WO2006031165A1

WO2006031165A1 - A method and an apparatus in the separation of plastic bodies

Info

Publication number: WO2006031165A1
Application number: PCT/SE2005/001235
Authority: WO
Inventors: Thomas Pettersson; Michael Hermansson; Ingvar Andersson
Original assignee: Tetra Laval Holdings & Finance S.A.
Priority date: 2004-09-16
Filing date: 2005-08-25
Publication date: 2006-03-23
Also published as: SE527948C2; SE0402250L; SE0402250D0

Abstract

The invention relates to an apparatus and a method for separating plastic bodies displaying a plurality of mutually sequentially disposed parts. The parts are interconnected at interface regions which display surfaces suitable for rolling. The body (1) is caused to roll along a path to a first separation station (A), an interface region (3) of the body is centred (7) and rolled over a separator device (8) dividing the body in the interface region (3) forming two part groups, the part groups are caused to roll along the path to a second separation zone (B), an interface region (3) at each part group is centred and caused to roll each over a separator device (8) separating said part groups into new smaller part groups or freely exposed and separated parts, and this stepwise separation of the part groups is repeated until all parts have been freely exposed.

Description

A METHOD AND AN APPARATUS IN THE SEPARATION OF PLASTIC BODIES

TECHNICAL FIELD The present invention relates to a method and an apparatus for the separation of plastic bodies displaying a plurality of sequentially disposed parts. More specifically, the invention relates to the separation of parts of such a body in which the parts are interconnected at interface regions which display surfaces suitable for rolling.

BACKGROUND ART

There are numerous different types of packages for different contents available on the market. For example, these packages may be manufactured from laminated paperboard with or without barrier properties, depending upon the product for which the packages are intended.

It is becoming increasingly common to provide such packages with portions or arrangements, for example opening arrangements, which consist wholly or partly of plastic material.

These portions or arrangements of plastic material may be produced in different ways. One method is to form blanks or bodies which are then divided up into the contemplated parts. Such bodies normally display a plurality of sequentially arranged and continuously disposed parts.

One example of a body produced by extrusion and subsequent blow moulding is described in EP 0 960 014. The body displays a plurality of tops intended for a package, the tops being disposed in sequence. The tops are mutually interconnected, alternatingly via neck-to-neck and edge portion-to-edge portion. Further, it is disclosed that the body is to be separated into so-called double tops and that the double tops are separated from one another at the necks by means of "a rotary cutter" of known type. On the separation of a body into parts, it is important that this take place rapidly and rationally. It is also important to maintain precision in the positioning of the separation incision. In addition, it is often important that the resulting incision surfaces be even, in particular if the incision surface is later intended to be free. These desires and needs in the art may often be perceived as contradictory and difficult to reconcile.

SUMMARY OF THE INVENTION

The object of the present invention is to realise a method and an apparatus which realises, in an efficient and reliable manner, the separation of a body displaying a plurality of parts disposed in a row and interconnected at interface areas displaying rolling surfaces disposed at a constant radial distance in relation to their respective centres of rotation.

This object is attained by means of a method or an apparatus as set forth in the appended independent Claims.

The method according to the present invention comprises the following steps:

An interface region of the body is caused to roll along a path to a first separation station A where the interface region is centred and rolled over a separator device which divides the body in the interface region and forms two groups of parts.

Thereafter, the groups of parts are caused to roll along the path to a second separation zone B where one interface region at each group of parts is centred and each caused to roll over a separator device which separates these groups of parts into new, smaller groups of parts; and that this stepwise separation of groups of parts is repeated until the desired result has been attained and all parts have been exposed.

In order further to increase efficiency, separate groups of parts may be rolled in parallel along the path and the centremost interface region of the body and later the groups of parts, or the interface region of the body and later the groups of parts disposed most proximal the centre, is that interface region which is caused to roll over the separator device. Hereby, it will be possible to keep the number of requisite separation zones to a minimum even though only a single interface region at the individual group of parts is centred and separated in each separation zone.

