An injection blow molding machine for plastic containers with a double-row configuration of seats for preform neck molds

Abstract

An injection blow molding machine configured to allow a simple and safe opening (3) of the blow molds (32) for removing the blown containers, preventing undesired movements of the blown containers also in the event of partial adhesion of the container to one of the two lateral split molds (32). Said machine comprises very simple and inexpensive mold (32) opening (3) systems, also allowing greater flexibility in the opening (3) and closing movements of all the molding components, as they can be independent of one another.

Description

[0001] AN INJECTION BLOW MOLDING MACHINE FOR PLASTIC CONTAINERS WITH A DOUBLE-ROW CONFIGURATION OF SEATS FOR PREFORM NECK MOLDS Field of the invention

[0002] The present invention relates to an injection blow molding machine for plastic containers with a double-row configuration of seats for neck molds of the preforms that will be blown in the same machine to become containers.

[0003] Background art

[0004] Injection blow molding machines for plastic containers are known on the market, including at least one preform injection molding part and one blow molding part for containers, starting from said preforms.

[0005] Some of these machines comprise

[0006] - a fixed base plate;

[0007] - a rotating table, placed underneath and movably supported by said fixed base plate;

[0008] - at least two support apparatuses configured to support each two rows of neck molds and fixed to a lower surface of said rotating table; wherein the rotating table is adapted to intermittently rotate about a vertical axis thereof to sequentially transport each support apparatus at at least a first station for injection molding plastic preforms and a second station for blow molding containers from said preforms.

[0009] Each double-row support apparatus is configured to support two parallel rows of neck molds at a respective through-opening of said rotating table, so that the neck molds are accessible.

[0010] Disadvantageously, in current injection blow molding machines, the downward movement of the mold bottoms occurs before the opening of the lateral split molds. This can cause undesired movements of the blown container in the event of partial adhesion of the container to one of the two lateral split molds, at least partially compromising the quality of the molded part.

[0011] Furthermore, current injection blow molding machines have highly complex mechanisms for opening the split molds and mold bottoms.

[0012] An example of a well-known injection blow molding machine is disclosed in document US20120294974A1 . Thus, the need is felt to develop an innovative solution which allows overcoming the aforesaid drawbacks.

[0013] Summary of the invention

[0014] It is the primary object of the present invention to develop an injection blow molding machine, which allows a simple and safe opening of the blow molds for removing the blown containers, avoiding undesired movements of the blown containers also in the case of partial adhesion of the container to one of the two lateral split molds.

[0015] It is another object of the invention to develop an injection blow molding machine with very simple and less expensive mold opening systems.

[0016] It is a further object of the invention to develop an injection blow molding machine, which allows greater flexibility in the opening and closing movements of all the molding components with respect to the prior art so said movements can be independent of one another.

[0017] It is another object of the invention to develop a method for operating the aforesaid injection blow molding machine efficiently, in particular, after the blowing of the containers.

[0018] Thus, the present invention aims to achieve at least one of the aforesaid objects by developing an injection blow molding machine for plastic containers, at least including one injection molding station for preforms and a blow molding station for containers, the machine further comprising

[0019] - a rotating table provided, along the periphery thereof, with at least two doublerow support apparatuses, configured to support each two parallel rows of neck molds, and adapted to intermittently rotate so that each of said at least two doublerow support apparatuses moves sequentially from one molding station to the other one at the same time; wherein each double-row support apparatus comprises two pairs of longitudinal plates, each pair of plates being adjacent to the other pair of plates along a longitudinal axis X and defining a respective row of seats for respective neck molds; wherein said blow molding station is a double-row molding station provided with two parallel rows of container molds adapted to lie, along respective parallel vertical planes, at said two parallel rows of neck molds of a double-row support apparatus; wherein said double-row molding station comprises a fixed central part and two movable side parts, which, in the closed position, define said two parallel rows of molds; wherein a first movable side part is arranged at a first side of said fixed central part, and a second movable side part is arranged at a second side of said fixed central part, opposite the first side; wherein each movable side part is movable along a direction transverse to said longitudinal axis X and comprises a respective row of mold bottoms for molding the bottom of a row of containers; wherein there are provided at said blow molding station:

[0020] - first movement means for synchronously and equally making a first movement at a first speed, of the two pairs of plates, mutually distancing them or bringing them together along a direction transverse to said longitudinal axis X;

[0021] - second movement means for synchronously and equally making a second movement, at a second speed greater than said first speed, of each movable side part with respect to the fixed central part along said transverse direction, mutually distancing them or bringing them together;

[0022] - third movement means for synchronously and equally making a third movement, at said first speed, of the two rows of mold bottoms with respect to the fixed central part along said transverse direction, mutually distancing them or bringing them together;

[0023] - synchronization means for synchronizing, after the blowing of the containers in the double-row molding station, said first movement, said second movement, and said third movement, whereby during a distancing between the two pairs of plates, and thus between the two rows of neck molds, and a simultaneous distancing between the two rows of mold bottoms, the longitudinal axis of the blown containers remains vertical during a distancing of the movable side parts with respect to the fixed central part.

