EP0298880B1 - Improvements to sewing machines for joining two knitted pieces with a ribbed edge and a long jersey field - Google Patents

Description

The present invention relates to an improvement made to sewing machines, making it possible to sew knitted panels used in the production of clothing such as pullovers, skirts ...

It relates more particularly to an improvement made to sewing machines of the cup type used to carry out the assembly of knitted panels of the "fully-fashioned" type and which, in general, have a ribbed edge extended by a part jersey, an improvement which not only facilitates the use of such machines and increases output, but also ensures better finishing of the articles produced.

In the following description, the improvement in accordance with the invention will be described in the case of the production of panels intended to form a sweater, but it is obvious that this is not limiting and that such a type of machine could be used to make any other type of clothing.

To date, to assemble by stitching knitted panels of the "fully fashioned" type intended to form sweaters, and especially for assembling the front and back panels, and closing the sleeves, uses a special sewing machine called "cuvettes".

These panels generally comprise a part knitted in ribs, called ribbing, on the belt and on the wrists, and a part knitted in jersey along the body and arms. Since the edge of the jersey part tends to roll, the sewing machines with cuvettes are generally equipped with a system for unwinding and guiding the edges of the jersey, a system essentially consisting of a separator (thin vertical plate) associated with two shoes arranged on either side of said separator, ensuring the unrolling and positioning of the selvedges and further equipped with two nipples crossing the hooves and lowering the selvedges to a constant height.

This unwinding system, which should only work in the jersey part, is generally retracted during the sewing of the ribbing and is put in place when the transition zone between ribbing and jersey arrives at the entrance to the sewing machine .

To date, the implementation of such machines is essentially manual and therefore requires highly trained personnel.

It has been proposed for a long time to automate the production of such seams as is apparent in particular from French patents 2 202 520 and 2 247 101.

If in general, the solution which is the subject of the aforementioned patents is satisfactory, it must however be noted that it leads to a very complex assembly, delicate to implement and moreover very bulky.

• d'une glissière de guidage constituée de deux plaques coplanaires horizontales entre lesquelles est ménagée une fente de largeur approximativement égale à l'épaisseur de l'ensemble à coudre
• d'un dispositif de préhension de l'extrémité des panneaux à coudre, et de mise sous tension.

It has also been proposed to simplify the use of sewing machines with cuvettes by providing them:

• a guide rail consisting of two horizontal coplanar plates between which is formed a slot of width approximately equal to the thickness of the sewing assembly
• a device for gripping the end of the panels to be sewn, and for tensioning.

• une lame séparatrice fine, verticale, séparant les deux panneaux de jersey. elle ne pénètre dans la glissière que pendant la couture du jersey et est relevée pendant la couture du bord côte
• deux sabots dérouleurs situés de part et d'autre de la lame séparatrice, mobiles autour d'un axe horizontal et serrant chaque panneau de jersey contre cette lame au moyen d'un ressort de rappel. Ces sabots sont ouverts assez largement pendant la couture du bord cote pour ne pas être en contact avec lui et doivent être amenés au contact de l'article dès la fin du bord cote et le début du jersey. Des moyens mécaniques simples peuvent commander l'ouverture des sabots à partir du mouvement de relevage de la lame séparatrice.
• deux tétons fixes, perpendiculaires à la lame séparatrice. Ils traversent les sabots par un orifice présentant un jeu suffisant pour permettre le réglage des tétons en hauteur et l'ouverture des sabots sans frottement. L'extrémité des tétons et en contact avec la lame séparatrice.

This set indeed makes it easier to sew knitted panels on a cuvette machine but only partially responds to the problem posed. Indeed, the unwinding head associated with the slide is of conventional design and includes:

• a thin, vertical separating blade, separating the two panels of jersey. it only enters the zipper during sewing of the jersey and is raised during the sewing of the ribbing
• two unwinding shoes located on either side of the separating blade, movable around a horizontal axis and pressing each jersey panel against this blade by means of a return spring. These clogs are opened wide enough during sewing of the rib edge so as not to be in contact with it and must be brought into contact with the article from the end of the rib edge and the start of the jersey. Simple mechanical means can control the opening of the shoes from the lifting movement of the separating blade.
• two fixed nipples, perpendicular to the separating blade. They pass through the hooves through an orifice having sufficient clearance to allow the height of the nipples to be adjusted and the hooves to open without friction. The end of the nipples and in contact with the separating blade.

