US010675800B2

(12) Armbruster
United States Patent ( 10 ) Patent No.: US 10,675,800 B2
(45 ) Date of Patent: * Jun . 9 , 2020
(54 ) INJECTION MOULDING DEVICE HAVING A (58 ) Field of Classification Search
ROTATABLE CENTRE PART CPC B29C 45/0441 ; B29C 45/045 ; B29C
45/1628 ; B29C 45/1742 ; B29C 45/2606 ;
(71) Applicant: FOBOHA (Germany) GmbH , Haslach (Continued )
(DE )
( 72 ) Inventor: Rainer Armbruster , Wolfach (DE ) (56 ) References Cited
(73 ) Assignee : FOBOHA (GERMANY) GMBH , U.S. PATENT DOCUMENTS
Haslach (DE ) 4,408,981 A 10/1983 Brown
4,929,166 A 5/1990 Disimone
( * ) Notice: Subject to any disclaimer, the term of this (Continued )
patent is extended or adjusted under 35
U.S.C. 154 (b ) by 0 days . FOREIGN PATENT DOCUMENTS
This patent is subject to a terminal dis
claimer . CH 705 140 A2 12/2012
CN 1950186 A 4/2007
(21) Appl. No.: 16 / 194,003 (Continued )
( 22 ) Filed : Nov. 16 , 2018 Primary Examiner James P Mackey
(74 ) Attorney, Agent, or Firm Pauley Erickson &
(65 ) Prior Publication Data Kottis
US 2019/0084205 A1 Mar. 21, 2019
Related U.S. Application Data (57) ABSTRACT
(62) Division of application No. 14 /776,381 , filed as The invention relates to a retaining device for a rotatable
application No. PCT/EP2014 /054715 on Mar. 11 , center block in an injection molding device , comprising a
2014 , now Pat. No. 10,131,078. lower rotary plate rotatable about an axis of rotation and
driven by a motor, the lower rotary plate being used for
(30 ) Foreign Application Priority Data retaining the rotatable center block . The retaining device
comprises a lower cross member, which is mounted mov
Mar. 15 , 2013 (CH ) 0613/13 ably in the longitudinal direction (x ) on guide rails while
Dec. 13 , 2013 (CH ) 2062/13 supported on a machine bed of the injection molding device
by means of first bearing blocks. The retaining device can
(51) Int. Cl. have two bearing blocks, by means of which the lower cross
B29C 45/04 ( 2006.01 ) member is supported in the circumferential direction relative
B29C 45/17 (2006.01 ) to lower beamsof the injection molding device . For a further
(Continued ) increase in efficiency , the center block has a main body made
(52 ) U.S. Cl. of a material of lower density than a coupling plate opera
CPC B29C 45/2606 (2013.01 ); B29C 45/045 tively connected thereto .
(2013.01) ; B29C 45/1628 (2013.01);
(Continued ) 14 Claims, 2 Drawing Sheets
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 US 10,675,800 B2
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(51) Int. Ci. 6,503,075 B1 1/2003 Schad

B29C 45/26 (2006.01 ) 7,134,869 B2 11/2006 Lichtinger
B29C 45/16 (2006.01 ) 8,360,764 B2 1/2013 Armbruster et al .
