Device and method for transporting plastic preforms

Abstract

Device (1) for transporting plastic preforms (10, 10a) with a first transport unit (2) which transports the plastic preforms (10, 10a) along a predetermined transport path (P), wherein the transport unit (2) has a first guide element (12) which supports the plastic preforms (10, 10a) and relative to which the plastic preforms (10, 10a) move along the transport path (P), and wherein the transport unit (2) has a second guide element (14) which supports the plastic preforms (10, 10a) and relative to which the plastic preforms (10a, 10b) move along the predetermined transport path (P), and wherein the plastic preforms (10, 10a) are guided between these guide elements (12, 14), the guide elements supporting the plastic preforms at their support rings and a base body of the plastic preform moving downwards over the guide elements stands out,where, however, an opening of the plastic preform projects upwards beyond the guide elements (12, 14). characterized in that the device (1) has a control body (20) that can be moved by a movement of the plastic preforms (10a, 10), wherein the control body (20) can be brought into contact with at least a proportion of the plastic preforms (10) arranged and moving in a first position relative to the guide elements (12, 14) and is thus movable, wherein movement of the control body is blocked when the control body contacts a plastic preform (10a) arranged in a second position relative to the guide elements, wherein this blockage of the control body also prevents further transport of such an incorrectly oriented plastic preform.

Description

[0001] The invention relates to a device and a method for transporting and / or sorting plastic preforms. Such plastic preforms are used in the prior art to be expanded into plastic containers, particularly by applying compressed air. It is also known that the plastic preforms are transported and sorted. For example, the plastic preforms can fall from a hopper onto a sorting unit and be sorted therein. However, the problem can arise that the plastic preforms become wedged together or are transported in undesired arrangements or positions.

[0002] WO 2010 / 006 462 A1 describes a device and a method for singulating cylindrical bodies, and in particular plastic preforms. It includes a detection device that identifies incorrectly positioned and / or nested preforms and is equipped with a control unit for an ejection device. This may include a first ejection device for ejecting preforms and a second ejection device with a blow-out mechanism for ejecting preforms.

[0003] Especially at high production speeds, this device must react very quickly to corresponding error messages in order to eject incorrectly oriented plastic preforms. It has been shown that, particularly at the increasingly high production speeds demanded, this type of ejection does not always function flawlessly.

[0004] US patent 2008 / 0226763 A1 also discloses a device for storing plastic preforms, which includes a device for removing incorrectly positioned preforms. This device includes an ejection mechanism that can, for example, eject incorrectly positioned plastic preforms. Furthermore, this document discloses an adjusting device with which a guide rail for the plastic preforms can be moved so that the plastic preforms fall out of the transport path.

[0005] EP 2 065 320 A1 describes a device for aligning plastic preforms. This device also includes a so-called kicker wheel, which is positioned above the transport path of the plastic preforms to push away incorrectly oriented preforms.

[0006] EP 1 866 223 B1 describes a device and a method for straightening blanks for the production of plastic containers by blow molding. A rotary table with a top surface for receiving the disordered blanks is provided, as well as a guide element arranged above the rotary table, such that a gap is formed between the top surface of the rotary table and the guide element, the base body of the blanks being guided radially outwards through the gap.

[0007] From DE 696 24 779 T2, a device for the automatic removal of incorrectly oriented elements from a supply line of closures, plugs, or generally concave elements is known. For this purpose, a control element is provided that engages with the caps. Similar devices are known from US 4,995,503 A and EP 0 343 922 A1.

[0008] The state of the art described above has the disadvantage that, especially at high production speeds, ejecting poorly sorted plastic preforms is difficult. Furthermore, even when a poorly sorted plastic preform is detected, the production flow is not stopped. Additionally, the ejection devices described therein often eject multiple plastic preforms, and possibly also several other preforms that are otherwise correctly oriented.

[0009] The present invention is therefore based on the objective of creating a device for transporting plastic preforms which enables reliable ejection of the plastic preforms even at higher production speeds. This is achieved according to the invention by the subject matter of the independent claims. Advantageous embodiments and further developments are the subject of the dependent claims.

[0010] A device according to the invention for transporting plastic preforms comprises a first transport unit which transports the plastic preforms along a predetermined transport path, wherein the transport unit has a first guide element which supports the plastic preforms and against which the plastic preforms move along the transport path. The transport unit also has a second guide element which supports the plastic preforms and against which the plastic preforms move along the predetermined transport path. The plastic preforms are guided between these guide elements.

