GB1561973A - Apparatus for oepning flattened tubes of flexible sheet material - Google Patents

Description

(54) APPARATUS FOR OPENING FLATTENED TUBES OF FLEXIBLE SHEET MATERIAL (71) We, METAL BOX LIMITED, of Queens House, Forbury Road, Reading RG1 3JH, Berkshire, a British Company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to apparatus for opening flattened tubes of flexible sheet material to enable one or more articles or members to be inserted therein. Although particularly described in relation to the packaging or labelling of articles in stretchable plastics film, the invention is not to be considered as limited to this application.

According to the invention there is provided apparatus for opening a flattened tube of flexible sheet material having transverse lines of weakening along its length and caused to pass through the apparatus along a generally vertical and downward path, the apparatus comprising a pair of first rollers mounted in horizontal, parallel relation for rotation in opposite directions and in horizontal spaced opposition, and a tube opening assembly comprising a body and a pair of opposed further rollers rotatably mounted on the body at one end of the same, the tube opening assembly being adapted and arranged for free vertical suspension within a said tube by cooperation of the further rollers with the peripheries of respective ones of the first rollers through the medium of said tube material at the top end of the body, the body then extending downwardly between the first rollers to a portion of substantial transverse depth by which the tube, having passed between the first and further rollers, is opened, the apparatus further comprising third and fourth pairs of rollers arranged on either side of the said body so as to contact the tube between the first rollers and the said portion of substantial transverse depth, the third and fourth rollers being drivable to advance the tube through the apparatus, the fourth rollers being located to engage the tube below the third rollers and drivable at a greater peripheral speed than the third rollers so as progressively to effect separation of the tube at the lines of weakening.

In order that the invention may be more fully understood an embodiment thereof will now be described, by way of example, and with reference to the accompanying drawings, in which: Fig. 1 shows, in side elevation, an apparatus embodying the invention; Fig. 2 is a perspective view of a tube opening assembly forming part of the apparatus; Fig. 3 shows the assembly of Fig. 2, in side elevation corresponding to Fig. 1 but to a larger scale; Fig. 4 shows the top end of the assembly in side elevation as seen in the direction of the arrow A in Fig. 3; and Fig. 5 is a side elevation corresponding to Fig. 4 showing the assembly together with separating rollers for separating the tube into individual sleeves.

Referring now to the drawings, there is shown a machine arranged for placing openended sleeves 27 of a stretchable plastics sheet material onto containers of which one is shown at 50 in Fig. 1. The sleeves are printed; they serve for labelling the contrainers, which are typically blown-moulded plastics bottles.

The sleeves 27 are successively torn from a web 12 drawn from a reel 51 on a mandrel 53. The web 12 is conventionally formed as a layflat (i.e. flattened) tube by heat-sealing together the two side edges of a strip of the plastics material. Transverse perforation lines 100 (Fig. 5) are formed at regular intervals along the web to defiine the sleeves and form lines along which the sleeves can be torn from one another as will later be described.

From the reel 51 the web is guided by idler rollers 55, 56 so as thereafter to pass through the machine on a generally vertically downward path.

The first operation performed on the web as it leaves the roller 56 is the interposition of vertical bars between the two plies 112, 212 of which it is formed. This is effected by the sleeve opening assembly shown in detail in Figs. 2 to 5.

The vertical bars, of which the inner three are denoted 57 and the outer two are denoted 60 are rigidly attached at their top ends to a horizontal member 13. Struts 59 extend between them to maintain them at their desired horizontal spacing.

The member 13 is mounted at its ends by screws 16 through vertical plates 58.

Support for the plates 58, and thereby the member 13 and bars 57, 60, is provided by two rollers 18 which are rotatably mounted on the plates 58 by conical ended grub screws 17. The rollers extend in parallel relation to one another and to the member 13; they are disposed side-by-side in horizontal alignment below, and symmetrically one to either side of, that member.

Their spacing is sufficient to ensure that at all times they are free from contact with the bars 57, 60 which pass between them.

