Abstract:
A method of inserting elongate elements positioned in end-to-end relationship into a continuous resilient flexible sleeve is disclosed. The sleeve has a wall that extends around and partially encloses the elongate elements to hold them in position within the sleeve and the wall has a longitudinally extending opening configured to enable a user to make contact with elongate elements held by said sleeve, through the opening, to push them along the sleeve towards, and out of one end of the sleeve. The insertion method includes continuously feeding the sleeve through a member that deforms a region of the sleeve to enlarge the opening and simultaneously feeding a continuous length of elongate elements positioned in end-to-end relationship into the sleeve through the enlarged opening in said region so that the sleeve closes around the elongate elements when it travels beyond said member.

Description:
TECHNICAL FIELD 
       [0001]    The invention relates to a method and an apparatus for inserting elongate elements into a sleeve in a continuous manufacturing process. The elongate elements are particularly but not exclusively rod shaped elements, such as filter units for smoking articles. 
       BACKGROUND 
       [0002]    The Applicant&#39;s co-pending GB patent application GB1209261.5 discloses a sleeve for holding a plurality of elongate elements, such as filter units for smoking articles, in end-to-end relationship. The sleeve at least partially encloses the filter units and the filter units may have a diameter which is at least slightly greater than the diameter of the sleeve when no filter elements are received therein, so that when filter elements are received in the sleeve, the sleeve is deformed by the filter elements against a bias provided by the resilience of the material from which the sleeve is made. Thus, the filter elements are held in position within the sleeve and do not fall out of the sleeve without the application of pressure being applied thereto. An opening extends along the length of the sleeve to allow a user to contact a filter element held therein so that pressure may be applied to the filter element that is sufficient to overcome the bias provided by the resilience of the material and push the filter units out of the open end of the sleeve using a finger. 
       SUMMARY 
       [0003]    In accordance with embodiments of the invention, there is provided an insertion method that comprises: continuously feeding the sleeve over a member that deforms a region of the sleeve to enlarge the opening and, simultaneously feeding a continuous length of elongate elements positioned in end-to-end relationship into the sleeve through the enlarged opening in said region so that the sleeve closes around the elongate elements when it travels beyond said member. 
         [0004]    Said member that deforms a region of the sleeve to enlarge the opening may comprise an arcuately-shaped or cylindrical former and the method includes passing the sleeve around a portion of said former so that it follows an arcuate path to thereby cause the opening in the sleeve to widen. 
         [0005]    The method may include passing the sleeve around the former with its opening facing radially away from the longitudinal axis of the former so that the opening in the sleeve is widened. 
         [0006]    The method may further include the step of maintaining the deformation in a region of the sleeve beyond a point at which it stops following an arcuate path around the former. 
         [0007]    The step of maintaining deformation in a region of the sleeve may comprise passing it between a support plate and a sleeve retaining plate to prevent release of the deformation and return of the region of the sleeve to its original non-deformed configuration. 
         [0008]    The method may include the step of feeding the sleeve and the elongate elements contained within the sleeve through a garniture, positioned downstream of said mechanism, to close the sleeve around the elongate elements. 
         [0009]    The method may include the step of releasing the sleeve so that it closes around the elongate elements contained within the sleeve due to its own resilience downstream of said member. 
         [0010]    The method may comprise the step of applying heat to the sleeve to soften it prior to deformation and/or to facilitate closing of the sleeve around the elongate elements. 
         [0011]    The step of feeding of elongate elements may include arranging a continuous length of elongate elements in end-to-end relation so that there are no spaces between said elements, and pushing said continuous length into the opened sleeve. 
         [0012]    In accordance with embodiments of the invention, there is also provided a method of manufacturing a continuous resilient flexible sleeve to hold a plurality of elongate elements positioned in end-to-end relationship, the continuous resilient flexible sleeve comprising a wall that extends around and partially encloses said elongate elements to hold them in position within the sleeve, the wall having a longitudinally extending opening configured to enable a user to make contact with elongate elements held by said sleeve through said opening to push them along the sleeve towards, and out of, one end of the sleeve, the method comprising the step of drawing a web of material through a moulding die configured to deform said web into the sleeve. 
         [0013]    The method may further comprise the step of heating said moulding die. 
         [0014]    The method may further comprise the step of cooling the moulded continuous sleeve prior to inserting elongate elements into said sleeve. 
