Abstract:
The invention relates to a device for forming sleeve-like foil envelopes from a flat strip of foil material ( 12 ), at least comprising supply means ( 10 ) for supplying the flat strip of foil material; cutting means ( 20 ) for cutting the strip of foil material through over the entire width thereof so as to obtain a foil envelope strip of a specific length having a first and a second free edge ( 120   a   , 120   b ); at least one enveloping unit, around which the foil envelope strip is to be wrapped; joining means disposed near said enveloping unit for joining said first and said second free edge together, so as to obtain a sleeve-like foil envelope; as well as discharge means for discharging the sleeve-like foil envelope thus formed from the enveloping unit.

Description:
This patent application is a U.S. National Phase of International Patent Application No. PCT/NL09/00109, filed May 1, 2009, which claims priority from Netherlands Patent Application No. 1035494, filed May 29, 2008, the disclosures of which are incorporated herein by reference in their entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a device for forming sleeve-like foil envelopes from a flat strip of foil material, at least comprising supply means for supplying the flat strip of foil material; cutting means for cutting the strip of foil material through over the entire width thereof so as to obtain a foil envelope strip of a specific length having a first and a second free edge; at least one enveloping unit, around which the foil envelope strip is to be wrapped; joining means disposed near said enveloping unit for joining said first and said second free edge together, using heat, so as to obtain a sleeve-like foil envelope; as well as discharge means for discharging the sleeve-like foil envelope thus formed from the enveloping unit. 
     Such a device is quite common, it is used for forming sleeve-like foil envelopes, which, after being formed, can be placed from the enveloping unit over an object with some oversize. The foil material is made of a so-called shrink material, which shrinks as a result of heat being applied and which forms with a close fit to the shape of the bottle or container around which the sleeve-like envelope has been arranged. 
     To obtain a sleeve-like foil envelope, a strip of foil material is supplied from a stock thereof to a cutting unit, where the strip of foil material is cut to the desired length. The individual foil envelope strips thus obtained are each separately wrapped around an enveloping unit, whereupon the two edges are joined together by joining means (also called sealing means), using heat, so as to form a cover. 
     The sleeve-like foil envelope thus realised is subsequently removed from the enveloping unit and placed over a bottle or container with a certain (slight) oversize. The foil material is made of a so-called shrink material, and when the bottle or container with the surrounding foil envelope is passed through a heating channel, the oversize sleeve-like foil envelope will shrink and close around the bottle or container with a close fit. 
     2. Description of the Related Art 
     A drawback of the known devices is that they are only suitable for processing thick or stiff foil materials if a high processing rate is to be realised. When thinner or more flexible foil materials are used, the processing rate must be reduced in order to prevent undesirable jamming of the device. The device will become clogged and jam in such situations, which is undesirable. 
     SUMMARY OF THE INVENTION 
     The object of the invention is to provide a device as referred to in the introduction, which makes it possible to process thin, flexible foil materials as well, without the device becoming clogged and/or jamming. According to the invention, the supply means to that end have a curved surface, over which the flat strip of foil material is to be passed. 
     The strip of foil material is thus given a curved cross-section while being transported to the cutting means and the enveloping unit, resulting in additional stiffness, thereby preventing jamming of the device due to clogging of the thin foil material. 
     In a functional embodiment, the cutting means are movable in the curved plane of the supply means. This makes it possible to form individual foil envelope strips simultaneously while supplying the strip of foil material, resulting in a significantly increased speed and capacity of the enveloping device according to the invention. 
     More specifically, the cutting means comprise at least one cutting element. 
     According to the invention, in order to realise a straight cutting line in the foil material being moved over the curved surface, the at least one cutting element makes an angle with the longitudinal direction of the supply means. 
     In one embodiment according to the invention, the cutting element is more functionally configured as a rotary, disc-shaped cutting element. 
     According to a specific embodiment, in order to cut the foil material in an effective manner, the cutting element mates with a cutting roller to be placed in abutment with the cutting element. 
     An effective construction requiring little installation space can be realised in that according to the invention the supply means are cylindrical in shape. 
     An additional gain as regards installation space is realised in that according to the invention the cutting means are disposed within the cylindrical supply means. 
