FR2497721A1 - MOLDING CLOSURE UNIT FOR INJECTION MOLDING MACHINE OF PLASTIC MATERIAL - Google Patents

Abstract

MOLD CLOSING UNIT OF A PLASTIC INJECTION MACHINE INCLUDING A MOLDED PART EJECTION DEVICE, WHICH INCLUDES A HYDRAULIC CYLINDER FIXED TO THE MOBILE MOLD HOLDER, AS WELL AS A COUPLING DEVICE FIXED TO THE MOLDED PART EJECTOR, THANKS TO WHICH THE ROD OF THE CYLINDER CAN BE COUPLED TO THE EJECTOR, A RADIAL COUPLING ELEMENT ACTING ON A COUPLING HEAD OF THE PISTON ROD UNDER THE LOAD OF A SPRING, THESE COUPLING ELEMENT CAN BE MOVED USING AN UNLOCKING ELEMENT. THE RELEASE ELEMENT OF THE COUPLING DEVICE 20 HAS INSIDE A FIXING PLATE 25B OF THE MOLD 25 CAN BE ACTUATED BY A BODY MOUNTED IN A HOLE OF THE FIXING PLATE 25B PERPENDICULARLY TO THE AXIS COUPLING. THE SIDE EDGES 25C OF THE FIXING PLATE 25A LIE AGAINST GUIDING ELEMENTS 75 OF THE MOLD HOLDER 13 FOR THE CHANGE OF THE INJECTION MOLD 25 IN PARALLEL TO THE CLAMPING SURFACE OF THE MOLD HOLDER 13.

Description

Mold closing unit for molding machine

injection of lastiarue material.

  The invention relates to the mold closing unit of a

  plastic injection molding machine

  a device for ejecting the finished molded part which

  includes a cylinder-piston hydraulic assembly (hydraulic cylinder

  lique) attached to the movable mold carrier, as well as coupling means attached to the ejection plate of the injection molding die by which the piston rod of the

  hydraulic cylinder can be coupled to the ejector plate

  at least one coupling member radially guided with respect to the piston rod acting from behind under the load of a spring on a coupling head of the piston rod, said coupling element being movable out of its mating position using an element of

  unlocking against the action of the spring.

  In a known device of this type (Austrian Patent NI 320 192), the coupling between the piston rod and the

  ejector plate is released automatically by the movement

  retraction of the piston rod as soon as the ejector plate has reached its starting position towards the rear. In this respect, the coupling elements driven together with the piston rod move on

  biased surfaces of a bushing surrounding the coupling head

  is lying. This operating principle necessarily leads to a large axial dimension of the coupling device which protrudes with respect to the fixing plate in

the direction of coupling.

  It is also known to equip a closure unit with

  with a fixing device for, alternatively, fixing the injection molding mold on the portermoule,

  or release it (German Patent N 27 24 020). When changing

  of the injection mold, the clamping bolts of this fastening device, as constituent elements

  injection mold halves, are necessarily in--

  produced with the injection mold in the clamping volume of the mold closing unit. Then, the halves of

  injection mold are applied in a parallel motion

  the closing movement of the injecticon mold on the clamping surfaces of the half-holder, centrally. Such an exchange of injection molding means that the maximum opening width of the mold carrier is greater than one to one, and this value is equal to the length of the clamping bolts to the maximum required. ime in depth of the mold of

injection-molded.

  From the state of the art indicated, the object of the invention is to provide a mold closing unit of the type mentioned at the beginning, which allows to change the injection casting mold substantially more quickly and with

less work of the staff.

  This goal is reached r; This is due to the fact that the unlocking element of the coupling device disposed in the vicinity of the fixing wall. The injection mold can be actuated by means of a member which is movably mounted in a channel neaga * erendicularly to the coupling axis in the attachment, and the lateral edges of the body. This information is based on

  guide elements of the porrte-mold for a parallel movement

  to the clamping surface of the holder

change of the injection mold.