• la pression des ressorts des sabots crée un frottement important entre les panneaux de jersey d'une part et les sabots et la lame séparatrice d'autre part. Ce frottement doit être vaincu par une traction importante des cuvettes qui allonge le jersey, amplifie des éventuelles différences de longueur des panneaux et gène le déroulage
• le jeu important qui existe dans l'orifice des sabots, autour des tétons, ajoute aux effets décrits ci-dessus en créant une zone de discontinuité créatrice de frottements supplémentaires
• les tétons fixes sont un obstacle lors de la couture des bords cotes

This unwinding assembly has a number of drawbacks

• the pressure of the shoe springs creates significant friction between the jersey panels on the one hand and the shoes and the separating blade on the other. This friction must be overcome by a significant pull of the cups which lengthens the jersey, amplifies possible differences in length of the panels and hinders the unwinding
• the important play which exists in the hole of the hooves, around the nipples, adds to the effects described above by creating a zone of discontinuity creating additional frictions
• fixed nipples are an obstacle when sewing the side edges

However, we have found, and this is what is the subject of the present invention, an improvement to the unwinding devices associated with sewing machines with cuvettes, which makes it possible to solve these problems by notably reducing the friction of the knitting in the head. unwinding and removing any obstacle to the passage of the ribs

In general, the invention therefore relates to a guide and unwinding device for cuvette machine making it possible to sew two knitted panels comprising a long jersey possibly preceded by a rib, device having, upstream of the head sewing proper, two coplanar guide slides (plates) whose spacing is adjustable and a set of unwinding located above said slide and itself consisting of a separating blade and two unwinding shoes, the device being characterized in that it comprises two deflection plates located between the separating blade and the unwinding shoes, plates whose thickness is close to l '' thickness of the jersey knit, the lowest part of which is located at a distance from the slides adjustable according to the desired seam fineness, plates which rise at the same time as the separating blade when sewing the rib edges.

Thanks to such an unwinding device, it is possible to sew the ribbed edges without any obstacle and to sew the jersey parts with a minimum of tension, because the friction between the knitting on the one hand, the hooves and the separating blade d on the other hand, is limited to the bare minimum.

• les figures 1 à 4 sont des vues schématique d'un dispositif de guidage et de déroulage réalisé avec des moyens connus ; les figures 1 et 2 le représentent ouvert pour la couture des bords côtes, respectivement en coupe (fig. 1) et de profil (fig. 2). Les figures 3 et 4 le représentent fermé pour le déroulage et la couture du jersey, respectivement en coupe (fig. 3) et de profil (fig. 4)
• les figures 5 à 8 sont des vues schématiques d'un dispositif de déroulage conforme à l'invention. Les figures 5 et 6 le représentent ouvert pour la couture d'un bord côte, respectivement de face (fig. 5) et de profil (fig. 6). Les figures 7 et 8 le représentent fermé pour le déroulage et la couture du jersey, respectivement de face (fig. 7) et de profil (fig. 8).

The invention and the advantages which it brings will however be better understood thanks to the example of embodiment given below by way of indication but not limitation, and which is illustrated by the attached diagrams, in which:

• Figures 1 to 4 are schematic views of a guide and unwinding device produced with known means; Figures 1 and 2 show it open for sewing the rib edges, respectively in section (fig. 1) and in profile (fig. 2). Figures 3 and 4 show it closed for the unwinding and sewing of the jersey, respectively in section (fig. 3) and in profile (fig. 4)
• Figures 5 to 8 are schematic views of an unwinding device according to the invention. Figures 5 and 6 show it open for sewing a ribbed edge, respectively from the front (fig. 5) and in profile (fig. 6). Figures 7 and 8 show it closed for unwinding and sewing the jersey, respectively from the front (fig. 7) and from the side (fig. 8).

Figures 1 and 2 show a known device for guiding and unwinding, in the open position for sewing the rib. The two slides (1) and (2) provide a slot (3) guiding the two joined ribbed edges (10) and (11) towards the cups (12) of the sewing machine. The two shoes (4) and (5) are separated at their base and are crossed by the pins (6) and (7) which are fixed and the ends of which are in contact with the blade separator (8), itself raised. Means not shown connect the blade lifting movement (8) to the opening of the shoes (4) and (5).

Figures (3) and (4) show the same known device in the closed position, during the unwinding and sewing of a jersey area. For this, the separating blade (8) is lowered into the slot (3) midway between the two slides (1) and (2) and a not shown mechanical device simultaneously authorized the closing of the shoes (4) and (5) which are brought together under the action of the spring (9) until it comes to compress the two selvedges of jersey (13) and (14) against the blade (8). In this position, the bowls (12) rotate and ensure the advancement of the knit throughout the device, the ramps (15) located at the rear of the shoes (4) and (5) unroll the edge of the jersey which slides flat between the shoes and the blade (8). The selvedges are forced to descend under the studs (6) and (7) whose position exactly determines the height of entry into the cups (12), and therefore the sewing height.

It is noted that in this known device, a fine seam in the jersey would require a low height "h" which would risk creating an obstacle when passing from the rib edge and the seam will necessarily be higher in the jersey than in the rib edge.

Furthermore, the action of the spring (9) creates a pressure and therefore a significant friction between the shoes (4) and (5), the blade (8) and the edges (13) and (14), this friction is still increased by the presence of a discontinuity in the form of the orifice created in the shoes (4) and (5) for the passage of the nipples (6) and (7) precisely where the pressure in the jersey is strongest .

