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  • Author Author: Former Member
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Color'er - update 1

Former Member

While waiting for the kit to arrive, I've started to think about the mechanical aspects of the challenge.

 

Simple acts are sometime difficult to model as they're so simple that we don't really think how we perform them.

The action of taking a cap off involve 3 forces (A, B & C), A & B are used to hold the 2 parts (sharpie & cap) and need to be performed at the same time while the third force (C) will take them apart and should be performed after A & B (while A & B are still on).

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To understand and illustrate this a bit better, I've 3D printed a basic "tool" that can be usee to manually take cap off a sharpie.

 

Bolts are used to hold the sharpie and its cap, they simulate A & B.

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Once the sharpie and its cap are hold by A & B, a simple lever is used to take them apart. This lever simulates C.

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and ... it works!

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That's the simple part of the challenge, now the real thing can starts...

 

PS: You'll notice that LEGO Technic pieces are very useful when 3D printing quick prototypes! image

  • in reply to jw0752

    That's clever, thanks!

    I've quickly printed "a foot" to test this approach. I now need to find some grippy material for it.

    To increase the contact surface, I might also try to Vee-shape it but it might then be harder to stick the grippy material.

    I am using old steel blade saw for the flexible arm; I might need to stack 2 blades to provide enough friction.

    imageimage

  • Hi David,

    I thought about your problem last night and came up with this alternate approach. I have mocked up a simple prototype and attach the pictures. You are welcome to the idea which will need some work and updating to work practically.

     

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    This principal will allow the use of different size markers and caps to be accommodated by the flexible spring arms. The action can be worked by pinching or you could expand it so that body weight could be used or even a pincher like a pliers. While I have used spring steel for the arms they could also be lever arms with spring loads and the contact to the marker could be more of a foot with a pad. While I have used double sided tape for this demonstration there are lots of non-slip materials out today that would likely be more appropriate. Like I said use the idea if you wish but it will need some more work and experimentation to be really practical.

    John

  • in reply to Former Member

    To help tracking comments on that particular approach, I have just created a dedicated thread here.

  • in reply to mcb1

    I never heard/saw such oil filter remover so I didn't even consider that approach but that might be worth a try.

     

    Right now, I am thinking about the following approach with 'rubber wheels'.

    image

    Wheels would turn in opposite directions using pulleys (and thus can be driven from the same motor).

    What I also need is the 'move' one set of wheels towards the marker to produce the required friction to move piece apart. 

    I am looking to buy the necessary parts to prototype this, this might take a week.

    In theory, that approach (it it works image) would allows to use any type of sharpie (inc. flush ones).

  • in reply to Former Member

    David

    Very good point about the flush marker, and the zero user friction.

     

    The cap replacement is also worthy adding to V2.0.

     

    I've used Oil filter removers that use a simple thin web belt with the socket rotating and tightening the webbing.

    They remove nearly every stubborn filter I've tried ... plus they fit in tight spaces.

    image

     

    It got me wondering if something like this that grabbed each end and then pulled apart might be a possibility.

    The benefit is that simple geared servo motors driving the 'tightening' might be easier to integrate.

     

     

    Mark