Machines and processes for folding, cutting and stacking napkins

Abstract

A machine (9) for folding, cutting and stacking napkins, comprising a feed station (10), a folding drum (14) pivoted about a horizontal axis of rotation and provided with a circumferential groove, a blade (16) and a pair of spacers (18), the spacers having fingers (20) configured to stably support the napkins (13) downstream of the blade (16) relative to a horizontal plane perpendicular to the direction of travel, the folding drum (14) being provided with a circumferential groove (15) for inserting the spacers (18).

Description

Technical Field

[0001] The present invention is generally in the field of sheet product processing; in particular, the present invention relates to a machine and process for folding, cutting and stacking napkins. Background Art

[0002] Apparatus for manufacturing napkins is known comprising a station for feeding a continuous sheet of material to pairs of folding rollers arranged along a vertical axis of rotation.

[0003] As the sheet passes through the rollers, it is folded in a zigzag motion (in a known manner, for example by providing each roller with a radially convex profile and a radially concave groove angularly offset from one another, whereby at each turn the pin of one roller cooperates with the groove of the other roller, thereby pinching the sheet and folding it), thereby arranging itself downstream of the rollers in the form of a stack which, advancing in a horizontal feed direction, is pressed against a blade which cuts the stack into two identical parts containing a plurality of napkins.

[0004] A series of separators in the form of small brackets are also provided, which are inserted between the layers of the stack at intervals corresponding to the number of napkins intended to form a unit to be packaged. Said separators are driven passively by the stack as it moves in the feed direction, or by special motorized belts and slide on guides associated with the horizontal side members of the machine's support frame.

[0005] However, a machine configured in this manner has a large longitudinal footprint and further requires the rollers to exert a significant force on the advancing stack to cause the blades to penetrate it.

[0006] Also known are solutions in which the folding rollers are oriented along a horizontal axis so that, when the machine is in operation, the feed direction of the stack being formed is vertical. An example of this solution is known from FR 2932172 A1, which describes a device primarily suitable for cutting sheets of newsprint. This device provides sheets that are stacked one on top of another using the zigzag motion of the folding rollers, but the first layer downstream of the rollers is not compressed between them, allowing a separator to be inserted between one fold and the next. In order for the rollers to exert an appropriate pressure on the layers of sheet upstream of the cutting blades, the known device provides a complex mechanism whereby the separator is disengaged from its guide means (which are also integral to the machine frame) located downstream of the blades, while the upstream separator remains integral with the guide means. Summary of the Invention

[0007] One object of the present invention is to provide an alternative machine and process for folding, cutting and stacking napkins that is improved over the prior art. To this end, a spacer element having fingers is provided, which is movable so as to be arranged below the folding rollers and is suitable for supporting the stack during the downward feed movement towards and beyond the blade. Downstream of the blade, the spacer can unload a second stack of cut napkins (for example, by placing them on another platform capable of conveying the product downstream relative to the machine).

[0008] The spacers are inserted into the stack through circumferential grooves on the side surfaces of the folding rollers, the number and arrangement of the circumferential grooves corresponding to the number and arrangement of the fingers of the spacers, so that the spacers can be inserted into the radial thickness of the folding rollers (and therefore upstream of the radial outer periphery of the folding rollers).

[0009] Thus, by means of the spacers, the stack of napkins can be compressed immediately downstream of the release from the folding drum, thereby avoiding the complicated disengagement mechanisms provided by the solutions according to the prior art.

