Fluid Gripper Force Equalization for Thin-Wall Workpiece Holding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
There is a need for gripping apparatuses and methods that can accommodate workpieces with various shapes, particularly those with thin or porous wall structures, and maintain their working orientation during manufacturing or processing operations.
Innovation Solution
A fluid-operated gripping apparatus with equally spaced actuators around the workpiece perimeter, each actuator comprising an actuator rod coupled with a moveable piston within a cylinder, and configured to be coupled to a single pressurized fluid source. The apparatus uses a fluid circuit to equalize force across the actuators, ensuring the workpiece is held in a working orientation without over-constraining it.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If multiple actuators are used to grip the workpiece, then gripping force is improved, but the risk of over-constraining the workpiece increases
Solution Approach 1:
Each actuator is equipped with an end effector that contacts the workpiece at exactly two points rather than a single point or large surface area. This localized two-point contact configuration allows the actuators to apply gripping force while avoiding over-constraint of the workpiece, resolving the contradiction between providing sufficient gripping force and avoiding excessive constraints
Solution Approach 2:
The end effectors are pivotally coupled with the actuator rods, allowing them to dynamically adjust their contact points and orientation. This dynamic capability enables the system to accommodate workpiece orientation variations and maintain effective gripping without over-constraining the workpiece structure
2Device complexity
If actuators are coupled to a single pressurized fluid source, then system simplicity is improved, but control precision over individual actuators deteriorates
Solution Approach 1:
All actuators are coupled to the same pressurized fluid source, creating an equipotential system where fluid pressure is equalized across all actuators. This passive pressure equalization mechanism ensures synchronized actuator operation and maintains workpiece orientation without requiring complex active control systems, resolving the contradiction between system simplicity and control precision
3Stability of the object's composition
If end effectors contact the workpiece at multiple points, then gripping stability is improved, but the risk of over-constraining the workpiece increases
Solution Approach 1:
Each end effector is specifically designed to contact the workpiece at exactly two points, creating a stable gripping configuration that prevents workpiece rotation while avoiding over-constraint. This two-point contact geometry provides optimal stability without excessive constraints on the workpiece
Solution Approach 2:
The end effectors are configured with asymmetric two-point contact geometry relative to the actuator rod axis, which provides stable gripping while allowing the workpiece to maintain its natural orientation. The asymmetric contact points create stabilizing moments without over-constraining the workpiece structure
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 apparatus effectively grips and holds workpieces with curved sidewalls in a working orientation, allowing for precise manipulation and processing without damaging the workpiece, and can accommodate workpieces of various sizes without adjustment.
Implementation Method 1
supply pressurized fluid to the extend chamber of each actuator during a closing stroke of the gripping apparatus
Implementation Method 2
maintain a same fluid pressure within the extend chamber of each actuator while the workpiece is held by the gripping apparatus
Implementation Method 3
inhibit backflow of pressurized fluid from the extend chamber of each actuator toward a pressurized fluid source
Implementation Method 4
release pressurized fluid from the extend chamber of each actuator during an opening stroke of the gripping apparatus
Implementation Method 5
supply pressurized fluid to the retract chamber of each actuator during the opening stroke of the gripping apparatus
Data Source
AI summary
A fluid-operated gripping apparatus for holding a workpiece having a curved sidewall in a working orientation, and associated methods for gripping and holding a workpiece, are provided. Three fluid-operated actuators, each including an actuator rod and a moveable piston arranged within a cylinder, are equally spaced around a perimeter of a workpiece and receive fluid from a single pressurized fluid source. A fluid (e.g., hydraulic or pneumatic) circuit causes the actuators to extend during a closing stroke of the gripping apparatus according to the force equalization principle. Each actuator includes an end effector pivotally coupled with an actuator rod and configured to contact a surface of the workpiece at exactly two points. A backstop configured to contact an end face of the workpiece is coupled with a rotational joint.