# Something old, Something older---



## Brian Rupnow (May 26, 2013)

This morning its too cold to play outside, and I'm bored.--Which is not necessarily a bad thing. I have been perusing my booklet "507 Mechanical Movements" by Henry T Brown, looking for some kind of intriguing mechanical "eye candy" to possibly build. This is a little booklet choc full of all kind of nifty mechanical devices that were invented at the beginning of the mechanical revolution. Some of them were great devices, which are still in use today in modern machinery. Some are ideas that worked and were used for a period of time when mechanical things were transitioning from steam power to gasoline power, and some of them were probably only ever built once, just to see if they would work. A device that caught my eye this morning is item #27, which is listed as "Multiple Gearing" with the following description:--"A recent invention. The smaller triangular wheel drives the larger one by the movement of its attached friction-rollers in the radial grooves." There are no measurements nor geometric relationships given, only the picture shown here. I thought "Hmmmm---That's interesting!!! I wonder if I can replicate that and sus out the geometric relationships in Solidworks?" Good wife was still in bed sleeping, so I snuck downstairs to my office, fired up the computer, and found out that "By Golly, I can!!!" Of course the next question was, what do I have to run something like that? A static display just doesn't cut it. In my room devoted to small steam and gasoline engines which I have built over the last five years, there is the sad remains of what once was a very proud "Hit and Miss" air engine originally designed by Chuck Fellows over on HMEM. It ran marvellously, but I had cannibalized parts off it and used them for other purposes, and the main corpse has been laying around for two years now, waiting to be resurrected as something new. A few measurements and some deep thought has suggested that I should be able to use it as the main engine for a dynamic display of this marvelous old "Multiple Gearing" idea. So--as the summer advances and I get downtime from other work and play, I will be building this.----Brian


----------



## dnalot (May 26, 2013)

I have this nifty little book and half worn it out paging through it over and over again. I especially like the oval and square gears. We should all have a copy.

Mark T


----------



## jwcnc1911 (May 26, 2013)

How funny, I thought every one had a copy of this book!

For those of you who don't...

http://507movements.com/


----------



## Brian Rupnow (May 26, 2013)

Of course, nothing in life is easy. I lost all of the 3D cad models of this engine a few years ago when I had a major computer crash. Fortunately, I have many of the files of my different steam engines stored as pdf files on a web hosting site, so I was able to download a set of the plans and recreate all the solid models. When I first built this engine and made the drawings based on Chuck Fellows design, I posted the link as a free download, and I see that it has been downloaded 588 times. Now that I have recreated the models, I can move foreword with the "Multiple Gearing" design.


----------



## Brian Rupnow (May 27, 2013)

I went thru my random collection of spur gears today, and found a couple the right size for what I have in mind. Last night I decided that the determining factor on how big I made the large disc with the slots in it would be governed by how big a disc I can hold in the chuck on my rotary table. I checked tonight, and the largest is 4" diameter, so this works well with the 3.75" dia. that I had in mind. the design is basically done. Now all I have to do is find the time to make some parts!!!


----------



## itowbig (May 27, 2013)

that looks like a fun one


----------



## Brian Rupnow (May 27, 2013)

Here we are at step #1. Two pieces of 1/4" brass plate, roughed out on the bandsaw, then finish turned in the lathe using the "double sided carpet tape" method. This is some of the brass plate that some gentleman in the USA so kindly sent me. One of the discs gets the slots cut into it--the other has a stub shaft silver soldered into the center so this thing can rotate when its all assembled.


----------



## jwcnc1911 (May 27, 2013)

Brian, just found this on a website I frequent and thought you may enjoy it:

http://grabcad.com/library/multiple-gear-drive-1


----------



## wildun (May 28, 2013)

Thanks you BRIAN, DNALOT and JWCNC, - sure helps to fill my mind with ambitious projects again now that I've just got a decent size lathe, - I think that there is enough stuff here to see me out!


----------



## jwcnc1911 (May 28, 2013)

Brian,

What software do you model with?  That background color and fade looks like Allibre's default.