The groups of parts may further advantageously be mutually displaced axially, transversely of the direction of the path in connection with separation, in order to realise an axial clearance between the groups of parts. This clearance fulfils a function in the subsequent separation. If, for example, a knife or similar cutting device which requires space and does not remove material is employed, an axial displacement of newly separated groups of parts will be required. Such a separation method is to be preferred, since, unlike a separation which removes material, it does not create dust or burring. Examples of methods of separation which do not remove material are knives (with or without heating, rotary or stationary), laser beams, hot wires, etc.

The apparatus according to the present invention comprises a path with support surfaces against which the interface regions of the body may abut. Carriers are further provided for rolling the body along the path to a first separation zone A, where the carrier is disposed to apply at least one interface region against its support surface. In the separation zone, there is a separator unit comprising, at least one guide means for receiving and centring an interface region and, on the other hand, a separator device for separating the centred interface region which is rolling over the separator device and forms two groups of parts. In the direction of operation of the path, after the introductory separation zone, there is provided a second separation zone B displaying two separator units for continued separation of the groups of parts.

In the second separation zone B, there may be provided two separator units for simultaneous separation of the now two groups of parts. Also here, carriers are provided for rolling the groups of parts and applying at least one interface region at each group of parts against the associated support surface, at least that interface region which is rolled through the separator unit being applied.

A plurality of separation zones may subsequently be provided after one another along the path. At separation zone lettered Z, there are preferably provided 2^Z4 number of separator units. In order that the apparatus, in addition to being efficient in operation, will also require a minimum of space, the path may advantageously be upwardly curved and preferably endless, which saves floor space. For example, the path may be disposed interiorly in a cylindrical structure displaying an inlet for the body and outlet for separated parts, as well as carriers which are pivotally disposed about a central pivot axis in the cylindrical structure.

A number of carriers corresponding to the number of interface regions of the body may be provided in a cluster or set for rolling the body through the apparatus and more than one set may be provided for the simultaneous separation of more than one body. It is further advantageous if the carriers are of continuous operation at a constant speed, which then places demands on the infeed of bodies at the inlet so that this takes place synchronised with the movement of the carriers. In addition, the outlets should be disposed to deflect the separated parts from the path without disrupting/affecting the movement of the carriers.

BRIEF DESCRIPTION OF THE DRAWINGS

One currently preferred embodiment of the present invention will now be described in greater detail hereinbelow, with reference to the accompanying drawings in which identical or similar parts have been given the same reference numeral and in which:

Fig. 1 schematically illustrates one configuration with three separation zones according to one embodiment of the present invention; Fig. 2 schematically illustrates a side elevation of one embodiment of the present invention;

Fig. 3 schematically illustrates a path configuration according to one preferred embodiment of the present invention; and

Fig. 4 schematically illustrates a skeleton side elevation of one preferred embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In the illustrated embodiment, the point of departure is a body 1 formed by blow moulding of plastic and displaying six mutually subsequent parts in the form of so-called double tops 2 which are mutually interconnected at five rotationally symmetrical interface regions in the form of the necks 3 of the double tops. Further, the body displays two end parts 4 which are connected, one to the neck of the first double top facing away from the remainder and one to the neck of the last double top facing away from the remainder. The end parts 4 are also connected to each respective neck 3 by rotationally symmetric interface regions. These end parts are also to be removed before the double tops are wholly exposed. This implies that a total of seven separation incisions are required in order that all six of the double tops in the body under consideration are to be freely exposed.

With reference to Fig. Ia, the body 1 is placed in a path with its longitudinal axis transversely of the direction of the path. The path displays seven support beads 5 extending in the direction of the path and disposed each to receive one of the interface regions 3 which interconnect the parts 2, 4 of the body and which constitute those surfaces against which the body is to be caused to roll.

The rolling of the body proper is realised by carriers 6 which will be described in greater detail hereinbelow. These carriers apply the interface regions against the support beads and roll the body in the direction of the path towards a first separation zone A. The interface regions display a rolling surface at a predetermined distance from their centre axis. In this case, the rolling surface substantially consists of the radially outermost portions of those threads which are to be found at the necks

3 of the double tops. From this it thus follows that the rolling surface need not be in the form of a continuous surface but may also consist of one or more surfaces of lesser extent or ridges which roll against the support bead.

