Method and system for wrapping an assembly of segments

Abstract

In the method and system for wrapping an assembly (5) of segments, an outer periphery of the assembly is affixed longitudinally to an edge portion of a piece of wrapping material (50) and at least one of the segments of the assembly is a rigid segment with a compressibility higher than about 10 Newton per 1.5 mm. The assembly of segments is provided to a rolling seat (10) arranged in the peripheral surface of a wrapping conveyor (1). A retaining surface (202) is arranged at a distance and opposite the peripheral surface of the wrapping conveyor, such as to contact the assembly supplied to the rolling seat with the retaining surface. The assembly of segments are wrapped by moving the wrapping conveyor relative to the retaining surface thereby creating a relative movement between the wrapping conveyor and the retaining surface such as to cause rotation of the assembly in the rolling seat along a longitudinal axis of the assembly and by providing the assembly of segments with a three-point guiding contact while moving the assembly of segments along the retaining surface.

Claims

1. System for wrapping an assembly of segments, the system comprising a supply conveyor, a wrapping conveyor and a retaining surface, wherein the supply conveyor is adapted for supplying an assembly of segments to the wrapping conveyor, the assembly of segments comprising at least two segments arranged in an end-to-end relationship with an outer periphery of the assembly being affixed longitudinally to an edge portion of a piece of wrapping material, wherein at least one of the at least two segments of the assembly is a rigid segment with a compressibility higher than about 10 Newton per 1.5 mm; wherein the wrapping conveyor comprises a rolling seat arranged in the peripheral surface of the wrapping conveyor being movable with the wrapping conveyor, the rolling seat comprising a rolling element rotatable relative to the wrapping conveyor for rotating the assembly in the rolling seat; wherein the retaining surface is arranged at a distance to and opposite the peripheral surface of the wrapping conveyor such as to contact the assembly arranged in the rolling seat of the wrapping conveyor, wherein the wrapping conveyor is movable relative to the retaining surface adapted to create a relative movement between the wrapping conveyor and the retaining surface such as to cause rotation of the assembly in the rolling seat along a longitudinal axis of the assembly, thereby providing the assembly with a three-point guiding contact while moving the assembly along the retaining surface and wrapping the assembly with the piece of wrapping material while the assembly is movable along the retaining surface, and wherein the system comprises a pressure applicator or applying pressure to the retaining surface to apply a constant pressure to the assembly.

2. System according to claim 1, further comprising a retaining device arranged in the wrapping conveyor for retaining the assembly in the rolling seat, the retaining device providing a retaining action onto the assembly while the assembly is arranges in the rolling seat.

3. System according to claim 1, wherein the rolling element comprises a pair of rollers arranged parallel to each other and rotatable in a same direction, the pair of rollers being arranged perpendicular to a moving direction of the wrapping conveyor.

4. System according to claim 1, wherein the retaining surface is a surface of an endless belt.

5. System according to claim 1, wherein the retaining surface and a surface of the rolling seat are surfaces adapted to avoid slippage between segments of the assembly of segments and the rolling seat.

6. A cigarette maker comprising a system according to claim 1.

Description

(1) The invention is further described with regard to embodiments, which are illustrated by the following drawings, wherein

(2) FIG. 1 shows the principle of a three-point guiding contact upon wrapping of an assembly of segments;

(3) FIG. 2 shows an embodiment of the system according to the invention for carrying out the method according to the invention.

(4) In FIG. 1 an assembly of substantially cylindrical segments 5, for example segments of a smoking article, is arranged in contact with and between two rolling wheels 100, such that the segments of the assembly lie in an end-to-end relation, either abutting with neighboring segments or with a predetermined or random spacing with neighboring segments. The two rolling wheels 100 form part of a rolling seat (not shown) arranged in the periphery of a rolling drum 1, for example a rolling drum 1. Assembly 5 contacts each of the two rolling wheels 100 in one contact location 50. Preferably, the contact location 50 is a contact line extending along the periphery and along the longitudinal extension of assembly 5.

(5) A retaining surface 202, for example the surface of a conveyor belt, is arranged at a distance and substantially parallel to the periphery of rolling drum 1. The distance is chosen and adapted to the diameter of assembly 5. The distance is further chosen such that retaining surface 202 contacts assembly 5 in a third contact location 50. The three contact locations 50 are distanced from each other and are arranged on the circumference of assembly 5. The one contact location by the retaining surface 202 is arranged basically opposite the two other contact locations provided by the two rolling wheels 100. Depending on the arrangement of rolling wheels 100, the three contact locations 50 may be arranged substantially equidistantly on the circumference of assembly 5.