Just curious.


----------



## mikegw1961 (May 28, 2013)

Jwcnc1911

Brian is using Solidworks.


----------



## jwcnc1911 (May 28, 2013)

Thanks, me too.  As well as Inventor and Allibre.


----------



## Brian Rupnow (May 28, 2013)

jwcnc1911 said:


> Brian,
> 
> What software do you model with?  That background color and fade looks like Allibre's default.
> 
> Just curious.


Solidworks!!!


----------



## Brian Rupnow (May 28, 2013)

I know that the steam engine works. It worked as Chuck's Hit and Miss in its first life, then it was reincarnated as the "Doodle Bug". The part I'm not sure about is the "Multiple Gearing", so that seems like a good place to start. I centered my rotary table under the quill of my milling machine, and with the two pieces of brass still together, mounted on a short 1/4" dia. shaft, I mounted them in the 3 jaw chuck which lives on my rotary table. I wanted my angular divisions to be very precise, so I mounted the divider plates on the rotary table to get a good level of precision. I first drilled thru all the plates with the correct size drill for an 8-32 tap, then drilled clearance holes 1/4" deep thru only the top plate, then lacking a #8 counterboring tool, I used a 5/16" endmill to counterbore for the #8 socket heads. Then I tapped thru everything in place and inserted the #8 socket head cap screws. Then it was just a lot of "back and forth" with a 3/8" dia endmill until I was completely thru the top plate. You will see that the center area of the topmost plate is now gone, but I still have the 1/4" reamed hole in the second plate down.


----------



## Shopguy (May 28, 2013)

Looks like you have made a good start on your "Radial Grooved Trammel"
I recall looking at the picture of the mechanism in my own copy of "1800 Mechanical Movements" and thinking it was a clever way of off setting two shafts, drive and driven.
Looking forward to your continuing build posts.
Ernie


----------



## Brian Rupnow (May 29, 2013)

Today I made up the shaft for what I am going to call the "star wheel" and got it silver soldered into place. Then I spent what seemed like an inordinate amount of time machining the "spider", and then careful measuring confirmed that I had "chuffed it up".  One arm is perfect from center hole to hole in end of arm---One is .020" short, and one is .020" too long. I'm not sure how I managed that, but working of co-ordinate measurements in the mill without using the rotary table sometimes yields rather unusual results (for me). Its not a total loss though. The holes at the end of the arm are reamed 0.125". Tomorrow I will stop by my tool supplier and buy either a 5/32" or a 4mm endmill and move the holes around a little bit. Since I am making up the shafts that fit into the holes, I can do that. The shafts will be silver soldered into the spider, and I think that in order to work as intended, they have to be "spot on".


----------



## Brian Rupnow (May 30, 2013)

Well---I can say this much--IT WORKS!!! Its still at the dirty nasty stage, but a bit of time with the fine sandpaper and polishing buffs will take care of that. However, I have "driven" the spider around the starwheel  by hand, and it actually does work the way I had hoped. At the last minute, I decided to use 638 Loctite instead of silver solder.


----------



## ConductorX (May 30, 2013)

Brian,

Either the axle on the three pointed driver would have to move in a wierd pattern or the driven wheel. What kind of pattern does it make? Or am I all wet?

Your stuff is always amazing and I own a copy of that book as well.

"G"


----------



## Brian Rupnow (May 30, 2013)

ConductorX---Your'e all wet!!! See the link---
http://grabcad.com/library/multiple-gear-drive-1


----------



## ConductorX (May 30, 2013)

You didn't give me a towel.    It is a cool device, just have to find some work for it to do.

"G"


----------



## Brian Rupnow (May 30, 2013)

HooAwwww--Lookit them suckers go!!! I will admit to a certain amount of camera induced frenzy, causing me to call my mill a drill press, but other than that----Is this ever neat!!!


----------



## jwcnc1911 (May 30, 2013)

I gotta say, I'm liking this alot.  I'm looking forward to seeing a working model of this!

What are you going to drive with it?


