A METHOD AND A UNIT FOR FOLDING SANITARY PADS

Technical Field

The present invention relates to a method and a unit for folding sanitary pads.

In particular, albeit with no limitation implied, one application of the present invention would be that of folding light incontinence pads for use by women.

Background Art Familiar sanitary pads of the aforementioned type present a substantially rectangular outline and comprise two sheets, one impermeable, the other permeable, between which a core of absorbent material is sandwiched.

Around the outer edge of the assembled sanitary pad, the two sheets are matched and joined to create a peripheral seam of predetermined width.

The two longitudinal edges of the seam present an elasticated segment coinciding with a substantially central area of the pad.

Conventionally, machines used to manufacture sanitary pads of the type in question incorporate a unit by which each pad is bent along two fold lines, disposed transversely to its longitudinal axis, in such a way as to form three parts identifiable respectively as a front portion, a central portion and a rear portion of the pad.

Folded thus into three superposed portions, the sanitary pads are then packaged singly or in multiples through the agency of a further unit forming part of the manufacturing machine.

Likewise conventionally, sanitary pads of the type in question need to be anatomically contoured.

This means in practice that when removed from the packaging, the pads should present a substantially cupped appearance with the inside face of the rear portion angled toward the central and front portions, and with the aforementioned elasticated portions converging toward one another, likewise from the inside face of the pad.

The anatomical contours described above are not easily produced with conventional folding units.

In existing machines, during the course of the successive steps whereby the sanitary pad is folded into three portions, the aforementioned longitudinal edges tend in practice to lie flat in the same plane as the central portion, and to remain in this position permanently thereafter. Consequently, when the pad is opened out by the user, it appears substantially flat, or in any event with an anatomically contoured shape that is less than satisfactory.

Disclosure of the Invention

The object of the present invention is to provide a method and a unit for folding sanitary pads of the type described above, such as will ensure that the aforementioned anatomical contours are retained by the pads following the folding operation and at the moment of use by the wearer.

The stated objects are realized in a method and a unit for folding sanitary pads, of which the essential features are as recited in the respective claims appended.

Brief Description of the Drawings

The invention will now be described in detail, by way of example, with the aid of the accompanying drawings, in which:

- figure 1 is a schematic front elevation view of a unit for folding sanitary pads in accordance with the present invention;

- figures 2 and 3 are perspective views of a sanitary pad foldable by the unit of figure 1 , seen in two different configurations;

- figures 4, 5 and 6 are perspective views illustrating details of the folding unit in figure 1 during successive operating steps; - figure 7 is a perspective view showing a detail of the folding unit in figure 1 in an alternative embodiment;

- figures 8 and 9 show a detail of figure 4 in two further alternative embodiments.

Detailed Description of the Preferred Embodiments Referring to figure 1, numeral 1 denotes a machine for manufacturing sanitary pads, comprising a unit 2 by which the pads 3 are folded, The folding unit 2 is carried by a vertical bulkhead 4.

Also forming part of the machine 1 are a feed unit 5, and a wrapping unit shown schematically as a block denoted 6, between which the folding unit 2 is interposed.

The pads 3 are sanitary pads, and in particular, light incontinence pads for women.

With reference also to figures 2 and 3, the sanitary pads 3 present a substantially rectangular outline, aligned on a longitudinal axis A, and comprise a central absorbent core 7 sandwiched between a sheet of impermeable material (such as polyethylene), providing the outside face 8 of the pad 3, and a sheet of permeable material (such as nonwoven fabric) providing the inside face 9 of the pad 3.

The two sheets are sealed directly to one another around the outer edge of the sanitary pad 3, in such a way as to create a peripheral seam 10 of predetermined width.

As will become clear in the course of the specification, the sanitary pad 3 is bent by the folding unit 2 along fold lines 11 and 12 transverse to the longitudinal axis A, in such a way as to create thi'ee portions of substantially identical longitudinal dimensions, referred to respectively hereinafter as a rear portion or first end portion 13, a central portion 14, and a front portion or second end portion 15 of the pad 3.

