Lever Key Blank Stacking Formations for Jam-Free Handling

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Solution Overview

Problem

Lever key blanks tend to incline and jam when stacked due to their cylindrical profile, causing handling difficulties in key cutting machines.

Innovation Solution

Incorporating non-rectangular shank cross-sections with parallel engagement surfaces on the lever key blanks, such as on the collar or head, to maintain alignment and prevent jamming.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If lever key blanks have a cylindrical shank profile, then the shank provides smooth rotational support and strength, but the blanks tend to incline and slide past one another when stacked

Engineering Contradiction:
Improveshank strengthVSAvoidstacking stability
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The shank cross-section is changed from circular to non-circular (rectangular, square, or polygonal), creating an asymmetric shape that prevents rotation and sliding when stacked. This asymmetric geometry allows the blanks to stack vertically without inclining, while still providing sufficient strength for lock operation.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The invention adds a new dimension to the stacking stability problem by introducing engagement surfaces that extend beyond the collar in the vertical direction. These surfaces create mechanical interlocking between stacked blanks, transforming the stacking behavior from unstable sliding to stable vertical alignment.

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

2Stability of the object's composition

If lever key blanks have a cylindrical collar, then the collar provides a stable abutment surface, but the blanks still jam in magazines and cartridges when stacked

Engineering Contradiction:
Improvecollar abutment stabilityVSAvoidhandling ease
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The collar cross-section is changed from circular to non-circular, creating an asymmetric shape with engagement surfaces that extend beyond the collar. This prevents the blanks from rotating or sliding when stacked in magazines, eliminating jamming while maintaining the abutment function.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The engagement surfaces act as an intermediary mechanical feature between the collar and the stacking blanks. These surfaces extend beyond the collar to create a bridging structure that prevents direct contact and sliding between adjacent blanks, thereby preventing jamming while preserving the collar's abutment function.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Quantity of substance

If lever key blanks are stacked in a magazine, then multiple blanks are available for cutting, but the blanks become jammed due to inclined stacking

Engineering Contradiction:
Improvenumber of blanksVSAvoidcutting efficiency
Core Design Contradiction:
Quantity of substanceVSProductivity

Solution Approach 1:

The non-circular shank and collar cross-sections create asymmetric engagement surfaces that force the blanks to stack vertically in a fixed orientation. This prevents inclining and jamming in the magazine, allowing all blanks to be readily accessible for cutting operations and maintaining high productivity.

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP3396085B1keys
Publication Date: 2025.09.24 ICONX LTD
  • EP3396085B1 patent drawingFigure 1
  • EP3396085B1 patent drawingFigure 2
  • EP3396085B1 patent drawingFigure 3~4

AI summary

A lever key blank 10 including stacking formations which define a spaced pair of parallel engagement surfaces 30. The parallel engagement surfaces 30 extend beyond or at least as far as the remainder of lever key blank 10 in a direction perpendicular to the surfaces 30.