         [0015]    In accordance with embodiments of the invention, there is also provided an apparatus for inserting elongate elements positioned in end-to-end relationship into a continuous resilient flexible sleeve comprising a wall that extends around and partially encloses said elongate elements to hold them in position within the sleeve, the wall having a longitudinally extending opening configured to enable a user to make contact with elongate elements held by said sleeve through said opening to push them along the sleeve towards, and out of, one end of the sleeve, the insertion apparatus comprising: a member configured to deform a region of the sleeve to enlarge the opening as said sleeve passes through said apparatus, and a conveyor to simultaneously feed a continuous length of elongate elements positioned in end-to-end relation into the sleeve through the enlarged opening in said region so that the sleeve closes around the elongate elements when it travels beyond said apparatus. 
         [0016]    The member that deforms a region of the sleeve to enlarge the opening may comprise a cylindrical former around at least a portion of which said sleeve is passed so that it follows an arcuate path to thereby cause the opening in the sleeve to widen. 
         [0017]    The cylindrical former may be disposed such that the sleeve passes around the former with its opening facing radially away from the longitudinal axis of the former so that the opening in the sleeve is widened. 
         [0018]    The apparatus may further comprise a support plate and a retaining plate positioned such that the sleeve passes between the support plate and the retaining plate as the sleeve leaves said member to maintain the deformation of the sleeve and prevent the region of the sleeve returning to its original non-deformed configuration. 
         [0019]    The apparatus may further comprise a garniture positioned downstream of said apparatus, through which the sleeve and the elongate elements contained within the sleeve are fed to close the sleeve around the elongate elements. 
         [0020]    The support plate and retaining plate may be configured to release the deformed region of the sleeve so that is closes around the elongate elements contained within the sleeve due to its own resilience. 
         [0021]    The apparatus may further comprise a heater disposed to heat the sleeve to soften it prior to deformation and/or to facilitate closing of the sleeve around the elongate elements. 
         [0022]    In accordance with embodiments of the invention, there is also provided an apparatus for manufacturing a continuous resilient flexible sleeve to hold a plurality of elongate elements positioned in end-to-end relationship, the continuous resilient flexible sleeve comprising a wall that extends around and partially encloses said elongate elements to hold them in position within the sleeve, the wall having a longitudinally extending opening configured to enable a user to make contact with elongate elements held by said sleeve through said opening to push them along the sleeve towards, and out of, one end of the sleeve, the apparatus comprising a moulding die through which a web of material is drawn to deform said web of material to form the sleeve. 
         [0023]    The moulding die may comprise a tubular pathway through which the web of material is drawn to form the sleeve, said tubular pathway also comprising a tapered inlet. 
         [0024]    The moulding die may comprise a first portion having a first recess and a second portion having a second recess, the second portion being moveable relative to the first portion such that when the moulding die is in operation the second portion is in contact with the first portion and the first and second recesses are aligned to create said tubular pathway. 
         [0025]    The moulding die may further comprise an arm extending from the first or second portion to support a moulding pin so that said pin extends at least partially into the tubular pathway. 
         [0026]    The moulding die may comprise a steam inlet for receiving steam and at least one steam outlet for releasing said steam towards the web of material, as it is drawn through the moulding die. 
         [0027]    The at least one steam outlet may be disposed in the first recess or in second recess. 
         [0028]    The moulding pin may comprise at least one steam outlet. 
         [0029]    The apparatus may further comprise a cooling unit disposed downstream of the moulding die to cool the moulded sleeve prior to inserting elongate elements into said sleeve. 
         [0030]    The cooling unit may comprise a funnel shaped chamber, through which the sleeve passes from the narrow end to the larger end, the chamber also comprising an air inlet for receiving compressed air to cool the sleeve. 
         [0031]    The apparatus may further comprise a cutter to cut the web of material prior to that material being drawn through said moulding die to form said sleeve. 
         [0032]    The cutter may be configured to cut an edge profile onto the web of material. 
         [0033]    The elongate elements may be filter units for a smoking article. 
