown in Figure I) bath of which era installed inside the casing 11. The
set aP buttons
comprises a power button 14. Obviously, other buttons oar be provided
according to
requirements of the functions. For example, a storing button 16 can be added
to store the last
measurement data. The inclinometer 1 bas a reference measuring surface. It is
preferred to
predetemnine a bottom surface 18 of the casing 1 l as the reference measuring
surface. 'Che
displayed measurement data on the display unit 12 is the tilting angle of the
reference
measuring surface 18. During measuring, it is necessary to abut the reference
measuring
surface 18 against a surface to be measured. ?hose skilird in the art will
understand that other
appropriate portions of the casing can also be used as the reference measuring
surface.
[0020] Figure 2a is a principle schematic diagram of a measuring circuit of
the
inclinometer 1 according to the preferred embodiment of the present invention.
The
measuring circuit comprises a tilting $ngle sensing unit 20 ant! a signal
processing unit (not
shown). The tilting angle sensing unit 20 eamprisos a gas-filled sealed
chamber ZO1. Inside
the sealed chamber 201, a heating element 202 and a pair of temperature
sensing elements
203 and 204 are contained. The gas filled in the sealed chamber 20I may be air
or other type
of appropriate gases. The heating element 202 is located in the central part
of the sealed
ehambar 201. The temperature sensing elements 203 and 204 are located
symmetrically about
the heating element 202. The tilting angle sensing unit 20 has an axis ~C
extending across the
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Attorney Docket No. 4386 P 116
heating element 202 and another axis Y which is also extending across the
heating element
202 and orthogonal to the axis X. The temperature sensing elements 203 and 204
are both
disposed along the axis X, arid their output cerminals are separately
connected to the signal
processing unit, which, in turn, will prrx:ess the output signals from tho
temperature sensing
elements 203 and 204 and calculate the tilting angle of the axis X.
[Op2I] While the inclinometer 1 is in operation, the heating element 202 will
ba used to
heat the gas in the sealed chamber 201 to create a hot gas mass. If the axis
~t is is horizontal
direction, the temparattvre distribution of the hot gas mass is symmetric
about the axis Y, the
temperature values detected by the temperature sensing elements 203 and 204
are thus
identical. And therefore their outpat electronic signals is identical too.
knee the axis X is
tllted, due to the gravitation, free convection will occur with the hot gas
mass, which will
result in an asymmetric tesmperature disirlbution about the axis Y, the
tennperature values
detected by the temperature sensing ctemcnts 203 and 204 Is thus different
from each other,
and therefore, there is a differonce between tho two output electronic
signals. The diPPerenca
is a function of the tilting angle of the axis X, which can be expressed as: x
r g sin a, wherein
x is the difference between the output electrtmic signal from the temperature
sensing
elements 203 and 204 respectively, g is the acceleration of gravity and a is
the angle between
axis X and horizontal plane, as shown in Figure 2b, Then, a formula
calculating the angle a
between the axis X and the horizontal plant can Ix obtained: a = sill ~ (x1g).
Preferably, the
axis X of the tilting angle sensing unit 20 is parallel to the reference
surface 18 on the easing
1. In this case, the tilting angle of the axis X is the tilting angle of the
rafetnnco surface and
no additional calculation is needed.
[0022] By means of the above mentioned method, a precise mea~surerr~nt of a
tilting
angle relative to the horizontal plane can ba aahievcd in the range of 0-90
degrees. It should
be noted that while a tilting angle is close to 90°, the variation of
the difference betwoen the
output electronic signals from the two temperature sensing elements will not
ba big enough,
and as a result, it is difficult for the signal processing circuit to
precisely distinguish these
angles. However, in most cases, ttte above mentioned method can satisfy the
requirement for
tilting angle measurement.
[0023] According to another preferred embodiment of the present invention, the
tilting
attgla sensing unit 20 may further include another pair of temperature sensing
elements 205
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Attorney Iaoeket No. 4386 P 11b
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and 206 which are locaeed along the axis Y and symmetric about the heating
element, as
shown in Figuro 3a. The output terminals of the temperature sensing elements
205, 206 are
also connected to the signal processing unit of the measuring circuit. In this
embodiment, the
tilting angle sensing unit 20 is artanged vertically with its axis X parallel
to the reference
measuring surface and axis Y perpendicular to the reference measuring surface.
In this case,
the angle between the axis Y and a horizontal plane is 90° - a. Since x
a g sin a, then y = g
cos a, where y is the diffcn:rtce between the output signals from temperature
sensing
elements 205 and 206 which are located along the axis Y respdctively. From the
above
formulae, a= tari' (x/y) can be derived. In this ease, based on the arctangent
function, anglesi
close to 90° can bo precisely distinguished by the tilting angle
sensing unit. Moreover, the
measurement errors of the tilting angle sensing unit 20 at the axis X and the
axis Y, which
rtsult from the influence oP the ambient temperature and the elevated
temperature of the
measuring circuit itself, can thus be offset against each other. Therefore the
measurement
precision can be further improved.
The above description and drawings of the preferred embodiments arc only used
to describe and illustratie the principle and content of the present
invention, but not to limit
the claimed scope of the present invention. It will be understand by those
ordinary skilled in
the art that there will be other alternatives, modifications and equivalents
within the spirit and
scope of the present invention. The spirit and scope of the invention are
defined by the
appended claims.