[0024] A second aspect of the present invention relates to a method for operating the aforesaid injection blow molding machine for plastic containers, wherein, after the blowing of the containers in the double-row molding station, in order to remove said containers from said double-row molding station, the following steps are provided:

[0025] - synchronously and equally making a first movement, at a first speed, of the two pairs of plates, mutually distancing them along a direction transverse to said longitudinal axis X;

[0026] - synchronously and equally making a second movement, at a second speed greater than said first speed, of each movable side part with respect to the fixed central part along said transverse direction, mutually distancing them for an opening of the two parallel rows of container molds;

[0027] - synchronously and equally making a third movement, at said first speed, of the two rows of mold bottoms with respect to the fixed central part along said transverse direction, mutually distancing them; wherein a synchronization is provided for said first movement, second movement, and third movement, whereby, during the movement of the two pairs of plates, and thus of the two rows of neck molds, and the simultaneous movement of the two rows of mold bottoms, the longitudinal axis of the blown containers remains vertical during said opening.

[0028] Other advantages of the solution of the present invention include:

[0029] - compactness and very limited dimensions;

[0030] - high mechanical precision and limited clearances;

[0031] - the actuators integrally mounted on a fixed base plate, which also accommodates the rotating table provided with the double-row support apparatuses, each supporting two rows of neck molds, make the movement of the pitch change independent from the movement of other machine components (e.g., the blow press).

[0032] The dependent claims describe preferred embodiments of the invention.

[0033] Brief description of the Figures

[0034] Further features and advantages of the invention will become more apparent in the light of the detailed description of preferred, but non-exclusive embodiments of a technical solution partially shown, by way of a non-limiting example, with reference to the accompanying drawing tables, in which: Figure 1 represents a top perspective view of a rotating table provided with double-row support apparatuses, associated with a fixed base plate of a molding machine;

[0035] Figure 2 represents a bottom perspective view of the rotating table in Figure 1 ;

[0036] Figure 3 represents a partial bottom view of the rotating table in Figure 1 in a first operating position;

[0037] Figure 4 represents a partial bottom view of the rotating table in Figure 1 in a second operating position;

[0038] Figure 5 represents an enlargement of a first part of the view in Figure 3;

[0039] Figure 6 represents an enlargement of a first part of the view in Figure 4;

[0040] Figure 7 represents an enlargement of a second part of the view in Figure 3;

[0041] Figure 8 represents an enlargement of a second part of the view in Figure 4;

[0042] Figure 9 represents a side view of the blow molding station in a first operating position;

[0043] Figure 10 represents a side view of the blow molding station in a second operating position;

[0044] Figure 11 represents a side view of the blow molding station in a third operating position;

[0045] Figure 12 represents a perspective view of two rows of blown containers removed from said blow molding station;

[0046] Figure 13 represents a sectional side view of said blow molding station;

[0047] Figure 14 represents an enlarged side view of Figure 9;

[0048] Figure 15 represents an enlarged side view of Figure 10;

[0049] Figures 16a to 16f represent a bottom view of the rotating table in Figure 1 in six different operating positions;

[0050] Figure 17 shows a diagram of the synchronization of various actuators of the machine of the invention.

[0051] The same reference numerals in the figures identify the same elements or components.

[0052] Detailed description of embodiments of the invention With reference to the Figures, parts of an injection blow molding machine are shown for producing containers made of a thermoplastic material, such as PET, PEN or other suitable material, as well as mixtures thereof.

[0053] The injection blow molding machine for plastic containers, only partially shown, comprises (Figures 1-4):

[0054] - a fixed base plate 1 ;

[0055] - a rotating table 2, placed underneath and movably supported by the fixed base plate 1 , and provided along the periphery thereof with at least two through- openings 3 (Figure 1 );

[0056] - at least two double-row support apparatuses 5 configured to each support two rows of neck molds 32 of a plastic container, the support apparatuses 5 being removably fastened to the lower surface 17 of the rotating table 2 (Figure 2).

[0057] For simplicity, figures 2 and 5-6 show only one neck mold 32 in each of the two rows of neck mold seats 34.

[0058] In particular, each double-row support apparatus 5 is fastened at a respective through-opening 3 of the rotating table 2.

[0059] As better illustrated in Figures 3-6, the rotating table 2 can be provided, on the lower surface 17 thereof, at two opposite ends of each through-opening 3, with respective lateral guides 4 configured to laterally insert or remove, parallel to said lower surface 17, a corresponding double-row support apparatus 5.

