EXTRUSION-BLOW-MOULDING METHOD AND DEDICATED ROBOT

Abstract

Some embodiments are directed to an extrusion blow-molding method for the manufactures of blown objects with at least one label integrated in situ, and also including a robot implementing this method.

Claims

1. An extrusion blow-molding method comprising: extruding at least one parison in an extrusion direction, closing a first clamp including a first mold around the parison in a first clamping direction perpendicular to the extrusion direction, wherein at least one cavity of the first mold contains at least one sheet, and the first clamp picks up again at least one first blown object retained by at least one first blow pipe, transferring the first clamp in a first transfer direction inclined with respect to the extrusion direction, and perpendicular to the first clamping direction along a first level, inserting the first blow pipe on one end of the parison to blow it in the first mold, and form at least one second blown object, the sheet being integrated into the second blown object, and opening the first mold in the first clamping direction, and retaining the second object on the first blow pipe, and releasing the first blown object on a first discharge system, wherein, during the step of extruding the parison, when the first mold is opened, the first blown object (4a) is transferred by the first blow pipe from the first level to a second level offset with respect to the first in the extrusion direction, the sheet is placed in the cavity of the first mold by first insertion means, then the first clamp is transferred in the first transfer direction to place the first mold around the parison, and in that the first clamp picks up again the first blown object at the second level during the step of closing the first clamp to transfer it to the first discharge system.

2. The extrusion blow-molding method according to claim 1, further comprising: in a second open mold, maneuvered by a second clamp, at least one third blown object is transferred by at least one second blow pipe from the first level to the second level, at least one second sheet is placed in at least one cavity of the second mold by second insertion means, the second clamp is transferred in the second transfer direction to place the second mold around the parison when the first clamp is withdrawn, and the second mold is closed around the parison in a second clamping direction perpendicular to the extrusion direction, and the second clamp picks up again the third blown object retained by the second blow pipe at the second level, the second clamp is transferred in a second transfer direction inclined with respect to the extrusion direction, and perpendicular to the second clamping direction, the second blow pipe is inserted on one end of the parison to blow it in the second mold, and form at least one fourth blown object, the sheet being integrated into the fourth blown object, and the second mold is opened in the second clamping direction while retaining the fourth blown object on the second blow pipe, and the third blown object is released on a second discharge system.

3. The extrusion blow-molding method according to claim 1, wherein the first or the second transfer direction is perpendicular to the extrusion direction.

4. The extrusion blow-molding method according to claim 3, wherein the first and the second transfer direction are parallel.

5. The extrusion blow-molding method according to claim 1, according to which the parison is cut transversely during the closure of the mold.

6. A robot for an extrusion blow-molding machine, comprising: a first clamp including a first mold for closing the first mold around at least one parison extruded by an extrusion head in an extrusion direction, the first mold including shells with cavities, the shells being movable in a first clamping direction perpendicular to the extrusion direction, the first clamp further including first gripping means for picking up again at least one first blown object retained by at least one first blow pipe, first insertion means for inserting at least one sheet to the surface of at least one of the cavities, first transfer means for transferring the first clamp in a first transfer direction inclined with respect to the extrusion direction, and perpendicular to the first clamping direction along a first level, the first blow pipe being capable of being inserted on one end of the parison to blow it in the first mold, and form at least one second blown object, the sheet being integrated into the second blown object, and capable of retaining the second object on the first blow pipe during the opening of the first mold by the first clamp, and a first discharge system positioned to receive the first blown object by the first gripping means during the opening of the first clamp, wherein the first blow pipe is arranged for transferring the first blown object from the first level to a second level offset with respect to the first in the extrusion direction so as to remove the first blown object from the first mold, in that the first insertion means are arranged for inserting the sheet facing the first blow pipe, in that the first gripping means are arranged for picking up again the first blown object at the second level during closure of the first clamp to transfer it to the first discharge system, and in that the robot is controlled so as to implement the method according to claim 1.

