Gripping device for gripping the inner opening of a plastic container

Abstract

Gripping device (1; 101) for gripping an inner opening area (10) of a plastic container (11), in particular a preform (12) of such a plastic container (11), with a gripping head unit (2) having an axial gripping depth (15) for at least partial axial insertion into the inner opening area (10), wherein the gripping head unit (2) comprises gripping elements (3, 4, 5, 6) which are arranged radially (9) outwards against an inner surface of the inner opening area (10) on the gripping device (1; 101) for gripping the inner opening area (10), characterized in that the gripping device (1) has a transverse pin element (40) which, in the operating state of the gripping device (1), serves to fasten the gripping device (1) to a transport device and the transverse pin element (40) is located in the upper third (37) of a carrier sleeve (31).

Description

[0001] The invention relates to a gripping device for gripping an inner opening area of ​​a plastic container, in particular a preform of such a plastic container, with a gripping head unit having an axial gripping depth for at least partially axial insertion into the inner opening area, wherein the gripping head unit comprises gripping elements which are arranged radially outwards against an inner surface of the inner opening area on the gripping device for gripping the inner opening area.

[0002] Such gripping devices are already well known from the prior art and serve, in particular, to grip preforms that are expanded into plastic containers, such as plastic beverage bottles, using stretch blow molding machines, in order to handle and transport them safely within a production plant. Due to very high tolerance requirements, for example, a low diameter tolerance of +0.05 -0.04 mm, which a preform should exhibit, especially in its mouth area, it is currently necessary to maintain a large number of variants of these gripping devices. Furthermore, if the mouth height is less than 6 mm, this tight diameter tolerance also leads to fixation problems. Therefore, the values ​​to be considered regarding the mouth height and the diameter tolerance are inextricably linked. The required very large number of differently designed or...Differently sized preforms result in a disadvantageously high manufacturing effort and correspondingly expensive gripping devices.

[0003] For example, the German patent application DE 10 2009 009 885 A1 of the applicant describes a gripping element for gripping plastic preforms. This is an internal gripper in which gripping elements are pressed against an inner wall of the plastic preform.

[0004] Another German patent application, DE 100 60 405 A1, describes an internal gripper for pipes and bores. A large clamping range is achieved by increasing the axial length of the internal gripper, as the stroke range of extendable jaws is determined by the travel of a pressure piece.

[0005] Another German patent application, DE 196 18 206 A1, discloses a method and a device for coating glass containers and coated glass containers. The glass containers are heated to an elevated temperature in a cooling oven and gripped from the cooling oven conveyor belt by gripping units of a gripping device.

[0006] The object of the present invention is, in particular, to overcome the aforementioned disadvantages.

[0007] According to a first aspect of the invention, the object of the invention is solved by a gripping device for gripping an inner opening area of ​​a plastic container, in particular a preform of such a plastic container, with a gripping head unit having an axial gripping depth for at least partially axial insertion into the inner opening area, wherein the gripping head unit comprises gripping elements which are arranged radially outwards against an inner surface of the inner opening area on the gripping device for gripping the inner opening area, wherein the gripping device is characterized by an adjustment device for variably adjusting the axial gripping depth of the gripping head unit as a function of the opening depth of the inner opening area.

[0008] With the aid of this adjustment device according to the invention, it is advantageously possible to precisely adapt the present gripping device to different opening heights of various preforms without having to replace the gripping device or components thereof.

[0009] According to a further aspect of the invention, the present problem is also solved by a gripping device for gripping an inner opening area of ​​a plastic container, in particular a preform of such a plastic container, with a gripping head unit having an axial gripping depth for at least partially axial insertion into the inner opening area, wherein the gripping head unit comprises gripping elements which are arranged radially outwards against an inner surface of the inner opening area on the gripping device for gripping the inner opening area, and wherein the gripping head unit has a diameter tolerance field of + / -0.9 mm in the radial disengagement direction of the gripping elements, wherein the gripping elements are arranged to be disengaged radially translationally depending on a translational actuation direction along an axial displacement axis.

[0010] Advantageously, the high achievable diameter tolerance of + / -0.9 with regard to the tolerance field M2 concerning the inner diameter of a preform allows a significantly larger number of different preforms to be handled with a single gripping device.

