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FIELD OF APPLICATION

The present invention relates to a sewing machine provided with a flexible modular system for the simplified variation of the needle gauges.

More specifically the present invention relates to industrial sewing machines with multiple needles, of the double-chain stitch type (also called 401 stitch) , having in the lower sewing part a series of frontal-movement loopers, and lateral-movement hook spreader plates adapted to realise multiple seams at the same time on any item of clothing.

Typically industrial-type sewing machines with multiple needles are used in the fabric or leather apparel manufacturing sector, and are combined with a guide fabric to be used for the production of braces or to apply the lumbar band, also called belt, to a panel of material, or in general to trousers or jackets.

This modular system according to the invention used on sewing machines with multiple needles, having a series of frontal-movement loopers in the lower sewing part, makes it possible to have greater flexibility and possible combinations of the various needle gauges and eliminates the need to carry out a series of laborious operations to configure the sewing machine according to needs, as notoriously, together with the needles when the configuration must be changed, all the other lower sewing members which are associated with the double-chain stitch or 401 stitch must also be correctly and quickly prepared .

The present invention is advantageously applied in the field of industrial sewing machines and in particular to sewing machines with multiple needles for double or quadruple seams with a double-chain stitch, or 401 stitch, having a series of frontal-movement loopers in the lower sewing part.

PRIOR ART

It is known in the art that industrial-type sewing machines are made and configured to perform processes of varying nature depending on the type of seam that must be obtained .

In the field of jeans, which is one of the most popular types of apparel, it is envisaged that for the realisation of the lumbar band called "belt", industrial sewing machines are used which have multiple needles that make it possible to create parallel and simultaneous seams along the two edges of the same belt band, so as to give the jeans the classic structure with the seams standing out with respect to the fabric, in order to increase the robustness of the union between fabrics or even only for ornamental purposes.

To carry out these operations, normally sewing machines are used which have multiple needles that allow the machine to sew a double-chain stitch or stitches which are also known in the sector as 400 class stitches and are formed by two or more threads, coming from reels outside the machine. The double-chain stitch is formed by the linking of two threads, one carried by the needle and the other by a looper that can have frontal or lateral movement .

These sewing machines have a group of upper needles, where each needle is associated below with a frontal- movement looper and a transverse-movement hook spreader device, which with their synchronism make it possible to carry out the double-chain stitch, also called 401 stitch, sewing operations.

Normally each adjacent pair of needles present in these sewing machines is supported at the top by a single clamp, fixed to the base of the needle bar, which is in turn provided with suitable seats where the needles are positioned and fixed, and through which the two threads, coming from respective reels located in the upper part of the machine body, are inserted and slide.

Similarly each adjacent pair of needles which receives the upper thread, is associated with respective mechanical members below, placed under the sewing plane, which receives the lower thread, represented by hooking and displacement devices of the upper thread called loopers, which in this specific case follow a frontal movement and are equipped with a curved and sharp hook adapted to allow the upper thread to be concatenated, through the movement of the lateral-movement hook spreader device, with the lower thread during the advancement of the fabric, forming the double-chain stitches, or 401 stitch.

The main drawback encountered with the use of such frontal-movement looper machines is represented by the fact that the seams that are realised with the upper needles can require a variable distance between the various parallel left and right seam lines, depending on the processing to be carried out.

Typically needle gauges can be used with a fixed pitch between the needles, according to a multiple between 1/4" and 1/8", and in these cases known in the prior art of lateral-movement looper sewing machines, normally suitable dedicated kits are used, each with specific and fixed distances between the distance of the pairs of upper right and left needles, and thus all the associated lower stitching members, which however bring the need to completely change the entire kit when the dedicated distance must be changed between a pair of left and right needles or if the kit has not already been pre set to the required distance, with the consequent loss of time by operators, and also with the further need to purchase and have all the various accessories depending on the type of belt to realise.

In particular, with reference to figures 1 to 3 which represent the prior art, the interchangeable elements are represented by a needle clamp 10, a left presser foot sole 8, a right presser foot sole 9, the needle plate 13, the spreader 12 with the hook spreaders in a fixed distance and the main looper carrying clamp 11.

