What Gizmo maker won't, some day, need a Mechanism that will transform a continuous rotation into a move-pause-move one?
That's the Geneva Wheel!
And the question is, where do you get a Vector Drawing of the parts, so you can Laser cut/3D print/machine from a template/whatever?
I've managed to make these parts in sgv format, from an Online Geneva Drive Generator, great program, highly configurable...
But I've not got an Svg directly! No such luck...
And that's why I've made this Instructable.
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Step 1: Go to the Online Program, and Set Your Geneva Wheel
Want a 5 positions Geneva Wheel, a 6 one, a 12 one?
You can set the drive crank radius, the Geneva wheel radius, the number of positions, the pin diameter, and the
Want to see it work? You can animate it.
When you're happy with the results...
Step 2: Snapshot It, and Open the Page on Gimp
Do the Ctrl-Print screen trick, and voilá!
A Snapshot of the page.
Save that, and open it with Gimp.
Step 3: Select the Moving Parts Window
On Gimp, use the select tool to grab the part that's needed, the anim window.
Copy that, and open a new window just with that.
Step 4: Color-select, or Fuzzy-select the Geneva Wheel
Color-select, or Fuzzy-select, either one of them will get you a separated Geneva wheel selection. Copy that.
Step 5: Open a New Window, Save the Png.
Open a new window, so you can get an image with a transparent Background, you then can save it as a Png.
An important note, when you save it, set the canvas size larger than the Wheel, and center the Wheel, so there's a border all around.
Step 6: The Drive Crank. Ugh!
Yes, you will get a cropped image, but it's still usable, you'll see...
You just use the 2 parts that are still intact, the grayish ones, directly, and the cropped disk, as a template, for a same-size Circle.
Step 7: Now, Inkscape
Open, then, the separate parts onto Inksape, using Import.
Step 8: Trace Bitmap
There's an operation, do Part>Trace bitmap, and the image will be traced, by color.
Step 9: A Vector Drawing!
What you have, now, see the yellow Wheel, is a vector part, that can be sent for Laser cutting and what not.
Step 10: Tricky Bits
Now for that severed Png, the Drive crank.
Just start drawing circles, and place each one so as to emulate the size and position of these ones, here, you have the larger one, under the Png, in Yellow:
Step 11: 4 Circles
Here you have the 4 Circles, 3 of them, for the 3 parts, and the big Blue one, (with the diameter of the Geneva Wheel), for making a Boolean operation.
You subtract that one from the central Circle, the Red one...
Step 12: Presto!
An all-Vector drawing, from a cropped picture!
You just have to subtract a small Circle, in the middle, for the Axis...
Step 13: Done!
All you have to do, now, is to cut all those parts, and you'll have a Geneva wheel.
Here, you see an 8 position wheel, it can have any number you want, within reason.
Go and make one!
Participated in the
Invention Challenge 2017