PDA

View Full Version : Jacobs Ladder



brian Rupnow
11-29-2011, 06:30 PM
The krazy klockwork machine is finished, and I'm not about to start something new right away, But-----A goodly portion of my 46 years in design engineering has been spent designing material handling projects. One of the more intriguing elevator type devices, to elevate either round rod or pipe sideways out of a full bin and to "singulate" them is called a "Jacobs Ladder". It works on the principal of a moving staircase. Imagine, if you will, 3 very very narrow flights of stairs, on which the treads tip in a bit towards the staircase, while the risers are vertical. In this case, say the outer two flights of stairs were cut from 1/4" plate, the inner flight cut from 1/2" plate, and all 3 set in very close proximity to each other---maybe .030" to .040" apart. The two outer flights are stationary, while the center flight of stairs "orbits". The orbit carries this center flight up the height of one riser plus perhaps 1/16", and then the orbit causes it to "sink back" between the two outer flights, complete its orbit, and once again rise up between the two outer flights and repeat---over and over again, as in continuosly. The tread area in the center flight would have a slight concavity running along it, put in by a v or ball nosed mill. Now, if a person had a supply of 3/4" or 1" diameter wooden or aluminum balls (I think steel balls would be too heavy)---and if they were "funneled" towards the foot of the stairs---. The moving center flight would pick up a ball, carry it upward, and deposit it on the next higher tread of the two outer flights. On its next orbit, it would move this ball up to the next step, while simultaneously picking up another ball. This would keep happening untill all the treads were full of balls, and they started to fall off the top step---where they would be funneled back to the base to start their journey over again. Wow!!! What a neat piece of animation that would be---especially if the orbiting mechanism was driven by a small steam or gasoline engine. In a "real world" application, for example lifting 48" long pipes out of a bin, there would be a Jacobs Ladder at each end, but for a demo unit using balls, only one ladder would be required.---Surely bears thinking about, doesn't it!!!

Evan
11-29-2011, 08:06 PM
When I see "Jacobs Ladder" I think of arcs n sparks. :)

The Artful Bodger
11-29-2011, 08:15 PM
Brian, I am thinking, is there something about your Jacob's Ladder that ensures every step if filled? That could be the basis of a novel clock mechanism and display..:rolleyes:

J.Ramsey
11-29-2011, 08:20 PM
When I see "Jacobs Ladder" I think of arcs n sparks. :)


When I think of Jacobs Ladder I think of a rear suspension lateral locating link for a Sprint car or Dirt modified stock car as it allows the rear end to go thru its full suspension travel without any side to side movement unlike its Panhard bar counterpart.

darryl
11-29-2011, 08:46 PM
My first thoughts were sparks also, but then what you described reminded me of a geneva mechanism. Something rotates, then periodically advances another part of the mechanism. I'm also reminded of something I read in a popular science magazine (popular mechanics maybe) where a toy locomotive was made to run by vibrating a finger of sorts against a toothed wheel. In one direction of the vibrating finger the toothed wheel is advanced. In the other direction the finger drags back and is ready to push against a tooth again.

arcs_n_sparks
11-29-2011, 10:48 PM
When I see "Jacobs Ladder" I think of arcs n sparks. :)

I resemble that remark :D

JoeLee
11-29-2011, 11:01 PM
When I see "Jacobs Ladder" I think of arcs n sparks. :)
When I hear about a jacobs ladder I think of an old Frankenstein movie and the jacobs ladder I made when I was a kid from an old pair of rabbit ear antennas and a transformer from a neon beer sign.

JL................

Evan
11-30-2011, 12:26 AM
You need to post a picture or a drawing Brian. I can't picture what you have described in words without spending a long time building a mental picture.

v860rich
11-30-2011, 12:38 AM
When I think of Jacobs Ladder I think of a rear suspension lateral locating link for a Sprint car or Dirt modified stock car as it allows the rear end to go thru its full suspension travel without any side to side movement unlike its Panhard bar counterpart.

Exactly what I thought.

THANX RICH

People say I'm getting crankier as I get older. That's not it. I just find I enjoy annoying people a lot more now. Especially younger people!!!

Black Forest
11-30-2011, 12:58 AM
Does your Jacobs ladder need to have symetrical pipes to work? I was thinking of a way to feed one meter long pieces of firewood to a saw.

Lew Hartswick
11-30-2011, 08:47 AM
I'm with Evan on this, never heard of any other Jacobs Ladder.
This could turn into another "Johnson Bar" thread. :-)
...lew...

