EP0521066B1 - Process and device for separating piled textile cut-outs - Google Patents

Abstract

The invention proposes a process and a device for ensuring reliable separation of cut-outs and layers of material in a pile of cut-outs (3) into individual cut-outs (7). Before the gripped cut-out (7) is separated, a loading device (20) is placed on the surface of the uppermost, lifted cut-out (7), causing it to sag, and during the application of pressure a holding down device (21) is introduced into the gap (25) formed between the uppermost (7) cut-out and the redundant cut-out (7'). The corresponding device has a loading device (20) which moves freely in relation to the gripper elements (10, 11, 12 ...), in particular needle grippers (13), and which can be lowered onto the surface of the gripped cut-out (7) to a level below the gripping plane of the needles (13) in order to form a sag downwards and, in particular, to partially envelop a blowing tube (20a).

Description

The invention relates to a method for separating stacked textile blanks with the generic features of claim 1, and an apparatus for performing this method.

Such a method and a corresponding device is known from DE-OS 37 19 393, air nozzles being arranged between the gripper elements, by means of which the further material parts adhering to them when a blank is gripped are to be removed by a corresponding air flow or air blast. This is intended to separate the uppermost blank on a stack of blanks from the other adhering fabric parts, which stick to the first gripped blank, in particular by interlocking fibers.

This separation problem represents a bottleneck, particularly in automation in the clothing industry, since reliable separation of the fabric stack into individual cuts has not hitherto been able to be reliably solved. The textiles are cut in a pile in a plurality of layers of fabric at the same time in accordance with the pattern provided, so that the stack has to be broken down into its individual blanks for the subsequent operations, for example sewing, etc. In addition to the interlocking of fibers, there are in particular hooks on the cut edges created during cutting, so that very high, but fluctuating, adhesive forces are present between the individual cuts.

According to DE-OS 37 19 393, the excess blanks are to be blown off from the topmost textile blank to be gripped. In this case, the gripping element is preferably formed by a so-called solid freeze gripper, the topmost adhering to it by partial icing of the blank Cutting is achieved. Excess blanks are to be removed by air nozzles, the outlet opening of which is arranged approximately in the plane of the gripping elements. Here, however, it can happen that the uppermost blank is blown off by the gripping elements when operating the blowing nozzles, since an air cushion forms between the flat gripping elements and the gripped fabric layers, which partially or completely detaches the gripped cuts from the gripper. Even if adhesive grippers or needle grippers with higher gripping forces were used instead of the freezer gripper, this disadvantageous effect was shown, so that the top cut from the remaining stack could not be reliably detached.

Particularly when so-called hold-down devices were used as separation and separation aids, which are intended to maintain the order of this remaining stack when the uppermost blank is removed from the rest of the stack, a further disadvantage occurred that the uppermost blank, which is acted upon by the air flow, is pressed down below the engagement level of the hold-down device could, so that this was also held by the hold-down. This made stripping the top blank impossible. Overall, no constant, reproducible separation could be achieved with this device. These disadvantages also apply to the further known separating devices according to DE-OS 20 21 233 and DE-OS 31 47 818, since in this case a hold-down device is placed on the stack of blanks and the fiber entanglements are therefore reinforced even more. The same applies to the separating devices according to US Pat. No. 4,283,047 and US Pat. No. 3,275,317, in which the central region of the uppermost blank is pressed onto the stack by a needle or a plate during the separating process and the negative fiber entanglements are thus further increased.

EP-A-0 086 280 describes a separating device for paper bags, the center of each paper bag being lifted with a spring-loaded, piston-like one Load device is pushed down while the edges of suction cups are gripped. In the case of strongly adhering blanks, as can be the case with textile blanks, in particular with hooks on the cut edges, this would not ensure isolation.

EP-A-0 165 019 describes the use of compressed air for separating textile blanks, but this is done before or during the lifting of the top blank. Here, however, the compressed air can escape laterally, so that its detaching effect cannot be used.

Accordingly, the object of the invention is to provide a method and a device for separating stacked textile blanks with which a reliable detachment of adhering further material parts from the top blank and thus a safe separation is made possible.

This object is achieved by a method with the features of claim 1 and by a device with the features of claim 2.