As can clearly be seen in Fig. 3, the rollers 18 are arranged for rolling engagement with respective ones of two further rollers 8. These rollers are rotatably carried at their ends from the machine frame 42 (Fig. 5) so as to support the sleeve opening assembly. Again, the rollers 8 are horizontally spaced to clear the bars 57, 60 between them.

A pair of rubber rollers 10 are carried from the machine frame vertically beneath the rollers 8, in parallel relation to the same.

The rollers 10 have grooves 61 formed around their periphery in lateral correspondence with the bars 57, 60 so as by accommodating the bars to allow the peripheries of the rollers 10 between the grooves to cooperate resiliently with one another as will later be described.

A further pair of rubber rollers 11 are mounted below the rollers 10 and likewise provided with peripheral grooves 61 to receive the bars 57, 60. The two pairs of rollers 10, 11 are spaced by a vertical distance which is greater than the length of one sleeve in the machine direction but less than the length of two sleeves. The rollers 10 are coupled to an electric motor 70 by a chain or belt drive 71. A further drive 72 between the two pairs of rollers 10, 11 is arranged to drive the rollers 11 at a faster rotational, and hence peripheral, speed than the rollers 10.

To thread the web 12 initially over the sleeve opening assembly the-latter is lifted a short distance to free the rollers 18 from the rollers 8, and the free end of the web is opened and manually passed down over the member 13 and the rollers 18. Subsequently the free edges of the web along its longer sides is fed past the rollers 8 on their inner sides, the sleeve opening assembly is released, and continued manipulation of the web free edge feeds the web in succession between the rollers 10, 11, and lastly over the lower free edges of the bars 57, 60. To allow the web to be passed between them in this way provision is made for the rollers 10, 11 to be inched slowly forward, manually or otherwise.

As it later to be described in greater detail, the sleeve opening assembly is arranged to separate sleeves successively from the reel 51 and feed them downwardly in an opened-out condition to a sleeve applicator located beneath it. This sleeve applicator forms no part of the present invention and is therefore not described in detail; basically, however, it comprises an inclined lifting ram 74 with a lifting platform 75 and arranged to lift a blowmoulded plastics container 50 when guided by å guide plate 76.

Two opposed stretcher plates 77, 78 are arranged between this lifting assembly and the bottom free ends of the bars 57, 60. Of the two end plates the plate 77 is fixed in position; the plate 78, however, is attached to the piston of a ram 79 mounted on the machine frame 42 so that its stroke is orthogonal to that of the ram 74.

Various other items so far not described will become apparent from the following description of operation to label a container 50 on the platform 75, it being initially assumed that the ram 74 is retracted, the ram 79 is extended so that the stretcher plates 77, 78 are in their closely adjacent position shown in Fig. 1, and the web 12 has been fed between the rollers 10, 11 as previously described.

The faster peripheral speed of the rollers 11 in relation to the rollers 10 creates a tension in the web between them so as to separate a sleeve 27 from the end of the web, and feed the sleeve downwardly over the ends of bars 57, 60. Guide plates 22 (Figs. 1 and 5) mounted on either side of the web between the roller pairs 10, 11 prevent any substantial ballooning of the web caused by static electricity, and so ensure that the web is fed properly into the nip between the rollers 11.

The ends of the bars 57 have a substantial depth by virtue of triangular loops 179 formed at their ends, so that the sleeve in passing over them is opened out into tubular form. In this form the sleeve falls down into encircling relation with the free top ends of the stretcher plates 77, 78. When the sleeve is halted the apparatus is as depicted in Fig. 1.

In order to guide the sleeve into its desired position, guide plates 81, 82 fast with the stretcher plates 77, 78 respectively are provided. In addition, eyes 19 are provided on the underside of the bars 57, and lengths of wire 20 are hooked into these eyes so as to hang freely below the bars 57. The wires 20 form restraint members delaying the movement of the top edge of the sleeve to the right as shown in Fig. 1, and by so doing ensure that the sleeve remains in a nearly vertical position until the stretcher plate 78 opens out the sleeve. This is important if the sleeves in their layflat condition are substantially wider than the stretcher plates.

