Rangebring, Chris (Solglimten, Hallagärdesvägen 23, Fristla, S-511 73, SE)
| 1. | Device in connection with the shaping of a single or double hem on a fabric (40), which device comprises a first and a second endless, driven belt, which belts are arranged to feed the fabric forward in the device, on a horizontal feed support (10), characterised in that said second belt is constituted by a belt (18) which can be variably angled in the horizontal plane, in relation to said first belt (12), such that the second, variable angle belt (18) and the first belt (12) converge in the feed direction (14) of the fabric, the device also comprising means (26) for controlling an angle (a) between the second, variable angle belt and the first belt, so that a width of said hem is adjustable by choice of a magnitude of the angle. |
| 2. | Device according to claim 1, ch aracteri s ed i n a lifting bar (24), which is adjustable in the vertical plane, preferably by said means (26) for adjusting of the angle (a), and which is arranged to hold up an amount of fabric (30) which is defined by the chosen angle. |
| 3. | Device according to claim 1 or 2, characterised in that said second, variable angle belt (18) also constitutes a hem folding belt, which is arranged to be turned 180° about its own longitudinal axis, about a second folding bar (48), for folding of the part of the fabric (40) which is to form the hem. |
| 4. | Device according to any one of the preceding claims, characterised in a third, endless, driven belt (38), which is constituted by a hem folding belt, which is essentially shorter than said first and second belts (12,18) and arranged to be turned 180° about its own longitudinal axis, about a first folding bar (44), for folding of the part of the fabric (40) which is to form a double hem. |
| 5. | Device according to any one of the preceding claims, characterised in that said second, variable angle belt (18) extends all the way into and through a sewing machine (36) which is arranged to perform a seam in the hem. |
| 6. | Device according to any one of the preceding claims, characterised in means (26) for the adjusting of a speed of said variable angle belt (18) in relation to a speed of the first belt (12), which constitutes a transport belt, which means preferably consists of said means for adjusting of the angle (a). |
| 7. | Device according to any one of the preceding claims, characterised in a fourth, endless, driven belt (20), which is essentially shorter than said first and second belts (12,18) and which is constituted by a tension belt which is arranged in a feedingin position of the device, which fourth belt (20) is arranged to run in the main parallel with said first belt (12), the device preferably comprising means for the adjusting of a speed of this fourth belt, independent of the speeds of the first and second belt (12, 18). |
| 8. | Device according to any one of the preceding claims, characterised in that the width of said hem is adjustable to between 10 and 100 mm, preferably between 10 and 80 mm, by choice of size of said angle (a). |
| 9. | Method in connection with the forming of a single or double hem on a fabric (40), by aid of a device which comprises a first and a second endless, driven belt (12,18), which belts feed the fabric forward in the device, on a feed support (10), characterised in that said second belt (18) is angled in the horizontal plane, in relation to said first belt (12), such that the second, angled belt and the first belt converge in the feed direction (14) of the fabric, an angle (a) between the second, angled belt (18) and the first belt (12) being controlled for adjusting of a width of said hem. |
PRIOR ART AND PROBLEMS It is a desire in connection with industrial sewing of hems, e. g. on bedclothes such as sheets, on towels, curtains, shower draperies or other home textiles, that the width of the hem should be adjustable in a simple way, irrespective of if it is a single or a double hem. Especially, it is a desire that the width of the formed hem should be adjustable in connection with the changing of product in the hem folding machine, so that one and the same machine may be used for a variety of different products having different hem width, without any major manipulations of the machine being necessary.
Older patents/applications which partly deal with the problem of being able to adjust the width of a hem are SE 8004598-2, SE 8203288-9, EP 158 614 and US 4,648,336.
BRIEF ACCOUNT OF THE INVENTION The present invention aims at providing a device and a method for the shaping of a single or double hem on a fabric, which device is designed for easy adjusting of the width of the hem, with one or a few manipulations when the device is being adjusted. It is preferred that the width of the hem can be adjusted to at least between 10 and 100 mm, preferably between 10 and 80 mm. Another object of the device according to the invention is that it should enable pulling-in of the edge at the rear end of the hem, in order to avoid a"tongue"that projects out of the hem.