  This solution essentially involves a total integration

  coupling device for the benefit of a movement

  change of the mold of a trans-

  to the coupling pin. This pre-conception

  assumes that the unlocking element can be actuated from a bore formed transversely to the coupling axis

in the injection mold.

  In this solution, for the change of the injection mold, the portemoule are adjusted to a reciprocal distance which is slightly larger, for example about 1 millimeter, than the depth dimension of the injection mold. The injection mold is then inserted between the mold holders to a stop in a movement that is only orthogonal to the coupling axis. The injection mold is thus fed to the guide elements of the mold carriers and also

  on their clamping surfaces. Then the coupling rod

  the ejector device enters the device

  integrated in the injection mold, for an accu-

  automatically. If a new change of injection mold is necessary, the unlocking element of the coupling device is first actuated from the injection mold bore, totally independently of axial movement of the piston rod of the injection mold. device

  ejector. The uncoupled coupling rod is then released

  part of the injection mold. The mold holders are then placed

  at a reciprocal distance which is only slightly larger

  that the congestion in depth of the injection mold.

  The injection mold, with guiding on the guiding elements

  of the mold holders and on the clamping surfaces of these portmolds, is again extracted from the volume of

  tightening following a direction of movement that is ortho-

gonal to the coupling pin.

  Such an exchange process is not only simpler, it can also be done by a less qualified staff, for a lower labor expenditure, than it is

  possible with known installations.

  Added to this is an economy from the point of view of

  hydraulic drive means of the mold carriers,

  because it is only necessary that the larator open

  ture for the mold closing unit which corresponds to the maximum space in depth of the injection mold. Other features of the invention can also contribute to obtaining a small size of the device

  coupling as required for the integration of the latter.

  In many cases, it is advantageous to release, at least

  momentarily, the internal space spanned by the stem of

  ejector device, within the mold-shaped mold carrier 13, for the additional adaptation of special units. For this purpose, a piston rod portion serving as a coupling rod is provided at each end.

  identical coupling heads and can be accom-

  its coupling head remote from the injection mold

  to another coupling device attached to another

  piston rod portion of the ejector device, this arrangement

  tif coupling being identical to that which is attached to the ejector plate. The advantage of such a special unit, for example in the context of a device for unscrewing threaded cores out of the molded part, is for example described

  in German Patent No. 2,806,060.

  An embodiment of the invention will now be disclosed.

  As an example, reference is made to the accompanying drawing, in which: Figure 1 shows the mold closing unit in side view and partly in section;

  FIGS. 2 and 3 show the injection mold of the unit

  mold closing tee equipped with the coupling device as well as the device for ejecting the molded part, in side and front view; Figure 4 is a section of the coupling device along the line IV-IV of Figure 3, on a larger scale;

  FIG. 5 represents the diametrical coupling elements

  the coupling device in cooperation with a

  unlocking element (eccentric) in the

and decoupling;

  Figures 6 and 7 show the coupling device

  sectional along the line VII-VII of Figure 9, in the coupling position and uncoupling;

  FIG. 8 represents the component parts of the device

  in the disassembled state (tray 20a cut

  VIII-VIII of Fig. 7), Fig. 9 shows a portion of the piston rod (18, 21) in the region of the second coupling device disposed within the box-shaped mold carrier. ; Figure 10 shows a variant of the coupling device in a representation corresponding to that of Figures 6 and 7, however on a larger scale; FIG. 11 shows a portion of the injection mold in section

  partial line along the line there of Figure 3, with the provision

  driving the unlocking element on a larger scale; and

  FIG. 12 represents a variant of the object of FIG.

re 11.

  Figure 1 shows the right-hand part of the closing unit.

  molding without the cylinder unit for driving the movable mold holder 13 and without the fixed mounting plate

  on the machine foot 10 and carrying this cylinder unit.