In any case the normal distance between the pairs of needles is 1/4", and this represents a limitation because the fashion industry increasingly requests the possibility of realising minimum needle distances up to 1/8".

It can therefore be appreciated that by using a specific kit dedicated to only one requested type of measurement on a frontal-movement looper machine, the replacement, disassembly and reassembly of all the components involved entails considerable inconvenience in terms of economic investment and the time spent by operators .

These limitations negatively affect the production capacity of the companies which use the known machines, limiting their production flexibility with a possible loss of competitiveness with respect to competitors. The solution referred to in document W02005/091979 is also known in the art, which envisages the use of a modular system for the variation of the types of needles and their connected mechanisms to obtain a machine that, through the replacement of certain elements, makes it possible to vary the configuration by changing the interaxis between the needles, making the machine more versatile and adapted to a variety of operations, each with a different pitch of the sewing mechanisms.

However this solution is extremely complex as well as very bulky and not adapted to performing traditional- type sewing operations with multiple needles.

DESCRIPTION OF THE INVENTION

The present invention proposes to provide a sewing machine with multiple needles, with the double-chain stitch, or 401 stitch type, and having in the lower sewing part a series of frontal-movement loopers, and lateral-movement hook spreaders, forming part of a modular and flexible system for the facilitated variation of the seam distance present in any sewn garment, for example in braces or in a preformed belt, wherein the possible pairs of parallel seams present on the upper and lower side can be selected from various needle gauges, using standard gauges with the measurement of 1/8" and 1/4", but that can also have any other dedicated measurement, thus creating a flexible and incomparable condition able to eliminate and/or at least reduce all the above drawbacks .

The invention aims in particular to provide a sewing machine with multiple needles, with the double-chain stitch or 401 stitch type, and having a series of frontal-movement loopers in the lower sewing part, provided with a flexible modular system for the variation of the needle gauges which envisages using a single modular kit of components that makes it possible to realise all the obtainable configurations without the need to replace the basic components.

Another object of the invention is to provide a sewing machine that makes it possible to vary the needle pitch in a flexible and modular way, between minimal interaxes, such as 1/8" and 1/4" pitches, and/or any other desired measurement, a characteristic that is not currently possible to obtain using the traditional sewing units known in the market with the double-chain stitch or 401 stitch type and having a series of frontal-movement loopers in the lower sewing part.

This is achieved by means of a sewing machine provided with a flexible modular system for the facilitated variation of the needle gauges, whose characteristics are described in the main claim.

The dependent claims of the solution in question describe advantageous embodiments of the invention in which the possibility of quickly setting a sewing machine with multiple needles is highlighted, with movement of the lower looper, to quickly pass from one configuration to the other in a modular and flexible way.

The main advantages of this solution are related to the fact that the main plate comprises a modular and flexible system of dedicated inserts, with or without specific slots provided, which are fixed to the main plate. The inserts are made in a specific way and are adapted to be used in both the right side and left side of the main needle plate.

These modular inserts with slots are interchangeable, as each is made in a different way and has a distance between the slots which is calculated on the basis of the requested size.

In a machine made in this way, if the pitch must be changed, only the dedicated inserts must be replaced or moved, which are fixed to the main plate to vary the type of seam requested.

It is also envisaged that said modular inserts in some cases comprise a specific lower tooth positioned between the two slots, having the function of maintaining the thread exiting the left looper out of the range of the needle positioned inside the right slot, while the lower left thread is pushed/pulled toward the right by the specific lateral movement of the hook spreader.

The system of the invention further envisages that the fixing system of the pair of frontal-movement hooks is placed on a lower specific block which is dedicated to the requested measurement.

The lower block is mounted on a main support with multiple seats. This main support makes it possible to vary the position of the blocks installed on the basis of the requested distance of the needles. Only two blocks are applied to the main support each time, making it possible to limit the mass applied to the kinematic movement of the frontal linkage movement of the loopers, and thus makes it possible to create seams at maximum speed without damaging the internal members of the machine .

The system of the invention further envisages that the spreader assembly is formed by several components, a main body with multiple seats and a specific series of double-point hook spreaders, with different lengths to pull the lower thread, and dedicated distances for the requested measurement which are specific for the right side and left side of the seam.