By placing the loading device directly on the surface of the gripped blank when it is lifted from the stack, a curvature downwards and thus a tensioning of the blanks is achieved, which is sufficient to generate shear forces between the uppermost, decreasing and excess blanks and thus one, albeit one to form a small gap into which the opposite hold-down device can be inserted. This loosening or gap formation is increased, in particular, by applying pressure by means of an air stream or air blast directly through the uppermost textile blank to the blanks which may adhere underneath. Since the uppermost blank is in direct contact with the loading device, in particular a blowpipe and virtually envelops it, the outflowing air can no longer dodge between the gripping element and the surface of the uppermost blank and thus detach it from the gripping elements. By placing the loading device directly on the surface of the raised blank, the blank is clamped and arched downward, so that the pores of the textile are expanded and thus a higher air permeability for the air flow is achieved. Evasion and misdirection of the air flow are practically excluded. This effect can be improved if the loading device is placed under an additional pretension.

Due to the direct introduction of air into the uppermost blank, a spatially precisely defined gap is formed between the uppermost and the possibly adhering second or third blanks, into which a hold-down device can be securely inserted to hold the remaining stack, since the air cushion between the first and second Cut forms a kind of tunnel in which the hold-down can engage without contact with the cuts. With this method, a reliable separation and lifting of the top blank is achieved, even if several blanks should be gripped by a needle gripper in the case of thin materials lying on the stack of blanks with a wavy surface.

The device according to the invention for separating stacked textile blanks is characterized in that the loading device is no longer rigidly connected to the gripping elements compared to the known solution, but is arranged such that it can be moved vertically and directly onto the surface of the gripped top blank below the horizontal plane of the Needles or the lower edge of the gripping elements can be lowered. This relative mobility, in the sense of a kinematic reversal, also includes that the loading device is rigidly arranged and the gripper together with the gripped blank (s) can be moved upwards against the loading device in order to achieve the desired arching of the blanks to generate in the raised state. A combination between the relative mobility is also possible. It is essential here that tension and arching of the gripped blanks is achieved in the area of the loading device.

In order to increase the tensioning of the blanks and the encasing of the loading device described above, the loading device is lowered in the form of a so-called blow tube under the pretension of a spring element onto the top blank, so that there are constant blowing conditions in each case. In general, however, the weight of the loading device is already sufficient for a secure support and thus contact during the blowing process in order to prevent misdirection of the air flow.

In the simplest version, the loading device is telescopically mounted in the gripping element, so that after the uppermost blank has been gripped, the blow-out opening can be lowered below the gripping level (needle level) in order to obtain the bracing described above in the top blank.

Instead of the translational mobility of the loading device, however, it can also be mounted on a swivel bracket, the swivel bracket in the preferred embodiment of the blowpipe also serving for the compressed air supply.

It is essential that the same engagement position of the hold-down device is achieved, in particular if a stop is provided for the vertically movable loading device, so that the gripped top fabric layer is pressed down by the same amount under the gripping element and thus the hold-down device is at a constant distance from the gripping element between can reach for the top cut and excess fabric parts. On the other hand, the detection of the swivel angle or, in the translational solution, the lowering path, the sag of the top blank are detected and the entry height of the hold-down device can be controlled accordingly.

Furthermore, the detection of the swivel angle or the lowering path of the loading device can be used to control the contact force of the loading device on the uppermost cut, in order to prevent overloading by the contact force when changing different fabric layers.

Of particular importance is the common mounting of the loading device and the hold-down device, regardless of the gripping elements, since this maintains the positional relationship between the loading device, in particular the lower edge of the blowpipe and the upper hold-down device, so that the hold-down position is defined after the blowpipe is placed on it.

Fig. 1

eine Seitenansicht einer Greifeinheit über einem Zuschnittstapel;

Fig. 2

eine perspektivische Darstellung der Greifeinheit gemäß Fig. 1;

Fig. 3

eine vergrößerte Darstellung der Greifeinheit mit einem gegriffenen obersten Zuschnitt;

Fig. 4

eine zweite Ausführungsform einer Greifeinheit mit einem Schwenkbügel;

Fig. 5

eine Draufsicht auf eine Greifeinheit gemäß Fig. 4,

Fig. 6

eine Schnittdarstellung gemäß der Linie A-A in Fig. 5.

Further advantageous embodiments are the subject of the subclaims and are explained and described below with reference to two exemplary embodiments in the drawing. Show it:

Fig. 1

a side view of a gripping unit over a blank stack;

Fig. 2

a perspective view of the gripping unit of FIG. 1;

Fig. 3

an enlarged view of the gripping unit with a gripped top blank;

Fig. 4

a second embodiment of a gripping unit with a swivel bracket;

Fig. 5

4 shows a plan view of a gripping unit according to FIG. 4,

Fig. 6

5 shows a sectional illustration along the line AA in FIG. 5.

