Concentric Dual-Spindle Mixer Output for Wide Speed Torque Range
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Solution Overview
Problem
Handheld electric mixers with universal motors often have a narrow speed torque range, limiting their versatility as they struggle to achieve both low speeds for delicate food preparation and high speeds for thorough mixing, due to poor voltage speed control.
Innovation Solution
A handheld electric mixer with dual concentric rotational output spindles, where the second spindle turns at a slower speed, one-third that of the first, driven by a single motor via a gear system, allowing different tools to engage with either spindle, thus varying the speed based on the tool inserted without changing the motor speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a single motor with voltage speed control is used, then the mixer can achieve high mixing speeds, but the speed torque range is narrow and voltage speed control is poor at low speeds
Solution Approach 1:
The patent divides the single output shaft into two concentric spindles (first spindle and second spindle) that rotate at different speeds. The first spindle is directly driven by the motor at high speed, while the second spindle is driven through a gear reduction mechanism at low speed. This segmentation allows the mixer to handle both high-speed mixing and low-speed delicate preparation tasks effectively.
2Adaptability or versatility
If dual speed output is implemented, then versatility is improved, but device complexity increases
Solution Approach 1:
The patent employs a nested gear system where a first gear is positioned on the first spindle and a second gear is positioned on the second spindle, with the second gear being concentric to and larger than the first gear. This nested arrangement allows compact packaging of the dual-speed mechanism within the mixer housing, minimizing space requirements while maintaining the complexity of achieving dual speeds.
3Volume of moving object
If concentric spindles are used, then space efficiency is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent utilizes asymmetric gear sizing where the second gear is explicitly designed to be larger in diameter than the first gear. This asymmetry, combined with the concentric arrangement, creates distinct rotational paths for each spindle while maintaining compact space utilization. The asymmetric design helps in achieving the desired speed reduction ratio while managing the manufacturing precision challenges of concentric alignment.
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 the mixer to operate at multiple speeds depending on the tool inserted, enhancing versatility by allowing both high-speed mixing and low-speed preparation without the need for complex speed control mechanisms, improving the mixer's ability to handle various food items effectively.
Implementation Method 1
The first rotational output spindle has a gear driven directly from an output of the motor. The appliance includes a stub-shaft located parallel to the first and second spindles. The stub-shaft is driven from the first spindle by a first pair of gears, and the stub shaft drives the second spindle via a second pair of gears.
Data Source
AI summary
An electric appliance has first and second rotational output spindles located within a housing. The first and second spindles have respective first and second couplings for attachment of first and second work tools to the first and second spindles, respectively. The second rotational output spindle is concentric with the first rotational output spindle such that connection of one of the first and second work tools to the corresponding spindle excludes connection of the other of the first and second work tools to the corresponding spindle. The first rotational output spindle has a first rotational speed that is different from a second rotational speed of the second output spindle.