Back in the early 90's this mechanism was used to create an "Automatic" gear on a bicycle as it had this mechanism spring mounted and used the torque placed on the pedal to reduce the diameter of the drive gear.
What was the reason why this wasn’t continued after the 90‘s? Looks quite superior to stacking different sized gears next to each other.. and would eliminate the gear switching problems..
There's a mechanism called a variable transmission (I know its used in mopeds) that this reminded me of. It's basically two bowls spring loaded together at the base like this )( When the speed increases, the centrifugal force pulls the pulley apart )-( so it becomes a smaller diameter pulley system. Different mechanism, but same idea behind it.
Since it's out of copyright, you can find all of the movements online if you search for the title on Google. It's a cool site to click through from time to time.
@@tye2876 I'd expect some helical tracks, some parallelogram to move them... well... parallel. Also maybe some springloaded detent to keep everyting in place.
I've seen this mechanism used for expanding tables. The ones that spin and have the leaves come from underneath and then lock in place. Very satisfying design.
That's exactly what I want to do myself one day. Hopefully author will take a look at this comment and will try creating a 3d printed expanding table so we can try this ourselves. Probably others will proceed with the bigger versions of it 😅 Anyway, a great video there! Thanks a lot 🙂
That mechanism is gorgeous and I love that you've modeled and 3d printed it. It's way easier to understand once you see it in motion in the real world.
@@MakersMuse Dude the locksmith lawyer will not be impressed. A magnet lock can easy be hacked using a magnet and then rotating the wheel by hand. You need to connect it to a pin locking mechanism which releases the wheel when it begin rotating when the correct key is inserted that would need to be part of the gear key. Also making an organic tooth path and hiding the teeth under plastic will mean you'd have to capture the dimensions of the regular key and the gear itself.
@@pavellelyukh5272 You forgot that this was a puzzle box, not a lock to secure valuables with. The Lockpicking Lawyer deals with the latter, not with the former. In other words: concerns he would raise are entirely irrelevant to this video.
@@AhsimNreiziev actually locks are puzzles. Magnets aren't because the effect is too global. Imo a puzzle requires the manipulation of objects in 3-6DOF to work so unless you use a extremely advanced magnet with selective polarity you'll basically only have 2DOF puzzle
Hi Angus, this this expanding pulley design was used in the design of an underactuated robotic finger in this academic paper: Underactuated Gripper That Is Able to Convert from Precision to Power Grasp by a Variable Transmission Ratio (Spanjer, Balasubramanian, Dollar & Herder, 2012) The finger has two joint both actuated by the same tendon, which passes over a pulley at each joint. By changing the size of radius of the lower joint's pulley, the stability of the finger tip force and grasping capability of the finger could be changed while still retaining some of the major benefits of an underactuated finger.
Two thoughts: 1) expanding pulleys (or whatever they are called) are used in a centrifugal force clutch mechanism, like in a scooter. 2) pulleys are often use with ropes and they do not need to be concentric/circular to work.
Agreed, my 1st thought was the old massive leather belts used on 19th century machines (looms and machine shops with 1 engine powering multiple machines). The design could be used as a speed control if a idler tension wheel is used to compensate for the diameter change.
That is not for a clutch system, period. It's made to adjust the ratio of a pulley system, so the speed of the drive chain can be speed up or slowed down. Pulleys use ropes, chains, belts, tracks, or anything that is flexible, so as long as the shape is rotating, it doesn't matter what the shape of the pulley is.
@@Tom-yc8jv The so-called "clutch" (actually governor) on a motor scooter is belt-driven, so it could potentially work with that. However, I don't think most do.
They actually are for flat belts! Their purpose is similar to the purpose of the CVT but not identical. Ive seen them in manuals for machine tools from the 1920's and older but never owned one myself. Specifically for shapers, otherwise known amd arm-strong's These tools are so rugged even from the 1920's they still are in use in modern shops who can afford the space for them or shops that need skiving done like you se in copper semiconductor heat sinks! But they are very rarely made today, because of low demand and high market saturation, it really is an under appreciated machine tool. I could not hide my excitement to see a piece of it resurrected for a modern use!
@@MakersMuse This is primarily just a thought, but I imagine if each pin was offset slightly beginning the motion, you could likely achieve an almost revolving opening pattern, where each locking lug opened sequencially
The expanded pulley has exactly the same friction contact area with the belt as when at the minimum size. There are many, many small vaults and lock boxes that use a system like this, but only to drive 3 bolts (up, down and the locking side, though sometimes there's a 4th, but that's normally where the lock bolt blocks the rotation) with the plate driven by the outside handle. Nice project! I'm also impressed you can get Fusion to move things that smoothly in the animations with contacts on!