     According to a specific aspect of the device according to the invention, the cutting means comprise a rotatable cylindrical ring, which cylindrical ring is concentrically disposed relative to the cylindrical supply means. Thus, the foil strip being supplied can be cut to the desired length in one operation by the cutting means so as to obtain individual foil envelope strips. 
     To realise an effective transportation of the foil envelope strip in the direction of the cutting means, the supply means may comprise at least one drivable conveying roller to be supported on said curved surface, between which the flat strip of foil material can be passed. 
     To realise an effective transportation of the foil envelope strip in the direction of the enveloping unit, the supply means may comprise at least one drivable further conveying roller at the location of the cutting means for carrying the individual foil envelope strip to said at least one enveloping unit. 
     According to another special embodiment of the device, in order to further prevent or avoid jamming and standstill of the device, the supply means may comprise guide means at the location of said cutting means for guiding the individual foil envelope strip to said at least one enveloping unit. 
     In a specific embodiment, said guide means comprise two parallel, spaced-apart guide plates. Between said guide plates, the foil envelope strip can be passed (retained) so as to realise a smooth transfer, without any jamming, to the enveloping unit. 
     More functionally, in order to realise an improved guidance of the foil envelope strip, the guide means may comprise at least one spray nozzle for a medium under pressure, which spray nozzle is directed in the conveying direction of the foil envelope strip. 
     In another specific embodiment, said at least one spray nozzle is provided in at least one of said guide plates. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will now be explained in more detail with reference to a drawing, in which: 
         FIG. 1  shows an embodiment of a device according to the invention; 
         FIGS. 2   a - 2   b - 3 - 4  show various embodiments of a device according to the invention. 
     
    
    
     For a better understanding of the invention, like parts will be indicated by identical numerals in the description of the figures below. 
       FIG. 1  and  FIG. 2   a  show in top plan view and in side view, respectively, an embodiment of the device according to the invention indicated at  1 . 
     DETAILED DESCRIPTION OF THE INVENTION 
     The device for forming sleeve-like foil envelopes  12   −2 - 12   −1 - 12   0 - 12   +1 -etc from a flat strip of foil material  12  is made up of a carousel of several enveloping units  30   a - 30   b - 30   c -etc- 30   l , which is rotatable about an axis  40 , around each of which enveloping units  30   a - 30   b - 30   c -etc- 30   l  a free foil envelope strip  12   −2 - 12   −1 - 12   0 - 12   +1 -etc obtained from the strip of foil material  12  is to be arranged. 
     Each individual foil envelope strip has a specific length, depending on the product to be enveloped (a bottle or a container) and is provided with a first and a second free edge  120   a ,  120   b , respectively. Each enveloping unit  30   a - 30   b - 30   c -etc- 30   l  around which the foil envelope strip is to be placed is made up of a body  30   a - 30   b - 30   c -etc- 30   l , which is rotatably driven about an axis  31 . The rotation about the axis  31  of each enveloping unit  30   a - 30   b - 30   c -etc- 30   l  takes place by drive means (not shown), which are assumed to be generally known. 
     To supply an individually obtained foil envelope strip  12   0 -etc to each enveloping unit  30   a -etc, supply means  10  are provided for carrying the flat strip of foil material  12  towards cutting means  20 . 
     According to the invention, the supply means  10  have a curved surface  11   a , as shown in  FIG. 1 , over which the flat strip of foil material can be passed. As a result of the curved surface  11   a , over which the flat strip of foil material  12  is passed, the strip of foil material  12  is given a curved cross-section upon being transported in the direction of the cutting means  20  and the respective enveloping unit  30   a - 30   b - 30   c -etc, resulting in additional internal stiffness. Thus, undesirable jamming of the device, for example due to clogging of the thin foil material  12 , is prevented. 
     In this way it is possible not only to process thinner flexible foil materials, but also to operate the device at a higher speed. 
     As is clearly shown in  FIGS. 1 ,  3  and  4 , the cutting means  20  are according to the invention movable in the curved plane  11   a  of the supply means  10 . 
     The supply means  10  are configured as a cylindrical tube having a longitudinal axis  10 ′, which is oriented at a specific angle relative to the longitudinal axis of each enveloping unit  30   a - 30   b - 30   c -etc and the axis of rotation  40  of the enveloping carrousel. More in particular, and as shown in  FIGS. 3 and 4 , the cutting means  20  are disposed within the cylindrical tube of the supply means  10  and made up of a cylindrical ring  21 , which is arranged concentrically with the cylindrical tube  10 . 