J.Ramsey
11-30-2011, 09:16 AM
I'm with Evan on this, never heard of any other Jacobs Ladder.
This could turn into another "Johnson Bar" thread. :-)
...lew...


http://www.spitzracing.com/index_files/Page724.htm

Tony
11-30-2011, 09:19 AM
correct me if I'm wrong but I think Brian is describing a type of walking beam conveyor.

hwingo
11-30-2011, 09:28 AM
I'm with Evan on this, never heard of any other Jacobs Ladder.
This could turn into another "Johnson Bar" thread. :-)
...lew...

When I think of Jacob's Ladder I think of three things taught to us during childhood:

1. Jacob's Ladder to heaven, described in the Book of Genesis (28:1019)

2. A "Blue Grass" song often sung during childhood and in later years

3. "Cup & Saucer", "Crow's Foot", and "Jacob's Ladder" all of which were made on our hands using a long piece of string.

Harold:)

JoeLee
11-30-2011, 10:55 AM
This is what I think of when you mention a jacobs ladder.

JL...................

http://www.youtube.com/watch?v=ZwJn_HqH2cc

rustamd
11-30-2011, 03:14 PM
You guys talking about something like this: http://www.youtube.com/watch?v=Ugwp4THEIo0 ?

Just very quick and not very good model, but I think it generally gets the concept thru, was at local factory awhile ago and they have system of these for feeding printing plates very gently.

brian Rupnow
11-30-2011, 08:23 PM
A teaser---Only had time for this much tonight. Have the mechanism to move the center staircase in mind, and if it works i should be able to animate it and post a video----
http://i307.photobucket.com/albums/nn294/BrianRupnow/ASSEMBLY-JACOBSLADDER.jpg

The Artful Bodger
11-30-2011, 09:03 PM
If you Google 'penguin toy' you will find a number of plastic toys where little plastic penguins climb a staircase then slide down to repeat. Quite cute to watch..
http://www.youtube.com/watch?v=iBa0k0Ogzh0

mister honey
11-30-2011, 10:58 PM
Brian,

Could you double up on the ladders so the orbiting motion lifts the balls up the ladder, and when the ladder is filled, an adjacent, mirror image ladder mechanism lifts the balls down?

I'm visualizing something like a triangle or A-frame construction.

Mike

Evan
11-30-2011, 11:32 PM
I've seen a very similar mechanism somewhere before a very long time ago. It was in a very small form and was horizontal. The motion of alternate rows of blades with serrations similar to the staircase was used to slowly move something along. For some reason that is all I can remember.

The Artful Bodger
12-01-2011, 12:08 AM
I've seen a very similar mechanism somewhere before a very long time ago. It was in a very small form and was horizontal. The motion of alternate rows of blades with serrations similar to the staircase was used to slowly move something along. For some reason that is all I can remember.


They were used in old grain harvesting machinery.

Evan
12-01-2011, 12:24 AM
I have been looking into this and that seems to be a possible origin of the name "Jacob's Ladder". That name it appears is a generic name for any sort of seed, feed, grain etc elevating equipment regardless of whether it uses scoops, bins or belts. It does not however apply to an auger. A likely reason for the use of the term "Ladder" is from nautical terminology. Grain handling equipment is of course very common at docks and ships do not have stairs, they have ladders.

I suspect somebody named Jacob had something to do with inventing something in this respect. There are many companies that are named Jacob's Something or Other including one that makes grain handling equipment but they don't seem to be old enough.

The Artful Bodger
12-01-2011, 12:28 AM
I have been looking into this and that seems to be a possible origin of the name "Jacob's Ladder". .

According the Wiki it comes from the Book of Genesis.

Evan
12-01-2011, 12:31 AM
I didn't think that company was old enough.

The Artful Bodger
12-01-2011, 12:35 AM
The straw elevator on some of the stationary grain threshing machines had wooden battons (about 2"x2") on simple multi throw cranks, each batton had metal spike like short nails the full length. The spiked battons moved in a manner similiar to the pieces in the penguin toy and moved the straw to the top of the straw stack.

I have also seen this basic mechanism on wool scouring machines where they solved the problem that is the curse of designers of such machines and that is the tendency (one could almost say determination') of wool fibres to wrap themselves around any revolving shaft.

Evan
12-01-2011, 01:47 AM
Try drilling through felt someday. :(

The Artful Bodger
12-01-2011, 02:35 AM
Try drilling through felt someday. :(

Thats what wad punches, and red hot pokers, were invented for!;)

Tel
12-01-2011, 05:21 AM
When you first mentioned this over on t'other side Brian, I had something a bit more vertical in mind which would (I think) be a bit easier.

Abner
12-01-2011, 07:17 AM
Jacobs ladder - I built one once. 10,000 v transformer from a neon beer sign and a couple of brass welding rods. zzzzzzzzzzzzzzzzzzzzap

laddy
12-01-2011, 08:06 AM
Back in the 1950's the chinese had a wooden toy hand held called the jacobs ladder. I still have it, fun to watch.

