Rock Anchor Pressure Indicator for Hydraulic Inflation Control
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Solution Overview
Problem
Existing rock anchors lack a reliable method to indicate when the predetermined installation pressure is reached during hydraulic inflation, which is crucial for forming a stable frictional bond with the rock, potentially leading to incomplete or unstable anchor fixation.
Innovation Solution
Incorporating a pressure indicator mechanism with a displaceable body and frangible holding means on the end cap, which visually indicates when the installation pressure is achieved, ensuring the anchor tube is properly inflated and secured.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pressure indicator mechanism is added to indicate when installation pressure is reached, then the reliability of pressure control is improved, but the device complexity increases
Solution Approach 1:
The patent employs visual indicators that change position or appearance based on pressure levels. The indicator formation moves to different positions relative to reference markings as pressure increases, providing clear visual feedback without complex electronics. This resolves the contradiction by achieving reliable pressure indication through simple optical changes rather than complex sensing systems.
Solution Approach 2:
The pressure indicator mechanism is self-actuating through the pressure itself. The indicator formation is displaced by the liquid pressure directly, without requiring external power sources or complex actuation systems. The system uses the pressure being measured to drive the indication, eliminating the need for separate sensing and signaling systems.
2Strength
If the anchor tube is hydraulically inflated to achieve secure bonding, then the strength of the anchor increases, but the difficulty of detecting and measuring the installation pressure worsens
Solution Approach 1:
The patent introduces an intermediary mechanical linkage between the pressure source and the indicator. The indicator formation acts as a mediator that translates internal liquid pressure into external visual displacement. This intermediary mechanism makes the invisible pressure measurable and visible through simple positional changes relative to reference markings.
Solution Approach 2:
The patent replaces complex electronic pressure sensing systems with a purely mechanical indication system. The indicator formation is directly displaced by hydraulic pressure through mechanical means, converting pressure measurement into a simple mechanical position change that can be visually detected without electronic instruments.
3Reliability
If the body is held in the first position against pressure, then the reliability of pressure threshold detection is improved, but the device complexity increases due to holding means
Solution Approach 1:
The patent uses parameter changes in the holding means to achieve reliable threshold detection. The holding means is designed to yield at a specific pressure threshold, transforming the indicator from a continuously displaced element to one that changes position discontinuously at the target pressure. This parameter-based switching provides reliable threshold detection without complex control systems.
Solution Approach 2:
The holding means is pre-configured to yield at the desired pressure threshold during manufacturing. This preliminary setup ensures that the indicator will automatically switch positions at the correct pressure without requiring active control or adjustment during installation. The threshold detection is built-in and self-adjusting.
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 pressure indicator ensures that the anchor tube is inflated to the necessary pressure, providing a clear visual signal for terminating water injection and ensuring a secure frictional bond with the rock, enhancing the stability and reliability of the anchor fixation.
Implementation Method 1
a liquid substance being pressure fed into the anchor tube under a predetermined installation pressure, the tube is hydraulically inflated
Implementation Method 2
constrained in the bore, provides a frictional bond with the rock
Implementation Method 3
the body being displaceable, under liquid pressure against the contact surface, into a second position thereof
Data Source
AI summary
The invention relates to a rock anchor including an elongate, hydraulically inflatable anchor tube made of a ductile material and defining a closed leading end, a trailing end, and a tube cavity extending between the ends. The rock anchor of the invention includes an end cap on a trailing end of the tube, defining a feed aperture in communication with the tube cavity for pressure feeding a liquid substance into the tube cavity for inflating the tube. The end cap includes pressure indicator means configured for indicating when, as a result of pressure feeding of a liquid substance into the tube cavity, a predetermined installation pressure is reached in the tube cavity. The pressure indicator means typically includes a pressure indicator formation displaceable under pressure in the tube cavity, with such displacement being visible from the outside of the end cap.