Just finished this, Angus. It's both ingenious and magical! My little granddaughter is going to love it on Christmas day. Thank you so much for a truly great design. I'm now printing out your egg puzzle. That'll keep everyone quiet!
I was thinking of this for an expanding wheel a while back. My plan reduced the effect of the individual sections creating flat spots by utilising a stack of these offset from each other. I also added a rubber pad that compressed more at the peak of each section. I was attempting to make a bicycle wheel that could reduce diameter for easier use on public transportation. It works reasonably well.
@@MakersMuse No a scroll chuck is different again; A longworth chuck uses plates, one with left hand spiral cutout and one right spiral cutout, back to back
Came here to say the same thing. Looks just like a longworth chuck. I wonder how much more "bite" you could get out of a longworth chuck by driving it on a gear... Tried to use one once for a non wood turning application and was surprised at how little holding torque it had. (Could have been because I made it... lol)
I've always been bugged by how the hands in oval shape clocks don't adapt their lenghts to the oval shape. This mechanism might solve it so I can finally rest in peace
When I was little, square clocks were in fashion, particularly in cars. The hands moving in circles really bugged me! :) I think a static cam could be used to change the hand lengths whatever the shape of the face.
You asked for real world use of this contraption? It is being used in a coil holder in a factory that specialises in sheet metal products. They have the sheet metal delivered in big coils and then flatten it. The device that holds the coils in place has four of these (slightly more robust than you 3D printed version) paralel to each other on a central axis. The main benefit being that it can pas trough the smaller hole in the flanges of the coilholder and uses a rotating movement for engaging the grip. So unrolling the coil automatically engages de spreader and centralises it. Keep up the fun work.
This mechanism is used in a woodturning tool called a Longworth chuck. Unsurprisingly, the Longworth chuck suffers from some of the same issues mentioned here.
It's a table that has been around for some time now. The whole table gets bigger and adds a rising centerpiece that settles in to fill in the gap. As for a pully the tee shaped outer ends need to overlap while small.
I’ve seen this design used for an amazing expanding round table that had extra pieces to fill the gaps rise up from the middle at the same time as the table expanded
Most in floor safes use a similar mechanism to withdraw 3 bolts allowing the safe head to be lifted out with a handle. The better ones allow you to remove the dial, and some have specific dials that are offset from others, so without the correct dial AND the combination, you can't open the safe. I can provide photos if you like. Added: Also, the entire Wheel is the Cam, the Pins are pulled and pushed by Channels in the Cam which drive the Bolts, your bolts have arcs attached in the early version, but they are still bolts. A Cam is any driving device set to pivot on a single point.
There are expanding tables that use this mechanism, and they have leafs that move into place with the spinning motion to fill in the gaps. In this way you don’t get an adjustable pulley as much as one with two distinct sizes. The tables look super cool too!
I love seing such mechanism. Is it just me or wouldn't it be very satisfying to see this driven by a motor like a safe :P. You well deserved a new patreon support for your hard work!
the mechanism shown at 2:29 is widely used in the Efteling themepark in the Netherlands. Motorised disks with bumps and dips in specific patterns make the actuators move, which in their turn pull and push cables to make various animatronic figures move.
Back in the 1800’s this design was used to adjust vanes inside water turbines that ran flour and grist mills and early factories that were water driven by rivers. They needed to compensate their RPM and torque for the machines based on different water conditions before and after big rainfalls, different seasons ect.
What I found amazing is that you kind of look like a high-school student with extreme interest into this exciting subject, but at 8:16 you look like a teacher in that subject
Okay, I know it's been a year since this video was uploaded but if you care to re-visit the idea a few suggestions may improve its performance. 1.) Thicken the wheel to at least double its current thickness ...so that the pully can actually be used as such. You know how pulleys have that groove for the rope to go through! 2.) Print it so that the arcs are hollow and piece each one together with spring-loaded inner arcs [one on each end of the arc segment]. ...so that when the wheel expands each of the arc segments expands with it completing the full arc of the wheel without gaps. If I had a 3d printer and a CAD system I'd make all kinds of stuff but my home is not my own! For now, I guess I'll have to settle for my thought experiments and building stuff in my head.
When I worked at TechShop, there were a couple of guys that were laser cutting Delrin to make and sell cams for sewing machines like yours. I congratulated them on finding a solution to a very unique need.