The two longitudinal parts of the seam 10, coinciding at least with the central portion 14, each present an elasticated segment 16. The elasticated segments 16 are included in order to ensure that when the pad 3 is removed from its packaging, it will assume an anatomically contoured appearance as illustrated in figure 3.

At the same time, the elasticated segments 16 ensure that when the pack is opened, the corresponding parts of the seam 10 remain angled toward one another on the side of the inside face 9.

The folding unit 2 comprises an aspirating conveyor 17 on which each pad advances in a direction parallel with its longitudinal axis A.

The conveyor 17 is embodied as a drum set in rotation continuously by drive means (not illustrated), in the direction of the arrow denoted F, about a horizontal axis 18 extending at right angles to the bulkhead 4.

Numeral 19 denotes an infeed station at which the sanitary pads 3 are released to the drum by an aspirating conveying roller 20 forming part of the feed unit 5, and numeral 21 denotes an outfeed station at which the pads 3 are released by the drum to the wrapping unit 6.

The pads 3 are directed by the feed unit 5 toward the infeed station 19 with their respective inside faces 9 directed toward the roller 20. Thus, each pad 3 is released to the drum 17 with the respective outside face 8 directed toward the surface of the selfsame drum 17.

In an alternative solution (not illustrated), the pads 3 could be directed by the feed unit 5 toward the infeed station 19 with their respective outside faces 8 directed toward the roller 20. In this instance, the feed unit will include an intermediate transfer conveyor by which the pads 3 are released to the drum 17 with the respective outside faces 8 directed toward the surface of the drum 17.

Referring also to figure 4, the outer cylindrical surface of the drum 17 presents a plurality of angularly equispaced aspirating pockets 22, each accommodating a single sanitary pad 3 placed with its axis A transverse to the axis 18 of the drum 17 and with the rear portion 13 trailing the other portions, considered relative to the direction of rotation F of the drum 17. Each pocket 22 presents a base 23 having a transverse dimension marginally greater than the transverse dimension of the absorbent core 7, and is delimited laterally by raised side walls 24 converging from the outermost edges of the pocket toward the base 23.

Both the base 23 and the side walls 24 of the pocket 22 present holes 25 connected to a source of suction (not illustrated).

Associated with each pocket 22, at a point coinciding with the position occupied by the central portion 14, is a lateral folding mechanism 26 comprising two fork elements 27a and 27b arranged symmetrically in relation to the pocket 22.

Each fork element 27a and 27b is equipped with a first prong 28 and a second prong 29, disposed parallel to the axis 18 of the drum and spaced apart by a distance substantially equal to the distance between the two fold lines 11 and 12; the two pairs of prongs are aligned one with another.

Each fork element 27a and 27b is capable of reciprocating motion in a direction transverse to the pocket 22, induced by actuator means 30, through slots 24a in the side walls 24, between a position of disengagement from the pocket 22, and an active position internally of the selfsame pocket in which the tips presented by the two prongs 28 and 29 of the one fork element 27a and the corresponding tips presented by the two prongs 28 and 29 of the other fork element 27b are brought closer together.

Referring to figure 5, the unit 2 further comprises a folding mechanism 31 associated with each pocket 22 at the upstream end, which is pivotable about an axis 32 parallel to the axis 18 of the drum and movable thus between a position of disengagement from the pocket 22, and a position of engagement with the rear portion 13 of the sanitary pad 3, internally of the pocket 22.

The folding mechanism 31 comprises two rods 33 arranged symmetrically relative to the pocket 22, parallel to the axis 18 of the drum, aligned coaxially one with another and mounted to the ends of respective arms 34 disposed mutually parallel and pivotable about the aforementioned axis 32. The two arms 34 are caused by first actuator means 36 to move synchronously toward and away from one another relative to the pocket 22, and caused by second actuator means 37 to rotate about the common axis 32 in such a way that the first portion 13 of the pad can be folded by the two rods 33. Also associated with the drum 17, at a position denoted 38 , is a cylinder 39 set in rotation continuously about an axis 40 parallel to the axis 18 of the drum. The cylinder 39 and the drum 17 rotate in opposite directions.

