Scissor Locking Bolt Dynamics for Gap-Free Closure
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Solution Overview
Problem
Modern pruning shears, particularly anvil scissors, often experience light gaps between the cutting edge and anvil due to manufacturing tolerances and wear, leading to suboptimal cutting performance and user perception of defects, while existing locking devices cannot guarantee gap-free closure.
Innovation Solution
A locking device featuring a displaceable elongated locking bolt with a conical or cylindrical latching section that aligns precisely with a notch, allowing for adjustment to eliminate light gaps by pivoting and utilizing static friction to maintain a gap-free closed position, even with wear and manufacturing variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional locking devices with fixed tumblers are used, then the structure is simple, but they cannot guarantee gap-free closure due to manufacturing tolerances and wear
Solution Approach 1:
The locking bolt is designed to be displaceable along its longitudinal axis within a bore, transitioning between locked and unlocked positions. This dynamic capability allows the bolt to adjust to manufacturing tolerances and wear, ensuring gap-free closure while maintaining a relatively simple overall structure.
Solution Approach 2:
The locking bolt features a conical or truncated conical latching section that can be pressed into the locking notch. The conical geometry allows for parameter adjustment during the locking process, enabling the bolt to compensate for dimensional variations and ensure precise alignment without requiring overly complex adjustment mechanisms.
2Reliability
If the locking bolt is made displaceable to ensure gap-free closure, then closure precision improves, but the device complexity increases
Solution Approach 1:
The locking bolt is designed to be displaceable along its longitudinal axis within a bore, transitioning between locked and unlocked positions. This dynamic capability allows the bolt to adjust to manufacturing tolerances and wear, ensuring gap-free closure while maintaining a relatively simple overall structure.
Solution Approach 2:
The conical latching section of the locking bolt automatically aligns and engages with the locking notch through its own geometric properties. The conical shape guides the bolt into proper alignment as it moves axially, enabling self-alignment and ensuring reliable locking without requiring additional adjustment mechanisms or complex control systems.
3Manufacturing precision
If the locking bolt uses a conical latching section for precise alignment, then manufacturing precision is improved, but the ease of manufacture decreases
Solution Approach 1:
The locking bolt features a conical or truncated conical latching section that can be pressed into the locking notch. The conical geometry allows for parameter adjustment during the locking process, enabling the bolt to compensate for dimensional variations and ensure precise alignment without requiring overly complex adjustment mechanisms.
Solution Approach 2:
The conical or truncated conical shape of the latching section provides a curved surface that naturally guides alignment during the locking action. This curved geometry simplifies the manufacturing process compared to precision-machined flat surfaces with tight tolerances, as cones can be produced through standard turning or forging operations while still achieving the required alignment precision.
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
Ensures scissors remain locked without gaps, allowing for precise alignment and extended use without light gaps, enhancing cutting performance and user satisfaction.
Implementation Method 1
the locking bolt has a truncated cone section on one end facing the locking notch, and it is guided in two bore sections that are offset axially parallel in one plane, with one end of the locking bolt causing a rotary movement when it is axially displaced through the cone slope, around the center of its other spherical end
Implementation Method 2
the locking bolt has a truncated cone section on one end facing the locking notch, and it is guided in two bore sections that are offset axially parallel in one plane, with one end of the locking bolt causing a rotary movement when it is axially displaced through the cone slope, around the center of its other spherical end
Implementation Method 3
A locking device featuring a displaceable elongated locking bolt with a conical or cylindrical latching section that aligns precisely with a notch, allowing for adjustment to eliminate light gaps by pivoting and utilizing static friction to maintain a gap-free closed position
Data Source
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AI summary
The locking device has a shear shank (10) and another shear shanks (14) connected together by a pivot pin with a hand operating cutting head (28) and a locking pin operated by these, which locks the shear shanks in closing position against the force of an opening spring. The bolt is formed by longitudinally extending locking pin, which retracts in a bore (25) along its longitudinal axis in the shear shank such that a front detent section (31) of the locking pin is slided in the closed position of the shear in the detent notch (22).