Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65B—MACHINES, APPARATUS OR DEVICES FOR, OR METHODS OF, PACKAGING ARTICLES OR MATERIALS; UNPACKING
  • B65B11/00—Wrapping, e.g. partially or wholly enclosing, articles or quantities of material, in strips, sheets or blanks, of flexible material
  • B65B11/02—Wrapping articles or quantities of material, without changing their position during the wrapping operation, e.g. in moulds with hinged folders
  • B65B11/025—Wrapping articles or quantities of material, without changing their position during the wrapping operation, e.g. in moulds with hinged folders by webs revolving around stationary articles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65B—MACHINES, APPARATUS OR DEVICES FOR, OR METHODS OF, PACKAGING ARTICLES OR MATERIALS; UNPACKING
  • B65B45/00—Apparatus or devices for supporting or holding wrappers during wrapping operation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65B—MACHINES, APPARATUS OR DEVICES FOR, OR METHODS OF, PACKAGING ARTICLES OR MATERIALS; UNPACKING
  • B65B11/00—Wrapping, e.g. partially or wholly enclosing, articles or quantities of material, in strips, sheets or blanks, of flexible material
  • B65B2011/002—Prestretching mechanism in wrapping machines
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65B—MACHINES, APPARATUS OR DEVICES FOR, OR METHODS OF, PACKAGING ARTICLES OR MATERIALS; UNPACKING
  • B65B2210/00—Specific aspects of the packaging machine
  • B65B2210/14—Details of wrapping machines with web dispensers for application of a continuous web in layers onto the articles
  • B65B2210/18—Details of wrapping machines with web dispensers for application of a continuous web in layers onto the articles the web dispenser being mounted on a rotary ring

