Measuring and testing – Dynamometers – Responsive to force
Patent
1997-10-08
1999-03-23
Biegel, Ronald
Measuring and testing
Dynamometers
Responsive to force
73862581, 7386249, G01L 102
Patent
active
058862684
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL BACKGROUND
The invention is related to a method and a device for measurement of axial forces acting on an shaft. The invention also involves a method and a device for measuring the force on a measuring plate.
When taking measurements with certain types of measuring assemblies the need arises to measure axial forces which work on a rotating shaft or similar machine element. The axial force can be an integral part of the properties to be measured, but it may also be that the measurement of the axial force is a factor or condition connected with measurement of other forces or properties.
Force measurement is also used generally for measurement of, for example, forces which act against a measuring plate and which correspond to torque on an shaft.
STATE OF THE ART
Since the shaft is rotating during measurement, or can be rotated, certain problems occur partly in connection with recording the measurement signal and partly with transmitting the measurement signal to non-rotating parts of the measuring assembly. One customary method of avoiding these problems is to measure an axial displacement or motion caused by the force on the element by means of an indirect method instead of measuring the actual force which affects an shaft or another rotating element.
Use of such techniques brings about other problems instead, for example lessened exactness of measurement, decreased repeatability, and increased risk that the recorded measurement signals may wander.
Other problems which generally occur with devices for measurement of forces and torques are drift of the measurement signal as a result of high amplification and similar.
THE INVENTION IN SUMMARY
One objective of the present invention is to eliminate the above problems using indirect methods of measurement. The objective is achieved by means of the special features adapted by the invention, as indicated by patent claims 1 and 2. With these special features the invention has also been provided with other improved characteristics, which can be seen from the description below and the following patent claims. In an especially preferred embodiment a so-called air bearing, which is already well-known, has been modified and further developed. The method and device according to the invention are especially suitable for use within rheology, i.e., the measurement of the viscoelastic properties of a substance.
Another objective is to achieve a measuring device with low or undetectable drift and one which exhibits self-stabilizing characteristics. With the invention it also becomes possible to place required electronic components at a distance from the actual place of measurement.
The above indicated objectives are achieved by the invention's incorporation of the characteristics indicated in the independent patent claims given below. Further objectives and advantages with the invention emerge from the following description, drawings, and dependent patent claims.
SHORT DESCRIPTION OF THE DRAWINGS
The invention will now be described in more detail with help of various examples of the invention with reference to the accompanying drawings of which
FIG. 1 is a basic cross-sectional view of a device designed in accordance with the invention,
FIG. 2 shows the device schematically according to FIG. 1 in conjunction with a Theological measuring assembly,
FIG. 3 shows the device schematically according to FIG. 1 in conjunction with measuring bodies in a rheologically measuring assembly of a different embodiment than that described in FIG. 2,
FIG. 4 shows an alternative embodiment with both axial air bearings and radial air bearings,
FIG. 5 shows an alternative embodiment for measurement of various properties in rods,
FIG. 6 shows an embodiment of a device in accordance with the invention for measuring radial loading and displacement,
FIG. 7 is a sectional view of an alternative embodiment for measurement of torque, and
FIG. 8 is a side view of VIII--VIII of the embodiment in FIG. 7.
DESCRIPTION
In the embodiment according to FIG. 1, a device in accordance with th
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Biegel Ronald
Reologica Instruments AB
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