Thermal fuse and method for its activation

US5612662A · kind A · utility

Assignee

• Siemens Aktiengesellschaft · DE

Inventors

• Karl-Gerd Drekmeier · Unterhaching, DE
• Gerhard Winter · Dossenheim, DE

Key dates

• Filing date: Feb 7, 1995
• Grant date: Mar 18, 1997
• Expiry date: Feb 7, 2015

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T29/49107
• WIPO field: Electrical machinery, apparatus, energy
• WIPO sector: Electrical engineering

Abstract

A thermal fuse includes a leaf spring formed of a narrow sheet metal strip. The leaf spring has ends and at least two contact points at the ends. At least one of the contact points is a soldering point for connection with corresponding circuit contacts of a circuit substrate. The leaf spring has at least one spring arm interconnecting the contact points. The spring arm has a roof-shaped deformation in the vicinity of one contact point. The spring arm has a flat and elongated spring segment with a transition adjoining the deformation and a transition extending to the other contact point. The spring segment is bending resistant in the vicinities of the transitions, for transforming a compressive deformation applied to the roof-shaped deformation into a lateral movement and into an arching of the spring segment, with both ends of the leaf spring attached to the circuit substrate without pretensioning. A method for activation of the thermal fuse includes placing the contact points of the leaf springs free of tension on the circuit contacts, soldering the contact points to the circuit contacts, and compressively deforming the roof-shaped deformation after the soldering for creating an a…