Over centre mechanisms will make your designs more effective - Guide with examples

[@MrCucitrice]

Please make more videos like this in the future. Learning about simple mechanisms that could be incorporated into my own designs is super useful. You did a very good job of explaining this one and it’s potential use cases.

[@joaosimoes5508]

Quick tip on rigid over-center mechanisms. By Hooke's law, sigma (tension) equals E (Young's modulus) x epsilon (strain). And strain is given by deltaL (in the case of the video Arm lenght delta) divided by L (lenght of the part that is the replacement of the spring or rubber band). Combining both we can see that for the same elongation (deltaL) the bigger the part, the smaller the tension. When switching from PLA to PETG, one plays with the Youngs Modulus, which is lower on PETG, hence creating less tension for the same lenght and elongation of the part. This is what makes it more elastic. As always, great video.

[@giuseppebonatici7169]

yeap, instead of switching, he could just make a planar spring (like a sinusoidal slender segment) and you should be fine. PLA makes quiet good spring (because of their comparative high young modulus, you need less mass to store the same energy compared to other plastics) if you design them well (limit max deformation to low values (no more than 6%)) and in applications where the spring forces only matter at transient states (so you avoid creeping)

[@joaosimoes5508]

@@giuseppebonatici7169 yes but that kind of deviates from my initial consideration. The shape you are mentioning, and pretty correctly, would be a spring itself. I'm talking about rigid parts. If you can call them rigid. He he he

[@Kalvinjj]

@@giuseppebonatici7169 Very important last bit, was gonna comment on that, PLA having as much creep potential as it does, any PLA spring would be necessarily unloaded most of the time to be reliable in the long therm (heck maybe like, days). I always go with ABS whenever possible for any part that stays loaded in a way or another, when not possible PETG is my go to material.

[@satibel]

something something everything's a spring

[@joaosimoes5508]

@@satibel indeed it is. However the trick in this is the balance and harmony of plasticity and elasticity. Given that you can't change the parameters at will, you have to go through the design route. And that requires some knowledge on materials and/or "touch".

[@timothysands5537]

I'm a MechE student in my 3rd year and while I already knew about this mechanism and learned how to design them, it can't be understated how valuable it is to see real examples like these. Thank you for making this video, I now have more ideas on where I would apply this mechanism that I may not have thought of before!

[@NtaksAKAKevin]

Hello from Greece from a fellow designer. I would like to thank you for all the effort you put in your videos and we are all grateful for the knowledge that you spread. The way you do it is really informative and fun, and your videos have saved me countless times, I can't be thankful enough.

[@absentmindedprofesor]

I'm very grateful for your videos for this reason: You don't need to exaggerate your voice or use lots of gimmicks to keep attention. You're just a likeable guy with a voice that doesn't grate on my ears. It's refreshing. Oh and you have good content. Equally important lol.

[@n8bot]

I am a fan of this content. Been subscribed for years, afaik, but this "jumped the shark" in a good way for me. Maybe I haven't been paying enough attention to your channel, but I love this. Thank you. The concept of breaking down design concepts of specific mechanisms is marvelous, and your presentations are always nice and concise.

[@machgt]

I love using over center mechanisms in my designs. (and I'm a mechanical engineer who's been doing it for years)

[@nobocks]

Do you have some links who explain all of those mecanism ?

[@sriramneravati5048]

What other systems do you use?

[@mrlik7916]

bro I cannot put into words how thankful I am you've made this video, I've been trying to design a waterproof lid on a new product I hope may save lives down the line and I've needed exactly this information but not come across it until now. thank you so so so very much!!!

[@ASmallGreenBean]

Wow, this has to be a series for other mechanisms as well! - That would be exactly what I have been searching for a long time! Love the deep dive!

[@jakemeyer8188]

Weirdly enough, I've been doing a lot of research of late because I have a need for such a thing, but have been having a hell of a time finding such specific info. Your timing is impeccable!

