WO1987001569A1

WO1987001569A1 - A method and apparatus for the separation of articles in a web

Info

Publication number: WO1987001569A1
Application number: PCT/SE1986/000408
Authority: WO
Inventors: Claes Hedlund
Original assignee: Claes Hedlund
Priority date: 1985-09-18
Filing date: 1986-09-12
Publication date: 1987-03-26
Also published as: DK230987D0; DK230987A; SE8504324D0

Abstract

A method of separating from one another plastic bags included in a web, the bags being mutually defined by openings and perforations and being rolled up to a reel, comprises the steps that the outermost bag is withdrawn against the action of a pre-tensioning force, and that the edge of the opening located most proximal the end is brought into non-symmetrical engagement with a stop, whereafter the bag is released such that the web returns towards the reel under the action of the pre-tensioning force, the outermost bag being held captive and separated along the perforation. An apparatus for carrying out the method comprises a holder (11) with a vertical shaft (12) for the reel. A spring (13) is connected to the holder (11) and the reel. The holder is provided with a stop (14) spaced from the shaft (12) and placed asymmetrically in relation to the centre of the reel, the stop being provided with two shanks (15, 16) which form a space closed towards the reel. Furthermore, the holder (11) is provided with a braking spring (17) which is intended to abut against the periphery of the reel and damp the rotation of the reel.

Description

A METHOD AND APPARATUS FOR THE SEPARATION OF ARTICLES IN A WEB.

TECHNICAL FIELD

The present invention relates to a method of separating from one another individual articles in a web, for example, plastic bags, these being rolled to form a reel and being defined in the web by means of perforations, openings in the web being provided in asso- ciation with the perforations.

The present invention also relates to an apparatus for carrying out the above-intimated method, this apparatus including support means intended for the reel and provided with shaft means about which the reel may be rotated. BACKGROUND ART

Plastic bags united to form continuous webs which are rolled up to compact reels have been widely used in the packaging of different items such as foods. As a rule, the plastic bags making up the web have been separated by means of a transverse perforation which con- stitutes an indication of rupture when the outermost bag is to be separated from the rest of the web.

Reels of this type have often been placed in particularly de¬ signed holders in shops, supermarkets and the like in immediate as¬ sociation with the foods which are to be packed in the bags. In such an instance, ^" the bag holder has been provided with a rupture or tearing edge across which the bag must be drawn on its withdrawal from the reel. In the central region of this rupture edge, there has normally been disposed a catch directed obliquely towards the reel which has penetrated the perforation of the passing web so that it has been possible to extract only the outermost bag of the web in that the perforation is ruptured.

However, with the introduction of new types of bags provided, along their edges, with tying or carrying handle strip sections, the above-described prior Art solution does not function satisfactorily, since, on withdrawal and separation of the outermost bag, the trac¬ tive force required for rupturing the perforation must be trans¬ mitted via the tying or carrying sections. These are, namely, so weak that any real concentration of force to initiate the rupture of the perforation cannot be brought about, but instead the tying or carrying sections will be stretched and deformed in order that the perforations may be subjected to an even force loading throughout their entire length. The result has been instead that the bag has been torn in a completely uncontrollable position, which often ren¬ ders the bag unusable, or at least unsuitable for its purpose. OBJECT OF THE INVENTION

Thus, the object of the present invention is to obviate the above-considered drawbacks and to realise the method intimated by way of introduction, and the apparatus intended for carrying out the method, in such a manner that a simple, easy and reliable separation of the outermost article in the web can always be guaranteed, with¬ out the necessity that the apparatus intended herefor be either ex¬ pensive or complicated. SOLUTION

This object is attained according to the present invention if the method intimated by way of introduction is characterised in that the outermost article is withdrawn from the reel, that a force counter-directed to the direction of withdrawal is applied to the reel or the web, that the web, with the edge of that opening located most proximal the outermost article, is brought into engagement with a stop, and that the web, under the action of the force counter- directed to the direction of withdrawal, is caused to return towards the reel, the outermost article being, by means of the engagement with the stop, separated from the web. In one advantageous embodiment of the present invention, the method is also characterised in that the stop is brought into en¬ gagement with the edge of the opening in a position which is asym¬ metric in relation to the longitudinal centre line of the web, the perforations being substantially transversely directed thereto.

The object of the present invention is also attained in respect of the apparatus, if this apparatus is characterised by a pivot de¬ vice which is connected to the support member and the reel, and which is disposed, on withdrawal of the web, to generate a force counter-directed to the direction of withdrawal, and by a stop which is disposed for engagement with the edge of that opening which is located most proximal the end of the web when the web has been with¬ drawn with this opening past the stop and subsequently permitted to return under the action of the pivot device. One preferred, embodiment of the apparatus according to the pre¬ sent invention is also characterised in that the stop is placed as- ymmetically in relation to the longitudinal centre line of the web.