After the sleeve has been located on the stretcher plates in this way a microswitch, photocell or the like actuates the ram 79 to move the stretcher plate 78 away from the stretcher plate 77. This movement circumferentially stretches the engaging part of the sleeve by an amount not exceeding the elastic limit of the sleeve material with the result that the lower end of the sleeve is opened out sufficiently for the container 50 to then be lifted by the ram 74 so as to pass freely into the sleeve between the stretcher plates.

The stretcher plates are of a length to stretch only the lower 60% or so of the sleeve so that a neck 15 formed in the sleeve beyond the free ends of the stretcher plates. Therefore, after the container has been inserted between the stretcher plates, continued extension of the ram 74 causes the container to engage this neck and thereafter elastically stretch the free upper portion of the sleeve as it goes.

Clamping rams 26 having clamping pads 25 on their piston rods are extended after the ram 79 has been retracted, but before the ram 74 has begun its operation. By clamping the lower end of the sleeve against the stretcher plates the rams 26 prevent the ram 74 from pulling the sleeve off the stretcher plates until the ram has, by further extension, pushed the container until the sleeve is in its desired position in relation to the sleeve, as indicated by the broken lines in Fig. 1. The rams 26 are then retracted so that further movement of the ram 74 strips the sleeve off the stretcher plates and so frees the now-labelled container.

The previously mentioned inclination of the ram 74 is provided to enable the container to clear the bottom end of the bars 57, 60 and to provide easy access for dispatch.

In the labelled container the sleeve has a substantial residual tension. This may well be sufficient to prevent any subsequent displacement of the sleeve on the container, particularly if the sleeve material has a relatively high coefficient of friction. However, if desired the sleeve may be positively attached to the container, as by welding.

The invention is not to be considered as limited to the opening of layflat tubes of stretchable plastics material for packaging or labelling, as particularly described. It may have wide application where there is a requirement to open an elongate flattened tube of flexible sheet material which is intermittently or continuously advanced.

WHAT WE CLAIM IS:- 1. Apparatus for opening a flattened tube of flexible sheet material having transverse lines of weakening along its length and caused to pass through the apparatus along a generally vertical and downward path, the apparatus comprising a pair of first rollers mounted in horizontal, parallel relation for rotation in opposite directions and in horizontal spaced opposition, and a tube opening assembly comprising a body and a pair of opposed further rollers rotatably mounted on the body at one end of the same, the tube opening assembly being adapted and arranged for free vertical suspension within a said tube by cooperation of the further rollers with the peripheries of respective ones of the first rollers through the medium of said tube material at the top end of the body, the body then extending downwardly between the first rollers to a portion of substantial transverse depth by which the tube, having passed between first and further rollers, is opened, the apparatus further comprising third and fourth pairs of rollers arranged on either side of the said body so as to contact the tube between the first rollers and the said portion of substantial tranverse depth, the third and fourth rollers being drivable to advance the tube through the apparatus, the fourth rollers being located to engage the tube below the third rollers and drivable at a greater peripheral speed than the third rollers so as progressively to effect separation of the tube at the lines of weakening.

2. Apparatus according to Claim 1 adapted for a said flattened tube of plastics material, which includes guide plates mounted between the third and fourth roller pairs and arranged for preventing substantial ballooning of the tube by static electricity.

3. Apparatus according to Claim 1 or Claim 2, wherein the body comprises a pair of horizontally spaced mounting plates having the further rollers rotatably mounted thereon and extending therebetween, a member extending between the plates in centrally disposed and parallel, elevated relation to the further rollers, and a plurality of vertical bars suspended in parallel spaced relation from the said member at their top ends, the third and fourth rollers having

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (4)