If I can give a small improvement suggestion about the access to the gearing, you could have just covered the tooths with the casing (giving it no access from the top and side) and made the gear slide in from the side(with a pin underneath it to guide the position). It would still be hackable with a stick, for that you could add a small locker (as you did) that gets unlocked by the driving pin on the gear (the locker could put a gate behind the gear pin when it unlocks in order to prevent the double stick hack). With this modifications it could work without the necessity of 2 magnets and a spring
1) There are smaller safe doors that use this mechanism - it's not "forgotten". 2) It is possible to gear reduce - the disc is essentially a sheave on a shaft. Use a bit more imagination! 3) Back drive can be prevented by taking care in the design of the slot - you could have bought yourself more space by using two discs, and only using 3 sliding bolts per disc (enabling 120 Degrees of rotation versus ~60). Having the bolts fully extend and then having another 15-degrees of rotation of the cam disc that stays at the same extension would give the cam a flat rather than sloped surface to push back on. 4) Back drive could have been further prevented with an mechanical interlock, or either a cycloidal or worm gear primary drive (naturally resists backdrive) for the discs. I challenge you to print a split globoid worm drive. where the cam discs (globe) are driven by the worm
At my job we made a prototype of a robot to drive through large underground pipes. We used this mechanism attached to the front of the robot to expand sensors outwards so they could make contact with the pipes wall. We later scrapped the mechanism and went for something else because it didn't provide a high enough expansion ration to cover the range of pipes we were working in... It could also be used to lift and move cylinders by expanding within them creating a high friction force.
@3:43 couldn't this be useful for changing gears on a bike? you'd just have to figure out a way to avoid breaking the chain when you adjust the size of the gear.
Not with a chain it wouldn't, but with a belt drive and two microcontroller adjusted pulleys, it would work. Belt slipping? Tweak one pulley a fraction larger to tighten it.
Angus, The motion is used, but in reverse of the manner it was intended by the book. It's actually a self centering grip for round objects. This is the mechanism that a Giffin Grip uses to center pottery pieces for final trimming but the Giffin grip only uses three "spokes" verses the six shown in the video. Look up Giffen grip on Amazon. It's also the same principle behind some lathe chucks that grip and center the stock.
You could design a puzzle using the mechanism to lock in to and lift objects. A crane style puzzle? And you could build it so that the pins lock when weight is applied and release when the weight is relieved. You could include resistance to that movement to target the weight that would remain locked. That would allow you to have the pins retract unless the specified weight is applied, meaning that picking up the wrong piece would cause the piece to drop, while picking up the appropriate weight could keep it locked in place until set down. You could stack multiple mechanisms with different length pins to create an actuated key. This could be modular, so a scavenger hunt would require people to find each module, assemble them together correctly, then activate it(with a secondary key, or lever, or machine depending on resistance) to open and move a door. Or it could be used as a breaking mechanism.
That expanding pulley design was used as a basic clutch on many items of the past. Eg when power is applied, it expands outward to touch the inner surface of a tube, thereby powering the tube. Then when power was removed, the pulley would disengage and allow the tube to continue to spin unpowered with its momentum. This was used on many gates and mills just a few hundred years ago.
Three thoughts: 1. You don't have any rope grooves in the one you built. If you have a flexible rope then it may not matter if the pulley stays concentric. 2. If you place two of those at either end of a cylinder made of overlapping material you could create a spool whose diameter could be changed. 3. Changing the size of a pulley (by itself or in relation to another pulley of fixed size) will change the efficiency of the pulley (Efficiency = Mechanical Advantage/Velocity Ratio). Think about what changes, and then think of a case when that might be useful.
You actually missed a feature. The near perpendicular part at the end means that a lot of motion leads to a little movement which has the same function as a high gear ratio and makes it easier to stay in place and applies more pressure with less chance of slipping. It's also the inverse of an iris mechanism. :) Using a rotary cam to expand a circle rather than shrinking one.
To fix the gap problem, just make interlocking ledges that overlap when the mechanism in contracted. And for the magnet issues, just make the placement pin a diagonal pin, then let this pin rotate freely with the gear key, this allows you slide in the key at an angle and you can cover over the edge of the mechanism.
hopefully this hasn't been written already in the comments Before the advent of steam, many workshops used water wheels to drive machinery. The water wheel drove single shaft that rotated at a constant speed. Great, but not so useful for the many different machines in use in, say, a joinery workshop. So, in order to get differing speed final rotations, different size discs would be used as the primary gear, as is still done today in my pillar drill on my workbench. But, with differing primary gears, the problem of drive belt slack creeps in. This expanding pulley takes care of that without having to resort to using a belt tensioner (which I find on my ride-on lawnmower), which asserts lateral pressure on the belt which may wear it out quicker. Presumably the latch on the smaller gear had a release allowing the extension of the pulley arms to be eased, so accommodating the different sized primary gear/pulley. Just a thought. Either way, thanks for the vid!
