EP0260172B1 - Method and apparatus to retain piles of fabric before cutting - Google Patents

Description

The present invention relates to the preparation, with a view to their cutting, of mattresses of knitted textile panels, intended for making clothes such as pullovers, dresses or similar articles, as described for example in document GB-A 2 040 330.

The needle table is commonly used for the preparation of the constituent elements of a mesh article, for their assembly. The knitted panels are stretched and stacked on the needles, placed around the edge of the panel and at the remarkable points of the pattern. This positioning on needles makes it possible to put the panels under extension, and to maintain them in this state during cutting. In this way, each element of the article is cut from a knitted fabric whose mesh density is as homogeneous as possible.

However, the use of the needle table is not entirely satisfactory. Indeed, when cutting the mattress with an electric chisel, it is necessary to remove needles from the mattress as the chisel progresses through the mattress; this shrinkage causes deformation of the knitted fabric, in particular at the ribbing which tends to tighten strongly as soon as the needles are eliminated; a shift between the different layers of the mattress can also occur, in particular at the edge of the mattress when the cut is made at the edge: the scissor tends to drive out when there is five to ten millimeters of margin between the cutting line and the edge and the cut obtained is not regular.

To minimize these dissatisfactions, the knitting is generally placed on the needles under low extension, or even in the free state, although this is to the detriment of the quality of the preparation.

Now we have found, and this is what is the subject of the invention, an improvement in the preparation of mattresses on a needle table for cutting which makes it possible to remove these dissatisfactions. According to the method of the invention, the knitted panels are placed under extension on the needles of a needle table, the mattress consists of a sheet of air-impermeable material, a vacuum is created at the inside the mattress by suction of the air contained between the tablet and the sheet, the needles are removed from the mattress and the cutting is carried out while maintaining the suction throughout the duration of the cutting.

Unexpectedly, the depression created inside the mattress blocks the knitted panels in the state of extension in which they were placed during the constitution of the mattress throughout the duration of the cut. Vacuuming is also well known for cutting the mattresses of woven articles, which do not require extrusion of the corresponding panels, see for example FR-A 2 444 109. Thus in terms of mattress torque, there are two very distinct techniques depending on the articles: the needle technique for knitted panels and the vacuum technique for woven panels. It is the merit of the invention to combine these two techniques after it has been verified that the vacuum is sufficient to keep all the panels of the mattress in the extended state without removing the knitted fabric after releasing the needles. The needle technique is used for the preparation of the mattress, under extension; the vacuum technique for blocking the mattress. The combination of the two techniques according to the invention leads to a result which has not been obtained until now: the cutting of a mattress of knitted panels under extension free of needles.

It is another object of the invention to provide an improved needle table specially designed for the implementation of the above method. The needle table according to the invention comprises in known manner a vertically movable support on which the needles are fixed and a tablet perforated with holes in which the needles can slide. Typically, it comprises, under the lower surface of the tablet, a sealed box in which are placed the movable support and suction means capable of creating a vacuum in the box and through the holes formed in the tablet.

Preferably the needles are removable and maintained during their withdrawal from the mattress by temporary locking means. This particular arrangement has the advantage of being able to modify the number and the position of the needles when changing a mattress for example by removing certain needles, playing freely in the holes of the tablet, while allowing the withdrawal of the needles, then blocked. , by vertical displacement of the mobile support.

• . un profilé en U, fixé sur la face supérieure du support mobile de façon que la position de la génératrice extérieure du trou corresponde au flanc intérieur du profilé,
• . et un tube souple à paroi extensible, placé dans le fond du profilé, raccordé à une source d'air comprimé.

According to a preferred embodiment of the invention, the temporary blocking means of a needle comprise, placed under the corresponding hole formed in the tablet:

• . a U-shaped profile, fixed on the upper face of the movable support so that the position of the external generator of the hole corresponds to the internal side of the profile,
• . and a flexible tube with extensible wall, placed in the bottom of the profile, connected to a source of compressed air.

The needle, threaded into the hole, is received between the inner flank of the profile and the flexible tube. Temporary blockage of the needle is obtained by trapping the needle between said side of the profile and the wall of the inflated tube under the action of compressed air.

Advantageously, in line with the needle, the flexible tube is protected by a strip of a material having good resistance to friction, this in order to avoid deterioration of the wall of the tube during repeated introductions and withdrawals of the needle between the profile and the tube.

It is possible to implement other means for temporarily blocking the needles, however the preferred means above has proved to be simple to carry out and effective; it allows collective blocking of all needles with a single tube, or of portions of needles with a plurality of tubes.

• . une barre, fixée sur la face supérieure du support mobile,et un cylindre, solidaire du support mobile par les paliers maintenant son axe excentré, ladite barre et ledit cylindre étant parallèles et de part et d'autre de la génératrice extérieure du trou;
• . un levier, monté à l'extrémité de l'axe du cylindre, et relié à une tige actionnée par un vérin, de telle sorte que, lors de l'action du vérin, la tige entrai- nant le levier fait tourner I'axe du cylindre et, cet axe étant excentré, le cylindre pivote et applique l'aiguille contre la barre.

