Self-Retractable Center Pin for Composite Assembly Alignment
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Solution Overview
Problem
Conventional alignment methods using pins in determinant assembly alignment holes face challenges in easy removal due to tight fits, often requiring hammering which can be undesirable for composite materials and ergonomically unfavorable.
Innovation Solution
A self-retractable centering assembly comprising a center pin with a threaded portion, a puller bushing, and a drive component that allows the center pin to slide and retract by rotating the drive component relative to the center pin, with a limiter controlling the sliding distance, enabling easy removal without impact tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional pins are used with tight fit in alignment holes, then precise alignment of parts is achieved, but removal of pins becomes difficult requiring hammering
Solution Approach 1:
The pin is divided into two functional segments: an insertion portion for alignment and a handle portion for removal. The insertion portion maintains tight fit for precision, while the handle portion extends perpendicular to provide leverage for easy removal without hammering
Solution Approach 2:
The handle is extended in a direction perpendicular to the insertion portion, adding a spatial dimension for removal operations. This allows operators to apply rotational force and leverage in a different plane, enabling easy extraction of the tightly-fitted pin without impact tools
2Ease of operation
If hammering is used to remove pins, then pin removal is achieved, but concentrated force spikes damage composite parts
Solution Approach 1:
The extended handle acts as an intermediary mechanical advantage device between the operator and the pin. It converts rotational motion into controlled linear extraction force, distributing stress evenly along the pin-hole interface rather than concentrating force at impact points
Solution Approach 2:
The invention replaces the impact-based removal mechanism (hammering) with a rotational extraction mechanism using the extended handle. This substitutes high-force impact loading with controlled torque application, eliminating force spikes that damage composite materials
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 solution allows for the simple and uniform removal of center pins from alignment holes, preserving the integrity of the parts and the assembly, without the need for hammers or impact tools, thus reducing stress on the aligned parts.
Implementation Method 1
The drive component is rotatably coupled to the puller bushing. The center pin protrudes through the puller bushing and can slide with respect to the puller bushing when the drive component is rotated relative to the center pin
Implementation Method 2
The tight fit of these pins in the holes ensures precise alignment of the holes... Hammering is needed to overcome the high friction forces between the pins and alignment holes associated with the tight fit
Data Source
Figure 1A
Figure 1B~1C
Figure 2A~2B
AI summary
Provided are self-retractable centering assemblies and methods of using these assemblies for alignment of parts having determinant assembly alignment holes. An assembly includes a center pin having a threaded portion threadably engaging a drive component. The assembly also includes a puller bushing rotatably coupled to the drive component. The center pin protrudes through the puller bushing and can slide with respect to the puller bushing when the drive component is rotated relative to the center pin. The sliding distance is controlled by a limiter disposed within the cavity of the puller bushing. During operation, a portion of the center pin extends from the puller bushing and is inserted into alignment holes of parts being aligned. The drive component is rotated relative to the center pin resulting in the center pin being pulled out of the alignment holes while the puller bushing is being pressed against the parts.