Geometrical instruments – Gauge – With support for gauged article
Reexamination Certificate
1999-08-23
2001-04-03
Fulton, Christopher W. (Department: 2859)
Geometrical instruments
Gauge
With support for gauged article
C033S551000, C033S555000, C702S168000
Reexamination Certificate
active
06209217
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a surface-following type measuring machine, and more particularly to a surface-following type measuring machine which measures the surface roughness or contour of an object with a stylus thereof disposed in contact with the surface of the workpiece such that one of the stylus and the workpiece is moved relative to the other.
2. Prior Art
Surface roughness or contour measuring machines are known, which measure the surface roughness or contour of an object.
Measuring machines of this kind include a contact measuring machine having a contact-type stylus as shown in
FIG. 1
, which is equipped with a detector
5
comprised of a frame
10
which is moved relative to an object to be measured, by a moving mechanism, not shown, a measuring arm
11
supported via a shaft
12
by the frame
10
for swinging about the shaft
12
and carrying a stylus
15
at its tip, a balance weight
16
movably fitted on the measuring arm
11
, for adjusting a measuring force acting upon the measuring arm
11
, i.e. the force of contact of the stylus
15
with the object, such that the stylus
15
contacts the surface of an object to be measured with a predetermined measuring force, and a displacement detecting device
21
formed of a differential transformer or the like, for detecting an amount of displacement of the measuring arm
11
during swinging.
The measuring arm
11
is adapted to carry various types of styluses
15
and stylus holders
14
holding the stylus
15
such that the stylus
15
and the stylus holder
14
can be replaced with other ones, so as to be able to follow various surface contours of objects to be measured.
In measuring, a stylus
15
and a stylus holder
14
which are suitable for the surface contour of an object to be measured are selected and mounted on the measuring arm
11
. The stylus
15
of the measuring arm
11
is brought into contact with the surface of the object, and then the measuring arm
11
is moved along the surface of the object by the moving mechanism. The measuring arm
11
swings according to the surface contour of the object, whereby the amount of displacement of the measuring arm
11
during swinging is detected by the displacement detecting device
21
. The surface contour of the object or the like can be determined from the detected amount of displacement of the measuring arm
11
during swinging and the amount of movement of the same.
According to the conventional surface roughness or contour measuring machine, each time the stylus
15
and the stylus holder
14
are replaced with other ones, the balance weight
16
is adjusted, that is, the position of the balance weight
16
is moved in the longitudinal direction of the measuring arm
11
, using a tension gauge or an electronic scale, such that the force of contact of the stylus
15
with the object to be measured, i.e. the measuring force, becomes equal to a predetermined value. This adjusting operation causes degraded operation efficiency and forms a great burden on the operator.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a surface-following type measuring machine which is capable of setting the measuring force to a proper value in an efficient and accurate manner without imposing a burden on the operator in exchanging at least one of the stylus and stylus holder according to the surface contour of an object to be measured.
To attain the above object, the present invention provides a surface-following type measuring machine comprising a main body disposed for movement relative to an object to be measured, a measuring arm supported by the main body for displacement relative thereto, the measuring arm carrying at one end thereof a stylus holder and a stylus in a manner permitting replacement of the stylus holder and the stylus, displacement detecting means for detecting displacement of the measuring arm, measuring force adjusting means for adjusting a measuring force acting upon the measuring arm, storage means storing a measuring force command value table having a plurality of command values of the measuring force corresponding respectively to combinations of plural kinds of the stylus holder and plural kinds of the stylus, designating means for designating a kind of the stylus holder and a kind of the stylus after replacement of at least one of the stylus holder and the stylus, and control means for reading a command value of the measuring force corresponding to a combination of the kind of the stylus holder and the kind of the stylus after replacement designated by the designating means, and delivering the read command value of the measuring force to the measuring force adjusting means.
With the above arrangement, when the main body and the object to be measured are moved relative to each other with the stylus of the measuring arm disposed in contact with the surface of the object, the stylus of the measuring arm is displaced while following the surface of the object, and accordingly the measuring arm is displaced according to the surface roughness or contour of the object. The displacement of the measuring arm is detected by the displacement detecting means, and from the detected displacement value the surface roughness or contour of the object is determined.
When at least one of the stylus holder and stylus of the measuring arm is replaced with another kind of stylus holder and/or another kind of stylus according to the surface contour of the object to be measured, and the kind of stylus holder and/or the kind of stylus after the replacement is designated by the designating means, a command value of the measuring force corresponding to the combination of the kind of stylus holder and the kind of stylus designated by the designating means is read from the measuring force command value table, and the read command value of the measuring force is delivered to the measuring force adjusting means, which in turn controls the measuring force acting upon the measuring arm to a value corresponding to the read command value. As a result, the measuring force can be set to a proper value in an efficient and accurate manner without imposing a burden on the operator.
To attain the object, the present invention further provides a surface-following type measuring machine comprising a main body disposed for movement relative to an object to be measured, a measuring arm supported by the main body for displacement relative thereto, the measuring arm carrying at one end thereof a stylus holder and a stylus in a manner permitting replacement of the stylus holder and the stylus, displacement detecting means for detecting displacement of the measuring arm, measuring force adjusting means for adjusting a measuring force acting upon the measuring arm, storage means storing a measuring force command value table having a plurality of command values of the measuring force corresponding respectively to combinations of plural kinds of the stylus holder, plural kinds of the stylus, measuring directions in which the objected is to be measured, and angles of inclination of the main body, angle detecting means for detecting an angle of inclination of the main body, designating means for designating a kind of the stylus holder and a kind of the stylus after replacement of at least one of the stylus holder and the stylus, and for designating a measuring direction in which the objected is to be measured, and control means for reading a command value of the measuring force corresponding to a combination of the kind of the stylus holder and the kind of the stylus after replacement designated by the designating means, the measuring direction designated by the designating means, and the angle of inclination of the main body detected by the angle detecting means, and delivering the read command value of the measuring force to the measuring force adjusting means.
With the above arrangement, the measuring force command value table has a plurality of command values of the measuring force corresponding respe
Tsuruta Atsushi
Ueno Shuuzou
Fulton Christopher W.
Mitutoyo Corporation
Oliff & Berridg,e PLC
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