Connecting Terminal With Nested Clamping Spring And Arrester Bar

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Solution Overview

Problem

Existing connecting terminals for electrical conductors require significant space due to the arrangement of contact springs and lack protection against overstretching when releasing conductors.

Innovation Solution

The clamping spring is accommodated within the U-profile of the contact element, with an arrester bar serving as a dead stop to prevent overstretching, and the housing design includes a supporting wall and latching mechanism for secure fixation, allowing for a compact and protected terminal design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the clamping spring is arranged outside the U-profile of the contact element, then the clamping spring has sufficient space for operation, but the connecting terminal occupies more space and becomes less compact

Engineering Contradiction:
Improvevolume of connecting terminalVSAvoidoperation space for clamping spring
Core Design Contradiction:
Volume of moving objectVSEase of operation

Solution Approach 1:

The clamping spring is nested within the U-profile of the contact element, with the spring positioned inside the hollow space of the U-shaped contact element. This nesting arrangement allows the clamping spring to operate within the existing structure without requiring additional external space, thereby achieving a compact connecting terminal design while maintaining sufficient operation space for the spring's clamping and releasing functions

Inventive Principle:
Principle #7Nested doll (Nesting)

2Ease of operation

If the clamping spring is allowed to extend freely during conductor release, then the conductor can be easily released, but the clamping spring is subjected to overstretching and potential damage

Engineering Contradiction:
Improveease of conductor releaseVSAvoidprotection against overstretching
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The arrester bar is pre-positioned within the U-profile to establish a predetermined limit for the clamping spring's extension. Before the clamping spring can be overstretched during conductor release, it encounters the arrester bar which stops its movement in advance. This preliminary positioning of the stop mechanism prevents excessive extension and potential damage to the spring while still allowing sufficient travel for easy conductor release

Inventive Principle:
Principle #10Preliminary action

3Reliability

If a separate dead stop mechanism is added to protect the clamping spring, then the spring is protected against overstretching, but the device complexity and manufacturing cost increase

Engineering Contradiction:
Improveprotection against overstretchingVSAvoidcomplexity of dead stop mechanism
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The arrester bar is merged with the housing structure, forming an integrated component where the dead stop function is combined with the existing housing elements. Instead of adding a separate, independent dead stop mechanism, the arrester bar is designed as part of the housing assembly, thereby providing overstretching protection for the clamping spring while avoiding increased device complexity and manufacturing cost

Inventive Principle:
Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution achieves a compact terminal design while protecting the clamping spring from overload, ensuring reliable and efficient electrical connections with easy access for conductor insertion.

Implementation Method 1

a substantially U-shaped clamping spring, in the form of a leaf spring, which keeps the conductor in electrical and mechanical connection with the contact element

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2738879B1Connecting terminal
Publication Date: 2019.07.03 ABB AG(DE)
  • EP2738879B1 patent drawingFigure 1
  • EP2738879B1 patent drawingFigure 2
  • EP2738879B1 patent drawingFigure 3a~3b

AI summary

The invention is about a connecting terminal (3) for electrical conductors, having a contact element (40) substantially in the form of a U-profile, provided for the purpose of electrically contacting the conductor, having a substantially U-shaped clamping spring (41), in the form of a leaf spring, which keeps the conductor in electrical and mechanical connection with the contact element (40), and having an insulating housing (4) which accommodates the contact element (40) and the clamping spring (41), said housing (4) having an insertion side (60), a mounting side (61), a top side (62), a bottom side (63), and at the insertion side (60) at least one insertion opening (42) for the conductor, said contact element (40) having a first profile section (43) possessing substantially a L-shape with a first and a second limb (46, 47) and with a plug-in opening (44) which is aligned with respect to the insertion opening (42), and with a second, substantially flat profile section (45), whereby the clamping spring (41) has a support limb (48) being connected to the second profile section (45) of the contact element (40), and a clamping limb (49) which is configured to be positioned with its free end against a conductor inserted into the plug-in opening (44) to press it against the first limb (46) of the contact element (40) and to be pushed towards the support limb (48) for releasing the conductor from the first limb (46), whereby the clamping spring (41) is accommodated within the U-profile of the contact element (40), that the U-shape of the clamping spring (41) opens towards the mounting side of the housing (4), and that an arrester bar (51) extends from the inner wall of the mounting side (61) into the open space between the support limb (48) and the clamping limb (49) of the clamping spring (41) to serve as a dead stop for the bending movement of the clamping limb (49) when releasing the conductor from the first limb (46).