The revolving surface of the cylinder 39 is furnished with holes (not illustrated) connected to a source of suction, and combines with the surface of the drum 17 to create a passage 42 of which the height is marginally less than twice the thickness of the sanitary pad 3.

Referring also to figure 6 ₅ the unit 2 comprises a restraint 43 located downstream of the cylinder 39, presenting a curved end portion 44 positioned facing the drum 17 and combining with the surface of the selfsame drum to create a channel 45 of height marginally less than triple the thickness of the sanitary pad 3.

In operation, the sanitary pads 3 arrive at the infeed station 19 and are released in succession by the conveying roller 20 to the drum 17, which is set in rotation continuously.

Each pad 3 is taken up in a respective pocket 22 with its outside face 8 offered in contact to the base 23 and the longitudinal segments of the peripheral seam 10 in contact with the convergent side walls 24.

At a station denoted 46, located immediately downstream of the infeed station 19, the two fork elements 27a and 27b of the lateral folding mechanism 26 associated with the pocket 22 move inwards on either side of the sanitary pad 3, in such a way as to engage and flatten the two elasticated segments 16 coinciding with the central portion 14.

In this situation, the two pairs of prongs 28 and 29 combine respectively to establish the aforementioned lines 11 e 12, internally of the pocket 22, along which the pad 3 will be folded. Rather than the reciprocating motion aforementioned, in another possible embodiment the fork elements 27a and 27b might be rendered pivotable about axes disposed transversely to the respective prongs 28 and 29, in such a way that the two elasticated segments 16 can be flattened by a simple angular movement, without the prongs 28 and 29 sliding on the seam 10.

At a further station 47 downstream of the first folding station 46, the two rods 33 of the folding mechanism 31 slide axially through respective slots 48 into the pocket 22 and locate behind the rear portion 13.

On reaching the travel limit of the movement induced by the first actuator means 36, the two rods 33 are caused to rotate about the common axis 32 by the second actuator means 37, in such a way as to fold and flatten the rear portion 13 of the pad over the central portion 14, which continues to be retained by the lateral folding mechanism 26.

From the foregoing, it will be evident that the fork elements 27a and 27b perform the dual function of seam-folding means by which the elasticated segments 16 associated with the central portion 14 are flattened and retained, and of reaction means operating in conjunction with the folding mechanism denoted 31.

Besides ensuring that the rear portion 13 will be bent exactly along the fold line 11, the action of the fork elements 27a and 27b also serves to hold the elasticated segments 16 flattened against the central portion 14 of the pad during the folding operation in question.

Downstream of the folding station 47 and approaching the entry to the passage 42, at the position denoted 38, the combined action of the drum 17 and the aspirating cylinder 39 is instrumental initially in bending the front portion 15 of the sanitary 3 around the relative prongs 29, whereupon the front portion 15 is detached from the cylinder 39, the pad 3 enters the channel 45, and the front portion 15 is flattened over the rear portion 13, so that the three folded portions 13, 14 and 15 of the pad 3 are mutually superposed.

Accordingly, the front portion 15 is folded by relative folding means composed of the aspirating cylinder 39 and the restraint 43.

Moving along the channel 45, the fork elements 27a and 27b are caused to return to the position of disengagement, drawing clear of the pads 3, and the pads 3 advance to the outfeed end of the channel 45, ultimately reaching the entry point of the wrapping unit 6.

In the example of figure 7, the two fork elements 27a and 27 of the lateral seam-folding means 26 are replaced by single rods arranged in two pairs 49a and 49b, the upstream rods denoted 50, the downstream rods 51.

