Plastic Window Center Seal with Retaining Plate
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Solution Overview
Problem
Conventional plastic window center seals fail to achieve sufficient sealing properties without exceeding permissible contact forces, as they are either unsatisfactory in terms of required contact pressure and sealing effect or not adapted to the specific requirements of central seals.
Innovation Solution
A plastic window design featuring a stiff retaining plate with a soft sealing profile made of foamed EPDM, where the retaining plate is securely anchored in a groove and the sealing profile has a U-shaped design with a longitudinal cavity for enhanced deformation, allowing for high sealing effectiveness with low contact forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional lip seal is used for the center seal, then the sealing effect is improved with low contact pressure, but sufficient sealing properties cannot be achieved without exceeding permissible contact forces
Solution Approach 1:
The center seal combines a rigid retaining plate made of dimensionally stable EPDM with a soft sealing profile made of foamed EPDM. This composite structure allows the rigid plate to provide structural support and anchoring while the soft foamed profile delivers effective sealing with low contact pressure, resolving the contradiction between achieving sufficient sealing and avoiding excessive contact forces.
Solution Approach 2:
The seal is designed with different material properties in different regions: the retaining plate uses dense, dimensionally stable EPDM for structural integrity and anchoring in the groove, while the sealing profile uses soft, foamed EPDM for compliant contact and sealing. This local differentiation of material quality enables the seal to simultaneously maintain its position and provide effective sealing with low force.
2Device complexity
If a hollow profile seal is used as described in EP 0 881 350 A, then the sealing structure is simplified, but the seal is not adapted to the specific requirements of a central seal
Solution Approach 1:
Rather than using a uniform hollow profile seal, the invention applies different material densities and structures to different parts of the seal: the retaining plate uses dense dimensionally stable EPDM for anchoring, while the sealing profile uses soft foamed EPDM for sealing. This local quality differentiation adapts the seal to the specific requirements of center seal application while maintaining reasonable structural complexity.
3Reliability
If a soft sealing material is selected for the sealing profile, then the sealing effect is improved, but the retaining plate must provide sufficient rigidity for secure anchoring
Solution Approach 1:
The center seal is constructed as a composite of two EPDM materials with different properties: the retaining plate uses dimensionally stable (rigid) EPDM to provide secure anchoring in the groove, while the sealing profile uses soft foamed EPDM to deliver effective sealing. This composite material approach resolves the contradiction between requiring soft sealing material and needing a rigid retaining plate.
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 design achieves improved sealing performance with low contact forces, ensuring a secure and pressure-resistant seal while maintaining cost-effectiveness through the combination of dimensionally stable EPDM materials, and allows for easy cleaning and manufacturing.
Implementation Method 1
the soft sealing profile is made of foamed EPDM, with the holding plate and sealing profile preferably being coextruded. The soft sealing profile has a sealing nose on the side opposite the retaining plate. In this case, the sealing lug interacts with a sealing surface which is arranged essentially perpendicular to the holding plate.
Implementation Method 2
In particular, a cavity running in the longitudinal direction can be provided in the soft sealing profile in the area of the sealing lug. In this way, a particularly favorable deformation behavior of the seal is achieved.
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a plastic window comprising a wing profile (2) and a frame profile (21, 3) which are respectively designed as plastic hollow chamber profiles, and a central seal (23) which is placed on the frame profile (21, 3). The seal can be improved such that the central seal (23) is made from a solid retaining plate (25) on which a flexible weatherstrip (26) is formed.