CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority under Article 8 of the Patent Cooperation Treaty to German Utility Model Application No. 20 2015 007 098.1, having a filing date of October 10, 2015, the entire disclosure of which is hereby incorporated herein by reference.

DESCRIPTION

The invention comprises of a hybrid lead-free electrical glass solder connection element which can be soldered or bonded to appropriate contact surfaces of

windowpanes, glass panels or composite windowpanes.

The special feature of this lead-free electrical glass solder connection element is that, in contrast to the connections currently in use, it has the advantage of reducing the mechanical tensions incurred at the interfaces between the connection element and the glass which are caused by the different thermal expansion coefficients of the materials used, with simultaneously high electrical conductivity.

Conventional lead-free electrical glass solder connection elements comprise either of copper or brass materials and feature a high to extremely-high electrical conductivity corresponding to the material, but also a relatively high thermal expansion coefficient compared to glass, which then causes increased mechanical tension at the interface between the connection element and the glass. Relief is provided in particular by means of indium or bismuth-based solders which, thanks to their special material characteristics, compensate for tensions between the connection element and the glass, or, in the case of bismuth, display inverse expansion behaviour on cooling, which however requires compromises to be made in the temperature application range, as these melt in a lower temperature range (approx. 110°C to 150°C) than the conventional plumbiferous alloys (approx. 180°C to 250°C). Other conventional lead-free electrical glass solder connection elements, on the other hand, comprise of a combination of steel and copper materials or steel and brass materials (in which the steel section preferably contacts the glass as a bridge due to the lower thermal expansion coefficient compared to copper or brass) or are completely manufactured from steel. The current is conducted to the bridge via a flat plug contact, normally a reed, either by means of a flexible braid or a wire. In this process, especially low-expansion steels are used and are combined with a multitude of solder alloys, but they have the major disadvantage inherent in steels of multiple increases in the specific electrical resistance value (a factor of 6 to 40 and more) compared to copper or brass. This is especially disadvantageous if the glass connections should conduct high electrical capacities onto the windowpane or the composite windowpane-, for example as is usually required for heating panels. Coating of the steels with strongly electrically-conductive materials, for example silver, also does not help significantly, because although the coatings can increase the electrical conductivity somewhat, the required economic efficiency would not permit sufficiently-large cross-sections, and also the application of thicker layers of silver would counteract the advantages of the steel with regard to the thermal expansion coefficients.

Typically, hybrid lead-free electrical solder connection elements can be designed in two versions.

Version 1 consists of a bridge and an electrically functional element; in the simplest case, a conductor with a plug contact which is attached to this bridge.

Version 2 consists of a bridge and an electrically functional element; in the simplest case, a conductor and a screw contact.

Key for Figure 3.)

Lead-free hybrid solder connection, schematic

1- Bridge

2- Conductor with optional insulation

3- Plug contact Key for Figure 2.)

Bridge of hybrid solder connection from the side 1- Solder deposit with optional flux

2- Electrically strongly-conductive material, preferably copper or brass

3- Low-expansion steel alloy

4- Optional surface coating, such as silver, nickel or similar Key for Figure 3.)

Version 1 hybrid lead-free electrical glass solder connection

1 - Solder contact, preferably designed as a bridge

2 - Conductor

3 - Electrical functional unit (e.g. solenoid, filter, electronics)

4 - Plug

Key for Figure 4.)

Version 2 hybrid lead-free electrical glass solder connection

1 - Solder contact, preferably designed as a bridge

2 - Conductor

3 - Electrical functional unit (e.g. solenoid, filter, electronics)

4 - Screw connection