Note: Descriptions are shown in the official language in which they were submitted.
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Removal mechanism for a plastic material injection moulding machine
Description
Field of the invention
The invention relates to a removal mechanism for a plastic material injection
moulding machine for processing plastic materials and other plasticisable
materi-
als, such as pulverulent or ceramic masses according to the preamble of claim
1.
State of the art
A removal mechanism of this type is known for example from EP 0 359 013 B 1.
The removal mechanism there is located above the injection moulding machine so
that its frame is supported directly on the injection moulding machine. Three
slid-
ing carriages thereby move a removal element in two horizontal and one
vertical
direction. The depositing of the removed parts is effected behind the machine.
However, a construction of this type presents problems in the case of machines
which are becoming even bigger, in particular with respect to the spatial
height re-
quired for this purpose. Comparable mechanisms with only one articulated arm
are known from EP 0 218 101 A 1, DE 36 13 074 A 1 or DE 23 52 736 B2.
A mechanism for converting a rotary motion of a driver disposed eccentrically
about
an axis of rotation into a linear motion of a sliding carriage is known from
WO
88/03238 A1, in which a plurality of drives is superimposed and in addition a
ro-
tary drive is provided. The motion is effected in a complex manner in a crank
guide
so that free pivotability of the sliding carriage is not provided.
Abstract of the invention
Starting from this state of the art, the object underlying the present
invention is to
produce a removal mechanism which can be used even in restricted spatial condi-
tions in connection with fairly large machines.
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This object is achieved by a removal mechanism having the features of claim 1.
A swivel drive is now provided, superimposed with the already known drive
units
for axes which are preferably situated orthogonally relative to each other.
The
swivel drive consequently supplements according to requirement the directions
of
motion which are present anyway and hence is able to contribute to an
accelerated
motion. Due to the superimposition of the four drives now present, a shorter-
term
engagement in the injection mould is possible so that the cycle times can be
short-
ened. The thus superimposed motion permits a significant reduction in the con-
l0 structional height so that a removal mechanism of this type scarcely
requires any
more spatial height than the constructional height of the machine itself.
Neverthe-
less, complex transmission mechanisms can be dispensed with. Only the use of
an
additional drive unit in the form of a swivel drive is required.
According to claims 8 and 9, the swivel drive is constructed such that
unequivocal
final positions are produced by means of stop members. The stop members con-
tribute both to precise positioning and to a reduction in subsequent
oscillation of
the removal element primarily in the case of larger removal mechanisms.
Further advantages are produced in the sub-claims.
Short description of the Figures
The invention is explained in detail in the following with reference to the
embodi-
went illustrated in the Figures, which show:
Fig. 1 a three-dimensional view of a part of a mould closing unit of an
injection
moulding machine with removal mechanism disposed adjacently in the
starting state,
Fig. 2 an illustration according to Fig. 1 with removal element inserted into
the
injection mould,
Fig. 3 an illustration according to Fig. 1 with retracted removal element and -
illustrated in broken lines - upright removal element,
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Fig. 4 an illustration according to Fig. 1 with removal element in depositing
po-
sition,
Fig. 5 an enlarged illustration of the swivel drive disposed on the second
sliding
carriage.
Detailed description of an embodiment
The Figures illustrate a removal mechanism for a plastic material injection
mould-
ing machine for removal of injection moulded parts from an opened injection
mould
illustrated in Figures 1 and 2. The plastic material injection moulding
machine
serves for processing plastic materials and other plasticisable materials,
such as for
example pulverulent or ceramic masses. Of the plastic material injection
moulding
15 machine 10, only a part of the mould closing unit F is indicated in the
Figures, said
mould closing unit being disposed on a machine base 14.