[0011] This translational disengagement can be implemented particularly simply by means of an actuating unit comprising an axially spring-loaded switching shaft element, which is arranged to be axially displaceable within a support sleeve element of the gripping device. Preferably, this preloading is achieved by means of disc spring elements.

[0012] The switching wave element can be actuated, for example, by an interaction with an external switching curve.

[0013] Furthermore, it is advantageous if the switching shaft element is radially mounted within the support shell element. This makes the present gripping device extremely simple to construct.

[0014] Advantageously, the gripping elements have inwardly directed release ramps which can be actuated in an alternating manner with corresponding counter ramps.

[0015] Preferably, the switching shaft element advantageously comprises the radially outwardly directed counter-slopes which interact with the release slopes, thereby enabling a radial translational movement of the gripping elements.

[0016] Preferably, the release ramps are also oriented downwards in the gripping device. In this respect, they are positioned facing away from the carrier sleeve.

[0017] Accordingly, the opposing slopes point upwards in the opposite direction and are arranged facing the support sleeve.

[0018] Furthermore, it is advantageous if the gripping head unit has an engagement mechanism for the radial engagement of the individual gripping elements. This allows for a simple and reliable radial displacement of the gripping elements onto the axial displacement axis of the gripping device.

[0019] With such an advantageously designed actuating unit, significantly larger tolerance ranges can be achieved and reliably maintained than has been the norm until now.

[0020] An expert understands how the aforementioned adjustment device can be designed in a wide variety of configurations. In practice, it has proven particularly effective if the adjustment device includes an axially movable muzzle stop element against which the end face of the muzzle's inner area abuts to define the axial engagement depth. This allows the axial engagement depth to be adjusted almost arbitrarily easily on the gripper head unit, depending on the design of the muzzle area of ​​the respective preform.

[0021] If the axially displaceable muzzle stop element includes stop bar elements arranged concentrically around an axial displacement axis of the gripping device, the front face of the muzzle area can rest particularly securely against the muzzle stop element.

[0022] The individual stop bar elements preferably extend with their longitudinal extent in the direction of the axial displacement axis and are connected to each other on their side facing away from the stop ends by a circumferentially running collar area of ​​the muzzle stop element.

[0023] Furthermore, it is advantageous if the gripping elements are arranged concentrically around an axial displacement direction in the circumferential direction of the gripping head unit. This ensures a secure gripping of the preform in the mouth area.

[0024] The present gripping device can be built in a particularly compact manner if the gripping elements are arranged in the circumferential direction of the gripping head unit between stop elements arranged concentrically around an axial displacement axis of the gripping device.

[0025] In a preferred embodiment, a stop element and a gripping element alternate sequentially along the circumference of the head unit, with the number of stop elements and gripping elements used varying. This alternating arrangement of the stop elements and gripping elements significantly reduces the risk of the preform being picked up at an angle or at an angle.

[0026] The structural design of the adjusting device can be further significantly reduced if the gripping elements, together with stop bar elements of the axially displaceable muzzle stop element, are rotatably arranged around an axial displacement direction of the gripping device in the circumferential direction of the gripping head unit.

[0027] A particularly preferred embodiment provides that the adjusting device includes, in particular, a self-locking fine thread on which the axially displaceable muzzle stop element is mounted in a manner that allows axial displacement but can be fixed in place. Advantageously, the self-locking fine thread provides self-locking with respect to the rotational capacity of the axially displaceable muzzle stop element, thereby enabling the axially displaceable muzzle stop element to be positioned with exceptional ease with regard to the axial engagement depth of the gripping head unit.

[0028] Advantageously, the self-locking fine thread allows for stepless adjustment of the axial engagement depth.

[0029] However, it is also conceivable to provide a ratchet mechanism in conjunction with the self-locking fine thread, by means of which possible axial engagement depths can be specified, thereby facilitating adjustment on the adjusting device.

[0030] Alternatively, this adjustment can also be made precisely if the adjustment device includes an adjustment sleeve element that can be temporarily attached to the gripping device.

[0031] It is understood that for differently adjustable axial gripping depths, correspondingly differently designed adjustment sleeve elements may also be provided, which can be temporarily attached to a defined location of the gripping device, for example a radial retaining pin of a bayonet lock of the gripping device, during an adjustment process.