Figures 5 and 6 schematically show a device, produced according to the invention, in the open position for sewing a rib.

Figure 5 is a front view, Figure 6 is a side view.

This device comprises, in known manner, two slides (18) and (19) guide to the bowls (35), a separating blade (20) which can pivot around an axis (27) for example by means of a jack (26) and two movable shoes (30) and (31) around horizontal axes respectively (32) and (33) and recalled by a spring (34). The mechanical connection making it possible to separate the shoes (30) and (31) when the blade (20) rises, has two oblique corners (21) and (22) integral with the blade (20) which separate two rollers (28) and (29) respectively integral with the shoes (30) and (31).

According to the invention, the two shoes (30) and (31) are not crossed by pins and do not have an orifice for this purpose. Two deflection plates (24) and (25) whose thickness is substantially equal to or very slightly greater than the thickness of the sewing jersey and the lower part of which has a generally rounded outline are integral with the blade (20) and pivot with it around the axis (27).

It is noted that in this open position the passage is perfectly cleared for the ribbing which can therefore be correctly guided between the blades (18) and (19) towards the cups (35) of the sewing machine thanks in particular to the absence nipples.

Figures 7 and 8 relate to the same device according to the invention shown this time in the closed position.

Figure 7 is a front view. Figure 8 is a side view.

When the end of the ribbing has passed at the level of the unwinding shoes, the jack (26) has commanded the simultaneous descent of the separating blade (20) between the slides (18) and (19) and of the two deflection plates ( 24) and (25) at an adjustable distance h ′ above the slides as well as the two corners (21) and (22) which have authorized the closing of the hooves.

Unlike the known devices shown in Figures 3 and 4, the shoes are no longer pressed directly against the jersey but are supported on the pads (24) and (25) whose thickness is substantially equal to or very slightly greater than that of the sewing jersey which can therefore slide with low friction in the device.

However, in the event that an additional thickness occurs, the latter can lift the hooves to clear a passage and the spring (34) would then fully resume its action. If this extra thickness is a non-absorbed roll, the increased pressure on the jersey will quickly absorb it until it returns to the previous situation with low friction.

Note that by adjusting the cylinder stroke you can independently adjust the low and high possibilities of the deflection plates, that is to say have h ′ as small as you want (fig. 7) without disturbing the edges ribs in open position (fig. 5).

The profile of the corners (21) and (22) and their position is designed to perfectly synchronize the descent of the blade and the closing of the shoes in order to avoid any loss of time and any asymmetry in the movement.

It is easily understood that the actuator can be automatic, for example by means of a photoelectric cell detecting the arrival of the side edge downstream of the device and located at a distance slightly less than the length of the side edge.

It is also conceivable that the deflection plates can be integral with the shoes (instead of the separating blade) and deviate with them to leave the field free for sewing the ribbing, without departing from the scope of the present invention.

Claims (7)

1. Device for the guidance and unwinding of selvedges for the sewing of knitted panels on bowl-type sewing machines, comprising:

- two slides (18, 19) spaced at a width substantially equal to the thickness of the panels to be joined together,

- a separator blade (20) capable of coming into place at the centre of the slides for the sewing of the jersey and of being raised out of the slides for the sewing of the rib ends,

- two unwinding shuttles (30, 31) located respectively on the right and on the left of the separator blade (20) and capable of being brought into contact with the fabric for the unwinding of the selvedges of the jersey and of being set apart for the sewing of the rib ends,

the device being characterized in that it comprises two deflector plates which are arranged between the separator blade and the unwinding shuttles and the thickness of which is approximate to the thickness of the jersey fabric and the lowest part of which is located at a distance from the slides which is adjustable as a function of the desired sewing fineness, the plates being raised at the same time as the separator blade during the sewing of the rib ends,

2. Device according to Claim 1, characterized in that the plates (24) (25) arranged between the separator blade (20) and the shuttles (30) (31) are fixed to the separator blade and are raised together with the latter for the sewing of the rib ends,

3. Device according to Claim 2, characterized in that the low position of the plates (24) (25) is adjustable in order to adjust the fineness of the sewing.

4. Device according to Claim 1, characterized in that the plates (24) (25) arranged between the separator blade (20) and the shuttles (30) (31) are fixed to the shuttles and can be set apart together with these for the sewing of the rib ends.

5. Device according to Claim 4, characterised in that the position of the plates (24) (25) is vertically adjustable.

6. Device according to any one of Claims 1 to 5, characterized in that a mechanical device (21) (22) synchronises the movements of rising of the separator blade (20) and of opening of the shuttles (30) (31).

7. Device according to Claim 6, characterized in that the mechanical opening and closing device (21) (22) is controlled automatically, for example by means of a photoelectric cell.

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