B29C 45/32 ( 2006.01 ) 8,469,693 B2 6/2013 Schad
8,672,668 B2 3/2014 Armbruster
(52) U.S. CI. 8,764,434 B2 7/2014 Armbruster
CPC B29C 45/1742 ( 2013.01); B29C 45/2681 10,131,078 B2 * 11/2018 Armbruster B29C 45/1628
(2013.01 ); B29C 2045/1764 (2013.01 ); B29C 2014/0134366 A1 5/2014 Armbruster
2045/326 (2013.01) 2014/0308388 A1 10/2014 Armbruster
(58 ) Field of Classification Search 2016/0039136 Al 2/2016 Armbruster
CPC B29C 45/2681; B29C 2045/326 ; B29C
2045/328 FOREIGN PATENT DOCUMENTS
See application file for complete search history. EP 1 035 959 B1 9/2000
EP 1 119 449 B1 8/2001
(56 ) References Cited EP 1 155 802 A2 11/2001
EP 1 725 386 A1 11/2006
U.S. PATENT DOCUMENTS JP HO2 171221 A 7/1990
WO WO 2007/082394 Al 7/2007
5,578,333 A 11/1996 Schad WO WO 2011/107395 9/2011
5,772,420 A 6/1998 Holmes
6,099,784 A 8/2000 Teng * cited by examiner
U.S. Patent Jun . 9 , 2020 Sheet 1 of 2 US 10,675,800 B2
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U.S. Patent Jun . 9 , 2020 Sheet 2 of 2 US 10,675,800 B2
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 US 10,675,800 B2
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INJECTION MOULDING DEVICE HAVING A center part mounted on the machine bed . The holding device
ROTATABLE CENTRE PART in the invention is fully detached from the tie bars and has
no operative connection with these . All occurring forces are
CROSS REFERENCE TO RELATED transmitted via the machine bed .
APPLICATIONS 5 An object of the invention is to further improve the
injection molding devices known from the prior art with
This application is a Divisional Patent Application of U.S. respect to their efficiency.
patent application Ser. No. 14 /776,381, filed on 14 Sep. SUMMARY OF THE INVENTION
2015 , which is a 371 filing of PCT/EP2014 / 054715 , filed 11
Mar. 2014 , which claims the benefit of Swiss Patent Appli- 10
cation CH 00613/13 , filed 15 Mar. 2013 and Swiss Patent Reduction of cycle times is a viable means to increase
Application CH 02062/13 , filed 13 Dec. 2013. The co production capacity . However, at the higher processing
pending parent and related Patent Applications are hereby speeds associated therewith , increased forces also occur, as
incorporated by reference herein in its entirety and is made the machine parts must be more strongly accelerated and
a part hereof, including but not limited to those portions 15 decelerated so that they can keep up with the pace of the
which specifically appear hereinafter . machine. Optimal introduction and transmission of forces is
an important aspect in order to be able to guarantee the
BACKGROUND OF THE INVENTION robustness and durability of the device . Negatively impact
ing constraining forces are to be avoided . One aspect of the
Field of the Invention 20 invention consists of targeted optimally apportioning the
forces and the flow thereof across a plurality of machine
The present invention relates to the field of tools and elements. Thereby, the weight loads and the torques that act
machines for injection molding of plastic and other thermo between a rotatable mold center part (center block ) or a
plastic materials. holding device therefor, respectively , and an injection mold
25 ing machine, are partially or completely separately trans
Discussion of Related Art mitted . Another aspect of optimization is the targeted weight
reduction of certain parts .
Injection molding devices having one or more rotating A holding device according to the invention can be
center parts are known from the prior art . These are used for configured in several ways. In a preferred embodiment, the
the efficient manufacture ofmulti-component plastic parts 30 device has at least one base ( lower holding device ), the base
by injection molding . At least one rotatable mold center part being supported on a machine bed of the injection molding
(center block ), which is fixed to a holding device and is machine and displaceable in the longitudinal direction oftie
rotatably arranged about an axis of rotation , is arranged bars of the injection molding machine .
