Self-cutting Undercut Anchor Sliding Section Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing self-tapping undercut anchors require significant impact energy for expansion, which is inefficient and cumbersome.
Innovation Solution
A self-tapping undercut anchor design featuring an anchor bolt with a conical expansion body and a tubular expansion sleeve, where the expansion sleeve has a slotted section with cantilevered spreading elements and a sliding section with a reduced diameter, allowing for efficient undercut creation in the borehole wall with minimal impact energy by using a setting tool to push the expansion sleeve onto the expansion body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a conventional self-tapping undercut anchor is expanded using impact energy, then the expansion sleeve can be driven onto the expansion body to create an undercut, but a large amount of impact energy is required which is inefficient and cumbersome
Solution Approach 1:
The patent changes the geometric parameters of the expansion sleeve by introducing a sliding section with reduced diameter and an annular step. The sliding section has a diameter smaller than the expansion body, creating a stepped configuration. This parameter change allows the expansion sleeve to be pushed onto the expansion body with significantly reduced impact energy, as the sliding section acts as a guide and reduces friction during the expansion process.
Solution Approach 2:
The expansion sleeve is segmented into different sections with different diameters: a sliding section with reduced diameter and a main body section. This segmentation allows different parts of the expansion sleeve to perform different functions during expansion - the sliding section facilitates easy movement onto the expansion body while the main body creates the undercut. The segmentation resolves the contradiction by dividing the expansion process into low-energy positioning and high-energy cutting phases.
2Device complexity
If the expansion sleeve is designed without a sliding section, then the structure is simpler, but a large amount of impact energy is required for expansion
Solution Approach 1:
The patent introduces a sliding section with reduced diameter as a specific parameter change in the expansion sleeve design. This additional section, while increasing structural complexity, dramatically reduces the impact energy required for expansion. The sliding section acts as a transition zone that facilitates smooth engagement with the expansion body, reducing the energy barrier for expansion.
Solution Approach 2:
The sliding section with reduced diameter acts as an intermediary element between the expansion sleeve and the expansion body. It mediates the interaction by providing a reduced-friction interface during the initial engagement phase. This intermediary section allows the expansion sleeve to be pushed onto the expansion body with minimal impact energy before the main body engages to create the undercut.
3Productivity
If the annular step is positioned closer to the sliding section, then the undercut creation is more efficient, but the sliding section becomes shorter and less effective
Solution Approach 1:
The patent segments the expansion sleeve into distinct functional zones: a sliding section of optimized length and an annular step at its rear end. This segmentation allows the sliding section to provide sufficient guide length for low-friction engagement while the annular step positioned at the rear provides efficient undercut creation. The segmentation resolves the contradiction by assigning different functions to different portions of the expansion sleeve.
Solution Approach 2:
The patent optimizes the length of the sliding section and the position of the annular step as critical parameters. The sliding section is made sufficiently long to provide effective guidance and reduce friction during engagement, while the annular step is positioned at the rear end to maximize its leverage for undercut creation. This parameter optimization balances the competing requirements of sliding section length and undercut creation efficiency.
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 significantly reduces the required impact energy for expansion, improving the expansion behavior of the undercut anchor by utilizing the sliding section to adapt to the expansion body and the annular step to act as a chisel, creating an effective undercut with less effort.
Implementation Method 1
The sliding section is reduced in diameter compared to a rear part of the expansion sleeve in the insertion direction and/or compared to the part of the expansion section located behind the sliding section in the insertion direction
Implementation Method 2
at least one first annular step is arranged between the sliding section and the rear part of the expansion sleeve in the direction of insertion, which forms a first edge for engaging in a borehole wall of the borehole
Data Source
Figure 1~2
Figure 3a~3d
Figure 3e~3f
AI summary
The invention relates to a self-tapping undercut anchor (1) with an anchor bolt (2) and an expansion sleeve (3), which can be anchored in a borehole (12) by expanding the expansion sleeve (3). The undercut anchor (1) is designed such that a setting tool can be attached to the rear end (27) of the expansion sleeve (3) in the insertion direction (E) for expansion, and the expansion sleeve (3) can be pushed on by striking the expansion body (7), thereby expanding a slotted expansion section (13).To improve the expansion behavior of the undercut anchor (1), it is proposed that the expansion sleeve (3) has a sliding section (16) with a sliding element (20) at its front end in the insertion direction (E) and that at least one first ring step (17) is arranged between the sliding section (16) and an unslotted rear part (25) of the expansion sleeve (3), which forms a first edge (18) for engagement in a borehole wall of a borehole.