Patent Description:
Lines for the production of nappies, and in particular, of nappy pants, are made up of a multitude of operating stations and units which, starting from the raw materials, continuously perform successive and/or parallel processes to obtain finished products that are suitably positioned, folded and ready for packaging.

With reference to <FIG>, it may be observed that a pair of nappy pants, once formed, can be schematized as two rectangles, orthogonal to each other and at least partly intersecting.

The nappy has, amongst others, four characteristic dimensions A, B, C and D which are respectively, with reference to <FIG>, the width of the elastic bands in the waist, the height of the elastic bands in the waist, the length of the absorbent pad and the width of the absorbent pad; in the product, the absorbent pad is obviously two times C in length because, in the illustration, the pad is folded in half.

The processing units of the production line are each structured to handle the product and the semi-products which, as they advance along the line, progressively form the end product.

In particular, each processing unit must be configured to adapt to at least one of the above mentioned four dimensions A, B, C and D for each nappy size being produced.

When the size of the nappy or of one of its components has to be changed, hence when at least one of those dimensions changes, the processing units must generally be adjusted or modified to be able to handle the dimensions of the new size.

More precisely, it is necessary to make macro-adaptations or macro-adjustments, together with micro-adaptations or micro-adjustments affecting minor aspects of the line.

By way of non-limiting example, the following macro-adjustments may be necessary: replacing the absorbent pad cutting unit as a function of the dimension C of the pads; replacing the absorbent pad stepper positioning unit when the dimension A of the elastic bands changes; replacing the cutting means or varying the diameter of the cutting means based on cutting and shaping requirements as a function of A, B and C; replacing the label applicator or varying its diameter as a function of A; replacing, or changing the diameter of the welding unit for welding the elastic bands in the waist based on dimension A; modifying or replacing the product orienting and spacing units based on dimensions A, B, C.

In addition to all these and other adjustments that must be carried out on the line when product size changes, the Applicant has noticed that prior art lines are unable to continuously cover all the possible sizes, from the smallest to the largest, but only some of the sizes in the range from the smallest to the largest, based on design choices.

The Applicant has thus observed that in the relevant technical sector, there remains a need for a line for the production of nappies, and in particular, of nappy pants, capable of making products, as required, in any size after just some quick and relatively simple adjustments.

In this context, our intention is to propose a line and a process for the production of nappy pants capable of overcoming at least some of the drawbacks of the prior art and of meeting the above mentioned need.

One aim of this invention is to provide a line and a process for the production of nappy pants to allow making any product size, even to meet market demand for increasingly customized products.

One aim of this invention is to provide a line for the production of nappy pants to allow adapting the line in a practical manner (for example, automated or by replacing and/or adjusting at least one mechanical part) to make the product in any size, at least as regards the macro-adjustments necessary for size changeover.

These aims are achieved by a line and a process for the production of nappy pants comprising the technical features described in one or more of the accompanying claims. The dependent claims correspond to possible different embodiments of the invention. Documents <CIT> and <CIT> disclose prior art related to the present technical field.

According to an aspect, this disclosure regards a line for the production of nappy pants of the type each comprising at least one absorbent pad and a plurality of elastic bands.

Once assembled, the elastic bands and the absorbent pads form the pants structure that identifies the type of product concerned.

The production line comprises a forming unit for forming a composite web from which the absorbent pads are obtained. The composite web is for example made up of a topsheet, a backsheet and an absorbent structure sandwiched between the two.

The production line comprises an elastic band forming unit for forming the elastic bands.

The production line comprises an assembly line which has an infeed for a composite web, an infeed for elastic bands and an outfeed for the nappy pants produced.

According to an aspect of the disclosure, the assembly line comprises a plurality of processing units to construct the nappy pants from at least one composite web and elastic bands.

According to an aspect, the processing units each comprise a computerised command and control unit and the production line comprises a computerised high level control unit in communication with the computerised command and control units of the processing units.

According to an aspect, each processing unit is provided with a respective computerised command and control unit and all the computerised command and control units are controlled, directly or indirectly, by the high level control unit.

According to an aspect, the high level control unit is configured to impart at least one respective control signal to each computerised command and control unit.

According to an aspect, each control signal is a function of the size of the nappy pants being produced in the production line.

The processing units are each configured to perform a respective step of processing as a function of the size set using the respective control signal.

Advantageously, the production line is able to make nappy pants of any size of all the possible sizes and adapting the processing unit to a different size is automated on the basis of the commands imparted by a single high level control unit which sends the control signals to each single processing unit.