between two mold halves , the mold halves being movable A variant of the invention comprises a holding device for
against one another along tie bars in a first direction . The 35 a mold center part in an injection molding machine, themold
rotatable mold center part has at least two parallel side center part being rotatable about a vertical axis . The holding
surfaces, along which it interacts with the two mold halves device has a lower rotary plate which is rotatable about an
for the formation of the cavities. In certain embodiments, the axis of rotation and which is driven by a motor , the rotary
rotatable mold center part can interact at least on one side plate serving to receive and hold the rotatable mold center
with a further rotatable mold center part. Coordinating 40 part (center block ). If necessary, a plurality of holding
means effect that the rotatable mold center part remains devices can be arranged one behind the other. The lower
positioned centrally between the two mold halves during rotary plate is arranged rotatably about a vertical axis with
opening and closing, and thus collisions are avoided . Several respect to a lower cross member. The lower cross member is
holding devices for the rotatable middle part are known from movably mounted in the longitudinal direction of the injec
the prior art. 45 tion molding machine via first bearing blocks and guide rails
EP1035959 and EP1155802 were published in 1999 by being supported on a machine bed of the injection molding
the same applicant, and both relate to a holding device for machine .
a rotatable center part (mold , mold half,mold carrier). The The holding device may comprise second bearing blocks,
holding device has a lower and an upper cross member by means of which the lower cross member is supported in
which are guided along the tie bars of an injection molding 50 the circumferential direction relative to a pair of lower tie
machine . Each cross member of the holding device has a bars of the injection molding machine. To avoid negative
rotatable holdingmeans , which serves for releasable clamp forces relative to the tie bars, the second bearing blocks can
ing the mold , mold half or the mold carrier therebetween . be floatingly mounted at least in the vertical direction
EP1725386 of the same applicant was published in 2005 , relative to the lower cross member. Alternatively or addi
and relates to a method and an injection molding device with 55 tionally, the second bearing blocks can be adjustably
more than one rotatable center part. This makes it possible arranged relative to the lower cross member. Depending on
to manufacture parts in two outer parting planes and to the area of application , the second bearing blocks can form
assemble these in a further parting plane in a further manu a unit with the first bearing blocks. The second bearing
facturing step . In the figures, different embodiments of blocks may at least partially engage around the tie bars from
holding devices for the rotatable center parts are illustrated . 60 the inside outwards. The second bearing blocks are advan
WO2011/ 107395 by the same applicantwas published in tageously arranged in pairs on a tie bars. If the forces do not
2011 and describes a holding device with a modular struc exceed a certain level , the second bearing blocks may also
ture , which can be flexibly adapted to different injection be arranged diagonally with respect to the cross member. For
molding machines. Different types ofholding are described . a good transmission of forces, the second bearing blocks are
EP1119449 by the company Krauss Maffei was first 65 arranged along the tie bar at a distance from one another . In
published in 2001 and shows a two-plate horizontal injection order to achieve a structurally flexible arrangement, at least
molding machine . This has a holding device for a rotatable one second bearing block can be operatively connected from
 US 10,675,800 B2
3 4
one side and / or from above with the cross member via an and above. FIG . 2 shows a center block 17 as used , for
adapter. The cross member is advantageously formed in example , in the injection molding device 1 according to FIG .
multiple parts, so that it can be flexibly adapted to the 1. FIG . 3 shows the center block 17 in a view from the side
circumstances. It may have a central part and one or more and FIG . 4 in a top view .
