Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
  • B29C49/02—Combined blow-moulding and manufacture of the preform or the parison
  • B29C49/06—Injection blow-moulding
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
  • B29C49/42—Component parts, details or accessories; Auxiliary operations
  • B29C49/4205—Handling means, e.g. transfer, loading or discharging means
  • B29C49/42069—Means explicitly adapted for transporting blown article
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
  • B29C49/42—Component parts, details or accessories; Auxiliary operations
  • B29C49/4205—Handling means, e.g. transfer, loading or discharging means
  • B29C49/42113—Means for manipulating the objects' position or orientation
  • B29C49/42121—Changing the center-center distance
  • B29C49/42122—Adapting to blow-mould cavity center-center distance
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
  • B29C49/42—Component parts, details or accessories; Auxiliary operations
  • B29C49/48—Moulds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
  • B29C49/42—Component parts, details or accessories; Auxiliary operations
  • B29C49/56—Opening, closing or clamping means
  • B29C49/5601—Mechanically operated, i.e. closing or opening of the mould parts is done by mechanic means
  • B29C49/5602—Mechanically operated, i.e. closing or opening of the mould parts is done by mechanic means using cams
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
  • B29C49/02—Combined blow-moulding and manufacture of the preform or the parison
  • B29C2049/023—Combined blow-moulding and manufacture of the preform or the parison using inherent heat of the preform, i.e. 1 step blow moulding
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
  • B29C49/42—Component parts, details or accessories; Auxiliary operations
  • B29C49/56—Opening, closing or clamping means
  • B29C2049/566—Locking means
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
  • B29C49/42—Component parts, details or accessories; Auxiliary operations
  • B29C49/56—Opening, closing or clamping means
  • B29C49/561—Characterised by speed, e.g. variable opening closing speed
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2101/00—Use of unspecified macromolecular compounds as moulding material
  • B29K2101/12—Thermoplastic materials

Definitions

• the present invention relates to a device for opening and closing a mold for blowing thermoplastic material containers, e.g. PET bottles, on a rotary blow molding machine.
• the blowing or stretch blowing molds used for producing containers from a preform made of thermoplastic material which is preheated generally consist of three parts, for the particular shape of current containers at their base, which is generally concave. Therefore, generally, molds are made which consist of two lateral half molds which shape the body of the container and of a mold bottom to shape the container bottom. Therefore, the lower areas of the two half molds and the upper part of the mold bottom are provided with fixing means, of complementary shape, reciprocally insertable into each other when the mold is in the closed position, to ensure the axial rigidity of the mold in closed position in the presence of the blowing pressure, which generally reaches 40 bar when molding PET containers.
• the two lateral half molds are configured to move relative to each other between an open position and a closed position, under the action of electrically controlled actuating means or via cams.
• the same actuator means are also arranged to control the cyclic opening and closing of the mold bottom. Solutions are particularly widespread which provide for the opening and closing of the two half molds and of the mold bottom by means of cams.
• the maximum angle to be formed upon reaching the maximum opening of the two lateral half molds is closely related to the maximum size of the cross section of the containers to be extracted from the two half molds after molding. This therefore has an influence on the linkage and on the geometry of the cam profile.
• the maximum productivity is measured in containers/h/cavity and is expressed as a function of cycle time
• said cycle time is made up of a step dedicated to the insertion of a preform into the mold and the closing and constraint movement of the mold, and of a step dedicated to the blow molding process, and thus the cycle time also includes a step dedicated to the release, i.e. the opening of the half molds and the extraction of the finished container from the blowing mold. Therefore, the amplitude of the maximum opening angle of the mold has an influence on the duration of the cycle time.
• the maximum size of the containers which can be produced in such machines and the maximum forces which are applied on the various parts of the machine, and in particular the reactions which are transmitted to the cams by the action of the actuator means during the operations are normally defined.
• the mold is designed to open by a first maximum opening angle CM . If containers of smaller sizes are also to be produced on blow molding machines designed to produce containers of a larger format, and thus to open by the first maximum opening angle CM , a maximum opening angle of the mold a2 smaller than a1 would be sufficient for the extraction of the smaller container from the mold.
• a blowing mold for blowing a thermoplastic material container which, according to claim 1 , comprises two half molds hinged to each other and a cyclic opening and closing device adapted to move the two half molds close to and away from each other with an opening angle which ranges from 0 ° in the closed position of the half molds to a maximum opening angle in a position of maximum opening of the two half molds, the cyclic opening and closing device comprising a control shaft adapted to rotate about its own axis Z, a control hub integrally fixed to the control shaft, at least one first connecting rod and at least one second connecting rod, each having a first end hinged to a respective half mold and a second end hinged to the control hub, wherein to a rotation of the control shaft by an angle of rotation ⁇ corresponds the position of maximum opening of the two half molds, wherein the control hub is fixed in a removable manner to one end of the control shaft and is provided with at least three holes for hinging the second ends of said at least one
• An advantage of the mold of the invention is that the opening angle of the two half molds, or lateral half molds, can be made to vary according to the production needs, depending on the size of the container to be blown.
