One-Piece Lock Striker Cold Upset Forming

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Solution Overview

Problem

The existing methods for producing lock holders, such as those used in motor vehicle locking systems, face challenges with high forming forces and tool stresses, requiring large machines and resulting in material inefficiencies and complex post-processing steps.

Innovation Solution

A method involving cold upsetting of a metallic starting blank, where the blank is strain-hardened to form a one-piece lock holder with specific mechanical properties, reducing forming forces and enabling the use of lower-strength materials, and allowing for efficient production with smaller machines and minimal tool stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If cold extrusion or cold upsetting is used to massively reshape a starting blank, then a one-piece lock holder can be produced with improved mechanical properties, but high forming forces are required resulting in high tool stress

Engineering Contradiction:
Improvemechanical properties of lock holderVSAvoidtool stress
Core Design Contradiction:
StrengthVSStress or pressure

Solution Approach 1:

The starting blank is pre-shaped into a T-shaped semi-finished product with a bead of material positioned on the lock shackle leg before the main forming operation. This preliminary configuration allows the bead to act as a material reservoir during subsequent forming, reducing the need for high forming forces while still achieving the desired final shape and mechanical properties

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the physical state and configuration of the starting material by heating it to processing temperatures above the recrystallization temperature before forming. This thermal parameter change makes the material more formable, reducing the forming forces and tool stress required while still achieving the desired mechanical properties in the final lock holder

Inventive Principle:
Principle #35Parameter changes

2Shape

If hot forging with temperatures above recrystallization temperature is used, then the lock holder can be formed with complex shapes, but the process requires high energy input and complex heating/cooling cycles

Engineering Contradiction:
Improvecomplex geometry of lock holderVSAvoidenergy input for heating
Core Design Contradiction:
ShapeVSUse of energy by moving object

Solution Approach 1:

Instead of heating the entire starting blank uniformly to high temperatures, the invention applies localized heating or heating only for the duration necessary to achieve the required formability. The bead of material is positioned to provide localized material flow where needed, reducing the overall energy input required while still achieving complex shapes

Inventive Principle:
Principle #16Partial or excessive action

3Productivity

If massive forming into a T-shaped semi-finished product is used, then time-consuming post-processing can be saved, but high forming forces are required

Engineering Contradiction:
Improveproduction time efficiencyVSAvoidforming force
Core Design Contradiction:
ProductivityVSForce

Solution Approach 1:

The T-shaped semi-finished product with the bead of material is created as a preliminary configuration that inherently contains the material needed for the final forming operation. This preliminary action eliminates the need for additional material addition or complex post-processing, while the bead configuration reduces the forming force required by providing material flow paths that reduce resistance during forming

Inventive Principle:
Principle #10Preliminary action

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 method results in lock holders with optimized strength and fatigue properties, reduced production costs, and improved material utilization, while minimizing tool stress and enabling the use of lower-strength starting materials, achieving enhanced mechanical performance and efficient production.

Implementation Method 1

A method is proposed for producing a lock holder, in which a lock holder is formed from a starting blank essentially in the form of a block or cylinder by cold upsetting in such a way that the lock holder is strain-hardened

Methodology Applied
Scientific EffectCold-forming: Cold-forming

Implementation Method 2

The forming process through plastic change of a given solid starting blank is fundamentally associated with the problem that high forming forces are required

Methodology Applied
Scientific EffectPlasticity: Plasticity

Data Source

PatentEP2893107B1Method for producing a one-piece lock striker
Publication Date: 2018.06.20 KIEKERT AG
  • EP2893107B1 patent drawingFigure 1
  • EP2893107B1 patent drawingFigure 2a~3b

AI summary

The invention relates to a method for producing a one-piece lock striker and to a lock striker produced according to said method. The lock striker (1) comprises a base plate (1) and a lock bracket (3). A metal starter blank (11) is formed into a lock striker by cold forming, in particular by cold upsetting. The starter blank (11) is substantially block-shaped or cylindrical and is formed in such a way that the lock striker (1) becomes strain-hardened.