Pullback Adaptor Mounting Arrangement for HDD Drill Bits
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Solution Overview
Problem
Existing mounting arrangements for pullback adaptors and drill bits in horizontal directional drilling (HDD) machines often result in misalignment of the swivel with the longitudinal axis, causing the product being installed to rotate undesirably during the pulling process, and require a variety of parts for different drill bit configurations, leading to inconsistent operation.
Innovation Solution
A universal pullback adaptor design that includes a protrusion with a threaded aperture and an annular planar mount surface, which engages the drill bit's adaptor mount surface, ensuring the swivel remains aligned with the boring tool's longitudinal axis and can be mounted to various drill bits, preventing excessive rotation and reducing the need for multiple parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a traditional mounting arrangement with a shackle and bolt is used to connect the pullback adaptor to the drill bit, then the assembly can be constructed with simple components, but the swivel becomes misaligned with the longitudinal axis of the boring tool, causing the installed product to rotate undesirably during pulling
Solution Approach 1:
A mounting arrangement is introduced as an intermediary component between the drill bit and pullback adaptor. This mounting arrangement includes a mounting surface that contacts the drill bit and a connection surface that connects to the pullback adaptor, thereby mediating the connection to achieve proper alignment while maintaining structural simplicity
Solution Approach 2:
The mounting arrangement extends in a direction generally perpendicular to the longitudinal axis of the boring tool, creating a dimensional offset that allows the swivel to be positioned in proper alignment with the longitudinal axis while the mounting structure extends laterally from the drill bit
2Adaptability or versatility
If different parts are used for different drill bit configurations, then each specific drill bit type can be accommodated, but the number of parts increases and operation becomes inconsistent
Solution Approach 1:
The mounting arrangement is designed with a universal mounting surface configuration that can accommodate various drill bit types including straight shaft bits and bent bits. The same mounting arrangement design can be used across different drill bit configurations, eliminating the need for multiple specialized parts while maintaining adaptability
Solution Approach 2:
The mounting surface of the mounting arrangement is designed with homogeneous geometric features (such as counterbores and flat surfaces) that can interface with different drill bit configurations in a consistent manner, allowing the same mounting arrangement to work with various drill bits without requiring different part designs
3Productivity
If the swivel is allowed to rotate freely during product installation, then the drill bit can rotate while pulling the product, but the product itself rotates undesirably which can cause installation problems
Solution Approach 1:
The mounting arrangement provides a fixed connection between the drill bit and pullback adaptor at the mounting interface, while allowing rotation at the drill bit level. This localized differentiation enables the drill bit to rotate for productivity while the swivel and installed product remain stationary and properly aligned
Data Source
AI summary
A combination of a pullback adaptor and a drill bit includes a pullback adaptor having a first end, a second end, a body extending between the first end and the second end, and a protrusion extending from the body adjacent the second end. The protrusion has a threaded aperture defining an adaptor mounting axis, and the protrusion defines an annular planar mount surface generally perpendicular to the adapter mounting axis. A drill bit has a body with a steering surface, an aperture extending through the body at the steering surface, and an adaptor mount surface adjacent the aperture. The pullback adaptor is mounted to the drill bit with a fastener that extends through the aperture in the drill bit and into the threaded aperture of the pullback adaptor such that the annular planar mount surface of the protrusion engages the mount surface of the drill bit.