| 1. | 1) Automatic sewing machine for applying the lining to trousers waistbands which consists of a mechanical part comprising a bench 1, at least a supporting table 2, at a least a fabric discharger 3, at least a shears 4, at least a puller unit 5, at least a guide unit 6, at least a couple of pleaters 7, at least a couple of roll holders 8, several clamps and supports; an electric/electronic part comprising an electrical checkpanel, a control unit, photocells and several sensors; a pneumatic part comprising pistons and electrovalves; at least a sewinghead 9 and characterized by the fact that said automatic sewing machine is completely automatic and works in a different way according to the user's needs. |
| 2. | Automatic automatic sewing machine according to the claim 1 characterized by the fact that it allows flexible workings such as zigzag and/or straight sewing. |
| 3. | Process for applying the lining to trousers waistbands characterised by the automatic manufacture, both in alternate and in continuous, of the even and and the uneven pieces of a trousers waistband according to the following cycle phases: fabric loading, program selection and automatic sewing machine start, first notch reading, even strip cut and piling, sewing restart, cut of the fabric piece for the the uneven strip, second notch reading, uneven strip cut and piling, as described in the detailed disclosure. |
| 4. | Process for the transportion and the position control of the two fabric strips characterised by the fact that both strips can be moved forwards and backwards in an separate, adjustable and synchronisable way, keeping their position controlled. |
| 5. | Automatic sewing machine according to the claim 2, characterized in that said shears for the fabric cut is movable. This allows to cut without problems both even and uneven pieces for different waistband widths. |
| 6. | Automatic sewing machine according to the claim 2 or 5, wherein said sewing head is assembled on a special movable frame, which allows its movements independently of the other parts of the automatic sewing machine. |
| 7. | Automatic sewing machine according to the claim 2,5 or 6, wherein said puller unit allows the forwarding of the two fabric strip edges separately, for a defined and adjustable length, according to the desired pattern. |
| 8. | Automatic sewing machine according to the claim 2 or one of the claims from 5 to 7, characterised by several guides, completely orientable and adjustable at several points, provided with a supporting structure also adjustable both in height and in angular position, and a blowing element in the upper part. |
| 9. | Automatic sewing machine according to the claim 2 or one of the claims from 5 to 8, characterised by a tongue lifting device positioned at two critical points: the first one corresponding to the notch reading sensor, the second one corresponding to the shears for the waistband cut. |
| 10. | Automatic sewing machine according to the claim 2 or one of the claims from 5 to 9, characterised by a couple of pleaters, which have the double function of holding or pulling backwards the two waistband strips, separately, for a well defined but adjustable length, according to the desired pattern. |
| 11. | Automatic sewing machine according to the claim 2 or one of the claims from 5 to 10, characterised by two roll holders with a feeding device, which makes easy the fabric unrolling and forwarding; such device also avoids that the fabric is stressed during the machine working cycle. |
Due to these drawbacks, known in state of the art, several attempts to create automatic machines have been made, without a real commercial success, since these machines cannot substitute the manual work thouroghly and show low quality and flexibility.
Disclosure of the invention The invention solves the above mentioned technical problem because it is a completely automatic sewing station for sewing the lining to waistbands of trousers, characterized in handling many work steps differently according to the user needs. This is possible thanks to its synchronised fabric transportation and control mechanism, which assures an extreme versatility, even in case of complex workings, as, for example, pleats or checked fabric, straight and"zig-zag"sewing.
This machine operates without any workers assuring a very high
quality level.
These and other advantages will be pointed out in the detailed description of the invention that will refer to the figures of the tables 1-8 in which a preferred embodiment of the invention is shown. It is examplifying and not restrictive.
Way of carrying out the invention With reference to the above mentioned tables: 'Figure 1 shows the sewing machine assembly; Figure 2 shows the detail of fabric strip, used for the trousers waistband; Figure 3-13 represent the different working steps of the sewing machine, as below described.
With reference to Fig. 1, according to the invention, the sewing machine comprises the following components: Mechanical part comprising the bench (1), the supporting table (2), the discharger (3) (which allows the piling of the waistbands at the end of the cycle), the shears (4), the puller unit (5), the guide unit (6), a pleater (7), one of them with auxiliary guide system, the roll-holder (8), several clamps and supports; Electric/electronic part comprising the electrical control panel, the control unit, which defines and controls the automatic movements, photocells and several sensors; Pneumatic part comprising pistons and electrovalves (control
unit actuators); Sewing-head (9) The automatic sewing machine is used in the manufactoring of classical trousers. In particularly, it produces the two pieces, left and right, forming the trousers waistband. In a further operation the two pieces are sewed together and assembled to the trousers.
The automatic sewing machine allows to cut and sew together the two fabric strips (one pre-machined (10), the second one glued (11)), which form the internal and external part of the trousers waistband, respectively.
