U.S. patent application number 10/356485 was filed with the patent office on 2003-08-07 for toggle-type die clamping unit of an injection molding machine.
This patent application is currently assigned to TOSHIBA MACHINE CO., LTD.. Invention is credited to Hidaka, Yoshinori, Katoh, Fumiyuki, Katsuta, Hiroshi, Nishizawa, Makoto, Okuyama, Hiroshi.
Application Number | 20030145975 10/356485 |
Document ID | / |
Family ID | 27606498 |
Filed Date | 2003-08-07 |
United States Patent
Application |
20030145975 |
Kind Code |
A1 |
Katoh, Fumiyuki ; et
al. |
August 7, 2003 |
Toggle-type die clamping unit of an injection molding machine
Abstract
A toggle mechanism is supported at the front face of the housing
and a forward end of the toggle mechanism is connected to a back
face of the movable platen. Upon the closing and opening of dies,
the toggle mechanism is stretched and contracted to move the
movable platen forward and backward along the tie bars. An
automatic control device calculates, before the dies are mounted,
from a die thickness input and the kind of the dies input, such a
stop position for the link housing as impart a target value to the
stretching/contraction amount that the toggle mechanism has when
the dies are in closed state, and calculates, from the kind of the
dies input, an appropriate contraction amount greater than the
target value, and the automatic controlling device moves the link
housing to the stop position calculated and the toggle mechanism by
the appropriate contraction amount calculated.
Inventors: |
Katoh, Fumiyuki;
(Shizuoka-ken, JP) ; Okuyama, Hiroshi;
(Numazu-shi, JP) ; Hidaka, Yoshinori;
(Shizuoka-ken, JP) ; Katsuta, Hiroshi;
(Gotemba-shi, JP) ; Nishizawa, Makoto;
(Numazu-shi, JP) |
Correspondence
Address: |
PILLSBURY WINTHROP, LLP
P.O. BOX 10500
MCLEAN
VA
22102
US
|
Assignee: |
TOSHIBA MACHINE CO., LTD.
Tokyo
JP
|
Family ID: |
27606498 |
Appl. No.: |
10/356485 |
Filed: |
February 3, 2003 |
Current U.S.
Class: |
164/341 ;
164/137 |
Current CPC
Class: |
B29C 45/1751 20130101;
B29C 45/7653 20130101; B22D 17/26 20130101; B29C 45/661
20130101 |
Class at
Publication: |
164/341 ;
164/137 |
International
Class: |
B22D 033/04; B22D
017/26 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 6, 2002 |
JP |
2002-029831 |
Claims
What is claimed is:
1. A toggle-type die clamping unit of an injection molding machine
comprising: a base; a stationary platen fixed on the base and
configured to retain a stationary die; a movable platen arranged
opposite to the stationary platen and configured to retain a
movable die, the movable platen being configured to be supported on
the base in such a state as to be movable in forward and backward
directions; a link housing arranged on the base behind the movable
platen and adjustable in position in the forward and backward
directions; a toggle mechanism mounted to a front face of the link
housing and having a forward end which is connected to a back face
of the movable platen, the toggle mechanism being configured to
have its stretching/contraction amount controlled so as to move the
movable platen forward and backward to close and open the dies; a
detector configured to detect a position of the link housing on the
base and an automatic controlling device configured to control a
stop position of the link housing, wherein, before the dies are
mounted, the automatic controlling device calculates, from a die
thickness input, such a stop position for the link housing as
impart a target value to the stretching/contraction amount that the
toggle mechanism has when the dies are in closed state, and the
automatic controlling device moves the link housing to the stop
position calculated.
