Rotary Power Tool Accessory With Threaded Blade Feed for Cutting Rods

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Solution Overview

Problem

Existing tools lack an efficient and convenient method for cutting elongated members like rods and tubular members, such as PVC pipes, using rotary power tools without requiring a dedicated cutting tool.

Innovation Solution

A power tool accessory with a housing, input shaft, threaded shaft, and blade holder that couples to a rotary power tool, allowing the blade to move axially to expose and retract from the workpiece holder, facilitating cutting by rotating the threaded shaft, which is driven by the power tool.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a dedicated cutting tool is used for cutting elongated members, then cutting performance and reliability are improved, but device complexity and cost increase

Engineering Contradiction:
Improvecutting performanceVSAvoidtool requirement
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies universality by enabling a rotary power tool to perform both drilling and cutting operations through a multi-functional accessory assembly. The accessory includes a blade holder with a cutting blade that can engage elongated members, allowing the same power tool to serve multiple purposes (drilling holes and cutting rods/pipes) without requiring separate dedicated tools, thus reducing device complexity while maintaining cutting reliability

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

Solution Approach 2:

The patent merges the cutting function with the existing rotary power tool system by integrating a blade holder, cutting blade, and workpiece holder into an accessory assembly that attaches to the power tool. This combination allows the drilling tool to simultaneously perform cutting operations, eliminating the need for separate cutting tools and simplifying the overall toolset required

Inventive Principle:
Principle #5Merging (Combining)

2Device complexity

If hand operated tools are used for cutting elongated members, then device complexity is reduced, but productivity and cutting efficiency deteriorate

Engineering Contradiction:
Improvetool structureVSAvoidcutting efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent replaces manual mechanical cutting operations with a power-driven system. The rotary power tool provides rotational motion that drives the cutting blade through the workpiece, substituting human physical effort with mechanical power. This maintains simple device structure while dramatically improving cutting efficiency and productivity through powered operation

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

Solution Approach 2:

The patent introduces dynamic motion control through the powered rotary mechanism. The cutting blade rotates at controlled speeds provided by the power tool, enabling efficient cutting through dynamic mechanical action rather than static manual effort. The workpiece holder also provides dynamic positioning to facilitate smooth cutting operations

Inventive Principle:
Principle #15Dynamics

3Productivity

If the blade is always exposed for cutting operations, then cutting speed is improved, but safety and risk of injury increase

Engineering Contradiction:
Improvecutting speedVSAvoidsafety risk
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies dynamics by making the blade exposure state changeable rather than fixed. The blade holder is designed to allow the cutting blade to be positioned in different states (exposed for cutting, retracted for safety) based on operational requirements. This dynamic positioning capability enables the blade to be exposed only when needed for cutting, maintaining cutting speed while reducing safety risks during non-cutting periods

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies preliminary action by providing a workpiece holder that positions the workpiece before cutting begins. The workpiece holder can be adjusted to present the workpiece at the optimal position, allowing the blade to remain partially retracted while still enabling efficient cutting when engaged. This preliminary positioning reduces the need for full blade exposure and maintains safety while preserving cutting effectiveness

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

Enables quick and easy cutting of elongated members using an existing rotary power tool, allowing for efficient cutting operations without the need for a dedicated cutting tool.

Implementation Method 1

A threaded shaft is received in the housing and coupled to and rotationally driven by the input shaft. A blade holder, holding a cutting blade, is coupled to the threaded shaft. Upon rotation of the input shaft, the threaded shaft rotates, causing the blade holder to move axially forward along the threaded shaft

Methodology Applied
Scientific EffectScrew mechanism: Screw

Data Source

PatentEP4000780A1Power tool accessories for cutting elongated members
Publication Date: 2022.05.25 BLACK & DECKER CORP
  • EP4000780A1 patent drawingFigure 1A
  • EP4000780A1 patent drawingFigure 1B
  • EP4000780A1 patent drawingFigure 2

AI summary

A power tool accessory (10) for cutting elongated members (12) includes a housing (14) having a rear end (16 )and a front end (18), and an input shaft (20) received in the rear end (16) of the housing. The input shaft (20) extends along an axis (X) and is configured to be coupled to a rotary power tool (22), e.g., a corded or cordless drill or an impact driver, to be driven in rotation. A threaded shaft (34) is received in the housing (14) and is coupled to and rotationally driven by the input shaft (20). A slidable blade holder (36), holding a cutting blade (38), is coupled to a front end (40) of the threaded shaft (34). A workpiece holder (52) at the front end portion of the housing (14) is configured to hold an elongated member. Upon rotation of the input shaft (20), the threaded shaft (34) rotates, causing the blade holder (36) to move axially toward the front end portion of the housing (14), causing the blade (38) to move towards the workpiece holder (52) to cut the elongated workpiece.