         [0034]    In accordance with another embodiment of the invention, there is provided a resilient flexible sleeve containing elongate elements positioned in end-to-end relationship, the sleeve comprising a wall that extends around and partially encloses said elongate elements to hold them in position within the sleeve when inserted therein, the wall having a longitudinally extending opening configured to enable a user to make contact with elongate elements held by said sleeve through said opening to push them along the sleeve towards, and out of, one end of the sleeve, the sleeve being manufactured according to the method of the invention and and/or the elongate elements being inserted into the sleeve using the method of insertion according to the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0035]    Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: 
           [0036]      FIG. 1  shows a sleeve for a holding a plurality of elongate elements; 
           [0037]      FIG. 2  shows the sleeve of  FIG. 1  with a plurality of elongate elements, such as filter units for a smoking article, being held in the sleeve in end-to-end relationship; 
           [0038]      FIG. 3  shows a process diagram for an embodiment of the method for manufacturing a sleeve holding elongate elements; 
           [0039]      FIG. 4  shows a schematic process diagram of an embodiment of the apparatus for manufacturing a sleeve for elongate elements; 
           [0040]      FIG. 5  shows the preparation cutter assembly of the apparatus of  FIG. 4 ; 
           [0041]      FIGS. 6 a  to 6 c    show the sleeve forming apparatus and cooling assembly of the apparatus of  FIG. 4 ; 
           [0042]      FIGS. 7 a  and 7 b    show the sleeve opening mechanism of the apparatus of  FIG. 4 ; 
           [0043]      FIG. 8  shows the sleeve opening mechanism, collator and combining apparatus of the apparatus of  FIG. 4 ; 
           [0044]      FIGS. 9 a  to 9 d    show different embodiments of the sleeve retaining assembly of the apparatus of  FIG. 4 ; 
           [0045]      FIG. 10  shows an example of a garniture of the apparatus of  FIG. 4 ; and, 
           [0046]      FIG. 11  shows a cutting configuration for separating the continuous sleeve and elongate elements into the individual products of  FIG. 2 . 
       
    
    
     DETAILED DESCRIPTION 
       [0047]      FIGS. 1 and 2  show a sleeve  1  holding a plurality of filter units  9 , as disclosed in the Applicant&#39;s co-pending GB patent application number GB1209261.5, which is hereby fully incorporated by reference.  FIG. 1  shows the sleeve without any elongate elements and  FIG. 2  shows the sleeve  1  holding a plurality of elongate elements  9  in end-to-end relationship. 
         [0048]    As shown in  FIG. 2 , filter units  9  are received within the sleeve  1 , in a central space  3  (see  FIG. 1 ), in end-to-end relationship. A wall  2  extends around and partially encloses the elongate elements  9  to hold them in position within the sleeve  1 . An opening  4  is formed in the wall  2  and allows a user to contact the filter units  9  within the sleeve  1  and remove them by pushing the filter units  9  towards the open ends  10 ,  11  of the sleeve. The wall  2  of the sleeve  1  extends around more than half of the circumference of the filter units  9  so that the filter units are retained within the sleeve  1  and can only be removed by pushing the filter units  9  towards and out of the open ends  10 ,  11 . The sleeve  1  is preferably formed from a resiliently deformable material and the filter units have a diameter which is slightly greater than the diameter of the empty sleeve, so that the sleeve is deformed by the filter elements when the filter elements are received therein. The filter elements are then held snugly within the sleeve due to the resilience of the material from which the sleeve is made. This prevents the filter elements from sliding out of the ends of the sleeve in the absence of any pressure being applied thereto by a user. 
         [0049]    As shown in  FIGS. 1 and 2 , the edges  5 ,  6  of the opening may have a profile, such as a sinusoidal wave with peaks  7  and troughs  8 . The pitch of the wave (distance between two peaks  7 ) may equal the length of a filter unit  9  to be received in the sleeve  1 . Alternatively, the wave may take various forms, such as a saw-tooth profile, square waves or the peaks and troughs of the waves might not be aligned with each other. Alternatively, the edges  5 ,  6  of the sleeve  1  may be straight and parallel to each other or straight and tapered so that the size of the opening  4  is not constant along the length of a sleeve  1 . 
         [0050]    The manufacturing method and apparatus described herein and defined in the claims is for producing embodiments of the sleeve  1  for elongate elements with a continuous opening  4  along the length of the sleeve  1 , as shown in  FIGS. 1 and 2 . 
         [0051]    The sleeve described with reference to  FIGS. 1 and 2  can be made from a polymer material such that the sleeve has sufficient rigidity to prevent the filter units  9  falling out of the sleeve  1  via the opening  4  but resilient enough to allow the filter units  9  to be slid along the sleeve  1  in response to the application of pressure thereto with a finger or thumb. The sleeve  1  may be made from a transparent or translucent material such that a user can see the quantity, colour and position of the filter units  9  within the sleeve  1 . 