7. The robot according to claim 6, further including: a second clamp including a second mold for closing the second mold around the parison in a second clamping direction perpendicular to the extrusion direction, the second mold including shells with cavities, and second gripping means for picking up again at least one third blown object retained by at least one second blow pipe, second insertion means for inserting at least one sheet to the surface of at least one of the cavities of the second mold, second transfer means for transferring the second clamp in a second transfer direction inclined with respect to the extrusion direction, and perpendicular to the second clamping direction along the first level, the second blow pipe being capable of being inserted on one end of the parison to blow it in the second mold, and form at least one fourth blown object, the sheet being integrated into the fourth blown object, the second blow pipe being capable of retaining the fourth object on the second blow pipe during the opening of the second mold by the second clamp, and arranged to transfer the fourth blown object from the first level to the second level (B), and a second discharge system positioned to receive the third blown object by the second gripping means during the opening of the second clamp, the second gripping means being arranged to pick up again the third blown object at the second level during the closure of the second clamp to transfer it to the second discharge system, the robot being controlled so as to implement the method according to claim

Description

BRIEF DESCRIPTION OF THE FIGURES

[0055] The invention will be better understood and other features and advantages will appear upon reading the description that follows, the description referring to the appended drawings wherein:

[0056] FIG. 1 is a schematic view of an extrusion blow-molding installation according to the prior art at a station with means for inserting sheets;

[0057] FIGS. 2a to 2h show the steps of a method implemented by the installation of FIG. 1;

[0058] FIG. 3 shows another installation according to the prior art, with two blow-molding stations;

[0059] FIG. 4 shows another installation according to the prior art, with two blow-molding stations and means for inserting sheets;

[0060] FIG. 5 is a schematic view of an extrusion blow-molding installation at a station with means for inserting sheets according to a first embodiment of the invention;

[0061] FIGS. 6a to 6i show the steps of a method implemented by the installation of FIG. 5;

[0062] FIG. 7 is a schematic view of an extrusion blow-molding installation with two stations with means for inserting sheets according to a second embodiment of the invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0063] Referring to FIGS. 5 and 6a to 6i, an extrusion blow-molding installation includes an extruder whereof only the head 1 is shown in the figures, and a robot 2 according to a first embodiment of the invention. The extrusion head 1 continuously produces a parison 3 of tubular shape in an extrusion direction F1, in this case vertically downward. The robot 2 includes a first clamp 11 including a first mold 111 to close the first mold 111 around the parison 3. The first mold 111 includes shells 1111 with cavities 1112. The shells 1111 are movable along a first clamping direction F2 perpendicular to the extrusion direction F1, i.e. horizontally.

[0064] The robot 2 further includes first transfer means, not shown, to transfer the first clamp 11 in a first transfer direction F3 between the extrusion head 1 and a first blow-molding station along a first level A. The first transfer direction F3 can for example be inclined with respect to the extrusion direction F1 and perpendicular to the first clamping direction F2. In this case, the first transfer direction F3 is perpendicular to the extrusion direction F1, and therefore horizontal.

[0065] The first clamp 11 further includes first gripping means 112 to pick up again a first blown object 4a and transfer it, in a manner detailed hereafter.

[0066] The robot 2 includes at the blow-molding station a first blow pipe 13 slidably mounted in the extrusion direction F1. The first blow pipe 13 is capable of being inserted, in a blow-molding position, on one end of the parison 3 at the first blow-molding station to blow it in the first mold 111 and form a second blown object 4b. The first blow pipe 13 is further capable of holding the second blown object 4b to bring it to a second level B higher than the first level A so as to remove the second blown object 4b from the first mold 111.

[0067] The robot 2 further includes first insertion means 14 for inserting a sheet 5 to the surface of each of the cavities 1112 when the first mold 111 is at the blow-molding station, in the open position. The first insertion means 14 includes two arms 141 slidably mounted, each arm 141 terminated by a gripping device 142 capable of supporting and transporting one of the sheets 5 for presenting it facing the corresponding shell 1111. The arm 141 or the gripping device 142 is further capable of moving in the clamping direction to deposit and transfer the sheet 5 on the shell 1111 in the cavity 1112, in a manner known per se. In the case of depositing the sheet in only one of the shells, only one arm may be used.

[0068] The robot 2 also includes a first discharge system 15 positioned for receiving the first blown object 4a by the first gripping means 112 during the opening of the first clamp 11.

[0069] The robot 2 is controlled, for example by a programmable logic controller, not shown, to implement the method which will now be described.

