Portable Rebar Bender With Selectable Bend Radius Control

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Solution Overview

Problem

Existing rebar bending tools lack the flexibility to accommodate different diameters and bend radii, as they are not designed to handle various specifications of rebar efficiently, which can lead to compromised bending quality and safety due to fixed curvature limits.

Innovation Solution

A portable electric power tool with a bend mechanism featuring a bias portion and abutment portions that allow for adjustable bending radii, utilizing a DC brushless motor and planetary gear arrangement to provide controlled bending forces, enabling users to bend rebar of different diameters to specific angles and radii.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a fixed curvature bending tool is used, then the tool structure is simple, but it cannot accommodate different rebar diameters and bend radii requirements

Engineering Contradiction:
Improveability to handle different rebar diameters and bend radiiVSAvoidbend mechanism structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The bend mechanism incorporates a movable bias portion that can be adjusted to different positions along the longitudinal axis of the tool. This dynamic adjustment capability allows the tool to accommodate various rebar diameters and bend radii requirements, transforming a static fixed-curvature tool into an adaptable system that responds to different construction needs.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The bend mechanism is divided into distinct functional portions: a support portion with fixed abutment portions and a movable bias portion with an adjustable abutment portion. This segmentation allows independent adjustment of the bias portion relative to the support portion, enabling precise control over bending radius while maintaining overall structural integrity.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If manual rebar bending is performed, then no special tool is needed, but bending precision and safety are compromised

Engineering Contradiction:
Improvebending angle and radius precisionVSAvoidportable electric power tool
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces manual mechanical bending operations with an electrically powered bend mechanism. A DC brushless motor drives a planetary gear arrangement that converts rotational motion into linear movement of the bias portion, providing controlled, repeatable bending forces that ensure precise bending angles and radii while reducing physical strain on operators.

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

Solution Approach 2:

The bend mechanism is designed as a self-contained portable unit with an integrated battery pack that provides electrical power. The tool performs its own bending operation without requiring external power sources or additional equipment, making it a complete self-service solution for precision rebar bending in construction settings.

Inventive Principle:
Principle #25Self-service

3Force

If high bending force is applied to thick rebar, then bending can be achieved, but the rebar may be damaged if bent beyond acceptable curvature limits

Engineering Contradiction:
Improvebending forceVSAvoidrebar integrity
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The adjustable bias portion allows operators to set the desired bending radius before applying force. By pre-positioning the abutment portion at the appropriate distance from the rebar, the system provides geometric feedback that limits the maximum curvature achievable, ensuring that even high bending forces do not exceed acceptable curvature limits and compromise rebar integrity.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system allows dynamic adjustment of the bending radius parameter by repositioning the bias portion along the longitudinal axis. This parameter change capability enables operators to select appropriate bend radii based on rebar diameter and required application, ensuring that bending forces are applied within safe limits while still achieving the necessary bend for each specific rebar specification.

Inventive Principle:
Principle #35Parameter changes

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 allows for precise and safe bending of rebar by varying the bending radius, accommodating different rebar diameters and angles, enhancing user control and safety by ensuring the rebar is bent within acceptable curvature limits, thus improving construction efficiency.

Implementation Method 1

DC brushless motor

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

planetary gear arrangement

Methodology Applied
Scientific EffectMechanical advantage: Mechanical Advantage

Data Source

PatentEP4458486A1Portable electric power tool for bending elongate objects
Publication Date: 2024.11.06 BLACK & DECKER CORP
  • EP4458486A1 patent drawingFigure 1A
  • EP4458486A1 patent drawingFigure 1~2
  • EP4458486A1 patent drawingFigure 3~5

AI summary

A portable electric power tool for bending elongate objects comprising an electric motor having a motor output shaft, a bend mechanism having a support portion and a bias portion wherein first and second abutment portions of the support portion are separated by a space between them through which a third abutment portion provided by the bias portion can be moved in use and wherein the bend mechanism is operatively coupled to the motor output shaft via a transmission of the tool which in use causes linear relative movement between the bias portion and the support portion for causing force to be applied by the first, second and third abutment portions to an elongate object in use at different locations along the length of the elongate object for bending the elongate object, the third abutment portion having a plurality of bending surface portions each of which has a different radius of curvature and wherein the third abutment portion can be secured in different rotational positions thereby enabling a user to select the bending surface portion which engages the elongate object being bent in use.