In the figures 1 and 2, a gripping unit 1 is shown in its basic structure. The gripping unit 1 is placed with a base plate 2 on a stack 3 of blanks 7 that are identical to one another, but is not yet in engagement connection with the individual blanks. In this embodiment, the gripping unit 1 is loaded with its Dead weight on the stack 3, with support rods 8 engaging in an upper frame part 5, which is connected to the base plate 2 via vertical supports 4. The support rods 8 can be connected to a lifting frame or a handling device such as a robot. When lifting the support rods 8, the frame 5 and the entire gripping unit 1 are also lifted. The structure of the gripping unit 1 is further described in more detail in the unpublished DE-OS 39 14 194 by the same applicant and is not essential for the present invention.

The blanks 7 of the stack 3 can be woven, knitted, knitted or other textile blanks. The blanks 7, for example for articles of clothing, are lifted one after the other from the stack 3 by the gripping unit 1. The carriers 4 are connected by a bearing plate 6, in the center of which an actuating device 9 is provided for a plurality of gripping elements 10, 11 and 12, which are shown in detail in FIG. 2. The gripping elements 10, 11 and 12 can be spread apart in openings in the base plate 2 in the horizontal plane, hook-shaped needles 13 provided on the underside penetrating into the uppermost blank 7 of the stack 3.

To actuate the gripping unit 1, a plurality of bearing eyes 14 are provided on the upper side of the gripping elements 10, 11 and 12 and are connected in parallelogram form to the bearing plate 6 by means of levers 15. The inner levers 15 are designed as two-armed levers and are each connected to a further pivot lever 16, which are connected to a bearing head 17 of the actuating device 9. The actuating device 9 can be formed, for example, by a pneumatic cylinder which is moved upward when loaded into the position shown in dash-dotted lines, so that the pivot levers 16 and the levers 15 are stretched and thus the gripping elements 10, 11 and 12 are spread apart (cf. position in Fig. 3). So that the needles 13 pierce obliquely outwards and downwards in the top cut 7 of the stack 3 in each case. The penetration depth of the needles 13 in the uppermost blank 7 can be adjusted by different upward strokes of the actuating device 9. After the needles 13 have engaged, the gripping unit 1 is lifted from the stack 3, for example by lifting the support rods 8, or is tilted upwards, so that at least the uppermost blank 7 is slightly lifted from the stack 3 by the amount x (see FIG. 3 ) and can be fed to further processing stations after the blowing process.

2, the gripping elements 10, 11 and 12 are shown in perspective. From this it can be seen that when the actuating cylinder 9 and the associated lever gear 15, 16 are actuated, the gripping elements 10, 11 and 12 are spread apart in a horizontal plane, as a result of which the needles 13 penetrate into the uppermost blank 7. However, it should be pointed out that this type of needle gripper can also be replaced by an adhesive gripper or by a so-called freeze gripper or other gripping devices known to the person skilled in the art.

It is now essential that a loading device 20 is provided in the area of at least one gripping element, which is indicated here between the gripping elements 10 and 11. It is important here that the loading device 20 is arranged to be freely movable vertically relative to the gripping elements 10 and 11 and, after being raised by the amount x onto the surface of the gripped blank 7, can be lowered independently of the height position of the gripping element 10, 11 and the blanks 7, 7 'braced. It is also important that a hold-down device 21 is arranged opposite the loading device 20 (cf. also FIG. 4), which can engage after the loading device 20 has been placed below the top gripped blank 7.

The step of putting on the loading device 20 is shown in FIG. 3, the view from that in FIG Fig. 2 upper edge, in the vicinity of which the hold-down 21 is arranged, according to the arrow B from. The gripping elements 10 and 11 have detected a top blank 7, but a further, redundant blank 7 'adheres. The loading device 20, here in the form of a preferred blowpipe 20a, which is connected to a compressed air line 22, is mounted here on the bearing plate 6 (cf. FIG. 1) and is freely movable in the vertical direction. After lifting the gripping unit 1 by the amount x of a few centimeters after gripping at least one blank 7, the loading device 20 moves downward due to its own weight and loads the top blank 7, so that in the prestressed state it sags slightly, but from the needles Gripping elements 10 and 11 is still held securely. The preload on the top blank 7 can be increased by a spring-loaded loading device 20. A pneumatic cylinder can also be connected to the loading device 20 by mounting in the bearing plate 6, which presses the loading device 20 down onto the blank 7 with a defined force. As a result, the blanks 7 and 7 'are arched downwards and thus a shear force is generated between these two layers of material, which brings about loosening and loosening of the adhesive forces in the region of the largest arching and thus creates a slight gap 25. On the other hand, the top blank 7 is thus always pressed into the same height position, so that the hold-down device 21 can retract exactly laterally at this height position. The distance between the lower edge of the loading device 20, z. B. a simple flat bar and top edge of the hold-down 21 can be adjusted exactly to the thickness of the fabric (or a multiple, e.g. when gripping two layers of fabric).

