Slanted Screw Fastening for Cutting Insert Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing cutting tools face issues with screws becoming unfastened due to perpendicular fastening, which fails to adequately support cutting forces, and are further compromised by heavier vibrations, leading to instability and potential unfastening of cutting inserts.
Innovation Solution
A cutting tool design featuring a slanted threaded hole in the tool body with varying contact angles around the screw head, providing increased unclamping force and preventing screw unfastening during vibrations, while maintaining stability and preventing screw jamming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a screw is fastened perpendicularly to the cutting insert seating surface, then the screw structure is simple, but the screw fails to sufficiently support the reaction force corresponding to cutting force and becomes unfastened
Solution Approach 1:
The screw fastening structure transitions from a perpendicular (symmetric) configuration to a slanted (asymmetric) configuration. The screw axis is inclined at an angle α (10°-30°) relative to the perpendicular direction, creating asymmetric force distribution that generates both clamping force (perpendicular to seating surface) and retaining force (parallel to seating surface), thereby simultaneously improving securing reliability while maintaining structural simplicity
Solution Approach 2:
The fastening angle parameter is changed from 90° (perpendicular) to a slanted angle (60°-120° relative to seating surface). This parameter modification transforms the force vector components, enabling the single screw to provide both perpendicular clamping force and horizontal retaining force, resolving the contradiction between simple structure and reliable securing
2Reliability
If a screw is fastened slantingly to provide both perpendicular and horizontal fastening forces, then the cutting insert can be more stably secured, but the screw cannot withstand heavier vibrations and becomes unfastened
Solution Approach 1:
The screw head contact geometry is modified to engage with the mounting hole wall surface at multiple dimensional levels. The contact occurs at both upper and lower portions of the mounting hole, creating a multi-dimensional constraint system that prevents screw displacement in multiple directions, thereby enhancing vibration resistance while maintaining the slanted fastening configuration
Solution Approach 2:
The screw head contact area is segmented into multiple discrete contact portions (upper contact portion and lower contact portion) along the longitudinal axis of the mounting hole. This segmentation distributes the vibration loads across multiple contact points, preventing concentrated stress and reducing the likelihood of screw unfastening under heavy vibration conditions
3Device complexity
If the screw head contacts the mounting hole wall surface at a single level, then the structure is simple, but the unclamping force is insufficient and the screw becomes unfastened under vibration
Solution Approach 1:
The contact geometry transitions from a single-level (2D) contact to a multi-level (3D) contact arrangement. The screw head contacts the mounting hole wall surface at both upper and lower portions along the longitudinal axis, creating a three-dimensional constraint system that significantly increases the unclamping force and prevents screw unfastening under vibration while maintaining reasonable structural complexity
Data Source
Figure 1~2
Figure 3~4
Figure 5~7
AI summary
The present invention provides a cutting insert and a cutting tool used with the same. A tool body includes at least one seating surface and a threaded hole extending as slanted with respect to the seating surface. At least one cutting insert having a mounting hole passing therethrough is removably secured on the seating surface. A screw passes through the mounting hole and is fastened to the threaded hole, thereby removably securing the cutting insert to the tool body. A wall surface of the mounting hole contacts a head of the screw about at least one first contact portion and at least one second contact portion. The first contact portion is formed at a level different from that of the second contact portion along a longitudinal axis of the mounting hole. Contact angles at the first contact portions and the second contact portions are different from each other.