In the first separation zone A, the body initially meets a guide member 7 in the form of configurational changes in the abutment surface of the centremost support bead, the configurational changes being substantially complementarily formed against the profile curve which the corresponding interface region displays in order, by cooperation therewith, to align the relevant interface region before separation.

When the centremost interface region of the body is in engagement with the guide member 7, it rolls over a cutting device in the form of a cutting edge or knife 8 which extends up over the support surface and which penetrates through the material thickness in the interface region and separates the body into two parts or sections - part groups. The distance along which the knife 8 extends up over the above mentioned support surface is adapted in response to the distance which is required for the interface region to roll a complete revolution. Since the knife does not remove material but penetrates with all of its width into and separates the material, an axial displacement of the thus formed part groups will be permitted by the guide member 7. Preferably, this axial displacement will, after the separation, will be slightly larger than that required by the knife before the guide member 7 releases its control over the two groups of parts. This is in order to create space 9 for an imminent separation step.

The carriers 6 continue to roll the now two parallel part groups along the path to a second separation zone B which is schematically illustrated in Fig. Ib.

In the second separation zone B, the part groups initially each meet a guide member in the form of configurational changes 7 in the support bead which, for each respective part group, supports the centremost interface surface 3. From the left in Fig. Ib, this corresponds to the second and the sixth support bead 5. When each respective centremost interface region of the part groups is in engagement with the guide member 7, they roll over a cutting edge or knife 8 which extends up over each respective support surface and which penetrates through the interface region 3 and separates each respective part group into two sections. There are now four part groups each of two parts. Also here, an axial displacement is permitted and this is permitted after the separation to become slightly larger than that required by the knife so as to create clearance 9 before the guide member 7 releases its influence over the part groups.

In the third separation zone, the now four part groups (which only have one interface region 3 each) now each meet their guide member in the form of configurational changes 7 in the support bead which supports the interface surface 3.

From the left in Fig. Ic, this corresponds to the first, third, fifth and seventh support bead 5.

When each respective interface region 3 of the part groups is in engagement with each respective guide member 7, they roll over a cutting edge or knife 8 which extends up over each respective support surface and which penetrates through the interface region and separates the part groups into two sections each. Six double tops

2 have now been exposed and the two end parts 4 have now been removed.

With reference to Figs. 2 and 4, the path according to the present embodiment is provided as an endless path in that it is curved upwardly until it has formed a loop within a cylindrical structure.

Around the centre axis 10 of the cylindrical structure, also serving as the axis of curvature of the path, an arm 11 is adjustably pivotally disposed, at whose free end a pair 6 of wheels is disposed. The axes of rotation 13, 14 of the pair of wheels are mutually parallel and parallel with the pivot axis 10 of the arm. The axes of rotation of the pair of wheels are further mutually somewhat offset in the tangential direction in relation to the arm 11 in order to be able to accommodate between them an interface region between the parts in the body 1.

In order to ensure good abutment against the support beads and good rolling, one set of such arms 11 is disposed in parallel along the centre axis 10 of the structure. In one set, there is included an arm with one pair 6 of wheels for each interface region 3 of the body in connection with which the apparatus according to the invention is to be employed, in this case seven in number.

By non-rotationally disposing the arms included in one set at a motor-driven shaft, said arrangement constitutes the previously mentioned carriers 6.

Those wheels which are included in the pairs 6 of wheels of the carrier are here designed with a radial inner portion including a bearing and a radial outer portion of a material which is elastic in the radial direction. This is in order for the wheel, on the one hand, to be able to abut the interface region and, on the other hand, to be capable of absorbing tolerances in the radial distance of the path from the centre of rotation and in the interface region without deforming the interface region. In addition, the wheel pairs 6 are disposed so that, together with the support bead 5, they abut against the interface region at three points, mutually displaced 120° about the interface region.

A body which is to be separated is introduced into the path via an inlet to a starting position where the body is brought into engagement with a passing carrier 6 which rolls the body and its parts through the separation zones of the path to an outlet where the exposed and separated parts are led out from the path through hatches.