     According to the invention, the cutting means  20  comprise at least one cutting element  22 , more in particular two cutting elements  22 ′- 22 ″, as is clearly shown in  FIG. 4 . The cutting element  22  (or the cutting elements  22 ′- 22 ″) are arranged in such a manner within the cutting means  20  that the cutting blades extend just outside the circumferential surface of the cylindrical ring  21 . 
     Since the rotatable cylindrical cutting ring  21  is arranged concentrically with the cylindrical supply means  10 , the supply means  10  are composed of two cylindrical tube elements  11   a - 11   b . The cylindrical tube element  11   a  functions as a cylindrical supply tube, whilst the cylindrical tube element  11   b  functions as a cylindrical discharge tube for discharging individually realised foil envelope strips in the direction of the respective enveloping unit. 
     During operation, supply means  13   a - 13   b  move the flat strip of foil material  12  over the curved surface of the cylindrical tube  10  in the direction of the cutting means  20 . 
     Supply means for supplying the flat strip of foil material  12  are made up of at least one drivable conveying roller  13   a , which, as is clearly shown in  FIG. 5 , can be rotatably driven by a driving motor  13   a ′ as known per se. Likewise, the supply means comprise at least one drivable further conveying roller  13   b  for supplying the individually obtained foil envelope strip  12   −2 - 12   −1 - 12   0 - 12   +1 -etc. Said further conveying roller  13   b  can also be rotatably driven in a suitable manner by a driving motor  13 ′. 
     The supply means  13   a - 13   b  are configured as a drivable conveying roller to be supported on the curved surface  11   a , which thus carries along the flat strip of foil material  12  over the curved surface  11   a  in the direction of the cutting means  20 . 
     More in particular, the drivable conveying roller  13   a  functions to carry the flat strip of foil material  12  over the curved surface  11   a  in the direction of the cutting means  20 . The further driving roller  13   b  functions to carry the individual envelope strip  12   0 - 12   −1 - 12   −2 -etc realised by the cutting means  20  to the respective enveloping unit  30   a - 30   b - 30   c -etc-. 
     As already said before, the cutting means  20  are made up of a rotatable cylindrical ring  21  and one or more cutting elements  22  ( 22 ′- 22 ″) of the cutting blade, which extends just outside the circumferential surface of the cylindrical ring  21  (see  FIG. 4 ). As is clearly shown in  FIG. 1 , the flat strip of foil material  12  is passed over the curved surface  11   a  of the cylindrical supply tube  10 , being oriented at an angle thereto. To obtain individual foil envelope strips  12   0 -etc, the cutting elements  22  ( 22 ′- 22 ″) must thus also be disposed at an angle α to the longitudinal direction  10 ′ of the cylindrical supply tube. Said angle α is clearly shown in  FIG. 1 . 
     To obtain individual foil envelope strips  12   0 -etc, the cutting element  22  must be moved in the curved plane  11   a  of the cylindrical supply tube  10  at such a speed that a straight (right-angled) cutting edge is realised in the flat strip of foil material  12 . 
     This requires a precise adjustment of the supply rate of the flat strip of foil material  12  over the curved surface  11   a  (realised by the driving roller  13   a  of the supply means) and the rotational speed of the cutting blade  22  in the curved plane  11   a.    
     The cutting element  22  ( 22 ′- 22 ″) is to that end (see  FIG. 4 ) rotatably mounted in a (likewise rotatable) cylindrical ring  21 , which ring  21  is disposed concentrically with the cylindrical supply tube  10  (see  FIG. 3 ). The cylindrical ring is thus rotatable about its axis  21   a , which is concentrical with and coincides with the longitudinal axis  10 ′ of the cylindrical supply tube  10 . The cutting elements  22 ′- 22 ″, which are movable in the circumferential playing of the curved surface  11   a , are likewise rotatable about their axis  22   a ′- 22   a ″. Two endless driving belts  25 ′- 25 ″ are to that end passed over the shafts  21   a - 22   a ′- 22   a ″, which driving belts impart a rotation about the shafts  22   a ′- 22   a ″ synchronised with the rotational speed of the cylindrical ring  21  (about the shaft  21   a ). 
