Drilling Assembly with Recoverable Cutters for Annular Cavities
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Solution Overview
Problem
Existing methods for drilling annular cavities for pile foundations and retaining walls are inefficient due to high energy consumption and the inability to recover cutting members, leading to excessive costs from the need for separate cutting tools for each cavity.
Innovation Solution
A drilling assembly with moveable cutting members that can be switched between a cutting and a retrieval condition, allowing the first body member and cutting members to be reused, combined with a mechanism for connecting sheet piles and delivering bonding material to form stable anchors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate cutting members are used for each annular cavity, then the cutting function is reliable, but the cost increases excessively
Solution Approach 1:
The cutting members are designed to be recoverable after use. The inner body member with attached cutting members is removed from the annular cavity after drilling, allowing the cutting members to be recovered and reused for subsequent drilling operations, eliminating the need to discard them with each cavity
Solution Approach 2:
The cutting members are designed to perform multiple drilling operations rather than being single-use. The same cutting members can be reused across multiple annular cavities, making the cutting tool universal and reducing overall project costs
2Ease of manufacture
If cylindrical cavities are formed by removing large volume of material, then the cavity formation is simple, but excessive energy is consumed
Solution Approach 1:
The cavity formation process is segmented into two stages: first forming a smaller pilot cylindrical cavity, then expanding it to the final annular cavity dimensions. This segmentation allows more efficient material removal by focusing cutting effort on the annular region rather than removing a full cylindrical volume
Solution Approach 2:
A pilot cavity is formed first before the final annular cavity is created. This preliminary action prepares the ground by removing the central material, making the subsequent annular cavity formation more energy-efficient as less resistance is encountered during the expansion phase
3Loss of substance
If the first body member and cutting members are removed after drilling, then the components can be reused, but the mechanism complexity increases
Solution Approach 1:
The inner body member with cutting members is nested within or alongside the outer body member during the drilling process. This nesting arrangement allows for a compact design where the removable components are integrated into the overall structure, reducing the apparent complexity while maintaining reusability
Solution Approach 2:
The cutting members are designed with movable or adjustable characteristics, allowing them to be positioned for cutting and then retracted or removed after drilling. This dynamic design enables the cutting members to transition between working and storage positions, facilitating reuse without requiring completely separate mechanisms
Data Source
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AI summary
A drilling assembly (2) for forming an annular cavity in a substrate is disclosed. The drilling assembly comprises an annular inner pile (6) including a first annular part (10), an annular outer pile (4) including a second annular part (8) and cutters (16) mounted to an end of the inner pile. The first annular part is located inside the second annular part, and the cutters are moveable relative to the inner pile between a first condition, in which rotation in a first direction of the inner pile causes the cutters to form an annular cavity in the substrate, and a second condition, in which the inner pile and the cutters can be removed from the cavity while leaving the outer pile in the cavity.