2. A toggle-type die clamping unit of an injection molding machine
comprising: a base; a stationary platen fixed on the base and
configured to retain a stationary die; a movable platen arranged
opposite to the stationary platen and configured to retain a
movable die, the movable platen being configured to be supported on
the base in such a state as to be movable in forward and backward
directions; a link housing arranged on the base behind the movable
platen and adjustable in position in the forward and backward
directions; a toggle mechanism mounted to a front face of the link
housing and having a forward end which is connected to a back face
of the movable platen, the toggle mechanism being configured to
have its stretching/contraction amount controlled so as to move the
movable platen forward and backward to close and open the dies; a
first detector configured to detect a position of the link housing
on the base; a second detector configured to detect the
stretching/contraction amount of the toggle mechanism; and an
automatic controlling device configured to control a stop position
of the link housing and the stretching/contraction amount of the
toggle mechanism, wherein, before the dies are mounted, the
automatic controlling device calculates, from a die thickness input
and the kind of the dies input, such a stop position for the link
housing as impart a target value to the stretching/contraction
amount that the toggle mechanism has when the dies are in closed
state, and calculates, from the kind of the dies input, an
appropriate contraction amount greater than said target value, and
the automatic controlling device moves the link housing to the stop
position calculated and the toggle mechanism by the appropriate
contraction amount calculated.
3. A toggle-type die clamping unit according to claim 2, wherein
the automatic control device calculates the appropriate contraction
amount when the type of dies input designates
spring-incorporated-type dies incorporating springs, said
appropriate contraction amount being corresponding to an opening
amount of the dies opened by the springs.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based upon and claims the benefit of
priority from the prior Japanese Patent Application No.
2002-029831, filed Feb. 6, 2002, the entire contents of which are
incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a toggle-type die clamping
unit of an injection molding machine and, in particular, to the
function of, before mounting operation of dies, automatically
stopping a link housing and movable platen to their appropriate
positions.
[0004] 2. Description of the Related Art
[0005] In an electric injection molding machine, a toggle mechanism
has been widely used as a die clamping unit. A primary section of
the toggle-type die clamping unit comprises a base, a stationary
platen, a movable platen, a link housing, a toggle mechanism, etc.
The stationary platen is fixed on the base and retains a stationary
die in place. The movable platen is arranged opposite to the
stationary platen and configured to retain the movable die and
supported on the base to be movable in forward and backward
directions. The link housing is arranged behind the movable platen
and can adjust the forward and backward positions on the base. The
toggle mechanism is mounted on a front face of the linked housing
and its forward end is connected to a back face of the movable
platen. Upon closing and opening of the dies, a
stretching/contraction amount of the toggle mechanism is controlled
to move the movable platen forward and backward.
[0006] Since, in the toggle-type die clamping unit, in order to
effectively utilize clamping force raising function of the toggle
mechanism, it is necessary that the position of the link housing be
initially adjusted so as to allow the stretching/contraction amount
of the toggle mechanism to reach a predetermined target value with
the dies in a closed state. If, therefore, the die thickness (a
total thickness of the stationary and movable dies in a closed
state) varies, it is necessary to adjust the stop position of the
link housing each time.
[0007] At a start of a die mounting operation in a conventional
injecting machine, the operator has initially adjusted the stop
positions of the link housing and movable platen as will be
described later, while operating push buttons on an operation panel
in a manual mode. That is, with associated dies not in a mounted
state, the stretching/contraction amount of the toggle mechanism is
adjusted and then it is stopped in a state to be contracted to some
extent for example, about 10 to 20 mm from a supposed position at a
die clamping time. Then, while confirming the distance between the
stationary platen and the movable platen by the eyes of the
observer, the position of the link housing is adjusted in
accordance with the thickness of the dies and, in a supposed state
allowing the insertion of the dies, the link housing is
stopped.
[0008] After, in this way, the stop positions of the link housing
and movable platen have been initially adjusted, the stationary and
movable dies are attached to the stationary and movable platens,
respectively. Then the stop position of the link housing is finally
fine-adjusted by clamping the dies by a predetermined die clamping
force and, in this state, bringing the stretching/contraction
amount of the toggle mechanism up to a predetermined target
value.
[0009] (Problem of the Conventional Die Clamping Unit)
[0010] In the conventional die clamping unit, as set out above,
when, prior to the die mounting operation, the stop position of the
link housing is initially adjusted so as to meet the thickness of
the dies used, the operator has confirmed, by the eyes, the
distance between the stationary platen and movable platen. For this
reason, it is not easy to accurately align the stop position of the
link housing with the appropriate position. It also needs a
cumbersome operation and it takes a lot of time to do so.
[0011] In the case where no accurate preliminary adjustment is
performed, in a final adjustment subsequent to the mounting of the
dies, more steps are required so as to fine-adjust the stop
position of the link housing. And more time is needed in the final
adjustment operation.