[0011] According to the invention, the device has a control body that can be moved or driven by a movement of the plastic preforms, wherein the control body can be brought into contact with at least a proportion of the plastic preforms arranged in a first position relative to the guide elements and moving, and can thus be moved.

[0012] It is therefore proposed according to the invention that a driveable control body is provided, which is driven precisely by the movement of the plastic preforms along the transport path. In particular, the control body is moved only by those plastic preforms that are arranged in a first position, especially a correct position, relative to the guide elements. In this way, the movement of this control body is an indication of whether the plastic preforms are being transported correctly and whether they are in the correct position relative to the guide elements. In addition, it is also possible to determine the quantity of transported plastic preforms using the control body or based on its movement.

[0013] In a further advantageous embodiment, the transport unit transports the plastic preforms one after the other or abutting each other. This preferably avoids individual transport of the plastic preforms.

[0014] In a further advantageous embodiment, at least one section of the plastic preforms projects beyond the guide elements in its longitudinal direction. Advantageously, two sections project beyond the guide elements in particularly preferably opposite directions. For example, the guide elements could support the plastic preforms at their support rings, with the base body of the plastic preform projecting downwards, while an opening of the plastic preform projects upwards.

[0015] In a further advantageous embodiment, the control body contacts each plastic preform; however, it would also be conceivable that only every nth plastic preform, for example every second, third, or fourth plastic preform, is contacted. This contact with the moving plastic preforms drives the control body mentioned above.

[0016] In a further advantageous embodiment, the movement of the control body is slowed down or blocked, and preferably blocked, when the control body contacts a plastic preform arranged in a second position relative to the guide elements. Advantageously, the control body is designed such that, for example, plastic preforms lying approximately parallel to the guide elements, approximately horizontally, or rotated by approximately 90° relative to the first position block the movement of the control body. In the event of such a blockage of the control body, it can be determined that incorrectly oriented plastic preforms are being transported.

[0017] According to the invention, this blockage of the control body also prevents such a misoriented plastic preform from being transported further. In this way, the transport of the plastic preforms starting from the misoriented plastic preform is blocked.

[0018] In a further advantageous embodiment, the device includes a reject mechanism for removing individual plastic preforms. This makes it possible, for example, for the control body to detect a misaligned plastic preform and remove it accordingly. It is also conceivable that several plastic preforms can be removed simultaneously.

[0019] In a further advantageous embodiment, the ejection device moves at least one of the two guide elements. This makes it possible for one of the two guide elements to be moved or shifted in such a way that the distance between the two guide elements increases, allowing the plastic preform to fall downwards due to gravity.

[0020] In a further advantageous embodiment, the device also has a second ejection device, such as a kicker wheel. This wheel can, for example, eject interlocking plastic preforms.

[0021] In a further preferred embodiment, at least one of the guide elements is designed as a rotatable roller. Advantageously, both guide elements are designed as rotatable rollers, the axes of which are particularly preferably parallel to each other. By rotating these rollers, the plastic preforms can be better aligned. Advantageously, the rollers rotate in opposite directions, and particularly advantageously such that they tend to lift the plastic preform against gravity.

[0022] In a further advantageous embodiment, the device includes a motion detection device that detects movement of the control body. This could, for example, be a light barrier suitable for detecting when the control body is stationary. However, it would also be possible for the motion detection device to operate on the basis of inductive elements in order to detect when the movement of the control body is interrupted or is interrupted.

[0023] In a further advantageous embodiment, the control body is rotatable about a predetermined axis. In particular, the control body is a rotatable control wheel, which is advantageously designed symmetrically with respect to its axis of rotation.

[0024] In a further advantageous embodiment, the control body is arranged above the transport path of the plastic preforms. The plastic preforms are preferably transported below the control body, and the control body contacts these plastic preforms (or at least a portion thereof) and is driven by their movement.

[0025] In a further advantageous embodiment, the control body has a plurality of projections suitable for engaging the openings of the plastic preforms. Particularly preferably, the control body is designed in the form of a vertically arranged star wheel, the points of which engage with the opening of the correctly sorted plastic preforms. This causes the control wheel to rotate. If the plastic preforms are poorly sorted or lying down, these star points cannot engage with the opening, and the respective preform remains stuck to the control body. In this case, the plastic preform can be ejected and reintroduced into the transport device.