It also further suitably applies in this embodiment that the stop is provided with two shanks making an angle with one another and forming therebetween a cuneiform nip closed towards the reel.

In one particularly advantageous embodiment of the apparatus according to the present invention, it applies to the pivot device that this consist of a spring which is interiorly disposed in the shaft member designed as a tube, the spring being, with its one end, non-rotationally connected to the support member and, with its other end, being non-rotationally connected to the reel.

Further advantages will be attained if the present invention is given any one or more of the characterising features as set forth in Claims 7 to 10. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The nature of the present invention and its aspects will be more readily understood from the following brief description of the accompanying Drawings, and discussion relating thereto. In the accompanying Drawings: Fig. 1 is a top plan view of the outer part of a web with continuous, united articles and a part of the web rolled up to a reel; Fig. 2 shows a first embodiment of an apparatus for se¬ paration of the articles included in the web; Fig. 3 illustrates a modified embodiment of the ap¬ paratus of Fig 2; and Fig. 4 schematically illustrates the cooperation between the apparatus of Fig. 2 and the web. DESCRIPTION OF PREFERRED EMBODIMENT

Referring to the Drawings, Fig. 1 shows a web which, in its left-hand end, is rolled up to form a reel 1 and, in its right-hand end, displays three different articles in the form of plastic bags 2 which, by means of perforations 3, are defined and demarcated one from the other. The web 4, which forms the different articles 2 or plastic bags, is in the form of a hose, and the different plastic bags 2 are delimited from one another by means of transverse welds 5 and 6, respectively. It will also be apparent from this Figure that openings 7 are disposed in the central region of the web 4 in im¬ mediate association with the perforations 3. It will be further ap¬ parent that, on either side of the openings, there are formed tying or carrying sections 8. It should also be noted that that edge 9 of the openings 7 located most proximal the free end of the web lies in register with perforations 3.

For certain reasons, the web 4 must be-rolled up in the manner as is apparent from Fig. 1, since, if the opposite rolling direction were selected (in other words such that the bottoms of the bags 2 were turned to be presented towards the outer end of the web), air would be forced into the bags on winding of the web 4 on the reel 1, such that it would be impossible to make the reel 1 compact.

Fig. 2 illustrates a first embodiment of an apparatus for sepa¬ ration of the plastic bags 2 making up the web. The apparatus is provided with a frame post 10 which, with its bottom end, may be fixedly anchored in, for example, a fruit counter or the like in a supermarket. Two support members or plates 11 projecting in opposite directions are fixedly mounted on the post 10. These plates are in the form of L-shaped bent sheet metal strips whose longitudinal shanks are vertical and are fixedly retained in the post. The shorter shanks are substantially horizontal and serve, at a slight distance from the support post 10, the purpose of anchorage means for approximately vertical shaft members or tubular sleeves 12 on which the reels 1 are slid down from above so that they come to rest with their lower short end against the horizontal surfaces of the support plates. The distance between the tubular sleeves 12 and the frame post 10 is selected such that reels of suitable diameter may be placed on the support plates without coming into contact with the vertical shank of the plate.

Interiorly in the tubular sleeves 12, there are disposed pivot devices in the form of tightly wound helical springs which, with their lower ends, are non-rotationally connected to the tubular sleeves 12 or the support members 11 and which, with their upper ends, protrude up above the tubular sleeves. In their upper ends, the springs are provided with protruding engagement members 13 which, in one advantageous embodiment, may be designed as a wire loop which lies in a longitudinal diametric plane of the spring and which may be passed into a slot in an end wall in the bobbin of the reel 1 or into a special make-up piece. Anchorage of the bottom end of the spring in the support member 11 may be effected by means of a construction which is identical with the wire loop 13, i.e. there is provided a slot in the support member 11 which accommodates a cor¬ responding wire loop on the bottom end of the spring.

The subject matter of the present invention further comprises a stop 14 which is fixedly anchored with one end .in the frame post 10 or the support member 11 and, in the opposite end, is provided with two shanks 15 and 16 making an angle with one another. The two shanks 15 and 16 form a wedge-shaped nip which is closed in a di¬ rection towards the tubular sleeve 12. In the axial direction along the tubular sleeve 12, the stop 14 is placed asymmetrically in re¬ lation to the centre line of the web 4 or, more precisely, in such a manner as to engage with the upper end of the edge 9 of the opening 7.