         [0052]      FIG. 3  shows a schematic method diagram for the manufacturing system for producing a sleeve  1  holding filter units  9 , as described above with reference to  FIG. 2 . 
         [0053]    The method includes two parallel processes; the first process  13  prepares the filter units and the second process  12  forms and prepares a continuous sleeve. These first and second processes  12 ,  13  both supply a combining unit  14  which inserts the filter units into the continuous sleeve. An optional sleeve re-forming process  15  and a cutting process  16  complete the manufacturing method and the continuous sleeve is cut into the required length sleeve products, as shown in  FIG. 2 . 
         [0054]    The first process  13  receives a combination of single length filter units  17  and double length filter units  18  which are fed onto a conveyor  19  in a pre-determined end-to-end arrangement; double length inserts  18  are arranged on the conveyor  19 , with each being separated by a plurality of single length inserts  17  in a repeating pattern, for reasons which will become apparent later. The filter units  17 ,  18  are then collated  20  so that they are bunched together with no space between the filter units. 
         [0055]    The second process  12  receives material from an input  21 , such as a reel or from a previous process. The material moves along the second process  12  as a web of material being controlled by rollers and other similar web handling apparatus and the material is formed into a continuous sleeve. 
         [0056]    The material may initially pass through an optional preparation process  22  which may cut the material to add an edge profile, or other feature, prior to the sleeve forming process  23 . Alternatively, the preparation process may involve trimming the material to alter the width of the web of material. 
         [0057]    The web of material is drawn through the sleeve forming process  23  which moulds the material into a continuous sleeve with a continuous opening along one side, similar the sleeve shown in  FIG. 1  but formed in a continuous manner. During the sleeve forming process  23  the flat material is wrapped into a substantially tubular form, with a space left between the edges of the material so a continuous opening is formed along one side of the sleeve, between the edges. Therefore, any edge profile added to the material during the material preparation process  22  will create the edge profile of the opening (for example the wave profile on the edges  5 ,  6  of the opening  4 —see  FIGS. 1 and 2 ). 
         [0058]    The sleeve forming process  23  may include a heater or a means for heating the material to assist the moulding of the material into a sleeve and a subsequent cooling process  24  may be included to cool the newly formed continuous sleeve before the sleeve is provided to the combining process  14 . Heating the material will increase the plasticity of the material, allowing it to be more easily formed into the continuous sleeve, and the sleeve may be cooled after the forming process  23  to return the material to an elastic state. Any residual heat that remains in the continuous sleeve after it has been formed may cause the sleeve to be plastically deformed by subsequent processes, disturbing the moulded shape formed by the sleeve forming process  23 . 
         [0059]    The combining process  14  enlarges the continuous opening along the sleeve and inserts the collated filter rods into the sleeve through the continuous opening, as explained in more detail later. 
         [0060]    After the inserts have been inserted into the sleeve, the sleeve is re-formed  15  to the shape defined by the sleeve forming process  23 , but with filter units within the sleeve. The sleeve may return to its non-deformed, moulded shape because of the resilient or elastic properties of the sleeve material. Alternatively, a re-forming mechanism may actively re-form the sleeve. 
         [0061]    A final cutting process  16  separates the continuous sleeve into the individual sleeve products shown in  FIG. 2 . Each sleeve may contain, for example, 8 filter inserts of the same length. To achieve this, the cutting process  16 , which may include a rotary blade or guillotine, cuts the continuous sleeve in a position corresponding to the middle of each double length filter rod unit  18 , thus separating the continuous sleeve into equal size products and cutting the double length filter rod units  18  to the desired single length, which thereby form the end filter units of each sleeve product. 
         [0062]      FIG. 4  shows a schematic diagram of an apparatus for manufacturing the sleeves with elongate elements as shown in  FIG. 2 . The apparatus performs the method described with reference to  FIG. 3 . 
         [0063]    Generally, as previously explained, the manufacturing apparatus includes two parallel processes; a first process  13  which collates filter units and a second process  12  (see  FIG. 3 ) which forms a continuous sleeve. The first and second processes meet so that the filter units are inserted into the continuous sleeve which is then cut to produce the sleeve products  1  (see  FIG. 4 ). 