SmoggyTurnip
12-01-2011, 12:19 PM
When I think of Jacob's ladder I think of the ladder that my friend Jacob owns.

HWooldridge
12-01-2011, 04:54 PM
This mechanism is used in rolling mills and bar straightener shops to move bars along in a sideways motion. For example, we buy 12' bars for our CNC lathes that are straightened from coil. The bars are rolled through the dies, cut off and accumulated in a bundle. The accumulator uses this type of "creeper foot" to move them.

rustamd
12-01-2011, 05:01 PM
And engineer I know says back in a day they were called creep conveyors, however online search doesnt turn up much, just few somewhat relative matches.

Also I "think" i saw bar loader somewhere that this this mechanism in down feeding motion for like 1/2" 48" bar stock

Tony
12-01-2011, 05:05 PM
search for "walking beam conveyor"
http://www.youtube.com/watch?v=dHaICrGYWxQ&feature=related

aboard_epsilon
12-01-2011, 05:08 PM
Try drilling through felt someday. :(

you wet it ..and freeze it .

all the best.markj

brian Rupnow
12-01-2011, 06:26 PM
This is it, and it works really well, just as I had imagined it would. The two orange colored arms must rotate in tandem to give the desired effect, and though I can drag it around on my model, I can't quite figure out how to mate the two orange arms so that they continuously rotate in tandem. (My software is capable of doing it, its just that I don't know how to do it untill I've talked to my Solidworks service provider. I thought it would be the "Gear Mate" function, but it doesn't want to work for me tonight.) In real life, the two arms would have to be on a pair of sprockets connected with a small roller chain. Once I get the mate thing figured out, I will be able to animate it and make a short video of it operating.
http://i307.photobucket.com/albums/nn294/BrianRupnow/ASSEMBLY-JACOBSLADDER-1.jpg

brian Rupnow
12-02-2011, 07:05 PM
This is it---Very short and a bit too fast, but it lets you see what happens.
http://i307.photobucket.com/albums/nn294/BrianRupnow/th_JACOBSLADDERVIDEO.jpg (http://s307.photobucket.com/albums/nn294/BrianRupnow/?action=view&current=JACOBSLADDERVIDEO.mp4)

aostling
12-02-2011, 11:31 PM
This is it---Very short and a bit too fast, but it lets you see what happens.


Now the words in your OP make sense.

Something like this could make a novel escalator, at an airport say. You would need a parallel array of movable steps sandwiched between the stationary steps – but if the plates were about a quarter inch thick shoes would stay level, avoiding twisted ankles. It would be a strangely undulating way of getting between floors. Quite a trip!

Isn't something like this used on a sewing machine, to move the fabric underneath the reciprocating needle?

boslab
12-03-2011, 01:03 AM
heres a nice little one;
http://www.youtube.com/watch?v=GxoHjppFEg8
think the first jacobs ladder was in the cornish tin mines[ the name that is apart from the Bible], the mill engine lift shaft had steps on it and the men used this as a ascent/decent method by stepping on and off the rungs as they went up and down, at least this is what i was told, the name probably got used there first too as they were quite a religious lot, seems plausible
http://stjustvingoe.tripod.com/cornish_man_engine.htm
mark

brian Rupnow
12-03-2011, 08:46 AM
There are "Walking Beam" conveyors, and "Rocking Beam" steam engines. I think that quite often people confuse the two terms, as I see many references to "Walking Beam" steam engines.---Brian

EddyCurr
12-03-2011, 12:55 PM
In real life, the two arms would have to be on a pair of sprockets connected
with a small roller chain.Joining the two cam arms with a chain seems redundant, they are already
linked together by the center step section.

Just drive one cam ?

.

Toolguy
12-03-2011, 01:25 PM
With the cam pivots attached to the bar, if you drive one, the other will follow only if the bar is kept in a parallel attitude by some other type of guide. What about making the cams 2 sided and putting a short bar on the side opposite the stair bar? That should create a parallelogram that would keep everything in synch without a chain and sprockets. Then you could drive just one cam and be OK.

brian Rupnow
12-03-2011, 01:52 PM
With the cam pivots attached to the bar, if you drive one, the other will follow only if the bar is kept in a parallel attitude by some other type of guide. What about making the cams 2 sided and putting a short bar on the side opposite the stair bar? That should create a parallelogram that would keep everything in synch without a chain and sprockets. Then you could drive just one cam and be OK.
That would work, but an arm on the opposite side would then foul the driving shaft. You would have to drive the cam with a friction wheel.

brian Rupnow
12-03-2011, 01:55 PM
Joining the two cam arms with a chain seems redundant, they are already
linked together by the center step section.

Just drive one cam ?

