Electric Knife Blade Holder Oscillation for Acute Angle Cutting
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Solution Overview
Problem
Existing electric knives with axial to-and-fro operating principles are inadequate for cutting operations where the blade is inclined at angles less than 90°, such as cutting cardboard.
Innovation Solution
An electric knife design featuring a blade holder that oscillates transversely around a fixed shaft, driven by a motor with a movement transformation device using an eccentric rod and rolling bearing to impart sinusoidal oscillatory movement, allowing the blade to cut at acute angles between 20° and 70°.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the blade moves parallel to itself in the manner of a saw (axial to-and-fro operating principle), then the structure is simple, but the knife cannot perform cutting operations where the blade is inclined at angles less than 90° relative to the surface to be cut
Solution Approach 1:
The blade holder is designed to perform both rotational movement around a fixed shaft and to-and-fro linear movement, creating a dynamic composite motion that enables cutting at various angles. The fixed shaft provides rotational freedom while the rod mechanism adds linear oscillation, allowing the blade to adapt to different cutting orientations.
Solution Approach 2:
The motion transformation device introduces a second dimension of movement by converting the motor's rotary motion into both rotational movement (around the fixed shaft) and linear to-and-fro movement (via the rod acting on abutments). This dimensional expansion enables the blade to cut at acute angles relative to the surface.
2Productivity
If the blade oscillates transversely around a fixed shaft (sinusoidal oscillatory movement), then cutting performance at acute angles is improved, but the movement transformation device becomes more complex
Solution Approach 1:
The blade holder is made to oscillate sinusoidally in a transverse direction through the action of the rod on the abutments. This mechanical vibration creates the necessary to-and-fro motion for effective cutting at acute angles, transforming the motor's continuous rotation into periodic oscillatory movement that enhances cutting efficiency.
Solution Approach 2:
The rod acts as an intermediary element between the motor shaft and the blade holder. It receives rotary motion from the motor and converts it into sinusoidal oscillatory motion of the blade holder through the abutments, serving as a mechanical mediator that simplifies the overall motion transformation.
3Duration of action of moving object
If the rod acts on transverse abutments via a rolling bearing, then continuous sinusoidal oscillatory movement is achieved, but the device complexity increases
Solution Approach 1:
The rolling bearing enables continuous sinusoidal oscillatory movement by maintaining smooth contact between the rod and abutments throughout the rotation cycle. The bearing ensures uninterrupted motion transmission from the motor shaft through the rod to the blade holder, eliminating dead zones and ensuring continuous cutting action.
Solution Approach 2:
The sliding contact between the rod and abutments is replaced with a rolling contact through the introduction of a rolling bearing. This substitution reduces friction and wear, enabling smoother and more continuous oscillatory motion while simplifying the mechanical interaction between components.
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 efficient cutting at inclined angles by providing a sinusoidal oscillatory movement to the blade, improving cutting performance on surfaces like cardboard while preventing longitudinal movement of the blade holder, and incorporating a rechargeable battery with a safety switch for motor control.
Implementation Method 1
a rod connected to an output shaft of the motor, eccentric relative to and parallel to the output shaft and adapted to cause the blade holder to oscillate around the fixed shaft
Implementation Method 2
The rod advantageously acts on the transverse abutments of the blade holder via a rolling bearing centered on the rod
Implementation Method 3
the blade holder is moved in rotation and to-and-fro relative to said fixed shaft by said motor and imparts an oscillatory movement to the blade
Data Source
AI summary
An electric knife including a knife body, forming a handle housing an electric motor, and a blade holder, received in the handle, carrying a blade and maneuvered by the motor via a device for transforming rotary movement of the motor into alternating movement of the blade holder. The knife body includes a fixed shaft perpendicular to the blade on which the blade holder is mounted and which is positioned so that the blade holder is moved in rotation and to-and-fro relative to the fixed shaft by the motor to impart an oscillatory movement to the blade.