Flexible Dowel Strand with Sleeve for Borehole Insertion
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Solution Overview
Problem
Conventional dowels require a borehole diameter larger than the screw diameter, necessitating a variety of dowels for different screw sizes and compromising on inherent dimensional stability, which can lead to buckling during insertion due to friction.
Innovation Solution
A method using a flexible strand of dowel material and a dimensionally stable sleeve, where the strand is pushed through the sleeve and into the borehole, allowing the sleeve to be withdrawn while restraining the strand, allowing one end to remain and form a dowel, optimizing anchor volume without high demands on strand stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a flexible strand of dowel material is used to optimize anchor volume and reduce borehole diameter, then the borehole diameter can be closer to the screw diameter, but the strand lacks inherent dimensional stability and buckles easily during insertion due to friction
Solution Approach 1:
A pushing element acts as an intermediary tool to insert the flexible strand into the borehole. The pushing element provides the necessary force to overcome friction and guide the strand through the borehole without the strand needing inherent dimensional stability. After insertion, the pushing element is removed, leaving the strand properly positioned in the borehole.
Solution Approach 2:
The strand's physical state is changed from requiring high dimensional stability to being insertable in a flexible state. The strand is designed to be flexible during insertion but expands or stabilizes after insertion to provide anchoring function. This parameter change allows the strand to be pushed into the borehole without buckling while still providing reliable anchoring.
2Stability of the object's composition
If conventional dowels with high dimensional stability are used, then the dowel can be inserted reliably into the borehole, but the borehole diameter must be larger than the screw diameter, requiring a variety of dowels for different screw sizes
Solution Approach 1:
The flexible strand can be used with screws of different diameters and lengths, making a single strand design universal for multiple screw sizes. The strand expands or deforms to accommodate different screw dimensions, eliminating the need for multiple dowel sizes and providing adaptability across different fastening applications.
Solution Approach 2:
The strand's physical properties change after insertion, allowing it to adapt to different screw sizes. The flexible material can be compressed during insertion and then expands or stabilizes to provide consistent anchoring for various screw diameters, enabling one strand design to serve multiple screw size requirements.
3Ease of operation
If the borehole diameter is made larger than the screw diameter to accommodate conventional dowels, then the dowel can be inserted and provide anchoring, but this increases drilling work and compromises structural stability
Solution Approach 1:
The borehole diameter parameter is reduced to be equal to or slightly larger than the screw diameter, matching the borehole size to the actual fastening element size. This parameter optimization reduces drilling work and minimizes structural compromise while the flexible strand's ability to deform during insertion compensates for the smaller borehole clearance.
Solution Approach 2:
The flexible strand acts as a thin, deformable element that can be inserted into a tightly-fitting borehole. The flexibility allows the strand to conform to the borehole walls and provide anchoring without requiring excessive clearance, enabling the use of smaller boreholes that preserve structural integrity while still allowing 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
Enables reliable, resilient anchoring with smaller boreholes, reducing drilling work and allowing for closer alignment of borehole and screw diameters, improving structural stability and eliminating the need for expensive manufacturing machines.
Implementation Method 1
The screw is clamped in the drill hole by means of the dowel, with the dowel functioning as an elastically or plastically deformed, force-distributing element.
Implementation Method 2
The screw is clamped in the drill hole by means of the dowel, with the dowel functioning as an elastically or plastically deformed, force-distributing element.
Implementation Method 3
If the inherent dimensional stability of the dowel is too low, the insertion of the dowel into the borehole causes difficulties because the dowel buckles easily due to friction effects.
Data Source
Figure 1~3
Figure 4a~4d
AI summary
The method involves preparing a line from a dowel material for preparing an elongated sleeve which is axially guided in a wall hole. The line is axially pushed through the wall hole for inserting the sleeve and the line in the wall hole. The line is pushed together with the sleeve to adjust in the wall hole. An independent claim is included for a kit for executing a dowel setting method.