[0032] The self-locking fine thread on the gripping device can be implemented very simply in terms of construction if the self-locking fine thread is designed as an external thread on a support sleeve of the gripping device.

[0033] In order to be able to easily rotate the axially displaceable muzzle stop element on the self-locking fine thread and accordingly move it in a targeted manner in the direction of the axial displacement axis, it is advantageous if the axially displaceable muzzle stop element has a tool receiving area on its side facing away from the stop web elements.

[0034] Preferably, the tool holding area is designed such that a wrench tool or the like can be attached radially from the outside to it in order to rotate the axially displaceable muzzle stop element and thereby preset the axial engagement depth of the gripping head unit.

[0035] Further advantages, objectives, and features of the present invention are explained with reference to the accompanying drawing and the following description, in which exemplary gripping devices, each with an adjustment device for variably adjusting the axial gripping depth of the gripping head unit as a function of the opening depth of the inner opening area, are shown and described. The drawing shows: Fig. 1 schematically a perspective view of a first gripping device with an adjustment device for variably adjusting the axial gripping depth of the gripping head unit; Fig. 2 schematically a partially cutaway view of the gripping device from the Fig. 1 with a gripping head unit partially inserted into the mouth area of ​​a preform and with the preform grasped at the inside of the mouth area; Fig. 3 schematically another partially cutaway view of the gripping device from the Fig. 1 and Fig. 2 with a gripping head unit pulled out from the inner mouth area of ​​the preform; Fig. 4 schematically another perspective view of the gripping device from the Fig. 1 to 3 with temporarily attached adjusting sleeve element and attached open-end wrench tool for adjusting the axial engagement depth into the inner mouth area of ​​the preform made from the Fig. 2 and Fig. 3; Fig. 5 schematically a partially cut-away perspective view of the gripping device according to the illustration after Fig. 4; and Fig. Figure 6 schematically shows a partially cut perspective view of an alternative gripping device with an adjustment device for variably adjusting the axial gripping depth of the gripping head unit.

[0036] The in the Fig. The gripping device 1 shown in Figures 1 to 5 has a gripping head unit 2 with a total of four gripping elements 3, 4, 5 and 6, which can be extended radially 9 (shown here only as an example) outwards with respect to an axial displacement direction 7 of the gripping device 1 along an axial displacement axis 8 of the gripping device 1 (see in particular Fig. 2), to form an inner opening area 10 of a plastic container 11, which in this embodiment is a preform 12 (see Fig. 2 and Fig. 3) to grasp.

[0037] The gripping device 1 or the gripping head unit 2 can be inserted into the inner opening area 10 with an axial gripping depth 15, wherein this axial gripping depth 15 is advantageously infinitely adjustable by means of the adjusting device 16 according to the invention.

[0038] For this purpose, the adjusting device 16 comprises a muzzle stop element 17 which is axially displaceable along the axial displacement axis 8, against which the frontal limit 10A (see Fig. 2 and Fig. 3) of the inner muzzle area 10, in order to define the axial penetration depth 15.

[0039] The axially displaceable muzzle stop element 17 has an upper collar area 18 that runs concentrically around the axial displacement axis 8, from which four stop bar elements 19, 20, 21 and 22 extend (see Fig. 2 and Fig. 3) extend downwards.

[0040] The four stop bar elements 19, 20, 21 and 22 are also arranged concentrically around the axial displacement axis 8 of the gripping device 1 in such a way that the frontal boundary 10A of the inner opening area 10 can rest on stop surfaces 23 (numbered here only as an example) of the respective stop bar elements 19, 20, 21 and 22.

[0041] Advantageously, the gripping elements 3, 4, 5 and 6 are arranged in the circumferential direction of the gripping head unit 2 between the stop elements 19, 20, 21 and 22 which are arranged concentrically around the axial displacement axis 8 of the gripping device 1, so that in particular the gripping head unit 2 can be built very compactly.

[0042] In order to be able to quickly reposition the axially displaceable muzzle stop element 17 in the axial direction 7 on the gripping device 1 with minimal assembly and adjustment effort, and thereby to set the desired gripping depth 15, the adjustment device 16 includes in particular a self-locking fine thread 30 (see in particular Fig. 2 and Fig. 3), on which an axially displaceable muzzle stop element 17 is mounted in an axially displaceable, screwable but also self-locking manner.

