EP0552349B1 - Process and device for forming three-dimensional covers - Google Patents

Abstract

PCT No. PCT/EP92/01836 Sec. 371 Date Apr. 12, 1993 Sec. 102(e) Date Apr. 12, 1993 PCT Filed Aug. 11, 1992 PCT Pub. No. WO93/04228 PCT Pub. Date Mar. 4, 1993.For forming three-dimensional envelopes of at least two blanks (11, 13) which are to be sewn together, the first blank (11) is laid on a first support surface of a carrier body (14) in such a manner that its edge portion projects beyond the carrier body. Thereafter, a second blank (13) is laid on a second support surface of the carrier body (14), the edge portions (11a, 13a) of both blanks projecting obliquely from the blanks and forming a double flange portion projecting from the carrier body (14). A sewing machine is guided along the root line (57) formed by the kink lines of the edge portions (11a, 13a) so that a seam interconnecting the blanks (11, 13) is created there.

Description

The invention relates to a method for forming three-dimensional envelopes from blanks according to the preamble of patent claim 1 and a device for carrying out the method according to the preamble of patent claim 4.

Usually, three-dimensional sleeves that are sewn are produced by laying the blanks to be sewn flat in a sewing machine and passing them under the sewing foot of the sewing machine in a flat state. The edges of the blanks are provided with markings that have to be placed on top of each other. This type of sewing requires a high level of skill. Nevertheless, it is unavoidable that the blanks move against one another during sewing, which results in wave formation and gathering in the casing to be produced.

The performance possibilities of the sewing machine are not used by the relatively slow manual control.

DE 33 38 405 A1 discloses a method for producing three-dimensional casings with seams, in which blanks are attached to a three-dimensional support body and a sewing machine attached to a manipulator arm is moved along the intended seam line. The edges of the blanks are superimposed flat on the carrier body and the needle of the sewing machine is inserted through the edges into the carrier body. This requires the insertion of a loop catcher to create the seam inside the carrier body.

In another method known from EP 0 344 400 A1 for sewing a sleeve into a jacket, the sleeve is inserted into the turned jacket so that the edge of the sleeve opening is placed from the inside against the edge of the jacket opening (armhole). For sewing, a sewing machine is guided around the edges lying together, the stitch plate with the loop catcher underneath it being inserted into the opening. The problem arises here that the outer edge and the inner edge enclosed by it have different diameters during the sewing process, so that these edges are subjected to a constraint when they are in one another.

DE-A-1660 811 discloses a method for forming three-dimensional envelopes from a plurality of blanks which are sewn at their mutually opposing edges by means of a mower, the blanks being applied to a carrier body which has mutually mutually abutting contact surfaces.

The invention is based on the object of specifying a method and a device for forming three-dimensional envelopes which, irrespective of the accuracy of the blanks to be sewn, enable the envelope to be produced with a precise shape.

This object is achieved according to the invention with the features specified in claim 1 or in claim 5.

In the (not prepublished) patent application P 41 02 840, a method is described in which the mowing is generated at the root of the edge struts.

In the method according to the invention, the two blanks are placed on the carrier body in such a way that their edges abut against one another and form an outwardly projecting edge strip. The blanks positioned in this way on the carrier body are sewn along their edges lying at an angle and protruding from the carrier body with at least one sewing machine which creates the seam along the root line. In this way, it is not only possible to position the blanks to be sewn quickly and precisely, but also to produce the seam precisely and free of folds and distortions.

The edges of the blanks protrude obliquely from the two contact surfaces, ie they form an angle with each of the contact surfaces that is greater than 0 ° and less than 90 °, preferably 45 °. The intended seam line, along which the needle of the sewing machine is guided, runs exactly along the root line of the edge strip formed by the mutually opposite edges of the blanks, that is to say along the fold lines of the edges of the blanks. The workpiece produced in this way can then be turned over so that it forms the edge strip adjacent edges of the blanks lie inside the workpiece. When producing three-dimensional envelopes from flat blanks, there are different lengths in the seam area for the seam lines on the outer and inner blanks. In the method according to the invention, both blanks are shaped against one another in such a way that this difference in length arises in a relaxed manner. Any inaccuracies in the manufacture of the blanks or their subsequent dimensional changes do not affect the end product.