The control signals are a function of the size, and each processing unit adapts to the new size thanks to its own local command and control unit.

According to an aspect, at least one control signal generated by the high level control unit is a function of the width of the absorbent pad.

According to an aspect, at least one control signal generated by the high level control unit is a function of the length of the absorbent pad.

According to an aspect, at least one control signal generated by the high level control unit is a function of the width of an elastic band in the waist of the nappy pants.

According to an aspect, at least one control signal generated by the high level control unit is a function of the height of an elastic band in the waist of the nappy pants.

According to an aspect, the production line comprises a processing unit which comprises a cutting device for cutting the composite web to obtain a succession of absorbent pads. The cutting device preferably comprises at least one cutter driven by the computerised command and control unit of the processing unit.

Preferably, the cutter is actuated according to an electronic cam profile based on a control signal.

The control signal is generated by the high level control unit as a function of the length of the absorbent pad. The electronic cam profile, that is an electronic cam drive of the cutter, allows meeting all requirements regarding size, since it can cut the web into pieces of any length.

According to an aspect, the production line comprises a processing unit that comprises a turning and spacing device to space and turn the absorbent pads of a succession of absorbent pads.

According to an aspect, the turning and spacing device comprises at least one rotary pickup means for picking up an absorbent pad and a movement system for moving the pickup means.

The movement system is driven by the computerised command and control unit of the processing unit and is actuated according to an electronic cam profile based on a control signal received from the processing unit.

The control signal is generated by the high level control unit as a function of the width of an elastic band in the waist of the nappy pants. The processing unit can thus advantageously adapt to any size of absorbent pad, picking it up at one spacing and depositing it at another.

According to an aspect, the production line may comprise a single processing unit that not only cuts the composite web but also spaces, repositions and orients the absorbent pads.

According to an aspect, the movement system may comprise at least one linear motor.

According to an aspect, the production line comprises a processing unit that comprises a cutting device to at least partly cut the elastic bands in a coupling zone where the elastic bands are coupled to a corresponding absorbent pad.

According to an aspect, the cutting device comprises at least one cutter driven by the computerised command and control unit of the processing unit.

According to an aspect, the cutter is actuated according to an electronic cam profile based on a respective control signal.

The control signal is generated by the high level control unit as a function of the width of an elastic band in the waist of the nappy pants and/or of the width of the absorbent pad.

Advantageously, the cutter, being actuated by an electronic cam, can execute any command from the high level control unit, based on the size of the nappy pants.

According to an aspect, the production line comprises a processing unit that comprises a cutting device for at least partly shaping the elastic bands, for example, at the joining zone where the absorbent pad and the elastic bands of the nappy pants are joined.

According to an aspect, the cutting device is a laser or waterjet cutting device and is driven by the computerised command and control unit of the processing unit based on a control signal generated by the high level control unit as a function of the length of the absorbent pad and/or as a function of the width of an elastic band in the waist of the nappy pants and/or as a function of the height of the elastic band in the waist of the nappy pants.

According to an aspect, the production line comprises a processing unit that comprises an applicator which applies a label to each pair of nappy pants.

According to an aspect, the applicator is driven according to an electronic cam profile based on a control signal.

The control signal is generated by the high level control unit as a function of the width of an elastic band in the waist of the nappy pants. Advantageously, the applicator, being actuated by an electronic cam, can execute any command from the high level control unit, based on the size of the nappy pants so that the label is positioned correctly according to the size.

According to an aspect, the production line comprises a processing unit that comprises a welding device for welding the elastic bands in the waist of the nappy pants.

According to an aspect, the welding device comprises a plurality of welding units which are spaced along the feed path of the nappy pants to be formed as a function of the width of an elastic band in the waist of the nappy pants.

According to an aspect, the welding units are positioned relative to each other, along the feed path, by the computerised command and control unit of the processing unit, based on a control signal.

According to an aspect, the control signal is generated by the high level control unit as a function of the width of an elastic band in the waist of the nappy pants.

That way, based on the width of the elastic bands in the waist of the nappy, the welding units are positioned as a function of the weld pitch to be obtained.

According to an aspect, the production line comprises a welding device for welding the elastic bands in the waist of the nappy pants and which comprises at least one welder.

According to an aspect, the welder is driven by the computerised command and control unit of the processing unit and is actuated according to an electronic cam profile based on a control signal.

The control signal is generated by the high level control unit as a function of the width of an elastic band in the waist of the nappy pants. Advantageously, the use of one or more electronic cam welders allows adapting to the welded product spacing variations due to product size changeover.