**WARNING** start of CLMS field may overlap end of DESC **. In order to guide the sleeve into its desired position, guide plates 81, 82 fast with the stretcher plates 77, 78 respectively are provided. In addition, eyes 19 are provided on the underside of the bars 57, and lengths of wire 20 are hooked into these eyes so as to hang freely below the bars 57. The wires 20 form restraint members delaying the movement of the top edge of the sleeve to the right as shown in Fig. 1, and by so doing ensure that the sleeve remains in a nearly vertical position until the stretcher plate 78 opens out the sleeve. This is important if the sleeves in their layflat condition are substantially wider than the stretcher plates. After the sleeve has been located on the stretcher plates in this way a microswitch, photocell or the like actuates the ram 79 to move the stretcher plate 78 away from the stretcher plate 77. This movement circumferentially stretches the engaging part of the sleeve by an amount not exceeding the elastic limit of the sleeve material with the result that the lower end of the sleeve is opened out sufficiently for the container 50 to then be lifted by the ram 74 so as to pass freely into the sleeve between the stretcher plates. The stretcher plates are of a length to stretch only the lower 60% or so of the sleeve so that a neck 15 formed in the sleeve beyond the free ends of the stretcher plates. Therefore, after the container has been inserted between the stretcher plates, continued extension of the ram 74 causes the container to engage this neck and thereafter elastically stretch the free upper portion of the sleeve as it goes. Clamping rams 26 having clamping pads 25 on their piston rods are extended after the ram 79 has been retracted, but before the ram 74 has begun its operation. By clamping the lower end of the sleeve against the stretcher plates the rams 26 prevent the ram 74 from pulling the sleeve off the stretcher plates until the ram has, by further extension, pushed the container until the sleeve is in its desired position in relation to the sleeve, as indicated by the broken lines in Fig. 1. The rams 26 are then retracted so that further movement of the ram 74 strips the sleeve off the stretcher plates and so frees the now-labelled container. The previously mentioned inclination of the ram 74 is provided to enable the container to clear the bottom end of the bars 57, 60 and to provide easy access for dispatch. In the labelled container the sleeve has a substantial residual tension. This may well be sufficient to prevent any subsequent displacement of the sleeve on the container, particularly if the sleeve material has a relatively high coefficient of friction. However, if desired the sleeve may be positively attached to the container, as by welding. The invention is not to be considered as limited to the opening of layflat tubes of stretchable plastics material for packaging or labelling, as particularly described. It may have wide application where there is a requirement to open an elongate flattened tube of flexible sheet material which is intermittently or continuously advanced. WHAT WE CLAIM IS:-

1. Apparatus for opening a flattened tube of flexible sheet material having transverse lines of weakening along its length and caused to pass through the apparatus along a generally vertical and downward path, the apparatus comprising a pair of first rollers mounted in horizontal, parallel relation for rotation in opposite directions and in horizontal spaced opposition, and a tube opening assembly comprising a body and a pair of opposed further rollers rotatably mounted on the body at one end of the same, the tube opening assembly being adapted and arranged for free vertical suspension within a said tube by cooperation of the further rollers with the peripheries of respective ones of the first rollers through the medium of said tube material at the top end of the body, the body then extending downwardly between the first rollers to a portion of substantial transverse depth by which the tube, having passed between first and further rollers, is opened, the apparatus further comprising third and fourth pairs of rollers arranged on either side of the said body so as to contact the tube between the first rollers and the said portion of substantial tranverse depth, the third and fourth rollers being drivable to advance the tube through the apparatus, the fourth rollers being located to engage the tube below the third rollers and drivable at a greater peripheral speed than the third rollers so as progressively to effect separation of the tube at the lines of weakening.

2. Apparatus according to Claim 1 adapted for a said flattened tube of plastics material, which includes guide plates mounted between the third and fourth roller pairs and arranged for preventing substantial ballooning of the tube by static electricity.

3. Apparatus according to Claim 1 or Claim 2, wherein the body comprises a pair of horizontally spaced mounting plates having the further rollers rotatably mounted thereon and extending therebetween, a member extending between the plates in centrally disposed and parallel, elevated relation to the further rollers, and a plurality of vertical bars suspended in parallel spaced relation from the said member at their top ends, the third and fourth rollers having

grooves to accommodate the bars extending therebetween, and the said portion of substantial transverse depth comprising loops formed in said bars at the bottom ends thereof.

4. Apparatus for opening a flattened tube of flexible sheet material, substantially as hereinbefore described with reference to the accompanying drawings.