Ball Drop Iris Mechanism for Consistent Impact Testing
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Solution Overview
Problem
Existing ball drop test apparatuses for evaluating roofing material resistance to impact damage, such as hail, suffer from inconsistent results due to variations in the retraction of the steel fork and potential contact between the falling ball and the pipe, leading to unreliable test outcomes.
Innovation Solution
A ball drop iris mechanism featuring triangular iris petals with recessed ball seats that uniformly hold and release a 2-inch diameter steel ball, ensuring consistent release and descent down the test tube by retracting petals upon user activation or with an electric solenoid, thereby minimizing contact with the tube's inner surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a steel fork is used to hold and release the ball, then the ball can be released from the pipe, but variations in fork retraction and potential contact with the pipe inner surface create inconsistent test results
Solution Approach 1:
The holding mechanism is divided into multiple independent iris petals instead of using a single fork. Each petal can move independently to hold and release the ball, eliminating the variability associated with single-fork retraction. The segmented structure allows for more precise and consistent ball positioning and release.
Solution Approach 2:
The iris petals are designed to pivot dynamically between closed and open positions controlled by a control ring. This dynamic mechanism allows precise control over when and how the ball is released, eliminating the inconsistent retraction behavior of static fork structures. The controlled pivoting action ensures repeatable ball release positioning.
2Speed
If the pipe diameter is made large enough to accommodate free fall, then the ball can fall freely, but the ball may contact the inner surface of the pipe causing inconsistent results
Solution Approach 1:
The iris mechanism acts as an intermediary between the ball and the pipe inner surface. By using the iris petals to hold and release the ball at controlled positions, the system prevents direct contact between the ball and pipe inner surface during the critical release phase. This intermediary mechanism ensures consistent ball trajectories without relying on large pipe diameters.
3Device complexity
If a simple pipe structure is used, then the apparatus is simple, but variations in fork retraction and ball contact create unreliable test outcomes
Solution Approach 1:
The simple pipe structure is enhanced by segmenting the holding mechanism into multiple iris petals. This segmentation adds complexity only where needed for reliable ball holding and release, while maintaining the simplicity of the overall pipe structure. The segmented iris mechanism provides consistent results without requiring complex modifications to the entire apparatus.
Solution Approach 2:
The control ring mechanism allows for parameter changes in the iris petal positions, enabling precise control over ball release timing and positioning. This parameter control capability improves test reliability without fundamentally changing the simple pipe structure, adding control functionality only where necessary.
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 ball drop iris ensures consistent and controlled release of the test ball, reducing variability in impact testing results and providing more reliable evaluations of roofing material resistance to environmental impacts.
Implementation Method 1
or remotely with the use of an electric solenoid
Implementation Method 2
A steel ball is dropped down a tube made of PVC plastic or the like, the pipe having a diameter large enough to accommodate the free fall of the steel ball
Data Source
AI summary
A ball drop iris is provided for use in a ball drop testing apparatus. Included on the iris is a lower housing having an upper mounting flange having a ball opening and a body depending from the flange, the body defining a passage through which a test ball passes. A control ring is disposed on the upper mounting surface for sliding, rotating action relative to the lower housing. A plurality of iris petals is provided, each operationally connected to the control ring and to the upper mounting flange to pivot between a closed position in which the ball opening is blocked, and an open position in which the petals are simultaneously retracted and the opening is clear for passage of a test ball.