         [0064]    The first process  13  (see also  FIG. 3 ) comprises a conveyor  19  which delivers single and double length filter units  17 ,  18  that have been arranged in the manner previously described. The conveyor  19  receives single length filter units  17  from a first feed mechanism  27  and double length filter units  18  from a second feed mechanism  26 . The first and second feed mechanisms  27 ,  26  may be hoppers that contain the filter units  17 ,  18  and a mechanical gate on each hopper may deposit the filter units  17 ,  18  onto the conveyor  19  in the correct orientation and at the correct time, so that the filter units  17 ,  18  are arranged in end-to-end arrangement as required for producing the sleeve  1  with filter units, as shown in detail in  FIG. 2 . 
         [0065]    The conveyor  19  delivers the arranged filter units  17 ,  18  to a collator  20 , which is configured to bunch the filter units together, with no spaces between them, and to insert the collation into the continuous sleeve  28  which has been formed on the second process  12 . 
         [0066]    The second process  12 , which produces a continuous moulded sleeve  28  from a material  29  being fed from a reel  30 , is partly a web handling system for handling the web of material  29 ,  40  before it enters the sleeve forming process.  FIG. 4  shows the web of material  29  for the sleeve being provided from a reel  30 . It will be appreciated that instead of a reel  30  to provide the material  29 , the material may be fed directly into the second process line  12  from another machine, such as an extrusion forming machine that produces the web of material. The material  29  from the reel  30  is a web with fixed width and can be controlled using rollers  31  which move to control the tension, speed and/or the position of the material  29  as it travels through the subsequent apparatus for forming a continuous sleeve and inserting the filter units. 
         [0067]    As previously explained, the second process line  12  may include a material preparation process  22  (see  FIG. 3 ) which alters the material prior to the material entering the moulding process. For example, the process may include a preparation cutter assembly  32  which cuts a profile into the material  29 . For some embodiments of the sleeve, such as that shown in  FIGS. 1 and 2 , it is necessary to add a profile to the edges of the material to form the profiled edges  5 ,  6  of the opening  4  once the sleeve is formed (see  FIG. 1 ). The material preparation cutter assembly  32  may be omitted if no profile edge is required—i.e. if the opening  4  (see  FIG. 3 ) along the sleeve has straight parallel edges. Alternatively, a similar material preparation process may be used to change the width of the reel of material and therefore adjust the size of the opening along the sleeve, as will become apparent. 
         [0068]      FIG. 5  shows a preparation cutter assembly  32  which can be used to cut the edges  33  of the material  29  as it is unwound from the reel  30 , or from a previous process, before it is moulded into a continuous sleeve. The material  29  passes through the preparation cutter assembly  32  which comprises a cutter roller  34  and an anvil roller  35  that act against each other with the material  29  travelling between them as they rotate in opposite directions. The outer circumferential surface  36  of the cutter roller  34  has two blades  37  protruding radially outwards that act against the outer circumferential surface  38  of the anvil roller  35  to shear cut the material  29  as it passes between the two rollers  34 ,  35 . In the example shown, the blades  37  cut the material  29  to remove the edge portions  39  and the shape of the blades  37  defines the profile of the cut edges  40  of the cut material  41  and therefore the opening  4  (see  FIG. 1 ) of the sleeve. The waste material—the two edge strips  39  which have been removed—may be wound onto a separate collection roller or fed directly into a chute for disposal or recycling. 
         [0069]    In an alternative arrangement, the material preparation process using the preparation cutter assembly may be carried out separately to the second process line  12  (see  FIG. 4 ). In this case, a separate machine would prepare the cut material  41  which is then re-wound, onto a reel, which can be transferred to the sleeve forming apparatus to feed the cut material  41  directly into the sleeve forming apparatus. 
         [0070]    The cutter and anvil rollers  34 ,  35  of the preparation cutter assembly  32  may be changeable to alter the configuration of the blades  37  and therefore change the form of the profiled edges  40  of the formed sleeves. The cutter and anvil rollers  34 ,  35  may also be able to move apart on the machine, for example by means of a pneumatic actuator (not shown). This will allow the preparation cutting process  22  to be selectively disabled, by allowing the material  29  to pass between the rollers  34 ,  35  without being cut. This may be appropriate if a single apparatus were to be used to produce different embodiments of sleeves with no edge profile required on the opening of the sleeve. 
