Four-Sided Gripper Assembly for Stable CNC Workpiece Holding
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Solution Overview
Problem
Existing workpiece fastening methods in CNC machines only grip from two sides, leading to instability and risk of crushing or detachment during machining, and require higher pressure forces.
Innovation Solution
A gripper assembly comprising a plate, drive elements, a synchronous guide, and grippers that allow simultaneous movement and gripping of the workpiece from all four sides with equal force, ensuring secure holding and easy release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If workpiece is gripped from only two sides using conventional vices, then the device complexity is low, but the workpiece stability is insufficient and risk of detachment increases
Solution Approach 1:
The gripper assembly is divided into four independent gripper units, each capable of gripping the workpiece from a different side. Each gripper can be independently actuated or moved in a coordinated manner, allowing the system to provide stable holding from multiple directions simultaneously, thus resolving the contradiction between simplicity and stability.
Solution Approach 2:
The invention transitions from two-sided gripping (conventional vice) to four-sided gripping by adding grippers in additional spatial dimensions. This dimensional expansion allows the workpiece to be constrained from all sides, significantly improving stability and preventing detachment while maintaining a relatively simple overall structure.
2Strength
If workpiece is gripped from only two sides, then the device complexity is low, but the holding force required increases creating crushing risk
Solution Approach 1:
The total holding force is segmented and distributed across four separate grippers instead of concentrating it on two. Each gripper applies a portion of the total force, which reduces the pressure intensity on any single point of the workpiece while maintaining the overall holding strength, thereby preventing crushing.
Solution Approach 2:
Each gripper is designed to apply force locally at its specific gripping point, allowing for optimized force distribution across different locations of the workpiece. This localized force application ensures that no single area experiences excessive pressure that could lead to crushing, while the cumulative effect provides sufficient holding strength.
3Reliability
If gripping elements on all four sides move simultaneously, then the workpiece stability is improved, but the synchronization control complexity increases
Solution Approach 1:
The synchronous guide mechanism ensures that all four grippers move along equipotential paths, maintaining equal positioning relative to the workpiece at all times. This geometric constraint automatically synchronizes the movement of all grippers without requiring complex independent control systems for each one.
Solution Approach 2:
A synchronous guide acts as an intermediary mechanism that coordinates the movement of all four grippers. This intermediate component translates a single actuation input into synchronized motion of multiple grippers, simplifying the control architecture while ensuring reliable simultaneous movement.
4Manufacturing precision
If conventional two-sided gripping is used, then the ease of operation is high, but the machining precision may be compromised due to workpiece movement
Solution Approach 1:
By adding grippers in additional spatial dimensions (from two sides to four sides), the system constrains the workpiece more comprehensively in all directions. This multi-dimensional constraint prevents workpiece movement and shifting during machining, ensuring high positioning accuracy while maintaining operational simplicity through the unified gripper assembly design.
Data Source
AI summary
Disclosed is a gripper assembly used in milling or CNC machines with one or more than one axes, adapted to grip the workpiece from two or more directions at the same time and with the same force.