Silvercrest SON 90 A1 - Manual (Page 127)

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Differential transport
Manner of operation
The machine has two sets of toothed rack feeders, one to the front and one
to the rear. Both sets move independant of each other. Through the differential
feed motion both toothed rack sets can move themselves at various speeds.
With this, the fabric is stretched or gathered, depending on which transport
differential has been set between the front and rear rack feeders.
With the aid of the differential transport, interesting effects can be achie-
ved when sewing overlock seams on stretch materials and diagonally cut
fabrics (Fig. 43).
Note:
When the differential transport lever 9 stands at "1.0", that corresponds
to a differential transport ratio of 1:1. Both toothed feed racks move at the
same rate (Fig. 42).
The differential transport lever 9 can be adjusted in a range from 1:0.7
to 1:2.0.
Gathered overlock seam - Settings
The gathered overlock seam is suitable for the ruffling of sleeves, back
upper parts, skirt seams etc.made of elastic materials such as knitwear
and jersey. The individual parts should be brought together before sewing.
• Adjust the differential transport lever 9 to a value higher than 1.0
(Fig. 44). The exact setting depends on the material to be processed
and the desired level of ruffling or gathering.
Therefore always do a sample stitching to test the settings.
Stretched overlock seam - Settings
The stretched overlock seam is suitable for the manufacture of ruffles at the
collar, cuffs and skirt edges etc. in soft, stretchy fabric and knitwear.
• Adjust the differential transport lever 9 to a value lower than 1.0 (Fig.
45). The exact setting depends on the material to be processed, and
on the strength of the desired "ruffle effect".
Therefore always do a sample stitching to test the settings.
• Hold the seam down with slight firmness before and behind the sewing
foot a so as to keep the textile under tension.
Note:
If you have set a value of "3" or higher on the adjustment wheel for the
stitch length 5, this setting will automatically return to "3" when you set the
differential transport lever 9 to 2.0.
Fig. 42
Fig. 43
Fig. 44
Fig. 45
IB_64780_SON 90 A1_LB5 09.03.2011 16:22 Uhr Seite 125