[@BaldBozo]

This type of mechanism can also be used in reverse. Think of a gas strut on a concession window. The strut holds the window open, but when closed, it will reach a minimum compressed strut length and begin to extend a bit when nearly closed. This keeps the window from opening. 😊

[@That1Engineer]

With teachers like you i might have actually enjoyed mechanical design in college! This is such a good video and explanation! Thank you!!!!!! I'm the least mechanically inclined person you'll meet and this made sense.

[@tsstn]

Michael, thank you so much for your continuous contributions. There are certainly more reasons not to have a youtube channel than to continue working as hard as you do to put out such fantastic content. Thank you. I learn valuable information every time I watch your videos.

[@leonmusk1040]

I made a drawer lock and release mechanism out of a broken biro and a broken barrel slide lock which had lost its lock pin five minutes with a grinder and way more blood than would seem appropriate for a tiny puncture wound winding the spring setup I'd made. Gotta love brass cuts they just keep leaking. Now you can open and close the drawer without it going past the end point and pull a tag to release it to access the dishwasher.

[@antongoulko6641]

Please make more of videos like this!!!!! You explained it so well, and I loved how you showed real life examples

[@blzahz7633]

Agreed.

[@BloodyMobile]

While PLA is objectively a bad material for any "spring" mechanism, it's worth noting that layering single perimeters next to each other offers more "springyness" vs the same thickness as a fused perimeter. Same principle as thin stranded wires in cables vs the stiff single strand ones. Many individual thin strands can flex much easier than one solid one that exceeds compression on one side and tension on the other.

[@Ebani]

While many people say a bigger nozzle can produce stronger prints i've found the opposite to be true bc of the reason you stated, i speak from experience working with figurines, tended to prefer bigger nozzle sizes until i realized it.

[@polycrystallinecandy]

Do you mean have air gaps between perimeters? It makes sense that it would bend easier, but will it really help with elongation?

[@BloodyMobile]

@@polycrystallinecandy Yes, that's what I meant. And the answer is "kinda". As stated, PLA is awful when it comes to being a spring. But material structure is quite intruiging and the finer you go with a given material, the more "springy" it becomes. The best example are modern phones, or to be more precise, their accelerometers. These are nothing but nano scale silicon parts that flex with amounts that would shatter the same material if it were a millimeter thick. Same way how the fine stranded copper wires can be bend and twisted fine (within reason), while the single strand versions, meant for permanent placement, would work harden and break rather quickly from the same bending and twisting. Obviously, when printing springs with this approach, it comes with the cost of less stiffness. So experimentation is needed regardless. But the lifetime of the flexing parts would be drastically higher. Another benefit, more related to PLA in particular, would be that it's likely that only one spring "strand" would fail at first, and not the entire section. Since PLA often tends to reach critical failure with little warning, it would help to have several points that all are stressed differently in the same section, that way some can fail first as a warning before all have failed. But this depends highly on the design and applied forces. One design might even be better off, once one or a few strands have broken, another might overload all of them at once.

[@Sir_Uncle_Ned]

It's amazing how something so simple can be so useful! Thanks for helping me understand these mechanisms!

[@67BigMarc]

Michael. Since getting into 3D printing, about a year ago, I have gone through the progression that I think most of us have, which is download stl's then changing the original design to fit our needs then start to design our own stuff. On the final step, what do we do, hit youtube and figure it out. After much browsing I decided on blender. It works very well, but it's very confusing. While hitting youtube regularly I found a few people that I liked to go to all the time. CHEP, BV3D, and a couple of others. But I am SOOO glad that I found you! Because of you I switched to Onshape, and LOVE IT! You also explain things very well and make it easy to understand. Please keep up the GREAT content.

[@tinplategeektoo]

You can tell you were a teacher previously as this video is an excellent explanation of "over centre mechanisms". Been using them for decades but never thought about the how do they work? Now I know. A thumbs up seems inadequate thanks but of course, I have.

