Of electric bikes and cargo: 3D printers and thermos

So we talked about the bike. 120km under my belt on it now, story checks out. Go go gadget bike makes pedalling easier.

But one of the sad things, cargo. I mean, I don’t take much with me. A laptop. And a thermos of iced-tea (because the local iced-tea places are too fancy and have things like hibiscus and carbonated tea on tap).

A saddle-bag was acquired, and the laptop can be kind of shoehorned in there. But the 2.2l thermos. That is another story. Its big and heavy.

In many bikes, you get a ‘cage’ that mounts to the post. But this thermos is *way* bigger than a bike water bottle. And this bike has rectangular channels (full of batteries). I could remove the battery and drill+tap it I suppose. But, well, we have a 3D printer, this should be solvable.

First we get the calipers. The Thermos is 112mm diameter. The rectangular channel on the bike is 50.5mm wide.

So, lets make some math (or just download on Thingiverse).

module triangle(o_len, a_len, depth)
{
    linear_extrude(height=depth)
    {
        polygon(points=[[0,0],[a_len,0],[0,o_len]], paths=[[0,1,2]]);
    }
}

mlen = 70;
od = 122;
id = od - 10;
cw = 50.5;
ow = 60;


rotate([-90,0,0]) {
difference() {

    // outer cube W, L, H
    cube(size = [od, mlen, od/2]);
    
    // cylinder channel
    translate(v = [od/2, mlen+1, od/2]) rotate(a = [90, 0, 0]) cylinder(d = id, h = mlen+25); 

}

rotate(a = [180,0,0]) translate([od/4,-mlen,0])
difference() {
    // outer rectangle W, L, H
    cube(size = [ow, mlen, 50]);
    
    // inner rectangle channel
    translate(v = [(ow - cw)/2, mlen, 0]) rotate(a = [90, 0, 0]) cube(size = [cw, 50, mlen+0]);
}

translate( [od/4,0,0]) rotate([-90,0,0]) mirror([90,0,0])triangle(25,30,mlen);
translate( [90,0,0]) rotate([-90,0,0]) triangle(25,32,mlen);
}

And this produces the below shape. What do you think, slap that over the channel, slap the thermos in it, and run a velcro strap over it?