[0060] Each double-row support apparatus 5 comprises two pairs of longitudinal split plates 6, 6', each pair of plates 6, 6' being adjacent to the other pair of plates 6, 6' along a longitudinal axis X. In turn, each pair of plates comprises two plates 6, 6' adjacent to each other along a respective longitudinal axis X' and separable from each other transversely to said longitudinal axis X (Figure 7), and kept adjacent in a normally closed state, for example, by elastic means (not shown), defining a respective row of seats for respective neck molds.

[0061] In the normally closed state, the position of the two pairs of plates 6, 6' is shown in Figure 3. When the double-row support apparatus 5 moves from the normally closed position to an open position of the plates 6, 6' (not shown), initially one pair of plates 6, 6' is distanced from the other pair adjacent thereto transversely to said longitudinal axis X (such as, for example, in Figure 16e), and subsequently, the plates 6, 6' of each pair are mutually distanced, again transversely to said longitudinal axis X.

[0062] Therefore, if a force is not applied to mutually separate or open the plates 6, 6' of each pair transversely, preferably orthogonally, to said longitudinal axis X, the plates 6, 6' of each pair are adjacent to each other, and thus in a closed state. For example, this separating force can be applied to the respective two ends of each pair of plates 6, 6' by means of wedges, which are inserted between two rollers (not shown), one roller for each plate end.

[0063] The elastic means, not described herein as they are known per se, comprise springs arranged on the outer longitudinal edges of the plates 6, 6' of the two pairs of plates, said springs preferably being arranged inside respective recesses of said outer longitudinal edges.

[0064] The two plates 6, 6' of each pair of plates, preferably rectangular in shape, are provided, along an inner longitudinal edge, with a respective plurality of substantially semicircular lateral recesses, positioned so that, when the plates 6, 6' of a pair of plates are in the normally closed state, the lateral recesses of the plates 6, 6' of the pair of plates are adjacent to each other in pairs, defining corresponding seats 34, e.g., substantially circular, to accommodate a respective neck mold 32 (Figure 5).

[0065] The neck molds 32 each comprise a pair of split molds, each split mold being accommodated in a lateral recess of a respective plate 6, 6', whereby when the plates 6, 6' of each pair of plates are in the normally closed state, the two split molds are adjacent.

[0066] In particular, at the two opposite ends of each through-opening 3 (Figures 1-2), a pair of lateral guides 4, transverse to the longitudinal axis X, can be provided and fastened to the lower surface 17 of the rotating table 2; each lateral guide 4 being adapted to support, from the bottom, by means of a shoulder made thereon, a respective end of the assembly of the two pairs of longitudinal plates 6, 6' of the double-row support apparatus 5.

[0067] Preferably, the lateral guides 4 are provided with a respective locking system (not shown) for locking or unlocking the two pairs of plates 6, 6’ to / from the pair of lateral guides 4, so that in an unlocked position, the two pairs of plates 6, 6' can be removed transversely to the longitudinal axis X by sliding on the lateral guides 4, in particular by sliding on the horizontal surface of the shoulder provided on said lateral guides 4.

[0068] The plates 6, 6’ of each pair of plates, which are equal to each other, are preferably in the shape of a rectangular parallelepiped, with the longitudinal extension (along the axis X) being greater than both the width and the thickness of the plate.

[0069] The rotating table 2, for example in the shape of a disc, is adapted to intermittently rotate, in order to sequentially move, at each radial rotation pitch, each of the at least two through-openings 3, and thus each double-row support apparatus 5, from one work station to another at the same time.

[0070] In the case of two double-row support apparatuses 5, the rotating table 2 rotates intermittently, to move a first support apparatus 5 from a plastic preform injection molding station to a blow molding station for containers, starting from said preforms, and simultaneously move a second support apparatus 5 from said blow molding station to said injection molding station.

[0071] Four double-row support apparatuses 5 are provided in the example in Figures 1- 2. In this case, the rotating table 2 rotates intermittently to sequentially move each of the four through-openings 3, and thus each of the four double-row support apparatuses 5, from one workstation to another at the same time.

[0072] In particular, each double-row support apparatus 5 is moved in sequence from a first preform injection molding station to a second preform temperature adjustment station; from said second station to a third blow molding station for containers; from said third station to a fourth container unloading station; and from said fourth station to said first station. In this case, the double-row support apparatuses 5, in particular the centers of gravity of said apparatuses, are arranged on the rotating table 2 at an angular distance of 90° from each other, corresponding to the radial rotation pitch from one station to the other one.

[0073] The first preform injection molding station, the second preform temperature adjustment station and the fourth container ejection station are not described here in detail because they are of known type. In the machine of the invention, the third work station, i.e. the blow molding station, is a double-row molding station provided with two parallel rows of container molds adapted to lie, along respective parallel vertical planes, at the two parallel rows of neck molds 32 of a corresponding double-row support apparatus 5.

[0074] This double-row molding station comprises a fixed central part 14 and two movable side parts 15, 15' (Figures 9-11 and 14-15) which, in the closed position, define the two parallel rows of container body molds.