The loading device 20 is designed as a blowpipe 20a, after its placement, an air stream flows through the compressed air line 22 through the outflow opening 23 and through the top blank 7 down to the further excess blank 7 '.

Since, in contrast to the prior art, the loading device 20 in the form of the blowpipe 20a rests firmly on the blank 7 due to its own weight of the prestressing and is surrounded by the uppermost blank 7 in the vicinity of the outflow opening 23 and is not spaced apart, the compressed air supplied cannot follow emerge outside between the gripping elements 10 and 11 and the top blank 7. Rather, the compressed air takes the path of least resistance, which lies here in the region of the blank 7 which is pressed down and thereby biased. Characterized a dotted air cushion 24 is generated between the top blank 7 and the extra blank 7 'and thereby the gap 25 already formed by the support, tension and arching between the top blank 7 and the extra blank 7' widened. This gap 25 is formed in a tunnel shape due to the opposite arrangement of the loading device 20 to the side edge to the hold-down device 21 (see FIG. 5, dotted area), so that the hold-down device 21 can be securely inserted into the gap 25. Even if the pressurization by the loading device 20 has not yet led to the complete detachment of the excess blank 7 ', the excess blank 7' is now held by the hold-down device 21 on the remaining stack 3, so that the subsequent lifting of the gripping unit 1 with the gripping elements 10, 11 only the top blank 7 is conveyed on.

4 and 5 show a second embodiment of the gripping unit 1 with four gripping elements 10, 11, 12 and 12a in a side view and a top view. Instead of the translationally movable loading device 20, it is mounted here in a freely movable manner in the vertical direction in the region of the gripping elements on a swivel bracket 26. The swivel bracket 26 also accommodates the compressed air line 22 which leads to the tubular loading device 20 which is pressurized with compressed air here. The blowpipe 20a With the outlet openings 23 directed towards the stack 3, it engages in a cutout 2a in the base plate 2 and in the gripping element 10 and is freely movable in this cutout about the pivot axis 27 of the swivel bracket 26 approximately by a swivel angle of 10 °. When the gripping elements are placed on the blank stack 3, the blow tube 20a is located above the needles 13 and then lowers during the lifting of the top blank (s) 7, 7 'or preferably shortly thereafter by the amount x onto the surface of the topmost Cutting 7 by the dead weight until a stop 28 hits the base plate 2. This forms the trough-shaped sag of the blank (s) 7, which is essential to the invention and is shown in FIG. 3.

The lowest possible position of the blowpipe 20a is indicated in FIG. 4, from which, depending on the material, a sag of several millimeters to centimeters can result compared to the majority of the top blank 7 adhering to the needles 13, as is shown in FIG. 3. To reinforce the pre-tension of the gripped top blank 7, the swivel bracket 26 can be lowered by an actuating device, for example a pneumatic cylinder (not shown in more detail) to the limit by the stop 28. The blow-down tube 20 is adjacent to the hold-down device 21, which can be lowered in the vertical direction in accordance with the setting of the stop 28 by a few millimeters below the lower edge of the blow tube 20a and after the blowing process can be moved laterally into the gap 25 shown in FIG. The hold-down 21 has a shape that is as flat as possible. It should be pointed out that a single hold-down device 21 is sufficient for reliable operation, but several can also be provided.

5, the cloverleaf-shaped arrangement of the gripping elements 10, 11, 12 and 12a can be seen in plan view, which has correspondingly shaped openings in the base plate 2 intervention. At the edge of the openings for stripping the gripped blank 7 when retracting the gripping elements by horizontal and vertical lines wires, for. B. piano strings 29 indicated, on which the top blank 7 is stripped when lifting the gripping elements due to the lowering of the actuating cylinder 9 (see FIGS. 1 and 4).

On the swivel axis 27 of the swivel bracket 26, when the uppermost blank 7 is pretensioned, a resolver 30 can be provided only on account of the weight of the loading device 20, which, depending on the elasticity and thus the size of the sag (see FIG. 3), determines the height position of the blowpipe 20a and accordingly controls the height position of the hold-down 21 in the Z direction. The height position of the upper edge of the hold-down 21 corresponds to the lower edge of the blow tube 20a minus the respective fabric thickness of the blank 7 to be gripped, so that the hold-down 21 can be raised or lowered along the Z-axis and then in the Y-direction between the top two blanks 7 and 7 'is retracted.