According to an aspect, the production line comprises a processing unit that comprises a cutting device for separating each pair of nappy pants from a succession of nappy pants that are joined to each other.

According to an aspect, the cutting device comprises a cutter driven by the computerised command and control unit of the processing unit and is actuated according to an electronic cam profile based on a control signal.

The control signal is generated by the high level control unit as a function of the width of an elastic band in the waist of the nappy pants.

Advantageously, the cutting device actuated by an electronic cam allows cutting the nappy pants from the succession of nappy pants in any size.

According to an aspect, the production line comprises a processing unit that comprises a turning and spacing device for turning and spacing the nappy pants of a succession of nappy pants.

The turning and spacing device comprises at least one nappy pants pickup means driven by the computerised command and control unit of the processing unit.

According to an aspect, the pickup means is actuated according to an electronic cam profile based on a control signal generated by the high level control unit as a function of the width of an elastic band in the waist of the nappy pants, which determines the pickup spacing of the nappy pants.

According to an aspect, the control signal is a function of the height of the elastic band in the waist of the nappy pants and of the length of the absorbent pad, which determine, for example, the spacing at which the nappy pants are released.

According to an aspect, the production line comprises a processing unit that comprises a folding device for folding an elastic band in the waist of the nappy pants. The folding device is actuated on the basis of a control signal that is generated by the high level control unit as a function of the width of an elastic band in the waist of the nappy pants and/or of the width of the absorbent pad.

According to an aspect, the folding device is what is known as an active device and is configured to work on an elastic band of any width in the waist of the nappy pants and/or on an absorbent pad of any width.

According to an aspect, the production line comprises a processing unit that comprises a folding device for folding at least the absorbent pad of the nappy pants along a folding line transverse to the absorbent pad.

The folding device is actuated on the basis of a control signal that is generated by the high level control unit as a function of the height of an elastic band in the waist of the nappy pants and/or of the length of the absorbent pad.

According to an aspect, this disclosure relates to a process for the production of nappy pants of the type each comprising at least one absorbent pad and a plurality of elastic bands; the elastic bands and the absorbent pad schematically form a pants-like structure.

According to an aspect, the process comprises a step of forming a composite web to form a composite web from which the absorbent pads will be obtained and a step of forming elastic strips to form the elastic bands.

The process comprises a plurality of steps of processing the composite web, the elastic bands and semi-products derived from the composite web, from the elastic bands or from combinations thereof during processing.

According to an aspect, the process comprises a step of generating, for each processing step, at least one respective control signal as a function of the size of the nappy pants being produced.

According to an aspect, the process comprises a step of adapting each processing step to the size of the nappy pants being produced as a function of the respective control signal.

Advantageously, based on the size to be produced, a respective control signal is generated for each processing step so that each step adapts to the size being produced, that is to say, to the dimensions of the nappy pants to be obtained.

According to an aspect, at least one control signal is generated as a function of the width of the absorbent pad.

According to an aspect, at least one control signal is generated as a function of the length of the absorbent pad.

According to an aspect, at least one control signal is generated as a function of the width of an elastic band in the waist of the nappy pants. According to an aspect, at least one control signal is generated as a function of the height of an elastic band in the waist of the nappy pants. According to an aspect, the production process comprises a step of cutting the composite web to obtain a succession of absorbent pads. The step of cutting is based on a control signal generated as a function of the length of the absorbent pad.

According to an aspect, the production process comprises a step of turning and spacing to space and turn the absorbent pads of a succession of absorbent pads. The step of turning and spacing is based on a control signal generated as a function of the width of an elastic band in the waist of the nappy pants.

In effect, the absorbent pads are advantageously positioned as a function of the spacing they are required to have after the step of turning and spacing for any product size.

According to an aspect, the production process comprises a step of cutting to at least partly cut the elastic bands in a coupling zone where the elastic bands are coupled to the respective absorbent pad.

The step of cutting is based on a control signal generated as a function of the width of an elastic band in the waist of the nappy pants corresponding to a position of the absorbent pad.

According to an aspect, the production process comprises a step of cutting to at least partly shape the elastic bands of the nappy pants.

The step of cutting is based on a control signal generated as a function of the length of the absorbent pad and/or as a function of the width of an elastic band in the waist of the nappy pants and/or as a function of the height of the elastic band in the waist of the nappy pants.

According to an aspect, the step of cutting to at least partly shape the elastic bands of the nappy pants comprises a step of laser cutting and/or a step of waterjet cutting.