  The mounting plate and the stationary mold holder 12 are attached to sliding rails 1h of the machine foot

  10. The piston rod 16 of the cylinder unit attached to the

  the mounting plate passes through this plate of

  is supported by a transmission plate 15 of

  pressure on the pressure receiving plate 13b of the holder

  mold 13 movable. The end of the piston rod 16 abuts against the pressure transmission plate 15

  has a bored recess 19 which forms the cylindrical volumes

  driques for the cylinder unit of the device e éecticn the injected part. The piston rod 18, 21 of this hydraulic cylinder is connected by a coupling device 20

  to the ejector plate 27 of the injection mold. The door-

  mold 13 box-shaped is movably mounted on the side members 14 which are received at one end by the plate

  and at the other end by the mold carrier 12

  tionary. The pressure receiving plate 13b of the carrier

  13 is connected to the clamping plate 13a of this holder.

  mold 13 with reinforcing ribs 13c. The injection mold 25 comprises a coupling side a fixing plate 25b, injection side fixing plate 46, an adjoining contour plate 25 of the seal line a-a, a contour support plate 40, two spacers

  arranged symmetrically with respect to the h-h axis of accou-

  moreover, who dared. t a free space 26 for the plate

  ejector 27 mounted on guide pins 41, a coupling

  ejector loop 28 for anchoring the ejector pins 42

  as well as a plate 44 on the right side

  The molded part is designated by the reference 43. -

  The piston rod 18, 21 of the ejection device of the part

  molded, which connects the piston of the hydraulic cylinder of this dis-

  positive to the ejection plate 27. is constituted in the example

  full realization represented graphically by two parts

piston rod 18 and 21.

  The coupling rod 21, injection mold side, presents

  both ends of the heads 21.b identical.

  By its coupling head 21b remote from the injection mold

  it can be coupled to another coupling device

  attached to the other piston rod portion 18. This provision

  tif is identical to the coupling device 20 fixed to the ejector plate 27. The other coupling device 20 is fixed by a flange 18f on the front side to the piston rod portion 18 by means of fixing screws 18h. . It is symmetrically disposed at the coupling device 20 on the injection mold side. The coupling heads 21b are each offset from the rest of the piston rod portion

  thanks to a 21a collar. Each coupling head 21b is

  runs along a truncated cone 21c. The mantle of this truncated cone 21c, during the introduction of the piston rod 18, 21 into the coupling device 20, rests on the thrust surfaces 23a of the coupling element 23, which are inclined relative to the coupling axis hh. The coupling elements 23 of the coupling device which are arranged diametrically and guided radially with respect to the piston rod 18, 21 are thus first displaced radially outwards against the action of springs. 24 by the coupling head 21b entering into the coupling position, the coupling head 21b is grasped from behind by the coupling elements which

  are under the load of the prestressed springs 24.

  These coupling elements 23 thus rest on the neck 21a of the coupling rod 21. The guideways 51 for the coupling elements 23 are constituted by recesses in a plate 20a, having passage openings 20_q. (Figures 8 and 10), the coupling device 20. The plate 20a is partially surrounded by a sleeve a '. The coil springs 24 loading the coupling elements 23 are each received in a hole 23c of each coupling element 23. They abut the bushing

  at'. The plate-shaped coupling elements 23 become

  tap by a wide face against the ejector plate 27 or the front face of the flange 18f. as can be seen in particular in FIGS. 6, 7 and 10, the guide tracks 51 are separated from the residual zone 20e in the form of a circular segment of the plate 20a, which forms guide surfaces for the coupling elements 23 which are further guided

  on the base surface 20h of the plate 20a (Figure 8).

  In the case of the coupling device 20 mold side of

  jection, the sleeve 20a 'is centered in an annular groove

  2 of the ejector plate 27, as can be seen in particular in FIG. 4. The coupling head 2 plunges it into a coupling position in a central recess 54 of the ejector plate 27. The plate 20a is fixed by means of screws 38 to the ejector plate 27. The coupling elements 23 can be moved out of their coupling position and against the action of the springs 24 by means of a

  unlocking element. As an unlocking element

  lage, one can use an eccentric 33 (example shown in Figures 1 to 9 and left half of the device

  coupling of the example shown in Figures 10 and 11).

  The eccentric 33 is rotatably mounted by means of a portion of

  bind 31a in the plate 20a for an axis of rotation- b -'o

  (Figure 6) Radial to the coupling axis h-h.