8:03 you just need a really weak spring to keep the lock closed without gravity. like maybe you could cut off a little piece of an ink pen spring, or something. or maybe you could 3d print a really thin angled part to insert in the mechanism to provide tension. i don't know what kind of material would allow repeated bending like that.
Back in the early 90's this mechanism was used to create an "Automatic" gear on a bicycle as it had this mechanism spring mounted and used the torque placed on the pedal to reduce the diameter of the drive gear.
When I saw it Iwas like ummm couldnt this be used to make an automatic gear system, and there was your answer.
@@mimoslavich6639 LOL.. Same me
What was the reason why this wasn’t continued after the 90‘s? Looks quite superior to stacking different sized gears next to each other.. and would eliminate the gear switching problems..
There's a mechanism called a variable transmission (I know its used in mopeds) that this reminded me of. It's basically two bowls spring loaded together at the base like this )( When the speed increases, the centrifugal force pulls the pulley apart )-( so it becomes a smaller diameter pulley system.
Different mechanism, but same idea behind it.
@@ajsparx4133 if I understand that right that would be a transmission that automatically adjusts to speed, right? Sounds like a high tech moped...
as an Industrial designer I can say that the mechanical movements book is extremely worth the purchase
I bought this book too some days ago and it is an amazing source of inspiration
Purchased immediately after hearing it
I’m a junior in college for Mechanical engineering technology and mechatronics. Any tips on getting a internship
Since it's out of copyright, you can find all of the movements online if you search for the title on Google. It's a cool site to click through from time to time.
The website also has some flash animations of some of the mechanisms.
The expanding pulley design is used in the fletcher capstan table.
That table is a work of art! I think it might use some elements of this mechanism but it's also far more complex with the inserts that fill the gaps.
ahhh... i wanted to say that.
iam 4 hours late..
Late also,
I wonder what other mechanisms go into the table to get the pieces to open wider then close to accept the wedges moving up.
@@tye2876 I'd expect some helical tracks, some parallelogram to move them... well... parallel. Also maybe some springloaded detent to keep everyting in place.
507 Mechanical Movements is just a gold mine that needs to be explored on this channel.
I've seen this mechanism used for expanding tables. The ones that spin and have the leaves come from underneath and then lock in place. Very satisfying design.
That's exactly what I want to do myself one day. Hopefully author will take a look at this comment and will try creating a 3d printed expanding table so we can try this ourselves. Probably others will proceed with the bigger versions of it 😅
Anyway, a great video there! Thanks a lot 🙂
Yeah, the Fletcher Capstan table for 50k. Its pretty amazing though
That mechanism is gorgeous and I love that you've modeled and 3d printed it. It's way easier to understand once you see it in motion in the real world.
I predict a super sized version coming soon. :P
Ohh a huge one would be insane!
@@MakersMuse Dude the locksmith lawyer will not be impressed. A magnet lock can easy be hacked using a magnet and then rotating the wheel by hand. You need to connect it to a pin locking mechanism which releases the wheel when it begin rotating when the correct key is inserted that would need to be part of the gear key. Also making an organic tooth path and hiding the teeth under plastic will mean you'd have to capture the dimensions of the regular key and the gear itself.
@@pavellelyukh5272
You forgot that this was a puzzle box, not a lock to secure valuables with. The Lockpicking Lawyer deals with the latter, not with the former. In other words: concerns he would raise are entirely irrelevant to this video.
@@AhsimNreiziev actually locks are puzzles. Magnets aren't because the effect is too global. Imo a puzzle requires the manipulation of objects in 3-6DOF to work so unless you use a extremely advanced magnet with selective polarity you'll basically only have 2DOF puzzle
"Hexagons are the Bestagons"
-CGP Grey
All hail hexagon
@@Dragon-xd9em hail! hail!
Hexagons ARE the bestagons
Cgp grey is great :)
@@AquaB33 not really, it kinda six to be them(the hexagons.)
@@carbonbeaker409 Blasphemy!
It could be used as a fly wheel, the change in size will affect inertia, dunno where thats useful tho.
Actually that could be pretty neat! Like how swinging your legs out on an office chair slows or speeds up your rotation.
I think I've seen a similar use case in some clocks
@@MakersMuse How about variomatic?
It's also how cats rotate in midair.
I think that has been tried in perpetuum mobile ;-)
Can I just say, as someone who has never done any engineering, I find this fun, fascinating, and approachable! Super cool stuff
you and me both --- we can learn anything!!!!
This mechanism reminds me of a Centrifugal clutch that expand when torque is applied to grab an outer cylinder
I had the exact same thought when watching the vid, and came to say the same thing.
I'd swear it's the clutch on my trimmer
That's the first thing that comes to mind.
Added this same comment then wondered if I was the only one.