According to claim 2, the application of the blanks to the carrier body, the sewing and the removal of the sleeves from the carrier body each take place in a different position of the carrier body, the carrier body being moved from one position to the next. This has the advantage of a division of the individual work steps suitable for industrial mass production, as well as the advantage that the individual work steps can be carried out simultaneously using several carrier bodies.

The device according to the invention has the features of claim 4. In this device, the at least two blanks to be sewn together are placed on the contact surfaces of the carrier body and the sewing machine is guided in such a way that the seam is produced along the root line, in which the first and the second contact surface abut one another.

In a preferred embodiment according to claims 5 and 6, the first blank is clamped in the first application device between a holding plate and a frame. The holding plate forms the blank according to the later shape of this blank on the casing and the frame serves to bend the edge of the blank, so that the usable area of the blank and the edge are already shaped and defined in the holding device. There is a gap between the frame and the holding plate which is adapted to the material thickness of the blank.

According to claim 7 it is provided that the holding plate remains on the carrier body while the frame is removed from the carrier body. This has the advantage that the fixation of the first blank to the carrier body is maintained during sewing. The holding plate can be held in place by magnets, by a suction device in the carrier body or in the holding plate, or by another contactless pulling device which is able to pull the holding plate through the blank. It is also possible to hold the holding plate mechanically against the carrier body from the outside after the frame has been withdrawn.

The second or further blanks can be applied to the carrier body in the same way as the first blank. In this case, the devices for applying the blanks have essentially the same structure.

If the first blank is to be sewn along its entire circumference with the second blank, the frame is expediently a closed frame. However, it is also possible to use an open frame in the event that only a part of the circumference of the first blank is to be sewn to the second blank. The frame can therefore also be a straight or curved rod.

In the following an embodiment of the invention will be explained with reference to the drawings.

Fig. 1

eine schematische Draufsicht einer Vorrichtung zum Nähen dreidimensionaler Hüllen.

Fig. 2

eine schematische Seitenansicht der Vorrichtung nach Fig. 1,

Fig. 3

einen schematischen Schnitt entlang der Linie III-III von Fig. 2 zur Verdeutlichung der beiden ersten Zuschnitte, die von den Haltevorrichtungen erfaßt sind, um an den Trägerkörper angesetzt zu werden, sowie des zweiten zuschnitts, der anschließend um den Trägerkörper herumgezogen wird,

Fig. 4

einen Schnitt entlang der Linie IV-IV von Fig. 3,

Fig. 5

die Übergabe eines ersten Zuschnitts von der Vorbereitungsstation an die Übertragungsvorrichtung, sowie die weitere übergabe von der Übertragungsvorrichtung an den Trägerkörper,

Fig. 6

einen Schnitt entlang der Linie VI-VI von Fig. 5 und

Fig. 7

das Zurückziehen des Rahmens von dem Trägerkörper sowie das Ablegen des Rahmens in der Vorbereitungsstation.

Bei dem beschriebenen Ausführungsbeispiel sollen Hüllen 10 für die Armlehnen von Kraftfahrzeugen genäht werden, wobei zwei erste Zuschnitte 11,12 die Stirnwände der fertigen Hülle bilden, während ein zweiter Zuschnitt 13 die Umfangswand der Hülle bildet und jeder seiner Ränder mit dem Rand eines der ersten Zuschnitte 11,12 vernäht wird.Show it:

Fig. 1

is a schematic plan view of a device for sewing three-dimensional envelopes.

Fig. 2

2 shows a schematic side view of the device according to FIG. 1,

Fig. 3

3 shows a schematic section along the line III-III of FIG. 2 to illustrate the two first blanks which are gripped by the holding devices in order to be attached to the carrier body, and the second blank which is subsequently drawn around the carrier body,

Fig. 4

4 shows a section along the line IV-IV of FIG. 3,

Fig. 5

the transfer of a first blank from the preparation station to the transfer device, and the further transfer from the transfer device to the carrier body,

Fig. 6

a section along the line VI-VI of Fig. 5 and

Fig. 7

retracting the frame from the support body and placing the frame in the preparation station.

