Deformable Retainer Arms for Self-Drilling Rock Anchors
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Solution Overview
Problem
Self-drilling rock anchors are less practical for holes drilled above horizontal due to the initial anchor rod tendency to fall out under its own weight before additional sections can be coupled, making installation inefficient and less common in such orientations.
Innovation Solution
A retainer device with a body portion and deformable arms or tabs that engage the anchor rod and the hole's inner surface, preventing movement and ensuring the anchor rod remains in place during installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If self-drilling rock anchors are used in above-horizontal holes, then installation efficiency is improved, but the anchor rod falls out under its own weight before additional sections can be coupled
Solution Approach 1:
The retainer device is pre-installed on the anchor rod before drilling, and automatically engages with the hole wall upon insertion to prevent the anchor rod from falling out. This preliminary positioning ensures the anchor rod remains retained during subsequent coupling operations without requiring additional retention steps.
Solution Approach 2:
The retainer device acts as an intermediary between the anchor rod and the hole wall, providing a mechanical connection that prevents the anchor rod from falling out. The retainer's deformable arms or tabs mediate the interaction by engaging the hole wall to support the anchor rod weight during installation.
2Reliability
If traditional cable bolts are used instead of self-drilling anchors, then anchor retention is ensured, but installation time increases and safety risks arise
Solution Approach 1:
The retainer device combines the functions of anchor rod support and hole wall engagement into a single integrated component. This merging eliminates the need for separate retention devices or procedures, reducing installation steps and time while maintaining reliable anchor retention.
Solution Approach 2:
The retainer device is designed to automatically engage with the hole wall upon insertion of the anchor rod, without requiring manual adjustment or additional operations. The deformable arms or tabs self-activate to provide retention, making the installation process faster and safer while ensuring reliable anchor retention.
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 safe and efficient installation of self-drilling anchors in above-horizontal holes, providing a faster and safer alternative to traditional cable bolts, with potential time savings and improved operational safety.
Implementation Method 1
the at least one arm or tab is configured to deform so as to engage and bear against the inner surface of the hole when the retainer device mounted on the anchor rod is driven into the hole
Data Source
AI summary
The present invention provides a retainer device 1 for retaining or holding an anchor rod 11 of a rock anchor, especially a self-drilling anchor, in a hole H drilled above horizontal. The retainer device 1 comprises: a body portion 2 configured to be mounted on the anchor rod 11, e.g., on an outer or external periphery of the anchor rod, and at least one locking arm or tab 6, 7 that projects from the body portion 2 in a direction transverse to a longitudinal extent of the anchor rod 11. The body portion 2 is configured to engage an abutment or shoulder on the outer or external periphery of the anchor rod to prevent its movement relative to the anchor rod 11 in use, and the at least one arm or tab 6, 7 is configured to deform so as to engage and bear against an inner wall W of the hole H when the retainer device 1 mounted on the anchor rod 11 is driven into the hole H. The invention also relates to a rock anchor system 10, comprising: at least one elongate anchor rod 11; a drill bit 12 configured for attachment to one end region 13 of the elongate anchor rod 11 for drilling the anchor rod 11 into rock strata R; and at least one retainer device 1 according to the invention described above for retaining or holding the anchor rod 11 in a hole H drilled in the rock strata R above horizontal. The invention also provides a method for installing a rock anchor.