These components are mounted on the main support of the spreader only for the hook spreaders requested based on the measurement requested on the right and left side, obtaining the reduction of applied inertia and allowing the machine to sew at maximum speed.

A specific knife cuts the lower thread, is inserted behind each insert with the slots and is applied to the main plate.

This knife has a particular shape that allows it to be rotated with respect to its own axis according to the insert with the slots used.

The knife serves to cut the upper thread while the function of opening or un-stitching the preformed belt is performed.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the invention will become apparent from reading the following description of an embodiment of the invention provided by way of non-limiting example with the aid of the figures illustrated in the appended tables of drawings, in which: figures 1 to 3 schematically show views of a traditional-type sewing machine with multiple needles ;

figure 4 shows a schematic axonometric view referring to the industrial sewing machine with multiple needles with a flexible and modular system for changing the seam measurement according to the invention as a whole and in a partially exploded view;

figure 5 shows a schematic axonometric view referring to the industrial sewing machine with multiple needles with a flexible and modular system for changing the seam measurement according to the invention in its partially assembled entirety;

figure 6 shows a schematic view of the machine according to the invention in plan view with all the modular components separated and ready for selective installation in the appropriate seats;

figure 7 is a view of some modular inserts which can be used in the machine according to the invention; figure 8 shows a plan view of a modular plate that represents the working plane of the machine;

figures 9 to 11 show views of the modular plate according to the invention in three distinct operating configurations, i.e. some of the possible various combinations with the appropriate positioning of the inserts.

DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

With reference to the accompanying figures, and initially and especially figure 4, reference number 30 generally indicates an industrial sewing machine with multiple needles with a flexible and modular system for changing the seam measurement in its entirety, which comprises a series of components assembled together, the main ones represented by a needle clamp 31 into which needles 32 are inserted, which is placed in the upper part, associated with a left presser foot sole 33 and a right presser foot sole 34.

In accordance with the embodiment illustrated in figure 4, the industrial sewing machine with multiple needles provided with a flexible and modular system for changing the seam measurement according to the invention, further comprises a main plate 35 arranged on the sewing plane, below which a spreader 36 is in turn arranged in a frontal position, which is placed in the middle between the plate 35 and a modular central support with multiple seats 37 to which specific blocks 43 supporting loopers 45 are placed.

A peculiarity of the invention is given by the fact that each of these main supporting components can be combined with a plurality of interchangeable modular components that make it possible to obtain the desired configuration by means of a quick and easy variation of the pitch between the needles 32 and their respective associated components.

In particular, by keeping the order of the components listed, the needle clamp 31 comprises a plurality of holes positioned at a close interaxis, adapted to allow the positioning and fixing of the needles at the desired inter-distance, using a wide range of possible positions.

In figures 5 and 6, which show the interchangeable modular components, the presence of a needle clamp 31 and a needle clamp aperture 31' can be noted, which is placed and fixed to the top of the clamp itself.

Similarly, as shown in figures 5, 6 and 7, openings or windows 39 and 39' are formed at the central part of the plate 35, which are adapted to receive different types of modular plates 40 created for the purposes described below, some of which comprise slots 41 arranged in pairs with different interaxes, said slots being provided to be crossed by the needles 32 while they move to inside the slots themselves, and the loopers 45 move in a frontal manner toward the spreader 36.

The loopers 45 are inserted with their stem inside holes 44 in the clamp 43, and in turn the same clamps 43 are then fixed to the main modular support with multiple seats 37 carrying the clamps 43, the hooks 45 of which will be discussed below.

Knives 42 are fixed below the main plate 35 which can be positioned and rotated along their axis based on the type of plates 40 used.

The spreader 36 comprises a main body with multiple seats and is responsible for retaining the interchangeable hook spreader plates 38.

The spreader 36 comprises respective holes 36' with a closer inter-distance such that the respective hook spreader plates 38 are positioned correctly with respect to the loopers .

The main modular support with multiple seats 37 placed in the lower part of the machine 30 is used to support and retain modular clamps 43 which in turn comprise holes 44 for housing the loopers 45 which, in operation, are arranged upwards with respect to the main support 37, with the tips facing toward the spreader 36, and with a frontal movement that makes it possible to intercept the threads exiting from the upper needles 32 such that they interweave with the threads of the hooks.

