Terminal Block Lever Offset for Back-to-Back Access

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Solution Overview

Problem

Existing quick-connect terminal blocks with levers face difficulties in operation, especially when mounted side by side in restricted spaces, such as flush-mounting boxes, due to the proximity of gripping zones and the need for tools to access and manipulate the levers effectively.

Innovation Solution

The terminal block design features levers with a gripping zone offset laterally when in the closed position, allowing easier access and manipulation, and a double-switch system where terminal blocks are mounted back-to-back with offset gripping zones, facilitating access to the levers and optimizing the size and ease of use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If two terminal blocks are mounted back-to-back in a flush-mounting box with levers aligned with cable insertion points, then the lever mechanism can effectively open and close jaws to secure cables, but the gripping areas of the levers become inaccessible and difficult to operate without tools

Engineering Contradiction:
Improvelever locking mechanismVSAvoidlever accessibility
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent repositions the lever gripping area from a location aligned with the cable insertion point to a location offset in a different spatial dimension (perpendicular to the lever arm). This dimensional shift allows the gripping area to be accessible from the front of the terminal block while the lever mechanism remains functional for securing cables from the rear, resolving the accessibility conflict in back-to-back mounting configurations.

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

Solution Approach 2:

The patent introduces asymmetric positioning where the lever gripping area is deliberately offset from the symmetric alignment with the cable insertion point. This asymmetric arrangement creates an ergonomic grip zone that is accessible from the front, while the lever's pivot point and jaw mechanism remain positioned to effectively secure cables from the rear, enabling tool-free operation in compact installations.

Inventive Principle:
Principle #4Asymmetry

2Force

If the lever gripping area is positioned at the level of the face opposite to the cable insertion side, then the lever can effectively act on the spring-loaded tab, but the space between gripping areas of adjacent terminal blocks becomes too limited for tool-free operation

Engineering Contradiction:
Improvelever actuation forceVSAvoidgripping area accessibility
Core Design Contradiction:
ForceVSEase of operation

Solution Approach 1:

The patent moves the gripping area to a different spatial dimension - positioned on the front face of the terminal block rather than on the rear face opposite the cable insertion. This repositioning creates sufficient clearance between gripping areas of adjacent terminal blocks mounted back-to-back, enabling easy finger access and tool-free operation while preserving the lever's mechanical advantage for actuating the spring-loaded tab.

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

Solution Approach 2:

The patent introduces the offset gripping area as an intermediary element that mediates between the user's finger and the lever mechanism. This gripping area serves as a leverage point that transmits user force to the lever arm, which in turn actuates the spring-loaded tab, enabling effective cable securing while maintaining accessibility in compact configurations.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Power

If the lever pivot axis is positioned directly above the cable insertion area, then the lever mechanism provides effective mechanical advantage, but the gripping areas of back-to-back mounted terminal blocks face each other with insufficient space for operation

Engineering Contradiction:
Improvelever mechanical advantageVSAvoidlever manipulation space
Core Design Contradiction:
PowerVSEase of operation

Solution Approach 1:

The patent repositions the gripping area from a location on the rear face to a location on the front face of the terminal block, creating spatial separation between the gripping areas of back-to-back mounted terminal blocks. This dimensional repositioning maintains adequate clearance for finger access and lever manipulation while preserving the pivot axis alignment for effective mechanical advantage in cable securing operations.

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

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 design enhances the accessibility and usability of the terminal blocks, allowing for easier handling and operation of the levers without the need for tools, even in compact configurations, thereby simplifying the connection and disconnection of electrical cables.

Implementation Method 1

a bent spring-loaded tab... The spring-loaded tab then locks the wire between an inner metal face of the terminal block and the spring-loaded tab

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

When the lever corresponding to the first hole is raised, a force is applied to the spring-loaded tab, and the hole is opened to allow insertion of the stripped end of the electrical wire

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentEP3291376B1Electrical connection block and double switch system comprising two such blocks
Publication Date: 2020.09.23 SOMFY ACTIVITES SA
  • EP3291376B1 patent drawingFigure 1~2
  • EP3291376B1 patent drawingFigure 3~4
  • EP3291376B1 patent drawingFigure 5~6

AI summary

This terminal block (2) for connecting electrical cables (C2, C4, C6) comprises an electrically insulating housing (4) and at least one lever (12) hinged to the housing about a pivot axis (X12) and comprising an elongated lever arm (124) extending along a longitudinal axis (A12), between the pivot axis and a free end of the lever arm. A lateral face (2C) of the terminal block is provided with at least one hole (10) for inserting a stripped end of an electrical cable along a cable insertion axis (Y10), this hole (10) opening into an internal volume of the housing (4).The pivoting of the lever allows it to move from a first position, referred to as the open position, in which the lever permits the insertion of a stripped end of an electrical cable (C2) through the insertion hole (10) on the side face (2C) into the internal volume, to a second position, referred to as the closed position, in which the lever prevents the previously inserted stripped end of the electrical cable from being withdrawn from the internal volume of the housing. The lever (12) further includes a gripping area (126) positioned at the free end of the lever arm (124). When the lever is in its second position, referred to as the closed position, the gripping area (126) is offset laterally, parallel to the pivot axis (X12), with respect to an axis (Y22) radial to the pivot axis and passing through an intersection point (P12) between the pivot axis (X12) and the longitudinal axis of the arm (A12).