Note: Descriptions are shown in the official language in which they were submitted.
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"DIE CLOSURE UNIT OF AN INJECTION MOULDING
_ MA~INE"
The present invention relates to the die closure unit of a
plastics injection moulding machine including a device for ejecting
the finished moulding, which device includes a hydraulic piston-and-
cylinder unit (hydraulic cylinder), mounted on the movable die carrier,
and a coupling mean~ which is mounted on the ejector plate of the
injection moulding die and by mean~ of which the piston rod of the
hydraulic cylinder is connectable to the ejector plate, whereby at
least one coupling element, guided radially relative to the piston
rod, is engageable behind a coupling head of the piston rod by the
loading of a spring, which coupling element is displaceable from itæ
coupling position by means of an unlooking element in oppoRition to
the action of the spring.
In a known device of this type (AT PS 320 192), the coupling
between the piston rod and the ejector plate is automatically
released by the rearward movement of the piston rod as soon as the
e~ector plate has reached its basic rearward position. In such a
case, the coupling elements which arè jointly guided by the piston
rod run on inclined faces of a sleeve which surrounds the coupling
head. This operating principle necessitates a large axial dimension
for the coupling means which protrudes beyond the mounting plate in
the coupling direction.
It i~ al80 known to provide a die closure unit with a mounting
device for alternate mounting or releasing of the injection moulding
die on the die carriers (German PS 2 724 020~. When the injection
moulding die is changed the clamping pins of the mounting device,
acting as the components of the moulding die halve~, are
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necessarily inserted with the moulding die into the clamping space
of the die closure unit~ The moulding die halves are then placed,
in a centering manner9 against the clampin~ faces of the die carriers
in a movement which is parallel to the closure movem~nt of the
injection moulding die. A change of moulding dies of this type
presupposes that ths ma~imum opening width of the die carriers is
greater, by the length of the clamping pins, than is required for
the maximum installation depth of the injection moulding die.
On the basis of the prior art mentionedg the invention seek~
to develop a die closure unit of the above-mentioned type such that
the injection ~oulding die may be replaced substantially more quickly
and with fewer operational æteps.
According to the invention, this object is achieved in that
the unlocking element of the coupling means di~posed within the
mounting plate of the in~ection moulding die is actuable by means of
a member which is displaceably mounted in a bore which is formed in
the mounting plate and extends perpendicular to the coùpling axis~
and in that the lateral edges of the mounting plate abut against
guide elements of the die carrier for a ~ubstitution or replacement
movement of the injection moulding die parallel to the clamping fa¢e
of the die carrier.
.This sclution substantially contains a full integration of
th0 coupling means in fa~our of a replacement movement of the
inje¢tion moulding die which runs transversely to the coupling axis.
This concept presuppose3 that the unlocking element is actuable in
the injection moulding die via a bore which extends transversely to
th0 coupling axis.
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In this solution for achieving the object, the die carriers
are set at a reciprocal distance which is slightly greater, e.g.
approximately 1 mm greater, than the dimension for the depth of the
injection moulding die for the replacement operation of the injeotion
5 moulding die. The injection moulding die is then inserted between
the die carrlers as far as a stop in a movement which extends
exclusively perpendicular to the coupling axis. In such a case, the
injection moulding die is guided on the guide elementæ of the die
carriers and on their clamping faces. The coupling rod of the
e~ector device is then inserted into the coupling means, incorporated
into the injection moulding die, for automatic coupling. If it is
necessary to change the moulding die again, the unlo¢king element of
the coupling means is first actuated via tne bore formed in the
injection moulding die wholly independent of an axial movement of the
piston rod of the e~ector device. me uncoupled ooupling rod is
then extracted from the injection moulding die. me die carriers
are then set at a reciprocal distance which is only slightly greater
than the dimension for the depth of the injection moulding die.