  As can be seen in the upper part of Figure 8, the eccentric is made symmetrical on two sides, and it has two planes of symmetry c-c and d-d. The eccentric portion 33c enters the guideways 51 between the coupling elements 23. By a rotation of 90 of the eccentric 33, the latter reaches an unlocking position shown in the upper part of the figure

  9, or in a locking position, these positions correspond to

  laying at a coupling position or a non-coupling position of the coupling elements 23, as shown in FIGS. 4 and 5 (each time at the same time),

  Figures 6, 7 and Figure 10 (again at the same time).

  The eccentric portion 33b with its working surfaces 33c has a quadratic shape and alternatively bears by its narrowest or widest working surfaces 33c against the coupling elements 23. The eccentric 33 can be actuated at the by means of a tool that can be introduced axially into the bearing portion 33a through a hole 48 of the attachment plate 25b (Figures 10 and 11 left). A polygon profile of the tool then enters an inner surface 33d of the bearing portion 33a. The sleeve 20a 'is thus penetrated by the tool 79 by means of holes 37. As can be seen in FIGS. 6 and 7, two eccentric members 33 arranged diametrically can be provided in the coupling device 20. In FIG. example of

  FIGS. 10 and 11, the eccentric 33 is embodied as

  an additional unlocking element, since in this case the coupling elements 23 are controlled by a device of another type. In the embodiment shown in Figures 10 and 11, the unlocking element is a wedge 56 mounted in the plate 20a. This corner is guided in the residual area 20th of semicircular shape of the plate with a cylindrical rod. It can be introduced

  for unlocking between the coupling elements 23, -

  against the action of a helical spring 57 which

  with the aid of a driving device 76. The

  As shown in FIG. 11, the drive shaft 76 is constituted by a hydraulic or pneumatic cylinder whose piston rod, as an element 58, is guided in the hole 48 of the fixing plate 25b. An oblong hole 77 formed in the wedge rod 56 is traversed by a pin 59 anchored in the plate 20a (Figure 10). The portion of the wedge rod 56 which is surrounded by the helical spring 57 penetrates into the free space 55 of the fixing plate

  25a (Figures 10 and 11). The cylinder of the training device

  76 is formed by a shaped part 62 which is fixed to the clamping plate 13a of the mold carrier 13 by means of fixing screws 63. The hydraulic or pneumatic cylinder is closed by a cover 66 which has an inlet hole 65 for the hydraulic or pneumatic agent. After each unlocking stroke, the piston is returned to the starting position by means of a return spring 64 which abuts, on the one hand, against a shoulder of the shaped piece 62 and,

  on the other hand, against the piston 58a. In the variant represented

  shown in FIG. 12, the driving device 76 comprises

  takes a coil 72 housed in a form piece 70 and

  an armature 71 disposed inside the coil 72 and controlling

  axially by induction. The shaped piece 70 is fixed to the clamping plate 13a of the holder-holder by means of fastening screw 63. The armature 71 is connected by a connecting rod 69 to a bolt-shaped member 68 which can be moved back by the spring 67. The spring abutting against a ring of the member 68 rests against an annular shoulder

the ejector plate.

  The attachment plate 25b of the injection mold 25 is taken from behind by the gripping tongs 78a of hydraulically actuable clamp bolts 78. (Figure 1), the elements of

  75, in the form of bars, and fixed in a manner de-

  mountable to the clamping surface of the mold holder 13, are traversed by the clamping bolts 78. The half of injection mold - <ld..e hydraulic clamping to the mold holder by the bolts of ze. ' rabies is released when the

  hydraulic tightening is reloaded and that the bolts of sezra-

  ge 78 are slightly avra <in irection mold injection

  25 by the orce of a repsort. The injection mold 25 can then be evacuated according to its movement and its thickness and perpendicular to the accuplement axis hh, with guiding by means of guiding elements. do-shaped 12, 13, pr shooting setrrige space of the mold ferrmeture unit, another mold of inectiun

  which can be introduced in the process steps.

