Aluminium Frame Interlock Corner with Pre-tensioning Mechanism
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Solution Overview
Problem
Aluminium frames with small cross-sections or long lengths often exceed their plastic deformation limit, leading to instability due to bending, which affects mechanisms like autonomous shading systems and sliding frames for mosquito screens.
Innovation Solution
An interlock angle with a pre-tensioning mechanism is used, where metallic angles with internal pre-tensioning mechanisms compress metal blades to counteract deformation, and the design includes grooves to prevent glue from interfering with the mechanism, allowing for inspection and screwing after drying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If small cross-section aluminium frames are used, then material usage is reduced and weight is decreased, but the frames exceed their plastic deformation limit and bend under load
Solution Approach 1:
The patent combines aluminium profile with internal steel reinforcement elements (blades) and metallic angles with pre-tensioning mechanisms to create a composite structure. This allows the frame to maintain low weight while gaining the high strength properties of steel reinforcement, resolving the contradiction between lightweight construction and structural strength.
Solution Approach 2:
The reinforcement system is divided into discrete components: metallic angles at joints, internal steel blades within profile chambers, and pre-tensioning mechanisms. This segmentation allows each component to be optimized independently and assembled into a complete reinforcement system that prevents bending while maintaining lightweight construction.
2Length of stationary object
If long length aluminium frames are used, then span capability is increased, but the frames bend under load causing instability
Solution Approach 1:
The pre-tensioning mechanisms are installed and activated before the frame is put into service. This preliminary action creates initial compressive forces in the aluminium profile that counteract the tensile bending stresses that will develop under load, allowing long spans to maintain stability without excessive deflection.
Solution Approach 2:
The patent changes the stress state parameter of the aluminium profile from purely tensile under load to a combination of initial compressive pre-stress and operational tensile stress. This parameter change allows the frame to withstand longer spans by keeping the net stress below the plastic deformation limit throughout the service life.
3Strength
If metallic angles with pre-tensioning mechanism are placed inside the frame, then frame stiffness is increased, but the mechanism requires space inside the profile
Solution Approach 1:
The pre-tensioning mechanism is nested within the existing internal chambers of the aluminium profile. The metallic angles and pre-tensioning devices are placed inside the profile's hollow sections, utilizing the available internal volume efficiently. This nesting approach provides reinforcement without requiring additional external space.
4Strength
If grooves are added to the angle for glue distribution, then bonding is improved, but the pre-tensioning mechanism becomes inaccessible for inspection and screwing
Solution Approach 1:
The angle is designed with differentiated zones: grooves in the bonding area to improve glue distribution and adhesion, while the pre-tensioning mechanism area remains smooth and accessible. This local differentiation allows the angle to simultaneously achieve strong bonding where needed and maintain accessibility where mechanical adjustment is required.
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 provides reinforced stiffness in narrow cross-sections without additional space, protects the mechanism from wear and rust, and reduces the need for support columns, ensuring stability in aluminium frames.
Implementation Method 1
All angles or some of them have a pre-tensioning mechanism inside, while pre-tensioning metal blades are placed in the interior chambers of the sides that make up the frame. The metal angles with their pre-tensioning mechanism compress the metal blades, which, by means of a spacer, curve in a direction opposite to the deformation of the side of the frame
Implementation Method 2
The metal angles with their pre-tensioning mechanism compress the metal blades, which, by means of a spacer, curve in a direction opposite to the deformation of the side of the frame, forcing it to return to its original position
Implementation Method 3
The present invention of a pre-tensioning-interlock angle has grooves which spread the glue over and around the surface of the angle so that the angle is glued to the profile
Data Source
Figure 1
Figure 2a~2e
Figure 3
AI summary
The sides of the frame are joined to each other by metal pre-tensioning angles (1) with pre-tensioning base (2), which bare pre-tensioning mechanism inside them, at the same time, metal pre-tensioning blades (12) with spacer (13) are placed inside the inner chambers of the sides which make up the frame. The metal angles (1) are screwed and the pre-tensioning bases (2) compress the metal blades (12), which, by means of the spacer (13), curve in opposite direction to the deformation of the side of the frame, thus forcing the frame to return to its original position, thereby balancing the deformation.