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16. Automatic Thread Release
The Supermatic and Transforma, up to Serial No. 527,625,
had two simple Stop Springs to hold the stationary portion of
the shuttle in place and for the release of the upper thread.
The Shuttle Beak sits between the Stop Springs with a certain
amount of clearance. As the shuttle rotates, the Shuttle Beak
comes to rest against the Stop Spring preventing the two
assembled guard rings from rotating.
The thread must force its way between the Stop Spring and
the Shuttle Beak pressing against it. This slight displacement
of the Shuttle Beak induces additional tension in the upper
thread which is more pronounced, the more the Shuttle Beak
presses against the Stop Spring.
It is important to keep these additional tensions as low as possible to minimize their influence on the quality of
the sewing. Lubricate the shuttle with kerosene and not oil. Kerosene's lower viscosity reduces the friction more
than oil and thus reduces the additional tensions.
ELNA introduced the automatic Thread Release on
Supermatic and Transforma machines starting approximately
with Serial No. 527,626.
The automatic Thread Release allows the upper thread loop
to pass freely in and out of the shuttle beak and guard ring
stops at the moment it is drawn out of the shuttle by the
thread Take‐up Lever resulting in greater regularity in the
thread tensions and high quality stitches.
The Loop Spring was added to the automatic Thread Release
starting approximately with Serial No. 627,000.
The Loop Spring ensures that the loop of upper thread does
not escape too early and passes in the right position out of
the shuttle before it is drawn up into the material by the
thread Take‐up Lever, thus preventing the loop from twisting
and forming knots in the seam.
The Thread Release pivots up‐and‐down when the machine is
running. It is driven by the Release Skid which rides against
the Release Cam as it rotates on the Lower Shaft.
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