Electric Hair Trimmer Speed Control Through Partial Trigger Input

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Solution Overview

Problem

Conventional electric hair cutting devices have limited motor speed adjustment capabilities, leading to inefficiencies in cutting various hair types and user preferences, increased heat, vibration, noise, and faster battery drain, and require manual speed changes that can cause inaccuracies.

Innovation Solution

A hair trimmer with a trigger that allows for continuous variable speed control through partial actuation, a control module that adjusts motor speed based on trigger input, and a digital display for setting and monitoring speed limits, enhancing user control and ergonomic design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple discrete speed settings are provided, then motor speed adaptability is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:

Improvemotor speed adaptabilityVSAvoiddevice complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements continuous variable speed control through a trigger mechanism that allows the user to dynamically adjust motor speed across a continuous range rather than selecting from discrete predetermined settings. The control module receives analog input from the trigger position and continuously adjusts the motor speed accordingly, making the system adaptive without requiring multiple fixed speed switches or complex selection mechanisms.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the control parameter from discrete stepped values to continuous analog input through the trigger. The trigger's position along its travel range corresponds to different motor speeds, allowing smooth parameter adjustment. This approach provides full speed adaptability while keeping the control mechanism simple and intuitive.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If motor speed is increased for thick or coarse hair, then cutting efficiency is improved, but heat generation, vibration, and battery consumption increase

Engineering Contradiction:

Improvecutting efficiencyVSAvoidheat generation and vibration

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The system allows dynamic adjustment of motor speed based on real-time user needs and hair conditions. Instead of operating at a fixed high speed that always generates excessive heat and vibration, the motor speed adapts to the specific cutting requirements. The user can increase speed temporarily when encountering thick hair sections and reduce it for finer work, minimizing harmful effects while maintaining cutting efficiency when needed.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The trigger-based control enables periodic or intermittent high-speed operation rather than continuous high-speed running. The user activates high speed only when encountering resistant hair sections and returns to lower speeds for normal cutting, reducing cumulative heat generation and vibration while maintaining overall cutting efficiency.

Inventive Principle:

Principle #19Periodic action

3Ease of manufacture

If discrete speed settings are used, then manufacturing cost is reduced, but user control precision and continuity are insufficient

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoiduser control precision

Core Design Contradiction:

Ease of manufactureVSEase of operation

Solution Approach 1:

The patent replaces complex mechanical speed selection mechanisms (multiple switches, dials, or gears) with a simple electronic control system that reads the trigger position and adjusts motor speed accordingly. This substitution maintains manufacturing simplicity while dramatically improving user control precision, as the electronic system can provide continuous fine-grained adjustment without the mechanical complexity of multiple discrete selection mechanisms.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Device complexity

If manual speed changes are required during cutting, then device complexity is reduced, but cutting accuracy and continuity are compromised

Engineering Contradiction:

Improvecontrol mechanism simplicityVSAvoidcutting accuracy

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The trigger-based continuous speed control allows the user to adjust motor speed without stopping the cutting action. The control module responds in real-time to trigger position changes, maintaining continuous blade movement and cutting flow. This eliminates the need to halt cutting to change speed settings, preserving cutting accuracy and preventing visible blending lines or inaccuracies in the haircut.

Inventive Principle:

Principle #20Continuity of useful action

Data Source

PatentUS20250332750A1Electric hair cutting device having user input dependent speed control

Publication Date: 2025.10.30 WAHL CLIPPER CORP

AI summary

An electric hair cutting device including a housing having a first end and a second end opposite the first end, a bladeset mounted to the housing at the first end, the bladeset having a stationary blade and a reciprocating blade, an electric motor electrically connected to a power source within the housing, a drive shaft operatively connecting the electric motor to the reciprocating blade, a control module within the housing which controls a rotational speed of the electric motor; and a trigger which sends an actuation signal to the control module based on a partial actuation of the trigger between a minimum actuation and a maximum actuation, the control module adjusting a rotational speed of the electric motor based on the actuation signal.