Elastic Hinge Screw Retention via Tilting Blocking
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Solution Overview
Problem
Elastic hinges for eyeglass frames face issues with securely retaining the articulation screw after numerous opening and closing cycles, leading to loosening and unscrewing, which compromises mechanical strength and increases production costs.
Innovation Solution
The elastic hinge design features an articulation screw with an enlarged annular portion and a narrow annular portion, where the elastic device exerts a transverse force to maintain the screw in a blocking position, preventing further unscrewing even after 50,000 cycles by interfering with the internal edge of the articulation element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional articulation screws are used in elastic hinges, then the hinge can be manufactured with standard components, but the screw loosens and unscrews after numerous opening and closing cycles
Solution Approach 1:
The patent applies the dynamics principle by making the articulation screw tiltable relative to the hinge axis. The screw can tilt within a range of motion defined by the clearance between the narrow annular portion and the articulation element's hole. This dynamic positioning allows the screw to automatically adjust its angle during operation, enabling the enlarged annular portion to engage with the internal edge and prevent complete unscrewing after numerous cycles.
Solution Approach 2:
The patent uses the elastic device as an intermediary mechanism. The elastic device exerts a transverse force on the articulation screw, maintaining it in a blocking position where the enlarged annular portion interferes with the internal edge of the articulation element. This intermediary force prevents the screw from loosening and unscrewing during repeated opening and closing operations.
2Reliability
If the articulation screw is designed with enlarged and narrow annular portions, then the screw remains securely retained, but the manufacturing complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the articulation screw into distinct functional portions: a head portion, an enlarged annular portion, a narrow annular portion, and a threaded portion. Each segment serves a specific function—the narrow portion creates clearance for tilting, the enlarged portion provides blocking engagement, and the threaded portion enables screwing. This segmentation allows standard manufacturing processes to create each segment independently while achieving the overall complex function.
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 design ensures the articulation screw remains securely engaged, maintaining mechanical strength and preventing unscrewing, thus extending the hinge's lifespan and reducing production costs.
Implementation Method 1
the elastic device exerts a transverse force to maintain the screw in a blocking position, preventing further unscrewing
Data Source
AI summary
Elastic hinge for eyeglass frames, which comprises an articulation screw engaged in the holes of two articulation elements. The articulation screw comprises a shank provided with a narrow portion, which is engaged in the hole of a first tab of an articulation element, and with an enlarged annular portion, which forms a step and is engaged in the hole of a head portion of the other articulation element. The articulation screw assumes an end stop position, in which it is tightened and aligned with the hinging axis, and a blocking position, in which it is loosened and is tilted with respect to the hinging axis in response to the elastic force exerted by an elastic device, such that the step of the articulation screw interferes with the edge of the hole of the first tab of the articulation element, preventing a further unscrewing of the articulation screw.