The mould closing unit F has a stationary mould carrier 11 and a moveable
mould
carrier 12 which, during opening and closing of the injection mould 15, is
moveable
via a non-illustrated closing unit cyclically towards the stationary mould
carrier
and away from the latter. Plasticisable material is injected by a non-
illustrated in-
jection moulding unit through the gate l la. The moveable mould carrier is
guided
along by bars 13. In order to remove injection moulded parts from the
injection
mould 15, a removal element 25 must be inserted into the opened injection
mould,
this process being intended to take place as quickly as possible since it
decisively
determines the cycle time and hence the productivity of the machine. The
removal
element 25 must also be able to be moved in between the bars 13 at the same
time,
which bars are required for transmitting the forces which are produced during
clo
sure of the mould and during injection. Alternatively, bars of this type can
however
be dispensed with as is known in the case of bar-less machines.
In the embodiment beside the injection moulding machine, a frame 20 is
provided
which has corner beams 22, 23 on legs 26. On both carrier beams 23 there are
located rails 21 with which a first sliding carriage S 1 is guided so as to
move hori-
zontally. The motion of the sliding carriage S 1 is effected via the drive A 1
which is
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mounted on the frame 20 in a stationary manner. The motion itself is effected
via
drive means which are not illustrated but are commonly known per se, such as
for
example belt drives, toothed belts, drive chains, linear drives or comparable
drive
means. The sliding carriage S 1 is hence moveable in a first direction of
motion x.
On this first sliding carriage S 1, a second sliding carriage S2 is guided so
as to
move horizontally along a second direction of motion y transversely relative
to the
first direction of motion x. The motion of the second sliding carriage S2 is
effected
via a second drive A2. On this second sliding carriage S2, a third sliding
carriage
S3 is in turn moveable in at least a third direction of motion z by means of a
third
drive A3. The third drive A3 is disposed on the second sliding carriage, more
pre
cisely on a swivel arm 32 which is still to be dealt with. Due to the motion
of the
third drive A3, a removal element 25 is inserted into the opened injection
mould
and moved out again. The removal element 25 is indicated merely schematically
in
the drawings but usually this concerns here generally known grippers.
A swivel drive A4 is provided on the second sliding carriage S2 and is used in
addi-
tion to the three drives which are actually normally already adequate. This
swivel
drive serves for pivoting the third sliding carriage S3 so that the latter is
transfer-
able from the normally present third direction of motion z, which has to date
gener-
ally been vertical according to the state of the art but can also be
horizontal, into a
fourth direction of motion superimposed by the co-operation of the drives A1,
A2,
A3 and the swivel drive A4. The co-operation of the drives hence makes
possible
both the required speed and the space-saving construction of the removal mecha-
nism so that the latter manages with a relatively small spatial requirement as
is
evident from Figure 3, which above all concerns the spatial height.
The swivel drive is formed by a belt drive. Instead, the swivel drive can for
example
also engage directly however on the swivel axis 30. In the embodiment, the
swivel
drive A4 transfers the third sliding carriage S3, which here is a removal rod,
from a
position in which the third sliding carriage is vertically moveable in the
third direc-
tion of motion z for example according to Figure 4, about the horizontal
swivel axis
30 into a position in which the third sliding carriage S3 is horizontally
moveable
according to Figure 2. The horizontal moveability of the third sliding carnage
S3 is
preferably parallel to the first direction of motion x so that, due to co-
operation of
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the drives A 1 and A3, an exceptionally rapid horizontal moveability in
ensured into
and out of the injection mould 15. This is made clear in Figure 2 by the
arrows x
and x' indicating the directions of motion. According to the actuation, the
drives
can be operated simultaneously or temporally offset.
