Quick Change Chuck Centering Shaft Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Chucks used for drill bits often experience slip and run-out issues due to the inaccuracy of hexagonal shanks and bores, leading to operational problems like out-of-true rotation and difficulty in drilling accurately, especially in metals, and are limited in accommodating various drill diameters.
Innovation Solution
A quick change chuck system with a centering shaft and drive shoulder portions of varying hexagonal sizes to accommodate different drill diameters, minimizing run-out and allowing for easy tool changes, including a drill bit adapter for securement and rotational energy transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hexagonal shanks and bores are used for drill bit mounting, then quick change capability is improved, but manufacturing precision deteriorates due to difficulty in maintaining straightness and dimensional accuracy
Solution Approach 1:
The drill bit shank is segmented into two distinct portions: a centering shaft portion with constant diameter for accurate alignment, and a drive shoulder portion with hexagonal cross-section for rotational drive. This segmentation allows each portion to optimize its function independently, resolving the contradiction between quick change capability and manufacturing precision.
Solution Approach 2:
The centering shaft portion acts as an intermediary element between the drill bit and the chuck bore. It provides a precise cylindrical interface that mediates the alignment function, while the hexagonal drive shoulder handles the rotational drive function, thereby separating the conflicting requirements of precision and quick change capability.
2Force
If hexagonal shanks are used for drill bits, then rotational drive capability is improved, but run-out increases due to play between the bore and shaft
Solution Approach 1:
The shank is divided into a centering shaft portion that eliminates radial play through precise cylindrical fit, and a drive shoulder portion that provides hexagonal rotational drive. This segmentation ensures that the centering function and drive function are performed by separate elements, preventing run-out while maintaining rotational drive capability.
3Device complexity
If a single hex chuck is used for all drill sizes, then device complexity is reduced, but adaptability deteriorates as larger diameter drills require heavier rotational forces
Solution Approach 1:
The chuck is designed with a universal bore that accepts the constant diameter centering shaft portion of all drill bits regardless of size. The drive shoulder portion varies in hexagonal cross-section to accommodate different drill sizes and rotational force requirements. This universal interface design allows a single chuck to adapt to multiple drill sizes while maintaining appropriate drive capability.
Data Source
AI summary
A tool arrangement and chuck apparatus for quick change of a range of tools; particularly, a quick change chuck adapted to engage various diameter drill bits, tools and tool holders. The tools are rotatable in a chuck or adaptor and have at one end a centering shaft portion having a constant diameter for multiple tool end diameters and shapes, a drive shoulder portion and a lock portion. The chucks have a tool centering arrangement for accommodating the constant diameter centering shaft. The chucks are also described as having tool bit release mechanism operable to disengage the tool from a retention mechanism when a force is applied inwards of the body of the chuck by the user to allow the tool bit to be removed longitudinally from the chuck but also arrange to allow the tool bit to be inserted longitudinally into the chuck without requiring any other user operation.