Composite Link Rods with Screwed Inserts via Filament Winding
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Solution Overview
Problem
Existing methods for manufacturing composite connecting rods with screwed inserts are either too expensive for low-load applications or inefficient due to the need for custom mandrels and varying thread diameters, which reduce the maximum buckling load.
Innovation Solution
A process involving a cylindrical metal mandrel and rings with external threads, where pre-impregnated fibers are wound and polymerized around the mandrel and rings, allowing for the production of connecting rods with constant diameter threads, enabling high production capacity and reduced manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a mandrel is used to wind pre-impregnated fibers for heavy load connecting rods, then the connecting rod can handle significant loads, but the manufacturing cost increases due to the requirement of prior fabrication of a custom mandrel
Solution Approach 1:
The patent applies universality by using a standardized mandrel that can produce connecting rods of various lengths and diameters through adjustable positioning of inserts and fiber winding parameters. This single universal mandrel replaces the need for custom-made mandrels for each product variation, significantly reducing tooling costs while maintaining the ability to manufacture high-strength connecting rods for heavy load applications
Solution Approach 2:
The patent utilizes parameter changes by adjusting the positioning of inserts along the mandrel and modifying the fiber winding parameters (layers, density, orientation) to produce connecting rods with different lengths, diameters, and strength characteristics. This allows a single mandrel to accommodate multiple product specifications without requiring physical modification of the mandrel itself
2Ease of manufacture
If flared threads are used in the connecting rod body, then the thread can be formed, but the external dimensions increase significantly and the maximum buckling load capacity is reduced
Solution Approach 1:
The patent applies inversion by forming the thread on the insert rather than on the composite connecting rod body itself. The insert is manufactured with external threads that screw into the composite tube, eliminating the need for flared internal threads in the composite structure. This approach maintains constant external dimensions of the connecting rod body while achieving secure threaded connection through the separately threaded insert
3Manufacturing precision
If custom tooling is manufactured for each connecting rod variation, then the specific dimensions can be achieved, but the production efficiency decreases and manufacturing costs increase
Solution Approach 1:
The patent implements universality through a standardized mandrel system that can produce multiple connecting rod variations by adjusting insert positioning and fiber winding parameters. This single tooling platform replaces numerous custom tooling sets, dramatically improving production efficiency and reducing tooling costs while maintaining precise dimensional control through programmable positioning systems
Solution Approach 2:
The patent applies dynamics by making the tooling system adjustable and reconfigurable. The mandrel allows dynamic repositioning of inserts along its length and adjustable fiber winding parameters, enabling the same physical tooling to adapt to different product specifications. This dynamic flexibility eliminates the need for static custom tooling for each variation while preserving manufacturing 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
This method enables the cost-effective production of connecting rods with maximized buckling load capacity and constant diameter threads, suitable for both high and low-load applications, while eliminating the need for custom tooling and reducing external size, thus enhancing industrial scalability.
Implementation Method 1
Bake the assembly consisting of the mandrel, bushings, and pre-impregnated fibers to polymerize the resin
Data Source
Figure 1~4
Figure 5~9
Figure 10
AI summary
The present invention relates to a method for manufacturing a link rod with screwed inserts (8), comprising the following steps: - making available a mandrel (1) and a plurality of rings (2) having an external thread (2b), - positioning said rings (2) in a spaced-apart manner along the length of the mandrel (1), - placing preimpregnated fibres (3) on the mandrel (1) and the rings (2) by filament winding, - curing the assembly formed by the mandrel (1), the rings (2) and the preimpregnated fibres (3), - removing the mandrel (1) so as to obtain a tube (4), - cutting the tube (4) at the rings (2) so as to obtain a link-rod body (5) with a portion of ring (2) at each end, - removing the portions of rings (2) from each end of the tube (4) so as to form a link-rod body (5) with an internal thread (6) at each end, - screwing on an insert (7) at each internal thread (6).