[0010] According to aspects of the present invention, the foregoing and other objects and advantages are achieved by a machine and process for folding, cutting and stacking napkins. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The functional and structural features of some preferred embodiments of the machine and process according to the present invention will now be described. With reference to the accompanying drawings, in which:

[0012] - Figures 1 to 4 is a schematic perspective view of various components of a machine according to one embodiment of the present invention, showing in sequence a pair of folding rollers, a pair of spacers, a blade, a storage platform for napkins cut downstream of the spacers, and a pair of slides suitable for receiving napkins from the aforementioned platforms; and

[0013] - Figures 5A to 16B Schematic front and top views, respectively, of a machine depicted in an operating sequence of a method for folding, cutting and stacking napkins according to one embodiment of the invention. DETAILED DESCRIPTION

[0014] Before describing various embodiments of the present invention in detail, it should be clarified that the application of the present invention is not limited to the structural details and configurations of components set forth in the following description or illustrated in the accompanying drawings. The present invention may have other embodiments and be implemented or constructed in various ways in practice. It should also be understood that the phrases and terms used herein are for descriptive purposes only and should not be construed as limiting.

[0015] With reference to the example of the accompanying drawings, a machine 9 for folding, cutting and stacking napkins comprises: a feed station 10 including means configured to convey at least one continuous sheet 12 of material for making a plurality of napkins 13 downstream of said feed station 10; and at least one pair of folding drums or rollers 14 arranged downstream of the feed station 10 and adapted to be fed with said continuous sheet 12.

[0016] The folding drums 14 are rotatable about axes of rotation which are parallel to one another and which, in use, are arranged in the horizontal direction, and are configured to push the continuous web 12 so as to arrange it in a plurality of overlapping zigzag layers, the dimension of which, in a horizontal direction perpendicular to the axis of the folding drums 14, is at least equal to the width of two juxtaposed napkins 13. The overlapping direction of the continuous web layers 12 defines the feed direction of the folding and stacking cycle of the machine 9 (the feed direction being a substantially vertical direction in the operating state of the machine).

[0017] The machine 9 further comprises a blade 16 arranged downstream of the folding drum 14, parallel to the axis of said folding drum, in a position intermediate between the axes of said folding drum 14, said blade 16 being suitable for centrally cutting the overlapping layers of said continuous sheet 12 fed by the folding drum 14 so as to form two identical napkins 13 from each layer.

[0018] A pair of spacers 18 is also provided, which are movable in a direction parallel to the feed direction and in a direction parallel to the axis of the folding drum 14, and the spacers 18 are arranged symmetrically with respect to the blade 16 and have fingers 20 extending in a direction parallel to the axis of the folding drum 14, the fingers 20 being configured to stably support the napkin 13 downstream of the blade 16 relative to a horizontal plane perpendicular to the feed direction and / or to compress the napkin 13 upstream of the blade 16 in the direction of the blade.

[0019] According to a preferred embodiment, the fingers 20 are spaced apart from each other in a horizontal direction parallel to the axis of the folding drum 14 .

[0020] According to one embodiment, the machine 9 comprises a platform 22 having a support surface, situated in a horizontal plane perpendicular to the feed direction and suitable for receiving the napkins 13 from the fingers 20 of the spacers 18 , said platform 22 being movable in the feed direction.

[0021] The platform 22 can be configured to support stacks of continuous sheet layers 12 (which are formed downstream of the folding rollers 14) to carry them downstream of the blade 16; when the stacks reach a predetermined thickness (in the feed direction), the pairs of spacers 18 are configured to be inserted into the stacks being formed near the folding rollers 14 to support the overlying portion of the stack being formed while the platform 22 carries the first portion of the stack downstream (e.g., Figures 5A to 11B ).

[0022] When the stack supported by the spacers 18 also reaches a predetermined thickness (in the feed direction), the spacers 18 are configured to arrange the stack on the platform 22 and then raise and insert them into the stack being formed near the folding rollers 14 to support the overlying portion of the stack being formed while the platform 22 transports the first portion of the stack downstream (such as Figures 12A to 16B shown in ).

[0023] The platform 22 can be configured to allow the spacer 18 to penetrate each other between the platform 22 and the finger-shaped members 20 in the feed direction (for example, by sequentially presenting the fingers 20 spaced apart from each other and offset relative to the spacer 18 so that the spacer can be inserted into the space between the fingers of the platform 22 so as to be able to penetrate its supporting surface).

