Pruning Shear Flat Spring Fixation Mechanism
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Solution Overview
Problem
Existing pruning shears, such as secateurs, suffer from unsatisfactory fixation of the flat spring element, which can twist or become misaligned during opening and closing movements, leading to instability and potential dislodgment.
Innovation Solution
The shears incorporate a laminated or flat spring element with first and second supporting means to securely fix the spring element, preventing twisting and misalignment by using a U-shaped hook or bent end section interacting with the shaft or lever arm, and additional radial and axial supports to maintain the spring's position, ensuring firm fixation and ease of replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a flat spring element is used to provide opening force, then the shears can be automatically opened after cutting, but the spring element may twist or become misaligned during operation
Solution Approach 1:
The spring element is divided into a first portion (fixedly arranged at the first shear part) and a second portion (flexibly arranged acting on the second shear part). This segmentation allows the fixed portion to provide stable anchoring while the flexible portion maintains the opening force function, resolving the contradiction between ease of operation and reliability.
Solution Approach 2:
The first supporting means and second supporting means act as intermediary structures between the spring element and the shear parts. These supporting means prevent twisting and misalignment of the spring element while allowing it to perform its opening function, thus resolving the stability issue without compromising the automatic opening capability.
2Reliability
If the spring element is firmly fixed to prevent twisting and misalignment, then stability is improved, but the device complexity increases due to additional supporting means
Solution Approach 1:
The first supporting means and second supporting means are integrated into the existing shear part structures rather than being separate additional components. The first supporting means is formed on the first shear part, and the second supporting means is formed on the second shear part, merging the fixation function with the existing structure to minimize complexity increase.
Solution Approach 2:
The supporting means serve multiple functions: they provide fixation points for the spring element, prevent twisting and misalignment, and maintain the structural integrity of the shear parts. This multi-functionality reduces the need for separate dedicated fixation components, thereby limiting the increase in device complexity.
3Reliability
If the spring element is extended into the shear part to prevent movement, then fixation is improved, but the available space for spring movement is reduced
Solution Approach 1:
The spring element has different properties in different portions: the first portion is fixedly arranged with specific structural characteristics for stable mounting, while the second portion is flexibly arranged with appropriate length and curvature for maintaining opening force. This local differentiation allows the fixed portion to provide positioning stability while the flexible portion maintains sufficient movement capability.
Solution Approach 2:
The spring element's second portion is designed to be dynamically flexible, allowing it to bend and extend as needed during the opening and closing cycles. The supporting means provide fixed anchoring points while the spring portion between them can dynamically adjust its configuration, resolving the contradiction between positioning stability and movement space.
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 design provides a high-quality, stable tool with a secure spring fixation that prevents loosening and misalignment, enhancing operational reliability and ease of maintenance by ensuring the spring element remains firmly in place during use.
Implementation Method 1
a laminated or flat spring element which acts upon the first and second shear parts to move the shears on to their open position
Data Source
Figure 1~3
Figure 4~5
Figure 6
AI summary
The invention relates to shears, in particular pruning shears or secateurs (1), comprising a first shear part (3) and a second shear part (3'). Each of the first and second shear parts (3, 3') have a cutting blade (11, 11') and a shaft or lever arm (5, 5') which are arranged at opposite sides of a pivot (7) which rotatably connects the first and second shear parts (3, 3') with each other. The shears further comprise a laminated or flat spring element (27) acting upon the first and second shear parts (3, 3') to move the shears on to an open position. The laminated or flat spring element (27) comprises a first portion (27') fixedly arranged at or allocated to the first shear part (3) and a flexibly arranged second portion (27") acting on the second shear part (3'). In order to firmly fix the laminated or flat spring element (27), first supporting means (37) are provided supporting the laminated or flat spring element (27) in axial direction to prevent a movement of the laminated or flat spring element (27) towards the pivot (7). Further, second supporting means are provided supporting the first portion (27') of the laminated or flat spring element (27) in radial direction to prevent twisting and/or bending and/or radial movement of the first portion (27').