Instead of detecting the Z position of the loading device 20 and the corresponding control of the hold-down device 21 (plus the respective fabric thickness), these two components 20, 21 can be mounted on a common carrier 31 and moved together independently of the gripper 1, as shown in FIG. 4 dashed and is shown enlarged in Fig. 6. It is thereby achieved that the lower edge of the loading device 20 and the upper edge of the hold-down device 21 have a constant distance in the Z direction, which is adjusted to the respectively processed fabric thickness.

6 shows the section along the line AA in FIG. 5, but the loading device 20 in the form of the blow tube 20a is not mounted on the swivel bracket 26 but on the carrier 31 together with the hold-down device 21. After the attachment shown here ( in the Z direction) of the loading device 20 on the uppermost, gripped blank 7, bracing and arching of the blanks 7, 7 ' Compressed air is turned on to widen the gap 25, which flows out of the obliquely positioned blow-out opening 23 towards the side edge. The hold-down device 21 is now moved laterally into the gap 25 along the Y axis, the blow tube 20a being able to remain in the position shown or can also be moved in the Y direction towards the center of the gripper 1. The latter alternative results in a tunnel-shaped configuration of the air cushion 24, the configuration of which can also be supported by a further blow-out opening 34 at the tip of the hold-down device 21. A similar effect is achieved by a groove 33, also shown in FIG. 5, on the upper side of the hold-down device 21, through which the compressed air emerging from the blow-out opening 23 is increasingly deflected inward as the hold-down device 21 approaches during the retraction along the Y axis. These versions are particularly useful for separating large blanks.

Claims (10)

1. A process for separating piled textile cut-outs, comprising the following steps:

   - gripping the respective topmost cut-out (7) by several gripping elements (10, 11, 12, ...),

   - lifting said respective topmost cut-out (7) at least at one edge thereof, and

   - loading excess cut-outs (7′) possibly clinging thereto by a loading device (20),
   characterized in that
   first, said loading device (20) is put onto the surface of said topmost lifted cut-out (7) in the area of a gripping element (10, 11, 12), then, said cut-out (7) lifted off the pile (3) is braced and cambered downward at one edge thereof in the area of said loading device (20), and during the loading by pressurized air a downholder (21) opposing said loading device (20) is moved into the gap (25) growing between said topmost and said excess cut-out (7, 7′).
2. A device for performing the process of claim 1, comprising several gripping elements (10, 11, 12, ...) and a loading device (20) for loading a lifted cut-out (7),
   characterized in that
   said loading device (20) provided in the area of a gripping element (10, 11, 12) is formed as a blow pipe (20a) comprising a pressure duct (22) associated thereto and at least one blast opening (23), is arranged vertically-slidable with respect to said gripping elements (10, 11, 12, ...) and can be lowered as far as below the gripping plane of said gripping elements (10, 11, 12, ...) to the surface of the gripped cut-out (7), and said loading device (20), in its separating position, has arranged a downholder (21) opposite thereto.
3. The device of claim 2, characterized in that said loading device (20) can be lowered to the topmost cut-out (7) by biasing a spring element.
4. The device of claim 2, characterized in that said loading device (20) can be lowered as far as to a backstop (28) by biasing a working cylinder.
5. The device of any of claims 2 to 4, characterized in that said loading device (20) is mounted telescopically movable downward onto the topmost cut-out (7).
6. The device of any of claims 2 to 4, characterized in that said loading device (20) is mounted at a pivoting bar (26).
7. The device at least of claim 2, characterized in that the altitude level of said loading device (20) is detected by a position sensor (30) and the altitude level (z) of said downholder (21) is correspondingly controlled.
8. The device at least of claim 2, characterized in that said loading device (20) and said downholder (21) are arranged at a common support (31) and are vertically-slidable together and independent from said gripping elements (10, 11, 12, ...), the distance between the bottom edge of said loading device (20) and the top edge of said downholder (21) being adjustable to the respective cloth thickness.
9. The device at least of claim 2, characterized in that the upper side of said downholder (21) is provided with a groove (33) open in the direction of the center of the gripping device (1) and opposing said blow pipe (20a) during loading.
10. The device at least of claim 2, characterized in that the front end of said downholder (21) is provided with a further blast opening (34).

Images