Bottoming Tap and Chaser for Deep Blind Hole Threading
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Solution Overview
Problem
Existing taps and chasers face challenges in deep blind holes due to the need for multiple tools of varying lengths, misalignment, debris build-up, and increased risk of breakage, especially when using long tools in confined spaces.
Innovation Solution
A tap and chaser design with a cylindrical receiver and threading section connected by a shaft, allowing full insertion and alignment within the bore hole, featuring a central bore for extraction, and spiral flutes for efficient debris removal, along with a drive socket for standard ratchet drivers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If long tools are used to reach deep blind holes, then the tool can access the hole, but alignment between the tool and hole is lost increasing cross-threading risk
Solution Approach 1:
The tool is divided into a receiver portion that remains outside the hole and a threading section that enters the hole. The receiver has a reduced diameter to fit within the hole while the threading section performs the cutting operation, separating the alignment function from the cutting function.
Solution Approach 2:
A pilot or alignment feature is introduced as an intermediary element that guides the threading section into proper alignment with the hole before cutting begins. This pilot acts as a mediator between the tool and the workpiece to ensure coaxial alignment.
2Adaptability or versatility
If multiple taps and chasers of different lengths are maintained for deep blind holes, then various depths can be accommodated, but tool inventory complexity and cost increase
Solution Approach 1:
The tool incorporates an adjustable extension mechanism that allows the effective length of the threading section to be changed without replacing the entire tool. This dynamic adjustment capability enables a single tool to accommodate multiple hole depths.
Solution Approach 2:
The receiver is designed with a universal interface that can accept different threading sections or extensions, allowing one base tool to perform multiple functions at different depths. This multi-functionality eliminates the need for multiple specialized tools.
3Length of moving object
If long tools are used in deep blind holes, then the hole can be tapped, but clearance distance requirements severely limit usable locations
Solution Approach 1:
By segmenting the tool into a compact receiver and a threading section, the overall tool length is reduced while maintaining the ability to reach deep holes. The receiver portion fits within the hole opening, eliminating the need for large clearance distances.
Solution Approach 2:
The tool design transitions from a long axial configuration to a compact configuration where the receiver fits radially within the hole opening. This dimensional change allows access to confined spaces without requiring extensive linear clearance.
4Ease of operation
If standard t-handle drivers are used with taps, then the tap can be driven, but the driver prevents the tap from being used in deep blind holes
Solution Approach 1:
The driving interface is extracted from the traditional t-handle configuration and relocated to the receiver portion of the tool. This allows the driving mechanism to be positioned outside the hole while the threading section operates inside, combining ease of operation with deep hole capability.
Data Source
AI summary
A tap and chaser are provided each having a cylindrical tool receiver connected to a threading section by a shaft. The receiver and shaft are of diameters sufficiently small to enter the bore hole and distribute any off axis load onto a number of internal threads of the bore hole to dissipate loading. A central bore is provided for broken tool extraction. The threaded section includes a group of longitudinal flutes. Each of the lands of the threaded section includes a novel cutting face, tooth angle and rake angle to advantageously allow for threading deep blind holes.