(6) Rolling drum 1 and retaining surface 202 are moved relative to each other. If retaining surface 202 is moved as well, it is preferably moved in a similar direction as wrapping conveyor but preferably not at a same speed. Retaining surface 202 may for example not be moved at all, but is preferably moved at a lower speed than the rotational speed of rolling drum 1. By the relative movement of rolling drum 1 and retaining surface 202, assembly 5 is made to rotate between the two rolling wheels 100 in the rolling seat along its longitudinal axis (perpendicular to the drawing sheet). At the same time assembly 5 is guided by the two rolling wheels 100 and retaining surface 202. One or both of rolling wheels 100 may be driven wheels to make the assembly rotate in the seat or to support such a rotation. The rotational direction of assembly 5 and of rolling wheels 100 are indicated by arrows. Alternatively, the rotation of the assembly 5 occurs solely due to the difference in speed between the rolling drum 1 and the retaining surface 202. In FIG. 1 rolling drum 1 is moved in a clockwise direction. By the rotational movement of assembly 5, a piece of wrapping paper, which is fixed longitudinally to the outer periphery of the assembly (not shown in the drawing) is made to wrap around the assembly 5. An adhesive applied to the piece of wrapping paper enables the paper to remain attached to assembly 5. By the three-point guiding contact such a wrapping is guided and controlled during the entire wrapping process. By this, different kind of segments may be provided in the assembly, and especially also rigid segments are reliably wrapped. In addition, performing wrapping while assembly 5 remains in the rolling seat prevents misalignment of individual segments of assembly 5, which might otherwise occur when rolling several segments freely or without close guidance along a plane.

(7) FIG. 2 shows an embodiment of a system by which a three-point guiding contact upon wrapping of an assembly arranged in a rolling seat may for example be realized.

(8) On a supply drum 3 a plurality of assemblies of segments 5 are held, preferably by suction. Assemblies 5 may for example comprise at least two segments as used in the manufacture of smoking articles. Each assembly 5 presents on its outer periphery a projecting strip of wrapping material 50 fixed to the assembly. The segments of assembly 5 are arranged in an end-to-end relationship on supply drum 3 in respective seats 30. Supply drum 3 rotates anticlockwise as indicated by an arrow. The assemblies provided with the piece of paper are supplied to the rolling drum 1 at transfer location 31.

(9) After having been wrapped while on the rolling drum 1 the wrapped assemblies 5 are transferred to a receiving drum 4 at transfer location 41 located downstream of transfer location 31. Receiving drum 4 is adapted to successively receive wrapped assemblies 5 from rolling drum 1.

(10) Rolling drum 1 is mounted to rotate clockwise, while receiving drum 4 is mounted to rotate anticlockwise. The rotational axis of the supply drum 3, the rolling drum 1 and the receiving drum 4 are arranged parallel to each other.

(11) Rolling drum 1 presents a number of equally spaced, peripherally arranged rolling seats 10. Each of the rolling seats 10 is adapted to receive, to retain a respective assembly 5 and for releasing the assembly 5 at transfer location 41. Each assembly 5 may be rotated about its longitudinal axis in the rolling seat 10. Strip 50 provided or coated with an adhesive is wrapped around assembly 5 by rolling drum 1 and a retaining surface 202 of a continuous belt 20 to secure the segments of the assembly to each other as described further below.

(12) Rolling seats 10 of rolling drum 1 communicate inwards via holes 110 with vacuum chambers 111,112 provided in the rolling drum. Vacuum chambers 111,112 are connected to suction means as known in the art and provide suction to the rolling seats 10 to retain assembly 5 in seat 10. A first suction chamber 111 extends from transfer location 31 to a contact location 200 of assembly 5 with retaining surface 202. A second suction chamber 112 extends from a contact end location 201 with retaining surface 202 to transfer location 41.

(13) Each rolling seat 10 comprises a pair of rollers 100 which may be driven. The rolling seats rotate clockwise in the shown embodiment. Rollers 100 are separated by a distance approximately equal to but no greater than the diameter of an assembly 5. They define a respective rolling seat 10 communicating with vacuum chambers 111, 112 and respective holes 110 via an opening 101 between the two rollers 100.

(14) Each roller 100 is defined externally by a rough cylindrical surface 1000 (shown in the enlarged view of FIG. 2), preferably an axially knurled surface, where the knurls are preferably arranged substantially tangential to the peripheral surface of rolling drum 1 and retaining surface 202.

(15) In use, assemblies 5 are transferred successively from supply drum 3 to rolling drum 1 at transfer location 31. The assemblies are withdrawn by suction into a respective seat 10 located in rolling drum 1. To simplify a transfer, any vacuum that may have been applied to the assemblies 5 while being on the supply drum 3 is interrupted as transfer location 31.

