Ball-Lock Stripper Unit With Precision Threaded Plug

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Solution Overview

Problem

Existing punch and die systems face issues with work pieces adhering during high-speed manufacturing, with metal strippers interfering with punch retainer placement and polyurethane strippers requiring separate retainers for accurate positioning.

Innovation Solution

A compact stripper unit featuring a precision threaded plug that preloads a mechanical die spring and locates on a ball-lock punch retainer, providing accurate alignment and self-contained operation, eliminating external force transfer and component loss risks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If metal strippers are used to prevent work piece drag on the punch, then stripping performance is improved, but the stripper units extend over the sides of the punch retainers and interfere with close placement of punch retainers

Engineering Contradiction:
Improvestripping performanceVSAvoidstripper unit dimensions
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the stripper unit with the punch retainer into a single integrated assembly. The stripper unit is positioned within the punch retainer structure itself, eliminating the need for separate external stripper components that would extend beyond the retainer boundaries. This merging resolves the contradiction by maintaining stripping functionality while preventing interference with punch retainer placement.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The stripper unit is nested within the punch retainer structure. The stripper component is housed inside the retainer body, with only the necessary stripping surfaces exposed. This nesting approach allows the stripper to perform its function of preventing work piece drag while remaining compact and not extending over the sides of the punch retainer.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If polyurethane strippers are used to prevent work piece drag, then stripping performance is improved, but separate metal retainers are required to accurately position the strippers on the punch retainers

Engineering Contradiction:
Improvestripping performanceVSAvoidretainer structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent integrates the positioning function into the unified stripper-punch retainer assembly. The stripper is accurately positioned through features built into the integrated structure, such as recesses, tabs, or machined surfaces that provide precise location without requiring separate positioning retainers. This eliminates the need for additional metal retainers while maintaining accurate stripper positioning.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The punch retainer structure is designed to serve multiple functions simultaneously: it provides structural support, positions the stripper accurately, and integrates the stripping function. This multi-functional design eliminates the need for separate dedicated positioning retainers, reducing overall device complexity while maintaining positioning accuracy.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Device complexity

If a compact stripper unit design is implemented, then device complexity is reduced and punch retainer placement is improved, but accurate positioning and preloading of the die spring must be achieved

Engineering Contradiction:
Improvestripper unit structureVSAvoidpositioning accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The die spring is preloaded during the assembly process through the compact stripper unit design. The structure incorporates features such as preloaded spring seats, precision-machined locating surfaces, and assembly sequences that ensure accurate positioning and proper spring preload are achieved before the unit is installed. This preliminary action ensures manufacturing precision is maintained despite the compact design.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces complex external positioning mechanisms with precision machining and inherent geometric constraints. Instead of using separate mechanical positioning devices, the compact design relies on precisely machined surfaces, fitted joints, and geometric interlocking features to achieve accurate positioning, substituting mechanical complexity with manufacturing precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Adaptability or versatility

If the stripper unit is designed for universal compatibility with standard ball-lock punch retainers, then adaptability is improved, but the design must accommodate various retainer configurations

Engineering Contradiction:
Improveretainer compatibilityVSAvoiddesign flexibility
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The stripper unit is designed with universal features that allow it to accommodate various ball-lock punch retainer configurations. This includes standardized mounting interfaces, adjustable positioning features, and design elements that can adapt to different retainer sizes and geometries. The unit maintains its compact form while incorporating flexible mounting options that ensure compatibility across multiple retainer types without requiring complex customization for each configuration.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

The solution ensures reliable, long-lasting stripping performance with universal compatibility for standard ball-lock punch retainers, enhancing manufacturing efficiency and safety by isolating die spring forces and preventing overloading, while facilitating easy assembly and disassembly.

Implementation Method 1

a mechanical die spring engaging the stripper within the hollow body

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a precision threaded plug received into a precision threaded hole in the bottom of the hollow body and engaging the die spring

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentEP1922191B1Stripper unit for a punch retainer
Publication Date: 2013.02.20 MOELLERING DAVID J
  • EP1922191B1 patent drawingFigure 1~4
  • EP1922191B1 patent drawingFigure 5~7

AI summary

A stripper unit incorporates a precision threaded plug that preloads a mechanical die spring that, in turn, preloads the movable or traveling stripper adjacent the punch tip. The precision threaded plug simultaneously accurately locates the stripper unit on a commercially available ball-lock punch retainer. The stripper unit is entirely self-contained on the face of the ball-lock punch retainer, thus minimizing the space required on the press platen.