String Trimmer Fan Clutch for Switching Between Cutting and Blowing
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Solution Overview
Problem
Users of string trimmers face the inconvenience of needing a separate tool, such as a broom or blower, to clean up debris after cutting grass, which adds expense and hassle.
Innovation Solution
A string trimmer with a built-in blower feature, utilizing a one-way pinion gear mechanism that allows the tool to selectively engage the cutting head for trimming or disengage it for blowing, using a motor-driven fan to generate airflow without rotating the cutting line spool.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a string trimmer is used to cut grass, then the cutting function is achieved, but the cut grass leaves a messy appearance requiring a separate blower tool
Solution Approach 1:
The patent combines the string trimmer cutting function and the blower debris removal function into a single integrated device. The motor drives both the spool housing for cutting line rotation and the fan for air generation, allowing users to perform both cutting and blowing operations with one tool, thereby eliminating the need for separate tools and reducing overall device complexity despite the integration of multiple functions.
Solution Approach 2:
The string trimmer is designed with multi-functionality by incorporating both cutting and blowing capabilities. The single device can switch between cutting mode (spool housing rotates) and blowing mode (fan operates), making it a universal tool that replaces multiple specialized tools and improves operational convenience.
2Adaptability or versatility
If the motor rotates in both directions to provide cutting and blowing functions, then versatility is improved, but the mechanism complexity increases
Solution Approach 1:
The patent introduces a one-way pinion gear as an intermediary mechanism between the motor and the spool housing. This intermediary component automatically controls the power transmission based on motor rotation direction: it engages to transmit power to the spool housing when the motor rotates in the cutting direction, and disengages when the motor rotates in the blowing direction. This simple mechanical intermediary achieves versatile functionality without requiring complex control systems or multiple transmission paths.
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 and convenient debris removal without the need for additional tools, enhancing user experience by integrating cutting and blowing functions into a single device.
Implementation Method 1
The motor rotates in a second direction, opposite to the first. The fan, which is directly connected to the motor, rotates to generate the airflow.
Implementation Method 2
The fan, which is directly connected to the motor, rotates to generate the airflow.
Data Source
Figure 1
Figure 1A
Figure 2
AI summary
The present invention is directed to a string trimmer having a blower feature incorporated therein. The string trimmer has a cutting head for holding a spool with cutting line. The cutting line is rotated at high speed to cut grass and other vegetation. The cutting head also includes a fan for generating an airflow to act as a blower. The string trimmer can be operated in two modes. In a first mode, both the fan and the spool housing are engaged with the motor so that the rotation of the spool housing performs a cutting operation. In a second mode, the motor engages only the fan to blow air, and the spool housing is disengaged so no cutting operation is performed.