Mechanical means for blocking a needle will include, for example, placed under the corresponding hole formed in the shelf:

• . a bar, fixed on the upper face of the mobile support, and a cylinder, integral with the mobile support by the bearings maintaining its eccentric axis, said bar and said cylinder being parallel and on either side of the external generatrix of the hole;
• . a lever, mounted at the end of the cylinder axis, and connected to a rod actuated by a jack, so that, during the actuation of the jack, the rod driving the lever turns the axis of the cylinder and, this axis being eccentric, the cylinder pivots and applies the needle against the bar.

The invention will be better understood on reading the description which will be given of an exemplary embodiment with reference to the appended drawing in which:

• La figure 2 montre le même panneau fixé sur la table à aiguilles en vue de la coupe.
• La figure 3 est une vue schématique en coupe de la table à aiguilles selon l'invention.
• La figure 4 est une vue schématique de dessus de la table à aiguille.
• Les figures 5a, 5b et 5c sont des vues schématiques en coupe du moyen de blocage pneumatique, sans aiguille (5a), avec aiguille non bloquée (5b), avec aiguille bloquée (5c).
• La figure 6 est une vue schématique en coupe d'un moyen de blocage mécanique.

Figure 1 shows a knitted panel falling from loom

• Figure 2 shows the same panel attached to the needle table for cutting.
• Figure 3 is a schematic sectional view of the needle table according to the invention.
• Figure 4 is a schematic top view of the needle table.
• Figures 5a, 5b and 5c are schematic sectional views of the pneumatic locking means, without needle (5a), with unblocked needle (5b), with blocked needle (5c).
• Figure 6 is a schematic sectional view of a mechanical locking means.

We will take as an example a knitting panel 1, falling from a straight loom, the base of which has an ribbing 2. The intertwining of the threads used to produce this ribbing has the effect of tightening the base of the panel. The knitting is carried out so that over the width of the panel there are obtained several elements of the article to be made, the number of said elements varies according to the models and sizes (in the case illustrated in FIG. 1 it is three backs ).

The panel 1 is stretched and fixed on the shelf 3 of the needle table 4 by means of the needles 5 placed on the periphery of the panel 1 and at the remarkable points of the pattern. Several panels are placed one on the other and constitute a mattress 6.

The needle table 4 comprises the shelf 3, the mobile support 7 and the suction box 8. The shelf 3 is perforated with holes 9 regularly spaced according to the grid which is illustrated in FIG. 4. The interval between each hole is of the order of 2 centimeters. Each hole 9 has a diameter sufficient to allow the free sliding of a needle 5.

The movable support 7 comprises a plate 10 on which are fixed the U-shaped sections 11 intended for blocking the needles 5, and the means ensuring the vertical movement of the plate 10. These means consist of an endless screw 12 secured to the frame 13 of the table 4, and driven in rotation by the motor 14. Two nuts 15 blocked by caps 16 are mounted at the ends of the screw 12; they are fixed to the lower end of the arm 17 articulated around the axis 18. The upper end of this arm 17 carries a roller 19 rolling in the slide 20. The plate 10 is guided transversely and longitudinally in the frame 13 by the casters 21.

The profiles 11 are fixed on the plate 10 so that the external generator 9 'of a hole 9 corresponds to the internal flank 11' of a profile 11. As illustrated in FIG. 5, the same profile is placed under two adjacent holes , which allows the locking of two needles simultaneously.

The flexible tube 22 is placed inside the profile 11. One end of this tube 22 is closed while the other is connected to a supply of compressed air. The wall 23 of the tube 22 is extensible. A protective strip 24, folded in the shape of a U in the lengthwise direction, is pinched between the tube 22 and the profile 11. This strip 24 is an element of a flat belt. There are as many profiles 11 on the plate 10 as there are lines of holes (Figure 4). A strap 25 is stretched transversely above the profiles 11, at the rate of a strap every twenty centimeters, by means of hooks fixed on the plate 10 between each profile. The ends of each strap 25 are pinched under the end sections. The width of the strap 25 is such that it can pass between two lines of needles.

The suction box 8 consists of walls laterally closing the four sides of the frame 13, the bottom 26 and the shelf 3, all forming a sealed box in which are locked the movable support 4 and the needle locking means. The turbine 27, fixed to the bottom 26, creates a vacuum inside the box 8.

The operation of the table 4 for the preparation of the mattress for cutting is carried out as follows. The movable plate 10 being in the high position, needles 5 in a determined number are placed in the holes 9 of the shelf 3 according to the appropriate arrangement as a function of the size of the panels and the conformation of the pattern. Each needle 5 is introduced into the housing between the section 11 and the outer wall of the ruba 24 which protects the tube 22. The compressed air is sent into all the tubes 22, which increases the diameter of said tube (fig. 5b and 5c) which clamps the needle 5 against the inner flank 11 'of the profile. All the needles 5 are thus blocked simultaneously. The role of the band 24 and the strap 25 is to hold the tube 22 in the profile 11 and to prevent it from deforming and being damaged by the passage of the needles 5.