• the maximum value of the opening angle which is formed between the two lateral half molds can take two different amplitudes a1 and a2 as desired, with ⁇ 2 smaller than a1 .
• a smaller maximum opening angle a2 must be reached between the two lateral half molds to make a production of small containers, and this results in an increase in productivity and a decrease in the machine cycle time for the blow molding machine.
• a maximum opening angle a1 greater than a2 is used between the two lateral half molds to make a production of containers with a larger size of the cross section.
• the different arrangement of the holes where the connecting rods can be hinged, advantageously allows to obtain the two different maximum opening angles with equal angle of rotation of the control shaft.
• a lever provided with at least one roller, or bearing, which can slide on an appropriate cam profile.
• the rotation of the lever, and hence of the control shaft, by an angle of rotation ⁇ produces the opening and closing motion of the two half molds by the maximum opening angle.
• the control hub is provided with four holes, or hinge points, to hinge the at least one first connecting rod and the at least one second connecting rod.
• the connection of the two half molds to the control hub, through the connecting rods is preferably effected by means of the two holes, or hinge points, A and B or alternatively in the two holes C and D. Hinging the connecting rods to the holes A and B, respectively, with the rotation of the control shaft by an angle of rotation ⁇ , a maximum opening of the two half molds by an angle a1 is obtained.
• the distance between the holes A and B is different from the distance between the holes C and D, so that hinging the connecting rods to the holes C and D respectively, for an equal angle of rotation ⁇ of the control shaft, an opening of the two mold holders by an angle a2 ⁇ a1 is obtained.
• the mold of the invention is ensured to have greater flexibility to produce container formats with a reduction of the cycle time if containers of smaller size need to be produced.
• the time needed to open and close the molds is optimized according to the format of the containers to be produced, making it possible to exploit the production capacity of the blow molding machine to the maximum possible extent.
• the control hub is provided with three holes, for example, the distance between a first hole and a second hole is appropriately selected different from the distance between the second hole and a third hole.
• One of the three holes e.g. the second hole, is always used to hinge the at least one first connecting rod or the at least one second connecting rod in both maximum opening configurations.
• control hub is fixed to the control shaft so that it can be removed therefrom, allowing the connecting rods to be hinged to different pairs of holes.
• control hub is fixed to an end of the control shaft, so as to facilitate the rapidity of disassembly and assembly.
• the invention also provides a method, according to claim 1 1 , to change the maximum opening configuration of a blowing mold having the aforesaid characteristics, from a first maximum opening configuration to a second maximum opening configuration, comprising the steps of
• step a so as to switch from said first maximum opening configuration, prior to step a), with a first maximum opening angle, to a second maximum opening configuration, upon completion of step b), with a second maximum opening angle different from the first maximum opening angle.
• the invention provides a rotary blow molding machine comprising a plurality of molds having the aforesaid features.
• Fig. 1 shows an axonometric view of the mold of the invention in a first embodiment thereof, connected to a cam track, partially illustrated, and in a first configuration;
• Fig. 2 shows a front view of the mold in Fig.1 ;
• Fig. 3 shows a lateral view of the mold in Fig. 1 ;
• Fig. 4 shows an axonometric view of the mold in Fig. 1 ;
• Fig. 5 shows a plan view of the mold in Fig. 1 ;
• Fig. 6 shows a plan view of the mold in Fig. 1 , in maximum opening position with a maximum opening angle a1 , according to the first configuration
• Fig. 7 shows a plan view of the mold in Fig. 1 in a second configuration, open by a second maximum opening angle a2;
• Fig. 8 shows a first axonometric view of a component of the mold in Fig. 1 ;
• Fig. 9 shows a second axonometric view of a component of the mold in Fig. 8;
• Fig. 10 shows a front view of the mold in Fig. 1 in maximum opening position
• Fig. 1 1 shows a lateral view of the mold in Fig. 10;
• Fig. 12 shows a top view of the mold in Fig. 10,
• Fig. 13 shows an axonometric view of the mold in Fig. 10,
• Fig. 14 shows a front view of the mold in Fig. 7;
• Fig. 15 shows a lateral view of the mold in Fig. 14,
• Fig. 16 shows a top view of the mold in Fig. 14,
• Fig. 17 shows an axonometric view of the mold in Fig. 14,
• Fig. 18 shows an axonometric view of the mold of the invention in a second embodiment thereof
• Figs. 19a and 19b show a plan view and an axonometric view of a bottle of a first format, respectively, which can be produced with a mold of the invention
• Figs. 20a and 20b show a plan view and an axonometric view of a bottle of a second format, respectively, which can be produced with a mold of the invention
• Fig. 21 shows a diagram of the cycle time for the production of a thermoplastic container made with a mold of the invention
• a mold generally indicated with reference numeral 10 is shown. It is a mold adapted to be mounted in a manner known by those skilled in the art on a blow molding machine, not shown in the figures, which typically is a rotary blow molding machine which rotates about its own vertical axis.