Definitions

• the present invention relates to a wrapping apparatus of individual items by means of a thin film of stretchable plastic material.
• a wrapping apparatus of individual items by means of a thin film of stretchable plastic material.
• the invention relates to an apparatus for the wrapping with stretchable plastic film with an improved holding device.
• packaging of items can be done by wrapping said items with a winding of thin plastic film.
• this last technique is used on machines which wind the items to be packaged with one or more coils of stretchable film, preferably pre-stretched .
• the winding occurs defining a relative rotation of a reel of plastic film around the item to be wrapped, establishing a relative movement between the reel and the item along a movement axis for determining winding coils distributed on a certain length .
• the winding may occur according to a vertical axis (for example in conventional pallet wrappers) , along which the load to be wrapped is arranged standing, or according to a horizontal axis, along which the items to be wrapped are caused to move forward.
• each item is fed to the wrapping station along a conveyor belt or a roller conveyor, halted in this station, then it is wound by the film and then caused to continue on the conveyor belt of the wrapping line.
• a reel-holding car ⁇ riage which is caused to move along a circular line, arranged in the wrapping station according to a plane oriented perpendicularly to the supply line of the items and which horizontally encircles the conveyor belt.
• the item is supported exclusively on overhanging guiding means (typically a shelf and any lateral containment rails) which connect the supply portion of the conveyor belt with a moving-away portion.
• overhanging guiding means typically a shelf and any lateral containment rails
• these guiding means are shaped and structured so as to favor the removal of the wrapped item.
• Critical steps of this wrapping process are the ini ⁇ tial and final ones, respectively, in which the film must be fastened to the item and then it must be severed to present it again to the subsequent item.
• it is typically resorted to a retaining and cutting grip- per, conventionally arranged below the overhanging guiding means, mounted moving in a longitudinal direction to the rotation axis of the reel-holding carrier.
• the rectilinear gripper with retaining axis arranged horizontally and aligned to the rotation axis of the film reel, has two cooperating jaws apt to retain a film edge and to also perform, in a position slightly downstream of the retaining line, a cut in the film.
• the in ⁇ itial end edge of the film is retained by the gripper - stationary in a fixed position - until the forming of at least part of a first film coil around the item to be wrapped, as the reel is displaced in rotation on the reel- holding carriage. In this movement, the film is partly wound on the item and tends to naturally adhere thereto, abutting in tension on the corners.
• this film rope is the result of an essential step for ensuring that the ini ⁇ tial end of film is not released prematurely, on the other hand, however, it makes up a lateral appendix of the wrap- ping, which disturbs the aesthetics and the functionality of the wrapping.
• the Applicant has al ⁇ ready proposed to make use of a temporary retaining device, apt to retain, by simple resting, the initial film edge to the item to be wrapped. This device supplements the action of the gripper and allows to disengage the gripper in use ⁇ ful time, without it dragging with it the film, despite maintaining the initial edge adherent to the item for the time necessary to complete at least one coil.
• This tempo ⁇ rary retaining device is in the form of a pressure rod, which rests outside the plastic film, pushing it against the item, so as to retain it in position.
• the shape of the provisional retaining device is such that it can then be taken off the coils, without leaving trace in the wrapping.
• This handling control is complex and a possible source of adjustment and control problems.
• EP0713828 further discloses gripping device relying on suction action to retain an edge of the plastic film far from the item to be packaged. This device is always kept outside the path affected by the plastic film reel and hence is not affected in any manner by the technical prob- lems summarized above, which are specific of a wrapping ma ⁇ chine having an horizontal feeding line and a film reel brought in rotation around said line.
• the problem at the basis of the invention is therefore that of proposing an apparatus and a wrapping procedure as above, which allows to achieve an ongoing winding of stretching film, with the smallest complexity possible in the operation of the temporary retaining device.
• a wrapping apparatus employing stretching plastic film for items to be wrapped, comprising entry line and exit line, which define a horizontal feeding line, having an enter path to and an exit path from a wrapping station provided with a drive ring apt to bring in ro- tation a reel of said stretching film around said horizontal feeding line, and a holding gripper apt to temporarily hold an initial edge of said film in a starting step of the rotation of said reel, wherein it is also provided a tempo- rary retaining device of said film comprising a stationary hollow elongated suction member arranged with a longitudinal axis thereof parallel to said exit path and having an inner longitudinal side located so as to end up just oppo- site an item to be wrapped during the permanence in the wrapping station, and an outer longitudinal side provided with at least an air suction intake.
• the hollow elongated mem- ber has a flattened transversal section and has a single intake in the shape of an elongated slit.
• a net having small mesh is laid on the inner side of said hollow member, covering said slit.
• the net can have a mesh of 0,2x0,2 mm and the slit a width of 2 mm.
• the elongated hollow member is mounted cantilevered on a small support frame fastened upstream of said drive ring.
• the posi ⁇ tion of said elongated hollow member, with respect to said feeding line, is adjustable.
• said elongated hollow member is arranged preferably on the side of the feeding line which is closest to said holding gripper with respect to the movement direc- tion of said reel.
• a wrapping method for wrapping items employing stretching plastic film comprising
• a temporary retaining device of said film comprising a stationary hollow elongated suction member arranged with a longitudinal axis thereof parallel to said exit path and having an inner longitudinal side located just opposite and brushing the item to be wrapped during the permanence in the wrapping station,
• fig. 1 is a perspective overall view of an exemplify- ing winding apparatus provided with a device according to the invention
• fig. 2 is a detail view of fig. 1, wherein an embodi ⁇ ment of the invention is shown;
• fig. 3 is a side elevation view of a sucking device according to a preferred embodiment of the invention.
• fig. 4 is a enlarged view of the detail in the square A of fig. 3.
• a stretching- film wrapping apparatus comprises an entry line la, for ex ⁇ ample a slide or a roller conveyor along which the items to be wrapped are caused to move forward, a wrapping station W and an exit line lb, itself in the form of a slide or roll ⁇ er conveyor.
• the items move from entry line la to exit line lb, crossing wrapping station W, along a straight line or according to a different path.