Hi Angus, this this expanding pulley design was used in the design of an underactuated robotic finger in this academic paper: Underactuated Gripper That Is Able
to Convert from Precision to Power Grasp by a Variable Transmission Ratio (Spanjer, Balasubramanian, Dollar & Herder, 2012)
The finger has two joint both actuated by the same tendon, which passes over a pulley at each joint. By changing the size of radius of the lower joint's pulley, the stability of the finger tip force and grasping capability of the finger could be changed while still retaining some of the major benefits of an underactuated finger.
Use for the expanding pulley: How about an omni-directional hat stretcher?
Perfect for people with big heads, like me.
Thats a beyblade
@@julethug_7361 YES YES YES YES YES!
There is an expanding table design that uses this principle in woodworking/furniture building circles.
worth mentioning this is how a lens aperture iris works. I used this type of design on my milling machine to lock the spindle via it's splines.
Very cool!
exactly what i thought when i saw it, its inverse of it
Why does this guy look so friendly and kind?
And why do I feel in 2001 looking at his face?
Probably cause he looks like Spencer from iCarly?
"And this important because it's beautiful." I like your mindset
Two thoughts:
1) expanding pulleys (or whatever they are called) are used in a centrifugal force clutch mechanism, like in a scooter.
2) pulleys are often use with ropes and they do not need to be concentric/circular to work.
Agreed, my 1st thought was the old massive leather belts used on 19th century machines (looms and machine shops with 1 engine powering multiple machines). The design could be used as a speed control if a idler tension wheel is used to compensate for the diameter change.
The 'expanding pulley' used in belt CVT transmissions use a different mechanism to move the sides of the pulley toward the centerline.
That is not for a clutch system, period. It's made to adjust the ratio of a pulley system, so the speed of the drive chain can be speed up or slowed down. Pulleys use ropes, chains, belts, tracks, or anything that is flexible, so as long as the shape is rotating, it doesn't matter what the shape of the pulley is.
@@Tom-yc8jv The so-called "clutch" (actually governor) on a motor scooter is belt-driven, so it could potentially work with that. However, I don't think most do.
They actually are for flat belts!
Their purpose is similar to the purpose of the CVT but not identical.
Ive seen them in manuals for machine tools from the 1920's and older but never owned one myself.
Specifically for shapers, otherwise known amd arm-strong's
These tools are so rugged even from the 1920's they still are in use in modern shops who can afford the space for them or shops that need skiving done like you se in copper semiconductor heat sinks!
But they are very rarely made today, because of low demand and high market saturation, it really is an under appreciated machine tool. I could not hide my excitement to see a piece of it resurrected for a modern use!
Another masterful mechanism Angus! I wonder what kind of funky stuff you could do by using different shaped slots for each pin :0
All sorts of funky motions! I'm definitely gonna keep experimenting
there have been tables using it
@@MakersMuse This is primarily just a thought, but I imagine if each pin was offset slightly beginning the motion, you could likely achieve an almost revolving opening pattern, where each locking lug opened sequencially
bro time for u to start work on new project :D
its a cam
The expanded pulley has exactly the same friction contact area with the belt as when at the minimum size.
There are many, many small vaults and lock boxes that use a system like this, but only to drive 3 bolts (up, down and the locking side, though sometimes there's a 4th, but that's normally where the lock bolt blocks the rotation) with the plate driven by the outside handle.
Nice project! I'm also impressed you can get Fusion to move things that smoothly in the animations with contacts on!
it has been used in a bicycle for an automatic transmission. Ref: Yankee bike
Thanks for that. It does seem like a pretty good mechanism for some kind of continuously varying transmission.
Yankee bike 😂 perfect
they're used in expanding dining tables!
Thanks for mentioning the book 507 Mechanical Movements. It has proved quite useful to me.
Just finished this, Angus. It's both ingenious and magical! My little granddaughter is going to love it on Christmas day. Thank you so much for a truly great design. I'm now printing out your egg puzzle. That'll keep everyone quiet!
Thanks for letting me know ! That's wonderful :)
I was thinking of this for an expanding wheel a while back. My plan reduced the effect of the individual sections creating flat spots by utilising a stack of these offset from each other.
I also added a rubber pad that compressed more at the peak of each section.
I was attempting to make a bicycle wheel that could reduce diameter for easier use on public transportation. It works reasonably well.
6:08 the spinning ashtrays segment unlocked memories from my past that I forgot I had
someone i knew had one of those, knew them a long time ago
They were onto CVT transmission for longer than we thought.
Reminds me of a longworth chuck that bowl turners use on their wood lathes
Hey you're right it is very similar to the scroll in chucks...! Great observation didn't even think of that.
And a chuck boring ring.
