Dual Motor Drive for Bread Slicer Blade Speed Control

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Solution Overview

Problem

Existing motor drives for circular blades in bread slicers lack the ability to variably adjust the rotational speed of the blade to cutting speed, leading to inefficient cutting of soft or warm bread, which often results in torn slices.

Innovation Solution

A motor drive system utilizing two separate drive motors, where one motor drives the eccentric arm and the other drives the circular blade independently, allowing for adjustable speed ratios and a compact design through the use of a hollow and solid shaft configuration with toothed belts for efficient power transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a planetary gear system with a single drive motor is used, then the device complexity is reduced and cost is lowered, but the ability to independently control blade rotational speed and cutting speed is lost, resulting in poor cutting quality for soft or warm bread

Engineering Contradiction:
Improvedrive system complexityVSAvoidspeed ratio adjustment capability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The drive system is segmented into two independent drive motors: a first drive motor that controls the eccentric arm movement (and thus the cutting speed), and a second drive motor that controls the circular blade rotation (and thus the blade speed). This segmentation allows independent control of cutting speed and blade speed, enabling adaptation to different bread types while maintaining manageable system complexity through modular design.

Inventive Principle:
Principle #1Segmentation

2Productivity

If the rotational speed of the circular blade is increased to提高 cutting speed, then productivity increases, but soft bread slices tear during cutting

Engineering Contradiction:
Improvecutting speedVSAvoidslice tearing
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system dynamically adjusts the ratio between blade rotational speed and cutting speed based on the bread type being processed. For soft or warm bread, the control unit reduces the blade rotational speed relative to the cutting speed, preventing slice tearing. For harder breads, the blade speed can be increased to maintain productivity. This dynamic adjustment capability resolves the contradiction between cutting speed and slice integrity.

Inventive Principle:
Principle #15Dynamics

3Object-affected harmful factors

If the rotational speed of the circular blade is decreased to cut soft bread gently, then slice quality improves, but the cutting process becomes slower

Engineering Contradiction:
Improveslice tearingVSAvoidcutting speed
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The control unit enables dynamic adjustment of the blade rotational speed to match the cutting speed. When processing soft bread, the system可以降低 blade speed relative to cutting speed to prevent tearing. When processing harder breads or when higher productivity is needed, the blade speed can be increased. This dynamic capability allows the system to optimize both slice quality and cutting speed depending on the specific application.

Inventive Principle:
Principle #15Dynamics

4Adaptability or versatility

If two separate drive motors are used to independently control blade speed and cutting speed, then adaptability and cutting quality improve, but device complexity and cost increase

Engineering Contradiction:
Improvespeed ratio adjustment capabilityVSAvoiddrive system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The hollow shaft of the first drive motor is designed to accommodate the solid shaft of the second drive motor, creating a nested configuration. This nesting allows both drive motors to be compactly integrated within the housing space, reducing the overall footprint and making the increased complexity of having two motors more manageable. The nested design enables independent control of blade speed and cutting speed while maintaining a relatively compact structure.

Inventive Principle:
Principle #7Nested doll (Nesting)

5Volume of moving object

If a hollow shaft configuration with nested shafts is used to accommodate two drive motors, then the device becomes more compact, but manufacturing complexity increases

Engineering Contradiction:
Improvedrive system volumeVSAvoidshaft manufacturing complexity
Core Design Contradiction:
Volume of moving objectVSEase of manufacture

Solution Approach 1:

The hollow shaft of the first drive motor is designed to accommodate the solid shaft of the second drive motor, creating a nested configuration that maximizes space utilization. This nested design allows both drive motors to be compactly integrated within the housing space, reducing the overall footprint. While the manufacturing of nested shafts requires precision, the modular design allows for standardized production and assembly, making the complexity manageable.

Inventive Principle:
Principle #7Nested doll (Nesting)

Data Source

PatentEP3603908B1Motor drive for a cutting machine
Publication Date: 2021.11.24 SILLER HOLDING GMBH
  • EP3603908B1 patent drawingFigure 1

AI summary

The invention relates to a motor drive (10) for a cutting machine. The motor drive (10) comprises a first drive motor (12) and a second drive motor (14). The first drive motor (12) rotates an eccentric arm (22). The circular blade (32) of the cutting machine is rotatably mounted on the eccentric arm (22) and is rotated by the second drive motor (14).