• Mold 10 comprises two lateral half molds 1 and 2 and a mold bottom 8, which is particularly useful when the container to be blown has a concave base to allow the extraction of the container upon completion of the blowing cycle.
• the lateral half molds 1 , 2 each comprise a respective external mold holder 3, 4, a shell support 5', 6' and a half shell 5, 6.
• the use of the half shells allows to keep the same mold holders 3 and 4 to produce containers of different formats and sizes, changing only the half shells.
• the shell supports and the shells are made in a single shell block, thus the mold is referred to as monobloc.
• the format change takes place by replacing the shell block, keeping the mold holders.
• the two mold holders 3, 4 are hinged to each other so that they can be opened and closed substantially like a book.
• the mold 10 comprises a control hub 15 which is preferably formed by of a plate shaped portion 22, also referred to as simply plate, from which two raised portions 23, 24 extend in distal direction with respect to each face of the plate 22.
• the raised portions 23, 24 are positioned in an approximately central region of each face of the plate 22.
• a hole 25 with polygonal section, preferably square section with beveled corners, which entirely traverses them.
• the control hub 15 is also provided with circular through holes, mutually identical and obtained in the plate shaped portion 22. Preferably, four circular through holes are provided, indicated with the references A, B, C, D, respectively.
• the holes A, B, C, D are located in predetermined positions and, for a clearer description, the centers of the holes A, B, C, D are considered to be the vertices of a polygon, not shown, which in this case, since four holes are provided, is a quadrilateral.
• the centers of the holes A and B, and of the holes C and D define two non-consecutive sides of said quadrilateral. According to this embodiment, the distance between the centers of the holes A and B is greater than the distance between the centers of the holes C and D.
• Each mold holder 3, 4 is connected to the control hub 15 by means of a system of connecting rods, preferably formed by two pairs of connecting rods; each pair of connecting rods is indicated with reference numerals 14 and 20, respectively, and is connected to a respective mold holder 3, 4.
• a first end of each pair of connecting rods 14, 20 is hinged to the respective mold holder 3, 4 by means of the through hole of the attachment portion 21 .
• the second end of each pair of connecting rods 14, 20 is hinged to the control hub 15 by means of the holes A and B, respectively, defining a first configuration, or operating position, or by means of the holes C and D, respectively, defining a second configuration, or operating position.
• the mold 10 comprises a control shaft 16 apt to be positioned with its axis of rotation Z parallel to the axis of rotation of the blow molding machine.
• the control shaft 16 can rotate about its own axis of rotation Z.
• To a first end 26 of the control shaft 16 is integrally fixed the control shaft
• the cyclic opening and closing movement of the two lateral half molds 1 and 2 and of the mold bottom 8 is produced by a linkage comprising the control shaft 16, which can rotate about the axis Z by an angle ⁇ by means of the passage of the roller 1 1 , which is integral with the lever 13, on the cam track 12.
• the rotation of the lever 13 produces the rotation of the control shaft 16 which in turn enables the control hub 15 to rotate about the axis Z and consequently the opening of the two half molds 1 , 2 takes place by means of the pairs of connecting rods 14, 20.
• the control shaft is rotated by the angle ⁇ , the maximum opening of the mold is obtained.
• the rotation of the control shaft 16 by the angle ⁇ also produces the rotation of the flange 17 in whose cam track 18 slides the cam follower 19 which, in turn, by moving produces alternatively the up and down motion of the mold bottom 8.
• the up and down motion of the mold bottom 8 concurrent, and hence synchronized with the opening and closing motion of the two half molds 1 , 2, is produced by the rotation of the flange 17 integral with the control shaft 16.
• the cam follower 19, traveling through the cam track 18, transforms the rotation of the control shaft 16, and hence of the flange 17, by an angle ⁇ in a vertical motion ⁇ , along a parallel direction to the axis Z.