According to an aspect, the production process comprises a step of applying a label to each pair of nappy pants.

The step of applying is based on a control signal generated as a function of the width of an elastic band in the waist of the nappy pants.

According to an aspect, the production process comprises a step of welding the elastic bands in the waist of the nappy pants by means of a plurality of welding units.

According to an aspect, the step of welding comprises a step of spacing the welding units along a feed path of the nappy pants to be formed.

According to an aspect, the step of spacing is based on a control signal generated as a function of the width of an elastic band in the waist of the nappy pants.

According to an aspect, the production process comprises a step of cutting to separate each pair of nappy pants from a succession of nappy pants that are joined to each other in a continuous web.

The step of cutting is based on a control signal generated as a function of the width of an elastic band in the waist of the nappy pants.

According to an aspect, the production process comprises a second step of turning and spacing to turn and space the nappy pants of a succession of nappy pants.

The second step of turning and spacing is based on a control signal generated as a function of the width of an elastic band in the waist of the nappy pants and of the height of the elastic band in the waist of the nappy pants.

According to an aspect, the production process comprises a step of folding to fold at least one elastic band in the waist of the nappy pants. The step of folding is based on a control signal generated as a function of the width of an elastic band in the waist of the nappy pants and/or of the width of the absorbent pad.

According to an aspect, the production process comprises a step of folding to fold the absorbent pad of the nappy pants along a folding line transverse to the absorbent pad.

The step of folding is based on a control signal generated as a function of the height of an elastic band in the waist of the nappy pants and/or of the length of the absorbent pad.

Further features and advantages are more apparent in the exemplary, hence non-limiting description which follows of a preferred but non-exclusive embodiment of a line and a process for the production of nappy pants.

With reference to <FIG> and <FIG>, the numeral <NUM> denotes a production line according to this disclosure.

The production line <NUM> is intended for the production of nappy pants of the type represented schematically in <FIG>.

With reference to <FIG>, the numeral <NUM> denotes a pair of nappy pants of substantially known type, described only insofar as necessary for understanding this invention.

The nappy <NUM> essentially comprises an absorbent pad <NUM> and an elastic structure <NUM> for supporting the pad <NUM>.

The elastic structure <NUM> allows the nappy to be worn like a pair of pants by a user not illustrated.

The absorbent pad <NUM> essentially comprises a topsheet, a backsheet and an absorbent pad sandwiched between the two and obtained, as explained below, from a composite web CW.

The structure <NUM> is formed of elastic bands <NUM>, <NUM> that comprise webs of non-woven fabric between which elastics are inserted.

The structure <NUM> essentially comprises an elastic ring that defines the waist <NUM> of the nappy <NUM> and a pair of elastic rings <NUM> that define the openings for the user's legs. The elastic ring <NUM> and the rings <NUM> are formed of elastic bands <NUM>, <NUM>.

The nappy <NUM> has, amongst others, four characteristic dimensions A, B, C and D which, with reference to <FIG>, are the width of the elastic bands in the waist or waist <NUM>, the height of the elastic bands in the waist or waist <NUM>, the length of the absorbent pad <NUM> folded in half and the width of the absorbent pad <NUM>, respectively.

For simplicity, the full length of the pad <NUM> is hereinafter represented by the dimension 2C.

The reference numeral <NUM> in <FIG> denotes a semi-product from which the nappy <NUM> is obtained; the semi-product <NUM> is commonly called H product on account of its shape. The semi-product <NUM> has two elastic bands 103a, 103b joined by the absorbent pad <NUM> stretched out flat.

When the pad <NUM> is folded, the elastic bands 103a, 103b are welded to each other to form the waist <NUM> of the nappy <NUM>.

In the embodiment illustrated, the production line <NUM> comprises a forming unit <NUM> for forming the composite web CW from which, as mentioned, the pads <NUM> are obtained.

The production line <NUM> comprises a forming unit <NUM> for forming elastic bands <NUM>, <NUM> to form the elastic bands <NUM>, <NUM> that are intended, for example, to form the structure <NUM>.

The line <NUM> comprises an assembly line <NUM> having an infeed 4a for the composite web CW formed by the unit <NUM> and an infeed 4b for the elastic bands <NUM>, <NUM> formed by the unit <NUM>.

The assembly line <NUM> has an outfeed 4c for the nappy pants <NUM> made. The assembly line <NUM> comprises a plurality of processing units to construct the nappy pants <NUM> at least from the composite web CW and the elastic bands <NUM>, <NUM>.

