Plastering Strip with Expansion Mechanism for Crack Prevention
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Solution Overview
Problem
The connection between plaster and window or door frames in building construction often results in cracks due to shrinkage and exposure to vibrations and temperature fluctuations, leading to moisture penetration and damage, especially when there is no suitable gap for a plastering strip.
Innovation Solution
A building corner design featuring a plaster strip with a base area and expansion strip positioned in front of thermal or sound insulation, fixed using nails, screws, or dowels, which expands to compensate for movements and creates a secure seal regardless of the gap size between the insulation and the building component.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If plaster is directly connected to window or door frames, then construction is simpler, but cracks and gaps appear due to shrinkage, vibrations, and temperature fluctuations
Solution Approach 1:
The patent introduces a plastering strip as an intermediary element between the plaster and the window/door frame. This strip includes an expansion strip that can move independently to absorb dimensional changes, preventing direct stress transmission that would cause cracking. The plastering strip acts as a buffer zone that decouples the rigid frame from the shrinking plaster.
Solution Approach 2:
The expansion strip within the plastering strip is designed to change its physical parameters (length, volume) in response to temperature fluctuations and vibrations. This parameter change allows the strip to maintain contact with both the frame and plaster while accommodating dimensional variations, preventing gap formation and moisture penetration.
2Reliability
If a plastering strip is used to ensure a secure seal, then reliability improves, but the solution becomes unsuitable when there is no or only a very small gap between the frame and thermal insulation
Solution Approach 1:
The plastering strip incorporates a dynamic expansion strip that can adjust its dimensions based on the available gap space. When a larger gap exists, the expansion strip extends to fill it; when the gap is small or nonexistent, the strip compresses or adheres directly to the frame surface. This dynamic adaptation allows the same solution to work across various construction scenarios.
Solution Approach 2:
The plastering strip features differentiated local properties: the expansion strip portion contacts the frame and accommodates movement, while the plaster leg portion bonds to the thermal insulation and provides a stable base for plaster attachment. This local quality differentiation allows the strip to function effectively regardless of the overall gap dimension between frame and insulation.
3Ease of manufacture
If the plastering strip is fixed directly to the thermal insulation, then attachment is simplified, but the seal quality deteriorates due to movements from vibrations and temperature changes
Solution Approach 1:
The plastering strip is segmented into distinct functional portions: an expansion strip for absorbing movements, a middle section for fixation to the thermal insulation, and a plaster leg for plaster bonding. This segmentation allows each portion to perform its specific function independently, with the expansion strip handling vibrations and temperature changes while the fixation portion remains stable.
Solution Approach 2:
The expansion strip acts as a mediator between the fixed thermal insulation and the movable plaster layer. It absorbs the effects of vibrations and temperature fluctuations before they can transmit stress to the plaster bond, thereby maintaining seal quality while keeping the attachment method simple.
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
The solution provides a reliable and permanent seal, reducing the risk of damage from moisture and improving sound-damping and vibration reduction between building components and insulation, suitable for situations with no or small gaps.
Implementation Method 1
an expansion strip (32) with expansion capability, which is designed to abut the building component
Implementation Method 2
since such building corners are also exposed to high temperature fluctuations, there is a risk that a crack or gap will appear
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The plastering strip (2) has a base region (4) and expansion strips (32) positioned before a heat/sound insulation unit relative to an extension direction of a building wall-opening. A plastic screw, a plug connector and a plastic nail extend into the heat/sound insulation unit through an opening in a plastering arm (8). The expansion strips lie at a window post, and is brought into an expansion release state from a blocking state by a user. A blocking region (30) prevents expansion of the expansion strips in the blocking state. The plastering arm is embedded in a plastering layer. An independent claim is also included for a building corner.