side parts fixed thereon . In general, the second bearing 5
blocks are fixed to the central part and /or at least on one of DETAILED DESCRIPTION OF THE
the side parts. Advantageously , attention is paid to short load INVENTION
paths . The second bearing blocks serve primarily for the
transmission of the reaction forces which occur due to the The injection molding device 1 has a first mold mounting
drive torque. Weight forces are preferably transmitted via 10 plate 2 and a second mold mounting plate 3 movable relative
the first bearing blocks to the machine bed . thereto . The mold mounting plates 2 , 3 are used for mount
In certain cases, the cross member can also be formed as ing the first and second mold halves of an injection mold
a ( flat) base plate . At least one second bearing block may be (not shown in detail ). The mold mounting plates 2 , 3 are
arranged on or laterally on the base plate . At least one second arranged movably to one another in a first direction (x - di
bearing block may be releasable operatively connected to 15 rection ) along longitudinal guides , here in the form of tie
the cross member. bars 4 of the injection molding device 1. Depending on the
To improve efficiency through weight reduction and area of application and manufacturer of the injection mold
reduction of occurring forces, the invention provides a ing device , other types of longitudinal guides are possible. A
specially designed center block having a main body and at holding device 5 can be recognized between the two mold
least one lower coupling plate fixed thereto. The main body 20 mounting plates 2, 3. This has a lower holding device 6 ,
is thereby manufactured from a material having a lower which in the embodiment shown comprises a lower cross
density than that of the lower coupling plate. For example , member 11, which is arranged movably in the direction of
the main body can be manufactured from aluminum or the tie bar 4 (x -direction ). The lower cross member 11 is
another lightmetal and the at least one coupling plate can be supported in the vertical direction on a rail system 9 on a
manufactured from tool steel. Depending on the design of 25 machine bed (not shown in detail) of the injection molding
the holding device, the center block may also have an upper device 1 via first bearing blocks 8. So that the structure of
coupling plate . Further variants and constructive details can the lower cross member and its support on the guide rails 9
be found in the figures and the accompanying description . In is better visible , the lower front tie bar 4 is shown partially
one embodiment, the at least one coupling plate has at least in section (the course of the sectioned tie bar is represented
one collector line, which operatively connects at least one 30 by a dashed line 10).
connection arranged in the area of the coupling plate (e.g. in The lower holding device 6 and the cross member consist
the form of a self -closing quick coupling) for media such as of a base plate 11 on which a lower rotary system 12 is fixed .
water , compressed air and /or hydraulics with at least one The lower rotary system 12 has lower rotary plate 14 which
media distributor (riser ) extending into the main body. The is rotatable about an axis of rotation 13 arranged vertically
connection can be arranged on the main body or on the 35 here, the rotary plate having rectangular design in the
coupling plate . The center block according to the invention embodiment shown. The lower rotary plate 14 is driven by
and holder described herein can also be used with other a motor 15 , which is arranged here below the base plate 11
retainers or injection molding machines which are not and is thus not visible in the representation shown .
described here. For this reason, the applicant reserves the As can be seen in FIG . 1 , further bearing blocks 16 are
right to further pursue this invention separately in one or 40 mounted on the base plate 11 as needed , which are opera
more divisional applications. tively connected with the lower tie bars 4 in the y -direction
The main body of the center block can be manufactured and serve to at least partially support , the torque generated
by means of a 3D -printing process . This has the advantage by the motor 15 and acting on the base plate 11 against the
that the interior and in particular the media lines can be tie bars 4. This arrangement has the advantage that the guide
flexibly designed and optimally guided . This results in an 45 rails 9 and the first bearing blocks 8 can be largely unloaded
optimized weight distribution and an improved cooling. from the torque of the motor 15. The first bearing blocks 8
Furthermore , the main body may have cavities which con are advantageously arranged as far away from the axis of
tribute to weight reduction . This is not possible in the case rotation 13 and from one another, respectively, ( see distance
of conventionally manufactured main bodies. Alternatively a ) as possible , so that they are more effective due to the
or in addition , targeted reinforcements (not shown ) can be 50 larger lever arm . An advantage of the arrangement shown is
inserted or incorporated . After hardening or tempering of the that the lower rotary plate 14 can be turned more quickly and
printed material, the side surfaces or the connecting surfaces thus the production speed can be reduced .
can be mechanically finished as needed . A centerblock 17 is arranged on the lower rotary plate 14 .
This has side surfaces 18 , which serve to receive pair wise
BRIEF DESCRIPTION OF THE DRAWINGS 55 opposing inner mold halves 34 (see FIGS. 3 and 4 , sche
matically indicated with dashed lines ). These interact with
Aspects of the invention willbe described in greater detail correspondingly formed first and second outer mold halves
with reference to the exemplary embodiments shown in the (not shown ), which are fixed on the first and the second mold
following figures and the description associated therewith . mounting plate 2 , 3. The structure of the center block 17 is
Shown are : 60 explained in detail below .
