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We have a claw machine that grabs a bunch ping pong balls that then drops them onto an incline that leads them to a 2 inch in diameter pvc pipe that they must all fall through.

The issue is that when dropping several ping pong balls at once instead of falling into the hole multiple balls will block each other from the entrance and they are so light gravity doesn't seem to help.

The balls need to be light as they are because they are shot through a leaf blower after falling through the tube.

enter image description here

We've tried various shapes of inclines that funnel to the pipe. For example a bowl with a hole in the middle but that seemed to cause the same problem.

We are currently at a convention showing this so a solution that would require just a trip to a nearby cvs would be ideal.

Anyway we can make it so the balls don't jam themselves into the entrance?

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    $\begingroup$ Add vibration, or a rotating "cup" to pick a ball. $\endgroup$
    – Solar Mike
    Commented Jan 6, 2023 at 16:38
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    $\begingroup$ a rotating sweeper arm $\endgroup$
    – jsotola
    Commented Jan 6, 2023 at 17:22
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    $\begingroup$ AS @SolarMike states, vibration will help. Before trying a sweeper arm experiment with a high angle feeding funnel, whose angle is greater than 45 deg to the horizontal. Something around 60 deg. I'm even thinking that the height & diameter of the funnel might also have an effect. $\endgroup$
    – Fred
    Commented Jan 6, 2023 at 18:40
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    $\begingroup$ Changing the size of the exit hole will also have an effect. The Principle of Hopper Design might be useful. Answers to Ideal funnel design for powders might be of interest. $\endgroup$
    – Fred
    Commented Jan 6, 2023 at 19:00
  • $\begingroup$ A cheap solution which would need experimenting with is just a series of upright sticks that prevent the scenario shown in the photo. $\endgroup$
    – Greg Locock
    Commented Jan 6, 2023 at 20:17

1 Answer 1

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enter image description here

Figure 1. Option 1.

Try a baffle on the right. This should be a little less than the radius of the ping-pong ball so that balls approaching from the right will roll away from the hole and fall into the gulley some distance from the hole.

I suspect that the oversized rectangular opening is not helping. Try making it a little larger than required by the ball.

enter image description here

Figure 2. Option 2.

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  • $\begingroup$ Figure 1 seemed to work! Balls end up piling to the right of it but I don't mind as long as the tube is unobstructed. $\endgroup$
    – Amy
    Commented Jan 7, 2023 at 17:25

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