[0075] A first movable side part 15 is arranged at a first side of the fixed central part 14, and a second movable side part 15' is arranged at a second side of said fixed central part 14, opposite the first side. Each movable side part 15, 15' is movable along a direction transverse to the longitudinal axis X, which is the same transverse direction along which the pairs of plates 6, 6' move.

[0076] Advantageously, each movable side part 15, 15' also comprises the respective row of mold bottoms 16, 16' for molding the bottom of a row of containers. Therefore, each row of mold bottoms 16, 16' also moves, preferably exclusively, along said direction transverse to the longitudinal axis X. In particular, a downward movement of the mold bottoms is not provided before the opening of the lateral split molds of each row of container molds. This prevents undesired movements of the blown container in the case of partial adhesion of the container to one of the two lateral split molds, thus not compromising the quality of the molded part.

[0077] Furthermore, advantageously, at the blow molding station there are provided:

[0078] - first movement means for synchronously and equally making a first movement, at a first speed, of the two pairs of plates 6, 6', mutually distancing them, or bringing them together along said direction transverse to the longitudinal axis X;

[0079] - second movement means for synchronously and equally making a second movement, at a second speed greater than said first speed, of each movable side part 15, 15' with respect to the fixed central part 14 along said transverse direction, mutually distancing them or bringing them together;

[0080] - third movement means for synchronously and equally making a third movement, at said first speed, of the two rows of mold bottoms 16, 16' with respect to the fixed central part 14 along said transverse direction, mutually distancing them or bringing them together; - synchronization means 30 for synchronizing, after the blowing of the containers in the double-row molding station, the first movement, the second movement and the third movement, whereby during a distancing between the two pairs of plates 6, 6', and thus between the two rows of neck molds, and a simultaneous distancing between the two rows of mold bottoms 16, 16', the longitudinal axis of the blown containers remains vertical during a distancing of the movable side parts 15, 15' with respect to the fixed central part 14.

[0081] In this way, by virtue of the synchronous distancing, and at the same speed, both of the two pairs of plates 6, 6' from each other and of the rows of mold bottoms 16, 16' from each other, the gripping of the containers by the neck by virtue of the respective neck molds and the support of the bottom of the containers on the respective mold bottom allow the containers to keep the longitudinal axis thereof vertical.

[0082] In a preferred variant, the synchronization means 30 are configured so that a first distancing stroke C of the movable side parts 15, 15' from each other is twice a second distancing stroke P2-P1 both of the two pairs of plates 6, 6' from each other and of the two rows of mold bottoms 16, 16' from each other.

[0083] In other words, the distancing stroke C / 2 of each of the movable side parts 15, 15' with respect to the fixed central part 14 (Figure 10) is twice the distancing stroke D, equal to (P2-P1 ) / 2, of each of the two pairs of plates 6, 6' and of each of the two rows of mold bottoms 16, 16' with respect to said fixed central part (Figures 14- 15).

[0084] In particular, the aforesaid synchronization means 30 are configured so that said first distancing stroke C and said second distancing stroke P2-P1 are performed simultaneously in the same interval of time. Thus, in the mold opening step, the aforesaid second speed of each movable side part 15, 15' is twice the aforesaid first speed of the two pairs of plates 6, 6' and of the two rows of mold bottoms 16, 16'.

[0085] As schematically illustrated in Figures 9-11 , the removal of the containers, e.g., bottles, from the mold occurs by moving the two pairs of plates 6, 6', and thus the two rows of bottles, from a molding inter-row pitch P1 (Figure 9 and 14) to a removal inter-row pitch P2 (Figure 10 and 15), whereby the variation in the inter- row pitch P2-P1 , equal to 2D, is equal to half the total opening stroke C of the blow mold.

[0086] In the embodiment shown in Figures 3-8, the aforesaid first movement means comprise a system of actuators 8, 9, 10 fixed on the fixed base plate 1 at each double-row support apparatus 5.

[0087] Each system of actuators 8, 9, 10 comprises:

[0088] - a first actuator 8 and a second actuator 9 provided with respective stems 8', 9', fixed on the fixed base plate 1 in a radially external position to the rotating table 2 and arranged at two opposite ends of the double-row support apparatus 5, e.g., present at the blow molding station, for mutually distancing the two pairs of plates 6, 6';

[0089] - and a third actuator 10 provided with a respective stem 10', fixed on the fixed base plate 1 in a radially internal position to the rotating table 2 and arranged at a central area of said double-row support apparatus 5, for bringing the two pairs of plates 6, 6' together.

[0090] The rotating table 2 preferably has a central hole 26, coaxial to the rotation axis of said rotating table, configured to receive the transmission of the rotational movement for the rotating table 2.

[0091] In a preferred variant (Figures 3-6), the aforesaid first movement means further comprise, on the rotating table 2, at each of said two opposite ends of each double-row support apparatus 5, a movable rack system 11 , 12 with an interposed fixed gear wheel 13.