With reference to Fig. 4, in one preferred embodiment there may be introduced four sets of carriers 6, these sets being mutually offset through 90° about the centre axis 10. As a result, for each revolution through which the motor-driven shaft 10 rotates, four bodies 1 can be separated, which quadruples the capacity compared with the utilisation of but a single set of carriers. Naturally, it is possible to introduce additional sets of carriers if it is desired to further increase efficiency.

For efficiency, it is vital that the body or alternatively the groups of parts be separated in the middle in each separation zone and that the number of separations D which is to be carried out is preferably retrieved from the series: 1, 3, 7, 15, 31; i.e. D = m x 2 + 1, where m is a whole number.

The cylindrical configuration of the path has further drastically reduced the floor space which a separation apparatus of this type would otherwise require.

While the present embodiments have taken as their point of departure a body with double tops, it should be emphasised that the present invention has its application also in relation to other bodies where those parts which are freely exposed and separated display portions/interface regions with rolling surfaces which, in relation to their respective centres of rotation, are disposed at a constant radial distance in those regions where the separation is to be put into effect. Further, nor are the exemplified parts in the preferred apparatus restrictive of the scope of protection of the present invention, but other constructional solutions and choice of parts may be employed in order to attain the characterising features as defined by the appended

Claims.

Claims

1. A method in the separation of a plastic body (1) displaying a plurality of sequentially disposed parts (2, 4) interconnected at interface regions (3) displaying rolling surfaces disposed at constant radial distance in relation to their respective centres of rotation, characterised in that the body (1) is caused to roll along a path to a first separation station (A); that an interface region (3) of the body is centred (7) and rolled over a separator device (8) separating the body in the interface region (3) forming two part groups; that the part groups are caused to roll along the path to a second separation zone (B); that one interface region (3) at each part group is centred and caused each to roll over a separator device (8) separating said part groups into new smaller part groups or freely exposed parts; and that this stepwise separation of part groups is repeated until such time as all parts have been freely exposed.

2. The method as claimed in Claim 1, characterised in that the centremost interface region of the body or alternatively the part group or the interface region disposed most proximal the centre is caused to roll over the separator device (8).

3. The method as claimed in any of Claims 1 or 2, characterised in that separated part groups are rolled in parallel along the path.

4. The method as claimed in any of the preceding Claims, characterised in that the part groups are, in connection with the separation, mutually displaced axially, transversely of the direction of the path for realising an axial clearance (9) between the part groups.

5. An apparatus in the separation of a plastic body (1) which displays a plurality of mutually sequentially disposed parts (2) interconnected at interface regions (3) displaying rolling surfaces disposed at a constant radial distance in relation to their respective centres of rotation, comprising a path with support beads (5) against which the interface regions (3) of the body may abut, characterised in that carriers (6) are disposed to apply the interface regions against the support surfaces and roll the body (1) along the path; that a first separation zone (A) is disposed along the path, displaying a separator unit comprising, on the one hand, a guide member (7) for receiving and centring an interface region (3) and a separator device (8) for separating the centred interface region (3) which is rolling over the separator device and forming two part groups; and that there is disposed, in the direction of the path and after the introductory separation zone, a second separation zone (B) displaying two separator units for continued separation of the part groups.

6. The apparatus as claimed in Claim 5, characterised in that there are provided, in the second separation zone (B), two separator units for the simultaneous separation of the two part groups; and that there are disposed, in a third separation zone (C), four separator units for the simultaneous separation of the four part groups.

7. The apparatus as claimed in Claims 5 and 6, characterised in that a plurality of separation zones are disposed in sequence after one another along the path, there being provided, in separation zone Z, 2^2"1 separator units.

8. The apparatus as claimed in any of Claims 5 to 7, characterised in that the path is curved upwards.

9. The apparatus as claimed in any of Claims 5 to 8, characterised in that the path is disposed interiorly in a cylindrical structure displaying an inlet for the body and outlets for separated parts; and that carriers (6) are pivotally disposed about a central pivot axis (10) in the cylindrical structure.

10. The apparatus as claimed in any of Claims 5 to 9, characterised in that a number of carriers (6) corresponding to the number of transitions in the body is disposed in a set for rolling of the body through the apparatus; and that more than one set is provided for simultaneously separating more than one body; and that the carriers are preferably disposed for continuous movement.