Disengagement Canister

Howdy, wonderful people!

There's something so satisfying about twist-locking containers, whether it's a fancy magnetic latch setup or a traditional screw thread. However, there's also something quite nice about containers where the lid remains attached when the thing is open, and those two concepts don't mesh together easily. Of course, I've put some together in the past, where a twist-lock lid hinges away from the body, but you'll notice that they all have at least three pieces since the lid and the body require some kind of intermediate that talks both their languages.

I thought: is there a way to do this with just two parts, no connecting intermediary? Actually, I thought that a long time ago, and I've explored many a dead end on the topic. But, it occurred to me that it would be possible to make a hinge that could be disengaged and re-engaged via the lid rotation, and that turned out to be quite a useful idea! And that's what this model is - A container with a rotating lid that has part-time hinges!

Now, the trick turned out to be how to constrain the rotation of the lid so that the hinge parts stay together, while still allowing rotation when the lid is closed and needs rotation in order to lock.

There are a couple of different mechanisms:

* The most obvious one is the huge flange on the lid hinge parts. When the lid hinges open, those flanges hook into the box body and the hinge is held secure. However, those flanges need to stay out of the way for lid rotation, and the clearance to allow that means they don't hook in for the first part of the lid opening...

* Fortunately, the locking mechanism in the lid helps out here, too, preventing the front of the lid from moving sideways until the lid has opened sufficiently.

* Meanwhile, an interior rail at the hinge side of the lid hooks into a matching groove in the box body and keeps the rear of the lid from being lifted open without impeding the actual hinge motion.

* Last but not least, there's a slab pin to the left of the space between the hinge pins, and that slides into a channel in the lid, again keeping it from being moved sideways through the first part of the hinge motion, until the lid moves clear of the box body.

It works pretty well! However, what we're trying to achieve here is fundamentally tricky: We want rotational motion to be free and unimpeded when the lid is closed, but completely prevented when the lid is hinged even the tiniest amount. The mechanisms above are designed to achieve that, but ultimately the tolerances of the print mean that you can certainly move the pieces apart if you want to! Besides, even if that wasn't a concern, we're making things out of flexy plastic here, and that does facilitate pulling things apart somewhat :)

Print Description

This is an articulated, print-in-place model so make sure your first layer is nice and neat and that there aren't any print artifacts like stringing or overextrusion that might bond moving parts together!

Optional Magnets

If you'd like to put nice, satisfying magnets in the locking latch, you'll need two of our old favourites, the 6x3mm cylindrical magnet. They are by no means essential, however!

Print Dimensions

The Disengagement Canister occupies 188mm x 98mm on the print bed and is 66mm tall.

Supports Needed?

Not at all!  Designed for straightforward printing!

Scalability

The main issue with scaling this one is that the magnets will no longer fit, but they aren't essential, anyway. You'll probably have more luck scaling up than scaling down, since looser tolerances will potentially work against you. But then again, just experiment with it and see! :D

Print Orientation

The Disengagement Canister prints base-down, with the lid folded open.

File Location

You'll find this one at at 483 Disengagement Canister

Link to dropbox post: https://www.patreon.com/posts/31697592

Further Thoughts

I did consider putting a magnet in the hinge, as a second "locking" position, but that was more for a satisfying clunk than as a necessity - it wouldn't really add any security that the designed mechanisms don't provide. However, it does make me wonder if it would be possible to build this kind of mechanism using magnets alone! Imagine if the hinges were simply flat faces with magnets embedded in them! It's worth a try! :D

Happy printing!

xoxo

Sven.