Knife mechanism drive for a buttonhole sewing machine

US5692447A · kind A · utility

Assignee

• AMF Reece, Inc. · US

Inventors

• Rudy Papajewski, deceased · Blankenloch, DE
• Gerd Papajewski · Blankenloch, DE

Key dates

• Filing date: Sep 24, 1996
• Grant date: Dec 2, 1997
• Expiry date: Sep 24, 2016

Classification

• Technology area (CPC D): Textiles; Paper
• CPC primary: D05B3/06
• WIPO field: Textile and paper machines
• WIPO sector: Mechanical engineering

Abstract

A grooved barrel cam is mounted on a needle bar drive shaft. As the last step, after stitching is completed and power is removed, an engaging arm inserts a follower pin into the cam. A knife cam follower lever drives a knife drive shaft and a knife driving lever. The knife driving lever drives a knife holder downward. A connector at a middle of the knife holder maintains the holder vertical. A knife is secured at the bottom of the knife holder. The cam and a tension spring angularly return the cam follower lever, the shaft and the knife lever and lift the holder, when the cut has been completed. A compression spring around the knife drive shaft moves the follower away from the cam once the engaging arm has released the follower. Engaging the knife cam follower and operating the knife driving mechanism on the last revolution after the clutch is released helps exhaust the kinetic energy of the sewing machine before bringing the machine to a stop.