Removable Safety Anchor Sleeve for Corroded Rock Bolt Replacement
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Solution Overview
Problem
Existing low-cost wedge anchors are difficult to remove after installation and prone to corrosion, especially in outdoor environments, necessitating replacement without damaging the rock face.
Innovation Solution
A safety anchor design featuring a hanger member, threaded member, and hollow sleeve member, allowing for easy removal by applying an impact force to expel the wedge and pulling out the sleeve and hanger from the drilled hole, even in corroded conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a low-cost concrete wedge anchor is used, then cost is reduced, but the anchor becomes difficult to remove after installation
Solution Approach 1:
The anchor system is divided into separable components: the expansion clip, the threaded member, and the hanger are distinct parts that can be independently removed. The expansion clip can be detached from the threaded member by removing the nut, allowing the clip to be pulled out of the hole separately from the threaded member and hanger assembly.
Solution Approach 2:
The expansion clip is extracted from the threaded member through a two-stage removal process. First, the nut is removed to release the expansion force, allowing the clip to be partially extracted. Second, the hanger is removed to fully extract the clip from the hole, separating the expansion mechanism from the anchoring structure.
2Strength
If the expansion clip is expanded to secure the anchor, then anchoring strength is improved, but the anchor cannot be removed due to permanent expansion
Solution Approach 1:
The expansion clip transitions from a static permanently expanded state to a dynamic reversible state. The clip can be expanded by tightening the nut to achieve strong anchoring, and then collapsed by loosening and removing the nut, enabling the clip to be contracted and removed from the hole.
Solution Approach 2:
The nut is removed in advance of attempting to pull the anchor out, preparing the expansion clip for removal by releasing the expansion force beforehand. This preliminary action of removing the nut prevents the expansion force from blocking the removal of the anchor components.
3Reliability
If the anchor is left in place for extended use, then reliability is improved, but corrosion degrades the removal capability over time
Solution Approach 1:
The anchor system is segmented into removable components that can be taken out and replaced individually. The expansion clip, threaded member, and hanger are separate parts that can be removed as a group or individually, allowing corroded components to be replaced without affecting the drilled hole or surrounding structure.
Solution Approach 2:
Corroded anchor components are discarded and replaced with new ones. The expansion clip and threaded member can be removed from the hole and replaced, allowing maintenance of the anchoring system without drilling new holes. The hanger can also be replaced if corroded, recovering the functional capability of the anchor system.
4Ease of repair
If new holes are drilled to replace corroded anchors, then replacement is achieved, but the rock face is damaged
Solution Approach 1:
The anchor components are prepared for removal in advance by loosening the nut and detaching the expansion clip from the threaded member before attempting extraction. This preliminary preparation prevents damage to the rock face during removal, as the components can be pulled out through the existing hole without requiring forceful extraction that might damage surrounding rock.
Solution Approach 2:
The anchor components are extracted through the existing drilled hole without creating new holes or damaging the rock face. The expansion clip is pulled out first, followed by the threaded member and hanger, all through the original hole, preserving the rock surface for aesthetic and structural reasons.
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 easy and cost-effective replacement of anchors without drilling new holes, preserving the rock face and addressing corrosion issues.
Implementation Method 1
the tail end of the threaded member has a wedge portion adapted to expand the tail end of the sleeve member as a consequence of tightening the nut
Data Source
AI summary
A safety anchor for installing in a hole drilled into a structure, the anchor having a hanger member, a threaded member, and a hollow sleeve member, the sleeve member having a lip portion adapted to stand outside the drilled hole to facilitate grasping the sleeve portion and removing it from the hole after the anchor has been installed in the drilled hole, and the hanger member having a recess adapted to provide a volume of relief above the surface of the structure for receiving the lip member.