[0092] The movable double-rack system 11 , 12 is operable by the respective stems 8', 9' of the first actuator 8 and the second actuator 9 for synchronously and equally mutually distancing the two pairs of plates 6, 6' (from Figure 5 to Figure 6), each movable rack 11 , 12 being connected to a respective pair of plates 6, 6' of said double-row support apparatus 5, e.g., by means of a respective connecting element 27, 28, such as a respective plate.

[0093] Said movable double-rack system 11 , 12 is operable, instead, by the stem 10' of the third actuator 10 for synchronously and equally bringing together the two pairs of plates 6, 6' (from Figure 8 to Figure 7), exerting a thrust on the pair of plates 6, 6' proximal thereto. In particular, at each of said two opposite ends of each double-row support apparatus 5, each movable double-rack system 11 , 12 can comprise:

[0094] - a first movable rack 11 sliding on the rotating table 2 transversely to the longitudinal axis X and connected to the first pair of plates 6, 6' of the double-row support apparatus 5, e.g., by means of the connecting plate 27;

[0095] - a second movable rack 12 sliding on the rotating table 2 transversely to said longitudinal axis X and connected to the second pair of plates 6, 6' of said doublerow support apparatus 5, e.g., by means of the connecting plate 28;

[0096] - a gear wheel 13 with a fixed rotation axis on the rotating table 2, arranged between the first movable rack 11 and the second movable rack 12 and engaging with these latter; whereby, in order to synchronously distance the two pairs of plates 6, 6' from each other, the first actuator 8 and the second actuator 9 actuate a sliding of the first movable racks 11 , and thus of the first pair of plates 6, 6’ by means of the respective stems 8', 9', along a first direction, simultaneously causing a sliding of the second movable racks 12, and thus of the second pair of plates 6, 6', by virtue of the gear wheel 13, along a second direction opposite the first direction; while, in order to synchronously mutually bring the two pairs of plates 6, 6' towards each other, the third actuator 10 actuates a sliding of the first pair of plates 6, 6', and thus of the first movable racks 11 , by means of the respective stem 10’, along said second direction, simultaneously producing, again by virtue of the gear wheel 13, a sliding of the second movable racks 12, and thus of the second pair of plates 6, 6', along said first direction.

[0097] Since the rotating table 2 must rotate in order to allow the support apparatuses 5 to pass from one work station to the other one, the stems 8', 9' are not connected to the respective first movable racks 11 but simply, during the extension thereof in order to mutually distance the two pairs of plates 6, 6', one end thereof abuts and presses against a corresponding abutment surface 33 provided on a proximal end of the first movable racks 11 , causing them to slide.

[0098] Similarly, the stem 10' is not connected to the first pair of plates 6, 6' but simply, in order to mutually distance the two pairs of plates 6, 6', an abutment surface 31 provided at the central area of a plate 6 of said first pair of plates 6, 6' presses on a corresponding end of the stem 10', causing it to retract (from Figure 7 to Figure 8).

[0099] Conversely, in order to bring the two pairs of plates 6, 6' together, said end of the stem 10' extends and presses against the abutment surface 31 and, consequently, the abutment surfaces 33 press against the corresponding ends of the stems 8', 9', causing them to retract.

[0100] In the embodiment shown in Figures 14-15, which can be combined with the embodiment shown in Figures 1-11 , the aforesaid second movement means comprise at least one actuator 20, e.g. two actuators 20, for actuating each movable side part 15, 15' of the molding station, while the aforesaid third movement means comprise a pair of mechanisms 21 .

[0101] Each mechanism 21 of said pair connects a row of mold bottoms 16, 16' to a respective movable side part 15, 15' so that said row of mold bottoms 16, 16' moves with the first speed, which is less than the second speed, preferably equal to half the second speed.

[0102] In a preferred variant, each mechanism 21 of said pair comprises a double-rack system 22, 23 with an interposed movable gear wheel 24.

[0103] Preferably, a movable rack 22 is integrally fastened to the respective movable side part 15, 15'; a fixed rack 23 is integrally fastened to a base of the blow molding station; and the movable gear wheel 24 is integrally fastened to a movable support plate 25 supporting the respective row of mold bottoms 16, 16'.

[0104] Suitable guides are provided to make the movable support plate 25 slide.

[0105] The movement of each movable support plate 25, and thus of the relative mold bottoms, is connected to the movement of the corresponding movable side part 15, 15' of the blow press by means of a respective mechanism 21. Since the movable gear wheels 24 are fixed to the respective movable support plate 25, the motion speed of the latter is half the speed of the movable rack 22 fixed to the respective movable side part 15, 15'.

[0106] Thus, in this embodiment, the synchronization means 30, besides including management software for actuators 8, 9, 10 and actuators 20 (Figure 17), also comprise the aforesaid mechanisms 21 .

