Daniel Reetz, the founder of the DIY Book Scanner community, has recently started making videos of prototyping and shop tips. If you are tinkering with a book scanner (or any other project) in your home shop, these tips will come in handy. https://www.youtube.com/channel/UCn0gq8 ... g_8K1nfInQ

Lever Actuated Platens

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Joe Reeser

Re: Lever Actuated Platens

Post by Joe Reeser » 04 Mar 2011, 14:55

I did a little revamp on the spring assist. I changed the spring to one that is longer and bigger around. Here's the difference in the two springs:

Image

Now that everyone is thrilled with that here is the spring assembly with the platen up:

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Here is the assembly with the platen lowered:

Image

And here is the spring assembly holding up the platen. If one were to accidentally let go of the lever the platen would drop about 1-1/4" and then stop because of the spring tension. If your hand slips off the lever while lowering the platen below this point, the platen simply stops moving. The spring will stop the downward movement but is not powerful enough to raise the platen on its own.

Image

I like the looks of the single spring much better and it works just as well. With the larger spring, a slight push on the lever is required to set the platen all the way down. As noted above, the platen will not lower by itself with either spring assembly.

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daniel_reetz
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Re: Lever Actuated Platens

Post by daniel_reetz » 04 Mar 2011, 16:13

I've never seen a compression spring like that, with the wire insides. Is it a standard thing? Neat stuff.

StevePoling
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Re: Lever Actuated Platens

Post by StevePoling » 04 Mar 2011, 16:37

I wonder whether the sliding/nested PVC pipe would admit a pneumatic/hydraulic approach. Remember that idea using a turkey baster to push the shutter? Perhaps a bellows with a LOT more volume would work with a foot-pedal to lift the platen. Anybody got an old pump organ laying around?

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Gerard
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Re: Lever Actuated Platens

Post by Gerard » 04 Mar 2011, 17:02

i always dreaming of a cordless drill with a thread bar in its drill chuck and a nut on the thread bar,
cordless drill are cheep, strong, have a power supply and the force can be adjust, the controller can be throw out and the power supply can be connect directly to the motor and then it is very easy to control the motor with a switch

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jck57
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Re: Lever Actuated Platens

Post by jck57 » 04 Mar 2011, 18:04

StevePoling wrote:I wonder whether the sliding/nested PVC pipe would admit a pneumatic/hydraulic approach. Remember that idea using a turkey baster to push the shutter? Perhaps a bellows with a LOT more volume would work with a foot-pedal to lift the platen. Anybody got an old pump organ laying around?
http://www.horrorseek.com/home/hallowee ... cCylinders

Joe Reeser

Re: Lever Actuated Platens

Post by Joe Reeser » 04 Mar 2011, 18:34

daniel_reetz wrote:I've never seen a compression spring like that, with the wire insides. Is it a standard thing? Neat stuff.
It's standard storm door hardware. It's supposed to help keep the wind from whipping the door open too hard and breaking the hinges. I saw one at Ace hardware today for $5.29. Didn't buy it 'cuz I already have two. :mrgreen:

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