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US 4,214,540 AGranted
Variable presser bar pressure control arrangement
AssigneeThe Singer Company
InventorAlbert N. Cook
Life of this patent
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Abstract
A sewing machine having a presser bar operated by a lever having a movable fulcrum to vary the mechanical advantage of the lever and thereby vary the effective pressure on the presser bar.
Claims13
In a sewing machine comprising a body, a feed mechanism for incrementally advancing a work piece to produce a series of stitches, and a presser bar with a presser foot attached thereto for urging said work piece into engagement with said feed mechanism, variable presser bar pressure control means comprising:
- a rigid lever, said presser bar operatively engaging said lever at a first point on said lever;
- means for applying a predetermined force to a second point on said lever spaced from said first point;
- a shiftable fulcrum for said lever;
- and
- means for shifting said fulcrum along said lever to vary the mechanical advantage of said lever to control the pressure applied to said presser bar.
2 more elements
Dependencies are inferred from the claim text.