Stretch blow molding machine for the production of containers from container preforms

Abstract

Stretch blow molding machine (2) for producing containers from container preforms in a continuous flow, with several circulating conveying devices (40-45) for the containers arranged successively in the conveying direction of the containers, and at least two drives for the circulating conveying devices (40-45), wherein at least some of the circulating conveying devices (40-45) each have interchangeable components adapted to a format of the containers, and wherein the stretch blow molding machine (2) comprises a machine enclosure (18) with at least one closable format change opening (19) which provides access to an exchange area (I, II, III, IV) for exchanging the interchangeable components on at least one of the circulating conveying devices (40-45), wherein each of the circulating conveying devices (40-45) either has a circulating conveying device (40-45) associated with the exchange area (I, II, III, IV), the driven movable components of which are at least partially and / or at least temporarily located within the exchange area (I,II, III, IV), or another circulating conveying device (40-45) whose driven movable components are all always located outside the changeover area (I, II, III, IV). The stretch blow molding machine (2) according to the invention is further developed in that the changeover area (I, II, III, IV) has suitable safety measures to prevent a person operating in the changeover area (I, II, III, IV) from interfering with moving components of the other circulating conveying devices (40-45).

Description

[0001] The invention relates to a stretch blow molding machine for producing containers from container preforms in a continuous flow, comprising a plurality of circulating conveyors for the containers arranged successively in the conveying direction of the containers and at least two drives for the circulating conveyors, wherein at least some of the circulating conveyors each have interchangeable components adapted to a format of the containers, and wherein the stretch blow molding machine comprises a machine casing with at least one closable format change opening, which makes a change area accessible for exchanging the interchangeable components on at least one of the circulating conveyors, wherein each of the circulating conveyors is either a circulating conveyor assigned to the change area, the driven movable components of which are located at least partially and / or at least temporarily within the change area, or another circulating conveyor,whose driven movable components are always outside the change range,

[0002] The invention also relates to a block machine for producing and treating containers in a continuous flow comprising a stretch blow molding machine.

[0003] The invention further relates to an operating method for a block machine with a stretch blow molding machine or a stretch blow molding machine, wherein the stretch blow molding machine is designed and configured to produce containers from container preforms in a continuous stream with a plurality of circulating conveyor devices for the containers arranged one after the other in the conveying direction of the containers and at least two drives for the circulating conveyor devices, wherein at least some of the circulating conveyor devices each have interchangeable components adapted to a format of the containers.

[0004] To replace all of the interchangeable components in a circulating conveyor system, the entire circulating conveyor system must be rotated, usually in several steps, for one complete revolution. It is essential to avoid injuries from moving machine parts. For safety reasons, the current state of the art therefore stipulates that the entire machine enclosure must be closed when rotating the circulating conveyor system. To make matters worse, the number and setup time for replacing the interchangeable components often vary greatly between different circulating conveyor systems. In practice, all of this means that the interchangeable components of different circulating conveyor systems are usually replaced one after the other, and other maintenance and adjustment work is generally not possible in parallel with the format change for safety reasons. Changing the format for the entire machine is therefore time-consuming.

[0005] The invention is based on the object of reducing the time required for format changes on a machine for producing and / or treating containers compared to the prior art, without compromising operational reliability.

[0006] According to the invention, this object is achieved by a machine for producing and / or treating containers in a continuous flow, comprising a plurality of circulating conveyors for the containers arranged successively in the conveying direction of the containers and at least two drives for the circulating conveyors, wherein at least some of the circulating conveyors each have interchangeable components adapted to a format of the containers, and wherein the machine comprises a machine casing with at least one closable format change opening, which makes a change area accessible for exchanging the interchangeable components on at least one of the circulating conveyors, wherein each of the circulating conveyors is either a circulating conveyor assigned to the change area, the driven movable components of which are located at least partially and / or at least temporarily within the change area, or another circulating conveyor,whose driven movable components are all always located outside the changeover area, wherein a machine according to the invention is further developed in that the changeover area has suitable safety measures to prevent a person operating in the changeover area from interfering with moving components of the other circulating conveyor devices.