Furthermore, there is provided, at the bottom end of each tubu¬ lar sleeve 12,^" a brake device 17 in the form of a spring of metal or plastic which is intended to abut under spring force against the periphery of the reel 1. Fig. 4 illustrates the right-hand section of the apparatus ac¬ cording to Fig. 2, seen from the front and with a reel 1 mounted in place.

When the reel 1 is mounted on the tubular sleeve 12, the entire web 4 is wound up on the reel so that only the tying sections 8 are free. In this position, the reel is brought into non-rotational en¬ gagement with the spring disposed interiorly in the tubular sleeve so that, on withdrawal of the web from the reel, the spring will hereby be subjected to torsion, whereby there is generated, in the spring, a force which is counter-directed to the direction of with¬ drawal of the web. If the web, in the partly withdrawn state, for example as shown in Fig. 4, is released, the spring disposed inter¬ iorly in the tubular sleeve 12 will retract the withdrawn web so that the outermost tying section 8 will arrive at a position in at the reel. If the web is released in this manner, the brake device 17 is employed to prevent the reel from continuing to rotate too far past its position of rest.

In the employment of above-described embodiment of the present invention, it will be assumed that the web is rolled up on the reel 1 such that only the tying sections 8 are readily accessible. When one such tying section is grasped and the web is withdrawn in a tan¬ gential direction, the spring disposed interiorly in the tubular sleeve 12 will be placed under tension, whereby a force is built up which is counter-directed to the direction of withdrawal. However, withdrawal is continued so far that that opening 7 which is located most proximal the free end of the web will move past the stop 14 and its two shanks 15 and 16, at least with the edge 9. Thereafter, the web is possibly pivoted so that the edge 9 may be moved in between the two shanks 15 and 16, whereafter the web is quite simply re- leased or is permitted to return under the action of the energy stored in the pivot device or the spring disposed interiorly in the tubular sleeve 12. As a result, the stop 14 will enter into engage¬ ment with the upper end of the edge 9, in other words immediately adjacent the lower edge of the perforation 3 at the upper tying sec- tion 8. The movement in the returning web 4 will, in this instance, give rise to a point loading against the lower end of the per¬ foration 3 at the upper tying section 8, so that this perforation begins to rupture under the action of the force generated from the pivot device. The edge 9 will, here, be fixedly clamped between the two shanks 15 and 16, such that the outermost bag is held captive in the stop 14. On continued retraction of the web, the lower perfor- ation 3 will also be subjected to a point loading at its upper end, such that this perforation will also thereby be ruptured under the action of the force generated by the pivot device. The outermost bag 2 is now completely disengaged from the web 4 and may possibly be retained in the stop 14 while the web is retracted onto the reel 1. It will be apparent from Fig. 2 that the stop .14 is bent in such a manner as to be located, for the greater part, behind the tubular sleeves 12 (seen from the direction of the user) and, conse¬ quently, also behind the reels 1. This entails that the web 4 is withdrawn obliquely forwardly towards the user, and that the web is subsequently moved either to the right or to the left into engage¬ ment with the stops 14. DESCRIPTION OF ALTERNATIVE EMBODIMENTS

The embodiment illustrated in Fig. 3 is constructed, in prin¬ ciple, in the same manner as the embodiment according to Fig. 2, but it should here be observed that the stops 14 are placed in a dif¬ ferent manner and are also bent differently than is the case ac¬ cording to Fig. 2. This embodiment can, thus, be considered as double-sided in which the webs are suitably withdrawn in the longit¬ udinal direction of the two shanks 18 of the stops 14. The apparatus according to the present invention has been de¬ scribed above as placed on a frame post 10. According to the inven¬ tion, this is by no means necessary; the apparatus can instead be placed on a wall bracket of any suitable design. Nor need the appar¬ atus be of the double track construction as illustrated in Figs. 2 and 3, but may, of course, just as well be of single track cons¬ truction.

It has been intimated above that the reel 1 may be provided with a make-up piece which, in its turn, engages with the upper end of the pivot device, in other words with the wire loop 13. This make-up piece is in the form of an approximately cylindrical or very gently conical tube which, at its lower end - as intimated in Figs. 1 and 4 - is provided with a flange 19 which abuts against the upper upper face of the support member 11 and may be considered as con¬ stituting an axial bearing for the reel, such that the reel is ex¬ posed to an even, and more or less constant, friction. Furthermore, the make-up piece is designed in such a manner as to be insertable with tight fit into the bobbin of the reel so that any anxiety con¬ cerning relative rotation between the reel and the make-up piece may thereby be discounted. Possibly, the make-up piece may, along its outer circumferential surface, be provided with a number of longitu¬ dinal ribs or projections which improve the non-rotational inter- connection between the reel 1 and the make-up piece.