BRIEF SUMMARY OF THE INVENTION
[0012] The present invention has been achieved in view of the
problem encountered in the conventional toggle-type die clamping
unit and it is accordingly the object of the present invention to
provide a die clamping unit which can accurately and efficiently
perform a preliminary adjusting operation of a link housing's
position which has to be done prior to the mounting of the
dies.
[0013] A toggle-type die clamping unit of an injection molding
machine according to the present invention comprises a base; a
stationary platen fixed on the base and configured to retain a
stationary die; a movable platen arranged opposite to the
stationary platen and configured to retain a movable die, the
movable platen being configured to be supported on the base in such
a state as to be movable in forward and backward directions; a link
housing arranged on the base behind the movable platen and
adjustable in position in the forward and backward directions; a
toggle mechanism mounted to a front face of the link housing and
having a forward end which is connected to a back face of the
movable platen, the toggle mechanism being configured to have its
stretching/contraction amount controlled so as to move the movable
platen forward and backward to close and open the dies; a detector
configured to detect a position of the link housing on the base and
an automatic controlling device configured to control a stop
position of the link housing, wherein, before the dies are mounted,
the automatic controlling device calculates, from a die thickness
input, such a stop position for the link housing as impart a target
value to the stretching/contraction amount that the toggle
mechanism has when the dies are in closed state, and the automatic
controlling device moves the link housing to the stop position
calculated.
[0014] It is to be noted that the target value for the
stretching/contraction amount of the toggle mechanism is so set
that the die clamping force raising function by the toggle
mechanism becomes a maximal value, or its near value, when the dies
are in closed state.
[0015] Preferably, a toggle-type die clamping unit of an injection
molding machine according to the present invention has, in addition
to the detector (first detector) configured to detect the position
of the link housing on the base, a second detector configured to
detect the stretching/contraction amount of the toggle mechanism,
in which, before the dies are mounted, the above-mentioned
automatic controlling device calculates, from a die thickness input
and the kind of the dies input, such a stop position for the link
housing as impart a target value to the stretching/contraction
amount that the toggle mechanism has when the dies are in closed
state, and calculates, from the kind of the dies input, an
appropriate contraction amount greater than the target value, and
the automatic controlling device moves the link housing to the stop
position calculated and the toggle mechanism by the appropriate
contraction amount calculated.
[0016] It is to be noted that the above-mentioned appropriate
contraction amount for the toggle mechanism is so set in accordance
with the kind of the dies as to allow the distance between the
stationary platen and the movable platen to become a value
corresponding to the thickness of the dies plus a gap necessary to
the insertion of the dies.
[0017] In the case where, for example, spring-incorporated-type
dies (dies incorporating springs to open the dies) are used, the
above-mentioned automatic controlling device is so configured as
to, when the spring-incorporated-type dies are inputted as the kind
of dies, calculate the above-mentioned appropriate contraction
amount on the basis of the opening amount of dies opened by the
spring. That is, the above-mentioned appropriate contraction amount
is so set as to allow the distance between the stationary platen
and the movable platen to become a value corresponding to the
thickness of the dies opened by springs plus a gap necessary to the
insertion of the dies.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0018] FIG. 1 is a view of a structure diagrammatically showing a
toggle-type die clamping unit according to the present invention;
and
[0019] FIG. 2 is a flow chart showing one method for preliminarily
adjusting the positions of a link housing and movable platen before
the mounting of dies in the toggle-type die clamping unit of the
present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0020] FIG. 1 shows a structure diagrammatically showing a
toggle-type die clamping unit of an injection molding machine
according to the present invention.
[0021] In the Figure, reference numeral 1 shows a stationary
platen; 2, a movable plate; 3, a link housing; 4, a toggle
mechanism; 5, tie bars; 6, a stationary die; 7, a movable die; 10,
a base; 11, an encoder (a second detector); and 12, a displacement
detector (a first detector).
[0022] The stationary platen 1 and link housing 3 are arranged to
face each other on a base 10. The stationary platen 1 is fixed on
the base 10. The stationary platen 1 and link housing 3 are coupled
to each other by four tie bars 5. A threaded portion is provided at
an area of the tie bar where it extends through the link housing 3.
