Freewheel Section Rotating Pin Thread Engagement
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Solution Overview
Problem
Existing rotating pins face mechanical impairment and spring element fatigue due to radial deflection of threaded elements, leading to inconsistent thread engagement and potential lead advancement issues, especially after long storage periods or at elevated temperatures.
Innovation Solution
A rotating pin design featuring a freewheel section with an outer diameter matching the core diameter of the external thread, preventing radial movement of threaded elements and maintaining consistent thread engagement, combined with wedge-shaped control cams for precise lead advancement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the threaded spindle is automatically rotated during assembly to achieve rear end position, then assembly efficiency is improved, but the threaded element may be located at the front end of a thread turn causing mechanical impairment
Solution Approach 1:
The patent designs the external thread with a specific configuration where the front end of the external thread is followed by a cylindrical spindle section (freewheel section) that extends over the entire spindle circumference. This preliminary structural arrangement ensures that even if automatic rotation during assembly doesn't achieve perfect positioning, the threaded element will engage with the thread groove without mechanical impairment, as the freewheel section provides a buffer zone that prevents over-rotation damage.
2Reliability
If the threaded element is pressed into the thread groove with radial force, then thread engagement is improved, but the spring element supporting the threaded element suffers fatigue over time
Solution Approach 1:
The patent changes the geometric parameters of the external thread by providing a cylindrical spindle section (freewheel section) with an outer diameter corresponding to the core diameter of the external thread. This parameter change creates a section where no thread grooves are present, allowing the threaded element to rest without radial compression, thereby reducing spring element fatigue while maintaining adequate thread engagement in the functional threading sections.
3Reliability
If the threaded element is allowed to deflect radially to avoid mechanical damage, then mechanical impairment is prevented, but thread engagement consistency deteriorates
Solution Approach 1:
The patent applies local quality by creating different structural zones along the spindle: the external thread sections provide engagement functionality, while the cylindrical spindle section (freewheel section) provides a non-threaded zone with different mechanical properties. This local differentiation allows the threaded element to have controlled radial deflection in the freewheel section without compromising thread engagement consistency in the threaded sections, as each zone performs its specific function optimally.
Data Source
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AI summary
The invention relates to a pivot pin with a sleeve-shaped shaft (1) having a front and a rear end, a threaded spindle (3) mounted therein so as to be axially movable and rotationally fixed, the spindle having at least a single-start external thread (7), and at least one threaded element (23) fixed to the shaft (1) in the axial and rotational direction and engaging the external thread. A cylindrical spindle section extending over the entire circumference of the spindle, namely a freewheel section (34), is connected to the front end of the external thread (7), the outer diameter (36) of which corresponds to the core diameter (37) of the external thread (7).