Thermal fuse

• US 8,633,795 B2
• Filed: 02/01/2008
• Issued: 01/21/2014
• Est. Priority Date: 03/26/2007
• Status: Expired due to Fees

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Knab, Norbert, Schulze-Icking-Konert, Georg, Mohr, Thomas, Kotthaus, Stefan, Haberl, Nikolas, Stampfer, Stefan, Mueller, Michael
• Primary Examiner(s): Vortman, Anatoly
• Application Number:
  US12/593,124
• Publication Number:
  US 20100109833A1
• Time in Patent Office: 2,181 Days
• Field of Search: 337/152, 337/159, 337/160, 337/180, 337/181, 337/290, 337/158, 337/296, 337/413, 296/23, 148/400, 420/561, 420/562, 420/559, 420/577
• US Class Current: 337/159
• CPC Class Codes: H01H 2037/763 the spring being a blade spring
• CPC Class Codes: H01H 37/761 with a fusible element forming part of the switched circuit H01H37/767 takes precedence
• CPC Class Codes: H05K 1/0293 Individual printed conductors which are adapted for modification, e.g. fusable or breakable conductors, printed switches
• CPC Class Codes: H05K 2201/10181 Fuse
• CPC Class Codes: H05K 3/202 using self-supporting metal foil pattern
• CPC Class Codes: Y10T 29/49107 Fuse making

Abstract

The invention relates to a thermal fuse in a circuit structure, particularly a punched grid, having a plurality of circuit areas, having the circuit structure with connections sites (9) and having a fusible element (3), which is electrically and mechanically connected to the connection sites (9) of the circuit structure, a material of the fusible element (3) having a melting point, in order to melt at an ambient temperature greater than the melting point, such that material of the fusible element (3) collects at the connection sites (9) and the electrical connection formed by the fusible element (3) breaks.

Claims

1. A thermal fuse in a circuit structure with several circuit areas with connections sites and a fusible element that is electrically and mechanically connected to the connection sites of a soldering flux core circuit structure, wherein a material of the fusible element has a melting temperature so that the material of the fusible element melts when an ambient temperature is higher than the melting temperature, and so that the material of the fusible element accumulates at the connections sites due to a surface tension and breaks the electrical connection that is created by the fusible element, wherein the connection sites are arranged at corresponding contact bridges of the circuit structure, wherein the circuit structure comprises at least one idle power section that does not contribute to current supply, the at least one idle power section positioned on a line arm section of the circuit structure which extends along a side of the corresponding contact bridges, wherein the at least one idle power sections are connected with conductor paths that lead to the corresponding contact bridges, the conductor paths arranged traversely to a connection direction of the fusible element, and wherein the circuit structure is surrounded by a sheathing, wherein the at least one idle power section is arranged and configured as a relief structure which ensures a fixing in the sheating, so that mechanical tensions are released by the relief structures to the sheathing.

2. The thermal fuse of claim 1, wherein the connection sites are separated at a distance from each other such that the melted material of the fusible element is electrically separated at the connection sites.

3. The thermal fuse of claim 1, wherein the fusible element is one of:

soldered;

welded; and

glued to the connection sites.

4. The thermal fuse of claim 1, wherein at least one of:

the fusible element is covered with a soldering flux; and

a soldering flux core is provided in the material of the fusible element or an interlayer between two layers of the material of the fusible element.

5. The thermal fuse of claim 1 wherein the circuit structure is embedded in a sheathing.

6. The thermal fuse of claim 1 wherein the circuit structure is a punched grid.