Parallel Tool-Changing Arm Mechanism for Drilling Machine
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Solution Overview
Problem
Existing automatic tool changers for drilling machines face inefficiencies due to insufficient overlap between the turning and axial movement of the tool-changing arm, leading to longer tool-changing times and suboptimal path following.
Innovation Solution
The automatic tool changer employs a parallel operation mechanism where the 180° turning and forward/backward movement of the tool-changing arm are executed simultaneously, with additional turning in the opposite direction during tool pullout and overshot movement during insertion, utilizing a cam mechanism driven by an electric motor to enhance speed and reduce deceleration time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the turning and axial movement of the tool-changing arm are mechanically worked together by a cam mechanism, then the tool-changing arm is operated quickly and smoothly, but the overlap between turning and axial reciprocation is insufficient when movement distance is short
Solution Approach 1:
The patent applies dynamics by making the tool-changing arm's movement path variable rather than fixed. The arm can dynamically adjust its trajectory to follow the shortest path between tool positions, and can vary its speed throughout the cycle. This allows the system to optimize the overlap between turning and axial reciprocation movements, reducing total tool-changing time while maintaining smooth operation through the cam mechanism.
Solution Approach 2:
The patent implements preliminary action by having the tool-changing arm start its turning motion before the axial reciprocation is complete, and vice versa. The turning operation starts in the midst of tool pullout, and tool inserting starts in the middle of the 180° turn. This overlapping of operations reduces idle time and accelerates the tool-changing cycle.
2Length of moving object
If the tool-changing arm follows the shortest path during movement, then the movement distance is minimized, but the acceleration and deceleration time near interference points increases
Solution Approach 1:
The patent applies the skipping principle by having the tool-changing arm rush through interference points at high speed rather than slowing down. The arm is designed to pass through tapered holes and other interference zones quickly, minimizing the time spent decelerating and accelerating near these points. This is achieved by optimizing the movement profile to maintain momentum through critical zones.
Solution Approach 2:
The patent resolves the contradiction by adding temporal dimension to the optimization. Instead of only minimizing spatial distance, the system optimizes the time-profile of movement. The arm can take slightly longer paths in space if they allow for higher speeds and better overlap of operations, thus reducing total time. The movement is optimized in the time-space domain rather than purely spatial domain.
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 configuration significantly reduces tool-changing time by increasing overlap and accelerating the tool-changing arm through interference points, allowing for continuous tool exchange without interruption and minimizing deceleration losses.
Implementation Method 1
the turning and axial movement of shafts of the tool-changing arm are viewed individually, it is hard to say that a sufficient amount of overlap is ensured in the case where a movement distance is short
Data Source
AI summary
Disclosed in an automatic tool changer in which the tool changing time can be shortened by increasing overlapping operations of the turning operation and the axial advancing/retracting operation of a replacement arm. An arm driver (32) is so constituted that the driver performs overlapping operations such that at least a part of the operation for turning a replacement arm (23) by 180° and the operation for advancing/retracting the replacement arm in the axial direction in order to insert or withdraw a tool (37) are performed simultaneously and in parallelism with each other. When the replacement arm (23) is advanced/retracted in the axial direction in order to insert or withdraw a tool, the replacement arm (23) is turned by a predetermined distance in a direction reverse to the direction (so called “normal direction”) for turning the arm by 180° in parallelism with the advancing/retracting operation, and thereafter, the replacement arm (23) is turned in the normal direction.