@@MakersMuse No a scroll chuck is different again; A longworth chuck uses plates, one with left hand spiral cutout and one right spiral cutout, back to back
Came here to say the same thing. Looks just like a longworth chuck. I wonder how much more "bite" you could get out of a longworth chuck by driving it on a gear... Tried to use one once for a non wood turning application and was surprised at how little holding torque it had. (Could have been because I made it... lol)
I've always been bugged by how the hands in oval shape clocks don't adapt their lenghts to the oval shape. This mechanism might solve it so I can finally rest in peace
When I was little, square clocks were in fashion, particularly in cars. The hands moving in circles really bugged me! :) I think a static cam could be used to change the hand lengths whatever the shape of the face.
You asked for real world use of this contraption? It is being used in a coil holder in a factory that specialises in sheet metal products. They have the sheet metal delivered in big coils and then flatten it. The device that holds the coils in place has four of these (slightly more robust than you 3D printed version) paralel to each other on a central axis. The main benefit being that it can pas trough the smaller hole in the flanges of the coilholder and uses a rotating movement for engaging the grip. So unrolling the coil automatically engages de spreader and centralises it. Keep up the fun work.
This mechanism is used in a woodturning tool called a Longworth chuck. Unsurprisingly, the Longworth chuck suffers from some of the same issues mentioned here.
I started using PrusaSlicer with my Ender 3 about a year ago. I was/am so happy with the results. Much better than I had been getting with Cura.
3 Jaw self centering metal lathe chuck : the single slot's pitch is so gradual that it engages each jaw several times
same on my old wood lathe
this is that but 6 jawed and coarser pitch
Scroll chuck.
Now we'll see how smart Popeye really is... 😅
Hahaha oh man... he'd just throw it off the balcony but I really want to find out now.
The description and diagram is very clear so yeah, it is simple! And beautifully elegant.
It's a table that has been around for some time now. The whole table gets bigger and adds a rising centerpiece that settles in to fill in the gap. As for a pully the tee shaped outer ends need to overlap while small.
The Fletcher capstan table almost certainly uses a variation on this design.
That adjustable pulley is for changing the ratio in a pulley system, to speed up or slow down the drive chain. It's still used to this day.
yeah the expending pulleys is the corner stone for modern CVT transmission
Makers Muse: "... I suspect this design didn't see very much use..."
also Makers Muse: "... it's kind of bad at what it was designed for..."
😂
I’ve seen this design used for an amazing expanding round table that had extra pieces to fill the gaps rise up from the middle at the same time as the table expanded
Most in floor safes use a similar mechanism to withdraw 3 bolts allowing the safe head to be lifted out with a handle. The better ones allow you to remove the dial, and some have specific dials that are offset from others, so without the correct dial AND the combination, you can't open the safe. I can provide photos if you like.
Added: Also, the entire Wheel is the Cam, the Pins are pulled and pushed by Channels in the Cam which drive the Bolts, your bolts have arcs attached in the early version, but they are still bolts. A Cam is any driving device set to pivot on a single point.
There are expanding tables that use this mechanism, and they have leafs that move into place with the spinning motion to fill in the gaps. In this way you don’t get an adjustable pulley as much as one with two distinct sizes. The tables look super cool too!
With the symbols it looks like it could be a prop for Stargate.
Precisely what I was thinking!
OMG, Angus doesn't hate Ender 3s anymore, the ground feels like it's gotten cooler...
;)
I would say the most regular use of this (can we call it "an extrapment-device" ? ) is in some variations of recoil starters, like chainsaws =)
I love seing such mechanism. Is it just me or wouldn't it be very satisfying to see this driven by a motor like a safe :P. You well deserved a new patreon support for your hard work!
the mechanism shown at 2:29 is widely used in the Efteling themepark in the Netherlands. Motorised disks with bumps and dips in specific patterns make the actuators move, which in their turn pull and push cables to make various animatronic figures move.
This would make for a really good cvt pulley for a cvt transmission. You could do this on a bicycle to make an automatic transmission bicycle
already been done but it cant of been that great as it never caught on!
@@billysbikes8671 that’s lame
I could see a dm for dnd giving the final version to their players and a couple sessions later giving them the key
cool box for sure
Yeah that'd be really neat! With secrets hidden inside.
I was thinking how to put this in a dnd campaign
It reminds me of watertight (or airtight) door locks, designed to secure doors against pressure differences, used in ships or passenger aircraft.
Or the one of the vault door designs from Fallout
@@Noahs80series Only FO4 111 ones. Most from before where just roll and push doors.
Back in the 1800’s this design was used to adjust vanes inside water turbines that ran flour and grist mills and early factories that were water driven by rivers. They needed to compensate their RPM and torque for the machines based on different water conditions before and after big rainfalls, different seasons ect.