These and other objectives are achieved by the device and the method according to the invention, such as they are defined in the claims.
The principle of the inventive device is based on the idea to create an amount of the fabric which projects out from the plane of the rest of the fabric, which amount of fabric defines the width of the hem. Thanks to this amount of fabric having the same extension in the plane of the rest of the fabric (normally the horizontal plane), irrespective of the
width of the hem, there may be fixedly positioned in the device one or two folding devices for folding of the fabric into a single or double hem, as well as a sewing machine for the making of a seam in the end of the hem which is opposed to the free, folded edge. In other words, the invention enables that the width of the hem may be easily varied, in spite of the fact that the positions in the device that achieves the free, folded end of the hem and the seam in the opposite end of the hem are fixed in a direction which coincides with the extension across the hem (i. e. its width).
According to the invention, the projecting amount of fabric which defines the width of the hem is formed by two endless, driven belts, the first belt being a transport belt and the second belt being a belt which can be variably angled in the horizontal plane in relation to said transport belt, such that the variable angle belt and the transport belt converge in the feed direction of the fabric. The device also comprises means for controlling an angle between the variable angle belt and the transport belt, so that a width of the hem may be adjusted by choice of the magnitude of the angle.
DRAWINGS DESCRIPTION In the following, a preferred embodiment of the invention will be described in greater detail, with reference to the drawings, of which: Fig. 1 very schematically shows the device according to the invention, as seen from above, Fig. 2 shows six different steps in the shaping of the hem in the device according to Fig. 1, as seen in cross section.
Fig. 1 is very schematically showing a preferred embodiment of the device according to the invention, as seen from above. A feed table 10 for the fabric to be hemmed in the device is arranged in a feeding-in position of the device. The fabric is not shown in Fig.
1, but its feed direction is indicated by an arrow 14. The fabric is arranged such that the free amount of fabric, which is not to be hemmed, hangs down at the side of the feed table 10 (the right side in the shown figure). A first endless, driven belt 12 is arranged with a longitudinal extension which is parallel to the feed direction of the fabric. This first belt 12 constitutes a transport belt. Yet another, somewhat wider, transport belt 16 is arranged outside the transport belt 12, which transport belt 16 is arranged to run in parallel with the first transport belt 12. A second belt 18 is constituted by an endless, driven belt which can be variably angled in the horizontal plane in relation to the first transport belt 12, for the formation of an angle a which converges in the feed direction
14 of the fabric. Means, symbolised by 26, are arranged for the controlling of the angle a. Since the variable angle belt 18 will have a longer path to go than the transport belt 12, the variable angle belt 18 is arranged to run at a somewhat greater speed than the transport belt 12.
A short, introductory, endless, driven belt 20 is arranged in the main parallel with said first transport belt 12. In the following, this belt 20 is called a fourth belt or a tension belt. The fourth belt 20 may be arranged completely in parallel with the transport belt 12, or it may be arranged to diverge in relation to the same, quite slightly, in the feed direction 14. The purpose of the fourth belt 20 is to tension the fabric as it is being feed in, to prevent the hem from wringing. In the figure, the fourth belt 20 is drawn as to be driven about the same roller 22 as the second, variable angle belt 18. According to an alternative embodiment, the fourth belt is however arranged to be driven about separate rollers, so that its speed may be controlled individually. Hereby, the fourth belt 20 may be run at a bit higher speed at the end of a hem which is formed in the device, for avoiding that a"tongue"of the back corner of the fabric projects out of the hem. The free edge of the fabric which is to be folded into the hem is namely positioned beneath the fourth belt 20. The position at the fourth belt 20 corresponds to step A in Fig. 2.
When the fabric runs between the converging belts 12 and 18, there is formed an amount of fabric 30 (see Fig. 2) which can not extend itself in the horizontal plane in the ever narrowing space between these belts. Accordingly, the amount of fabric 30, will be forced to project out of the horizontal plane and form a"fabric bump". A lifting bar 24 is arranged to hold up this amount of fabric 30, the size of which being defined by the chosen angle a. Preferably, the bar 24 is arranged such that it follows the adjusting of the angle a, by the means 26 for adjusting of the angle a. The lifting bar 24 is pivotal about a point 28 in its proximal end. Suitably, the means 26 for adjustment of the angle a is arranged also to adjust the vertical height of the lifting bar 24, which height is maximal at the distal end of the bar, as well as its horizontal position essentially in the middle between the variable angle belt 18 and the transport belt 12. It is also preferred that the means 26 for adjustment of the angle a is arranged to control the speed of the variable angle belt 18, since all these parameters depend on the choice of the angle a.