The swivel angle of the swivel drive A4 is 90° in the embodiment. An
arm 31
mounted on the second sliding carriage S2 carries the swivel drive A4 which is
made clear in particular in Figure 5. The second sliding carriage S2 is spaced
via
the arm 31 approximately equally far from the swivel axis 30 as the third
sliding
l0 carriage S3 is via the swivel arm 32. The third sliding carriage S3 is
mounted on
the swivel arm 32 according to Figure 5, the drive A3 displacing the sliding
carriage
S3 relative to the swivel arm 32. The motion of the swivel drive A4 is limited
by
stop members 33 disposed on the arm 31 so that clearly defined final positions
are
produced. On the other hand, the swivel arm 32 has a trapezoidal projection 34
which covers a central angle of approximately 90°. The two stop members
33 are
disposed diametrically opposite on both sides of the swivel axis and hence at
a dis-
tance from each other of 180°. This arrangement leads to the fact that
the projec-
tion 34 abuts alternatingly on the two stop members 33 which leads therefore
to
the swivel angle of 90°. The abutting positioning effects that the
sliding carriage S3
2o which in certain circumstances is very long swings out relatively quickly
and hence
can be brought in a targeted manner for removal and also to the depositing
posi-
tion. In fact, the third drive A3 must be swivelled with it but the
combination with
the swivel drive permits a significant saving in space.
In the embodiment, the first direction of motion x is transverse relative to
the cen-
tral axis m of the plastic material injection moulding machine 10 or in other
words
transversely relative to the injection axis. The second motion mechanism is
sub-
stantially parallel to this central axis m. The removal mechanism stands in
vertical
projection substantially next to the mould closing unit F of the plastic
material in-
3o jection moulding machine so that the third sliding carriage S3 is
insertable horizon-
tally right into the opened injection mould 15.
The Figures display the course during removal of injection moulded parts.
Starting
from the starting position according to Figure 1, firstly the third sliding
carriage S3
is moved in the horizontal direction of motion using the drives A 1 and A3.
The
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speed of the insertion and withdrawal is determined by the superimposition of
the
motions in the direction of motion x and x'. If the moulded part is removed
from
the opened mould and if the sliding carriages S 1 and S3 are retracted, a
position
according to Figure 3 is produced in which therefore the sliding carriage S3
still
stands horizontally. If it is desired, there can however be effected
simultaneously a
swivel according to arrow 16 via the rotational drive and also, with co-
operation of
the third drive A3, a swivel in the third direction of motion z so that for
example a
representation corresponding to the representation of the sliding carriage S3
in
broken lines is produced. It becomes clear thereby how great the spacing is
relative
to the storage containers 40 so that the complete motion clearance does not
fun-
damentally require to be used. Fundamentally, these courses of motion can be
op-
timised above all by the simultaneous actuation of the drives A1, A2 and of
the
swivel drive A4. With this, the intended operation of a portal with an
articulated
arm drive is clear.
For positioning, the second drive A2 can be used in addition which leads to a
mo-
tion in the direction of motion y. According to Figure 4, the depositing in
the stor-
age container 40 is effected using the third drive A3 which this time however
acts in
the vertical direction. It becomes clear as a result that, despite the low
spatial
height required, a stroke of the third sliding carriage S3 down to the floor
is possi-
ble.
Instead of the second sliding carriage S2 which is equipped with the swivel
arm 32,
the entire removal mechanism can be equipped also with a sliding carriage
which
has no pivotable parts. Hence the sliding carriage S3 is only moveable in the
verti-
cal direction as dropping axis and the removal mechanism must then be con-
structed such that engagement into the injection mould is possible from above.
This has the advantage however for the manufacturer that the removal mechanism
can easily be adapted to the respective customer's requirements because of the
modular construction.
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Reference number list
Plastic material injection moulding
machine
11 Stationary mould carrier
5 11 a Gate
12 Moveable mould carrier
13 Bar
14 Machine base
Injection mould
1016 Arrow
Frame
21 Rail
22, 23 Carrier beams
Removal element
1526 Legs
Swivel axis
31 Arm
32 Swivel arm
33 Stop member
2034 Projection
Storage containers
A 1 First drive
A2 Second drive
A3 Third drive
25A4 Swivel drive
S 1 First sliding carriage
S2 Second sliding carriage
S3 Third sliding carriage
x, y, z, Direction of motion
x'
30F Mould closing unit