Dude....What you made is beautiful...
I could potentially see it used in earlier braking systems, like early pre-cursors of drum brake systems
Or a centrifugal clutch.
*_"This Lock Box Mechanism is 150 Years Old"_*
Wow, who knew 3d printers had been around for so long?!
;D
Wwow
that simple expanding pully just gave me (in theory)a brileant idea for a comitative beyblade gimmick
I was trying to think of the same thing! No joke :O
Only I'm wayyy to new to 3d printing to accomplish that xD
What I found amazing is that you kind of look like a high-school student with extreme interest into this exciting subject, but at 8:16 you look like a teacher in that subject
You're a refreshingly pleasant presenter
I would expect the expanding pulley to work reasonably well with a V-belt.
This actually reminds me of an expanding clutch mechanism.
title : "crazy clever"
my expectation : "oh is there more than a cam?"
content: "actually it's a cam"
i feel baited....
The Virgin Machinist vs The Chad Cam Master
it's an S cam
Okay, but hear me out, what if a cam, but actually six cams at once?
Really amazing design work. Thank you also for showing "507 Mechanical Movements" wow, what a great find!
Super great use of 3D printing - mind benders.
Who else randomly got this recommended to them, but are happy about it?
Yes
I need this for my pimp'd out Magic the Gathering deck!
Damn, the algorithm has good taste for once!
Al Gore Rhythm
Okay, I know it's been a year since this video was uploaded but if you care to re-visit the idea a few suggestions may improve its performance.
1.) Thicken the wheel to at least double its current thickness ...so that the pully can actually be used as such. You know how pulleys have that groove for the rope to go through!
2.) Print it so that the arcs are hollow and piece each one together with spring-loaded inner arcs [one on each end of the arc segment]. ...so that when the wheel expands each of the arc segments expands with it completing the full arc of the wheel without gaps.
If I had a 3d printer and a CAD system I'd make all kinds of stuff but my home is not my own! For now, I guess I'll have to settle for my thought experiments and building stuff in my head.
When I worked at TechShop, there were a couple of guys that were laser cutting Delrin to make and sell cams for sewing machines like yours. I congratulated them on finding a solution to a very unique need.
he literally just made a fancier version of a cookie jar
Lol yas
Correction: He made the best version of the cookie jar.
well, a CVT belt transmission seems like an obvious use case for this
7:11 you can still open it with a magnet and without the key.
Yep, this doesn't have "that" kinda key
simple fix, give it an actual key to pull back a bolt that locks the disc in place.
If I can give a small improvement suggestion about the access to the gearing, you could have just covered the tooths with the casing (giving it no access from the top and side) and made the gear slide in from the side(with a pin underneath it to guide the position). It would still be hackable with a stick, for that you could add a small locker (as you did) that gets unlocked by the driving pin on the gear (the locker could put a gate behind the gear pin when it unlocks in order to prevent the double stick hack). With this modifications it could work without the necessity of 2 magnets and a spring
Thanks to this video, I've actually bought this book and a 3d printer!
It was used for the Chamber of Secrets!
Jk
Oh geez, I thought that at first too. LOL. IMO he missed a fantastic opportunity to recreate that door too.
I've seen this used by the Amish in designing a round table that expanded for guests.
"so you can definitely print this at home on your low end 3d printer"
snobbishly laughs in mk3s with mmu2
*laughs tediously in 3d printing pen and hours...days....weeks of patient hand work*
screw 3d prinking i want to machine this out of steel and aluminum...
1) There are smaller safe doors that use this mechanism - it's not "forgotten".
2) It is possible to gear reduce - the disc is essentially a sheave on a shaft. Use a bit more imagination!
3) Back drive can be prevented by taking care in the design of the slot - you could have bought yourself more space by using two discs, and only using 3 sliding bolts per disc (enabling 120 Degrees of rotation versus ~60). Having the bolts fully extend and then having another 15-degrees of rotation of the cam disc that stays at the same extension would give the cam a flat rather than sloped surface to push back on.
4) Back drive could have been further prevented with an mechanical interlock, or either a cycloidal or worm gear primary drive (naturally resists backdrive) for the discs. I challenge you to print a split globoid worm drive. where the cam discs (globe) are driven by the worm
At my job we made a prototype of a robot to drive through large underground pipes. We used this mechanism attached to the front of the robot to expand sensors outwards so they could make contact with the pipes wall. We later scrapped the mechanism and went for something else because it didn't provide a high enough expansion ration to cover the range of pipes we were working in... It could also be used to lift and move cylinders by expanding within them creating a high friction force.