A nut 17 on the threaded portion of each tie bar 17 is attached to
the link housing 3. By driving the nut 17, a positional adjustment
of the link housing 3 is made in forward and backward (right and
left) directions on the base 10. The position of the link housing 3
is detected by means of the displacement detector 12 mounted on the
base 10.
[0023] The movable platen 2 is arranged between the stationary
platen 1 and the link housing 3. The tie bars 5 pass through the
four corner portions of the movable platen 2, respectively. The
movable platen 2 can be moved back and forth on the base 10. The
stationary die 6 is attached to the front surface (to the left in
the Figure) of the stationary platen while the movable die 7 is
attached to the front surface (to the right in the Figure) of the
movable platen 2.
[0024] The toggle mechanism 4 is attached to the front face of the
link housing 3. The forward end of the toggle mechanism 4 is
connected to a back face of the movable platen 2. Upon closing and
opening of the dies, the stretching/contraction amount of the
toggle mechanism 4 is controlled to allow the movable platen to be
moved forward and backward along the tie bars 5. The
stretching/contraction amount is controlled by driving a ball screw
21 through a pulley 18, a timing belt 20 and pulley 19 with the use
of a servomotor 16 and, by doing so, moving a crosshead 22 forward
and backward along the tie bars 5. The stretching/contraction
amount of the toggle mechanism 4 is detected by the encoder 11
attached to the servomotor 16.
[0025] In connection with this toggle-type die clamping unit, an
explanation will be made below about one method for preliminarily
adjusting the positions of the link housing 3 and movable platen 2
before the mounting of the dies. FIG. 2 shows a flow chart of the
preliminary adjustment in supposing the case of mounting a
spring-incorporated-type dies, that is, the dies with springs
incorporated to open the dies. It is to be noted that, in FIG. 2,
"LH" denotes the link housing and "MP" denotes the movable
platen.
[0026] Before mounting the dies 6 and 7, an unit operator selects a
"die mounting" mode on an operation panel and then inputs the die
thickness and springing amount (a die opening amount by the
springs) as input data. Then, the operator depresses an "automatic
die thickness adjustment" button. By doing so, the input data is
conformed and a corresponding LED starts to be flashed on and
off.
[0027] An automatic control device, not shown, of the die clamping
unit determines a stop position (XSL12L in the Figure) of the link
housing 3 based on the inputted die thickness and springing amount
so that the stretching/contraction amount of the toggle mechanism 4
in a die-closed state reaches a predetermined target value. On the
other hand, an appropriate value (XSL12 in the Figure) of the
stretching/contraction amount of the toggle mechanism 4 before the
mounting of the dies is so determined that a distance between the
stationary platen 1 and the movable platen 2 becomes a value
corresponding to the thickness of the dies opened by the springs
plus a gap necessary to insertion of the dies.
[0028] When the operator again depresses the "automatic die
thickness adjustment" button, the corresponding LED is lighted and
the link housing 3 and movable platen 2 start to be moved. The
automatic control device of the die clamping unit, while detecting
the position of the link housing 3 by the displacement sensor 12,
moves the link housing 3 to the appropriate position (XSL12L) set
out above. At the same time, it moves the movable platen 2 to the
above-mentioned appropriate position (XSL 12) while detecting the
stretching/contraction amount of the toggle mechanism 4 by the
encoder 11.
[0029] After the link housing 3 and movable platen 2 have been
brought to their appropriate positions and stopped there, the LED
is turned OFF and the preliminary position adjusting operation of
the link housing 3 and movable platen 2 has been completed.
[0030] Although, in the above-mentioned example, it is supposed
that the spring-incorporated-type dies are mounted, if normal-type
dies (dies not incorporating springs to open the dies) are mounted,
it is not necessary to consider the opening amount by the springs.
That is, the appropriate value (XSL12) of the
stretching/contraction amount of the toggle mechanism 4 before the
mounting of the dies is determined such that the distance between
the stationary platen 1 and the movable platen 2 becomes a value
corresponding to the thickness of the dies in a closed state plus a
gap necessary to the insertion of the dies.
[0031] According to the toggle-type die clamping unit of the
injection molding machine according to the present invention, it is
possible to accurately and efficiently make an adjusting operation
of preliminarily adjusting the positions of the link housing and
movable platen before the mounting of the dies.
* * * * *