[0007] In the context of the invention, a continuous flow is understood in particular to mean that the containers are lined up upon entry into the machine according to the invention and are conveyed through the machine in an unchanged sequence by means of the circulating conveyors. The term "container" refers not only to the finished product at the machine outlet, but also to the precursors fed into the machine at the machine inlet, as well as all intermediate stages during production or processing in the machine.

[0008] The invention enables the establishment of several independent safety zones within the machine according to the invention, for which a safety release for rotating or moving the circulating conveyor devices assigned to the various safety zones can be issued independently of one another. For this purpose, at least two drives are provided to enable individual or groups of circulating conveyor devices to be moved or rotated separately from one another. Thus, within the scope of the invention, the at least two drives can be operated both synchronously and separately from one another.

[0009] In particular, the invention envisions the changeover area and the circulating conveyors associated with the changeover area forming a safety zone independent of the rest of the machine, which is separated from the rest of the machine by the safety measures provided by the invention. This allows the format changeover opening to be opened safely even when the other circulating conveyors are rotating. Accordingly, the machine's safety control system can enable the rotation of the other circulating conveyors regardless of the closed state of the format changeover opening.

[0010] Within the scope of the invention, a format changeover opening according to the invention differs from a conventional lockable access opening in the machine enclosure, particularly in the changeover area provided according to the invention with appropriate safety measures. Accordingly, the closed state of any existing conventional access openings must be taken into account for the safe rotation release or safety release of all circulating conveyor devices.

[0011] A suitable safety measure within the scope of the invention consists in a sufficiently large distance, adapted to the size of the format change opening in question, between this format change opening and the driven, movable components of at least one of the other circulating conveyor devices.

[0012] The required minimum distance between the format changeover opening and the driven, moving components of the other conveyor systems is generally smaller for smaller format changeover openings because the reach of a person performing the format change is generally shorter through a smaller opening. For example, a small opening only allows for reaching in with an arm, while a medium-sized opening allows for leaning in with the upper body, and a large opening may even allow for stepping in behind the machine enclosure.

[0013] In this context, it should be noted in particular that a format change opening within the scope of the invention can also be an opening in a larger door of the machine casing that can be closed with a flap, provided that the size of the opening is sufficient for the intended format change.

[0014] Accordingly, it is generally advantageous if the format change opening according to the invention is only as large as the intended format change requires.

[0015] A further safety measure suitable within the scope of the invention comprises a separating device, in particular a partition wall, which is arranged between the changing area and the driven movable components of at least one of the other circulating conveyor devices.

[0016] A separating device is particularly useful when a sufficient distance between the changing area and the driven, movable components of one of the other circulating conveyor devices is not possible due to the design.

[0017] A further safety measure suitable within the scope of the invention comprises a penetration detection device connected to a safety shutdown between the exchange area and at least one of the remaining circulating conveyor devices, wherein the safety shutdown stops and / or blocks the drive or drives of the respective circulating conveyor device or devices as soon as the penetration detection device is triggered.

[0018] Securing the exchange area by means of a penetration detection device is particularly suitable when a separating device would have to block the conveying path of the containers in order to be effective as a safety measure within the meaning of the invention.

[0019] A penetration detection device according to the invention comprises, for example, one or more light barriers which can be deactivated in particular for normal operation in order not to be triggered by the containers conveyed during normal operation.

[0020] Within the scope of the invention, in particular several and different safety measures can be provided in combination in order to protect the changing area from all other circulating conveyor devices.

[0021] In the invention, it is particularly conceived that each of the at least two drives either exclusively drives circulating conveyor devices assigned to the changeover area or exclusively drives other circulating conveyor devices.

[0022] For a parallel format change on different circulating conveyor devices, it is particularly advantageous if the machine according to the invention comprises a plurality of closable format change openings in the machine casing, each of which makes a different change area accessible, wherein preferably the format-dependent change components of a single one of the circulating conveyor devices are accessible via only exactly one of the format change openings and the corresponding change area.

[0023] For the purposes of the invention, the terms "circulating conveyor device assigned to a changeover area" and "other circulating conveyor device" are always to be understood as referring to a specific changeover area. The same circulating conveyor device can be assigned to one of the multiple changeover areas, while the same circulating conveyor device represents a remaining circulating conveyor device within the meaning of the invention for another changeover area.

