Measuring and testing – Surface and cutting edge testing – Roughness
Reexamination Certificate
1998-12-15
2002-06-04
Noland, Thomas P. (Department: 2856)
Measuring and testing
Surface and cutting edge testing
Roughness
Reexamination Certificate
active
06397667
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a surface property measuring device comprising a detector having, a stylus for measuring surface property, typically, surface roughness, and a driving mechanism for causing the detector to advance and retreat along a surface to be measured, more particularly to a surface property measuring device which is superior in straightness and reproducibility exhibited when the detector advances and retreats, and which is low in cost.,
Further, the present invention relates to a surface property measuring device comprising a detector having a stylus arm provided with the stylus in the vicinity of a leading end thereof, and more particularly to a surface property measuring device comprising a detector which is capable of measuring micro surface property by a low measuring force.
2. Description of the Prior Art
There has been widely used a surface roughness measuring device of applying a stylus on a surface to be measured, and measuring the surface roughness by detecting a surface roughness-direction-wise displacement of the stylus while advancing and retreating a detector including the stylus along the surface to be measured, to thereby convert the detected displacement into an electrical signal and then process the electrical signal in a predetermined manner.
There have been proposed various driving mechanisms for causing the detector to advance and retreat along the surface to be measured.
For example, there is, as shown in
FIG. 22
, described in Japanese Patent Publication (Kokoku) No. 4-60523 a surface roughness measuring device comprising a sliding shaft
34
held on a bearing
33
, which is disposed on a frame
32
of the driving mechanism, and sliding in an advancing and retreating, direction (in the direction shown by the arrow A) of a detector
10
, a driving-side connector
40
attached to the sliding shaft
34
through a moving block
36
and a leaf spring
38
, a feed block
44
fixed to the sliding shaft
34
through a connecting portion
42
for causing the sliding shaft
34
to advance and retreat in the direction shown by the arrow A, a feed screw
46
engaged with the feed block
44
, a reduction gear
50
connected to the feed screw
46
through a coupling
48
, and a motor
52
for rotation-driving the reduction gear
50
.
In
FIG. 22
, reference numeral
14
designates a detector-side connector pin attached to a rear end (on the right-hand end of the drawing) of a case
12
of the detector
10
and engaged with the driving-side connector
40
,
18
a stylus arm having a stylus
16
, which moves up and down while following the surface to be measured, at a leading end thereof (on the left-hand end of the drawing) and swinging in the case
12
with a fulcrum (
20
) as a center,
20
a leaf spring shaped like a substantially L, constituting the fulcrum of the stylus arm
18
,
22
an inductance type displacement detector disposed in the vicinity of a rear end of the stylus arm
18
for detecting an up-and-down movement of the rear end of the stylus lever
18
,
24
a skid for absorbing minute irregularities in the vicinity of the stylus
16
to thereby obtain a stable measured value, and
26
a nose for protecting the stylus
16
and the stylus arm
18
.
This Japanese Patent Publication (Kokoku) No. 4-60523 aims to propose a compact stationary surface roughness measuring device. However, it has a construction in which the sliding shaft
34
itself advances and retreats in the frame
32
of the driving mechanism
30
in the direction shown by the arrow A, thereby disabling the sliding shaft
34
to be elongated so much, which causes the moving stroke of the detector
10
to be placed under restriction. Furthermore, the sliding shaft
34
as a moving part is connected to the detector
10
through the moving block
36
, the leaf spring
38
, the connector
40
, and so on, thereby making the bearing
33
susceptible to the external force, which provides problems of making it difficult to maintain a stable and highly accurate straightness, and so on.
On the other hand, the applicant proposes in, Japanese Provisional Patent Publication (Kokai) Nos. 61-155901 and 61-155701 a stylus type measuring device in which, as its main part is shown in
FIG. 23
, a guide shaft
54
is fixed to a frame of a driving mechanism (not shown) in parallel with an advancing and retreating direction of a detector,
10
(in a lateral direction of the drawing), and the detector
10
is attached to a feed nut
45
which slides on the guide shaft
54
and is moved by a feed screw
46
rotated by a motor
52
.
In.
FIG. 23
, reference numeral
16
is a stylus,
56
a slide rod fixed to the feed nut
45
,
58
a vertical guiding member vertically connected to a leading end of the slide rod
56
,
60
is a sliding member attached to the vertical guiding member
58
slidably up and down,
62
a holding member to hold the detector
10
rotatably attached to the sliding member
60
,
64
a switch pin fixed to the feed nut
45
, and
66
,
68
are a fore end and a rear end limit switch which turn on at an advancing limit position (hereinafter referred to as “the fore end”) or an retreating limit position (hereinafter referred to as “the rear end”).
However, also the stylus type measuring device, proposed in Japanese Provisional Patent Publication (Kokai) Nos. 61-155901 and 61-155701 cannot sufficiently secure a span of the feed nut
45
to the guide shaft
54
; therefore, not only the feed nut
45
is easily susceptible to the external force, but also it undergoes a large saccadic movement due to the dimension error of the component, which does not makes it easy to maintain a stable and highly accurate straightness.
Besides, the applicant proposes in Japanese Utility Model Publication (Kokoku) No. 4-24408 a surface roughness measuring device in which, as its main part is shown in
FIG. 24
, a guide 'shaft
54
, is fixed to a frame
32
of a driving mechanism
30
in parallel with an advancing and retreating direction of the detector
10
(in a lateral direction of the drawing), and the detector
10
is attached to one of a pair of movable pieces
70
,
72
(the movable piece
70
in the drawing) which are moved by a feed screw
46
rotated by a motor
52
.
In
FIG. 24
, reference numeral
74
designates a pair of tension springs for urging both the movable pieces
70
,
72
in the direction nearer to each other to thereby eliminate the backlash.
However, also the surface roughness measuring device proposed in Japanese Utility Model Publication (Kokoku) No. 4-24408 has the same problems as Japanese Provisional Patent Publication (Kokai) Nos. 61-155901 and 61-155701.
On the other hand, there is described in Japanese Provisional National Publication (Kohyo) No. 8-503311 that a slide rod, to which a detector is attached, is positioned by being pressed obliquely on to an L-like slide surface in a driving mechanism by a leaf spring, a driving belt is engaged between pulleys disposed in the vicinities of a fore and a rear end of the driving mechanism, respectively, the slide rod is fixed to a part of the belt, and the rotation of the pulleys causes a detector, attached to a leading end of the slide rod, to retreat. The device proposed therein has a large saccadic movement due to the dimension error of the component, which makes it difficult to maintain. a stable and highly accurate straightness.
Furthermore, according to any one of the prior arts, the wire to the detector
10
in the driving mechanism
30
is made of a lead wire; therefore, according to the kind of the wire or the wiring manner of the wire, a part of the wire easily undergoes excessive bending, an unstable load, or the like is applied to a connector with the detector and a driving mechanism such as a sliding member, which provides a bad influence to the straightness and the reproducibility.
Besides, there are proposed, as a mechanism for supporting a stylus arm
18
in the detector
10
and providing a measuring force thereto, not only a mechanism provided w
Fujii Nobuyoshi
Sasaki Shinya
Shirai Tamenori
Ueda Satoshi
Mitutoyo Corporation
Noland Thomas P.
Oliff & Berridg,e PLC
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