(16) The suction applied to rolling seats 10 additionally ensures that each assembly 5 is positioned with its outer surface contacting outer surfaces 1000 of rollers 100, once the assembly 5 is positioned to close opening 101 in the respective seat 10. A respective paper strip 50 contacts and rests along the periphery of the rolling drum 1 between two seats 10.

(17) A retaining device 2 providing retaining surface 202 to retain and guide the assemblies 5 in rolling seat 10 during wrapping is arranged between transfer locations 31 and 41. A mounting plate 211 comprises an arcuate slot 210, wherein the rotational axis of rolling drum 1 coincides with the center of curvature of arcuate slot 210. A first roller 21 is mounted in the slot 210. First roller 21 is movable to any desired position along arcuate slot 210 and may be fixed there. Mounting plate 211 may permit a lateral positioning of the mounting plate relative to rolling drum 1 to be adjusted. Mounting plate 211 also supports one end of a bracket 250 mounted thereon to be pivotable about a horizontal axis and carrying at its free end tension rollers 251,252. A spring may bias bracket 250 away from rolling drum 1. An additional pressure roller 24 may also be mounted to mounting plate 210 in a spring biased manner to push pressure roller 24 upwards into the direction of rolling drum 1.

(18) A driver roller 22 is mounted above pressure roller 24. A continuous belt 20 extends in a loop around the first roller 21, over the top of tension roller 252, around tension roller 251, and around driver roller 22. The tension roller 251 is configured such that the belt 20 rests against the periphery of rolling drum 1 in the absence of assemblies on rolling drum 1.

(19) An alternate embodiment comprises an addition of nip roller 23 by which the system according to the invention may be optimized for wrapping assemblies of non-uniform cross sections, such as oval cross-section cigarettes. Nip roller 23 is mounted for rotation beneath endless belt 20 to slightly narrow the gap between belt 20 and rolling drum 1. Nip roller 23 is located along the length of the gap such that each assembly that passes along retaining surface 202 traverses the gap. Preferably, a wrapping paper 50 overlap seam is radially aligned with nip roller 23 at the point where the nip roller 23 makes line contact with belt 20. The slight additional pressure exerted by nip roller 23 is of short duration. The pressure applied to the assembly 5 by the nip roller 23 is exerted substantially only along the wrapping paper overlap seam, and configured to be insufficient to permanently deform assembly 5 from its previous cross-sectional shape or to damage a segment of the assembly, respectively, but large enough to properly adhere the end of the wrapper onto the assembly.

(20) Belt 20 is driven to move in the same direction as the adjacent periphery of the rolling drum 1, but at a different angular speed as measured about the rolling drum axis. As a result of this difference in speed, an assembly 5 in rolling seat 10 of rolling drum 1 and retaining surface 202 of belt 20 is caused to rotate in the seat 10 while being moved forward with rolling drum 1 and arranged between rolling drum 1 and belt 20 by the drum's rotation.

(21) When supply drum 3 transfers assembly 5 to rolling drum 1 a strip of wrapping paper 50 is received within the seat 10 and starts trailing the assembly. To wrap the paper 50 around assembly 5, belt 20 is driven so that its angular speed is less than that of rolling drum 1, causing the assemblies to rotate in seat 10 counterclockwise in FIG. 2. The instant each assembly 5 contacts surfaces 1000 of rolling wheels 100 and retaining surface 202, assembly 5 is rotated. By this, strip 50 is preferably completely wrapped around assembly 5, while assembly 5 is moved along retaining surface 202. Thereby, the wrapping process is continuously guided by assembly 5 being in contact at the three contact locations (two rollers 100, one retaining surface 201).

(22) The tension in belt 20 may be maintained constant by means of tension roller bracket 250. As a result, the pressure that belt 20 exerts on assembly 5 is substantially constant, even if assembly 5 has a non-uniform cross section.

(23) Heating elements (not shown) of a known type may be provided in the rolling drum 1 or in the retaining device 2, for example arranged next to a nip roller 23 to support in activating or curing of the adhesive to achieve rapid adhesion.

(24) The wrapping time of each assembly 5 is preferably at most equal to the time taken by the respective seat 10 to travel along retaining surface 202. As such the wrapping time is still a function of the operating speed of at least rolling drum 1. However, the speed at which each assembly 5 is rotated about its axis is much less than the rotational speed of rolling drum 1 and depends foremost on the speed differential between the rolling drum 1 and belt 20.

(25) The system and method according to the invention enable an assembly to be wrapped relatively slowly even while being moved through a wrapping system at a high speed. This permits the wrapping operation to be carried out sufficiently slowly to prevent damage to the products while maintaining a high production rate.