[0024] If several format change openings or change areas are present, the previously described features and advantages according to the invention are preferably realized for all of the change areas and for all circulating conveyor devices with respect to each of the change areas.

[0025] In this case, it is particularly advantageous if the machine includes a separate drive for at least some of the circulating conveyors. Individual drives for the circulating conveyors are conceivable, for example.

[0026] Within the scope of the invention, it is particularly provided that the stretch blow molding machine according to the invention has a heating device for the container preforms with a first circulating conveyor device, a second circulating conveyor device designed as a forming device for forming the container preforms into plastic containers and at least one third circulating conveyor device designed as a transfer device for the container preforms or the plastic containers.

[0027] For example, the interchangeable components of the first circulating conveyor device comprise transport mandrels and / or the interchangeable components of the second circulating conveyor device comprise blow molds and / or the interchangeable components of the third circulating conveyor device comprise holding tongs.

[0028] The object underlying the invention is also achieved by a block machine for producing and treating containers in a continuous flow with a stretch blow molding machine according to the invention.

[0029] Within the scope of the invention, a block machine is understood, in particular, to be a unit comprising several functional individual machines through which the containers pass in a continuous stream without intermediate separation. In addition to the stretch blow molding machine according to the invention, corresponding individual machines include, for example, but are not limited to, a filling machine or a labeling machine. Within the scope of the invention, this does not preclude the individual machines from performing several coordinated treatments or treatment steps on the containers, for example, heating and forming in a stretch blow molding machine or filling and closing in a filling machine.

[0030] The object underlying the invention is further achieved by an operating method for a block machine with a stretch blow molding machine or a stretch blow molding machine, wherein the stretch blow molding machine is designed and configured to produce containers from container preforms in a continuous stream with a plurality of circulating conveyor devices for the containers arranged successively in the conveying direction of the containers and at least two drives for the circulating conveyor devices, wherein at least some of the circulating conveyor devices each have interchangeable components adapted to a format of the containers, wherein the operating method according to the invention is further developed in that the at least two drives are operated synchronously with a uniform safety release for the production of containers and individually with their own safety releases for exchanging the interchangeable components.

[0031] The invention will be explained in more detail below with reference to an embodiment of the invention, which is illustrated in the drawing. Fig. 1 schematically shows a block machine according to the invention with a stretch blow molding machine according to the invention and a labeling machine.

[0032] In Fig. 1 shows a block machine 1 according to the invention with a stretch blow molding machine 2 according to the invention and a labeling machine 3.

[0033] The stretch blow molding machine according to the invention is based on a two-stage manufacturing process for plastic containers, in which, in a first stage, plastic raw materials are melted and processed, for example, by injection molding, into container blanks. The container blanks are also referred to as preforms, container preforms, or preforms. Fig.The blow molding machine 2 according to the invention shown in Figure 1 implements only the second stage of the container manufacturing process, in which the preforms are formed into containers. For this purpose, the preforms are thermally conditioned by means of a heating device 20 and then formed into the desired containers by means of a forming device 22 under the action of compressed air.

[0034] The prefabricated preforms are first stored in a silo 10, aligned by a roller sorter 14, and fed in a stacked row to the stretch blow molding machine 2. This is achieved, for example, by means of an inclined discharge rail 16, as shown in the drawing. The required height is achieved by means of an inclined conveyor 12 between the silo 10 and the roller sorter 14. Alternatively, the aligned preforms can also be stacked using a compressed air conveyor.

[0035] The accumulated preforms are separated at the entrance of the stretch blow molding machine 2 by means of an infeed starwheel 40 and pass through the entire block machine 1 in a continuous stream without interrupting this separation. For this purpose, the block machine 1 according to the invention, and thus also the stretch blow molding machine 2 according to the invention, have circulating conveyors 40-45, between which the preforms or the containers produced therefrom are transferred. The processing of the preforms and containers takes place during circulation on the appropriately equipped circulating conveyors 41, 43, 45 of the heating device 20 and the forming device 22 of the stretch blow molding machine 2 or the labeling machine 3.

