Cordless Handheld Punch Tool With Rotatable Die for Mid-Sheet Cutting

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Solution Overview

Problem

Handheld reciprocating punch tools, or nibblers, generate sharp metal fragments during cutting, are limited by the need for AC power or compressed air, and cannot initiate cuts in the middle of a sheet or on closed ducts due to their design.

Innovation Solution

A handheld punch tool with a rotatable die holder, an asymmetric punch element, and an electric motor with a high-inertia fan or flywheel for improved cutting efficiency and maneuverability, allowing for adjustable cutting depths and the ability to cut through sheet metal without a power cord or air hose.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If AC power or compressed air is used to power the nibbler, then the tool has sufficient power for cutting, but the power cord or air hose limits access and maneuverability

Engineering Contradiction:

Improvecutting powerVSAvoidmaneuverability

Core Design Contradiction:

PowerVSEase of operation

Solution Approach 1:

The patent replaces the traditional AC power or compressed air system with a battery-powered electric motor system. This substitution eliminates the need for power cords or air hoses, providing cordless operation while maintaining sufficient cutting power through optimized motor selection and battery integration.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The tool integrates its own power source (battery and motor system) within the handheld unit, making it self-sufficient and independent of external power supplies. This self-contained design enables complete mobility and access to confined spaces without requiring external infrastructure.

Inventive Principle:

Principle #25Self-service

2Device complexity

If a traditional punch design is used, then the structure is simple, but the tool can only begin a cut on an edge and not in the middle of a sheet or on a closed duct

Engineering Contradiction:

Improvestructural simplicityVSAvoidcut initiation capability

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The cutting system is segmented into separate punch and die components that can operate in a nested configuration. The punch element can be positioned and activated independently within the die holder, enabling cut initiation at any location on the workpiece rather than requiring edge access. This modular segmentation provides the mechanical complexity needed for versatile cutting while maintaining operational simplicity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent transitions from edge-based linear cutting to point-based omnidirectional cutting capability. By allowing the punch to engage the workpiece from any position and orientation, the tool adds dimensional freedom to the cutting operation, enabling starts in the middle of sheets and on closed ducts rather than being constrained to edge-only initiation.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Productivity

If a reciprocating punch mechanism is used, then cutting action is achieved, but numerous sharp fragments are ejected during operation

Engineering Contradiction:

Improvecutting speedVSAvoidfragment sharpness and quantity

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent transforms the harmful ejection of sharp fragments into a controlled chip formation process. By optimizing the punch-die geometry and material flow characteristics, the cutting action produces compact, less hazardous chips that are easier to manage. The reciprocating motion is refined to minimize fragment dispersion while maintaining cutting efficiency, converting the previously harmful fragment ejection into a more controlled material removal process.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 tool effectively reduces fragment generation, enhances cutting precision and power efficiency, and enables cuts to be started anywhere on a sheet metal, improving user access and control.

Implementation Method 1

a fan coupled to the motor shaft for co-rotation therewith. The fan has a rotational inertia of at least 50% of a total rotational inertia of a rotating assembly comprising the fan, the motor shaft, and all other components of the handheld punch tool driven by the electric motor for rotation about the motor axis

Methodology Applied

Scientific EffectForced Convection: Forced Convection

Implementation Method 2

Methodology Applied

Scientific EffectRotational Inertia: Moment of Inertia

Data Source

PatentUS11820038B2Handheld punch tool

Publication Date: 2023.11.21 MILWAUKEE ELECTRIC TOOL CORP

AI summary

A handheld punch tool includes a housing, a die holder coupled to the housing, a die supported by the die holder, the die and the die holder defining a feed slot therebetween for receiving a workpiece to be cut, and a punch configured to reciprocate within the die holder, with a main body defining a first longitudinal axis extending centrally through the main body and a punch element extending from the main body along a second longitudinal axis parallel to the first longitudinal axis. The punch element is configured to cut a first distance into the workpiece per stroke of the punch when the feed slot faces a first side of the punch and to cut a second distance into the workpiece per stroke when the feed slot faces a second side of the punch opposite the first side. The first distance is greater than the second distance.