----------



## Brian Rupnow (May 30, 2013)

jwcnc1911 said:


> I gotta say, I'm liking this alot.  I'm looking forward to seeing a working model of this!
> 
> What are you going to drive with it?


 Damn Man!!! Go back and read the whole post. I've given you a verbal description. I've posted pictures. I've posted solid models!!!  If you are too lazy or unwilling to read the whole post, then don't bother looking at it.---Brian


----------



## Brian Rupnow (May 30, 2013)

And yes, if you were interested enough to read the posts, you deserve some drawings. (Now that I know it works!!!)


----------



## Brian Rupnow (May 30, 2013)




----------



## Brian Rupnow (May 30, 2013)




----------



## wildun (May 31, 2013)

Brian, I haven't studied it a lot as yet but I guess with this type of mechanism, whatever the number of legs are on the spider (with slots to suit), the reduction will always be 2:1 or 1:2 (depending on which one is the input) ?


----------



## Brian Rupnow (May 31, 2013)

Wildun--I haven't studied on it al that much myself. I know that the radius on the spider is 0.75" and the slots in the starwheel are 3" long. If you look at it in terms of diameters, it is a 2:1 ratio. I don't know if other ratio combinations are possible or not.---Brian


----------



## jwcnc1911 (May 31, 2013)

Very nice Brian!  Thank you for sharing your drawings.

I have the theory that a 2:1 ratio is optimum.  It looks like other ratios will work but...  If you go any higher the samller driving gear will not reach as far to the circumference of the driven gear and will result in lower efficiency.  Like moving closer to the fulcrum on a lever... you need to be farther away to amplify force.

Fantastic work in making this thing happen though, very skillful!  I'm now trying to find an application for this.


----------



## wildun (Jun 1, 2013)

Brian Rupnow said:


> If you look at it in terms of diameters, it is a 2:1 ratio.Brian


Brian,
I got that idea from watching the animation, - if you watch one of the legs on the spider carefully, it will move from one end of a slot to the other end of that slot (in one revolution) so that means the large wheel (slotwheel?) will have turned thru 180deg. So, 2 revs of the spider = 1 rev of the slotwheel and as far as I can see the case would be the same with with a two legged "spider" (if that's possible ), but I need to add that I could be wrong!
Anyway, you seem to have done a sterling job!


----------



## jwcnc1911 (Jun 1, 2013)

wildun said:


> Brian,
> I got that idea from watching the animation, - if you watch one of the legs on the spider carefully, it will move from one end of a slot to the other end of that slot (in one revolution) so that means the large wheel (slotwheel?) will have turned thru 180deg. So, 2 revs of the spider = 1 rev of the slotwheel and as far as I can see the case would be the same with with a two legged "spider" (if that's possible ), but I need to add that I could be wrong!
> Anyway, you seem to have done a sterling job!



The ratio would still be diametral, like a gear with more or less theeth, the pitch only changes.


----------



## Brian Rupnow (Jun 1, 2013)

I don't expect anyone to make the following part. It will work only with the particular engine that I am using. This is really more about "method". First I draw and dimension the part. Then I print it out at onene scale and cut it out, then glue it to a piece of cereal box cardboard. I line up one of the non critical edges with an edge on the material which I intend to cut it from, which has been coated with layout dye and trace around the edges with my scriber. Anywhere that there is an internal radius, I use a centerpunch to punch thru the cardboard template and leave a center punch mark in the metal. Then its a trip to my vertical bandsaw, to cut the pieces out, and over to my mill drill to drill out holes at the "punch" marks. On any critical mating surfaces, I leave about .030" of material to be milled off. Anywhere that it is just a "cosmetic" surface which doesn't mate with anything, I carefully "cut to the line" with my bandsaw, and will finish those areas with a hand file..


----------



## Brian Rupnow (Jun 1, 2013)

Well, its been a very worky day, but a successful one for all that---


----------



## wildun (Jun 1, 2013)

jwcnc1911 said:


> The ratio would still be diametral, like a gear with more or less theeth, the pitch only changes.



 Always the same ratio (2:1)  - I'll accept it if you prove me wrong!


