Freely revolving looper for double lockstitch sewing machines

US4572091A · kind A · utility

Assignee

• Pfaff AG · DE

Inventors

• Kurt Gustmann · Kaiserslautern, DE
• Siegard Brandt · Stelzenberg, DE
• Ludwig Sourisseaux · Ramstein-Miesenbach, DE

Key dates

• Filing date: Nov 18, 1983
• Grant date: Feb 25, 1986
• Expiry date: Nov 18, 2003

Classification

• Technology area (CPC D): Textiles; Paper
• CPC primary: D05B57/14
• WIPO field: Textile and paper machines
• WIPO sector: Mechanical engineering

Abstract

A rotary hook for a sewing machine has a rotatable hook drive shaft driving a hook body in cooperation with a reciprocating needle which moves toward and away from the rotary hook. The hook body has a revolving rotary hook tip which is movable in a path relative to the needle and is engageable with the thread presented by the needle. The rotary hook includes a thread deflecting shoulder to enlarge the thread to form a needle thread loop, includes a case holder having an annular guide rib and a pin extending axially outwardly of the holder. A bobbin case has a central hollow sleeve into which the pin extends and a latch engageable with the pin to hold the case holder to the bobbin case. The case each holder and the bobbin case have a sidewall with interiors which are in substantial alignment. The bobbin case holder has a rearwall formed as a substantially truncated cone which is eccentric to the guide rib and the bobbin case has an annular sidewall and a frontwall have an arched mushroom shape. The bobbin case holder and the bobbin case are fitted together, not telescopingly, but on the pot-and-lid principle.