[0026] Preferably, the control body has a multitude of projections (advantageously extending in a radial direction with respect to the axis of rotation of the control body) which are suitable for engaging in the openings of the plastic preforms. However, it would also be conceivable for the control body to contact the side walls of the plastic preforms with its projections and thus be driven by their movement. If, in this case, a plastic preform is lying horizontally, a longer gap would be created, and consequently, the control body would no longer be driven. This standstill of the control body could also be detected accordingly.

[0027] The embodiment involving the openings offers the advantage that the control body is not only blocked by the aforementioned misoriented plastic preform, but also blocks the movement of the plastic preform, thus preventing the transport of further plastic preforms. On the other hand, in other embodiments, it may be desirable for the transport of the remaining preforms to continue despite one misoriented preform.

[0028] In a further advantageous embodiment, the projections have a sawtooth profile. As mentioned above, the respective saw teeth engage in the openings of the plastic preforms.

[0029] The present invention further relates to a method for transporting plastic preforms, wherein the plastic preforms are transported along a predetermined transport path by means of a transport unit. According to the invention, the movement of the plastic preforms drives a control body, which is temporarily in contact with at least some of the moving plastic preforms, when the plastic preforms are arranged in a first position relative to the transport unit. Furthermore, the movement of this control body is slowed or blocked, and preferably blocked, when the control body comes into contact with at least one plastic preform that is arranged in a second position relative to the transport unit.

[0030] It is therefore also proposed from a procedural standpoint that a control element be provided which is driven particularly during normal operation, i.e. when correctly arranged plastic preforms are present, and which, conversely, is advantageously blocked when an incorrectly arranged plastic preform is present.

[0031] Preferably, in response to the detection of at least a temporary standstill of the control body, at least one plastic preform is ejected. Further advantages and embodiments can be seen from the attached drawings:

[0032] It shows: Fig. 1 a schematic representation of a device according to the invention; Fig. 2 a top view of the device from Fig. 1; Fig. 3 a partial view of the in Fig. 1 device shown; and Fig. 4 another detailed view of a device according to the invention.

[0033] Fig. Figure 1 shows a schematic representation of a device 1 according to the invention for transporting plastic preforms 10. The plastic preforms are conveyed along a transport path P. For this purpose, a transport unit 2 is provided. This transport unit 2 has a first guide element 12 and a second guide element 14. These two guide elements are arranged as rotatable rollers, which support the plastic preforms, in particular at their support ring. By rotating these rollers, the plastic preforms are transported along the transport path P. Reference numeral 40 denotes an ejection wheel, which serves, for example, to eject plastic preforms 10 that are arranged one above the other or wedged together.

[0034] In addition, a control body 20 is provided, which is also designed here as a control wheel rotatable about a pivot axis X. This pivot axis X is located above the transport path P of the plastic preforms and runs essentially perpendicular to the plane of the figure. This control wheel 20 has a plurality of star-shaped teeth 22 which engage in the openings 16 of the "well-sorted" plastic preforms 10. The control wheel is thus driven by the movement of the plastic preforms 10.

[0035] If the plastic preforms 10a are poorly sorted or lying down, the respective star point 22 cannot engage in the opening and the plastic preform 10a remains stuck on the star wheel 20.

[0036] Reference numeral 26 designates a motion detection device, which can also detect a standstill of the control body 20. If such a standstill of the control body 20 is detected, an automatic ejection can be activated, which also ejects the plastic preform 10a located here.

[0037] The control body 20 can be arranged downstream of the ejection device 40. The plastic preform thus ejected can be fed back into the transport device. Reference numeral 44 designates a further guide rail by means of which the plastic preforms 10 are transported further.

[0038] Fig. 2 shows another view of the in Fig. The device shown in Figure 1. Here again, guide elements 12 and 14 are provided, whereby, as shown, the guide elements can also be fixed rails. Reference numeral 12a denotes a rotatable end section of a roller 12. Reference numeral 30 denotes a discharge device, which is used, for example, in Fig. 2 can be raised to eject the poorly sorted plastic preform 10a. The control wheel is perpendicular to the plane of the figure, or its axis of rotation X runs parallel to the plane of the figure.

[0039] The kicker wheel 40 mentioned above (i.e. the ejection device) and the ejection device 30 can also be provided as an alternative.