In the described embodiment, sleeves 10 are to be sewn for the armrests of motor vehicles, with two first cuts 11, 12 the end walls of the form finished sleeve, while a second blank 13 forms the peripheral wall of the sleeve and each of its edges is sewn to the edge of one of the first blanks 11, 12.

A three-dimensional carrier body 14, which has approximately the shape of the casing to be produced, serves as the carrier for the blanks. The blanks are fixed to this carrier body 14 with mutually opposing edges in order to be sewn with a sewing machine 15 which is guided on a manipulator. The casing thus produced is then turned over so that the seams 16 are on the inside.

The in Figs. 1 and 2 has a rotatable column 17 on which three arms 18 are attached, each of which carries a support body. The carrier body is in the loading position 14a, in which the blanks can be placed on it. When the column 17 continues to rotate, the carrier body reaches the sewing position 14b of the carrier body, in which the sewing machine 15 sews the obliquely projecting edges of the blanks. When the column 17 continues to rotate, the carrier body reaches the removal position 14c of the carrier body, in which the finished casing is pulled off.

In the loading position 14a, in which the carrier body is located, first application devices 20 can engage it from both sides in order to attach the lateral first blanks 11, 12 to first contact surfaces 54 of the carrier body 14. Each of the first application devices 20 can be moved along a rail 21 running parallel to the carrier body.

The second blank 13 is placed in the loading position 14a by a second application device 55 on a second contact surface 56 of the carrier body 14. The second application device 55 has two grippers 22, 23, which can be moved on rails 24 and 25 parallel to the longitudinal direction of the carrier body 14 in order to grip the second blank 13 at its ends and to pull it around the circumference of the carrier body and hold it there. The second application device 56 follows the movements of the carrier body along the individual positions 14a, 14b and 14c and holds the blank 13 in firm contact with the contact surface 56, which here is the peripheral surface. As the exemplary embodiment shows, the contact surfaces do not necessarily have to be flat. The contact surface 56 is a curved surface here. It is important that the contact surfaces 54 and 56 abut against one another at an angle and form an edge.

4, each first contact device 20 has a slide 26 which can be moved along the rail 21 in question and which carries a horizontal piston-cylinder unit 27. A head piece 28 horizontally movable with the piston-cylinder unit 27 can be moved transversely to the longitudinal direction of the carrier body 14. A support 30 is attached to the head piece 28 via a horizontal axis 29, on which a piston-cylinder unit 31 engages in order to pivot the support 30 between the receiving position shown in FIG. 4 and the delivery position shown in broken lines in FIG. 5.

The carrier 30 is an elongated beam which has receiving holes 32 at its ends and a further receiving hole 33 in the middle.

The preparation station 34 is arranged at a fixed location along the path of the application device 20. This has a holder 35, which is designed as a support frame and has approximately the shape of the first blank 11 in question. The holder 35 is attached to a lifting device 36 so that it can be raised and lowered. In the inner free space of the holder 35 there is a support plate 37 which can be moved vertically relative to the holder 35 by a further lifting device 38 or against the force of a spring device.

4, the frame 40 is inserted into the holder 35, which has approximately the contour of the first blank 11. This frame has an upward shoulder 41 as shown in FIG. 4, an inclined shoulder 42 facing the inner shoulder 41 and an outwardly projecting flange 43. A tubular section 44 projects beyond the inner shoulder 41 and forms the rear end of the frame while the Oblique shoulder 42 forms the front end of the frame.

The frame 40 is loosely placed in the holder 35 designed as a support frame, being held on the short sides of the holder 35 in a clamp (not shown) and thereby centered. The support plate 37 is located approximately at the level of the inner shoulder 41. The blank 11 is placed on this support plate 37 so that it projects beyond the edge of the support plate and rests on the inner shoulder 41.

The frame 40 has two pins 45 projecting to the rear, which penetrate into the receiving holes 32 of the holder and can be locked there with controlled bolts.

In the frame 40, the holding plate 46 can also be used, which carries a rearwardly projecting pin 47 which can be inserted into the receiving hole 33 of the holder 30 and locked. After the fabric has been pressed into the frame 40, it is taken over into the bores of the holder 30 by the pins 45 and moved upwards together with the holding plate 46 and the fabric 11.

