Sewing – Elements – Frames
Patent
1991-02-13
1992-04-14
Nerbun, Peter
Sewing
Elements
Frames
112306, 112314, 112320, 112153, D05B 2706, D05B 2714
Patent
active
051037491
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention pertains to a process and a sewing machine for two dimensionally aligning and sewing together two fabric layers having the same surface structure according to a pattern. The sewing machine is provided with an upper and lower feed means for varying the feed of the fabrics relative to each other by means of at least one setting device. An edge guiding device is associated with one of the two fabric layers, and first and second aligning means are provided for affecting aligning movement. At least one edge sensor is provided for determining the lateral distance between the edge adjacent to the seam to be produced in one of the fabric layers and the stitch formation site of the sewing machine. A matrix camera is provided with a surface sensor, and connected to an image memory associated with each fabric layer.
BACKGROUND OF THE INVENTION
A pattern aligning device for a sewing machine, is known from U.S. Pat. No. 4,757,773 (based on West German Offenlegungsschrift No. 3,738,893). Using the prior-art device, it is possible to sew together, according to a pattern, two fabric layers having the same surface structure or the same pattern. In the case of, e.g., a check pattern, first pattern lines of one of the fabric layers extending at right angles to the seam line are to be aligned with the corresponding pattern lines of the other fabric layer, and second pattern lines of the other fabric layer extending in parallel to the seam line are to have the same lateral distance from the seam line as the corresponding pattern lines of the other fabric layer.
As a prerequisite for aligning pattern lines extending in parallel to the seam line, one of the fabric layers first must be aligned to a predetermined edge distance from the stitch formation site. An edge sensor is provided for this purpose, which determines the distance to the edge of the fabric layer. If the actual distance value deviates from the nominal distance value, the aligning means of the corresponding edge guiding device is actuated so that the deviation between the nominal value and the actual value is eliminated. The other fabric layer is now aligned to the correct pattern by means of the other aligning means of the edge guiding device on the basis of the data obtained for a transverse mismatch that may be present by the cross-correlation analysis.
The prior-art pattern aligning device is used mainly to produce the center back seam on jackets, because perfect appearance of this seam is a very important quality criterion for the evaluation of the overall quality of these garments. It is very important here, in the case of check patterns, for the transversely extending pattern lines of the left and right parts to be perfectly aligned with each other and for the longitudinally extending pattern lines to be located at exactly the same distance from the seam line. However, because of the greater width of the jacket in the shoulder area, pattern lines that are otherwise aligned in parallel to the seam line enclose an acute angle with the seam line in this area. In the case of certain patterns, in which the distance between longitudinally extending pattern lines exceeds the width of the surface sensor, it may now occur in the shoulder area that the obliquely extending longitudinal lines move out of the field of measurement of the surface sensor, so that no longitudinal lines can be detected for a certain length of time, and consequently no signal indicating the transverse distance of the longitudinal lines can be obtained. Even though it would now be possible to use surface sensors of correspondingly large size in order to avoid this situation, such surface sensors are extremely expensive.
SUMMARY AND OBJECT OF THE INVENTION
The object of the present invention is to provide a process and a sewing machine for sewing together fabric layers according to a correct pattern. The process and sewing machine make it possible to process, in a simple manner, even patterns in which longitudinally extending pattern lines or s
REFERENCES:
patent: 4757773 (1988-07-01), Nomura et al.
patent: 4982677 (1991-01-01), Nomura et al.
patent: 5001998 (1991-03-01), Suzuki et al.
patent: 5012752 (1991-05-01), Murata et al.
Frank Manfred
Geisselmann Heribert
Jehle Fritz
Willenbacher Erich
Nerbun Peter
Pfaff Industriemaschinen GmbH
LandOfFree
Process and sewing machine for sewing together layers of fabric does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process and sewing machine for sewing together layers of fabric , we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process and sewing machine for sewing together layers of fabric will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2341930