----------



## jwcnc1911 (Jun 1, 2013)

Brain... would you be willing to send me your solids to save me a little time playing with this?


----------



## Noitoen (Jun 2, 2013)

I wonder if the "surface speed" of the outer diameter of the driven wheel will maintain constant as it goes a complete revolution. I would think that there will be slight "speed ups" and "slows down" as the rollers travel along the different angle positions on the slots. It should be interesting to watch in slow motion.


----------



## jwcnc1911 (Jun 2, 2013)

Noitoen said:


> I wonder if the "surface speed" of the outer diameter of the driven wheel will maintain constant as it goes a complete revolution. I would think that there will be slight "speed ups" and "slows down" as the rollers travel along the different angle positions on the slots. It should be interesting to watch in slow motion.



Angular speed will be the same.  "surface speed" or surface footage will be diametrically relative... Larger the diameter, the higher the surface footage.


----------



## Noitoen (Jun 2, 2013)

jwcnc1911 said:


> Angular speed will be the same.  "surface speed" or surface footage will be diametrically relative... Larger the diameter, the higher the surface footage.


I don't think so. If you look at the typical crossed universal joint, when it's at an angle, it accelerates and decelerates twice in each revolution.


----------



## Brian Rupnow (Jun 2, 2013)

jwcnc1911 said:


> Brain... would you be willing to send me your solids to save me a little time playing with this?


Yes--Send me your "real" email address on the "private message" function and I will send you a download link to the solids models.---Brian


----------



## Brian Rupnow (Jun 2, 2013)

If someone can explain how, I will upload the file to the HMEM site and then anybody interested can download the solid models and drawings. I have them zipped up and they are only 1.8 Megs.


----------



## jwcnc1911 (Jun 2, 2013)

Noitoen said:


> I don't think so. If you look at the typical crossed universal joint, when it's at an angle, it accelerates and decelerates twice in each revolution.





The axes are parallel, not at an angle like a UV joint.  Surface speed, or as most machinist refer to it, surface footage, is a linear conversion of rotational speed based on circumference.  Most tooling manufacturers will provide you with a recommended SFM as a starting point for feed/speed calculations.

Check out that PDF I put a couple posts up for formulas.


----------



## Brian Rupnow (Jun 2, 2013)

Okay---I'll try this. For all you Solidworks guys out there,  am posting a zip file of all the drawings, models, and assemblies.--2011 Solidworks. 

View attachment MULTIPLE GEARING ASSEMBLY.zip


----------



## Brian Rupnow (Jun 2, 2013)

This has been the perfect size of project.---Start one weekend, finish the next weekend. Everything works very well, and gives me another shelf sitter, to go with all the other ones.!!!


----------



## 110samec (Jun 15, 2013)

That looks very good and it looks to be good runner  Have you thought about painting the large pulley a different colour so that it would be easier to see the triangular piece's movements? Looks very good as it is, it was just a thought I had 
Cheers,
sam


----------



## Brian Rupnow (Jun 15, 2013)

110samec said:


> That looks very good and it looks to be good runner  Have you thought about painting the large pulley a different colour so that it would be easier to see the triangular piece's movements? Looks very good as it is, it was just a thought I had
> Cheers,
> sam


Paint brass that can be polished??? Good Lord man, that's almost sacrilege. I see what you mean though.---Brian


----------



## old-and-broken (Jun 15, 2013)

Wonderful re-creation of this old mechanism!

I do apologize to everyone for adding this piece of almost non-relevant data before hand.  I do not want to distract from Mr. Rupnow's great contributions to this fine forum.

That being said, it was pointed out by another member that the drive would suffer accelerations and declerations.  There would be three such per revolution of the three legged member.  The torque profile being sinusoidal in nature and having a max velocity point coinciding with the configuration where the three legged member has one leg fully inserted into its mating slot and the slowest velocity with that member in the position with two legs engaged an equal distance in the corresponding slots.

My math is VERY rusty, but the deviation would be a little less than 3%, as best I could figure it.  Analytical Geometry is many decades in my past and my memory is akin to a block of swiss cheese these days. 