[0036] In the heating device 20, the preforms are conveyed in close succession past stationary heating elements, such as infrared radiators, by means of a mandrel chain 41. The transport mandrels of the mandrel chain 41 engage the mouth area of ​​the preforms and are adapted accordingly to the dimensions of the preforms in use. The transport mandrels, or at least their mandrel heads that interact with the mouth area of ​​the preforms, must be replaced during a format change. Replacing a single transport mandrel usually requires only a few steps. Depending on the machine size, however, several hundred transport mandrels may need to be replaced.

[0037] The circulating conveyor device 43 of the forming device 22 is designed as a blowing wheel 43, on which blowing stations, each with a blow mold, are arranged. The spacing of the blow molds on the blowing wheel 43 is significantly greater than the spacing of the transport mandrels of the mandrel chain 41.

[0038] Transfer starwheels 42 are provided for feeding the preforms to and removing the formed containers from the blowing wheel 43. These transfer starwheels simultaneously manage the pitch adjustment between the mandrel chain 41 and the blowing wheel 43, or between the blowing wheel 43 and the downstream circulating conveyors 44. The preforms or containers are held on the transfer starwheels 42 by means of holding tongs that engage the preforms below the mouth and are adapted to the outer diameter of the preforms or containers in the designated section. Changing them is comparatively simple, since the individual holding tongs can be quickly replaced and the transfer starwheel 42 has only a few holding tongs.

[0039] To form containers, the preforms are placed in a blow mold, connected to a compressed air supply via a blow nozzle, and expanded within the mold. In addition to compressed air, the stretch blow molding process also uses a stretch rod to mechanically pressurize the preforms longitudinally. This typically occurs during a single revolution of the corresponding blow molding station on the rotating blow molding wheel 43.

[0040] The blow mold, blow nozzle, and stretch rod are each adapted to the preforms used and the containers to be produced and must be changed accordingly for a format change. Unlike with the mandrel chain, only a few blow stations need to be converted, but changing them for each individual blow station is significantly more complex and takes a correspondingly long time.

[0041] The block machine 1 further comprises a labeling machine 3, in which the containers produced in this way are provided with labels. For this purpose, the labeling machine 3 comprises a labeling wheel 45 with labeling stations, as well as a series of transfer wheels 44 and transfer star wheels 42. These transfer wheels 44 and transfer star wheels 42 also have container grippers, which depend on the container format and may need to be replaced accordingly when changing formats.

[0042] The containers thus produced and labeled leave the block machine 1 again as a continuous stream, which is generally subjected to further processing, such as filling and / or packaging. Within the scope of the invention, it is harmless if the separation and / or the continuous stream are interrupted during this subsequent processing.

[0043] The individual circulating conveyor devices 40-45 each have individual drives, for example. However, the inventive concept does not conflict with the possibility of individual circulating conveyor devices 40-45 being driven in pairs or groups by a common drive. In particular, it is conceivable that the inlet starwheel 40 is mechanically coupled to the mandrel chain 41, for example, by means of a toothed system or a transmission belt, and does not have a separate drive.

[0044] The drives are operated or controlled in a synchronized manner for the production and treatment of the containers in order to ensure that the containers are conveyed in a continuous flow through the block machine 1.

[0045] The entire block machine 1 is enclosed by a machine enclosure 18, which also serves, in particular, as a safety barrier for the rapidly rotating circulating conveyors 40-45 during operation. The numerous openings or doors shown in the machine enclosure 18, which allow access to the individual components of the block machine 1 when at a standstill, must all be closed during production and are secured in such a way that the block machine 1 is immediately stopped when one of the access doors is opened.

[0046] According to the invention, some of the access openings are provided as format change openings 19, which may be opened for a format change and which are integrated into the safety circuit of the block machine 1 or the stretch blow molding machine 2 and / or the labeling machine 3 in such a way that, during maintenance or format change operation, a slow rotation of the circulating conveyor devices 40-45 is fundamentally possible even when the format change openings 19 are open, as long as the other access openings are closed.

[0047] Each format change opening 19 is assigned a safety zone I-IV within which the format change takes place, with each of the circulating conveyor devices 40-45 passing through or touching at most one of the safety zones. This enables the invention to perform a format change at multiple circulating conveyor devices 40-45 or at multiple format change openings 19 simultaneously and independently of one another. In particular, the invention enables the various circulating conveyor devices 40-45 to rotate independently of one another and at different speeds without compromising safety. For this purpose, the drives of the circulating conveyor devices 40-45 are suitably operated or controlled separately from one another.