[0043] The self-locking fine thread 30 is machined on one side as an external thread section (not numbered here) on a support sleeve 31 of the gripping device 1. On the other hand, it is machined on the axially displaceable muzzle stop element 17 as an internal thread section (also not numbered here).

[0044] This internal thread section is located at the level of the circumferential collar area 18 and above it, wherein a tool receiving area 32 is provided on the outside of the axially displaceable muzzle stop element 17 above the circumferential collar area 18, on which an open-end wrench tool 33 (see Fig. 4 and Fig. 5) can be attached. In this respect, the axially displaceable muzzle stop element 17 has the tool holding area 32 on its side 34 facing away from the stop strut elements 19, 20, 21 and 22.

[0045] The axially displaceable muzzle stop element 17 with its stop web elements 19, 20, 21 and 22 can be rotated about the axial displacement axis without difficulty despite the gripping elements 3, 4, 5 and 6 arranged between them, since the gripping elements 3, 4, 5 and 6 together with stop web elements 19, 20, 21 and 22 of the axially displaceable muzzle stop element 17 are rotatably arranged about an axial displacement direction 7 of the gripping device 1 in the circumferential direction of the gripping head unit 2.

[0046] Using the open-end wrench tool 33, the axially displaceable muzzle stop element 17 can be rotated relative to the carrier sleeve 31, thereby displacing the axially displaceable muzzle stop element 17 along the axial displacement axis 8. This allows the axial engagement depth 15 to be continuously adjusted.

[0047] Setting the axial engagement depth 15 in a defined manner is extremely easy, since the adjusting device 16 includes an adjusting sleeve element 35 that can be temporarily attached to the gripping device 1.

[0048] Each adjusting sleeve element 35 has a predetermined length 36 (see Fig. 4) from which the desired axial engagement depth 15 results when the adjusting sleeve element 35 is properly fixed to the gripping device 1 by means of a transverse pin element 40 located in the upper third 37 of the carrier sleeve 31.

[0049] The cross pin element 40 serves, in the operating state of the gripping device 1, to fasten the gripping device 1 to a gripping or transport device (not shown here).

[0050] In order to make it particularly easy for the cross pin element 40 to fix or hold the properly fixed adjustment sleeve element 35, the adjustment sleeve element 35 is equipped with a corresponding bayonet device 41 into which the cross pin element 40 can snap into place in a manner known per se of a bayonet lock.

[0051] If the adjusting sleeve element 35 is correctly positioned, the axially displaceable muzzle stop element 17 can be rotated using the open-end wrench tool 33 and moved towards the underside 42 of the adjusting sleeve element 35. Once the desired axial engagement depth 15 has been set accordingly, the adjusting sleeve element 35 can be removed again from the gripping device 1 or from its carrier sleeve 31.

[0052] Furthermore, the gripping device 1 includes an actuating unit 50 for radially extending or engaging the gripping elements 3, 4, 5 and 6. The actuating unit 50 comprises a switching shaft element 52 pre-tensioned by means of disc springs 51, which can be moved within the carrier sleeve 31 in axial displacement direction 7 by means of an external switching cam (not shown here), such as a temperature control device like an oven.

[0053] In the lower end area 53 of the gripping head unit 2, a pressure plate element 54 is provided, on which a spiral spring element 55 is supported, which in turn interacts with the switching shaft element 52.

[0054] The shift shaft element 52 has release chamfers 56 (numbered only as an example), which are provided concentrically around the shift shaft element 52. The release chamfers 56 correspond to counter chamfers 57, which are formed on the inside of the respective gripping elements 3, 4, 5, and 6.

[0055] The spiral spring element 55, which is supported on the pressure plate element 54, pushes the switching shaft element 52 axially upwards, causing the gripping elements 3, 4, 5 and 6 to be disengaged radially 9 outwards, as their counter-beams 57 slide along the disengagement bevels 56.

[0056] Only when the switching shaft element 52 is actuated from the actuation direction 58 are the gripping elements 3, 4, 5 and 6 moved radially inwards with the help of a ring spring element 59, so that the gripping contact between the gripping device 1 and the inner mouth area 10 is eliminated.

