Tool Holder Through-Bore Locking for Thread-Safe Cutting Head Clamping
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Solution Overview
Problem
Existing rotary cutting tools face challenges in securely and efficiently attaching the cutting head to the tool holder, particularly in maintaining a firm clamping force without damaging the threads during interrupted drilling operations.
Innovation Solution
The design incorporates a tool holder with a through bore that allows a fastening member to engage both the head coupling pin's abutment surface and a through bore support surface, using a non-threaded engagement portion and internal threaded fixation, ensuring secure attachment and preventing thread damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a threaded fastening member is used to secure the cutting head to the tool holder, then the cutting head can be firmly attached, but the threads may be damaged during interrupted drilling operations
Solution Approach 1:
The fastening member is segmented into two distinct functional portions: a non-threaded engagement portion that contacts the cutting head and a threaded fixation portion that secures to the tool holder. This segmentation allows the non-threaded portion to bear the clamping load without transmitting stress to the threads, preventing thread damage during interrupted drilling while maintaining firm attachment.
Solution Approach 2:
The non-threaded engagement portion acts as an intermediary between the cutting head and the threaded fixation portion. It transfers the clamping force from the cutting head to the threaded portion, which then transfers it to the tool holder. This intermediary structure protects the threads from direct contact with the cutting head, preventing thread damage while maintaining secure attachment.
2Reliability
If the fastening member directly engages the cutting head with threads, then secure attachment is achieved, but thread damage occurs during operation
Solution Approach 1:
The fastening member is divided into a non-threaded engagement portion and a threaded fixation portion. The non-threaded portion directly engages the cutting head, providing secure attachment without involving threads. This eliminates the harmful effect of thread damage while maintaining reliable attachment security.
Solution Approach 2:
The threading function is extracted from the engagement interface with the cutting head and relocated to the fixation interface with the tool holder. The engagement portion becomes non-threaded, removing the source of thread damage from the cutting head interface while preserving attachment security through the non-threaded engagement design.
3Reliability
If a through bore is provided in the tool holder, then the fastening member can engage both surfaces for secure attachment, but the structure becomes more complex
Solution Approach 1:
The through bore in the tool holder serves multiple functions: it provides a passage for the fastening member, offers a support surface for the engagement portion, and enables the threaded fixation portion to secure the cutting head. This multi-functionality achieves firm attachment while minimizing structural complexity by using a single through-bore feature.
Data Source
AI summary
A cutting head has driven surfaces and includes a head coupling pin that protrudes rearwardly from a head rear surface. The head coupling pin includes a pin recess recessed in the pin peripheral surface. A tool holder, elongated along a holder longitudinal axis, has driving members and a holder coupling hole recessed in a holder base surface. A fastening member is disposed in a holder through bore that extends from the holder base surface to a holder peripheral surface. The holder through bore is located entirely on one side of a longitudinal plane containing the holder longitudinal axis. When a cutting tool which includes the cutting head and tool holder is in a fastened position, the head coupling pin is removably retained within the holder coupling hole upon engagement with the fastening member.