Plastic Sliding Sleeve With Circumferential Rib Prevents Axial Movement
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Solution Overview
Problem
Existing plastic sliding sleeves for pipe connections experience undesirable relative axial movement under extreme conditions, leading to a lack of secure and pressure-tight connections.
Innovation Solution
A plastic sliding sleeve with a circumferential rib protruding beyond its inner circumference, which can be integrated into the outer wall of the pipe end piece, preventing movement and allowing for simpler injection molding without undercuts, thereby enhancing manufacturing efficiency and tool durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a plastic sliding sleeve is used for pipe connection, then connection is achieved, but under extreme conditions relative axial movement occurs between the sliding sleeve and pipe end section
Solution Approach 1:
Instead of providing grooves or recesses in the sliding sleeve that would create undercuts requiring complex molding tools, the invention inverts the approach by providing a protruding circumferential rib on the sliding sleeve that engages with the pipe outer wall. This inversion eliminates the need for complex tooling while achieving the same anti-rotation and positioning function.
Solution Approach 2:
The invention addresses the axial movement problem by adding a circumferential rib that extends in the radial dimension beyond the inner circumference of the sliding sleeve. This radial extension creates engagement with the pipe outer wall, preventing axial movement without requiring complex axial or circumferential features that would create undercuts.
2Reliability
If inner profiles with undercuts are provided in the sliding sleeve to prevent movement, then connection stability is improved, but manufacturing complexity and tool cost increase
Solution Approach 1:
The invention inverts the conventional approach by placing the engagement feature (circumferential rib) on the outer surface of the sliding sleeve rather than creating grooves or undercuts on the inner surface. This inversion allows the feature to be formed by simple chamfering of the mold halves without requiring complex undercut removal mechanisms.
Solution Approach 2:
The circumferential rib can be divided into multiple circumferential rib sections that are offset from one another, making it easier to slide onto the pipe and distribute engagement points. This segmentation also simplifies the molding process by allowing each section to be formed independently by the chamfered mold surfaces.
3Reliability
If a circumferential rib with large overhang is provided to ensure securing, then axial movement is prevented, but manufacturing precision requirements and potential catching increase
Solution Approach 1:
The invention uses a circumferential rib with a relatively small overhang (maximum 150 μm, preferably maximum 30 μm) that is sufficient to prevent axial movement under normal operating conditions. This partial action approach avoids the need for large overhangs that would increase manufacturing difficulty and risk of catching, while still achieving the required securing function.
Solution Approach 2:
The small overhang of the circumferential rib provides just enough engagement to prevent axial movement without creating excessive force concentration or risk of catching. This cushioning effect allows reliable connection while maintaining ease of sliding during installation.
Data Source
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AI summary
A plastic sliding sleeve (3) is used for sliding it onto a connecting piece (2) and for fixing a pipe end piece (5) in a clamping way to the connecting fitting in a clamping position. The sliding sleeve (3) comprises an inner wall (10) that can be applied at least in sections to an outer wall of the pipe end piece (5) in the clamping position. The inner wall (10) comprises at least one circumferential rib (13) which protrudes toward the inside over the remaining inner wall (10) and runs at least along a section of an inner circumference of the sliding sleeve (3). A sliding sleeve is obtained, with which an undesired relative movement between the sliding sleeve and the pipe end section is prevented.