[0048] In order to ensure the safety of the persons involved in the format change, each safety area I-IV has suitable protective measures that prevent intervention into rotating or moving components outside the respective safety area I-IV during the format change.

[0049] In the case of safety area I, which is intended for changing the transport mandrels on the mandrel chain 41, these safety measures include, in particular, the positioning of the corresponding format change opening 19, which is arranged at a sufficiently large distance from all other circulating conveyor devices 40, 42-45, in particular the blowing wheel 43 and the transfer star 42 between the mandrel chain 41 and the blowing wheel 43. Even when the format change opening in safety area I is open, these circulating conveyor devices 40, 42-45 are therefore inaccessible, so that any rotation of these circulating conveyor devices 40, 42-45 is harmless from a safety perspective.

[0050] Safety area II with the corresponding format change opening 19 is provided for a format change at the blowing stations of the blowing wheel 43. At this point, it is not possible to maintain a sufficiently large safety distance to the transfer star 42 between the mandrel chain 41 and the blowing wheel 43. Safety area II is therefore preferably delimited from the described transfer star 42 by a partition wall, which effectively prevents access from safety area II into the transfer star 42.

[0051] Safety area III with the corresponding format change opening 19 is provided for format changes on the holding clamps of the two transfer star wheels 42 and the first transfer wheel 44 toward the labeling machine 3. The format change opening 19 is designed at this location, for example, as a small flap within a larger access door, so that while one can reach through the flap and reach the holding clamps of the transfer star wheels 42 and the transfer wheel 44, one cannot step behind the machine cover 18 or lean into it. This prevents access to the more distant blowing wheel 43.

[0052] Also relevant for safety considerations is the infeed starwheel 40, which, due to its design, may be driven synchronously with the mandrel chain 41, but must remain accessible for possible replacement. A fixed partition wall may therefore not be practical. In these cases, it is advisable to demarcate safety area III from the infeed starwheel 40 with a light barrier. This light barrier is connected to the release for the rotation of the mandrel chain 41 and thus of the infeed starwheel 40, and immediately blocks rotation when triggered. This, in turn, guarantees safety because intervention in stationary components does not pose an increased risk of injury.

[0053] As an alternative to a light barrier, a mobile partition wall is also conceivable, the correct positioning of which is monitored by suitable switches coupled to the rotation release of the mandrel chain 41 or the inlet star 40. This prevents accidental triggering, which cannot be ruled out with a light barrier.

[0054] The transfer starwheels 42 and the previously undiscussed transfer wheels 44 of the labeling machine 3 are accessible together via a single safety area IV with a corresponding format change opening 19. No parallel format change is provided for these five circulating conveyor devices 42, 44 in the illustrated embodiment, but this is unproblematic given the rapid change of the individual holding clamps and their small overall number.

[0055] At least one complete rotation is required for each format change on the individual circulating conveyors 40-45. For this purpose, for example, the drive of the corresponding circulating conveyor 40-45 can be disengaged so that the corresponding circulating conveyor 40-45 can continue to rotate manually during the format change. This is particularly suitable for the smaller transfer starwheels 42 and transfer wheels 44.

[0056] Larger and heavier circulating conveyor devices such as the mandrel chain 41 or the blowing wheel 43 are advantageously further rotated mechanically for the format change, wherein this rotation takes place slowly or step by step, particularly for safety reasons, and is controlled by suitable operating elements in the area of ​​the corresponding format change opening 19. REFERENCE SYMBOL 1 block machine 2 stretch blow molding machines 3 labeling machine 10 silos 12 steep conveyors 14 roller sorters 16 Drain rail 18 Machine cover 19 Format change opening 20 Heating device 22 Forming device 40 inlet star 41 Thorn Chain 42 Transfer Star 43 blowing wheel 44 Transfer wheel 45 Labeling wheel I, II, III, IV transition area

