Drill Shank Bit Alignment via Guide Pin Mechanism
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Solution Overview
Problem
Conventional drilling tools for concrete often experience center misalignment between the shank and bit, leading to reduced drilling efficiency and increased hole diameter, which degrades the strength of anchor attachments due to reliance on screw connections that require high processing accuracy and abutting surface precision.
Innovation Solution
The drilling tool incorporates a guide part with fitting and fitted portions near screw connections to facilitate center alignment, eliminating the need for precise screw accuracy and abutting surface perpendicularity, and includes an inclined plane to discharge concrete cuttings, ensuring accurate alignment and preventing excessive screw rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If screw connections are used to connect shank and bit, then the bit can be replaced without replacing the shank, but center misalignment occurs between shank and bit
Solution Approach 1:
A guide part is introduced as an intermediary component between the shank and bit. This guide part includes a guide hole through which a guide pin passes, creating a mechanical constraint that ensures accurate center alignment. The guide part acts as a mediator that translates the screw connection's ease of assembly into precise positional alignment, resolving the contradiction between replaceability and alignment accuracy.
Solution Approach 2:
The solution adds a dimensional constraint by introducing a guide pin that moves through a guide hole in the axial direction. This creates a new degree of freedom control mechanism that constrains the radial position of the bit relative to the shank, thereby achieving center alignment without compromising the screw connection's replaceability feature.
2Manufacturing precision
If high processing accuracy of screw portions and abutting surfaces is required for center alignment, then alignment accuracy improves, but manufacturing complexity and cost increase
Solution Approach 1:
The guide part serves as a mediator that takes over the alignment function from the screw portions and abutting surfaces. By introducing this intermediate alignment mechanism, the patent eliminates the need for high processing accuracy in the original screw connection components, thereby reducing manufacturing complexity while maintaining alignment accuracy.
Solution Approach 2:
The patent replaces the reliance on precision-machined screw portions and abutting surfaces with a simpler mechanical constraint system consisting of a guide pin and guide hole. This substitution transforms the alignment mechanism from one dependent on high manufacturing precision to one based on geometric constraint, reducing device complexity.
3Ease of operation
If gap exists between male and female screw portions for tightening and loosening, then screw connection functionality is enabled, but center misalignment occurs
Solution Approach 1:
The guide part acts as an intermediary that decouples the gap necessary for screw operation from the alignment function. The guide pin-constraint mechanism maintains center alignment independently of the screw gap, allowing the screw portions to have sufficient clearance for tightening and loosening without compromising alignment accuracy.
Data Source
AI summary
In a drilling tool including: a shank located at a tip side of a tool main body; and a bit located at a tip side of the shank, the shank and the bit (connection body) are connected to each other via screws, and a guide part for center alignment for aligning the centers of the shank and the bit is formed in the vicinity of screw portions of the shank and the bit.