Inflatable or twistable tubes for embroidery hoop fabric tensioning

US5129171A · kind A · utility

Assignee

• PFAFF INDUSTRIES MASCHINEN AG · DE

Inventors

• Conrad Arbter · Ribnitz-Damgarten, DE
• Rolf Mahling · Medebach, DE

Key dates

• Filing date: Dec 17, 1990
• Grant date: Jul 14, 1992
• Expiry date: Dec 17, 2010

Classification

• Technology area (CPC D): Textiles; Paper
• CPC primary: D05C9/04
• WIPO field: Textile and paper machines
• WIPO sector: Mechanical engineering

Abstract

A device for zone-by-zone tensioning of a flat material, especially an embroidery hoop. According to one possible solution, tensioning and clamping are brought about by a change in the circumferential length of a tensioning member that can be filled, by a gas or a fluid and another solution brings this about by twisting a tensioning member. To generate a strong tensioning force in the material, it is proposed in the first solution that the tensioning member be designed as a crease-free tube with a body. By selecting a cord angle of the body, tensioning can be achieved by increasing or decreasing the pressure and by increasing or decreasing the circumferential length. According to another solution, the tensioning member is designed as a torsion body that can be twisted in itself, preferably as a reinforced hollow body, which may also form a closed ring. To increase the tensioning force without unduly stressing the material, the device is designed with a rigid outer ring and a twistable inner ring. By providing the tube that can be filled by a gas or a fluid with strength-ensuring members of limited extensibility in certain areas according to the first possible solution, twisting in …