[0070] In an initial position, shown in FIG. 6a, the parison 3 is being extruded. The first mold 111 is closed and the first clamp 11 is at the blow-molding station. The first blow pipe 13 is engaged in the first mold 111 which contains the second blown object 4b. The first gripping means 112 hold by a neck the first blown object 4a above the first discharge system 15.

[0071] In the first step, shown in FIG. 6b, the first clamp 11 opens in such a manner that the second blown object 4b is released from the first mold 111 while being held on the end of the second blow pipe. The first gripping means 112 release the first blown object 4a which is thus transferred to the first discharge system 15.

[0072] In the second step, shown in FIG. 6c, the first blow pipe 13 transfers the second object from the first level A to the second level B.

[0073] In the third step, shown in FIG. 6d, the first insertion means 14 insert two sheets to place them respectively in the cavities 1112 of the two shells 1111 of the first mold 111, and deposit them.

[0074] In the fourth step, shown in FIG. 6e, the first insertion means 14 withdraw.

[0075] In the fifth step, shown in FIG. 6f, the transfer means move the first clamp 11 to place the first mold 111 around the parison 3, while the sheets are held in the shells 1111.

[0076] In the sixth step, shown in FIG. 6g, the first clamp 11 is closed so as to insert the parison 3 into the first mold 111. In the same movement, the first gripping means 112 seize the second blown object 4b by the neck, in proximity to the connection with the first blow pipe 13.

[0077] In the seventh step, shown in FIG. 6h, the first blow pipe 13 moved upward to disengage from the second blown object 4b, held by the first gripping means 112.

[0078] In the eighth step, shown in FIG. 6i, the transfer means move the first clamp 11 with the second object so that the first blow pipe 13 is facing the first mold 111. At this time, the second blown object 4b is above the first discharge system 15.

[0079] In the ninth step, the first blow pipe 13 drops and blows air into the parison 3 to press the walls of the parison 3 into the cavities 1112 of the shells 1111. A third object is thus formed, bearing on its surface the sheets which were inserted into the first mold 111. The position attained is that of the initial position, except that the second object has replaced the first in the first gripping means 112. The cycle then resumes at the first step.

[0080] Another installation is shown in FIG. 7 and includes a robot 2′ according to a second embodiment of the invention. In this installation the robot 2a according to the first embodiment is complemented by a second, identical or symmetric station 2b placed facing the first station 2a. This second station 2b similarly includes a second clamp 21 including a second mold 211 for closing the second mold 211 around the parison 3. The second mold 211 includes shells 2111. The shells 2111 are movable in a second clamping direction F4 perpendicular to the extrusion direction F1, i.e. horizontally.

[0081] The robot 2′ further includes second transfer means, not shown, for transferring the second clamp 21 in a second transfer direction F5 parallel to the first transfer direction F3 between the extrusion head 1 and a second blow-molding station along the first level A.

[0082] The robot 2′ includes, at the blow-molding station, a second blow pipe 23 slidably mounted in the extrusion direction F1. The second blow pipe 23 is capable of being inserted, in a blow-molding position, on an end of the parison 3 at the blow-molding station to blow it in the second mold 211 and form a fourth blown object. The second blow pipe 23 is further capable of holding the blown object to bring it to a second level B above the first level A so as to remove the fourth blown object from the second mold 211.

[0083] The second clamp 21 further includes second gripping means 212 for picking up again a third blown object 4c retained by the second blow pipe 23 at the second level B.

[0084] The robot 2′ further includes second insertion means 24 for inserting a sheet to the surface of each of the cavities 222 when the second mold 211 is at the second blow-molding station, in the open position. The second insertion means 24 are similar to the first insertion means 14.

[0085] The robot 2′ also includes a second discharge system 25 positioned to receive the third blown object 4c by the second gripping means 212 upon opening the second clamp 21.

[0086] The second station operates like the first station, but with an offset, meaning that the closing of the second mold 211 on the parison 3 is accomplished during the blow-molding of an object in the first mold 111, and conversely. The operation will therefore not be described in more detail.

[0087] The invention is not limited to the embodiments which have just been described by way of examples. The first and the second transfer directions F3, F5 are not necessarily parallel, but can be angularly offset when viewed in the horizontal plane. Moreover, they are not necessarily horizontal and can be oriented to descend or to rise toward the blow-molding station. Other improvements commonly used in extrusion blow-molding technique can also be adopted.