The motor 14 is started so that the nuts 15 move on the worm 12 towards the edges of the frame 13, driving down the lever 17 which, associated with the movement of the roller 19 in the slide 20, makes lower the plate 10. The engine is stopped while the needles 5 protrude two to three centimeters above the tablet 3. The operator can then start the padding, fixing under extension in accordance with Figure 2 each panel 1 on the needles 5. During quilting, when the needle height is no longer sufficient, the rise of the plate 10 is controlled by a new rotation of the motor 14 in the opposite direction.

When the mattress 6 is finished, it is covered with a plastic wire 28, airtight, so that it overflows beyond and on each side of the mat las 6. The suction turbine 27 is started. The depression created in the sealed box 8 propagates through the holes 9 in the enclosure formed by the space between the film 28 and the tablet 3. This depression presses the film 28 onto the mattress 6 and compresses the latter.

The motor 14 is activated in the opposite direction, which lowers the plate 10 and, the needles 5 being blocked between the profiles 11 and the tube 22, which retracts the needles 5. The cutting can then begin, the turbine 27 being kept in operation for the duration of the cut. Thus the mattress is compressed and held in extension under the effect of the suction, and can be cut in the absence of needles.

When the cut is complete, the turbine 27 is stopped and the logs of cut pieces (for example along the dotted lines in FIG. 2) are removed. Table 4 is available to start a new cycle.

If the placement of the needles 5 must be modified or changed completely, it suffices to reassemble the movable plate 10 and to unlock the needles 5 by cutting the compressed air in the tubes 22.

The preferred embodiment which has just been described is not limitative of the invention. In particular, other means for blocking the needles can be used. FIG. 6 illustrates a blocking system by purely mechanical means. A bar 29 and a cylinder 30 are fixed on the plate 10 parallel to and on either side of each line of needles. The bar is fixed to the upper face of the plate 10 and the cylinder 30 is secured to the plate 10 by two bearings holding the ends of its axis 31 of rotation, this axis 31 being eccentric. At the end of the axis 31 is mounted a lever 32 which is itself connected to a rod 33. This rod 33 is unique for all the cylinders; it is actuated by a jack 34. The operation is as follows. In the normal position corresponding to the threading of the needles (FIG. 6) the bar 29 and the corresponding cylinder 30 are spaced apart from each other leaving between them a space intended to receive the lower part of the needle 5. To make the blocking, the jack is actuated, the rod 33 moves in the direction of arrow F, the lever 32 rotates the axis 31 on itself, which causes the cylinder 30 to pivot, which, the axis 31 being eccentric, presses against the needle, wedged between the cylinder 30 and the bar 29.

For a tablet whose surface with perforations is 100 cm / 200, the depression implemented by the turbine was 300 mm of water at a flow rate of 300 m3 / h. The tablet has 5151 perforations of 2 mm in diameter.

Claims (5)

1. A method of preparing a multilayer web of knitted textile pieces (1) for cutting, of the kind in which the knitted pieces (1) are stretched on the needles (5) of a needle table (4), characterised in that:

- The resulting multilayer web (6) is covered with a sheet (28) of an airtight material, a negative pressure is produced inside the web (6) by sucking air from between a level top (3) and the sheet (28), the needles (5) are withdrawn from the web (6), and the web is cut while mainteining suction during the entire cutting operation.

2. A needle table for working the method according to claim 1, of the kind comprising a vertically movable holder (7) to which the needles (5) are secured and a level top (3) perforated with holes (9) in which the needles (5) can slide, characterised in that a sealingtight box (8) is disposed under the lower surface of the level top (3) and contains the movable holder (7) and suction means (27) capable of producing a negative pressure in the box (8) and through the holes (9) formed in the level top (3).

3. A needle table according to claim 2, characterised in that the needles (5) are removable and held by temporary securing means (11, 22; 29, 30) while being withdrawn from the web (6).

4. A needle table according to claim 3, characterised in that the means for temporarily securing a needle (5) comprise the following, placed under the corresponding hole (9) formed in the level top (3): A U-section member (11) secured to the top surface of the movable holder (7) so that the position of the outer generatrix (9') of the hole (9) corresponds to the inner surface (11') of the section member (11), and A flexible tube (22) having a stretchable wall (23) and disposed at the bottom of the section member (11) and connected to a compressed air source.

5. A needle table according to claim 3, characterised in that the means for temporarily securing a needle (5) comprise the following, disposed under the corresponding hole (9) formed in the level top (3):

A bar (29) secured to the top surface of the movable holder (7) and

A cylinder (30) secured to the moving holder (7) by bearings which keep its axis (31) out of centre, the bar (29) and the cylinder (30) being parallel to and on either side of the outer generatrix of the hole (9), and a lever (32) mounted at the end of the axis (31) of the cylinder (30) and connected to a rod (33) actuated by a jack (34) so that, when the jack (34) is in operation, the rod (33) pulling the lever (32) rotates the cylinder axis (31) and, since the axis (31) is eccentric, the cylinder (30) pivots and presses the needle (5) against the bar (29).

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