US 4,643,112 AGranted

Device for braking the limbs of needle threads in oscillating hook type sewing machines

AssigneeFritz Gegauf Aktiengesellschaft Bernina-Nahmaschinenfabrik

InventorsGregor Sidler, Jakob Rickenbach

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Abstract

One limb of each loop which is formed by the needle thread in an oscillating hook type sewing machine is temporarily in contact with the loop-engaging member of a braking device whose torsion spring is non-rotatably installed in the hollow mandrel of the hook. The loop-engaging member is turned by successive loops from a starting position, relative to the hook and against the opposition of the spring so that it tensions the loop while the latter is raised by the takeup lever. The spring thereupon rapidly returns the loop-engaging member to its starting position. The loop-engaging member is integral with a loop catcher which intercepts the loop when the latter is cast off the hook and which ensures that the loop comes in contact with the loop-engaging member.

Claims17

Dependent claims

A sewing machine comprising a substantially vertically reciprocable needle for the upper thread;

means for reciprocating said needle;
a shuttle hook mounted for oscillatory movement in a substantially vertical plane about a predetermined axis;
means for oscillating said hook so that the hook and the needle cooperate in converting the upper thread into a series of loops each having a plurality of limbs;
and means for temporarily braking at least one limb of each loop, including a loop-engaging member movable by successive loops with reference to said hook in a second plane which is at least substantially parallel to said vertical plane from a first position to a second position in which a loop is cast off said member as a result of upward movement of the engaged portion of the loop;
and means for yieldably biasing said member to said first position.

2 more elements

Dependencies are inferred from the claim text.