[0040] As in Fig. As illustrated in Figure 3, the control body 20 can also be arranged in a discharge assembly of the device, i.e., after the two rollers mentioned above. In this case, the guide elements 12 and 14 are stationary rails, i.e., not rotating rollers. The individual projections 22 of the control body 20 are arranged such that they each engage in the openings 16 of the plastic preforms when these are transported adjacent to one another. This means that the distance between the individual projections 22 in the circumferential direction of the control body 20 essentially corresponds to the distance between the axes of symmetry of two consecutive plastic preforms.

[0041] It can also be seen that the projections 22 are shaped like shark fins, thus enabling intervention in the plastic preforms moving in direction P. The motion detection device 26 can in turn detect movement of the control body 20.

[0042] Fig. Figure 4 illustrates a further embodiment of the present invention. Here, the two guide elements 12 and 14 are again shown, wherein, in response to a standstill of the control body 20, for example, the guide element 14 can be retracted by means of two drive devices 34 and 36 in order to eject the corresponding plastic preforms located between the guide elements 12 and 14. It would also be possible to use a shorter guide element 14 than shown in Figure 4. Fig. 4 shown to withdraw, so that a correspondingly smaller number of plastic preforms are ejected when a fault occurs.

[0043] The applicant reserves the right to claim all features mentioned in the description as essential to the invention, provided that these features, individually or in combination, are novel compared to the prior art. Reference symbol list 1 Device 2 transport units 10 plastic preforms 10a poorly fitting plastic preforms 12 first guide element 12a rotatable end section 14 second guide element 16 outlets of the “well-sorted” plastic preforms 20 Control body / star wheel 22 star points 26 Motion detection device 30 Ejection device 34 Drive unit 36 Drive unit 40 Ejection wheel / kick wheel 44 Guide rail for transporting the plastic preforms P Transport route X axis of rotation

Claims

[1] Device (1) for transporting plastic preforms (10, 10a) with a first transport unit (2) which transports the plastic preforms (10, 10a) along a predetermined transport path (P), wherein the transport unit (2) has a first guide element (12) which supports the plastic preforms (10, 10a) and relative to which the plastic preforms (10, 10a) move along the transport path (P), and wherein the transport unit (2) has a second guide element (14) which supports the plastic preforms (10, 10a) and relative to which the plastic preforms (10a, 10b) move along the predetermined transport path (P), and wherein the plastic preforms (10, 10a) are guided between these guide elements (12, 14), wherein the guide elements support the plastic preforms at their support rings and a base body of the plastic preform moves downwards over the The guide elements stand out,whereas, in contrast, an opening of the plastic preform protrudes upwards above the guide elements (12, 14). characterized by , that the device (1) has a control body (20) that can be moved by a movement of the plastic preforms (10a, 10), wherein the control body (20) can be brought into contact with at least a proportion of the plastic preforms (10) arranged and moving in a first position relative to the guide elements (12, 14) and is thus movable, wherein a movement of the control body is blocked when the control body contacts a plastic preform (10a) arranged in a second position relative to the guide elements, wherein this blockage of the control body also prevents further transport of such an incorrectly oriented plastic preform. [2] Device (1) according to claim 1, characterized by, that the device (1) has a discharge device (30) for discharging individual plastic preforms (10a). [3] Device (1) according to at least one of the preceding claims, characterized by , that the device (1) has a motion detection device (26) for detecting a movement of the control body (20). [4] Device (1) according to at least one of the preceding claims, characterized by , that the control body (20) is rotatable about a predetermined axis of rotation (X). [5] Device (1) according to at least one of the preceding claims, characterized by , that the control body (20) is arranged above the transport path of the plastic preforms (10, 10a). [6] Device (1) according to at least one of the preceding claims, characterized by, that the control body (20) has a plurality of projections (22) which are suitable for engaging in openings (16) of the plastic preforms (10). [7] Device according to claim 6, characterized by , that the projections (22) have a sawtooth profile. [8] Method for transporting plastic preforms (10, 10a) with a device (1) according to one of the preceding claims, wherein the plastic preforms (10, 10a) are transported by means of a transport unit (2) along a predetermined transport path (P). characterized by, that by the movement of the plastic preforms (10) a control body (20), which is temporarily in contact with at least a part of the moving plastic preforms (10), is driven when the plastic preforms are arranged in a first position relative to the transport unit (2), and a movement of this control body (20) is blocked when the control body (20) comes into contact with at least one plastic preform (10a) which is arranged in a second position relative to the transport unit (2), and by this blockage of the control body it is also prevented that such an incorrectly oriented plastic preform (10, 10a) is transported further.

Images