[0024] In this way (such as Figures 12A to 16B When the stack of continuous sheet layers 12 has reached a predetermined thickness downstream of the folding rollers 14 (corresponding, for example, to the thickness of a napkin packaging unit), pairs of spacers 18 support the descent of said stack until it is deposited on a platform 22 (penetrating its support surface, the fingers of the spacers holding the napkins), which in turn takes over the stack and conveys it downstream of the machine.

[0025] As an alternative to the platform 22 or in combination with the platform, a second pair of spacers 18 can be provided, so that the first pair of spacers supports the descent of the stack being formed downstream of the folding rollers 14, and, when the stack has reached a predetermined thickness (in the feed direction), the second pair of spacers 18 is inserted into the stack being formed near the folding rollers 14 to support the overlying part of the stack being formed, while the first pair of spacers 18 transports the first part of the stack downstream.

[0026] The folding rollers 14 have, on their side surfaces, circumferential grooves 15, the number and arrangement of which correspond to the number and arrangement of the teeth 20 of the spacers 18, said circumferential grooves 15 being suitable for allowing the insertion of said teeth 20 into the radial thickness of the folding rollers 14. In this way, the insertion of the pairs of spacers 18 into the stack being formed is facilitated by isolating a portion of said spacers situated downstream (the portion taken over by the platform 22 or the additional pair of spacers 18) from the portion of the adjacent folding rollers 14 being formed.

[0027] A pair of horizontal slides 24 may also be provided, symmetrically arranged relative to the blades 16 and movable in a direction parallel to the axis of the folding drum 14, said slides 24 being suitable for receiving the napkins 13 from the fingers 20 of the spacer 18 or from the platform 22. Conveniently, said slides 24 may be equipped with a conveyor belt suitable for moving the napkins 13 in a direction parallel to the axis of the folding drum 14, thereby removing the napkins from the machine (e.g. Figure 4 and Figure 16B shown).

[0028] Conveniently, the continuous sheet material 12 from which the plurality of napkins 13 may be made may be a cellulose-based material (eg, when the machine is configured to make conventional paper napkins).

[0029] According to another aspect of the invention, a process for folding, cutting and stacking napkins comprises the following steps: providing a machine 9 according to any of the embodiments described above; feeding a continuous sheet 12 of material for making a plurality of napkins 13 to a folding drum 14; moving a spacer 18 in a direction parallel to the axis of the folding drum 14 (and therefore perpendicular to the feed direction of the napkins) so that corresponding fingers 20 fit into corresponding circumferential grooves 15 of the folding drum 14 arranged below (i.e., downstream of) the drum; moving the continuous sheet 12 in a zigzag pattern perpendicular to the feed direction by means of the folding drum 14 so as to form a stack of overlapping layers along the feed direction, the layers having a dimension in a horizontal direction perpendicular to the axis of the folding drum 14 that is at least equal to the width of two juxtaposed napkins 13, the layers being collected by the fingers 20; moving the spacer 18 in a direction parallel to the feed direction until at least a portion of the overlapping layers of the continuous sheet 12 pass through the blade 16; and removing the napkins 13 from the spacer 18.

[0030] Furthermore, in the present description and claims, terms and expressions referring to position and orientation such as "longitudinal", "transverse", "vertical" or "horizontal" refer to the orientation of the stack of layers of sheet material downstream of the folding rollers.

[0031] Various aspects and embodiments of the machine and process according to the present invention have been described. It should be understood that each embodiment can be combined with any other embodiment. Furthermore, the present invention is not limited to the embodiments described, but can be varied within the scope defined by the claims.