FIG . 1 an injection molding device in a perspective view ; In the embodiment shown, the holding device 5 addition
FIG . 2 a center block in a perspective view ; ally comprises an upper retaining device 7 in addition to the
FIG . 3 the middle block according to FIG . 2 in a side lower one. On this is fixed an upper cross member 19 having
view ; an upper rotary system 20, as well as an upper rotary plate
FIG . 4 the middle block according to FIG . 2 in a top view . 65 21. The center block 17 is rotatable arranged about the axis
FIG . 1 shows an injection molding device 1 according to of rotation 13 between the two rotary plates 14 , 21. The
the invention in a perspective view obliquely from the front upper cross member 19 has a yoke -shaped design and is
 US 10,675,800 B2
5 6
seated on the two upper tie bars 4. Third bearing blocks 22 , the main body 23. The connections may be mounted on at
which can at least partially engage around the upper tie bars least one of the coupling plates 24 , 27. The coupling plates
4 in an assembled state , are arranged on the ends . The upper 24 , 27 can produce an operative connection between the at
cross member 19 is synchronously movable with the lower least one connection and the media lines extending in the
cross member 7 along the tie bars 4. It is driven by means 5 interior of the main body 23. As media lines 30 are generally
of a linear drive 35 , which consists here of four hydraulic used a plurality ofbores 30 extending in different directions
cylinders. Other, such as electric drives, are possible . in the interior of the main body 23 , the bores having an
In particular through the combination of the special operative connection with one another. At least one of the
design of the lower holding device 6 and the center block 17 coupling plates 24, 27 may take on a collection function for
according to the invention , the holding device 5 shown has 10 a plurality of media lines 30. For this purpose, the at least
the advantage that the upper cross member 19 or the upper one
rotary system 20 , respectively, can in principle be omitted , lines coupling
31 , which
plate 24 , 27 may have one or more collector
operatively connectone or more connections
or flexibly combined thereto as needed . 29 with one ormore media lines 30. In general, the collector
FIG . 2 shows the central block 17 in an exploded view
(disassembly in the z -direction ) at an angle from obliquely 15 coupling
above. FIG . 3 shows the center block 17 in a side view and
lines 31 areplatebores
24, which extend within
27 , respectively the lowerto ortheupper
, transversely axis
FIG . 4 in a top view . In FIG . 4 , hidden lines are shown by of rotation 13. They are fixedly or releasable closed on the
dashed lines. side surface of the corresponding coupling plate 24 , 27, for
The center block 17 has a main body 23 , as well as at least instance with a plug. If needed , the at least one coupling
one lower coupling plate 24. This is fixed on the underside 20 plate 24 , 27 can be formed in multiple parts . For a reduction
of the main body 23 by means of screws 25 and their of weight, the main body 23 may have inner cavities. There
associated blind holes 33, the blind holes being provided exists the possibility, for example, to introduce one or more
with threading. If necessary, feather keys 26 acting in hollows 32 extending in the axial direction , which contribute
circumferential direction with respect to the axis of rotation to weight reduction . If needed , the hollows 32 may be used
13 can be provided for the transmission of forces. 25 for additional purposes , for instance the passage of lines for
The main body 23 is advantageously manufactured from media , etc. If needed , at least one of the coupling plates 24 ,
a material having a lower density than that of the lower 27 may be manufactured from a suitable material by means
coupling plate 24.Good results are obtained when the main of a 3D printing process. Other treatment steps are possible .
body 23 is made from aluminum or another light metal (e.g.
a magnesium alloy ). The mold halves 35 (schematically 30 I claim :
represented by dashed lines ), which are fixed during opera 1. A mold center part ( 17) for use in an injection molding
tion on the side surfaces 18 , are made of a suitable material device ( 1) comprising :
for the respective injection molding manufacturing process. a main body (23 ) and a lower coupling plate ( 24 ) fixed
In general, tool steel is used . Other materials are possible. In thereon , wherein the main body (23) is manufactured
operation , the lower coupling plate 24 establishes the opera- 35 from a material having a lower density than the lower
tive connection between the center block 17 and the lower coupling plate (24).
rotary plate 14 , and is advantageously manufactured from an 2. The mold center part ( 17 ) according to claim 1, wherein
abrasion -resistant and durable material, such as tool steel. the main body (23 ) is manufactured from aluminum and the
Due to the lower density of the material of the main body lower coupling plate ( 24 ) from tool steel .
