Tool Holding Structure With Fitting Member Preventing Slip-Out
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Solution Overview
Problem
Existing tool holding structures face challenges in preventing slip-out and relative rotation of cutting tools due to insufficient clamping force, particularly when exposed to excessive loads during cutting operations, and require complex threading or additional features on disposable cutting tools.
Innovation Solution
A tool holding structure featuring a fitting member aligned with an outer fitting portion on the cutting tool's shank and a chuck portion with a guide groove and inner fitting portion, including a rotation preventing face and slip-out preventing face, which effectively secures the tool by preventing rotation and slip-out through contact with these faces, and optionally utilizing a collet and urging mechanism for enhanced stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pin insertion hole is provided as an inner fitting portion to extend through the end face of the chuck portion, then the fitting member can be fitted from the outside to prevent slip-out and relative rotation, but the strength of the chuck portion is reduced and working becomes troublesome for forming threads
Solution Approach 1:
The invention extracts the threading operation from the chuck portion by providing a through-hole that allows the fitting member to pass through completely. The fitting member itself carries the threading features (male threads on the fitting member engaging with female threads in the through-hole), thereby eliminating the need to form threads in the chuck portion wall and preserving its structural integrity.
Solution Approach 2:
The fitting member acts as an intermediary component that carries the threading features and fitting functionality. Instead of forming threads directly in the chuck portion wall, the threading is transferred to the fitting member, which then mediates the connection between the chuck portion and the shank portion's outer fitting portion.
2Reliability
If female and male threads are formed in the chuck portion and fitting member respectively to prevent inadvertent detachment, then the fitting member is secured, but working is troublesome for forming the threads
Solution Approach 1:
The threading operation is extracted from the chuck portion and relocated to the fitting member. The through-hole configuration allows the fitting member to carry both the male threads (for engaging the shank portion) and the female threads (for engaging the chuck portion), simplifying the manufacturing process by eliminating thread formation in the chuck portion wall.
Solution Approach 2:
The fitting member is designed as a multi-functional component that simultaneously provides: (1) the threaded connection to the shank portion's outer fitting portion, (2) the threaded connection to the chuck portion's through-hole, and (3) the prevention of slip-out and relative rotation. This consolidates multiple functions into a single component, reducing manufacturing complexity.
3Ease of operation
If engaging protrusion and engaging groove are formed in the cutting tool to facilitate attachment and detachment, then the attachment process is simplified, but the number of production steps for producing the cutting tool is increased
Solution Approach 1:
Instead of forming engaging features directly on the disposable cutting tool shank portion, the invention inverts the approach by providing the fitting member with the engaging features (outer fitting portion with threads) that mate with corresponding features on the tool holder. This reverses which component carries the complex fitting features, allowing simpler cutting tools to be used while maintaining ease of attachment and detachment.
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
The structure reliably prevents coming-off and relative rotation of cutting tools, even under excessive loads, while simplifying the attachment process and reducing the number of production steps, and allows for easy replacement of wear-prone components.
Implementation Method 1
the chuck portion is heated to be expanded, into which the shank portion is inserted and then cooled together
Data Source
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AI summary
Provided is a tool holding structure capable of effectively preventing a cutting tool from coming off a chuck portion. An outer fitting portion (A) is formed in an outer face of a shank portion (2) of a cutting tool (T) and an inner fitting portion (B) is formed in an inner face of a chuck portion (12) of a tool holder. A fitting member (20) is provided to be fitted to the outer fitting portion (A) and the inner fitting portion (B) respectively. The fitting member (20) includes a protruding portion (22) which protrudes from an outer circumference of the shank portion (2) when fitted to the outer fitting portion (A). A guide groove (18) is formed for guiding the protruding portion (22) of the fitting member (20) from an open side of an inner space (13) to the inner fitting portion (B). The inner fitting portion (B) includes a rotation preventing face for preventing relative rotation between a holder body (10) and the cutting tool (T) in association with contact thereof with the protruding portion (22) and a slip-out preventing face for preventing slip-out of the cutting tool (T) in association with contact thereof with the protruding portion (22).