The production line <NUM>, and in particular the assembly line <NUM>, comprises the processing units disposed in sequence along a path for the production of the nappies <NUM>.

The term "processing units" is used to denote working units which perform macroscopic operations in the process of manufacturing the nappies <NUM> and which must be adapted, in their functional parameters, to the characteristic dimensions of the nappy <NUM> of the size being made.

In a preferred embodiment, each processing unit comprises a computerised command and control unit which controls the operation of the respective processing unit.

The production line <NUM> comprises a computerised high level control unit HCPU in communication with the computerised command and control units in the assembly line <NUM>.

The high level control unit HCPU is configured to impart to each computerised command and control unit at least one control signal for the respective processing unit as a function of the size of the nappy pants <NUM> being produced in the production line <NUM>. The size, or type, of nappy <NUM> produced is imparted to the production line <NUM> by a line manager.

As will become clearer below, the processing units are each configured to perform a respective process as a function of the size imparted through the respective control signal.

In practice, changing the size of the nappy <NUM> being produced is managed by the HCPU, which drives the command and control units so they adapt the respective processing units to the new size.

Advantageously, the processing units do not require macroscopic mechanical interventions such as, for example, replacement of rotary knives, replacement of wheels with wheels of different diameter, modification of conveyor belts.

That way, interventions on the production line and line downtime are minimised and the time can be used for minor adjustments, for example, modifications to glue dispensers or adjustments to web tension devices, which are in any case inevitable when changing over to a different size.

In an embodiment, at least one control signal generated by the HCPU is a function of the width D of the absorbent pad <NUM>.

In an embodiment, at least one control signal generated by the HCPU is a function of the length 2C of the absorbent pad <NUM>.

In an embodiment, at least one control signal generated by the HCPU is a function of the width A of the elastic band <NUM>.

In an embodiment, at least one control signal generated by the HCPU is a function of the height B of the elastic band <NUM>.

The processing units of the assembly line <NUM> comprise a first processing unit <NUM> for cutting the composite web CW and provided with its own computerised command and control unit CPU5.

The processing unit <NUM> comprises a cutting device, not illustrated, for cutting the composite web to obtain a succession of absorbent pads <NUM>.

The cutting device of the processing unit <NUM> comprises at least a first cutter, driven by the unit CPU5 and actuated according to an electronic cam profile based on a first control signal S5.

The signal S5 is generated by the control unit HCPU as a function of the length of the absorbent pad <NUM>.

In practice, the cutter, movable by the electronic cam, can cut the composite web CW into pieces that define absorbent pads <NUM> of the required length based on the size of the nappy <NUM> being produced and based on the commands of the HCPU.

The processing unit <NUM> allows the length C of the absorbent pad <NUM> to be adjusted automatically.

The production line <NUM>, in particular the assembly line <NUM>, comprises a second processing unit <NUM>, provided with its own computerised command and control unit CPU6, for spacing and rotating the absorbent pads <NUM> of a succession of absorbent pads leaving the processing unit <NUM>.

The processing unit <NUM> is located downstream of the processing unit <NUM> in a production feed direction V of the nappies <NUM>.

The processing unit <NUM> comprises a turning and spacing device of substantially known type and not illustrated.

For example, in an embodiment, the turning and spacing device comprises at least one rotary pickup means for picking up an absorbent pad <NUM>, and a motor, for example, a linear motor, for moving the pickup means.

The turning and spacing device, in particular the linear motor, is driven by the computerised command and control unit CPU6 of the processing unit <NUM> and is actuated according to an electronic cam profile based on a control signal S6.

The control signal S6 is generated by the control unit HCPU as a function of the width A of the waist <NUM> of the size of the nappy <NUM> being produced.

That way, the absorbent pads <NUM> are positioned according to how they are to be coupled to the corresponding elastic bands <NUM>, <NUM>.

In practice, the processing unit <NUM> allows picking up the absorbent pads <NUM> based on their length C, which varies continually as a function of the size, and placing the absorbent pads <NUM> on the elastic bands <NUM>, <NUM>, whose length A, in the finished product, varies continually as a function of the size of the nappy <NUM>.

The processing unit <NUM> allows picking up the absorbent pads <NUM> according to one spacing which varies on the basis of the size and places them according to another spacing, also variable on the basis of the size of the nappy <NUM>.

The processing units of the production line <NUM> comprise a processing unit <NUM>, of substantially known type, for coupling the elastic bands <NUM>, <NUM> to the absorbent pads <NUM>. In practice, the processing unit <NUM> defines a coupling station with semi-products <NUM> moving along downstream of it in uninterrupted succession.

