Trimming Head Sliding Lock Mechanism for Noise Reduction

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Solution Overview

Problem

Existing electric hair and beard trimmers with removable cutting heads suffer from bulkiness, noise due to relative movement, and increased production costs, along with complex user interaction and inefficient hair evacuation.

Innovation Solution

A hair or beard trimmer design featuring a cutting head with a sliding attachment mechanism using compression means like a metallic leaf spring for secure locking, reducing the attachment area and eliminating flexible hooks, combined with a pin-driven oscillatory movement and adjustable combs for improved maneuverability and hair evacuation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If hooks made of flexible material are used to attach the cutting head to the casing, then the cutting head can be easily attached and detached, but the flexible hooks accentuate the displacement of the cutting head with respect to the casing and favor collisions between parts, which increases noise during operation

Engineering Contradiction:
Improveease of attachmentVSAvoidnoise
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent removes the flexible hooks from the attachment mechanism and replaces them with a rigid tongue-groove system. The cutting head is attached by sliding the tongue into the groove, eliminating the need for flexible elements that cause displacement and noise during operation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using flexible hooks that allow movement, the patent employs a rigid sliding fit where the tongue of the cutting head fits into a groove on the casing. This inverts the approach from flexible connection to rigid connection, preventing displacement and collisions.

Inventive Principle:
Principle #13The other way round (Inversion)

2Reliability

If hooks and spring blades are used for fixing the cutting head, then the cutting head can be securely held, but the triangular section of the fixing zone increases the bulk of the device

Engineering Contradiction:
Improveholding strengthVSAvoidbulk
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent extracts the spring blades and triangular fixing zone from the design, replacing them with a simple sliding tongue-groove mechanism. This reduces the volume of the fixing zone while maintaining secure attachment through the interlocking geometry of the tongue and groove.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If an unlocking device with a lever is added to release the cutting head, then the cutting head can be securely locked in place, but additional parts increase the cost of production and complicate the use of the product

Engineering Contradiction:
Improvelocking strengthVSAvoidcomplexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs a self-locking sliding mechanism where the tongue fits into the groove and automatically locks in place through friction and geometric interlocking. No separate unlocking device or lever is needed; the user simply pushes the cutting head to attach it, and it remains secured during operation.

Inventive Principle:
Principle #25Self-service

4Adaptability or versatility

If the cutting head is made removable for hygiene and accessibility, then cleaning and head replacement become possible, but the attachment mechanism increases the area of the attachment zone and makes the device more cumbersome

Engineering Contradiction:
ImproveremovabilityVSAvoidattachment area
Core Design Contradiction:
Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The patent removes the complex multi-point attachment mechanisms and replaces them with a single sliding tongue-groove interface. This maintains the removability of the cutting head for hygiene and replacement while minimizing the attachment zone area to a simple linear groove.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP2676777B1Electric mower with novel attachment of a cutting head
Publication Date: 2015.12.30 SEB SA
  • EP2676777B1 patent drawingFigure 1
  • EP2676777B1 patent drawingFigure 2
  • EP2676777B1 patent drawingFigure 3

AI summary

The trimmer has a longitudinal gripping case, and an electrical motor is contained in the case. A U-shaped base (31) comprises a set of hooks (37, 38), and a blade (32) is fixed at the base. Another blade (33) is intended to move linearly back and forth with regard to the former blade. A guidance unit (34) is arranged interdependent of the latter blade, and is intended to receive an actuation unit i.e. pin. A compression unit (8) or metal blade is arranged at a locking end (EV) opposed to a cut end (EC) so as to maintain a head on the case by clippings.