Electric Rebar Bender With Hall-Sensed Position Control
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Solution Overview
Problem
Hydraulic rebar bending tools are heavy, require high maintenance, and rely on multiple sensors that increase the risk of tool failure due to sensor failure.
Innovation Solution
A portable electric power tool with a DC brushless motor, planetary gear arrangement, and a bias portion mechanism for bending rebar, utilizing a Hall sensor and controller to accurately control the bending process without needing multiple sensors, improving weight distribution and reducing maintenance needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If hydraulic rebar bending tools are used, then bending force is sufficient, but the tool becomes heavy and requires high maintenance
Solution Approach 1:
The patent replaces the hydraulic system with an electric motor system. Specifically, an electric motor (114) drives a ball screw mechanism (58) that converts rotational motion into linear motion of the threaded rod (62), which directly actuates the bend mechanism (20). This substitution eliminates the need for hydraulic fluid, pumps, and associated components, significantly reducing tool weight while maintaining sufficient bending force through direct mechanical drive.
Solution Approach 2:
The patent divides the bending force generation into modular components: the electric motor (114) provides rotational power, the planetary gear arrangement (50) multiplies torque, and the ball screw mechanism (58) converts rotation to linear motion. This segmentation allows each component to be optimized independently and facilitates easier maintenance compared to integrated hydraulic systems.
2Measurement precision
If multiple sensors are used to monitor internal component position, then positioning accuracy is improved, but the risk of tool failure increases due to sensor failure
Solution Approach 1:
The patent replaces multiple electronic position sensors with a single Hall sensor (45) that monitors the position of the bias portion (24) by detecting the position of a magnet (105). This single-sensor approach maintains adequate positioning control while eliminating the failure risks associated with multiple sensors. The Hall sensor provides reliable position feedback through magnetic field detection without the complexity of multiple sensing elements.
Solution Approach 2:
The controller (44) uses motor status information (such as current, voltage, and back-EMF) to determine the position of the bias portion (24) without relying solely on external sensors. This self-sensing capability allows the system to monitor component position using information already available from the motor control system, reducing dependency on additional sensors and improving overall system reliability.
3Force
If hydraulic components are used, then bending capability is achieved, but maintenance requirements increase
Solution Approach 1:
The patent replaces hydraulic components (pumps, valves, fluid lines) with electric motor and mechanical transmission components. The electric motor (114) and planetary gear arrangement (50) are sealed units with minimal maintenance requirements, and the ball screw mechanism (58) has no fluid seals or hoses that can leak. This substitution dramatically reduces maintenance needs while preserving full bending capability through direct mechanical actuation.
Solution Approach 2:
The patent extracts and eliminates the hydraulic subsystem entirely, removing pumps, reservoirs, filters, and fluid management components. By taking out the hydraulic system and replacing it with an electric drive system, the patent eliminates the maintenance activities associated with hydraulic fluid changes, seal replacements, and contamination management, while maintaining the essential bending function.
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 provides efficient, precise, and reliable bending of rebar with improved weight distribution and reduced risk of failure, enhancing user convenience and tool longevity.
Implementation Method 1
A portable electric power tool with a DC brushless motor, planetary gear arrangement, and a bias portion mechanism for bending rebar, utilizing a Hall sensor and controller to accurately control the bending process
Implementation Method 2
A portable electric power tool with a DC brushless motor
Implementation Method 3
planetary gear arrangement
Data Source
AI summary
A portable electric power tool for bending elongate objects includes an electric motor, a bender having a body portion and a bending portion which is axially moveable relative to the body portion. The bender is operatively coupled to the electric motor for causing the axial movement between a home position and a retracted position for causing force to be applied by the bender at different locations along the length of the elongate object for bending the elongate object; a home position sensor for generating output indicative that the bending portion has reached the home position during a reset stage of operation and a controller for receiving motor turn information indicative of the number of turns of the electric motor and for monitoring the axial position of the bending portion based on the motor turn information and the output generated by the home position sensor.