US 3572270 A
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March 23,, 1971 s. J. KETTERER STITCHED SEAMS Filed Oct. 28, 1969 l N VEN'IOR. Stanley J. Ketterer BY WM y ATTORNEY United States Patent Office 3,572,270 Patented Mar. 23, 1971 3,572,270 STITCHED SEAMS Stanley J. Ketterer, Morris Plains, N.J., assignor to The Singer Company, New York, NY. Filed Oct. 28, 1969, Ser. No. 870,043 Int. Cl. Dc 17/00 U.S. Cl. 112-433 4 Claims ABSTRACT OF THE DISCLOSURE A stitched seam in which a single row of securing stitches parallel to the edges of two plies of fabric also anchors a pair of edge covering threads each extending about the edge of a respective one of the plies of fabric.
BACKGROUND OF THE INVENTION Thisinvention relates to edge finishing seams and is particularly advantageous when used to sew together the edges of two plies of fabric which are susceptible of ravelling or of which the individual fibers have poor cohesive qualities and tend to separate readily. Under the above mentioned conditions it is known in the art to provide each ply edge with an overedge stitch which anchors the fabric fibers against ravelling or separation and then to provide a securing stitch inwardly of the edge from the overedge stitch. Using previously known stitched seams, at least two separate lines of stitching were required in order to bind each of the two ply edges with threads and stitch the plies together. Heretofore, this could be accomplished by passing the work several times through a plain overedging sewing machine or by using a complicated special sewing machine with tandem stitching mechanisms for sewing the separate seams in one pass, as for instance is disclosed in U.S. Pat. No. 3,192,887, July 6, 1965.
SUMMARY OF THE INVENTION This invention provides for the edge stitching of fabrics such as knit goods which can ravel or of fabrics of which the fibers can pull out easily as in the case of many fabrics woven of synthetic material. A single row of stitches parallel to the edges of the plies of fabric secures the plies together and a separate edge covering thread is arranged back and forth over the edge of each of the plies of fabric with loops of the edge covering threads embracing the stitches in the row of securing stitches alternately between the plies and at one side of the plies.
DESCRIPTION OF THE DRAWING The present invention is illustrated in the accompanying drawing in which:
FIG. 1 represents a diagrammatic perspective view of the stitched seam of this invention in which the plies of work fabric are illustrated in abnormally spaced relation and in phantom lines, and in which each of the threads forming the seam are shown with a different shading,
FIG. 2 represents a perspective view of a fragment of work fabric formed with a seam of this invention and in which the various threads are shaded corresponding to the shading used in FIG. 1, and
FIG. 3 is a cross sectional view taken substantially along the single row of stitches.
In the drawing, the upper and lower plies of fabric are designated by the reference characters 11 and 12 respectively. Substantially parallel to the edges 11 and '12 of the fabric plies 11 and 12 respectively extends a row of securing stitches indicated generally at 13 and comprising an upper thread 14 which is formed into successive loops 15- which are passed through both plies of fabric 11 and 12 at spaced intervals. Concatenated with the needle thread loops 15 beneath the fabric plies is a locking thread 16. The securing stitches 13 illustrated in the drawings are two-thread chainstitches, Federal Stitch Type 401, but it will be understood that any other type of stitch providing a single row of concatenated thread loops through the fabric may be used.
For binding the edge 11' of the top fabric ply 11, an edge covering thread 17 is formed into successive loops 18 over the upper ply 11 and loops 18 under the upper ply, i.e., the loops 18 extend between the plies 11 and 12 as clearly shown in FIG. 3. Each of the loops 18, 18 embraces one of the upper thread loops 15 in the securing seam 13 and between the loops 18, 18' the thread extends over the edge 11' of the upper fabric ply 11.
An edge covering thread 19 is similarly provided for binding the edge 12 of the lower fabric ply 12. The thread 19 is formed into successive loops 20 under the lower ply r12 and with loops 20' over the lower ply, i.e., between the plies. Each of the loops 20, 20' embraces one of the upper thread loops 15 in the securing seam 13 and between the loops 20, 20' the thread extends over the edge 12" of the lower fabric ply.
Preferably, as shown in the drawing, both edge covering threads 17 and 19 embrace each loop 15 of the row of securing stitches to provide the greatest density of edge covering stitches. The seam in accordance with this invention, however, may be formed with either or both of the edge covering threads engaging less than all of the securing stitch loops with a resultant decrease in density of the threads extending over the edge of the fabric plies. It is also preferable as shown in the drawing, for only one of the edge covering threads 17 and -19 to be formed with a loop 18 or 20' extending between the plies in embracing relation with any one loop 15 of the securing seam 13'.
Having thus set forth the nature of this invention, what is claimed herein is:
1. A stitched seam for uniting the edges of two plies of fabric comprising a row of securing stitches passing through said plies of fabric parallel to the edges thereof, and a pair of edge covering threads each formed with successive loops embracing thread in said row of stitches, and between said successive loops each edge covering thread extending over the edge of a respective one of said plies of fabric.
2. A stitched seam as set forth in claim '1 in which the loops formed in each one of said pair of edge covering threads alternately embrace thread in said row of securing stitches between said two plies of fabric.
3. A stitched seam as set forth in claim 2 in which the loops in each of said edge covering threads embrace thread in each successive stitch of said row of securing stitches.
4. A stitched seam as set forth in claim 1 in which said row of securing stitches comprises an upper thread of which successive loops are passed through said plies of fabric from one side thereof, and a locking thread References Cited UNITED STATES PATENTS 3/1873 Howard et al 112433X 1/1908 Weis 112436 4 Goldwyn 112269 Sandberg et al 112162 Lutz 112162 Perl 112162 Reeber et al. 112162 Russell 112433 ALFRED R. GUEST, Primary Examiner