Claims

1. A machine (9) for folding, cutting and stacking napkins, comprising: - a feeding station (10) comprising means configured for conveying downstream of said feeding station (10) at least one continuous sheet (12) of material for manufacturing a plurality of napkins (13); - at least one pair of folding rollers (14) arranged downstream of the feed station (10) and adapted to be fed with the continuous web (12), the folding rollers (14) being rotatable about rotation axes parallel to one another and arranged in the horizontal direction when in use, the folding rollers (14) being configured to push the continuous web (12) so that it is arranged in a plurality of superimposed zigzag layers, the dimensions of the layers in a horizontal direction perpendicular to the axes of the folding rollers (14) being at least equal to the width of two juxtaposed napkins (13), the overlapping direction of the layers of the continuous web (12) defining the feed direction of the folding and stacking cycle of the machine (9); - a blade (16) arranged downstream of the folding drum (14) parallel to the axis of the folding drum (14) in a central position relative to the interaxial spacing between the folding drums (14), the blade (16) being suitable for centrally cutting the overlapping layers of the continuous sheet (12) fed by the folding drum (14) so ​​that two identical napkins (13) are formed from each layer; and - a pair of spacers (18) movable in a direction parallel to the feed direction and in a direction parallel to the axis of the folding rollers (14), the spacers (18) being arranged symmetrically with respect to the blades (16) and having fingers (20) extending in a direction parallel to the axis distance between the folding rollers (14), the fingers (20) being configured to stably support the napkin (13) downstream of the blades (16) relative to a horizontal plane perpendicular to the feed direction and / or to compress the napkin (13) in the direction of the blades (16) upstream of the blades (16); The folding drum (14) has circumferential grooves (15) on its side surface, the number and arrangement of the circumferential grooves corresponding to the number and arrangement of the teeth of the spacer (18), and the circumferential grooves (15) are suitable for allowing the teeth to be inserted into the radial thickness of the folding drum (14).

2. The machine according to claim 1, wherein The fingers (20) are spaced apart from each other in a horizontal direction parallel to the axis of the folding drum (14).

3. Machine according to claim 1 or 2, comprising a platform (22) with a supporting surface, said platform being situated in a horizontal plane perpendicular to said feed direction and being adapted to receive said napkins (13) from said fingers (20) of said spacers (18), said platform (22) being movable along said feed direction.

4. The machine according to claim 3, wherein: The platform (22) is configured to allow mutual penetration between the platform (22) and the fingers (20) of the spacer (18) in the feed direction.

5. The machine according to claim 3, comprising a pair of horizontal slides (24) arranged symmetrically with respect to the blade (16) and movable in a direction parallel to the axis of the folding drum (14), the slides (24) being suitable for receiving the napkins (13) from the fingers (20) of the spacer (18) or from the platform (22).

6. The machine according to claim 1 or 2, wherein: The material of the continuous sheet (12) used to make the plurality of napkins (13) is a cellulose-based material.

7. A process for folding, cutting and stacking napkins, comprising the steps of: a) Providing a machine (9) according to any one of claims 3 to 5; b) feeding a continuous sheet (12) of material for manufacturing a plurality of napkins (13) to the folding drum (14); c) moving the spacer (18) in a direction parallel to the axis of the folding roller (14) so ​​that the corresponding finger-shaped member (20) is arranged below the corresponding folding roller (14); d) moving the continuous sheet (12) in a zigzag direction perpendicular to the feed direction by means of the folding drum (14), thereby forming a stack of overlapping layers along the feed direction, the layers having a dimension in a horizontal direction perpendicular to the axis of the folding drum (14) at least equal to the width of two juxtaposed napkins (13), the layers being collected by the fingers (20); e) moving the spacer (18) in a direction parallel to the feed direction until at least a portion of the overlapping layers of the continuous sheet (12) passes the blade (16); f) Removing the napkin (13) from the spacer (18).

8. The process according to claim 7, wherein Step c) is preceded by collecting a stack of overlapping layers of the continuous sheet (12) from the folding drum (14) on the platform (22) and moving the platform (22) in a direction parallel to the feed direction until at least a portion of the overlapping layers of the continuous sheet (12) passes the blade (16).

9. The process according to claim 7, wherein Step f) is performed by transferring the napkin (13) from the spacer (18) to the platform (22).

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