Electric Contact Primary Lance Housing Projection Design

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Solution Overview

Problem

Existing electrical contacts for plug connections, particularly for printed circuit boards, face issues with low holding force of the primary lance in the contact chamber, leading to easy displacement under high loads and difficulties during disassembly due to sharp edges.

Innovation Solution

The primary lance is overlapped by a housing projection, providing additional support and preventing outward push, while maintaining current transmission and reducing snagging during processing, with a bent free end preventing the lance from getting stuck during disassembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the primary lance protrudes outwards to hold back the contact, then the holding force is improved, but the lance can be pushed outwards easily under high load

Engineering Contradiction:
Improveholding force of primary lanceVSAvoidresistance to outward push under load
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The patent adds a longitudinal dimension to the primary lance structure by creating an overlapping arrangement where one lance extends beyond and overlaps another lance. This dimensional addition provides both the necessary protrusion for holding force and the overlapping support to prevent outward pushing under load, resolving the contradiction between needing protrusion and preventing displacement.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Force

If the free end of the primary lance is sharp-edged for secure holding, then the holding force is improved, but the contact gets caught during disassembly

Engineering Contradiction:
Improveholding force of primary lanceVSAvoidease of disassembly
Core Design Contradiction:
ForceVSEase of operation

Solution Approach 1:

The patent applies curvature to the free end of the primary lance, replacing the sharp edge with a rounded or bent configuration. This curved geometry maintains the ability to engage with and hold the contact securely while eliminating the snagging effect that occurs with sharp edges during disassembly operations, thus resolving the contradiction between secure holding and ease of removal.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Force

If the primary lance is deflected inwards to hold back the contact, then the holding force is improved, but the lance may get damaged during processing

Engineering Contradiction:
Improveholding force of primary lanceVSAvoidresistance to damage during processing
Core Design Contradiction:
ForceVSStrength

Solution Approach 1:

The patent implements a pre-deflected or pre-positioned primary lance configuration that is already oriented in the optimal holding position before final assembly. This preliminary positioning allows the lance to provide holding force through its geometric configuration rather than requiring significant deflection during operation, thereby maintaining its strength and resistance to damage during processing while still achieving the necessary holding function.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2514038B1Electric contact for plug connections
Publication Date: 2013.09.18 ROBERT BOSCH GMBH
  • EP2514038B1 patent drawingFigure 1a~1b
  • EP2514038B1 patent drawingFigure 2

AI summary

The invention relates to an electric contact (1) for plug connections, in particular for directly contacting contact surfaces (2) of a printed circuit board (3), comprising a contact housing (4) that has a primary lance (6), which protrudes outwardly beyond the contact housing (4) counter to the insertion direction (5) and can be deflected inwardly, for retaining the contact (1) inserted into a contact chamber of a mating connector. According to the invention the primary lance (6) has a free lance end (8) that is offset inwardly in relation to the lance section (7) thereof protruding outwardly and that extends counter to the insertion direction (5), a housing stop (9) of the contact housing (4) extending over said free lance end.