Eccentric Bush - Duerkopp Adler 271 Service Manual

2.3.1 Eccentric bush

Regulation and inspection
Class 271/273/275
The eccentric bush 1 is adjusted at the factory so that at TDC the feed
dog is parallel to the needle-plate surface. In the basic position the slit
is horizontal (Fig. A).
When the feed dog emerges from the needle plate its back end
emerges first.
When the slit of the eccentric bush is in the down position (Fig. B), the
feed dog emerges from the needle plate in parallel. This avoids
stretching the material. This is particularly important with stretch
material or material which is inelastic in the warp and weft directions
but which stretches when sewn in the diagonal direction.
When the slit of the eccentric bush is in the up position, the feed dog
is at a greater angle (Fig. C) when it emerges from the needle plate.
This angled emergence improves "smooth sewing" with inelastic
material such as poplin and certain lining materials. If necessary the
eccentric bush can also be placed in intermediate positions.
Class 272/274
The eccentric bush 1 is adjusted at the factory so that at TDC the feed
dog has a slightly rearwards slope. In the basic position the slit is at an
angle of 45° to the horizontal (Fig. D).
IMPORTANT
If the eccentric bush has been altered, the feed-dog height must be
re-adjusted (see section 2.3).
Caution: danger of injury
Turn off the main switch.
The eccentric bush may only be adjusted with the sewing machine
switched off.
Adjustment
–
Undo screw 2.
–
Adjust eccentric bush 1.
–
Retighten screw 2.
11