Integrated Trimmer Head Spool Layout for Compact Motor Packaging

Solution Overview

Problem

Existing trimmers often have a bulky form factor due to the separation of the motor and trimmer head, which is not compact and efficient.

Innovation Solution

An integrated motor and trimmer head assembly where the motor is housed within the spool of the trimmer head, reducing the overall size and form factor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the motor is separated from the trimmer head and housed in a motor housing proximate the grip, then the motor can be independently positioned for ease of assembly, but the overall form factor becomes bulky and non-compact

Engineering Contradiction:

Improveease of assemblyVSAvoidform factor

Core Design Contradiction:

Ease of manufactureVSVolume of moving object

Solution Approach 1:

The motor is integrated directly into the trimmer head assembly, merging previously separate components (motor housing and trimmer head) into a single unified structure. This eliminates the need for separate motor housing and drive shaft connections, thereby reducing the overall form factor while maintaining ease of assembly through the integrated design

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The motor is positioned within the cavity of the spool, nesting one component inside another. The spool includes a cavity that receives and houses the motor, allowing the motor to be compactly integrated within the existing trimmer head structure without increasing the overall volume

Inventive Principle:

Principle #7Nested doll (Nesting)

2Ease of manufacture

If the motor is positioned directly outside the trimmer head connected with a drive shaft, then the motor can be independently positioned, but the overall form factor becomes bulky

Engineering Contradiction:

Improveindependent positioningVSAvoidform factor

Core Design Contradiction:

Ease of manufactureVSVolume of moving object

Solution Approach 1:

The motor is integrated directly into the trimmer head assembly, merging previously separate components (motor housing and trimmer head) into a single unified structure. This eliminates the need for separate motor housing and drive shaft connections, thereby reducing the overall form factor while maintaining ease of assembly through the integrated design

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The motor is positioned within the cavity of the spool, nesting one component inside another. The spool includes a cavity that receives and houses the motor, allowing the motor to be compactly integrated within the existing trimmer head structure without increasing the overall volume

Inventive Principle:

Principle #7Nested doll (Nesting)

Data Source

PatentUS20260026431A1Trimmer head assembly having an integrated motor

Publication Date: 2026.01.29 MILWAUKEE ELECTRIC TOOL CORP

AI summary

Trimmer head assemblies and trimmers are provided. A trimmer head assembly includes a trimmer head that has a housing and a spool positioned within the housing. The spool includes a first flange portion, a second flange portion, and a body portion extending between the first flange portion and the second flange portion. The spool defines a cavity extending through the first flange portion, the second flange portion, and the body portion. The trimmer head assembly further includes a motor positioned in the cavity.