  Eccentric 33 is held axially by Air. radial rebrd which is trapped between an annular spoiler t1 (FIG.

) and the sleeve 20a '.

1l

Claims (10)

Claims.   A mold closing unit of a plastic injection molding machine comprising a device for ejecting the finished molding, which comprises a hydraulic piston-cylinder unit (hydraulic cylinder) attached to the movable mold carrier, and a coupling device attached to the ejector plate of the injection mold, whereby the piston rod of the hydraulic cylinder can be   coupled to the ejector plate, at least one element of ac-   coupling guided radially with respect to the piston rod acting from behind on a coupling head of the rod   piston under the load of a spring, said coupling member   plement able to be moved against the action of the spring out of its coupling position by means of an unlocking element, characterized in that the unlocking element (eccentric 33, corner 56) of the device coupling (20j disposed within a fixing plate (25b) of the injection mold (25) can be actuated by means of a member (58, 68, 79) which is movably mounted   in a hole (48) of the fixing plate (25b) and   to the coupling pin (h-h), and in that the lateral edges (25c) of the fixing plate (25a). rest against guiding elements (75) of the mold carrier (13) for an exchange movement of the parallel injection mold (25)   to the clamping surface of the mold carrier (13).   2. mold closing unit according to claim 1, characterized in that the unlocking element is a   wedge (56) mounted in a plate (20a) of the coupling device   (20) and which may be introduced by means of a   driving device (76) attached to the mold carrier (13), to the   against the action of a spring (57) between two coupling elements (23) arranged diametrically (FIG. Figure 11 right part).   3. mold closing unit according to claim 2, characterized in that the drive device (76) is a hydraulic or pneumatic cylinder unit whose piston rod (member 58) is guided in the hole (48) of the   fixing plate (25b) (Figure 11).   4. mold closing unit according to claim 2, characterized in that the driving device comprises an armature (71) surrounded by a coil (72) and can be controlled axially by induction which is connected by a rod link (69) to the recallable member (68) by a spring (67) (Figure 12).   Mold closing unit according to one of the claims   2 to 4, characterized in that an oblong hole (77) of the wedge (76) is traversed by a stationary stud (59) (Fig. 10), and in that the wedge rod (56) is surrounded by a spring helical (57.) enters a free space (55)   injection mold (25) (Figures 10 to 12).   6. Mold closing unit according to any one of   preceding claims, characterized in that the element   unlocking device is an eccentric (33) which is rotatably mounted   in a plate (20a) of the coupling device (20) (FIGS. 5 to 7, FIG. 10, FIG. 11, left part) and that it can be actuated in its bearing part (33a) by means of a tool pluggable axially through hole (48)   (Figure 10 and Figure 11 left).   7. Mold closing unit according to any one of   preceding claims, characterized in that the tracks   guide (51) for the coupling elements (23) are constituted by recesses in a plate (20a) provided with passage openings (20q in FIGS. 8 and 10) of the coupling device, which plate is partially surrounded by a socket Òa ') against which the springs   (24) coupling elements (23).   8. Mold closing unit according to any one of   preceding claims, characterized in that the elements   plate-shaped coupling (23) bears against a wide side against the ejector plate (27), and in that the coupling head (21b) of the coupling rod (21) is immersed in coupling position in a central recess (54) of the ejector plate (27). 9. Mold closing unit according to any one of   preceding claims, characterized in that the plate   for securing (25b) the injection mold (25) is grasped from behind by the gripping tongs (78a) hydraulically actuatable clamping bolts (78) (Fig. 1) and that the guiding elements (75) are form of bars and fixed to the mold carrier (13) are traversed by the bolts of tightening (78).   10. Mold closing unit according to any one of   preceding claims, characterized in that a rod   coupling (21) of the piston rod (18, 21) has at both ends identical coupling heads (21b),   and in that it can be coupled by its coupling head   (21b) away from the injection mold (25) with another coupling device attached to the piston rod portion (18), which device (20) is identical to the device   coupling (20) attached to the ejector plate (27).