~hen, by being guided on the guide elements of the die carriers and
by being euided on the clamping faces of these die carriers, the
injection moulding die is in turn removed from the clamping space
in a direction o~ movement which is perpendicular to the coupling axis,
A replacement opexation of this type iB not only easier, it
can also be carried out by less technical staff and with fewer
operational steps than iB possible with known systems. In addition,
there i8 a saving in the dimensions for the hydraulic drive means for
the die carriers because an opening width which corresponds to the
maximum installation depth of the injection moulding die is only in
fact required for the die cloaure unit.
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In many cases, it is advantageous to free, at least
for a short tiine, the interior space within the box-like die
carrier for the additional incorporation of special units -
the coupling rod of the ejector means spanning the interior
space. For this purpose, a piston rod portion, serving as a
coupling rod, is provided with identical coupling heads on
both ends and is connectable, by means of its coupling head
remote from the injection moulding die, to a further coupling
means which is mounted on another piston rod portion of the
ejector means and is identical to the coupling means mounted
on the ejector plate.
The method of attaching such a special unit, e.g. in
the form of a device for un-screwing threaded cores from the
moulding, is described, for example~ in German PS 2 806, 060.
The invention will be described further, by way of
example, with reference to the accompanying drawings in which:~
Fig. 1 is a slde elevation of a die closure un1t
partly in section;
Figs. 2 and 3 are side and front elevations of the
injection moulding die of the die closure unit including a
coupling means and de~ice for ejecting the moulding;
Fig. 4 is an enlarged sectional view through the
coupling means taken along the line IV-IV in Fig~ 3;
Figs. 5 and 5a illustrate the diametrical coupling
elements of the coupling means in co-operation with an
unlocking element or eccentric both in and out of the coupling
position;
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Figs. 6 and 7 are sectional views through the coupling means,
taken along the line VII-VII of Fig. 9, both in and out of the coupling
position;
Fie. a is an e~ploded view partly in section of the coupling
- 5 means ~sectional view through disc 20a taken along the line YIII-VIII
in Fi~.7);
Fig. g showæ a portion of the piston rod (1~,21) in the region
of the second coupling mean6 dispo~ed within the box-like die carrier;
Fig.10 is a view coxrespondin~ to Figs. 6 and 7, but on an
enlarged scale, of an alternative arrangement of the coupling means;
Fig~ 11 is an 0nlarged~ partially sectional,view through a
portion of the in~ection moulding die, taken along the line XI-XI of
Fig. 3 and including the driving device for the unlocking element; and
Fig. 12 is a part section through an alternative embodiment
of the arrangement of Fig. 11.
Fig. 1 shows the right-hand part of the die cloæure unit
- without the piston-and~cylinder unit for the drive of movable die
carrier 13 and without the mounting plate which carries this piston-
and-cylinder unit and which is supported on machine base 10. A
mounting plate and stationary die carrier 12 are mounted on slide rails
11 of the machine base lOo me piston rod 16 of the piston-and-
cylinder unit, mounted on the back of the mountine plate, extendæ
throu~h this mounting plate and abut~ against the pressure absorbing
plate 13b of the displaceable die carrier 13 via a pressure
transmitting plate 15. me end of the piston rod 16 which strikes
against the pressure transmitting plate 15 has a bore 19 formed therein
whioh forms the oylinder spa¢es for the piston-and-cylinder unit
(hydraulic cylinder) of the device for ejecting the moulding.
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A piston rod 18, 21 of this hydraulic cylinder i8 connected
to an ejector plate 27 of injection moulding dia 25 via a coupling
means 20. The box-lika die carrier 13 is displaceably mounted on
tie-rods 14 which are accommodated, at one end, by the mounting
plate and, at the other end, by the stationary die carrier 12.