23 , the weight acting on the holding device 5 is reduced , as 40 3. The mold center part (17 ) according to claim 1, wherein
well as the mass moment of inertia about the axis of rotation the mold center part ( 17 ) includes an upper coupling plate
13. This results in the advantages that the holding device 5 (27).
( see FIG . 1) is unloaded and can be rotated faster in 4. Themold center part ( 17) according to claim 1, wherein
comparison to conventional devices. the main body (23 ) is manufactured by means of a 3D -print
In one variant, the main body 23 is manufactured from a 45 ing process .
suitable material by means of a 3D - printing process. This 5. The mold center part ( 17 ) according to claim 4, wherein
has the advantage that the interior and in particular themedia the main body (23 ) includes cavities to reduce the weight of
lines can be flexibly designed and optimally guided . This the main body (23).
results in an optimized weight distribution and an improved 6. The mold centerpart ( 17 ) according to claim 4 ,wherein
cooling. Furthermore, the main body 23 may have cavities 50 targeted reinforcements are inserted or incorporated in the
which contribute to weight reduction . This is not possible in main body (23 ) .
the case of conventionally manufactured main bodies 23 . 7. The mold center part ( 17 ) according to claim 3, wherein
Alternatively or in addition , targeted reinforcements (not the lower and /or the upper coupling plate (24 , 27 ) is manu
shown ) can be inserted or incorporated . After hardening or factured by means of a 3D -printing process .
tempering of the printed material, the side surfaces or the 55 8. The mold center part (17 ) according to claim 7 , wherein
connecting surfaces can be mechanically finished as needed . the lower and /or the upper coupling plate (24 , 27 ) are
In the embodiment shown , the center block 17 addition partially embedded in recesses (28 ) provided in the bottom
ally has an upper coupling plate 27 , which is mounted on the or top of the main body ( 23 ).
top of the main body 23 by means of screws 25. To improve 9. Themold center part ( 17) according to claim 8 , wherein
the mechanical coupling , feather keys 26 can also be used 60 at least one of the upper and lower coupling plate ( 24 , 27 )
here. Both the lower and the upper coupling plate 24 , 27 can includes at least one collector line (31), which operatively
be arranged partially embedded in recesses 28 provided for connects at least one connection (29 ) with at least onemedia
this purpose in the bottom or the top of the main body 23 . distributor (30 ) extending in the main body (23 ).
In the area of the lower and/or if provided the upper coupling 10. The mold center part ( 17 ) according to claim 9 ,
plate 24 , 27 may comprise one or more connections 29, for 65 wherein the at least one connection (29 ) is arranged on the
example in the form of quick couplings (not shown in detail ) main body (23 ) or the at least one of the upper and lower
for the transfer ofmedia between the holding device 5 and coupling plate ( 24 , 27 ).
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11. The mold center part ( 17) according to claim 10 ,
wherein the at least one connection (29 ) is a self-closing
quick coupling .
12. The mold center part ( 17) according to claim 1 ,
wherein the main body (23 ) is manufactured from magne- 5
sium alloy.
13. The mold center part (17 ) according to claim 1,
wherein the lower coupling plate (24 ) is manufactured from
an abrasion - resistant and durable material.
14. The mold center part (17 ) according to claim 1, 10
wherein at least one hollow ( 32 ) is introduced in the main
body (23 ) wherein the at least one hollow (32 ) extends
axially through the main body (23) along a z -axis .