Saturday, July 16, 2016

Balls Be Lockin'!

Well, soon enough at least!

This is what I've come up with so far.
Should be fairly easy to manufacture; Five sheets of 10 mm plywood/board with standard drilling/sawing at most and a couple of 2 mm aluminum details etc.

1) Left: Open state. The holder solenoid bracket is spring loaded against the main solenoid plunger, and once the main solenoid triggers and the plunger reaches the endpoint, the bracket pushes forward and locks it in place. Right: Closed state. The holder solenoid and main solenoid is inactive and springs are doing their thing together with physics. When it's time to open I'll fire the main solenoid briefly to release tension, hold the holder solenoid while the plunger drops and then release the holder solenoid.
There are a few eyeballers here, but overall it should be pretty correct. The "fork" itself is based on a couple of bolts I have (with the screw part sawed off in the design) and they are a little shorter than I would like them to be. I will also have to double check that the ball won't squeeze through the gap. In case it does, I'll have to drill new or bigger holes in the playfield since the captive ball posts where 2-3 times larger than these bolts.

Should shit hit the fan, I got a couple of blue steel ramp flaps that can be placed on the playfield "floor" to cover up any unwanted holes. But I really hope it doesn't come to that! :)


  1. I have a similar design but different. I have the same kind of ball lock, two bars pop up and trap it. originally i was going to just PWM but I dont want to pwm + power the solenoid for long periods.

    what I did different was use the solenoid to push the lock up, and instead of using something to hold the solenoid bar up at the bottom, I have a mechanism at the top to lock it so the solenoid can spring back down.

    fire it up, pwm for a second or two to let the servo arm move over and hold it, unpower solenoid... when ready, just drop the servo arm!

  2. I have a used pinball part that does exactly this, using 2 coils. Heres a couple pictures. hope they help you with your design. I am missing the larger of the 2 coils however im sure you can figure out whats happening.


    1. I forgot to mention what might be obvious, it is a modified pop bumper assembly. should make it easy to replicate.

    2. Thanks for your reply and pictures!
      Yes, this does indeed look similar to what I had in mind. :)

      I'm currently toying with the idea of an autolocking port, that simply releases immediately if not locked (similar to the right Sword-ramp release on Lord Of The Rings). I'm out of ports and basically only got one left... :)

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