The pressure absorbing plate 13b of the die carrier 13 i8 connected
to the clamping plate 13a Or this die carrier 13 ~ia supporting rib~
13c. me injection moulding die 25 comprises a mounting plate 25b
on the coupling side, a mounting plate 46 on the mouldine side, a
contour plate 25 r~hich is adjacent to the separating plane a-a, a
contour support plate 40, two spacers 25a which are disposed
symmetricall~ to the coupling axis h-h and define a free space 26
for the ejector plate 27 guided on guide pins 41, an ejector cover
plate 28 for anchoring the ejector pins 42, and a shaping plate 44
on the moulding side. The moulding is denoted by the reference
numeral 430
In the embodiment shown in the drawings, the piston rod 18,
21 of the device for e~ecting the moulding connects the piston of
the hydraulic cylinder of this de~ice to the ejector plate 27 and
compris0s two piston rod portion~ 18 and 21.
The piston rod 21 on the moulding die side ha identical
coupl~ng heads lb on both ends. With its coupling head 21b remote
fxom the in~ection moulding die 25, the piston rod is connectable to
a further coupling means mounted on the other piston rod portion 18.
This coupling means i5 identical to the coupling means 20 mounted
on the e~ector plate 27. The further coupling means 20 is mounted,
with a flange member 18f, on the piston rod portion 18 at the front
end by means of securing screw 18h. It is in a mirror-image
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disposition relative to the coupling means 20 on the moulding die
side. The coupling buttons 21b are each offset from the remaining
piston rod portion by means of a respective neck 21a. Each coupling
button 21b extends into a truncated cone 21c. When the piston rod
18, 21 is inserted into the coupling means 20, the casing surface
cover of this truncated cone 21c abuts against sliding faces 23a of
the coupling elements 23, which sliding faces are inclined relative
to the coupling axis h-h. ~he diametrically disposed coupling
elements 23 of the coupling meana are guided radially rela-tive to
1~ the piston rod 18, 21, and are thereby first pushed radially
outwardly by the in-going coupllng head 21b in opposition to the
action of ~prings 24. In the coupling positlon, the coupling
elements are affected by the loading of the initially tensioned
springs 24 and engage behind the coupling head 21b. In such a
ca3e, the~e ooupling element~ 23 abut against the neck 21a of the
coupllng rod 21. me guide paths 51 for the coupling elements 23
are formed by reces~es in a disc 20a of the coupling mean~ 20,
whlch disc is provided with opening 20~ ~Figs.8, 10). The disc
20a is partially sur~ounded by a sleeYe 20a'. The ooil springs 24
whioh load the coupling element~ 23, are each sccommodated in a
respective bore 23¢ formed ~n ea¢h coupling ele~ent 23. They abut
against the sleeve 20a'. The plate-lik~ coupling elements 23 abut,
with one broad side9 against the ejector plate 27 or, respectively~
against the front face of the flange member 18fl A~ can be seen
particularly from Figs.69 7 and 10, the guide paths 51 are dzfined
by ~egmental remaining regions 20e of the disc 20a which form guide
faces 25 for the coupling element~ 23 which are also guided on tbe
base face 20h of the disc 20a (Fig.8).
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In the case of the coupling means 20 on the moulding die side9
the sleeve 20a' i~ centred in an annular groove formed in the
ejector plate 27y as can be seen particularly from Fig~ 4. In the
ooupling position9 the coupling head 21b plunges into a central
recess 54 formed in the ejector plate 27. The disc 20a is mounted
on the ejector plate 27 by means of securing screws 38. The coupling
elements 23 are displaceable from their coupling position by means of
an unlocking element in opposition to the action of the springs 24.
An eccentrlc 33 may be used as an ~mlocking element (example Ehown in
Fig80 1~9 and the left-hand half of the coupling means in the example
shown in FigsO 10,11). ~t the rotational axis b-b (Fig.6) which
extend~ radially relative to the coupling axis _-h, the eccentric 33
i8 rotationally mounted with one bearing portion 31a in the disc 20aO
As can be seen from Fig.8 (top), the eccentric iB symmetrical on both
sides, i.e. has two planes of symmetry o-c and d-d. The eccentric
member 33c protrudes between the couplirlg elements 23 into the guide
paths 51. By rotating the eccentric 33 about 90 , the eccentric 33
arrives at an unlocked position or a locked position, which positions
are shown at the top of Fig~8 and oorre~pond to a ~oupling position
or a non-coupling position of the coupling elements 23, a~ shown in
Figs. 4 and 5 teach simNlt~neously), in Figs. 6 and 7 and in Fie.10
(again simultaneously). me eccentric member 33b, with its working
faces 33c, Is parallepiped-shaped and abuts against the ooupling
elements 23 alternately with it~ narrower or wider working faces 33c.