Claims

[1] Stretch blow molding machine (2) for producing containers from container preforms in a continuous flow, comprising a plurality of circulating conveyor devices (40-45) for the containers arranged successively in the conveying direction of the containers, and at least two drives for the circulating conveyor devices (40-45), wherein at least some of the circulating conveyor devices (40-45) each have interchangeable components adapted to a format of the containers, and wherein the stretch blow molding machine (2) comprises a machine casing (18) with at least one closable format change opening (19) which makes a change area (I, II, III, IV) accessible for exchanging the interchangeable components on at least one of the circulating conveyor devices (40-45), wherein each of the circulating conveyor devices (40-45) has either a circulating conveyor device (40-45) assigned to the change area (I, II, III, IV),whose driven movable components are located at least partially and / or at least temporarily within the changeover area (I, II, III, IV), or another circulating conveyor device (40-45), whose driven movable components are all always located outside the changeover area (I, II, III, IV), characterized by that the changeover area (I, II, III, IV) has suitable safety measures to prevent a person operating in the changeover area (I, II, III, IV) from interfering with moving components of the other circulating conveyor devices (40-45). [2] Stretch blow molding machine (2) according to claim 1, characterized by that one of the safety measures consists in a sufficiently large distance, adapted to the size of the format change opening (19) in question, between this format change opening (19) and the driven movable components of at least one of the other circulating conveyor devices (40-45). [3] Stretch blow molding machine (2) according to claim 1 or 2, characterized by that one of the safety measures comprises a separating device, in particular a partition wall, which is arranged between the changing area (I, II, III, IV) and the driven movable components of at least one of the other circulating conveyor devices (40-45). [4] Stretch blow molding machine (2) according to one of claims 1 to 3, characterized by that one of the safety measures comprises a penetration detection device connected to a safety shutdown, in particular one or more light barriers, between the changeover area (I, II, III, IV) and at least one of the remaining circulating conveyor devices (40-45), wherein the safety shutdown stops and / or blocks the drive or drives of the relevant circulating conveyor device (40-45) or circulating conveyor devices (40-45) as soon as the penetration detection device is triggered. [5] Stretch blow molding machine (2) according to one of claims 1 to 4, characterized by that each of the at least two drives drives either exclusively circulating conveyor devices (40-45) assigned to the changeover area (I, II, III, IV) or exclusively other circulating conveyor devices (40-45). [6] Stretch blow molding machine (2) according to one of claims 1 to 5, characterized by in that the stretch blow molding machine (2) comprises a plurality of closable format change openings (19) in the machine casing (18), each of which makes a different change area (I, II, III, IV) accessible, wherein preferably the format-dependent change components of a single one of the circulating conveyor devices (40-45) are accessible via exclusively exactly one of the format change openings (19) and the corresponding change area (I, II, III, IV). [7] Stretch blow molding machine (2) according to one of claims 1 to 6, characterized bythat the stretch blow molding machine (2) comprises a separate drive for at least some of the circulating conveyor devices (40-45). [8] Stretch blow molding machine (2) according to one of claims 1 to 7, characterized by in that the stretch blow molding machine (2) has a heating device (20) for the container preforms with a first circulating conveyor device (41), a second circulating conveyor device (43) designed as a forming device (22) for forming the container preforms into plastic containers, and at least one third circulating conveyor device (42) designed as a transfer device (42) for the container preforms or the plastic containers, wherein in particular the interchangeable components of the first circulating conveyor device (41) comprise transport mandrels and / or the interchangeable components of the second circulating conveyor device (43) comprise blow molds and / or the interchangeable components of the third circulating conveyor device (42) comprise holding tongs. [9] Block machine (1) for producing and treating containers in a continuous flow, comprising a stretch blow molding machine (2) according to one of claims 1 to 8. [10] Operating method for a block machine (1) with a stretch blow molding machine (2) or a stretch blow molding machine (2), wherein the stretch blow molding machine (2) is designed and configured to produce containers from container preforms in a continuous stream with a plurality of circulating conveyor devices (40-45) for the containers arranged successively in the conveying direction of the containers and at least two drives for the circulating conveyor devices (40-45), wherein at least some of the circulating conveyor devices (40-45) each have interchangeable components adapted to a format of the containers, characterized bythat at least two drives for the production of containers are operated synchronously with a uniform safety release and for the exchange of the interchangeable components are operated individually with their own safety releases

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