In an embodiment, the processing units of the production line <NUM> comprise a third processing unit <NUM>, provided with its own computerised command and control unit CPU8, for at least partly cutting the elastic bands <NUM>, <NUM>, in particular, the elastics present therein, in a coupling zone <NUM> where the elastic bands <NUM>, <NUM> are coupled to the respective absorbent pad <NUM>.

The unit <NUM> comprises a cutting device of substantially known type, not illustrated, provided with at least one cutter driven by the computerised unit CPU8.

The cutter is actuated according to an electronic cam profile based on a control signal S8 generated by the HCPU as a function of the width A and/or of the width D.

Preferably, the processing unit <NUM> is located downstream of the processing unit <NUM> in a production feed direction V of the line <NUM> for the production of the nappies <NUM>.

The elastics of the elastic bands <NUM>, <NUM> are, for example, cut at the ends of the absorbent pad <NUM> so as not to tighten it and not affect its absorbent properties.

In an embodiment, for example if the nappy <NUM> requires it, the processing units of the production line <NUM> comprise a fourth processing unit <NUM>, provided with its own computerised command and control unit CPU9, for at least partly shaping the elastic bands <NUM>, <NUM>.

The elastic bands <NUM>, <NUM>, for example, may be shaped to enhance the comfort of the nappy <NUM>.

The processing unit <NUM> comprises a laser or waterjet cutting device driven by the computerised unit CPU9 based on a control signal S9.

The control signal S9 is generated by the HCPU as a function of the length C and/or as a function of the width A and/or as a function of the height B.

The waterjet or laser cutting device allows shaping the product in any way, in particular on the basis of the size of the nappy <NUM> being produced, as set by the HCPU.

For example, the elastic band <NUM>, <NUM> used in the production of the nappy <NUM> has an oversize dimension and is then radiused/trimmed.

In an embodiment, the processing units of the production line <NUM> or of the assembly line comprise a fifth processing unit <NUM>, provided with its own computerised command and control unit CPU10, for applying a label <NUM> to the nappy <NUM>; in <FIG>, the label <NUM> is drawn with a dashed line because it is optional.

The processing unit <NUM> comprises an applicator, of known type and not illustrated, for applying the label <NUM> to each pair of nappy pants <NUM>.

The applicator is driven, for example, by an electronic cam controlled by the unit CPU10, based on a control signal S10.

The control signal S10 is generated by the high level control unit HCPU as a function of the width A so that the label <NUM> is positioned relative thereto.

The processing unit <NUM> is preferably located downstream of the processing unit <NUM> in a production feed direction V of the line <NUM> for the production of the nappies <NUM>.

In an embodiment, the processing units of the production line <NUM> or of the assembly line <NUM> comprise a sixth processing unit <NUM>, provided with its own computerised command and control unit CPU11, for welding the elastic bands <NUM> in the waist of the product.

The processing unit <NUM> is located at least downstream of the processing station <NUM> and downstream of a system, not illustrated, which folds the semi-product <NUM> in the form of a web comprising the elastic bands <NUM>, <NUM> and the absorbent pads <NUM> by <NUM>° so that the elastic bands <NUM> that will form the waist of the nappy pants <NUM> are positioned face to face.

In an embodiment, the processing unit <NUM> comprises a welding device for welding the elastic bands <NUM> in the waist of the nappy pants <NUM> and which comprises, for example, a plurality of welding units spaced from each other along a feed path of the nappy pants <NUM> to be formed. An example of such a unit is described in document <CIT>.

The welding units are spaced as a function of the width A and are positioned relative to each other, along the feed path, by the computerised command and control unit CPU11, based on a control signal S11.

The control signal S11 is generated by the control unit HCPU as a function of the width A.

Downstream of the processing unit <NUM> there is thus a succession of formed nappy pants <NUM> joined to each other along the lateral welds. Advantageously, using a welding unit that can vary its weld pitch allows making nappies <NUM> in any size.

In an embodiment, the processing unit <NUM> comprises a welding device that comprises at least one welder, driven by the computerised unit CPU11 and actuated according to an electronic cam profile based on the control signal S11.

The signal S11 is generated by the control unit HCPU as a function of the width A. By adapting the electronic cam profile to the size being produced, the welding device allows welding nappies <NUM> of any size. The processing units of the production line <NUM>, and in particular of the assembly line <NUM>, comprise a seventh processing unit <NUM>, provided with its own computerised command and control unit CPU12, for separating each pair of nappy pants <NUM> from a succession of nappy pants that are joined to each other.