[0057] In order to enable the individual gripping elements 3, 4, 5 and 6 to move radially inwards accordingly, the ring spring element 59 is placed concentrically around web elements 60 of the respective gripping elements 3, 4, 5 and 6.

[0058] The one in Fig. The alternative gripping device 101 shown in Figure 6 is essentially identical in construction to the gripping device 1 already described above ( Fig. 1 to 5), therefore, structurally identical and / or functionally equivalent components are provided with identical reference numerals. To avoid further repetition, only the differences are explained below, whereby the alternative gripping device 101 is additionally distinguished by the fact that the release chamfers 56, which interact with the counter-chamfers 57, are designed with ball sliding surfaces 170 and thus have a radically reduced contact area. This allows for significantly lower coefficients of friction.

[0059] It is understood that the exemplary embodiments described above are merely initial configurations of the gripping device according to the invention. The embodiment of the invention is therefore not limited to these exemplary configurations.

[0060] The applicant reserves the right to claim all features disclosed in the application documents as essential to the invention, provided that they are novel individually or in combination compared to the prior art. Reference symbol list 1 gripping device 2 Gripping head unit 3 first gripping element 4 second gripping element 5 third gripping element 6 fourth gripping element 7. axial displacement direction 8 axial displacement axis 9 radial 10 Mouth area 10A front-side limit 11 plastic containers 12 Preform 15 axial penetration depth 16 Adjustment device 17 axially displaceable muzzle stop element 18 surrounding collar area 19 first stop bar element 20 second stop bar element 21 third stop element 22 fourth stop bar element 30 self-locking fine thread 31 Carrier sleeve 32 Tool holding area 33 Open-end wrench tool 34 opposite side 35 Adjustment sleeve element 36 Length 37 upper third 40 cross pin elements 41 Bayonet fitting 42 Underside 50 Actuating units 51 disc springs 52 Switching shaft element 53 End range 54 Pressure plate element 55 Spiral spring element 56 release angles 57 counterslopes 58 Direction of action 59 Ring spring element 60 bridge elements 101 Gripping device 170 ball bearing surfaces

Claims

[1] Gripping device (1; 101) for gripping an inner opening area (10) of a plastic container (11), in particular a preform (12) of such a plastic container (11), with a gripping head unit (2) having an axial gripping depth (15) for at least partial axial insertion into the inner opening area (10), wherein the gripping head unit (2) comprises gripping elements (3, 4, 5, 6) which are arranged radially (9) outwards against an inner surface of the inner opening area (10) on the gripping device (1; 101) for gripping the inner opening area (10), characterized by , that the gripping device (1) has a transverse pin element (40) which, in the operating state of the gripping device (1), serves to fasten the gripping device (1) to a transport device and the transverse pin element (40) is located in the upper third (37) of a carrier sleeve (31). [2] Gripping device (1; 101) according to claim 1, characterized by, that the gripping head unit (2) has a diameter tolerance field of + / -0.9 mm in the radial release direction (9) of the gripping elements (3, 4, 5, 6), wherein the gripping elements (3, 4, 5, 6) are arranged to be radially (9) disengaged depending on a translational actuation direction (58) along an axial displacement axis (8). [3] Gripping device (1; 101) according to at least one of the preceding claims, characterized by , that the gripping device (1) has an actuating unit (50) for radially extending or engaging the gripping elements (3, 4, 5, 6). [4] Gripping device (1; 101) according to the preceding claim, characterized by , that the actuating unit (50) comprises an axially spring-loaded switching shaft element (52). [5] Gripping device (1; 101) according to the preceding claim, characterized by, that the switching shaft element (52) is arranged to be axially displaceable within a carrier sleeve element of the gripping device (1; 101). [6] Gripping device (1; 101) according to at least one of the preceding claims, characterized by , that the gripping device (1; 101) has an engagement device for radially engaging the individual gripping elements (3, 4, 5, 6). [7] Gripping device (1; 101) according to at least one of the preceding claims, characterized by , that the gripping device (1; 101) has a bayonet fitting. [8] Gripping device (1; 101) according to the preceding claim, characterized by that the bayonet fitting has a radial retaining pin.

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