me eccentric 33 is actuable by means of a tool which is inEertable
axially in the bearing portion 33a via a bore 48 formed in the
mounting plate 25b (Figs. 10, 11, on the left). In such a case,
the tool engages with a multi edged profile into an internal edge 33d
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of the bearin~ portion 33a. The tool 79 thereby extends through
the sleeve 20a' via holes 37. As can be seen from Figs. 6 and 7,
two diametrically disposed eccentrics 33 are provided in the coupling
means 20. In the example shown in Figs. 10 and 11, the eccentric
33 is installed as an additional unlocking element because the
coupling elements 23 there are co~trolled by a differen~ type o
meAnsO In the embodiment shown in Figs. 10 and 11, the unlocking
element iQ a key 56 mounted in the disc 20a. This key is guided in
the segmental remaining regio~ 2Ge of the disc 20a by means of a
cylindrical shaft. The key is insertable by means of a driving means
between the coupling elements 23 for unlocking purposes in opposition
to the action of a coil spring 57, which surrounds the shaft. AR
can be seen from Fig~ll, the dri7inB means 76 is a hydraulic or
pneumatic piston-and-cylinder unit whose piston rod, as member 58,
is guided iD the bore 48 formed in the mounting plate 25b. ~ pin
59, anchored i~ the disc 20a, extends through a slot 77 formed in the
shaft of the key 56 (Fig.10). The portion of the shaft of the key
56 which i5 surrounded by the coil spring 57 protrudes into the free
space 55 of the mounting plate 2~ (Figs. 10-12). The cylinder o~
the driving means 76 is formed by a die-piece 62 which is mounted on
the clamping plate 13a of the die carrier 13 by means of securing
screws 63. The hydraulio or pneumatic cylinder is sealed by a cover
66 which haQ an inlet bore 65 formed therein for the hydraulio or
pneumatic medium. After every unlocking stroke, the piston is
reset into the basic po~ition by means of a resetting spring 64
which abuts, ~t one end, against a shoulder of the moulded-piece 62
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and, at the other end5 against the piston 58a. In the embodiment
shown in Figol2~ the driving means 76 comprises a coil 72, which i8
acoommodated in a moulded-piece 70, and an armature 71 which is
disposed within the coil 72 and is axially dri~able by me~n~q of
5 induction. The moulded-piece 70 is mounted on the clamping plate
13a of the die carrier by means of mounting screw 63. I~e armature
71 i8 connected to a pln-like member 68, which is resettable by means
of spring 67, ~ia a connecting rod 69. The spring is supported on
a ring of the member 68 and abuts against an annular shoulder Or the
ejector plate.
Gripper projections 78a of hydraulically actuable clamping pins
78 engage behind the mounting plate 25b of the injection moulding die
25 (Fig l). The clamping pins 78 extend through rail-like guide
elemente 75 which are detachably mounted on the clamping face of the
die carrier 13. The half of the injection moulding die which 18
hydraulically clamped tightly on the die carrier by means of the
clamping pins is released in that the hydraulio clamping i8 reduced
and the clamping pins 78 are guided by qpring force slightly in the
direction of the moulding die 25. By being guided on the guide
elements 75 and on the clamping faces of the die carriers 12~ 13, the
inJectlon moulding die 25 can then be guided out o~ the clamping space
of the die olosure unit in a replacement mo~ement extending
perpendlcular to the coupling axis h-h or, i~ the operational steps
are reversed, another moulding die may be inserted.
The eccentric 33 is axially secured by means of a radial flange
which is held between an annular shoulder 61 (Fig.lO) and the sleeve 20a'.