In the position shown in FIG. 4, the holder 35 with the frame 40 and the support plate 37 is raised by the lifting device 36, the pins 45 penetrating into the receiving holes 32 in order to be locked. The support plate 37 with the blank 11 lying thereon abuts against the holding plate 46 and withdraws under the action of the lifting device 38, as shown in FIG. 5. As a result, the edge 11a of the blank 11 bends backwards around the edge of the holding plate 46, whereby it comes to rest on the inner surface of the frame 40. Since the outer diameter of the holding plate 46 is only slightly smaller than the inner diameter of the frame 40, the edge 11a according to FIG. 5 is clamped between the holding plate and the frame. Since the holding plate and frame are now clamped together on the carrier 30, they remain on this carrier while the holder 35 is lowered by the lifting device 36. Now the carriage 26 is moved along the rail 21. The piston-cylinder unit 31 pivots the carrier 30 about its horizontal axis into the position shown in broken lines in FIG. 5, and the piston-cylinder unit 27 moves the carrier 30 in the direction of the carrier body 14 until the frame 40 in position 40a touches the end face of the carrier body. In this state, the holding plate 46 is still in the frame 40 in order to clamp the blank 11 tight.

After the blank 11 has come to rest on the front-side contact surface 54 of the carrier body 14, the second blank 13 according to FIG. 6 is drawn around the carrier body by the grippers 22 and 23. Shortly before the end phase, the grippers 22, 23 assume the positions 22a and 23a shown in dashed lines and in the end phase the ends of the fabric touch. The edge 13a of the second blank 13 projects laterally beyond the carrier body 14 and there it lies against the oblique shoulder 42 of the frame 40.

The carrier body 14 contains holding devices 50, which are designed here as electromagnets and which attract the holding plate 46 in the excited state. After both blanks 11 and 13 have been attached to the carrier body, the holding device 50 is activated. At the same time, the locking of the pin 47 of the holding plate on the carrier 30 is released. The holding plate 46 is now held by the holding device 15 on the carrier body 14 through the blank 11, while the frame 40 is removed from the carrier body 14 together with the carrier 30. Since the edge 11a of the first blank 11 is now freed from the constraint of the frame 40, it partially recedes and lies against the edge 13a of the second blank 13. An obliquely protruding edge strip results from the adjacent edges 11a and 13a. The seam is produced along the root line 57 of this edge strip by the sewing machine 15 according to FIG. 1 after the relevant support body has been pivoted into the position 14b according to FIG. 1.

The needle 52 of the sewing machine 15 is shown schematically in FIG. 7 in order to clarify at which point the blanks 11, 13 the seam is produced. Both blanks 11 and 13 are placed wrinkle-free and warp-free on the contact surfaces of the carrier body 14 arranged at an angle to one another. The needle 52 is then guided along the intended seam line, which runs precisely along the crease line, which is located at the foot of the web, which is formed by the two opposing edges 11a and 13a of the blanks. If sewing is carried out exactly along this root line 57, that is to say along an edge line of the carrier body 14, the correct seam course of the three-dimensional envelope is produced without the seam causing folds or distortions.

After completion of the sewing, the two holding plates 46 are temporarily removed from the carrier body in FIG. 1 in position 14b or in position 14c. Then, in position 14c, the carrier body is telescopically moved laterally, so that its width is reduced and the casing is no longer tightly seated on the carrier body. The loose casing is then removed from the carrier body, if necessary with simultaneous turning of its inside outwards, and the carrier body is moved into position 14a again after the holding plates 46 have been put on again in order to take up new blanks. The frame 40 remains on the carrier 30 of the transfer station 20. This carrier 30 is placed in the vertical position above the preparation station 34 and placed on the holder 35, as shown in FIG. 7. The support plate 46 is then removed from the support body 14 by the support 30, so that the state shown in FIG. 4 again arises, in which a new blank 11 can be placed on the support plate 37 and the frame 40.