The modular clamps 43 are made in different types depending on the position of the hooks 45 fixed on the clamps themselves at the holes 44. Also in this case, the modular clamps 43 are chosen from those that comprise holes 44 having an inter-distance corresponding to the inter-distance between the needles 32 in turn positioned in the pre-chosen holes on the clamps 31, so that the process is always compliant with the work standards set.

According to an important aspect of the invention shown in figures 4 to 11, the modular plates 40 are realised according to certain typologies, each of which envisages the variation of the position of the slots 41 that can be closer to or further from one another or slightly staggered with respect to one another according to the distance and position set on the needles 32, or based on the presence or absence of the slots 41.

More precisely, with reference to figures 7 to 11, it can be noted that the modular plates 40 are diversified according to their function and placement within the respective apertures or windows 39 and 39', and are respectively represented by half blind plates 40a, blind plates 40b, 1/8" needle plates 40c shifted right, needle plates 40d shifted left and 1/4" needle plates 40e.

In the embodiments shown in figures 9 to 11, three possible configurations are shown with plates located in various ways depending on the type of processing.

For example, figure 9 shows positioned in the window 39 in sequence two half blind plates 40a, a blind plate 40b, and a 1/8" needle plate 40d, while in the right window 39' the 1/8" needle plate 40c is inserted. This configuration is therefore related to the following: right needles distance 1/8" left needles distance 1/8" external/external needles distance 1 1/4".

Similarly the configuration of figure 10 relates to the following: right 1/8" needle plate 40c, left 1/8" needle plate 40d, external/external needle distance 2 1/4" .

Figure 11 shows a configuration which envisages: right 1/4" needle plate 40e, 1/8" needle plate 40d at centre left, external/external distance 1 3/4".

By combining the different plates, all the configurations can therefore be realised.

Moreover certain plates 40, in particular those with slots of the 1/8" type or with measurements less than 1/4", have a specific lower tooth 46 positioned between the two slots 41 that makes it possible to maintain the thread exiting the left looper 45 outside the range of the needle positioned inside the right slot, while the lower left thread is pushed/pulled toward the right by the specific lateral movement of the hook spreader.

All the relative sewing members and accessories envisage the same principle of modularity in order to allow the setting of the machine in the desired configuration ready for sewing with few and simple replacements, without therefore having to carry out the traditional long and laborious transformations.

It can be noted in figure 5 that in the case wherein the needles 32 are particularly close, the same are slightly staggered from one another so as not to obstruct the threading operation.

Furthermore, the modular inserts 40 have a perimeter-like shape adapted to make it possible for the placement of some of them to occupy the space defined by the apertures or windows 39 and 39' of the plate 35 adapted to receive the same modular plates 40 after they have been chosen among those which match the selected configuration of the needles.

We shall now briefly describe an example of a working configuration of the industrial modular and flexible sewing machine for the variation of the seam measurements according to the invention.

The first envisages the disassembly of the plates 40 of the previous configuration as well as the removal of the clamps 43 carrying the hooks 45.

It then envisages the disassembly of the needles 32 and their displacement into the seats of the clamp 31 which are most suited depending on the inter-distance necessary for the arrangement of the needles, being able to choose between the many holes, also having distances very near to each other in the range of 1/8".

At this point the plates 40 necessary for the selected configuration of the needles are chosen, choosing between the pitch that corresponds to the inter distance between the needles themselves.

Below, the hook spreader plates 38 of the spreader 36 are displaced and the clamps 43 are replaced, choosing from those whose wholes 44 carrying the hooks 45 are associated with the selected configuration of the needles .

After all the replaced modular components have been fixed, the processing can be initiated, which is performed after a quick and easy setting of the configuration .

The invention has been described in the foregoing with reference to a preferential embodiment thereof. However it is clear that the invention is susceptible to numerous variants which fall within the scope thereof, and which are technically equivalent.

For example, it can be envisaged that the plates and all the modular components can have different shapes and measurements between the needles with respect to those described and illustrated, while remaining within the scope of protection of the patent.

Furthermore, by preparing the specific modular pieces, seams can also be realised with up to three needles per seam side, having a 1/8" typology, and therefore a total of six needles simultaneously.