The processing unit <NUM> is located downstream of the processing unit <NUM> in a production feed direction V of the line for the production of the nappies <NUM> and comprises a fourth cutting device of substantially known type and not illustrated.

The cutting device of the processing unit <NUM> comprises at least one cutter, driven by the computerised unit CPU12 and actuated according to an electronic cam profile based on a control signal S12.

The control signal S12 is generated by the control unit HCPU as a function of the width A to separate nappies <NUM> of any size from each other.

The processing units of the production line <NUM>, and in particular of the assembly line <NUM>, comprise an eighth processing unit <NUM>, provided with its own computerised command and control unit CPU13, for spacing and turning the nappy pants <NUM>.

The processing unit <NUM> is located downstream of the processing unit <NUM> in the production feed direction V of the line for the production of the nappies <NUM> to space and turn the nappy pants <NUM> which have been separated from each other in the processing station <NUM>.

The processing unit <NUM> comprises a turning and spacing device which comprises at least one rotary means for picking up a pair of nappy pants <NUM>.

The rotary pickup means is driven by the computerised unit CPU13 and is actuated, in its travel, according to an electronic cam profile based on a control signal S13.

The signal S13 is generated by the control unit HCPU as a function of the width A and of the heights B and C.

In practice, the infeed of the processing unit <NUM> receives an incoming succession of products whose spacing is a function of A and which, at the outfeed, are repositioned according to a spacing that is a function of B and C. Advantageously, in particular by using the electronic cam profile, the processing unit <NUM> can pick up according to any spacing and return at any spacing, thus adapting to all the possible size variations of nappies <NUM>.

The processing units of the production line <NUM> and, in particular, of the assembly line <NUM> comprise a ninth processing unit <NUM>, provided with its own computerised command and control unit CPU14, for folding the elastic bands <NUM> in the waist of the nappy <NUM> on the absorbent pad <NUM>.

The waist <NUM> of the nappy <NUM> is folded along at least one longitudinal fold line, that is a fold line parallel to the feed direction of the products. As a function of the width A, the processing unit <NUM> can also be configured to make two or more folds along longitudinal fold lines. The processing unit <NUM> comprises a folding device actuated on the basis of a control signal S14.

The control signal S14 is generated by the control unit HCPU as a function of A and/or as a function of D.

The folding device is preferably an active device and sized to handle elastic bands of any width.

The processing units of the production line <NUM>, and in particular of the assembly line <NUM>, comprise a tenth processing unit <NUM>, provided with its own computerised command and control unit CPU15, for folding at least one absorbent pad <NUM> of the nappy pants <NUM>.

Folding the absorbent pad <NUM> occurs along a fold line transverse to the feed direction of the products.

The processing unit <NUM> comprises a folding device actuated on the basis of a control signal S15.

The control signal S15 is generated by the control unit HCPU as a function of the height A and/or of the length C.

The production line <NUM>, where each processing unit is provided with its own computerised control unit controlled by a single computerised high level control unit HCPU, can, based on input imparted by the latter, adapt production to any required size of nappy <NUM>.

In particular, thanks to their architecture, all the units described comprise operating devices which do not necessitate macroscopic mechanical interventions or, in any case, which do not necessitate human intervention or prolonged machine downtime.

A process for the production of nappies <NUM> comprises a step of forming a composite web CW to form the composite web CW from which the absorbent pads <NUM> are obtained. The step of forming the composite web CW is substantially known and not further described.

The process comprises a step of forming elastic bands or strips to form the elastic bands <NUM>, <NUM> of the nappy <NUM>.

The process comprises a plurality of steps of processing the composite web CW, the elastic bands <NUM>, <NUM> and semi-products <NUM> derived from the composite web CW and from the elastic bands <NUM>, <NUM>, as illustrated, for example, in <FIG>.

The process comprises a step of generating, for each processing step, at least one respective control signal S5, S6, S8, S9, S10, S11, S12, S13, S14, S15 as a function of the size of the nappy pants <NUM> being produced.

The process comprises a step of adapting each processing step to the size of the nappy pants <NUM> being produced as a function of the respective control signal.

In an embodiment, at least one control signal is generated as a function of the width D of the absorbent pad <NUM>.

In an embodiment, at least one control signal is generated as a function of the length C of the absorbent pad <NUM>.

In an embodiment, at least one control signal is generated as a function of the width A of the waist <NUM> of the nappy pants <NUM>.

