Lathe Chuck Keyway Structure for Accurate Jaw Support
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Solution Overview
Problem
The existing chuck designs for lathes suffer from distortions and deformations in master jaws and body due to uneven force distribution, leading to inaccurate workpiece support.
Innovation Solution
The chuck design features a body with keyways of inverted T-shape and master jaws with wider sliding surfaces that provide increased contact area for force distribution, along with wedges of greater width to stabilize the workpiece and reduce distortions, and a lubricant supply mechanism for smooth operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the sliding surfaces are ground to have high dimensional accuracy and smoothness, then the support accuracy is improved, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent changes the geometric parameters of the keyway cross-section from a conventional design to an inverted T-shape with specific dimensional relationships. The width of the keyway at the sliding surface contact region is made larger than the width of the master jaw, creating intentional gaps. This parameter change allows the sliding surfaces to be ground with high precision while the gap structure compensates for potential deformation, maintaining accuracy without requiring overly complex processing setups.
2Device complexity
If the contact area between keyways and sliding surfaces is small, then the device complexity is reduced, but distortions and deformations in master jaws increase
Solution Approach 1:
The patent applies local quality by creating different contact conditions in different regions. The keyway has a larger width at the sliding surface contact region compared to other sections, providing increased contact area and better force distribution where needed. This local enhancement of contact quality reduces distortions and deformations in the master jaws without requiring a complete redesign of the entire structure, thus avoiding excessive complexity.
3Device complexity
If the wedge width is reduced to fit in the keyway, then the device complexity is reduced, but the force distribution becomes uneven causing body distortions
Solution Approach 1:
The patent employs asymmetry in the keyway cross-sectional design. The keyway has different widths at different locations: a larger width at the sliding surface contact region and a smaller width in other sections. This asymmetric geometry allows the wedge to be positioned optimally, providing sufficient contact area for even force distribution while maintaining a compact overall structure. The asymmetric design resolves the contradiction between wedge size and force distribution uniformity.
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 accuracy of workpiece support by minimizing distortions and deformations in the chuck components, ensuring precise and reliable operation.
Implementation Method 1
Due to the rearward draw of the plunger 103 and a wedge effect, the wedge 106 receives a radially inward force as indicated by the arrow N.
Data Source
AI summary
A chuck includes a plurality of master jaws 20 that slide in the radial direction in the front surface of a body 10 in conjunction with slide of a plunger 40. The body 10 has a housing chamber 11 communicating with a plurality of keyways 13. The plunger 40 is fitted in the housing chamber 11. Each of the master jaws 20 includes a narrower part 21 and a wider part 22 fitted into an associated one of the keyways 13, and a wedge 23 connected to the plunger 40. The wider part 22 has a flat wider sliding surface 22b radially outside the wedge 23. Each of the keyways 13 has a wider slid surface 14.