Curved Injection-Molded Guide Rail Without Draft Angles
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Solution Overview
Problem
Existing methods for manufacturing guide rails for motor vehicle sliding windows, such as extrusion and injection molding, struggle to produce curved rails with C-shaped cross sections and relief angles, making it difficult to achieve precise control over the shape and surface of the hollow interior, which is crucial for precise guidance of sliding pads.
Innovation Solution
A guide rail with a tubular profile having a recess and a longitudinal slot, manufactured using an injection molding process, where the mold includes a male and female part with a core that forms the recess and slot, allowing for curved designs and extraction along an arc trajectory, enabling the production of curved guide rails without draft angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If extrusion process is used to manufacture guide rail, then production capability is achieved, but the rail can only be straight or very slightly curved
Solution Approach 1:
The patent changes the fundamental manufacturing parameter from extrusion to injection molding, enabling the production of curved guide rails with complex cross-sections while maintaining design flexibility. The injection molding process allows the mold cavity to be shaped according to the desired curved geometry, directly forming rails with various curvature radii and C-shaped cross-sections in a single operation.
2Shape
If injection molding is used to produce guide rail, then complex curved shapes can be achieved, but the rail cannot be directly demolded due to lack of draft angles
Solution Approach 1:
The patent divides the mold into two separate drawers (movable mold halves) that can move relative to each other along the curved trajectory. This segmentation allows the mold to open and extract the curved guide rail without requiring draft angles on the rail itself, as the demolding action is achieved through the relative movement of the two mold halves rather than through traditional draft angle geometry.
Solution Approach 2:
The patent introduces a new dimension of movement by configuring the mold drawers to move along a curved trajectory rather than in straight lines. This curvilinear demolding path allows the mold to successfully extract the curved guide rail without draft angles, transforming the demolding problem from a geometric constraint into a kinematic solution.
3Volume of stationary object
If hollow injection techniques (PIT, WIT, GIT) are used, then hollow bodies can be created, but precise control of internal shape and surface finish is not achieved
Solution Approach 1:
The patent introduces a core as an intermediary element within the mold cavity that directly forms the hollow interior of the guide rail. This core acts as a mediator between the injection process and the final hollow structure, allowing precise control of the internal shape and surface finish. The core is positioned and secured within the mold, and its surface geometry directly determines the internal geometry of the molded rail, enabling high precision internal features.
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 solution allows for the precise manufacturing of curved guide rails with C-shaped cross sections, facilitating the guidance of sliding windows by ensuring accurate demolding and integration with structural profiles, enhancing the functionality and assembly of motor vehicle door components.
Implementation Method 1
a device for injecting under pressure inside said molding cavity, plastic material intended to manufacture said guide rail
Implementation Method 2
an extraction device configured to move said core from one of the two ends of the molding cavity along an arc trajectory
Data Source
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AI summary
The present invention relates to a guide rail, a device and a method for manufacturing same. This rail (1) is characterised in that it is made of injected plastic and in that it comprises at least one portion in the form of a tubular profile (10) which is longitudinally split over at least a portion of the length thereof. This rail can be straight or curved in the shape of an arc of a circle.