Double-Wedge Rock Bolt for Greater Expansion Anchoring
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Solution Overview
Problem
Existing rock bolts often fail to achieve proper anchoring to formations due to limited expansion range, leading to inadequate reinforcement.
Innovation Solution
A rock bolt design featuring a central rod, tubular outer body, and an expansion mechanism with wedges that allow for controlled radial expansion, utilizing a drive wedge and intermediate wedge to ensure proper anchoring by expanding the outer body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-stage expansion mechanism is used, then the device complexity is reduced, but the expansion range is limited and proper anchoring cannot be achieved
Solution Approach 1:
The expansion mechanism is divided into two independent wedge stages: a first wedge means (drive wedge) that expands an intermediate wedge, and a second wedge means (expansion wedge) that expands the outer body. This segmentation allows each stage to contribute to the total expansion range, enabling reliable anchoring while maintaining manageable structural complexity through modular design.
Solution Approach 2:
The intermediate wedge is nested within the outer body, and the drive wedge is nested within the intermediate wedge. This nested configuration allows the expansion forces to be transmitted sequentially from the inner wedge to the outer body, maximizing the expansion range without requiring a overly complex external mechanism structure.
2Ease of manufacture
If the wedge means are made simple, then the ease of manufacture is improved, but the control over radial expansion is reduced
Solution Approach 1:
The wedge means are designed with inclined surfaces that convert axial movement of the central rod into radial expansion of the outer body. The geometry of the wedge surfaces provides mechanical advantage and controlled expansion ratios, allowing precise control over the expansion process while maintaining relatively simple manufacturing requirements for the wedge components themselves.
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
Enhances the expansion range and control of the rock bolt's anchoring, ensuring better engagement with the formation for effective reinforcement.
Implementation Method 1
The drive wedge and the intermediate wedge are configured such that the drive wedge is able to radially expand the intermediate wedge upon movement of the drive wedge in the first direction towards a trailing portion of the rock bolt
Implementation Method 2
The first wedge means and the second wedge means are configured such that the first wedge means is able to force the second wedge means radially outwards about the longitudinal axis of the rock bolt upon movement of the first wedge means in a first direction towards a trailing portion of the rock bolt rod to thereby radially expand the outer body
Data Source
Figure 1
Figure 2a~2b
Figure 3a~3b
AI summary
A rock bolt (1) comprising a wedge-based expansion mechanism. The expansion mechanism comprises drive wedge (8) acting to expand an intermediate wedge (9) upon tensioning of the rock bolt (1), wherein the intermediate wedge (9) acts to expand a wedge means attached to an outer tube (4) of the rock bolt (1). The use of the intermediate wedge (9) enables greater expansion of the rock bolt (1).