The adjusting of the angle a is suitably manually performed, by the means 26, based on an indicated chosen width of the hem.
A first hem folding station 32 is arranged at the distal end of the lifting bar 24, for the first folding of the fabric edge in the two steps necessary for the forming of a double
hem. This hem folding corresponds to steps B and C in Fig. 2. The hem folding itself takes place by a shorter endless belt 38 (Fig. 2) which is turned 180° about its own longitudinal axis. The principle for this hem folding is known per se, reference being made to e. g. US 4,648,336, Fig. 12 and the related description. In this figure 12 in US 4,648,336, there is also shown means for a second hem folding, for the formation of the double hem. In the present case, this corresponds to a second hem folding station which is symbolised by 34 in Fig. 1 and which corresponds to steps D and E in Fig. 2. One difference in relation to US 4,648,336 should however be mentioned-in the present invention the endless belt which is turned 180° about its own longitudinal axis, for the formation of the second fold in the hem, is constituted by the variable angle belt 18, which moreover runs the entire way through the hem folding machine, all the way up to and through a sewing machine 36. In Fig. 2, the sewing machine corresponds to step F.
In Fig. 2, the different steps A-F of the hem forming are shown, as seen in cross section.
The positions of the different steps have also been pointed out in Fig. 1.
Step A The fabric 40 is fed in onto the feed table 10, so that its free edge is positioned beneath the tension belt 20 which makes sure that the fabric does not wring in the hemming.
Here, the distance between the variable angle belt 18 and the transport belt 12 has its greatest nominal value in the device.
Steps B-C As the variable angle belt 18 gets closer to the transport belt 12, due to them converging towards each other, a bump 30 is formed in the fabric, which bump is lifted (held in place) by the lifting bar 24. In step B, the endless belt 38 is arranged so that one of its longitudinal edges is positioned approximately above a centre line of the variable angle belt 18. Typically, the belt 38 is also wider than the belt 18. In the first hem folding station 32, the free edge 42 of the fabric is folded by the endless belt 38, which is turned 180° about its own longitudinal axis, about a first folding bar 44. Thereby, a first folded edge 46 is formed in the fabric in steps B-C.
Steps D E In step D, the lifting bar 24 has ended, allowing the bump 30 to fall down for formation of the hem, from step D to step E. In step D-E, the edge 46 is folded about a second folding bar 48. This folding bar 48 is profiled such that it exhibits a vertical surface in step D, supporting the belt 18 which is now in vertical position. Thereafter, this vertical
surface gradually turns to constitute a horizontal bottom side of the folding bar, supporting the belt 18 which in step E has turned 180° in relation to its orientation in step C. In this connection, yet another endless belt 50 enters in parallel with the belt 12 and close to the same, to constitute a support for the belt 18 when the folding bar 48 ends. A second folded edge 54 is formed in the fabric in steps D-E.
Step F In step F, the now fully folded, double hem is led into a sewing machine 36, having a needle 52. The needle enters into the fabric in a position between the transport belt 12 and the belts 50 and 18, lying on top of each other. Hereby, a seam is achieved, which is 3 mm, or any other chosen distance, from the folded edge 46.
The invention is not limited by the embodiment described above, but may be varied within the scope of the following claims. Thus, it is e. g. realised that the inventive principle may be used also in connection with the forming of a single, i. e. a singly folded, hem. Referring to the claims, it should also be realised that that which is stated to be horizontal or vertical mainly should be interpreted as an indication about the details relative position in relation to each other, the invention naturally also functioning when the device is positioned with another relation to the room/surroundings.
Furthermore, the invention also comprises, in its widest interpretation, a device with other feeding means, converging in the feed direction, which feeding means are equi- valent to the transport belt and the variable angle belt, for achieving of the amount of fabric projecting out of the horizontal plane.
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