At the upper end of the make-up piece, there is provided a transverse wall which may possibly be downwardly displaced a dis¬ tance in the tubular sleeve of the make-up piece, but which, under any circumstances, is provided with a slot-like aperture for acco - modating the wire loop 13. *

Suitably, the make-up piece is interiorly dimensioned in such a manner as to be easily rotatable about the tubular sleeve 12, but substantially without play.

In^' one alternative to the above-described make-up piece, the reel 1 may be provided with a transverse wall directly anchored in its bobbin, and provided with the necessary slot-like aperture for cooperation with the wire loop 13.

As an alternative to the above-described brake device 17, a flap is also conceivable which is pivotal in the upper end of the support member 11 and which abuts against the upper end surface of the reel 1. Such a flap may be given the function of a brake device and may also be employed to prevent the reel 1 from being raised to such a height - as a result of careless handling - that engagement with the wire loop 13 is lost. Naturally, such a flap may be spring- -biased downwardly or, preferably, be fixedly lockable so that it cannot be raised further than is intended.

If the flap is fixedly lockable in the vertical direction, it may suitably be provided on its underside with resiliently yieldable brake means for abutment against the reel 1. It has been intimated above that one stop 14 should be provided for each reel 1. However, for reasons of convenience, it may be ap¬ propriate to provide two stops 14 for each reel, one on either side of the web 4, so that the user withdrawing the web from the reel, preferably towards his person, may choose between moving the edge 9 into engagement with the stop on the left or on the right side of the web.

The present invention should not be considered as restricted to that described above and shown on the Drawings, many modifications being conceivable without departing from the spirit and scope of the appended Claims.

Claims

1. A method of separating from one another individual articles (2), for example plastic bags, included in a web (4), the articles being rolled up into a reel (1) and being defined in the web by per¬ forations (3), there being provided, in association with the per- forations, openings (7) in the web, characterised in that the outer¬ most article is withdrawn from the reel (1); that a force counter- directed to the direction of withdrawal is applied against the reel or the web (4); that the web is brought, with that edge (9) of the opening located most proximal the outermost article, into engagement with a stop (14); and that the web, under the action of the force counter-directed to the direction of withdrawal, is caused to return towards the reel, the outermost article (2) being separated from the web by engagement with the stop.

2. The method as claimed in claim 1, characterised in that the stop (14) is brought into engagement with the edge (9) of the op¬ ening (7) in a position which is asymmetric in relation to the long¬ itudinal centre line of the web (4), the perforations (3) being sub¬ stantially transversely directed thereto.

3. An apparatus for separating from one another individual ar- tides (2), for example plastic bags, included in a web (4), the ar¬ ticles being rolled up into a reel (1) and being defined in the web by perforations (3), there being provided, in association with the perforations, openings (7) in the web, and including a support mem¬ ber (11) with a shaft means (12) about which the reel is rotat- able, characterised by a pivot device which is in connection with the support member (11) and the reel (1), and which is operative, on withdrawal of the web (4), to generate a force counter-directed to the direction of withdrawal, and a stop (14) which is disposed for engagement with the edge (9) of that opening (7) which is located most proximal the end of the web (4) when the web has been with¬ drawn, with this opening, past the stop and has subsequently been permitted to return under the action of the pivot device.

4. The apparatus as claimed in claim 3, characterised in that the stop (14) is placed asymmetrically in relation to the longitu¬ dinal centre line^'of the web (4).

5. The apparatus as claimed in claim 3 or 4, characterised in that the stop (14) is provided with two shanks (15, 16) making an angle with one another and forming therebetween a cuneiform nip space closed towards the reel (1).

6. The apparatus as claimed in anyone of claims 3 to 5, charac¬ terised in that the pivot device consists of a spring which is dis- posed interiorly in the shaft means (12) designed as a tube, the spring, with its one end, being non-rotationally connected to the support member (11), and with its other end (13) being non- rotationally connected to the reel (1).

7. The apparatus as claimed in claim 6, characterised in that the spring is a helically wound spring which, at each end, has en¬ gagement means (13) for the non-rotational engagement with the sup¬ port member (11) and the reel (1), respectively.

8. The apparatus as claimed in anyone of claims 6 or 7, charac¬ terised in that the reel (1) is non-rotationally connected to a make-up piece which acts as a bearing for the reel in relation to the shaft means (12) and which is provided with an engagement member designed for the non-rotational cooperation with the spring.

9. The apparatus as claimed in anyone of claims 6 or 7, charac¬ terised in that the reel (1) is provided with engagement means for the non-rotational connection with the spring.

10. The apparatus as claimed in anyone of claims 3 to 9, charac¬ terised by a brake device (17) for braking the rotational movements of the reel (1).