Expansible Rawplug Anchorage via Arm Segmentation and Tooth Density
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Solution Overview
Problem
Existing expansible rawplugs struggle to achieve strong anchorage in both solid and hollow walls due to inadequate friction and knot formation, leading to instability and risk of detachment, especially in solid materials where high force is required and in hollow materials where knot formation is difficult.
Innovation Solution
The rawplug design features a diameter-to-tooth-distance ratio of 3:4, with two arms toothed along their length and the other two toothed only on the half closest to the end, increasing the contact surface and anchorage capacity, and facilitating knot formation in hollow materials by allowing for a larger number of teeth and greater deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the rawplug has a larger diameter to improve anchorage in solid walls, then friction anchorage is improved, but the number of teeth decreases making knot formation difficult in hollow walls
Solution Approach 1:
The rawplug body is divided into multiple expansion arms (typically 4 arms) that can expand independently. Each arm is equipped with multiple teeth along its length, allowing the rawplug to provide both sufficient friction anchorage through the distributed teeth and effective knot formation in hollow walls through the segmented expansion structure.
Solution Approach 2:
Different regions of the rawplug are designed with different tooth configurations. The expansion arms have teeth distributed along their lengths, with specific tooth density and positioning optimized for different functions: friction anchorage in solid walls and knot formation in hollow walls. This local differentiation allows the same rawplug to excel in both wall types.
2Reliability
If the rawplug has more teeth to improve anchorage in hollow walls, then knot formation is facilitated, but the contact surface area with the wall decreases reducing friction anchorage
Solution Approach 1:
The rawplug is segmented into multiple expansion arms, each carrying a portion of the teeth. This segmentation allows the teeth to be distributed across the expanded structure, providing sufficient tooth count for knot formation while maintaining adequate contact surface area between the arms and the wall for friction anchorage.
Solution Approach 2:
The rawplug transitions from a compact cylindrical form to an expanded star-like configuration with multiple arms. This dimensional change allows teeth to be positioned along the length of each arm, increasing the effective number of teeth in contact with the wall while the arms themselves provide the necessary contact surface area for friction anchorage.
3Strength
If the rawplug is expanded strongly to improve anchorage, then friction anchorage in solid walls is improved, but the force required for installation increases
Solution Approach 1:
The rawplug is designed with dynamic expansion characteristics where the expansion arms progressively engage with the wall during insertion. The tooth configuration and arm geometry are optimized to provide gradual expansion, reducing peak installation forces while ensuring strong final anchorage through friction between the expanded arms and the wall.
4Ease of manufacture
If the rawplug has uniform teeth distribution to simplify manufacturing, then production is easier, but anchorage performance in different wall regions is insufficient
Solution Approach 1:
The rawplug features non-uniform tooth distribution across different expansion arms and along the arm lengths. Some arms have teeth distributed along their entire length while others have teeth concentrated in specific regions. This local quality differentiation optimizes anchorage performance for different wall types and regions, with manufacturing processes designed to accommodate these variations.
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 enhances resistance to detachment and anchorage efficiency by increasing the contact surface area and deformation capacity, ensuring stable fixation in both solid and hollow walls with reduced force requirements.
Implementation Method 1
In solid walls the expansible rawplug is fixed by means of friction between the wall and the teeth of the rawplug
Implementation Method 2
In walls made of hollow material the expansion arms of the rawplug deform, in a deformation caused by the expansion of rawplug due to insertion of the bolt into an interior whose diameter is smaller than its own, creating a knot inside the material
Data Source
Figure 1~4
AI summary
Expansible rawplug for walls and the like whose ratio between diameter and the distance between two adjoining teeth is between 2.5 and 4.5, and whose end inside the wall in the longitudinal direction of the rawplug devoid of teeth is equal to or less than the diameter, thus improving its anchorage conditions, both in walls made of solid materials and walls made of hollow materials.