Replaceable Punch Tip Assembly for Fast Tool-Free Changeover

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Solution Overview

Problem

The existing punch tool assemblies in metalworking machines require frequent replacement of worn-out punch tips, leading to increased downtime and costs due to complex and inefficient replacement processes.

Innovation Solution

A punch assembly with a replaceable punch tip that can be easily engaged and disengaged from the punch body using a pivot latch mechanism, allowing for manual operation without tools, and featuring axial engagement between the punch tip and body, enabling quick replacement and alignment adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the entire punch is made of high-grade material and used repeatedly, then the punch can withstand compressive and tension loads, but the punch point becomes worn and requires replacement of the entire long punch, increasing downtime and cost

Engineering Contradiction:
Improvepunch strengthVSAvoidreplacement downtime
Core Design Contradiction:
StrengthVSLoss of time

Solution Approach 1:

The punch is divided into two segments: a reusable punch body made of standard material and a replaceable punch tip made of high-grade material. The punch tip can be detached and replaced independently when worn, eliminating the need to replace the entire punch assembly. This segmentation allows the expensive high-grade material to be concentrated only where needed (at the wear point) while reducing overall replacement time and cost.

Inventive Principle:
Principle #1Segmentation

2Loss of time

If a replaceable punch tip design is implemented, then replacement time and cost are reduced, but the coupling mechanism between punch tip and body adds device complexity

Engineering Contradiction:
Improvereplacement downtimeVSAvoidcoupling mechanism complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The coupling between punch tip and punch body is achieved through a simple interference fit with a slight taper, eliminating the need for complex threading, locking mechanisms, or specialized tooling. The tip is inserted axially and secured by friction and geometric constraints, allowing tool-less manual installation and removal. This mechanical substitution simplifies the coupling mechanism while enabling rapid replacement.

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

3Length of moving object

If the punch tip is made shorter and made from expensive high-grade material, then material cost for the tip is reduced and performance is improved, but the coupling mechanism must manage compressive and tension loads effectively

Engineering Contradiction:
Improvepunch tip lengthVSAvoidcoupling strength
Core Design Contradiction:
Length of moving objectVSStrength

Solution Approach 1:

The punch tip is designed with a slight taper on its insertion surface, which creates a self-centering and self-locking effect during insertion. The taper angle is optimized to generate sufficient radial friction force to hold the tip in place under both compressive and tension loads. This preliminary geometric configuration ensures proper load management without requiring additional active locking mechanisms.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3256271B1Punch assembly with replaceable punch tip
Publication Date: 2024.07.10 MATE PRECISION TECH INC
  • EP3256271B1 patent drawingFigure 1
  • EP3256271B1 patent drawingFigure 2
  • EP3256271B1 patent drawingFigure 3A~3B

AI summary

A punch system (10) or assembly includes a punch body (12) and a punch tip (14) or insert with a working end (15) and a stem (44) configured for selective engagement and disengagement within a cavity (54) in the punch body (12). A latch mechanism (50) which can be operated without tools is configured to engage the punch tip stem (44) within the axial cavity (54) in a closed position, and to disengage the punch tip (14) from the punch body (12) in an open position.