Anti-Vibration Coil Spring Centering for Hand-Held Power Tools
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Solution Overview
Problem
Hand-held implements, such as chainsaws, face challenges in maintaining effective vibration decoupling and guidance properties under high loads, often leading to undesirable lateral movement and overloading due to forces perpendicular to the coil spring's longitudinal axis, which existing anti-vibration systems fail to adequately address.
Innovation Solution
The implementation of centering elements on the end faces of holding elements, which are angled to align obliquely with the loading direction, prevents forces perpendicular to the coil spring's axis, thereby limiting relative movement between the motor and handle units, using cone and recess designs to center the holding elements and prevent unnecessary stress on the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the end faces of the holding elements are aligned obliquely to the direction of load to act as stop buffers, then the number of additional stop components is reduced, but lateral forces perpendicular to the coil spring axis are generated causing undesirable relative movement and overloading
Solution Approach 1:
The holding elements are segmented into functional zones: the main body provides stop buffering function, while separate centering elements (protrusions and corresponding recesses) provide lateral alignment. This segmentation allows each element to perform its specific function without interfering with the other, resolving the contradiction between simplified structure and reliable guidance.
Solution Approach 2:
The centering elements act as intermediary features between the holding elements that prevent direct lateral contact and force transmission. By introducing these intermediate alignment features, the system achieves proper guidance without requiring complex additional components, maintaining structural simplicity while improving reliability.
2Reliability
If stop buffers are added to limit relative movement between motor unit and handle unit, then guidance properties improve, but device complexity increases
Solution Approach 1:
The stop buffering function and centering function are merged into a single integrated solution: the holding elements themselves serve as stop buffers, while their centering elements provide lateral alignment. This merging eliminates the need for separate stop components, achieving improved guidance properties without increasing device complexity.
Solution Approach 2:
The holding elements are designed with multi-functionality: they simultaneously provide mechanical retention of the coil spring, act as stop buffers against excessive compression, and through their centering elements provide lateral alignment. This multi-functionality reduces the total component count while maintaining reliable guidance properties.
3Strength
If the coil spring is fully enclosed by holding elements, then structural integrity improves, but installation space increases and vibration isolation performance decreases
Solution Approach 1:
The holding elements provide structural support and retention only where needed: at the ends of the coil spring where the retaining elements are screwed in. The middle section of the coil spring remains exposed and uncovered, maintaining structural integrity at critical locations while minimizing overall volume and allowing vibration isolation.
4Strength
If the retaining elements extend radially outside the coil spring for better retention, then holding strength improves, but the outer circumference is blocked reducing vibration isolation effectiveness
Solution Approach 1:
The retaining elements extend radially only at their mounting locations to provide secure retention of the coil spring ends. They do not extend along the entire length of the coil spring, leaving the outer circumference exposed where vibration isolation is needed. This localized extension approach satisfies both retention strength and vibration isolation requirements.
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
This solution enhances vibration decoupling and guidance properties by preventing lateral movement and overloading, ensuring efficient operation and reduced component stress, while maintaining a simple structure with minimal components and small installation space.
Implementation Method 1
the motor unit (2) and the handle unit (3) are coupled to one another via several anti-vibration elements (11, 12, 13, 14)... the first anti-vibration element (11) which comprises a helical spring (20)
Data Source
Figure 1~3
Figure 4~6
Figure 7~9
AI summary
A hand-held power tool (1) comprises a motor unit (2) and a handle unit (3). The motor unit (2) includes a drive motor (10) for driving a tool of the power tool (1). The handle unit (3) includes a handle (7). The motor unit (2) and the handle unit (3) are connected to each other via at least one anti-vibration element (11, 12, 13, 14). A first anti-vibration element (11) comprises a coil spring (20). A first retaining element (21) is attached to a first end (24) of the coil spring (20). A second retaining element (22) is attached to a second end (25) of the coil spring (20). The first retaining element (21) is fixedly connected to the motor unit (3). The second retaining element (22) is fixedly connected to the handle unit (3). The retaining elements (21, 22) have end faces (31, 32) which are arranged in an interior (34) of the coil spring.The end faces (31, 32) of the retaining elements (21, 22) have centering elements (35, 36) that can come into contact with each other, thereby centering the retaining elements (21, 22) relative to each other. The end faces (31, 32) of the retaining elements (21, 22) form a stop for the movement of the handle (7).