[0107] A method according to the invention is described below for operating the aforesaid injection blow molding machine for plastic containers, in which, after the blowing of the containers in the double-row molding station, the following steps are provided for removing the blown containers from said double-row molding station:

[0108] - synchronously and equally making a first movement, at a first speed, of the two pairs of plates 6, 6', mutually distancing them along a direction transverse to said longitudinal axis X;

[0109] - synchronously and equally making a second movement, at a second speed greater than said first speed, of each movable side part 15, 15' with respect to the fixed central part 14 along said transverse direction, mutually distancing them for an opening of the two parallel rows of container molds;

[0110] - synchronously and equally making a third movement, at said first speed, of the two rows of mold bottoms 16, 16' with respect to the fixed central part 14 along said transverse direction, mutually distancing them; wherein a synchronization of said first movement, second movement and third movement is provided, whereby, during the movement of the two pairs of plates 6, 6', and thus of the two rows of neck molds, and the simultaneous movement of the two rows of mold bottoms 16, 16', the longitudinal axis of the blown containers remains vertical during said opening.

[0111] Preferably, the distancing stroke C of the movable side parts 15, 15' from each other is twice the distancing stroke P2-P1 of both the two pairs of plates 6, 6' from each other and the two rows of mold bottoms 16, 16' from each other; and said distancing stroke C and said distancing stroke P2-P1 are performed in a same period of time.

[0112] Figures 16a to 16f show an example of the steps of the container production process, using a machine according to the invention, at the blow molding station.

[0113] Figure 16a shows an operating position of the rotating table 2 with a support apparatus 5, supporting two parallel rows of preforms by means of the two rows of neck molds, at the blow molding station. In this operating position, the inter-row pitch is equal to P1 at a time to.

[0114] The first movement means are positioned so that the stems 8', 9' of the first actuator 8 and the second actuator 9, respectively, are extended until they contact the abutment surfaces 33 of the first movable racks 11 , while the stem 10' of the third actuator 10 is extended until it contacts the abutment surface 31 provided at the central area of a plate 6 of said first pair of plates 6, 6'.

[0115] Figure 16b shows an operating position, in which the inter-row pitch changes from P1 to P3, greater than P1 , at a time t1 for the entry of the two rows of preforms inside the two parallel rows of the respective container molds, which is carried out by lowering the rotating table 2, and thus the support apparatus 5.

[0116] The first actuator 8 and the second actuator 9 press on the respective abutment surfaces 33, by means of an extension of the respective stems 8’, 9’, causing a sliding of the first movable racks 11 , and thus of the first pair of plates 6, 6', equal to (P3-P1) / 2 along a first direction, simultaneously producing an equal sliding of the second movable racks 12, and thus of the second pair of plates 6, 6', along a second direction opposite the first direction. This produces a pressure of the abutment surface 31 on the stem 10', causing it to retract.

[0117] The inter-row pitch P3 can be about 8-12 mm greater than the inter-row pitch P1 , e.g., 10 mm greater than P1. This change in inter-row pitch becomes necessary when there are risks of collision between the body of the preforms, which are lowered for entering the molds, and the central fixed part 14 of said molds.

[0118] Figure 16c shows an operating position, in which the inter-row pitch returns from P3 to P1 at a time t2 for the start of the blow molding step, with closed container molds, concluding with the formation of the blown containers.

[0119] The third actuator 10 presses on the abutment surface 31 , by means of an extension of the respective stem 10’, causing a sliding of the first pair of plates 6, 6’, and thus of the first movable racks 11 , equal to (P3-P1 ) / 2 along said second direction, and simultaneously producing an equal sliding of the second movable racks 12 and thus of the second pair of plates 6, 6’, along said first direction. This produces a pressure of the abutment surfaces 33 on the respective stems 8’, 9’, causing them to retract.

[0120] Figure 16d shows an operating position in which the inter-row pitch shifts from P1 to P2 at a time t3 for the removal of the blown containers from above, by virtue of the lifting of the rotating table 2 (Figure 11 ), and thus of the double-row support apparatus 5.

[0121] The first actuator 8 and the second actuator 9, by means of an extension of the respective stems 8’, 9’, press on the respective abutment surfaces 33, causing a sliding of the first movable racks 11 , and thus of the first pair of plates 6, 6’, equal to (P2-P1) / 2 along a first direction, simultaneously producing an equal sliding of the second movable racks 12, and thus of the second pair of plates 6, 6’, along the second direction opposite to the first direction. This produces a pressure of the abutment surface 31 on the stem 10', causing it to retract.

[0122] Preferably, the distancing stroke C of the movable side parts 15, 15’ from each other is twice the distancing stroke P2-P1 of both the two pairs of plates 6, 6’ from each other and the two rows of mold bottoms 16, 16’ from each other; said distancing stroke C and said distancing stroke P2-P1 being performed in a same period of time.

[0123] The inter-row pitch P2 can be about 100-120 mm greater than the inter-row pitch P1 , e.g., 110 mm greater than P1.

