Directional Drill Hammer Pullback Adapter
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Solution Overview
Problem
In horizontal directional drilling operations, removing a hammer from a borehole at a target point is challenging due to instability and high costs, especially in rocky conditions, as retrace the bore path is often not feasible due to cave-ins.
Innovation Solution
A pullback adapter system is introduced, comprising a drill bit with internal passages and a pullback adapter that securely attaches to the drill bit, allowing the hammer to be pulled back through the drill string, reducing the need for extensive excavation and enabling the installation of new pipes with minimal surface disruption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the hammer is removed from the borehole at the target point by traditional excavation methods, then the hammer can be retrieved, but extensive excavation is required which increases costs and causes surface disruption
Solution Approach 1:
The pullback adapter is inserted through the drill bit's internal passages and nested within the drill bit structure. The adapter's legs extend through passages in the drill bit body and connect within the internal cavity, creating a nested configuration where the adapter is housed within the drill bit's internal structure. This nesting allows the hammer to be pulled back through the drill string without excavation.
Solution Approach 2:
The pullback adapter serves as an intermediary component between the hammer and the drill string. It provides a connection interface that allows the drill string to grip and pull the hammer back through the borehole. The adapter mediates the force transmission from the drill string to the hammer, enabling retrieval without traditional excavation methods.
2Object-affected harmful factors
If the drill string is used to pull the hammer back through the borehole, then excavation is minimized, but the drill bit requires internal passages and an attachment mechanism
Solution Approach 1:
The drill bit is designed with multi-functionality by incorporating internal passages and an internal cavity that serve dual purposes: they allow drilling operations to proceed normally while also providing a pathway and space for the pullback adapter to be installed and function. The same drill bit structure enables both cutting/drilling and hammer retrieval functions.
Solution Approach 2:
The pullback adapter is divided into segmented components including multiple legs that extend through separate passages in the drill bit. This segmentation allows the adapter to be assembled by inserting individual legs through the drill bit's passages and connecting them within the internal cavity, simplifying the attachment process while maintaining structural integrity.
Data Source
AI summary
A pullback system to install or replace underground utilities that is used with a hammer used in horizontal directional drilling operations. The system comprises a drill bit attached to the hammer. The drill bit comprises a cutting face comprising a first and second passage. The system further comprises a pullback adapter comprising an attachment member, a first member, and a second member. The attachment member may be secured to the cutting face of the drill bit by inserting the first member of the pullback adapter through the first passage of the cutting face and inserting the second member of the pullback adapter through the second passage of the cutting face. The first member secures to the second member within an internal cavity of the drill bit to hold the attachment member for movement with the drill bit. A new pipe may be secured to a shackle on the pullback adapter. The drilling machine will then pull the hammer rearwardly through the borehole which in turn pulls the new pipe into the borehole.