• control hub 15 can be connected to the pairs of connecting rods 14, 20 in two different ways, defining two maximum opening operating positions or maximum opening configurations.
• the pairs of connecting rods 14, 20 are hinged by means of the holes A and B, respectively.
• the rotation of the control shaft 16 by the angle ⁇ determines the opening of the mold 10 by and angle a1 .
• the angle a1 is, in this configuration, the maximum opening angle of the mold 10 and it is formed between the two half molds 1 , 2 when they are in maximum opening position.
• the opening angle is equal to 0 °.
• the second operating position is preferably obtained rotating the control hub 15 by 180 ° with respect to the axis k-k, or in other words overturning it so as to reverse the faces of the plate 22.
• the pairs of connecting rods 14, 20 are hinged by means of the holes C and D, respectively.
• the rotation of the control shaft 16 by the angle ⁇ which is the same angle ⁇ of the first operating position, determines the opening of the mold by an angle a2.
• the angle a2 is smaller than the angle a1 and in this case it is the maximum opening angle of the mold 10.
• the control hub 15 it is possible to obtain two operating position for which at equal angle ⁇ of rotation of the control shaft 16 in the first operating position the maximum opening angle of the mold 10 is equal to a1 and in the second operating position the maximum opening angle of the mold 10 is equal to a2.
• the two different opening angles are obtained due to the arrangement of the holes A, B, C, D of the control hub 15.
• the angle a1 is greater than the angle a2 in that, as stated previously, the distance between the holes A and B is greater than the distance between the holes C and D.
• the first operating position is used for the production of containers of larger dimensions with respect to the containers which are produced using the second operating position.
• the first operating position is used for containers with cross section S1 greater than the cross section S2 produced with the second operating position.
• the relative motion of the various parts which form the mold 100 can be produced by a servomotor 30.
• the servomotor 30, typically also known as torque motor, sets in rotation the control shaft 16 and through the control hub 15 and the system of connecting rods 14, 20 produces both the opening motion of the two half molds 1 , 2 and the alternative up and down motion of the mold bottom 8.
• Fig. 21 shows a chart illustrating the cycle time advantage afforded by the invention to a blow molding machine.
• the productivity which is measured in containers/h/cavity, is related to the cycle time T according to the expression:
• This cycle time is the sum of:
• T2, Tp2, To2 and T1 , Tp1 , To1 are indicated with reference to a large container and to a small container, respectively.
• a cycle time for the production of a large container, such as for example the bottle shown in Fig. 19, is indicated with the reference T2 in the chart of Figure 21 .
• the maximum opening of the mold 10 is equal to a1 .
• the total cycle time indicated with T1 is shorter than the cycle time T2. Since the time difference to perform the blowing step Tp1 does not differ much from step Tp2, depending in fact mainly on the type of material used to make the container, the cycle time reduction is accomplished by reducing the opening step time To1 and the closing step time Tc1 which are shorter than the times of the corresponding To2 and Tc2 by a value T4 and T3, respectively. Due to these time gains, there is a reduction in the cycle time of the mold equal to T5 whenever it is used to make containers of sizes smaller than those which are the maximum achievable with the mold itself.
• the invention also provides a rotary blow molding machine comprising a plurality of molds as described previously.
• the invention also provides a method for changing the maximum opening configuration of a blowing mold as described previously, comprising the following steps:
• step a so as to switch from said first maximum opening configuration, prior to step a), with a first maximum opening angle, to a second maximum opening configuration, upon completion of step b), with a first maximum opening angle different from the first maximum opening angle.

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• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Mechanical Engineering (AREA)
• Moulds For Moulding Plastics Or The Like (AREA)
• Blow-Moulding Or Thermoforming Of Plastics Or The Like (AREA)

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• 2016
  • 2016-06-14 JP JP2017564134A patent/JP6818697B2/ja active Active
  • 2016-06-14 CN CN201680034292.8A patent/CN108124435B/zh active Active
  • 2016-06-14 RU RU2018100856A patent/RU2707517C2/ru active
  • 2016-06-14 ES ES16747616T patent/ES2779771T3/es active Active
  • 2016-06-14 US US15/736,526 patent/US10377074B2/en active Active
  • 2016-06-14 CA CA2989274A patent/CA2989274C/en active Active
  • 2016-06-14 BR BR112017025725-4A patent/BR112017025725B1/pt active IP Right Grant
  • 2016-06-14 EP EP16747616.7A patent/EP3307517B1/en active Active
  • 2016-06-14 WO PCT/IB2016/053500 patent/WO2016203367A1/en not_active Ceased
  • 2016-06-14 MX MX2017015556A patent/MX2017015556A/es unknown
• 2017
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• 2018
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