Claims (12)

1. Method of forming three-dimensional coverings from a plurality of blanks (11, 13), which are sewn on their adjacently situated edges (11a, 13a) by means of a sewing machine, the blanks being laid on a carrier body (14) which comprises abutment faces (54, 56) extending at an angle to one another,
   characterised by the following steps:

   a) shaping a first blank (11) by means of a shaping tool so that the edge (11a) of the blank (11) extends at an angle to the (rest of the) blank (11);

   b) laying the preshaped blank (11) by means of the shaping tool on the first outer abutment face (54) of the carrier body (14), so that the edge (11a) of the blank (11) extends at an angle to the abutment face (54);

   c) retaining the first blank (11) on the abutment face (54) of the carrier body (14) by means of the shaping tool;

   d) laying the second blank (13) on a second outer abutment face (56) of the carrier body (14) so that its edge (13a) protrudes beyond the abutment face (56) and extends at an obtuse angle relative to the outside of the rest of the blank (13);

   e) fixing the blanks (11,13) to the carrier body (14) and removing the shaping tool; and

   f) causing a relative movement between the sewing machine and the edging strip, which is formed from the two edges (11a, 13a) of the blanks (11, 13), so that a seam (16) is produced along the base line (57) formed by the bend lines of the edges, said seam connecting the two edges (11a, 13a) of the blanks (11, 13).
2. Method according to claim 1, characterised in that the carrier body (14) is brought into a fitting position (14a), in which the blanks (11, 13) are laid, in that the carrier body (14) is then moved into a sewing position (14b), in which sewing with at least one sewing machine is effected along the base line (57), and in that the carrier body (14) is subsequently moved into a removal position (14c), in which the covering is removed from the carrier body (14).
3. Method according to claim 2, characterised in that the volume of the carrier body is reduced prior to the removal of the covering from the carrier body (14).
4. Apparatus for carrying out the method according to one of claims 1-3, having a carrier body (14) which comprises abutment faces (54, 56) extending at an angle to one another, on which abutment faces the blanks (11, 13) can be laid so that they can be sewn along their edges (11a, 13a), and having a sewing machine (15) which is guided in a movement-controlled manner, characterised in that a first laying device (20) is provided for laying the first blank (11) on a first abutment face (54) of the carrier body (14), said first laying device comprising a shaping tool (40, 46) for bending the edge (11a) of the blank (11) as well as a support face/inclined shoulder (42) for the edge (13a) of the second blank (13), in that a second laying device (55) is provided for laying the second blank (13) on the second outer abutment face (56) of the carrier body (14), said second laying device laying the edge (13a) of the blank (13) against the support face/inclined shoulder (42) in its delivery position, and in that the sewing machine (15) is so controlled that it produces the seam (16) along the base line (57) in which the first and second abutment faces (54, 56) encounter each other.
5. Apparatus according to claim 4, characterised in that the first laying device (20) is displaceable between a receiving position and a delivery position, said delivery position being located on the carrier body (14).
6. Apparatus according to claim 4, characterised in that the edge of the retaining plate (46) extends in accordance with the edge of the first laying device (54) so as to maintain a gap therebetween, and the frame (40) bends the edge of the first blank (11) protruding beyond the retaining plate (46).
7. Apparatus according to claim 6, characterised in that the retaining plate (46) is detachably mounted on the first laying device (20), which carries the frame (40), and in that, after the retaining plate (46) has been transferred to the carrier body (14), the first laying device (20) is removable from the carrier body (14), together with the frame (40), while only the retaining plate (46) remains on the carrier body with the first blank (11).
8. Apparatus according to claim 4, characterised in that a preparation station (34) is provided, which can receive the frame (40) in such a way that the first blank (11) is insertable in said frame, and in that the first laying device (20) introduces the retaining plate (46) into the frame (40) and conveys both with the first blank (11) to the carrier body (14).
9. Apparatus according to one of claims 4-8, characterised in that the first laying device (20) comprises a carrier (30) for the frame (40) and the retaining plate (46), said carrier being pivotable about a horizontal axis (29), and in that the preparation station (34) is disposed beneath the first laying device (20).
10. Apparatus according to claim 8 or 9, characterised in that the preparation station (34) comprises a raisable and lowerable holder (35) for depositing the frame (40) thereon.
11. Apparatus according to claim 10, characterised in that the preparation station (34) comprises a raisable and lowerable support plate (37) in the holder (35).
12. Apparatus according to one of claims 4-11, characterised in that the frame (40) comprises a supporting face, which is configured as inclined shoulder (42), on its side facing the carrier body (14) for raising the edge (13a) of the second blank (13).

Images