@3:43 couldn't this be useful for changing gears on a bike? you'd just have to figure out a way to avoid breaking the chain when you adjust the size of the gear.
derailleur???!
Not with a chain it wouldn't, but with a belt drive and two microcontroller adjusted pulleys, it would work. Belt slipping? Tweak one pulley a fraction larger to tighten it.
This is very similar to a clutch system, expanding outward to engage with something at speed as it expands.
centrifugal clutch, also used in old centrifugal point distributors
aaaaaaaaaaandim now $5 poorer... happily
This is awesome and gorgeous. Great work Angus, love it.
This channel looks pretty cool, yes.
Im early today... Lol
This one video makes me want to switch from EE to ME. That is a thing of beauty. Good effort bud.
It's gorgeous. Maybe a candy jar that a *Bond Villain* would use.
Well done Angus. Model printed out extremely well no problems. Will now have to expand horizons and learn how to use Fusion 360, Thanks again
Great to hear! Thanks
Angus,
The motion is used, but in reverse of the manner it was intended by the book. It's actually a self centering grip for round objects. This is the mechanism that a Giffin Grip uses to center pottery pieces for final trimming but the Giffin grip only uses three "spokes" verses the six shown in the video. Look up Giffen grip on Amazon. It's also the same principle behind some lathe chucks that grip and center the stock.
You could design a puzzle using the mechanism to lock in to and lift objects. A crane style puzzle? And you could build it so that the pins lock when weight is applied and release when the weight is relieved. You could include resistance to that movement to target the weight that would remain locked. That would allow you to have the pins retract unless the specified weight is applied, meaning that picking up the wrong piece would cause the piece to drop, while picking up the appropriate weight could keep it locked in place until set down.
You could stack multiple mechanisms with different length pins to create an actuated key. This could be modular, so a scavenger hunt would require people to find each module, assemble them together correctly, then activate it(with a secondary key, or lever, or machine depending on resistance) to open and move a door.
Or it could be used as a breaking mechanism.
That expanding pulley design was used as a basic clutch on many items of the past. Eg when power is applied, it expands outward to touch the inner surface of a tube, thereby powering the tube. Then when power was removed, the pulley would disengage and allow the tube to continue to spin unpowered with its momentum. This was used on many gates and mills just a few hundred years ago.
Three thoughts:
1. You don't have any rope grooves in the one you built. If you have a flexible rope then it may not matter if the pulley stays concentric.
2. If you place two of those at either end of a cylinder made of overlapping material you could create a spool whose diameter could be changed.
3. Changing the size of a pulley (by itself or in relation to another pulley of fixed size) will change the efficiency of the pulley (Efficiency = Mechanical Advantage/Velocity Ratio). Think about what changes, and then think of a case when that might be useful.
I've seen mechanisms like this before and it's been on of my favorites
Nice mecanism and I love your box design
Great channel to fall asleep to
Thanks to you i came along 507movements amd used it many many times🙏
Wonderful work young man!
You actually missed a feature. The near perpendicular part at the end means that a lot of motion leads to a little movement which has the same function as a high gear ratio and makes it easier to stay in place and applies more pressure with less chance of slipping. It's also the inverse of an iris mechanism. :) Using a rotary cam to expand a circle rather than shrinking one.
To fix the gap problem, just make interlocking ledges that overlap when the mechanism in contracted. And for the magnet issues, just make the placement pin a diagonal pin, then let this pin rotate freely with the gear key, this allows you slide in the key at an angle and you can cover over the edge of the mechanism.
Wxcellent, thank you. I will be using a variation on this design to lock up smething on my boat so this is very much appreciated.
It absolutely is!
Very nice design, great work!
this is great. awesome channel
hopefully this hasn't been written already in the comments
Before the advent of steam, many workshops used water wheels to drive machinery. The water wheel drove single shaft that rotated at a constant speed. Great, but not so useful for the many different machines in use in, say, a joinery workshop. So, in order to get differing speed final rotations, different size discs would be used as the primary gear, as is still done today in my pillar drill on my workbench. But, with differing primary gears, the problem of drive belt slack creeps in. This expanding pulley takes care of that without having to resort to using a belt tensioner (which I find on my ride-on lawnmower), which asserts lateral pressure on the belt which may wear it out quicker. Presumably the latch on the smaller gear had a release allowing the extension of the pulley arms to be eased, so accommodating the different sized primary gear/pulley.
Just a thought.
Either way, thanks for the vid!
Fascinating insight, thanks!
8:03 you just need a really weak spring to keep the lock closed without gravity. like maybe you could cut off a little piece of an ink pen spring, or something. or maybe you could 3d print a really thin angled part to insert in the mechanism to provide tension. i don't know what kind of material would allow repeated bending like that.