[SML] Solenoids

[Paul Guncheon]

<<I'm venturing into the world of solenoids for the first time. I'm
looking to use them to drop objects from the grid. So probably an 8-16 oz.
load applied at 90 degrees to the shaft movement. Basically a loop of sting
holding the object slides off the end of the shaft, object drops to ground.
Does anyone have any advice/pitfalls to avoid? Are there quiet solenoids
out there, or do they all have that snap/click when they get powered.>>

I have used solenoids to drop / release stuff literally hundreds if not
thousands of times, so I might have a few pointers. As far as my experience
has revealed, all solenoids "snap" when energized. You can build them into
a "soundproofing" container to help with the noise if that's a problem. You
cannot add rubber or foam to the unit. Doing so will just make the solenoid
'rattle' or 'bounce', which is even worse. Another option is to attach a
'throttle control cable' release device to the solenoid which gives the
opportunity to move the solenoid further away from where the drop takes
place. If anyone is interested in how to make one of these, contact me off
list and I'll try and get a photo to you.

I have usually fashioned drop 'triggers' with the solenoids to do any drop
or release tricks. This involves a couple of eyebolts inserted into a
plywood base onto which the solenoid is also mounted. The stiff wire is
attached to the acting arm of the solenoid and is threaded through the
eyebolts. The metal ring or wire loop (no string... it will not always work
as it gets hung up on the wire attached to the solenoid) is attached to the
object to be dropped and is placed between the two eyebolts. The stiff wire
attached to the solenoid is passed through one eyebolt, the ring, and then
the second eyebolt. When activated, the solenoid pulls the stiff wire back
through the two eyebolts, releasing the ring. There are a few tricks that
help make the trigger problem free, which I can go into if anyone is
interested.

I'm sure that the above description is about as clear as mud. If anybody
needs a clearer explanation, contact me off list and I'll see if I can get
a photo or two up online to help with the description.

Laters,

Paul 1
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