Lever Pin Tool Holder Clamping Leverage
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Solution Overview
Problem
Existing metal cutting tool holders for turning operations lack effective clamping leverage, leading to inadequate retention of cutting inserts with blind bores, which can result in premature wear and damage due to improper pressure distribution.
Innovation Solution
A tool holder design featuring a lever pin with a tapering head and a fastening member that applies lateral forces through a fulcrum-lever configuration, providing enhanced clamping leverage by forming a dovetail angle with the cutting insert, minimizing contact areas to prevent direct pressure on the cutting edge and ensuring secure fastening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional screw member and clamping member are used to fasten the cutting insert, then the structure is simple, but the clamping leverage is insufficient leading to inadequate retention of cutting inserts with blind bores
Solution Approach 1:
The fastening mechanism transitions from a static screw-clamp system to a dynamic lever-pin system that rotates about a fulcrum. The lever pin pivots between a first position (insert installation) and a second position (insert clamping), creating mechanical leverage through rotational motion about the fulcrum axis. This dynamic action amplifies the clamping force applied to the cutting insert.
Solution Approach 2:
The lever pin acts as an intermediary mechanical element between the fastening member and the cutting insert. It transfers and amplifies the clamping force through its lever arm configuration, with the fulcrum serving as the pivot point. The lever pin's geometry (including the tapering head and contact surfaces) mediates the force distribution to achieve secure retention without direct pressure on the cutting edge.
2Ease of operation
If direct pressure is applied to the cutting insert bore, then fastening is achieved, but the cutting edge may be damaged due to concentrated force
Solution Approach 1:
The lever pin features locally optimized contact surfaces: a first contact surface that engages the cutting insert bore without concentrating force on the cutting edge, and a second contact surface that interfaces with the fastening member. The tapering head geometry distributes the clamping force over a larger area of the insert bore, preventing stress concentration that could damage the cutting edge while maintaining effective fastening.
Solution Approach 2:
The solution moves from direct axial pressure application to a multi-dimensional force distribution system. The lever pin's rotational motion about the fulcrum creates force components in multiple directions, and the angled contact surfaces redirect forces along optimal paths that secure the insert without compromising the cutting edge integrity.
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 tool holder achieves improved clamping leverage and secure retention of cutting inserts, reducing the risk of premature wear and damage by distributing forces effectively, thereby enhancing the longevity and performance of cutting tools during machining operations.
Implementation Method 1
A tool holder design featuring a lever pin with a tapering head and a fastening member that applies lateral forces through a fulcrum-lever configuration, providing enhanced clamping leverage
Implementation Method 2
forming a dovetail angle with the cutting insert, minimizing contact areas to prevent direct pressure on the cutting edge
Data Source
Figure 1~2
Figure 3~4
Figure 5~7
AI summary
A tool holder (100) includes an insert pocket (102) having a support surface (110) with a pocket recess (116) occupied by a lever pin (120), and a fastening member (130). A head portion (122) of the lever pin (120) has a lever head rear contact surface (C), located above the support surface (110), for pressing against a bore (148) of a cutting insert (140) in the insert pocket (102). The fastening member (130) engages a threaded recess (118) which extends from the pocket recess (116) along a threaded recess axis (T). The fastening member (130) includes a guiding prong (134), located within a blind hole (126) in the front of the lever pin (120). A clamping contact surface (B) of the fastening member (130) is adjacent to a lever front contact surface (H) of the lever pin (120). A first longitudinal distance (hi), between the lever rear contact surface (C) and the lever front contact surface (H), is smaller than a second longitudinal distance (h2), between the lever front contact surface (H) and a lever lower rear contact surface (G).