According to the size, the two parts can have a variable length, but one must be even (10'and 11') and the other one uneven (10" and 11") (Fig. 2). Sometimes, the lenght of the uneven strip can vary according to the pattern. In other cases, for example, pleated trousers or checked fabric, before being sewed, the two strips should be found one respect to the other in a well defined position. The desidered positioning of the fabric is provided by a synchronized transportation and control mechanism, which moves the two fabric strips independently until they are in the desired position. Consequently, the working cycle of this machine can follow different procedures, according to the kind of job to be performed.
A typical working cycle of the machine comprises the following operations : A) FABRIC LOADING : the facric is loaded on suitable roll
holders (8) and then passes under the guide unit (6), which allows the two fabric strips (the premachined (10) and the glued (11)) to reach under the needle (15) side by side and be sewed (Fig. 3).
The facric is loaded manually only th first time, at the beginning of the operation, afterwards, the machine works automatically.
B) PROGRAM SELECTION AND MACHINE STARTING: after selecting the desired program from the display, pushing a start button the sewing head (9) begins sewing the two fabric strip-edges.
C) FIRST NOTCH READING: while sewed, the waistband piece moves forward until when the tongue lifting device (12) (in front of the guide) uncovers a first notch (14), which defines the even strip of the waistband. An optical fiber sensor (13), mounted before the needle (15), reads the first notch and sends the signal to the control unit (Fig. 5). At this point, the sewing head stops sewing, the puller (5) moves the sewed waistband part in such a way that the notch is exactly under the shears (4) (Figs. 6 and 7).
D) EVEN PART CUT : the shears (4) cuts both edges of the sewed waistband at the desired length (the length is decided according to the size). At this point, a tongue lifting device, close to the shears, operates to makes the cut more precise (Fig. 7).
E) EVEN PART PILING: once the piece has been cut, it is piled by the the discharger (3), thus finishing the manufacturing of the even piece of the waistband (Fig. 8).
F) SEWING RESTARTING: the puller (5) pulls forward only the
glued piece, while a pleater (7) holds the premachined piece, so that the length of the uneven piece is the desired one. Then, the sewing head restarts sewing, leaving part of the lining strip unsewed (Fig. 9a). In some cases, as for example with pleated trousers or checked fabric, the unsewed part of the strip has to have a variable length according to the garment's pattern. To do this, two pleaters (7) pull backwards the two waistband strips, until they are in a precise position. Additionally, this process avoids waste of the premachined waistband: in fact, in this way it is possible to minimise the piece length, which, after cut by the shears, is rejected (Fig. 9b).
G) FABRIC EDGE CUT: once the sewed piece is under the shears (4), the sewing head (9) stops and the shears is moved backwards to cut only the unsewed piece on the side of the premachined waistband (10") (Fig. 10). At this point, the uneven piece of the waistband is ready.
H) SECOND NOTCH READING: the sewing head (9) restarts sewing (Fig. 11) until the optical fiber sensor (13) reads the second notch (14) and further until the second notch (14) is under the shears (4) (Fig. 12).
I) UNEVEN PIECE CUT: at this point, the sewing head (9) stops for a little while, the shears (4) mowes forwards and cuts both the waistband strip edges (Fig. 12).
L) UNVEN PIECE DISCHARGE: the uneven piece is discharged (Fig. 13), the sewing head (9) restarts sewing and the cycle
restarts from point C).
In view of the above description, it is possible to point up the innovative characteristics of the automatic sewing machine. First of all, the machine working cycle is completely automatic: this means that the machine does not need any operator.
Moreover, the sewing head is assembled on a special movable frame, which allows its movements independently on the other parts of the automatic sewing machine. In fact, repairing or regulations can be performed on the lower side of the sewing head with enough room to move. Furthermore, the sewing machine ca be loaded without moving the fabric guides (whose position is crucial for the high-quality manufactoring of the waistband). The roll holders are provided with a feeding device, which helps the fabric unrolling and its forwarding; avoiding the fabric tightness during the machine working cycle. The shears is movable allowing to cut easily bothe the even and uneven pieces at different waistband lenghts. The machine is also provided with a synchronized fabric transportation and control system, which allow to move the two fabric strips separately and in an adjustable way, before or after being sewed, until they are at the desired position. This transportation system comprises a puller unit, the pleaters, several sensors in suitable positions and an auxiliary guide, which does keeps the folding of the premachined piece undamaged, even when the latter is pulled backwards. The machine is supplied with a completely orientable guide unit. The
metal sheet guides for the fabric folding are adjustable at several points. In addition, also supporting frame of these guides is adjustable both in height and in angular position, to allow any configuration which facilitates the waistband sliding. In the upper part, the guide is also provided with a blowing element which heps the fabric folding.
The automatic automatic sewing machine is provided with a tongue lining device at two critical points: the first one corresponding to the notch reading sensor, the second one corresponding to the shears for the waistband cut. Such device allows to paste the fabric to the adhesive film, overlapping the two, without dirtying the glued piece.