The rods 50 and 51 of each pair are disposed mutually parallel and in the same plane, the rods 50 and 51 of the one pair 49a aligned respectively with the rods 50 and 51 of the other pair 49b.

Also, the two pairs of rods 50 and 51 are coupled to respective motion- inducing means consisting in actuators 52 and 53 operating independently of one another.

The two pairs of rods 50 and 51 are deployed simultaneously by the actuators 52 and 53 to fold the respective segments 16 of the seam, whereas the movements by which the rods are retracted and disengaged from the respective fold lines 11 and 12 are induced sequentially. More exactly, the first two rods 50 are retracted once the rear portion 13 has been folded, and the second two rods 51 are retracted after the front portion 15 has been folded.

Self-evidently, in effect, once the rear portion 13 has been folded, there is no longer any need for the seam-folding and reaction means to remain in position on the corresponding fold line 11.

In an alternative solution, the movements by which the rods 50 and 51 are deployed to fold the segments 16, and the movements by which the rods are retracted and disengaged from the respective fold lines 11 and 12, could both be induced sequentially by the actuators 52 and 53.

More exactly, the first rods 50 and the second rods 51 would be operated by the actuators 52 and 53 in such a manner that the deployment of the second rods 51 occurs after the deployment of the first rods 50, and the retraction of the second rods 51 occurs after the retraction of the first rods 50.

In another possible embodiment, illustrated in figure 8, the folding mechanism 31 associated with each pocket 22 consists in an arm 54 bent to a right angle, anchored hingedly at one end and pivotable thus on an axis 55 parallel to the axis 18 of the drum. The arm 54 is capable of angular movement alternating between an at-rest position internally of the drum 17, and an operating position in which the first end portion 13 of the pad is engaged and folded over the central portion 14.

In a further embodiment, illustrated in figure 9, the folding mechanism 31 associated with each pocket 22 comprises a flat element 56 capable of reciprocating movement within a plane substantially tangential to the cylindrical surface of the drum 17, in such a way as to flatten the first end portion 13 over the central portion 14 during its forward stroke.

The method of folding sanitary pads according to the present invention will be readily discernible from the foregoing description.

In particular, the method disclosed includes a step of conveying successive pads 3 along the direction of the longitudinal axis A, in the pockets 22 of an aspirating conveyor 17; a step of folding each pad 3 on a first fold line 11 and a second fold line 12, both of which lying transverse to the longitudinal axis A, through the agency of folding means, wherein the folding step includes a first subsidiary step of folding a first end portion 13 of the pad 3 along the first fold line 11 over a central portion 14 of the pad 3, and a second subsidiary step of folding a second end portion 15 of the pad 3 along the second fold line over the first end portion 13.

The aforementioned folding step is preceded by a step in which segments 16 of the seam 10 located between the first and second fold lines 11 and 12 are turned in and flattened over the central portion 14 through the agency of seam- folding means 26, and a step in which the segments 16 are retained against the central portion 14 by the selfsame seam-folding means 26.

The folding step includes a step of establishing the first and second fold lines 11 and 12 through the agency of the seam-folding means 26.

The first subsidiary folding step consists in doubling the trailing or upstream end portion 13, considered relative to the conveying direction, over the central portion 14, and the second subsidiary folding step consists in doubling the leading or downstream end portion 15 over the rear portion 13.

The step of retaining the flattened segments 16 by way of the seam-folding means 26 terminates with the completion of the second subsidiary folding step.

Alternatively, the step of retaining the segments 16 by way of the seam- folding means 26 terminates, in the case of the first fold line 11, on completion of the first subsidiary folding step, and in the case of the second fold line 12, on completion of the second subsidiary folding step.

The method and the unit described above with reference to sanitary pads of the type illustrated are applicable similarly in the case of "lady" type pads, that is to say without the elasticated segments.

In this instance, when the parts of the seam associated with the central portion are flattened, the overall dimensions presented by packs of such pads can be reduced. In other words, the packs can be made more compact.