In an embodiment, at least one control signal is generated as a function of the height B of the waist <NUM> of the nappy pants <NUM>.

In an embodiment, the process comprises a step of cutting the composite web CW to obtain a succession of absorbent pads <NUM>.

The step of cutting the composite web CW is based on a control signal S5 generated as a function of the length 2C of the absorbent pad <NUM>. In an embodiment, the process comprises a step of turning and spacing to space and turn the absorbent pads <NUM> of a succession of absorbent pads <NUM>.

The step of turning and spacing the absorbent pads <NUM> is based on a control signal S6 generated as a function of the width A.

In an embodiment, the process comprises a step of at least partly cutting the elastic bands <NUM>, <NUM> in a coupling zone <NUM> where the elastic bands <NUM>, <NUM> are coupled to the respective absorbent pad <NUM>.

The step of cutting the elastic bands <NUM>, <NUM> in a coupling zone <NUM> where the elastic bands <NUM>, <NUM> are coupled to the respective absorbent pad <NUM> is based on a control signal S8 generated as a function of the width A.

In an embodiment, the process comprises a step of cutting to at least partly shape the elastic bands <NUM>, <NUM>.

The step of cutting to shape the elastic bands <NUM>, <NUM> is based on a control signal S9 generated as a function of the length 2C of the absorbent pad <NUM> and/or as a function of the width A and/or as a function of the height B.

In an embodiment, the step of cutting to shape the elastic bands <NUM>, <NUM> comprises a step of laser cutting and/or a step of waterjet cutting. In an embodiment, the process comprises a step of applying a label <NUM> to each pair of nappy pants <NUM>.

The step of applying is based on a control signal S10 generated as a function of the width A.

In an embodiment, the process comprises a step of welding the elastic bands <NUM> in the waist of the nappy pants <NUM> by means of a plurality of welding units.

In an embodiment, the step of welding comprises a step of spacing the welding units along a feed path of the nappy pants <NUM> to be formed. The step of spacing is based on a control signal S11 generated as a function of the width A.

In an embodiment, the process comprises a step of cutting to separate each pair of nappy pants <NUM> from a succession of nappy pants that are joined to each other.

The step of cutting to separate each pair of nappy pants <NUM> from a succession of nappy pants that are joined to each other is based on a control signal S12 generated as a function of the width A.

In an embodiment, the process comprises a step of turning and spacing to space and turn the nappy pants <NUM> of a succession of nappy pants <NUM>.

The step of turning and spacing the nappy pants <NUM> is based on a control signal S13 generated as a function of the width A and/or of the height B and/or of the length 2C.

In an embodiment, the process comprises a step of folding at least one elastic band <NUM> in the waist of the nappy pants <NUM>.

The step of folding is performed along a longitudinal folding line parallel to a feed direction of the products.

The step of folding is based on a control signal S14 generated as a function of the width A and/or of the width D.

In an embodiment, the process comprises a step of folding to fold the absorbent pad <NUM> of the nappy pants <NUM>.

The step of folding the absorbent pad <NUM> is performed along a fold line transverse to a feed direction of the products.

Claim 1:
A line (<NUM>) for the production of nappy pants (<NUM>) of the type each comprising at least one absorbent pad (<NUM>) and a plurality of elastic bands (<NUM>, <NUM>), said elastic bands (<NUM>, <NUM>) and said absorbent pad (<NUM>) defining together a pant structure (<NUM>), said production line (<NUM>) comprising a first forming unit (<NUM>) for forming a composite web (CW) from which said absorbent pads (<NUM>) are obtained, a second unit (<NUM>) for forming elastic bands (<NUM>, <NUM>) for forming said elastic bands (<NUM>, <NUM>) and an assembly line (<NUM>) having a first infeed (4a) for said composite web (CW), a second infeed (4b) for said elastic bands (<NUM>, <NUM>) and an outfeed (4c) for said nappy pants (<NUM>), said assembly line (<NUM>) comprising a plurality of processing units to construct said nappy pants (<NUM>) starting at least from said composite web (CW) and from said elastic bands (<NUM>, <NUM>), wherein said processing units each comprise a computerised command and control unit and wherein said production line (<NUM>) comprises a computerised high level control unit (HCPU) in communication with said computerised command and control units in the assembly line (<NUM>), said high level control unit (HCPU) being configured to impart to each computerised command and control unit at least one control signal for the respective processing unit as a function of the size of the nappy pants (<NUM>) being produced in the production line (<NUM>), said processing units being configured to perform a respective processing as a function of the format set using the respective control signal.