[@thechannel8x]

Dude, please keep making these videos - these theories has/will outlive us

[@seabeepirate]

Nice! That one latch is still over-centered, it’s just also a compliant mechanism, so a compliant over-center latch. Also, in the cutout that affords the springiness, the narrow ends of the hole being round will extend the life of the mechanism. Those sharp points are more likely to spawn cracks as well as taking longer to print than rounded profiles.

[@nuxboxen]

Excellent Video, you have always been the absolute top of the KZbin achievment.

[@sourabhk2373]

Thanks for the incredible video!

[@your_uncle_barry_6700]

I really wish you'd taught me in school. You are a great teacher. You explain things so well

[@johnpomaro1731]

You truly are an educator, sir!

[@steveg2277]

He really is haha. He’s a teacher.

[@Fishbone4u]

👏👏👏Well done! I would love to see more videos like this one. Your excellent explanation and visuals via the CAD graphics as well as showing your multiple iterations up to the final product help make this concept much easier to understand! Thank you my friend!

[@retiredtom1654]

Very well done. I did not know you were a teacher however, it clearly shows in your presentations.

[@ooslum]

11:19 is an impressive bit of timing, an ever growing car or cheeky editing. Good tut.

[@squidcaps4308]

These kind of tutorials are what i truly do need.

[@Javierm0n0]

I didnt go to school for engineering but i ended up designing a mechanism like this for a weight set i have. Its fantastic.

[@Jackbrick101]

Very educational and a well made video, would love to see more like this!

[@mograms]

Always been fascinated by this mechanism. Thank you for the great video!

[@christopherbowersdresser4188]

outstanding video man. ive been searching for this type of mechanism for a while now but i diddnt know what to call it, let alone decode the hows and wheres. over center makes all the sense in the world. im working on a sliding table saw and needed a way to lock in place on 20mm linear shaft, with the help of this video all my questions about this specific mechanism were answered. and anything that i wasnt totally sure of became very clear as i constructed the mechanism in cad. thanks a million bro!

[@captainnapalm8207]

Needed this for a project I'm working on right now. Great timing! Thanks!

[@KevOXO]

Thank you for a simple explanation of a handy method. I am guessing from the school footage, your classes were far from what I remember school being like, almost pre-recorded monotone "Open your books to page..."

[@farmeritos]

Really nice explained, really nice examples and a lot of effort, thank you!

[@OhHeyTrevorFlowers]

A handy and clear video! Thank you.

[@sentinelau]

Thanks for the video Michael, fantastic tutorial!

[@ctpctp]

Awesome vid. One thing - the "center" that makes it "over center" isn't (from your first example) the center of overall travel, but the center of alignment 90 degrees away from that point. In that example the center line of the rubber band is in line with the center line of the swinging bar...and then goes "over center" to latch. Same in the vise grip if you watch its bars move.

[@UsatMVS]

Awesome video, really enjoyed learning about such simple and yet ubiquitous mechanism!

[@Hazdazos]

Nice. Been using these kinds of designs for years but never knew the name of them which of course makes it that much more difficult to research them. Good stuff. If you need video ideas, by all means do other mechanisms.

[@markjmaxwell9819]

Just one part of engineering, and they are very helpful toggle clamps on jigs and fixtures being an example. Vice grips also use an over centre mechanism. Heavy doors sometimes need them on the hinges to help stop bounce.

[@Baldavier]

Love learning about mechanics in 3d printing life

[@AwesomeBrixx]

This is a fantastic video. Great explanations and examples

[@sconkur]

I was looking for such a mechanism. Thank you so much!

[@m97120]

More of this. That was amazing!

[@stevenschmelling5597]

Great video! Thank you for making it and sharing the launcher design. To answer your question, with a bit of question, I think it depends how you you define mechanism. I think as in most things, simpler is usually better, and you have a fairly simple multipart mechanism. But if a mechanism is just another name for machine, then I would go even simpler and say that an inclined plane is just about as good as it gets. A little more complex and an axle is a pretty great one as well. Interestingly enough, you used both of those as parts of your various mechanisms. And if the whole point of the title, and question was just to get pedantic folks like me to comment, well that also succeeded. Thanks again for doing all you do.