• the entry line is arranged at 90° with respect to the axis crossing wrapping station W: the items arrive in the proximity of the wrapping station along a sliding plane and then they are pushed crosswise, through station W, by a pushing device S.
• shelf 2 projects in a cantilever manner through the wrapping station and ends at a short distance from the moving-away portion of exit line lb (as clearly detectable in fig. 2) .
• Shelf 2 has in- deed the function of supporting the item during the winding with the stretching film and, at the same time, of easing the translation thereof towards the moving-away portion of exit line lb despite the application of coils of plastic wrapping film.
• shelf 2 is preferably aided by one or more upper rails 3, which limit laterally the item during the translation and winding thereof with the film.
• shelf 2 with rails 3 will be referred to in the following as guiding means.
• a control ring 4 is provided, in a way known per se, rotatably mounted - through a plurality of guiding wheels 4a fastened to a base frame - on a plane perpendicular to the progress direction of the items.
• control ring 4 brought in rotation through a suitable mo ⁇ torization (not shown in detail) , a carriage 5 is mounted integral, whereon a shaft 6 is installed supporting a reel of stretchable plastic film and a relative pre-stretch as ⁇ sembly.
• gripper 7 gripping the initial end of film P, which unwinds off the reel.
• gripper 7 performs the double function of retaining the initial edge of film, as well as of severing it when it must be separated from the remaining film wound on the wrapped item.
• gripper 7 is suitably shifted, according to ways known per se, to grip again the film stretched between the reel and the wrapped item and thus retain the new ini ⁇ tial edge of the subsequent wrapping.
• gripper 7 In the following no further details on gripper 7 will be provided, since the layout thereof is widely known and, per se, it does not form an object of the present inven ⁇ tion.
• a temporary retaining device of the plastic film is furthermore provided, regardless of gripper 7, arranged in a position meant to be adjacent at a short distance to a surface of an item when it is in the winding station.
• such a retaining device consists of elongated hollow member 8, pre ⁇ ferably flattened, arranged with the longitudinal axis the- reof according to the progression axis of the items within wrapping station W.
• Hollow member 8 shaped as a rod, has an inner side, meant to end up just opposite to the item during the permanence thereof in wrapping station W, and an outer side provided with at least intake means 8a.
• a single in ⁇ take means is provided in the shape of a slit 8a elongated in the longitudinal direction of hollow member 8, but it is not ruled out to be able to provide a series of small aligned holes or other.
• the rectilinear slit has proven the most advantageous one, because it produces a good intake and retaining effect of the film, without causing tearing in the same.
• the intake means where vacuum is operated through the hollow member 8 are in the shape of a rectilinear slit provided on the inner side with a net having small mesh.
• a metal ⁇ lic net having a small mesh is laid on the inner side of the hollow member 8 to cover the slit.
• small it is here meant a mesh having a size smaller then the transversal size of the elongated slit.
• the net has a mesh of 0,2x0,2 mm and the slit has a width of 2 mm .
• Figs. 3 and 4 disclose a further embodiment where two parallel lines of narrow slit segments are provided, the slit segments belonging to the two lines being staggered each other.
• Hollow member 8 is connected at the base thereof to a vacuum intake socket, such as to bring into depression an inner cavity thereof and hence cause an intake flow in cor- respondence of intake means 8a.
• the crosswise dimension of elongated hollow member 8 is chosen as compromise between the lesser bulk and an acceptable sizing of the inner cavity, in order not to have a high pressure loss on the intake flow, as well as a suita ⁇ ble resistance of the structural walls.
• hollow member 8 has a rectangular tubular section, for example of the size 20x10 mm with thickness 1.5 mm.
• elongated hollow member 8 is mounted cantilevered on a small support frame 9, said frame fastened to the apparatus in the proximity of the base of shelf 2.
• the temporary retaining de- vice with intake means is steadily mounted - that is, with ⁇ out handling and/or control during operation of the wrap- ping station - upstream of the wrapping station and projecting cantilever-like in the area affected by the move ⁇ ment of the spool of plastic film.
• elongated hollow member 8 is installed on the side of the item which is first invested by the plastic film coming from the grip ⁇ per 7 during the winding movement of the reel.
• elongated hollow member 8 is installed on the side which is nearest to holding gripper 7 with respect to the movement path of the reel.
• the reel is always found in a position next to holding gripper 7, typically on one of the two sides (depending on the winding direction) of the item progression line: if this is defined as starting side, elongated hollow member 8 is mounted on this same starting side.
• the position of temporary retaining device 8 is stable, the size of items to be wrapped being the same, but can be adjusted differently (moving supporting frame 9 with respect to the frame of the apparatus) between one cycle and the other, upon the varying of the dimensions of the items to be wrapped.
• the inner side of elongated hollow member 8 is found just opposite and brushing against an item during the wrapping, so as to offer the least bulk possible between the item and the film coils which are wound thereon.
• hollow suction member 8 At the end of the winding, air intake through hollow suction member 8 is interrupted, so that the film is no longer retained on the outer side of the temporary retaining device.
• the item can thus be pushed forward, on exit line lb, and the film coils will smoothly come off from re- taining device 8 and from guiding means 2 and 3 - longitu ⁇ dinally aligned with the exit path - which, for the pur ⁇ pose, may be coated with a low-friction material. Due to the minimum crosswise bulk of hollow member 8, the coils of plastic film nevertheless remain sufficiently taut on the wrapped package, taking up part of the elastic stretching.
• the device according to the invention is perfectly achieved.
• the gripper must no longer intervene to retain and stretch the initial edge of film, hence the unpleasant plastic rope no longer forms in the wrapping.
• the device of the invention is extreme- ly inexpensive and simple from a construction point of view, because it requires only one air suction line and im ⁇ plies no moving part: thus it may be applied to any winding apparatus, even an already existing one, without having to make significant structural changes.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Basic Packing Technique (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=50513974

Family Applications (1)

Country Status (5)

Families Citing this family (15)

Family Cites Families (20)

• 2015
  • 2015-02-12 WO PCT/EP2015/052922 patent/WO2015121334A1/en not_active Ceased
  • 2015-02-12 CN CN201590000296.5U patent/CN205906247U/zh not_active Expired - Lifetime
  • 2015-02-12 ES ES15706711.7T patent/ES2660450T3/es active Active
  • 2015-02-12 EP EP15706711.7A patent/EP3105124B1/de active Active
  • 2015-02-12 US US15/118,537 patent/US20170057673A1/en not_active Abandoned

Also Published As

Similar Documents

Legal Events