Expandable Strand Dowel for Reduced Drilling Power and Dust
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Solution Overview
Problem
Conventional dowels require larger drill holes, resulting in high drilling power and dust production, and necessitate a wide range of dowels for different screw diameters, leading to increased inventory needs.
Innovation Solution
A dowel composed of a strand arrangement with intersecting strands that can expand, allowing for uniform contact pressure distribution and use across various screw diameters, enabling smaller drill holes with reduced power and dust.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional dowels are used, then the drill hole diameter must be larger than the screw diameter, but this results in high drilling power requirements and increased drilling dust production
Solution Approach 1:
The dowel is designed with an expandable strand arrangement that transitions from a compact transport state to an expanded functional state within the drill hole. This dynamic expansion allows the dowel to initially fit through a smaller drill hole (reducing drilling power requirements) and then expand to provide adequate support, resolving the contradiction between precise hole sizing and power consumption
Solution Approach 2:
The dowel utilizes material parameter changes through its expandable strand construction, where the strands can be compressed during insertion and then expanded within the hole. This parameter transformation enables the dowel to pass through smaller holes with less drilling power while still providing sufficient anchoring strength after expansion
2Adaptability or versatility
If conventional dowels are used, then a broad range of dowel sizes must be kept in stock for different screw diameters, but this increases inventory complexity
Solution Approach 1:
The expandable strand arrangement dowel is designed as a universal fastening element that can adapt to multiple screw diameters and application requirements through its expansion capability. A single dowel design can serve multiple functions and size requirements, eliminating the need to maintain diverse inventory of different dowel sizes while maintaining adaptability across various fastening applications
Solution Approach 2:
The dynamic expansion capability of the dowel allows one size to fit multiple applications. The dowel can be inserted in a compact state through various drill hole sizes and then expanded to provide appropriate support for different screw diameters, replacing the need for multiple static dowel sizes in inventory
3Stress or pressure
If conventional dowels are used, then the contact pressure on the wall surface is concentrated, but this causes localized stress and potential damage
Solution Approach 1:
The dowel is constructed from multiple discrete strands arranged in a grid pattern rather than a solid continuous structure. This segmentation allows the contact pressure to be distributed across numerous individual strand contact points with the wall surface, preventing concentration of stress at any single location and reducing the risk of localized wall damage
Solution Approach 2:
The strand arrangement creates a porous or grid-like structure that inherently distributes loads across multiple contact points. This porous construction allows pressure to be dispersed throughout the dowel-wall interface rather than concentrated, mitigating localized stress effects on the wall surface
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 dowel can be used for multiple screw diameters, minimizing drilling dust and power, and reducing the need for multiple dowel sizes, enhancing versatility and efficiency.
Implementation Method 1
The strand arrangement is embodied in such a way and/or is made of such a material that said strand arrangement can be expanded at an angle to the longitudinal axis
Data Source
AI summary
The invention relates to a dowel that is composed of a strand arrangement comprising at least one first strand (12) which extends along a longitudinal axis (L) and at least one second strand (14) which extends at an angle (Y) to the at least one first strand (12) and intersects said at least one first strand (12) at intersection points. The at least one first strand (12) and/or the at least one second strand (14) is/are wound around the longitudinal axis (L) at a certain distance (171, 172) while the at least one first strand (12) is connected to the at least one second strand (14) at the intersection points. The strand arrangement is embodied such and/or is made of such a material that the strand arrangement can be expanded at an angle to the longitudinal axis (L). Such a dowel has the particular advantage of evenly distributing the pressure which acts upon the wall surface (102) of a bore. A single-size dowel can be used for several screw diameters. Furthermore, the amount of boring dust produced is significantly reduced, less power is required for drilling the bore, and the feed force applied to the drill can be decreased because a bore with a comparatively small diameter can be created.