         [0071]    Referring again to  FIG. 4 , the cut material  41  then enters the sleeve moulding apparatus  42 , which moulds the material into a continuous sleeve with a continuous opening along one side and is shown in more detail in  FIGS. 6 a  and 6 b   . A die  43  moulds the flat, cut material  41  into a substantially tubular continuous sleeve  28  with a continuous opening along one side. 
         [0072]    The die  43  shown in  FIGS. 6 a  and 6 b    is a steam die that heats the cut material  41  using steam and the internal shape of the die, through which the material  41  is drawn, moulds the heated material into a substantially tubular sleeve  28  with an open side. The die  43  is formed of first and second parts  44 ,  45 ; the first part  44  is in a fixed position and the second part  45  can be moved towards and away from the fixed first part  44  by means of a pneumatic actuator  46 . The first and second parts  44 ,  45  of the steam die  43  each have a recess  47 ,  48  and those recesses are aligned when the die  43  is dosed to create a tapered tubular pathway  49  through which the material  41  is drawn. The tubular pathway  49  has a tapered inlet which leads into tubular portion. 
         [0073]    Furthermore, the second part  45  of the steam die  43  has an arm  50  (see  FIG. 6 b   ) that extends around to the inlet side of the recess  47  in the second part  45  and supports a tapered moulding pin  51  that extends into the tubular pathway  49  formed by the recesses  47 ,  48  when the first and second parts  44 ,  45  of the steam die  43  are closed together. The pin  51  is shaped to match the form of the tapered tubular pathway  49 , with a tapered portion that is aligned with the tapered inlet of the pathway  49  and a cylindrical portion that extends through the tubular portion of the pathway  4 . The pin  51  sits concentrically within the tubular pathway  49  so that it does not contact the edges of the recesses  47 ,  48 . In this way, the material is drawn through the annular space between the pin  51  and the edges of the recesses  47 ,  48  and this space defines the tubular shape of the continuous sleeve  28 . 
         [0074]    A steam conditioning unit (not shown) supplies steam to the die  43  via an inlet pipe  52  and the recesses  47 ,  48  and/or the pin  51  have at least one outlet aperture (not shown) that releases steam into at least a part of the tapered tubular pathway  49 , directly onto the material  41  as it is drawn through the die  43 . The steam acts to heat the material  41  which causes it to more readily plastically deform into the shape defined between the tubular pathway  49  and the moulding pin  51 . The material  41  deforms into a substantially tubular shape as it is drawn through the die  43  so that the edges  40  (see  FIG. 5 ) of the material  41  are folded towards each other but do not make contact, leaving a continuous opening along one side of a continuous moulded sleeve  28 . The edges of the opening are the same as the edges which were cut by the material preparation cutter assembly  32  (see  FIG. 5 ) and therefore may have a profile, as shown in  FIGS. 1 and 2 . 
         [0075]    Referring again to  FIG. 4 , as the moulded continuous sleeve  28  exits the steam die  43  it begins to cool and the form of the moulded sleeve  28  is maintained as the material returns to a predominantly elastic condition. As shown in  FIG. 6 c   , a cooling unit  53  may be provided immediately after the die  43  to accelerate the rate of cooling and ensure that the moulded form of the sleeve  28  does not deteriorate during subsequent processes due to residual heat which may maintain plastic behaviour in the sleeve  28 . 
         [0076]    The cooling unit comprises a funnel shaped body with an internal chamber through which the continuous sleeve  28  passes immediately or almost immediately after it leaves the steam die  43 . The sleeve  28  enters the funnel shaped chamber via the narrow end  54  and exits via the larger, open end  55  of the funnel. The funnel shaped chamber  53  comprises a high pressure air inlet  56  which provides cool air to the interior of the chamber  53  and directly onto the continuous sleeve  28  to carry heat away from the sleeve and cool it. 
         [0077]    Referring again to  FIGS. 3 and 4 , the moulded and cooled continuous sleeve  28  then enters the combining process  14  which opens the continuous sleeve  28  by enlarging the opening before the collated filter units  17 ,  18  are inserted into the sleeve via the enlarged opening. The combining process  14  uses a combining apparatus which includes a cylindrical former  56 , a sleeve retaining assembly  57  and the collator  20 . 
