Trimmer Head Automatic Line Feed Mechanism
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Solution Overview
Problem
Existing trimmer heads with automatic feed mechanisms face issues such as tangling, wedging, clamping, and welding of trimmer lines, which can lead to impaired function and require disassembly for maintenance, and they often result in unwanted circular marks and increased cutting height due to the need to push the trimmer head against the ground for line feeding.
Innovation Solution
A trimmer head design featuring an automatic feed mechanism that releases trimmer line when subjected to a higher rate of change in rotational speed, combined with a manual actuator for line release, allowing for simple and quick feeding without disassembly, reducing the risk of tangling and maintaining a low cutting height.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a push button is arranged on the underside of the trimmer head to enable manual line feeding, then the user can feed more line by pushing the trimmer head to the ground, but this arrangement increases the cutting height and causes unwanted circular marks in the vegetation
Solution Approach 1:
The patent removes the push button from the trimmer head housing and relocates the line feeding function to a spool cap with a release mechanism. Users can feed line by manipulating the spool cap without touching the ground, eliminating circular marks while maintaining ease of operation
Solution Approach 2:
The patent introduces a spool cap as an intermediary component between the user and the line feeding mechanism. The spool cap includes a release mechanism that allows line to be fed without pushing the trimmer head against the ground, thus preventing harmful circular marks in the vegetation
2Ease of operation
If the trimmer head is pushed to the ground to activate the push button for line feeding, then the line can be fed, but this increases the cutting height
Solution Approach 1:
The patent extracts the line feeding activation mechanism from the bottom of the trimmer head and integrates it into the spool cap. This allows users to feed line by operating the spool cap without pushing the trimmer head to the ground, thereby maintaining a low cutting height suitable for precise trimming
3Ease of operation
If an automatic feed mechanism is implemented to release trimmer line during operation, then the need to push the trimmer head to the ground is eliminated, but issues such as tangling, wedging, clamping, and welding of the trimmer line occur
Solution Approach 1:
The patent pre-arranges the trimmer line in grooves on the spool and designs the spool cap with a controlled release mechanism. When the release mechanism is activated, the line is fed in a controlled manner rather than being suddenly released, preventing tangling, wedging, clamping, and welding issues
Solution Approach 2:
The spool cap acts as an intermediary that controls the release of the trimmer line. It includes a release mechanism that regulates line feeding, preventing the line from being suddenly released and causing tangling or wedging, while still enabling automatic feeding during operation
4Productivity
If the trimmer line is spooled loosely around the spool to allow automatic feeding, then the line can be fed during operation, but the line may become tangled, wedged, or clamped due to centrifugal forces and resistance in vegetation
Solution Approach 1:
The patent designs grooves on the spool surface that guide the trimmer line in specific paths. These grooves ensure the line is spooled in a controlled manner, preventing tangling and wedging while still allowing automatic feeding during operation by maintaining proper line tension and alignment
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
The solution enables user-friendly, efficient, and reliable trimmer line feeding during operation and standstill, preventing tangling and maintaining a low cutting height, thus overcoming the drawbacks of prior art solutions.
Implementation Method 1
the trimmer line is subjected to centrifugal forces and meets resistance in vegetation when cutting
Data Source
AI summary
A trimmer head (1) is disclosed arranged to be driven around a rotational axis (ax), via an interface (2), to rotate a trimmer line (3). The trimmer head (1) comprises a housing (1a, 1b), the interface (2), a trimmer line spool (5, 5′), and an automatic feed mechanism (7). The automatic feed mechanism (7) is configured to release a trimmer line (3) spooled around the trimmer line spool (5, 5′) when the trimmer head (1) is subjected to a change in rotational speed, via the interface (2), at a higher rate than a threshold rate of change in rotational speed. The trimmer head (1) further comprises an actuator (9, 9′) connected to the automatic feed mechanism (7) such that a manual actuation of the actuator (9, 9′) releases the trimmer line (3) spooled around the trimmer line spool (5, 5′). The present disclosure further relates to a trimmer (13) comprising a trimmer head (1).