[@Allazander]

Interesting video. I'm currently working on and extruder design that will use an over the center mechanism to hold back the spring pressure on the idler carrier for easy filament removal/insertion. I didn't know the mechanism had a 'name' so to speak, I just knew how it worked and thought I could apply it in the extruder design. When the 'release' lever is lifted, it will lock at just over center for filament insertion/removal, when the lever is pushed down, it will go over center and allow the spring pressure of the idler carrier to take over again. This should allow for adjustable pressure on the filament via the usual thumb screw/spring assembly and easy filament insertion/removal via lever/over center mechanism. I hope so anyway. I've been tinkering with the idea on and off but the design is still in very early stages at the moment.

[@charizard3312]

Very informative! Havent heard of this one before, very much appreciated this video

[@hackaxl]

Such a great presentation - thanks for putting together because it’s so helpful.

[@vdiallonort]

Please do more video about mechanism like that It was very very interesting.

[@akerr123akerr123]

great vid, like others have said: I would love to see more with this format

[@Moostery]

No way! This is one of my absolute favorite mechanisms too!

[@JohnMazz]

I love love this! Definitely you should make more videos like this in the future!!

[@mynameisben123]

Wow crazy you made this today, I was just looking into the mechanics of vise grips.

[@testi2025]

Having a curve in the latching part makes it a spring. Here you can carefully tune it so that the range of motion when it’s flatting on the top position is not too much. Also print it so that the layers are length wise.

[@ericserafim7954]

Your videos are fully of knowledge. Thanks for sharing!

[@arax20]

Loved this vid, felt really understandable and intuitive. I think it'll be very helpful in my designs.

[@electricsheep2305]

It was an awesome video, I would love to see more mechanism videos!

[@matthewdriver334]

Excellent work! Please create more content on different mechanisms.

[@willofthemaker]

Thanks for the video! Been needing to design a mechanism like this and this is a big help.

[@NirreFirre]

This type of content makes me set notifications to "All" 🍻🤓

[@BeefIngot]

In my experience PETG is great at first, but as it absorbs moisture or ages by some other mechanism I am unaware of, it gets weaker and notably more brittle. Just a potential warning. I do find that you can design around stiffness with a more framelike /skeletonized structure.

[@Kalvinjj]

For any such mechanism that stays loaded during operation, PLA is definitely not a material to rely on, PETG has a big advantage here and ABS much more so, not because of stiffness, but creep. You wouldn't want your latch to suddenly loosen with time, but with PLA it will happen, and it won't even take that long. PETG handles creep much better and ABS is the king as far as I know without going into extremely expensive engineering polymers. Would love to know good materials on this property as well in case anyone knows.

[@olafschermann1592]

Great idea and presentation!

[@MCsCreations]

Pretty fascinating stuff! Thanks a bunch, Michael! 😃 Stay safe there with your family! 🖖😊

[@emmamarx9284]

Fantastic video! Thank you! 🙏

[@sine35video]

Fantastic tutorial, thank you!

[@therunophil]

explaining how a latch works that everybody has used a million times sounds pretty boring to me but oh boy is this an interesting video that gave me more understandig of the function and I'm sure will help me with future designs.

[@doogssmee9742]

What great timing ....... Im in the middle of designing a switching duel extruder system. And have been pondering how to do this with a servo, but then thinking can the servo hold enough pressure for long enough to keep everything accurate without burning out. Along comes teaching tech with over centered locks ..... mmmm Im thinking whilst watching "how can I use this to help me ...... Then the car launcher ..... yes that will work for me ..................... now get back to designing it lol

[@iTeerRex]

Another very simple very useful very cool mechanism is the humble flexture.

