Plastic and nonmetallic article shaping or treating: processes – With measuring – testing – or inspecting
Reexamination Certificate
1999-02-17
2001-12-04
Tentoni, Leo B. (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
With measuring, testing, or inspecting
C072S084000, C072S370230, C072S370260, C264S310000, C425S135000, C425S168000, C425S363000, C425S392000, C425S394000
Reexamination Certificate
active
06325953
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a plastic working method and a plastic working machine for plastically working a plastically workable tube by pressing plastic working tools.
2. Description of the Related Art
Hitherto, a spinning work machine as shown in
FIG. 18
has been known as one type of plastic working machines. In
FIG. 18
, the reference numeral
1
denotes a base and
2
a plastically workable tube, i.e., a workpiece, whose sectional profile is circular.
The reference numeral
3
denotes a chuck for clamping and holding the tube
2
by claws and
4
a tube supporting member fixed to the base
1
to rotably support the tube
2
around the axis of the tube
2
. The tube
2
is disposed so that the axial direction of the tube
2
coincides with the longitudinal direction of the base
1
by the chuck
3
and the tube supporting member
4
.
The reference numeral
5
denotes a stationary stage fixed via two leg members (one leg member
6
is seen in the figure) fixed on the upper surface of the base
1
,
7
a motor for spinning the tube
2
around the axis of the tube
2
(in the direction of so-called Z-axis) and
8
a decelerator fixed on the stationary stage
5
to decelerate the rotation of the motor
7
. The motor
7
is attached to the decelerators
8
.
The reference numeral
9
denotes a rotary shaft of the decelerator
8
, and
10
and
11
bearings fixed on the stationary stage
5
to rotably support the rotary shaft
9
of the decelerator
8
. The chuck
3
is attached at the end of the rotary shaft
9
of the decelerator
8
.
The reference numerals
12
and
13
denote linear way rails provided in parallel on the upper surface of the base
1
so as to extend in the longitudinal direction of the base
1
, i.e., in the axial direction of the tube
2
, and
14
a movable stage disposed on the linear way rails
12
and
13
so as to be movable along the linear way rails
12
and
13
.
The reference numeral
15
denotes a ball screw provided in parallel with the linear way rails
12
and
13
so as to move the movable stage
14
along the linear way rails
12
and
13
, and
16
a motor provided on the upper surface of the base
1
to move the movable stage
14
along the linear way rails
12
and
13
via the ball screw
15
.
The reference numerals
17
and
18
denote linear way rails provided in parallel on the upper surface of the movable stage
14
so as to extend in the direction of the width of the base
1
, and
19
and
20
movable stages disposed on the linear way rails
17
and
18
so as to be movable independently from each other along the linear way rails
17
and
18
.
The reference numeral
21
denotes a ball screw provided in parallel with the linear way rails
17
and
18
so as to move the movable stage
19
along the linear way rails
17
and
18
, and
22
a ball screw provided in parallel with the linear way rails
17
and
18
so as to move the movable stage
20
along the linear way rails
17
and
18
.
The reference numerals
23
and
24
denote motor mounting members fixed to the movable stage
14
,
25
a motor mounted to the motor mounting member
23
to move the movable stage
19
along the linear way rails
17
and
18
via the ball screw
21
, and
26
a motor mounted to the motor mounting member
24
to move the movable stage
20
along the linear way rails
17
and
18
via the ball screw
22
.
The reference numerals
27
and
28
denote plastic working rolls for plastically working the tube
2
by pressing against the tube
2
, and
29
and
30
plastic working roll holding members for holding the plastic working rolls
27
and
28
. The plastic working roll holding members
29
and
30
are fixed on the upper surface of the movable stages
19
and
20
, respectively.
This spinning work machine is constructed as described above to spin and work the tube
2
by continuously spinning the tube
2
around the axis of the tube
2
and by moving the movable stages
19
and
20
symmetrically in the radial direction of the tube
2
or by moving the movable stage
14
in the axial direction of the tube
2
in the same time and by pressing the plastic working rolls
27
and
28
against the tube
2
while controlling the relative position between the plastic working rolls
27
and
28
and the tube
2
. It allows tubular members as shown in
FIGS. 19A
,
19
B,
20
A and
20
B to be fabricated for example.
However, the primary object of the conventional spinning work machine shown in
FIG. 18
is to work the external shape of the tube
2
into a predetermined shape and is not provided with means for controlling the thickness of the tubular member fabricated by the spinning.
Therefore, the plastic deformation mechanism is decided univocally by the predetermined shape and the working process in spinning and working the tube
2
into the predetermined shape. As a result, it has had problems that the thickness of each part of the tubular member fabricated by the spinning work is univocally decided and that a tubular member having a desired thickness at each part cannot be fabricated.
For instance, the conventional spinning work machine has had a problem in fabricating a tubular member having an external shape as shown in
FIGS. 19A and 19B
that thickness of each part becomes thinner than the thickness before the work and that the part around the bottom of the concave portion indicated by an arrow A is thinned in particular, thus weakening the strength of this part most.
It also has had a problem in fabricating a tubular member having an external shape as shown in
FIGS. 20A and 20B
that the smaller the sectional area, i.e., the closer to the part where the tube should be shrunk more, the thicker the thickness is and that the thickness cannot be fixed.
The conventional spinning work machine shown in
FIG. 18
has had another problem that it is unable to fabricate a tubular member having an axially asymmetrical shape because the tube
2
is spun continuously around the axis of the tube
2
.
SUMMARY OF THE INVENTION
Accordingly, it is a primary object of the present invention to provide a plastic working method and a plastic working machine which allow a tubular member having a desired thickness to be fabricated by implementing spinning works while controlling the thickness of the tubular member.
It is a secondary object of the invention to provide a plastic working method and a plastic working machine which are arranged so as to be able to fabricate an axially asymmetrical tubular member which could not be fabricated by the conventional spinning work machine.
According to a first aspect of the invention, there is provided a plastic working method for plastically working a tube by employing tube holding and spinning means for holding and spinning the plastically workable tube around the axis of the tube and first and second plastic working tools which face to each other so as to pinch the tube in the radial direction of the tube and which are movable along the radial and axial directions of the tube while being pressed against the tube; wherein the plastic working method comprises a step of plastically working the tube by the first and second plastic working tools by continuously spinning the tube around the axis thereof and by applying compressive load or tensile load along the axial direction of the tube to the tube.
According to the first aspect of the invention, the step of plastically working the tube by the first and second plastic working tools by continuously spinning the tube around the axis thereof and by applying compressive load or tensile load along the axial direction of the tube to the tube is executed, thickness of each part of a tubular member fabricated by the spinning work may be controlled.
It is noted that the thickness of the spinning work part may be thickened when the compressive load along the axial direction of the tube is applied to the tube and the thickness of the spinning work part may be thinned when the tensile load along the axial direction of the tube is appli
Showa Denko K.K.
Tentoni Leo B.
LandOfFree
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