         [0078]    The combining apparatus is shown in more detail in  FIGS. 7 a  and 7 b   . The cylindrical former  56  is configured so that the continuous and cooled sleeve  28  travels over and around the cylindrical former  56  along an arcuate path through an angle of, for example at least 30 degrees, or more preferably about 90 degrees, as shown in  FIGS. 4 and 7 . The sleeve  28  is received on the cylindrical former  56  with the continuous opening  58  facing outwards, away from the former  56 , so that the opening  58  faces radially away from the longitudinal axis of the former  56 . The opening  58  is positioned on the opposite side of the sleeve  28  to that which contacts the cylindrical former  56 . This can be achieved by orientating the material reel  30  and steam die  43  (see  FIG. 4 ) such that the sleeve  28  is formed with the continuous opening in the correct orientation for being received on the cylindrical former  56  in the above described manner, as shown in  FIG. 7   a.    
         [0079]    As the continuous sleeve  28  travels around the cylindrical former  56  the sleeve is deformed and folded backwards on itself which causes the opening  58  along the sleeve to be widened so that the sleeve  28  is at least partially flattened into an open position  59 , as shown in  FIG. 7 b   . The extent to which the continuous opening  58  is enlarged or widened, and therefore the extent to which the sleeve  28  is flattened, will be determined by the radius of the cylindrical former  56 , the angle through which the sleeve  28  is turned and the profile of the circumferential face of the former  56 . For example, the cylindrical former  56  may be configured to only widen the opening  58  by the minimum amount required to insert the collations filter rods through the opening. Alternatively, the sleeve  28  may be almost completely flattened. 
         [0080]    As shown in  FIG. 8 , the collating drum  25  pushes the arranged filter units from the conveyor  19  onto the opened sleeve  59  as it passes over the cylindrical former  56 . The collated filter units are thereby inserted into the continuous sleeve through the enlarged opening  58  and the collating drum  25  ensures that the filter units are driven into the sleeve  59  so that there is no space between the filter units. 
         [0081]    As the opened sleeve  59  leaves the cylindrical former  56  it is no longer travelling in an arcuate path and the resilient and elastic properties of the sleeve material may cause the sleeve  59  to naturally return to the original non-deformed configuration that was defined during the moulding process  23  (see  FIG. 3 ). Therefore, to ensure that there is sufficient time for the filter inserts to be properly collated and inserted into the sleeve  59 , the opened sleeve may be maintained in the open, deformed position for at least a short distance. In other words, a region of the sleeve is maintained in the deformed configuration as it leaves the cylindrical former  56  to provide enough time and space to insert the collation of filter inserts. Furthermore, it is preferable to control the closing movement of the opened sleeve  59  because the natural movement of the sleeve from the deformed and opened form  59  to the non-deformed form  62  (see  FIG. 9 c   ) may be unpredictable and could damage the material of the sleeve and/or dislodge the collated filter units positioned on the opened sleeve  59 . 
         [0082]    Referring to  FIGS. 4, 9   a ,  9   b ,  9   c  and  9   d , the apparatus includes a sleeve retaining assembly  57  that comprises a support plate  60  and a retaining plate  61  to retain the sleeve  59  in the open position after the sleeve exits the cylindrical former  56 . This provides some time for the collated filter units  9  to be fed into the opened sleeve  59 . 
         [0083]      FIGS. 9 a , 9 b  and 9 c    show cross sections of different embodiments of the sleeve retaining assembly  57 . Each embodiment has a support plate  60  and retaining plate  61  with the opened sleeve  59  and filter inserts  9  located between the two plates  60 ,  61 . The sleeve  59  and filter units  9  are moving through the assembly, between the support plate  60  and retaining plate  61 , which combine to prevent the sleeve from returning to the non-deformed, moulded configuration over a short distance while the filter inserts  9  are inserted. 
         [0084]    The retaining plate  61  of the embodiment shown in  FIG. 9 a    comprises a central longitudinal groove  63  through which the collation of filter units  9  moves and the internal surfaces either side of the groove  63  hold the sleeve  59  in the open position by preventing the edges from moving back into the non-deformed configuration. 
         [0085]    The embodiment shown in  FIG. 9 b    has a retaining plate  61  that is formed of two individual flat plates  61   a,    61   b  that are separated to provide a space  63  along which the collated filter inserts  9  freely travel on the opened sleeve  59 . 
         [0086]    The embodiment of  FIG. 9 c    has a support plate  60  which comprises an inwardly tapered or concave surface  64  to ensure that the collation of filter units  9  and the opened sleeve  59  are maintained in a central position between the support plate  60  and retaining plate  61 . 
