Trimmer Head Clamping Device U-Bracket Reliability
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Solution Overview
Problem
The existing line mowing heads for brush cutters have complex structures that are prone to failure, particularly in the pivot bearing of the clamping device, leading to insecure clamping of the cutting line over a long service life.
Innovation Solution
A line mowing head with a clamping device featuring a U-shaped bracket that integrates the clamping body, clamping spring, and pivot bolt as a single component, allowing for preassembly as a modular unit and simple assembly, with the clamping spring loading the clamping body against a stop to ensure secure clamping and absorb all clamping forces, thus preventing failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a complex clamping device structure with separate pivot bearing in the main body is used, then the clamping function can be achieved, but the device is prone to failure over long service life
Solution Approach 1:
The patent integrates the pivot bearing directly into the U-shaped bracket structure, merging the clamping body, pivot bearing, and spring assembly into a single integrated component. This eliminates separate pivot bearings in the main body, reducing the number of parts and potential failure points while maintaining clamping functionality.
Solution Approach 2:
The clamping device is segmented into a modular U-shaped bracket assembly that can be pre-assembled and tested independently before installation in the main body. This segmentation allows for easier manufacturing, quality control, and replacement if failure occurs, improving overall reliability.
2Device complexity
If a simple clamping device structure is used, then the device complexity is reduced, but secure clamping of the cutting line over long service life cannot be ensured
Solution Approach 1:
The U-shaped bracket integrates multiple functions (clamping body, pivot bearing, spring mounting) into a single robust structure, achieving simplicity without sacrificing reliability. The integrated design ensures all clamping forces are properly absorbed and distributed within the bracket structure.
Solution Approach 2:
The U-shaped bracket appears to be constructed from a robust material capable of withstanding repeated clamping cycles and centrifugal forces. The integration of metal components with the plastic base body creates a composite structure that combines the strength of metal with the ease of molding plastic parts.
3Reliability
If the pivot bearing is located in the main body of the line mowing head, then the clamping function can be achieved, but the pivot bearing is susceptible to failure
Solution Approach 1:
The pivot bearing function is segmented from the main body and integrated into the U-shaped bracket assembly. This allows the bracket to be pre-assembled with its bearing and spring mechanism, then installed as a single unit into the main body, simplifying the overall assembly process while improving bearing reliability.
Solution Approach 2:
The U-shaped bracket acts as an intermediary component that houses the pivot bearing and spring assembly, mediating between the main body and the clamping body. This intermediary structure protects the bearing from direct exposure to debris and operational stresses in the main body environment.
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 provides reliable and secure clamping of the cutting line over a long period, minimizing the risk of clamping device failure and ensuring consistent operation by distributing clamping forces effectively within the U-shaped bracket.
Implementation Method 1
The clamping body is spring-loaded into its clamping position by a clamping spring
Implementation Method 2
The centrifugal force acting on the thread and the clamping body increasing the clamping effect by the clamping body
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a trimmer head (1) for a brushcutter, comprising an elongated cutting line (5) clamped in a base body (2) of the trimmer head (1), which projects outwards through a line opening (3) of the base body (2) and defines a cutting plane (12) when the trimmer head (1) rotates. A clamping device (8) for the cutting line (5) is arranged in the base body (2) of the trimmer head (1), comprising a clamping body (10) movable about a pivoting bolt (16), the pivoting axis (26) of the pivoting bolt (16) lying in a plane (13) approximately parallel to the cutting plane (12). The clamping body (10) is spring-loaded by a clamping spring (25) into a clamping position in which the cutting line (5) is held between a clamping surface (28) and the clamping body (10). The clamping surface (28) and the bearing of the pivot bolt (16) are formed on a common component.To obtain a robust, easy-to-assemble clamping device, the component (17) is designed as a U-shaped bracket (19), and the clamping body (10) is positioned between the legs (21, 22) of the bracket (19). The pivot pin (16) of the clamping body (10) is mounted in the leg ends of the bracket (19), with the clamping surface (28) for the cutting thread being formed on the web (20) of the U-shaped bracket (19) connecting the legs (21, 22).