Self-Tapping Plastic Embossment With Tapered Pockets for Easy Demolding
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Solution Overview
Problem
The existing methods for forming embossments on injection-molded parts require additional tooling and mechanisms, increasing molding costs and complicating the demolding process, especially when embossments are formed perpendicular to the demolding direction.
Innovation Solution
The design includes a molded part with a cylindrical embossment featuring axially spaced, diametrically opposed pockets with inwardly tapered walls, allowing for self-tapping screw connections without the need for extra sliders or hydraulic mechanisms, as the pockets are defined by the molding tool itself, facilitating easier demolding and reduced manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If extra tooling such as sliders or lifters is used to form embossments, then the shape and structure of embossments can be defined, but molding costs increase
Solution Approach 1:
The patent combines the embossment formation function with the main molding tool by integrating sliders that are part of the mold assembly itself. The sliders are moved by spring mechanisms and cam surfaces that are built into the mold, merging the embossment formation mechanism with the primary molding tool rather than using separate external tooling.
Solution Approach 2:
The mold assembly is designed to perform multiple functions: the main molding cavity forms the basic part geometry, while integrated sliders form the embossments, and spring mechanisms provide both ejection force and slider actuation. This multi-functional design eliminates the need for separate dedicated tooling for embossment formation.
2Ease of operation
If hydraulic cylinders are used to withdraw sliders, then sliders can be removed from molds, but device complexity increases
Solution Approach 1:
The slider withdrawal mechanism uses springs that are pre-loaded during mold closing. When the mold opens, the spring force automatically pushes the sliders outward to withdraw them from the embossments. The system serves itself by using the mold closing action to compress springs that then perform the withdrawal function during mold opening, eliminating external hydraulic systems.
Solution Approach 2:
The patent uses dynamic spring mechanisms that automatically adjust slider position based on mold state. The springs are compressed during mold closing and expand during mold opening to withdraw sliders. This dynamic, self-regulating mechanism replaces static, externally-controlled hydraulic systems with a responsive, automatic system.
3Reliability
If embossments are formed perpendicular to demolding direction, then connection functionality is achieved, but demolding difficulty increases
Solution Approach 1:
The patent resolves the demolding conflict by adding a lateral dimension to slider movement. Instead of trying to demold perpendicular embossments in the vertical direction (which causes interference), the sliders move horizontally perpendicular to the demolding direction to form and withdraw from the embossments. This dimensional separation allows the embossment formation to occur in one dimension while demolding proceeds in another.
Data Source
AI summary
A molded part includes a plurality of surfaces and an embossment extending from one of the plurality of surfaces. The embossment includes a body and a bore extending through a central portion of the body. The embossment further includes a first pocket extending through a sidewall of the body and into the bore and a second pocket extending through an opposite sidewall of the body and into the bore. The first pocket and the second pocket each define inwardly tapered walls. The first pocket and the second pocket are spaced axially along the body and are diametrically opposed.