Composite Dowel Sleeve With Hard Inserts for Easy High-Load Anchoring
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Solution Overview
Problem
Existing dowels face challenges in achieving high anchoring force while ensuring easy and reliable insertion, particularly in substrates with smooth hole walls or delicate hollow bricks, due to the contradiction between the need for a soft sleeve for easy screwing and a hard sleeve for high load-bearing capacity.
Innovation Solution
A dowel design comprising a soft dowel sleeve and harder expansion inserts, where the expansion inserts are arranged to expand and form undercuts in the substrate, allowing for easy insertion and high anchoring force through differential plastic hardness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the anchor sleeve is made of hard plastic to achieve high load-bearing capacity, then the anchoring force is improved, but the screw-in torque is significantly increased making insertion difficult
Solution Approach 1:
The anchor sleeve incorporates hard plastic inserts at specific locations (expansion zones) rather than making the entire sleeve hard. These inserts provide localized hardness for high load-bearing capacity at the expansion interface, while the rest of the sleeve remains soft to allow easy screw insertion. This spatial differentiation of material properties resolves the contradiction between needing hardness for strength and softness for ease of operation.
Solution Approach 2:
The anchor sleeve is constructed as a composite structure combining soft plastic (base material) and hard plastic inserts (reinforcement). The soft plastic matrix provides ease of deformation and insertion, while the hard plastic inserts provide the necessary rigidity and load-bearing capacity. This composite approach allows simultaneous achievement of both softness for insertion and hardness for anchoring strength.
2Ease of operation
If the anchor sleeve is made of soft plastic to enable easy screw insertion, then the ease of operation is improved, but the load-bearing capacity is reduced
Solution Approach 1:
Rather than making the entire sleeve soft, the invention places hard plastic inserts at critical locations where load-bearing is most important (the expansion zones that contact the substrate). The soft plastic is retained in areas where ease of deformation is needed. This localized reinforcement strategy maintains overall softness for easy insertion while providing localized hardness for sufficient load-bearing capacity.
Solution Approach 2:
The composite construction combines soft plastic providing ease of operation with hard plastic inserts providing structural strength. The soft plastic matrix allows the sleeve to deform easily during insertion, while the embedded hard inserts ensure that once expanded, the anchor can bear significant loads. This material combination directly addresses the contradiction between softness and strength.
3Stability of the object's composition
If the anchor sleeve is made rigid to prevent rotation during screwing, then the stability is improved, but the torque required for insertion is significantly increased
Solution Approach 1:
The hard plastic inserts are strategically positioned to provide rotational stability at the expansion zones without making the entire sleeve rigid. The soft plastic portions of the sleeve can still deform to accommodate screw insertion with minimal torque. This localized rigidity provides sufficient anti-rotation stability while maintaining ease of operation during insertion.
Solution Approach 2:
The composite structure of soft plastic with hard plastic inserts creates a balance between flexibility and rigidity. The soft plastic allows the sleeve to be inserted with low torque, while the hard inserts provide the necessary resistance to rotation during the screwing process. This material combination resolves the contradiction between needing rigidity for stability and softness for ease of insertion.
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 design allows for easy screw insertion with minimal force, preventing screw shearing and chipping, while achieving high load-bearing capacity and stability in various substrates.
Implementation Method 1
designed to expand when the fastening element is inserted into the opening
Implementation Method 2
Through frictional engagement between the dowel and the surrounding material
Implementation Method 3
Through frictional engagement between the dowel and the surrounding material
Implementation Method 4
unfold the dowel to form an undercut in at least one cavity in the anchoring base
Data Source
Figure 1~2
Figure 3
AI summary
An anchor (100) comprising an anchor sleeve (102) made of a first plastic and having an opening (104) for inserting a fastening element, and a plurality of expansion inserts (106) made of a second plastic, which do not form a further anchor sleeve and are arranged on the anchor sleeve (102) and are designed to expand when the fastening element is inserted into the opening (104), wherein the anchor sleeve (102) forms all areas of the anchor with which the fastening element comes into contact when inserted into the opening (104) in order to press the anchor (100) in an anchoring base in contact with a wall of the anchoring base and/or to unfold the anchor (100) to form an undercut in at least one cavity in the anchoring base, wherein the expansion inserts (106) form areaswhich, when the fastening element is inserted into the opening (104), are pressed into contact with a wall of the anchoring base and/or fold out to form an undercut in at least one cavity in the anchoring base, and wherein the first plastic is softer than the second plastic.