     Because of the rotation of the cylindrical ring  21 , the cutting elements  22 ′- 22 ″ will come into contact with the flat strip of foil material  12  being supplied over the curved surface  11   a  of the cylindrical supply tube with every revolution. In order to be able to adequately cut said flat strip of foil material  12 , each cutting element  22 ′- 22 ″ coacts with a cutting roller  23 ′- 23 ″ to be placed into abutment with the cutting element  22 ′- 22 ″. Said cutting rollers  23 ′- 23 ″ are connected to the rotatable cylindrical ring  21  by means of a connecting yoke  24 ′- 24 ″. The two cutting rollers  23 ′- 23 ″ thus rotate jointly with the corresponding cutting elements  22 ′- 22 ″ and will form two separate right-angled cutting edges  12 ′ in the flat strip of foil material with every full revolution of the cylindrical ring  21 . 
     Since the first driving roller  13   a  supplies the flat strip of foil material at a constant speed over the curved surface  11   a  of the cylindrical supply tube  10  in the direction of the cutting means  20 , each cutting element  22 ′- 22 ″ will form a cutting edge  12 ′ in the foil material  12  with every full revolution of the cylindrical cutting ring  21 . 
     Thus, individual foil envelope strips  12   0 - 12   +1 - 12   +2 -etc are obtained, which strips are carried towards an enveloping unit  30   a - 30   b - 30   c -etc by means of said further conveying roller  13   b.    
     By gearing the speed at which the strip of foil material  12  is supplied (by the conveying roller  13   a ), the rotational speed of the cylindrical cutting ring  21  and the angle relative to the longitudinal axis  10 ′ at which the flat strip of foil material  12  is supplied over the curved surface  11   a  to each other, it becomes possible to control the length of each individually obtained foil envelope strip  12   0 -etc. 
     The curved shape of the circumferential surface  11   a  of the cylindrical supply tube  10  sets up a certain pre-tension in the flat strip of foil material  12 . The amount of pre-stress in the individually obtained foil envelope strips  12   0 -etc is smaller, however, so that there is still a risk of the device becoming clogged and jamming at the location of the enveloping unit  13   a -etc, especially when very thin and flexible foil materials are used. 
     In order to prevent an individual foil envelope strip  12   0  from clogging upon being moved in the direction of the enveloping unit  30   a  by the further conveying roller, another embodiment of the invention is provided with guide means  50 . Said guide means  50  provide a smooth guidance of the individual foil envelope strips  12   0 - 12   +1 - 12   +2 -etc to the respective enveloping unit  30   a -etc. 
     As shown in  FIG. 2   b , the guide means  50  comprise two parallel, spaced-apart guide blades  50   a - 50   b , between which the individually obtained foil envelope strips  12   0 -etc can be guided towards the enveloping unit. 
     In order to further support the movement of each individual foil envelope strip  12   0 -etc towards the enveloping unit (this in order to prevent the device from jamming due to possible clogging of the thin flexible foil material), the guide means  50  may also comprise at least one spray nozzle  52 , by means of which the medium under pressure can be directed in the conveying direction of the foil envelope strips  12   0 -etc. This, too, helps to realise a more controllable and controlled movement of each individual foil envelope strip  12   0 -etc in the direction of the respective enveloping unit. 
     More in particular, the spray nozzle is  52  may be provided in at least one of the guide blades  50   a - 50   b  of the guide means. 
     It will be understood that it is possible to form large numbers of foil envelope strips at a high processing rate from a flat strip of foil material  12  to be supplied when using the device according to the invention. The curved surface  11   a  creates a certain pre-stress in the curved foil material  12 , whilst the cutting means  20 , which are movable in the curved plane of the supply means  10 , make it possible to form several individual foil envelope strips having a precisely adjustable length in a quick and constant manner. 
     Although this is not shown in the drawings and not relevant to the invention, each enveloping unit  30   a - 30   b - 30   c -etc is provided with joining means for joining together the free edges  120   a - 120   b  of each foil envelope strip wrapped around the respective enveloping unit, for example by means of heat. By fusing the two free edges of each foil envelope strip together by means of heat, a cover-like foil envelope is realise, which can subsequently be discharged from each enveloping unit by discharge means (likewise not shown) and be placed over a container or bottle.