Geometrical instruments – Distance measuring – Opposed contacts
Reexamination Certificate
2002-08-14
2004-09-21
Gutierrez, Diego (Department: 2859)
Geometrical instruments
Distance measuring
Opposed contacts
C033S827000
Reexamination Certificate
active
06792690
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an inside micrometer. More specifically, it relates to an inside micrometer with reduced number of components.
2. Description of Related Art
As shown in
FIG. 8
, a conventional inside micrometer has an inside micrometer body
1
having a first spindle
11
advancing and retracting in accordance with rotation of a thimble
20
, a plurality of anvils
30
of mutually different lengths in increments of a predetermined dimension, and an extending collar
40
interposed between the anvil
30
and the inside micrometer body
1
.
As shown in
FIG. 9
, the inside micrometer body
1
has an inner cylinder
2
A having a through-hole
3
with an internal thread
4
being formed on the inner circumference thereof adjacent to a first end of the body, an outer cylinder
2
B provided on the outer circumference of the inner cylinder
2
A, a first spindle
11
composed of a cylindrical first spindle sheath
12
having an external thread
13
screwed to the internal thread
4
of the inner cylinder
2
A and a probe
15
screwed to the first end side of the first spindle sheath
12
, and a cylindrical thimble
21
covering a part of the inner cylinder
2
A and the outer cylinder
2
B from the first end to the second end opposite to the first end.
A plurality of slits
3
A are formed along cylinder axis of the inner cylinder
2
A adjacent to the first end, on which a nut
3
B is screwed from the outside. A setscrew
5
having a knob on the head thereof and a support knob
6
are screwed to the outer circumference of the inner cylinder
2
A on the second end side.
The outer circumference of the first spindle sheath
12
and an opening
21
A of the thimble
21
are fitted on the first end side in a taper
27
A of which diameter is increased from the first end side to the second end side, and are clamped by a nut
27
B screwed to the probe
15
.
A knurl
28
is formed on the outer circumference on the first end side of the thimble
20
and a scale
23
is carved on the outer circumference of the second end side thereof.
The diameter of the first end side of the anvil
30
is the same as the diameter of the through-hole
3
of the inner cylinder
2
A on the second end side, which widens at a step
31
on the halfway from the first end side toward the second end side. A probe
32
is provided on the second end side of the anvil
30
.
A scale
7
is carved on the outer cylinder
2
B in the axial direction of the cylinder.
The extending collar
40
has a through-hole
41
having the same diameter as the first end side of the anvil
30
.
In use, one of the anvils
30
of the length suitable for the target portion of the workpiece is selected, which is inserted into the inner cylinder
2
A from the second end side and held by the setscrew
5
. Subsequently, the thimble
20
of the inside micrometer body
1
is rotated to advance and retract the first spindle
11
. When the probe
32
of the anvil
30
and the probe
5
of the first spindle
11
are in contact with the workpiece, the dimension of the target portion of the workpiece is read from the scales
7
and
23
.
When the extending collar
40
is used, after the anvil
30
is inserted into the through-hole
41
of the extending collar
40
, the anvil
30
is inserted into the inside micrometer body
1
. Accordingly, the measurement area of the inside micrometer can be extended for the length of the extending collar
40
.
In actual measurement, the anvil
30
and the extending collar
40
are selectively attached to the inside micrometer body
1
according to the workpiece, thereby adjusting the measurement area of the inside micrometer as shown in FIG.
10
.
As an instance, it is assumed that the moving distance of the first spindle
11
of the inside micrometer body
1
is 13 mm, the length of the extending collar
40
is 12 mm and two anvils
30
for 50 mm and 75 mm length are prepared.
In order to measure the range for 50 mm to 63 mm, the anvil
30
for 50 mm length is attached to the inside micrometer body
1
.
In order to measure the range for 62 mm to 75 mm, the extending collar
40
as well as the anvil
30
for 50 mm length is attached.
In order to measure the range of 75 mm to 88 mm, the anvil
30
for 75 mm length is attached to the inside micrometer body
1
.
In the same manner, the anvil
30
and the extending collar
40
are selectively used to extend the measurement area. Accordingly, continuous area can be measured by preparing anvils
30
for different lengths in increments of 25 mm.
However, such a conventional inside micrometer requires anvils
30
of different lengths in increments of 25 mm.
For instance, in order to measure the range from 50 mm to 300 mm, no less than ten anvils
30
, i.e. anvils for 50 mm, 75 mm, 100 mm, 125 mm, 150 mm, 175 mm, 200 mm, 225 mm, 250 m and 275 mm lengths, have to be prepared.
According to the above, since the number of components are increased and many number of long anvils
30
have to be prepared, which requires much work and expensive cost. Further, since many number of anvils
30
have to be equipped, the size of accommodation case is increased, which is inconvenient in portable use.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an inside micrometer capable of reducing number of components and production cost, and suitable for portable use.
An inside micrometer according to and aspect of the present invention includes: an inside micrometer body including a cylinder having a through-hole, the inner circumference of the through-hole being provided with an internal thread, a first spindle screwed to the internal thread in an advanceable and retractable manner from a first end of the through-hole, and a thimble provided on the outside of the cylinder, the thimble being capable of rotating integrally with the first spindle; a plurality of anvils having different lengths in increments of a predetermined dimension, the anvil being capable of attachment and detachment on the second end opposite to the first end of the through-hole of the cylinder; a first extension member provided with a through-hole to which the anvil is inserted, the first extension member being selectively interposed between the second end side of the cylinder and the anvil to adjust a measurement range; and a second extension member having a second spindle which advances and retracts together with the first spindle, the second extension member being selectively attached to the first end side of the first spindle in an attachable and detachable manner.
According to the above arrangement, when the thimble is rotated, the first spindle rotates together with the thimble. Since the external thread of the first spindle is screwed to the internal thread of the cylinder, the first spindle advances and retracts from the first end side of the cylinder in an axial direction in accordance with the pitch of the screw. The distance for the first spindle to be advanced from the first end side of the cylinder to the outside is the moving distance of the inside micrometer body.
Conventionally, the anvil attached and detached on the second end side of the through-hole of the cylinder and the first extension member interposed between the second end side of the cylinder and the anvil are selectively used to adjust the moving distance of the inside micrometer with the measurement range in accordance with the length of the workpiece.
For instance, when a short anvil is solely used, the measurement range can be set short. When the first extension member is additionally used, the measurement range can be extended by the length of the first extension member. When the anvil is exchanged with a longer one, the measurement range can be further extended, and the measurement range can be adjusted in the same manner.
When the second extension member selectively used together with the anvil and the first extension member is used, following advantages can be obtained.
As described above, after an anvil of a predetermined length is attached to the ins
Konishi Tadashi
Shibahashi Minoru
Terui Katsunobu
Gutierrez Diego
Mitutoyo Corporation
Smith R Alexander
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