Masonry Drill Bit Helix Transition for Flute Breakage Resistance
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Solution Overview
Problem
Masonry drill bits face high stress and vibration during long drilling operations in hard substrates, leading to flute breakage and reduced durability, especially in smaller diameter, longer length bits.
Innovation Solution
The drill bit design features a helical conveying portion with a changeover portion that alters flute pitch and web widths, distributing forces and mitigating vibrations, along with a gradual change in web width and pitch from the drilling head to the shank, enhancing stability and resistance to failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the drill bit is designed with a long flute portion for deep hole drilling, then the drilling depth capability is improved, but the flute portion becomes more susceptible to breakage due to prolonged exposure to high stress and vibrations
Solution Approach 1:
The patent applies local quality by varying the web width along the length of the flute portion. The web width is smaller near the drilling head to reduce weight and improve cutting performance, and gradually increases toward the shank to enhance structural strength and vibration resistance in the region most susceptible to breakage during deep hole drilling.
Solution Approach 2:
The patent implements dynamics by introducing a changeover portion that alters the helical geometry parameters (pitch and web width) at a specific location along the flute. This creates a dynamic transition in structural properties along the flute length, optimizing both cutting efficiency near the head and structural integrity near the shank for deep hole applications.
2Productivity
If the flute portion is made with smaller web width to reduce weight and improve material removal, then the drilling speed is improved, but the structural strength and vibration resistance of the flute portion deteriorates
Solution Approach 1:
The patent applies local quality by making the web width smaller in the forward portion of the flute (near the drilling head) where material removal is most active, thereby improving drilling speed and chip evacuation. The web width then gradually increases toward the shank to provide the structural strength needed to withstand vibrations and stresses, particularly in deep hole drilling operations.
3Duration of action of moving object
If the drill bit operates for extended periods to complete deep hole drilling, then the drilling depth is achieved, but the cumulative stress and vibration exposure increases the likelihood of flute breakage
Solution Approach 1:
The patent implements dynamics by creating a changeover portion that transitions the flute geometry from a lighter configuration (smaller web width, different pitch) to a stronger configuration (larger web width, modified pitch). This dynamic geometric transition allows the flute to withstand the cumulative stress and vibration exposure during extended drilling operations required for deep hole applications.
Solution Approach 2:
The patent applies beforehand cushioning by designing the changeover portion to gradually increase web width before the critical shank region. This progressive strengthening acts as a cushion against the cumulative effects of stress and vibration during long drilling operations, preventing sudden flute breakage while maintaining drilling efficiency throughout the extended operation duration.
Data Source
AI summary
A drill bit for drilling into masonry or rock includes a drilling head at its forward end, a clamping shank at its rearward end, and a helical conveying portion extending between the drilling head and the shank. The helical conveying portion includes at least two helically extending flutes separated by at least two helically extending webs. The helical conveying portion has a changeover portion, a pre-changeover portion between the drilling head and the changeover portion, and a post-changeover portion between the changeover portion and the shank. In the pre-changeover portion, the flutes have a pre-changeover pitch, the first web has a first pre-changeover web width α, and the second web has a second pre-changeover web width α′. In the post-changeover portion, the flutes have a post-changeover pitch, the first web has a first post-changeover web width β, and the second web has a second post-changeover web width β′. The post-changeover pitch is greater than the pre-changeover pitch, the first post-changeover web width β is less than the first pre-changeover web width α, and the second post-changeover web width β′ is greater than the second pre-changeover web width α′.