But YES, a very sporadic drive method where consistent peripheral speed is desired, otherwise a beautiful symphony of mechanical motion and a joy to behold as it revolves.

Thank you for the wonderful creations Mr. Rupnow.


----------



## jwcnc1911 (Jun 15, 2013)

Brian, do you have a tachometer?


----------



## Brian Rupnow (Jun 15, 2013)

jwcnc1911 said:


> Brian, do you have a tachometer?


No, not one that I would trust.


----------



## old-and-broken (Jun 15, 2013)

Black and white stripes and a strobe perhaps.  Something like the markings found on those ancient things known as record playing turn tables?
I am guessing it is desired to measure the rotations and see the deviations?


----------



## jwcnc1911 (Jun 15, 2013)

Yes.  I'm sorry, I can't help but disagree on the speed change.  While you have one pin ramping out of the the driven wheel you also have one ramping in.  You can take several sample points along the path, calculate rotational speed.  If it only had to driving pins at 180 degrees separation I would agree, but you have three with a minimum of two in contact at all times, while one is decelerating the other is accelerating at the same rate resulting in no change in rotational speed to the driven wheel.

I guess I could put pen to paper or either make one myself but that takes time that I'm short on.  I'd like to see your calculus - that will convince me.  I can't help but think if you were to graph this it would be a perfect parabola.  I think at the point where the two driving pins are equidistant you would not have deceleration, you would have found the point where the two velocities happen to be exactly the same, one decreasing, one increasing.  But for that one moment, the same.

This is the most I've had to think in a long time.  I like it.


----------



## Charles Lamont (Jun 15, 2013)

The output speed is constant. This needs no calculus. It is a simple matter of the geometry of an isosceles triangle.

Practically, of course, it has to be constant, or it would not work.

If a spider arm is at angle x from the bottom, its follower slot is at x/2.

Theoretically, the spider could have any number of arms, given an equal number of diametric grooves in the follower.


----------



## old-and-broken (Jun 15, 2013)

I used a differrent analytical approach from the old school I was 'learned' in.  The mesh of two gears can be simplified into two smooth surface cylinders and speed is calculated from the mesh surface radii.  Normal toothed gears have a very small variation in mesh surface radii that is normally ignored in calculating the ratio between them.  The mesh surface radii in this case is substantial and the difference between the contact radius when two 'teeth' are engaged equal distance in the slots versus when one tooth is engaged at full depth in the slot is large enough to make a noticeable difference between the driving speeds at those points.  

I agree, this has made me think and I am enjoying it immensely.   

I may have to model this myself just to find out.


----------



## jwcnc1911 (Jun 15, 2013)

Charles Lamont said:


> The output speed is constant. This needs no calculus. It is a simple matter of the geometry of an isosceles triangle.
> 
> Practically, of course, it has to be constant, or it would not work.
> 
> ...



First, thank you for confirming what I was already thinking.  However, I disagree with your triangle approach as proving a relationship between the angular speed of both wheels.  It only proves the relationship for any given &#934; that there is an equilateral triangle thus proving the relationship of the pins to the diametric slots.

You can set up any triangle you want, only &#934; and opposite are static.





Imagine the spider has one pin.  Will the speed of the driven wheel vary in that situation as the pin distance to center of the driven varies?

Triangle on the left, pin is farther from driven center, triangle on the right, closer:





To prove they have the same angular speed you need to set up an equation to determine the angular speed of the larger driven wheel while the pin is traveling from closest to center and vis versa while it is traveling from farthest to closest.

Like calculating cutting speeds around a blended radiused corner to get constant surface feed.


----------



## Charles Lamont (Jun 17, 2013)

I think you are blinding yourself with science.

You agree there is a linear relationship between the angles. For a constant angular velocity of the spider, you can graph the follower angle over time. Start with both at the bottom, and call the angle zero. Whatever the spider angle is at some later time, the the follower angle will be half that. It will be a straight line graph. The slope gives you the (constant) angular velocity of the follower.


----------