         [0087]    The sleeve  59  is only held in the open position for the distance required to insert the filter units  9  in the desired manner. Therefore, after a short distance between the support plate  60  and the retaining plate  61 , the sleeve  59  is allowed to return to its moulded configuration  62  (see also  FIG. 4  ). As shown in  FIG. 9 d   , the exit end  65  of the sleeve retaining assembly  57  may have a tapered portion  66  on either side of the groove  63  that gradually allows the edges of the opened sleeve  59  to move upwards and envelop the filter rods  9  to re-form the moulded sleeve  62  with filter rods  9  within. As explained earlier, this more gradual return to the moulded configuration  62  may be preferable to a sudden and instant release which could disturb the arrangement of filter units  9  or could damage the sleeve material. 
         [0088]    Referring again to  FIG. 4 , depending on the material of the sleeve, machine running speed and other factors such as the diameter of the cylindrical former  56 , the open, flattened sleeve  59  may not return to the non-deformed, moulded configuration due to the elastic properties of the material alone. In this case, a garniture  67  and/or a heater  68  may be provided to re-form the flattened sleeve  59  into the continuous sleeve  62  to envelop the filter units  9 . As shown in  FIG. 4 , this optional garniture  67  may be positioned downstream of the sleeve retaining assembly  57 . 
         [0089]    The garniture  67 , as shown in  FIG. 10 , has a tapered inlet  69  which leads onto a semi-tubular groove  70  through which the flattened sleeve  59  enters the garniture  67 . The form of the tapered inlet  69  causes the edges of the flattened sleeve  59  to move upwards and garniture plates  71 ,  76  fold the edges over to re-form the non-deformed moulded sleeve  62  around the filter rods  9 . The garniture plates  71 ,  76  comprise tapered surfaces that push the sleeve into the required shape as the sleeve is drawn through the garniture  67 . 
         [0090]    Depending on the characteristics of the material being used to form the sleeve, a garniture with a similar configuration to that described may be used to control the natural elastic movement of the sleeve back into the non-deformed configuration. For example, instead of the garniture being configured to push the sleeve material, the garniture plates may be configured to restrict the movement of the sleeve material so that the sleeve pushes against the garniture plates and is gradually released into the non-deformed configuration. This may be used to avoid the sudden release of the sleeve material which may damage the material and/or dislodge the filter units. 
         [0091]    Furthermore, the garniture  67  may also include one or more heaters  68  to heat the flattened sleeve  59  as it enters the garniture  67  to induce plastic behaviour in the sleeve material to ease the re-forming process. 
         [0092]    Referring again to  FIG. 4 , after the sleeve  62  has been reformed around the filter units  9 , either by natural elasticity or by a re-forming apparatus, the continuous sleeve  62  enters a cutter  72 . As previously explained, the cutter  72  is configured to sever the continuous sleeve  62  and the filter units  9  into the individual products shown in  FIG. 2 .  FIG. 11  shows the sleeve as it enters the cutter, with dotted lines  75  representing the cutting locations along the sleeve  62 . The timing of the cutter  72  is dependent on the timing of the collating drum  25  (see  FIG. 4 ) such that the cutter  72  severs the continuous sleeve  62  in locations corresponding to the middle of each double length filter rod  73 . In this way, the individual sleeves  1  are separated from the continuous sleeve  62  and the double length inserts  73  are cut into single length inserts  74 , which are located at the ends of each sleeve product  1 . The cutter  72  may include a rotary blade, guillotine or other cutting mechanism to sever the sleeve  62  and double length filter units  73  quickly and cleanly. 
         [0093]    In order to address various issues and advance the art, the entirety of this disclosure shows by way of illustration various embodiments in which the claimed invention(s) may be practiced and provide for superior manufacture of sleeves holding elongate elements. The advantages and features of the disclosure are of a representative sample of embodiments only, and are not exhaustive and/or exclusive. They are presented only to assist in understanding and teach the claimed features. It is to be understood that advantages, embodiments, examples, functions, features, structures, and/or other aspects of the disclosure are not to be considered limitations on the disclosure as defined by the claims or limitations on equivalents to the claims, and that other embodiments may be utilised and modifications may be made without departing from the scope and/or spirit of the disclosure. Various embodiments may suitably comprise, consist of, or consist essentially of, various combinations of the disclosed elements, components, features, parts, steps, means, etc. In addition, the disclosure includes other inventions not presently claimed, but which may be claimed in future.