I bought a cabinet intended to stand. But I decided to put it on its side on the refrigerator. That means the lid does not stay open when you lift it up. So I decided to make a latching mechanism which will ensure that the lid stays open and you can operate it with just one hand. Of coarse you can buy it everywhere, but where is the fun in it.

(If you want to download STP go to my printables page: https://www.printables.com/cs/model/950899-latching-mechanism-for-opening-lids-heavy-duty)

I was browsing youtube videos (https://www.youtube.com/@MrTech93) showcasing various mechanisms and one in particular caught my eye. So I decided to model it and test it. Everything works now so I count it as success. Everything is 3D printed, even the spring.

I printed the size I needed and modified it with hand tools until it worked. Than I printed a smaller one to see if the changes work even after modifying the models. The smaller model is a ⅓ scale version just to play with it and figure how does it work.

Functionality:
When you pull OM-02 than the spring pushes on OM-03 and forces it to glide on one side of the groove. Than OM-03 is pushed into a slot restricting the mechanism to close. When you open it some more, than the spring slots into OM-03 cut out and keeps it in open position until the whole mechanism is closed fully. There the spring jumps out of the cut out and pushes on OM-03 again.

Assembly:
The piece OM-03 slides into a piece OM-01 through the hole on the right side. The spring is put into the piece OM-02 and glued in with a super glue. Than you rotate piece OM-02 90° and put the pin through piece OM-03 while opening the spring. Now you just rotate the piece OM-02 back to 0° and slide it in. See attached pictures. Disassembly is the same but in reverse.

Than just add corresponding hinges on both ends and secure it with snap-in pins. Mount the hinge OM-05 with screws to the cabinet and for the slider OM-09 you can use double sided tape. See photo with mounting dimensions. I suggest using reusable double sided tape to find just the right location for it to work properly. In the picture there are dimensions of my cabinet as well. For different cabinets you might need to move slider OM-09 differently. The OM-10 is a stopper to stop the mechanism from sliding out, but I found that it is not necessary.

Printing:
I printed everything out of PLA. You can use any material but the spring should be from PLA because of stiffness. Everything is oriented correctly, ready to print. I recommend supports in pieces OM-6 and OM-8 in the clearence slots of the snap pins. Supports are a must in piece OM-01 and OM-09 but only in the groove. The inside is short enough to print as a bridge and removing the supports would be really hard.

You can print the ⅓ scale model which has modified tolerances. If you scale the model differently than it might not work because you are scaling the clearance fit as well. But the original model works a lot better because of stronger spring.

Layer height 0,3 mm, 3 perimeters and 20% infill for all of the parts

Final words:
It has still room for improvement. The piece OM-02 should be longer to not get stuck when opened fully. But than it would not be possible to assembly it and it works now so why to change it.