Modular Drill Shank With Offset Supporting Surfaces
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Solution Overview
Problem
Existing rotary cutting tools with interchangeable tips face challenges in securing the cutting tip effectively, particularly in absorbing lateral forces and ensuring reliable locking, especially with varying production tolerances and wear over multiple exchanges.
Innovation Solution
The design incorporates a shank with a locking geometry featuring an undercut and two axially offset supporting surfaces, which interact with corresponding surfaces on the cutting tip to absorb lateral forces and ensure secure locking, utilizing an interference fit and radial fingers for flexibility and ease of exchange, along with a centering pin for precise alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single supporting surface is provided in the region of the locking projection, then the cutting tip can be supported laterally, but the reliability is insufficient when cutting tips are exchanged and production tolerances occur
Solution Approach 1:
The single supporting surface is segmented into two axially offset supporting surfaces (first supporting surface and second supporting surface), each providing support at different axial positions. This segmentation distributes the support function across multiple locations, increasing reliability without excessive complexity
Solution Approach 2:
The supporting surfaces are arranged in the axial dimension rather than only radially, creating axial offset between support points. This dimensional arrangement ensures that even if one surface is affected by tolerances or wear, the other maintains reliable support
2Reliability
If the cutting tip is securely locked to the shank, then lateral forces are absorbed, but the cutting tip cannot be easily removed and replaced
Solution Approach 1:
The locking system transitions from a static interference fit to a dynamic bayonet-style locking mechanism that can be easily engaged and disengaged through rotational motion. The undercut geometry allows the locking projection to snap into place during insertion and can be released by reversing the rotation
Solution Approach 2:
The bayonet-style locking uses curved rotational paths and angled surfaces to achieve secure locking through simple rotational motion, making the locking and unlocking actions intuitive and easy to perform during tip exchange
3Ease of operation
If axial fingers are used to form supporting surfaces, then radial flexibility is achieved for easy insertion, but the fingers must be sufficiently elastic to bend radially outward
Solution Approach 1:
The finger geometry is optimized with specific dimensional parameters (length, thickness, width ratios) that enable the material to exhibit sufficient elastic deformation during insertion while maintaining structural integrity. The fingers are designed to bend radially outward during insertion and then spring back to provide stable support
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enhances the stability and reliability of the cutting tool by effectively absorbing lateral forces and ensuring secure locking, even with worn components, facilitating easy and reliable tip exchanges while preventing double fits and damage during locking.
Implementation Method 1
the fingers are easily bent elastically radially outward when the cutting tip is fastened
Implementation Method 2
a locking geometry having an undercut against the direction of rotation, into which undercut a locking projection of the cutting tip projects
Data Source
AI summary
A rotary cutting tool has a shank and an interchangeable cutting tip which can be coupled to the shank. The shank has a locking geometry having an undercut into which a locking projection of the cutting tip projects. Numerous lateral supporting surfaces and supporting counter-surfaces are provided for laterally fixing the cutting tip in the shank.