STRUCTURE OF INTERFOLDING MACHINE

Abstract

An interfolding machine of sheet material for making a stack of interfolded sheets (1) comprising at least one web (2) of material to interfold that is cut (3) into sheets (4a,4b,4c, 4d,4e,4f,4g) of predetermined length and partial overlapping means (5,6) for the sheets (4c,4d,4e,4f,4g) in order to form an overlapped portion (7) between two consecutive sheets. Interfolding means are provided (8,9) adapted to produce the stack (1) and conveying means (10) interfolding means are provided adapted to convey the partially overlapped sheets (4d,4e,4f) in a zone set between the means for partially overlapping (6) and the interfolding means (8,9). are furthermore, means are provided for keeping the overlapping fraction of the sheets unchanged (4d,4e,4f), through a plurality of belts (11) and a plurality of fixed guides (12) facing the belts (11) so that between the belts (11) and the respective guides (12) a channel is formed (13) for conveying the partially overlapped sheets (4d,4e,4f). The belts (11) have a plurality of teeth (14) oriented towards the guides (12) and distanced from each other such that least at one tooth (14) coincides with a respective overlapped portion (7), pushing the overlapped portion (7) against respective guides (12), so that the conveying means can convey the sheets (4d,4e,4f) partially overlapped along the channel (13) preventing the overlapping fraction of the sheets from changing (4d,4e,4f).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristic and the advantages of the interfolding machine, according to the invention, will be made clearer with the following description of an exemplary embodiment thereof, exemplifying but not limitative, with reference to the attached drawings, in which like reference characters designate the same or similar parts, throughout the figures of which:

FIG. 1 shows a cross sectional diagrammatical view of an interfolding machine, according to the invention;

FIG. 2 shows a cross sectional view of the conveying means of the partially overlapped sheets between a overlapping roller and the interfolding rollers;

FIG. 3 shows a cross sectional view of the conveying means that is similar to FIG. 2 but without the presence of the sheets.

Claims

1. Interfolding machine of sheet material for making a stack of interfolded sheets (1) comprising: at least one web (2) of material to interfold that is cut (3) into sheets (4a,4b,4c, 4d,4e,4f,4g) of predetermined length;means for partially overlapping (5,6) said sheets (4c,4d,4e,4f,4g) in order to form an overlapped portion (7) between two consecutive sheets, wherein said overlapped portion is a predetermined fraction of said sheet length;interfolding means (8,9) adapted to make said stack (1);conveying means (10) adapted to convey said partially overlapped sheets (4d,4e,4f) in a zone set between said means for partially overlapping (6) and said interfolding means (8,9),

2. Interfolding machine, according to claim 1, wherein said conveying means (10) comprise a couple of conveying rollers (15) arranged along said channel, whereby at an overlapping zone (7) in said channel (13) upstream from said conveying rollers (15), where the only downstream sheet (4e) is pulled by said conveying rollers (15), and the overlapping fraction of said sheets (4d,4e) remains unchanged owing to the pressure of said upstream sheet (4d) against said downstream sheet (4e) and against said guides by said tooth (11), so that the upstream sheet is kept pressed against said downstream sheet at said overlapping zone, obtaining a conveying contribution.

3. Interfolding machine, according to claim 1, wherein between said guides (12) are provided rotatable support rollers (15) on said sheets (4d,4e,4f) are provided, said rollers (15) having their boundary that protrudes in said channel (13) and have a peripheral speed equal to said belts (11).

4. Interfolding machine, according to claim 1, wherein said means for overlapping provide an overlapping roller (6) and a transfer roller (5), said transfer roller (5) rotating at a speed higher than said overlapping roller (6) in order to deposit on said overlapping roller (6) the sheets (4c,4d) overlapped according to said fraction.

5. Interfolding machine, according to claim 4, wherein said fraction is ⅓ of said sheet length, so that a stack (1) is obtained of Z interfolded sheets.

6. Interfolding machine, according to claim 4, wherein said overlapping roller (5) provides a plurality of grooves (18) where said belts are present (11).

7. Interfolding machine, according to claim 1, wherein said belts (11) run parallel to said guides up to a point as close as possible to said interfolding means (8,9), at said point means being provided for deviating (16) said belts (11), whereby said overlapped portions (7) are kept together by the same speed of said teeth (14) up to said point.

8. Interfolding machine, according to claim 1, wherein driving means are provided for said belts, so that said belts have a peripheral speed substantially the same as said overlapping roller (5).