[@avejst]

Great video as always Thanks for sharing 🙂

[@Sembazuru]

If I may suggest one more thing to add to the CO2 dragster launcher. Some sort of safety interlock. Because it just take a sharp slap to get it to fire, that creates a hazard for use. My first thought (it might not be the best, take this as a brainstorming idea) is to add a servo. I'd probably use a 2 horn servo attachment. One of the horns would hold the firing pin in it's cocked position, the other horn with some sort of spring to pull it into safe position should there be a power outage to the launcher. I was at first thinking of another bi-stable mechanism on the safety, but if the firing mechanism is sensitive enough to fire with a sharp slap, then the vibration from "snapping" the safety open might cause the firing mechanism to fire. Though, I suppose a simple pin through holes in the side panels would work just as well and be simpler...

[@suivzmoi]

this is actually great for PLA which has a very bad tendency to creep even at room temperature meaning it is a terrible choice for parts under constant tension or compression as in most fastening mechanisms--except for over center mechanisms which do not store any compression or tension in the fully open or closed positions, only temporararily!. excellent!

[@guilhermetroianpagnosiguim5040]

Valeu!

[@sprsnprchkn]

Great video! I think I'll use this info for a latching clamp for an extendable pole. The clamp uses 4 M3 screws right now and is a pain to remove.

[@andymuzzo8568]

This brings back memories of high school

[@PARitter]

One of your best videos ever!

[@TigeroL42]

An over-center mechanism without a sear would make up for an incredibly smooth and dangerous gun trigger 😀 I wonder if set triggers actually work this way, pushing the hammer close to a over-center state but not past it and locking it with a second less loaded sear? Don't know too much about guns but just came into my mind..

[@gangadharaiholimath9488]

wonderful video, thank you so much

[@Frrk]

Never knew what this was called, thanks!

[@medienmond]

I would have loved having you as my teacher...

[@d._k.p.1216]

Now I know how to open a bottle of beer! That's what the iron bracket is there for! ✌ Please make a detailed analysis of the operation of buttons on trousers in the next video. Thank you in advance! ❤

[@TheOpticalFreak]

Very nice video! Great detail and explanation!😃👍 Personally I have always been fascinated by the clicking mechanisms of ballpiont Pen's there are a lot of rotating and actuating verities! Maybe it's fun to make a video about that and make a really big one with maybe an paint marker or sharpy or eddiing ink marker inside it! 😁😉

[@lunaumbra5179]

love this kind of video. great job

[@chain3519]

This is a good example of quasi stability

[@WeekdayWeekend]

I really would like a more in-depth video about the locking mechanism used at 3:45, teaching us how to properly model something like that.

[@musikSkool]

The safe trigger guns use is pretty cool. Even if you drop them the gun doesn't go off.

[@amania9254]

Informative ✌ Good content 👌 thus I has to subscribe 😊, thanks!

[@ChrisHalden007]

Great explanation. Thanks

[@markoberkes982]

Very nice video. I would be very interested to see how would you make an adition that would wind your launch mechanism so the whole process could be automated. Thanks for sharing :)

[@nigelhungerford-symes5059]

Very cool video, thanks.

[@stetco64]

Its so cool, thank you very interesting.

[@RixtronixLAB]

Nice info, thanks for sharing it :)

[@Roberto1444]

Nice content, great teacher!

[@TheIronHeadRat]

Thanks for the video 👍

[@andyspoo2]

I've never seen anyone animate OnShape sketches before. I've never thought of doing that, but I will in the future.

[@automaticprojects]

I love these videos. So informative and practical. Knowing that PETG is better for a plastic that stretches makes me wonder whether Nylon would be even better? I assume TPU is too flexible, and assume ASA and PC are too stiff?

[@TeachingTech]

I think Nylon would be ideal. It's just harder to print.

[@TheDistur]

We did co2 cars in shop class. I took mine home and put Estes motors in it and ran it on the road lol. Rural area good times.

[@timkarsten8610]

Really good video!