Mechan Ical Principle Of The Pfaff -261 Automatic - Pfaff 260 Service Manual

Machines incorporating the principle of direct needle bar frame control work
differently. They ore so designed that both the zigzag regulator stud and the
needle bar frame ore operated from the pattern com direct (see Fig. 44); in
other words, the sideways motion of the needle bar frame is not derived from
on eccentric.
Each pattern com normally produces only one basic embroidery design. To
change over from one design to another, a new pattern com must be inserted
in the machine.
Mecftanical Principle of the Pfaff -261 Automatic
Both the Pfaff 260 flat-bed and the Pfaff 360 free-arm sewing machines are so
designed that they con be converted into automatic machines at any time.
The automatic embroidery mechanism used for these machines con be easily
installed in the mochin· e arm. This arm, wh ich is open at the top, is closed with
a special top cover supplied with the automatic embroidery mechanism.
In contrast to automatic devices which ore so designed that the throw of the
pattern com is transmitted to the needle bar frame· directly (Fig. 44), the Pfaff
automatic embroidery mechanism controls the need le motion indirectly, i.e.
through the needle position and stitch width regulator assemblies. As a result,
1
Fig.
44
Diagram showing the mechanical principle of direct needle
bar frome control
7
1
=
Pivot
2
=
Feeler finger
3
=
Pattern cam
4
=
Slide block
5
=
SloHed lever
6 = Pivot
7
=
Needle bar frame pitman
8 = Needle bight
9
=
Needle plate
10
=
Needle bor
11
=
Needle bar frame
0
=
No needle throw (straight stitch)
23