[0124] Figure 16e shows an operating position, in which, after the removal of the blown containers from the container molds, the inter-row pitch changes from P2 to P4, with P4 being between P2 and P1 , preferably between P2 and P3, at a time t4.

[0125] This change in inter-row pitch is carried out to prepare the blown containers for a container unloading pitch, said unloading being carried out in the subsequent unloading station, after a 90° rotation of the rotating table 2 if four workstations are present in the machine of the invention.

[0126] In this case, the third actuator 10 presses on the abutment surface 31 by means of an extension of the respective stem 10’, causing a sliding of the first pair of plates 6, 6’, and thus of the first movable racks 11 , equal to (P4-P2) / 2 along said second direction, and simultaneously producing an equal sliding of the second movable racks 12 and thus of the second pair of plates 6, 6’, along said first direction. This produces a pressure of the abutment surfaces 33 on the respective stems 8’, 9’, causing them to retract.

[0127] The inter-row pitch P4 can be about 40-60 mm greater than the inter-row pitch P1 , e.g., 50 mm greater than P1 .

[0128] Lastly, Figure 16f shows the same operating position as Figure 16e at a successive instant t5, in which, after the adjustment of the inter-row pitch for the subsequent unloading of the blown containers, the actuators 8, 9, and 10 retract the respective stems 8’, 9’, and 10’ into a position outside machine encumbrance so as not to obstruct the subsequent rotation of the rotating table 2 for the passage of the two rows of blown containers from the blow molding station to the unloading station.

Claims

CLAIMS1. An injection blow molding machine for plastic containers, at least including one preform injection molding station and one container blow molding station, the machine further comprising- a rotating table (2) provided along the periphery thereof with at least two doublerow support apparatuses (5), configured to each support two parallel rows of neck molds, and adapted to intermittently rotate so that each of said at least two doublerow support apparatuses (5) sequentially moves from one molding station to the other one at the same time; wherein each double-row support apparatus (5) comprises two pairs of longitudinal plates (6, 6’), each pair of plates (6, 6’) being adjacent to the other pair of plates (6, 6’) along a longitudinal axis (X) and defining a respective row of seats for respective neck molds; wherein said blow molding station is a double-row molding station provided with two parallel rows of container molds adapted to lie, along respective parallel vertical planes, at said two parallel rows of neck molds of a double-row support apparatus (5); wherein said double-row molding station comprises a fixed central part (14) and two movable side parts (15, 15’) which, in closed position, define said two parallel rows of molds; wherein a first movable side part (15) is arranged at a first side of said fixed central part (14) and a second movable side part (15’) is arranged at a second side of said fixed central part (14), opposite to the first side; wherein each movable side part (15, 15’) is movable along a direction transverse to said longitudinal axis (X) and comprises a respective row of mold bottoms (16, 16’) for molding the bottom of a row of containers; wherein there are provided at said blow molding station- first movement means for producing a first movement in a manner synchronous and equal, at a first speed, of the two pairs of plates (6, 6’), mutually distancing them or bringing them together along a direction transverse to said longitudinal axis (X); characterized by the fact that, at said blow molding station, there are furtherprovided- second movement means for producing a second movement in a manner synchronous and equal, at a second speed greater than said first speed, of each movable side part (15, 15’) with respect to the fixed central part (14) along said transverse direction, mutually distancing them or bringing them together;- third movement means for producing a third movement in a manner synchronous and equal, at said first speed, of the two rows of mold bottoms (16, 16’) with respect to the fixed central part (14) along said transverse direction, mutually distancing them or bringing them together;- synchronization means for synchronizing, after the blowing of the containers in the double-row molding station, said first movement, said second movement and said third movement, whereby during a distancing between the two pairs of plates (6, 6’), and thus between the two rows of neck molds, and a simultaneous distancing between the two rows of mold bottoms (16, 16’), the longitudinal axis of the blown containers remains vertical during a distancing of the movable side parts (15, 15’) with respect to the fixed central part (14).

2. A machine according to claim 1 , wherein a first distancing stroke (C) of the movable side parts (15, 15’) from each other is twice a second distancing stroke (P2-P1 ) both of the two pairs of plates (6, 6’) from each other and of the two rows of mold bottoms (16, 16’) from each other; wherein said synchronization means are configured so that said first distancing stroke (C) and said second distancing stroke (P2-P1 ) are performed in a same period of time.

3. A machine according to claim 1 or 2, wherein said second movement means comprise at least one actuator (20) connected to each movable side part (15, 15’), and wherein said third movement means comprise a pair of mechanisms (21 ), each mechanism (21 ) of said pair connecting a row of mold bottoms (16, 16’) to a respective movable side part (15, 15’) so that said row of mold bottoms (16, 16’) moves with the first speed lower, preferably equal to half, the second speed.

