Chucks or sockets – Socket type – Fluid-conduit drill holding
Reexamination Certificate
2000-02-17
2001-10-23
Bishop, Steven C. (Department: 3722)
Chucks or sockets
Socket type
Fluid-conduit drill holding
C408S057000
Reexamination Certificate
active
06305696
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an improvement of a tool holder for a machine tool, particularly relates to a tool holder suitable for a dry cutting work.
DESCRIPTION OF THE RELATED ART
In processing with a machine tool, a large amount of cutting oil is supplied to a cut part in order to cool down and lubricate a workpiece and a cutting edge, and to remove cutting chips. This causes various problems such as environmental pollution, adverse influence on human health, high cost in treating waste oil, lower longevity of a cutting edge due to excessive cooling of the workpiece, firictional wearing of the cutting edge due to excessive oil supplied during fine processing. Besides, since a large amount of cutting oil adheres to chips during processing, it is necessary to remove the cutting oil from the chips to treat and recycle them.
To solve the above problems, a very small amount of cutting oil is atomized and supplied to a cut part of the workpiece of late. This treatment is called dry cutting.
In this dry cutting, it is easy to supply a mist of cutting oil to the tip of the cutting edge during processing a relatively shallow part of the workpiece. This is carried out by fixing a spray nozzle beside the cutting edge. However, it is actually difficult during processing a relatively deep part of the workpiece. To cope with this problem, cutting oil is supplied into the cutting edge from a main spindle body, and spouted from the tip of the cutting edge during processing.
FIG. 4
is a cross-sectional view of a conventional embodiment. The numeral
1
is a main spindle supporting frame for a machine tool, and
2
is a main spindle that is rotatably inserted therein by means of bearings
3
. The numeral
4
is a canister that rotatably holds steel balls
4
a
for engagement at the tip of the main spindle. The numeral
5
is made into a ring for fixing the canister
4
to the main spindle
2
. A front face of the ring
5
is a vertical flanged end face (m), and a central hole of the ring
5
comprises a flaringly inclined face (n) (which is called a tool shank taper). The numeral
6
is a clamp rod that slidably go back and forth in the main spindle
2
.
In
FIG. 4
,
7
is a tool holder having a cutting edge
8
at the tip. A grip
7
a
is formed at an outer circumference of the holder
7
so as to be held at an automatic exchange for the cutting edge. In addition, a longitudinal through hole (s) is provided in the center of the tool holder
7
. One side of the through hole (s), which the cutting edge
8
is installed into, is formed as an internal thread. A tool stopper
7
b
that moves in accordance with the length of the cutting edge
8
is screwed on the internal thread. The other side of the through hole (s) is provided with a conical engaging body
7
c
that protrudes outwards. The conical engaging body
7
c
are in contact with both the front end face (m) and the taper (n) of the ring
5
. Besides, it has a round hole
7
d,
into which the steel balls
4
a
of the canister
4
are freely inserted.
When the conical engaging body
7
c
is inserted into tile central through hole of the ring member
5
, the clamp rod
6
is pulled to an arrow direction (a) by means of a non-illustrated spring mechanism. Then, the steel balls
4
a
protrude from a round hole
4
b
of the canister
4
to the round hole
7
d,
thereby causing the tool holder
7
to be engaged with the main spindle
2
. Here, the conical engaging body
7
c
is in firm contact with both the end face (m) and the taper (n).
In the above embodiment, the cutting oil is supplied into a central hole
6
a
of the clamp rod
6
by a non-illustrated cutting oil feeder. Then. it flows into the through hole (s) of the tool holder
7
from the tip of the central hole
6
a,
and further into a central through hole (h) of the tool stopper
7
b
and an internal through hole (t) of the cutting edge
8
in tile tool holder
7
. Then, it is sprayed from the tip of the internal through hole (t).
In the above conventional embodiment, a cross-sectional area (s
1
) of a path in the clamp rod
6
, a cross-sectional area (s
2
) of a path in the tool holder
7
, and a cross-sectional area (s
3
) of a path in the tool stopper
7
b
are various as shown in the figure. In addition, the cutting oil is supplied at a constant pressure. However, since the main spindle
2
and the tool holder
7
having the cutting edge on the tip thereof are rotated in high-speed, mist grains of atomized cutting oil may be centrifuged and liquidized by the centrifugal force caused by their rotations. This prevents the cutting oil from flowing smoothly.
SUMMARY OF THE INVENTION
An object of the invention is to solve the above problems.
A tool holder for a machine tool of this invention has the following structures. A grip
10
a
is provided on an outer circumference of the tool holder
10
to be held on an automatic exchange of a cutting edge
8
. A through hole
10
b
is provided in the longitudinal center of the tool holder
10
. An internal thread (g) is provided on one end of the through hole
10
b,
and a tool stopper
11
screwed on the internal thread (g). A through hole
11
a
is provided in the longitudinal center of the tool stopper
11
. A conical engaging body
10
c
is provided on the other end of the through hole
10
b,
so that the conical engaging body
10
c
protrudes outwards. Because the conical engaging body
10
c
connects with a tool shank taper (n) and a flanged end face (m) of a main spindle, the tool holder
10
is constrained by two faces. A mist receiving tube
12
is provided on a connecting side of the through hole
10
b,
and a through hole
12
a
is provided in the longitudinal center of the mist receiving tube
12
. A communicating tube
14
is provided in the through hole
12
a
of the mist receiving tube
12
and the through hole
11
a
of the tool stopper
11
, so that the communicating tube
14
bridges them to flow cutting oil directly thereinside. Besides, the communicating tube
14
can suitably slide in the through hole
12
a
in accordance with motions of tool stopper
11
due to the different length of cutting edge
8
.
According to this invention, the mist receiving tube is provided to the tool holder on its connecting side with the main spindle, and the communicating tube is provided between the mist receiving tube and the tool stopper so as to bridge them. Therefore, the cutting oil are supplied directly from the main spindle to the cutting edge with as least resistance as possible caused by different steps.
Accordingly, the present invention has the following effects.
Especially in a dry cutting, in which a cutting oil is atomized, mist grains are not centrifuged nor liquidized by the centrifugal force due to rotations of the tool holder. Besides, the cutting oil can flow smoothly and efficiently.
REFERENCES:
patent: 4640652 (1987-02-01), Rivera, Jr.
patent: 5076740 (1991-12-01), Petrie
patent: 5674031 (1997-10-01), Bilz
patent: 6135679 (2000-10-01), Kazda
Kobayashi Takashi
Sugata Shinsuke
Anderson Chad C.
Bishop Steven C.
Horkos Corporation
Shannon John P.
Venable
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