Scissor Pivot Assembly with Non-Circular Rod for Easy Assembly
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Solution Overview
Problem
Conventional scissors are inconvenient to assemble due to the aesthetic issues with the pivot assembly and the difficulty in precisely positioning the locking block, leading to challenges in manufacturing and assembly.
Innovation Solution
The design features non-circular and circular pivotal segments in the pivot assembly and an inclined engaging mechanism in the locking device, allowing for secure and easy assembly by preventing rotational and axial movement of the pivot rod and enabling the locking block to be assembled in any direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a threaded rod and nut are used in the pivot assembly, then the blades and handles can be pivotally connected, but the appearance becomes non-aesthetic and the assembly becomes inconvenient due to rotation and axial movement
Solution Approach 1:
The pivot rod uses a non-circular cross-section (such as square or rectangular) instead of a circular one. This asymmetric shape prevents rotational movement when inserted into the pivotal holes, eliminating the need for additional locking mechanisms and improving both appearance and assembly convenience while maintaining reliable pivotal connection
2Reliability
If the locking block has only one single engaging portion, then it can be engaged with the rail, but the assembly becomes inconvenient and requires precise positioning
Solution Approach 1:
The locking block is equipped with multiple engaging portions (at least two) instead of a single one. These multiple engaging portions allow the locking block to be assembled onto the rail in any direction without requiring precise positioning, making the assembly process more convenient while maintaining reliable locking engagement
Data Source
AI summary
A pair of scissors has two handles, two blades, and a pivot assembly. The handles are connected with each other and respectively have a pivotal hole. The blades are pivotally connected with each other, are connected respectively with the handles, and respectively have a pivotal hole. The pivot assembly is mounted in the pivotal holes in the handles and the blades to pivotally connect the handles and the blades with each other and has a pivotal rod. The pivotal rod has two pivotal segments. Each pivotal segment has a cross section. One of the pivotal segments has a non-circular cross section and the other pivotal segment has a circular cross section. The pivotal holes in the handles and the blades are same in shape as the cross section of the pivotal segments respectively.