4. A machine according to claim 3, wherein each mechanism (21) of said pair comprises a double rack system (22, 23) with a movable gear wheel (24) interposed; preferably wherein- a movable rack (22) is integrally fastened to the respective movable side part (15, 15’);- a fixed rack (23) is integrally fastened to a base of the blow molding station;- the movable gear wheel (24) is integrally fastened to a movable support plate (25) which supports the respective row of mold bottoms (16, 16’).

5. A machine according to any one of the preceding claims, wherein there is provided a fixed base plate (1 ), said rotating table (2) being placed underneath and movably supported by said fixed base plate (1 ); and wherein said first movement means comprise a system of actuators (8, 9, 10) fastened to said fixed base plate (1 ) at each double-row support apparatus (5).

6. A machine according to claim 5, wherein said actuator system (8, 9, 10) comprises- a first actuator (8) and a second actuator (9) provided with a respective stem (8’, 9’), fastened to the fixed base plate (1 ) in a radially external position with respect to the rotating table (2) and arranged at two opposite ends of the corresponding double-row support apparatus (5), for mutually distancing the two pairs of plates (6, 6’);- and a third actuator (10) provided with a respective stem (10’), fastened to the fixed base plate (1) in a radially internal position with respect to said rotating table (2) and arranged at a central area of said double-row support apparatus (5), for mutually bringing the two pairs of plates (6, 6’) together.

7. A machine according to claim 6, wherein said first movement means further comprise, on the rotating table (2), at each of said two opposite ends of the double-row support apparatus (5), a movable double-rack system (11 , 12) with a fixed gear wheel (13) interposed, wherein said movable double-rack system (11 , 12) is operable by the respective stem (8’, 9’) of the first actuator (8) and the second actuator (9) for synchronously and equally distancing the two pairs of plates (6, 6’), each movable rack (11 , 12) of said movable double-rack system being connected to a respective pair of plates (6, 6’) of said double-row support apparatus (5); and wherein said movable double-rack system (11 , 12) is operable by the stem (10’) of the third actuator (10) for synchronously and equally bringing the two pairsof plates (6, 6’) together, by exerting a thrust on the pair of plates (6, 6’) proximal thereto.

8. A machine according to claim 7, wherein, at each of said two opposite ends of the double-row support apparatus (5), each movable double-rack system (11 , 12) comprises- a first movable rack (11 ) sliding transversely to said longitudinal axis (X) on said rotating table (2) and connected to a first pair of plates (6, 6’) of said double-row support apparatus (5);- a second movable rack (12) sliding transversely to said longitudinal axis (X) on said rotating table (2) and connected to a second pair of plates (6, 6’) of said double-row support apparatus (5);- a gear wheel (13) with a fixed rotation axis on said rotating table (2), arranged between the first movable rack (11 ) and the second movable rack (12) and engaging with these latter; whereby, in order to synchronously mutually distance the two pairs of plates (6, 6’), the first actuator (8) and the second actuator (9), by means of the respective stem (8’, 9’), actuate a sliding of the first movable racks (11 ), and thus of the first pair of plates (6, 6’), along a first direction simultaneously producing a sliding of the second movable racks (12), and thus of the second pair of plates (6, 6’), along a second direction opposite to the first direction; while, in order to synchronously mutually bring said two pairs of plates (6, 6’) towards each other, the third actuator (10), by means of the respective stem (10’), actuates a sliding of the first pair of plates (6, 6’), and thus of the first movable racks (11 ), along said second direction, simultaneously producing a sliding of the second movable racks (12), and thus of the second pair of plates (6, 6’), along said first direction.

9. A method for operating an injection blow molding machine for plastic containers according to any one of the preceding claims, wherein, after the blowing of the containers in the double-row molding station, in order to remove said containers from said double-row molding station, the following steps are provided:- synchronously and equally making a first movement, with a first speed, of the two pairs of plates (6, 6’), mutually distancing them along a direction transverse to saidlongitudinal axis (X);- synchronously and equally making a second movement, with a second speed greater than said first speed, of each movable side part (15, 15’) with respect to the fixed central part (14) along said transverse direction, mutually distancing them for an opening of the two parallel rows of container molds;- synchronously and equally making a third movement, with said first speed, of the two rows of mold bottoms (16, 16’) with respect to the fixed central part (14) along said transverse direction, mutually distancing them; wherein there is provided a synchronization of said first movement, second movement and third movement whereby, during the movement of the two pairs of plates (6, 6’), and thus of the two rows of neck molds, and the simultaneous movement of the two rows of mold bottoms (16, 16’), the longitudinal axis of the blown containers remains vertical during said opening.

10. A method according to claim 9, wherein a first distancing stroke (C) of the movable side parts (15, 15’) from each other is twice a second distancing stroke (P2-P1 ) of both the two pairs of plates (6, 6’) from each other and the two rows of mold bottoms (16, 16’) from each other; and wherein said first distancing stroke (C) and said second distancing stroke (P2-P1) are carried out in a same period of time.

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