.
Eddy--that only works if you have a flywheel on the second cam----Otherwise, when the driving cam goes over top dead center, the driven cam stops and tries to rotate backwards, locking everything up. Try it with a couple of cardboard discs and a connecing link cut from cardboard, with thumbtacks as pivots, and you'll see what I mean.

EddyCurr
12-03-2011, 02:22 PM
With the cam pivots attached to the bar, if you drive one, the other
will follow only if the bar is kept in a parallel attitude by some other type
of guide.With the center/axial pivots of the cam arms swinging from a common mount
and the outboard pivots attached to a common link, I believe a parallelogram
is formed.


Eddy--that only works if you have a flywheel on the second cam ... Try it
with a couple of cardboard discs and a connecing link cut from cardboard,
with thumbtacks as pivots ...I used wooden skewers in lieu of t-tacks. I noted the phenomenon you
describe but attributed this to poor tolerances, lack of rigidity and friction
occuring in the model.

How does the drive mechanism of a steam locomotive overcome the issue
when starting from rest where counter-weights would seem to have little
influence?

Edit: Brian, please consider this a rhetorical question. One that I'll puzzle out
myself. Don't let your progress get bogged down by my enquiry ...

.

brian Rupnow
12-03-2011, 07:33 PM
With the center/axial pivots of the cam arms swinging from a common mount
and the outboard pivots attached to a common link, I believe a parallelogram
is formed.

I used wooden skewers in lieu of t-tacks. I noted the phenomenon you
describe but attributed this to poor tolerances, lack of rigidity and friction
occuring in the model.

How does the drive mechanism of a steam locomotive overcome the issue
when starting from rest where counter-weights would seem to have little
influence?

Edit: Brian, please consider this a rhetorical question. One that I'll puzzle out
myself. Don't let your progress get bogged down by my enquiry ...

.
Eddy---I'm not a railroad engine specialist---but--I have asked the same question many years ago about how does the engineer know if the train will move or not when he opens the steam valve. You see, in a single cylinder engine, if the piston is exactly at top dead center or bottom dead center, the engine will not move when you open the steam valve. It will just set there untill you flick the flywheel to start the engine turning. The answer is very simple---The train has two cylinders, one on each side, and the crank throws are 90 degrees out of phase. The cylinders are double acting, which means that when steam is applied, one of the two cylinders will always be at a position other than at top or bottom dead center, which starts the train moving without having to give it a push to start the engine revolving. I think that somewhere in there is the answer to your question---It can't lock up, because there is always an alternating torque being applied to the axles, from one side or the other.--That, plus the fact that the inertia caused by the initial foreward movement of the train acts as a flywheel to get the non driven wheel "over the hump" and keep it rotating in the correct direction. The issue you have demonstrated is not a matter of "out of tolerance" caused by cardboard and thumbtacks. It would have exactly the same results even if it was made from steel and machined to very fine tolerances.

Evan
12-04-2011, 02:34 AM
Here is a SketchUp animation of the type of conveyor that I was thinking of. Low quality to minimize bandwith but it should be apparent how it works.

http://www.youtube.com/watch?v=mUYmp6OfDLw

Tel
12-04-2011, 03:32 AM
Have you a scale in mind Brian? Wot size of marble/bearing f'rinstance? Seems to me that the design is doing to be greatly dependent on knowing that.

Meanwhile, I'm thinking two identical gears, fitted with crankpins and with an idler gear between 'em. Should look pretty busy as well, especially if the gears are crossed out (spoked).

Peter.
12-04-2011, 04:05 AM
oops - edit turned into a new post :(

Peter.
12-04-2011, 04:07 AM
With the center/axial pivots of the cam arms swinging from a common mount
and the outboard pivots attached to a common link, I believe a parallelogram
is formed.

I used wooden skewers in lieu of t-tacks. I noted the phenomenon you
describe but attributed this to poor tolerances, lack of rigidity and friction
occuring in the model.

How does the drive mechanism of a steam locomotive overcome the issue
when starting from rest where counter-weights would seem to have little
influence?

Edit: Brian, please consider this a rhetorical question. One that I'll puzzle out
myself. Don't let your progress get bogged down by my enquiry ...

.

You cure the problem by adding a third cam and connecting the three

EddyCurr
12-04-2011, 07:24 AM
The answer is very simple---The train has two cylinders, one on each side,
and the crank throws are 90 degrees out of phase.Thank you.

Is a chain essential or would a flat/round section band provide sufficent
drive force?

If so, then instead lobes, perhaps using disks for cams - joined with a drive
band mounted on their circumferences - might meet requirements while
making for a simpler, lighter assembly ? If the mechanism is exposed, then
the disks could be decorated with patterns, even spokes, for esthetics.

http://i307.photobucket.com/albums/nn294/BrianRupnow/ASSEMBLY-JACOBSLADDER-1.jpg

.

John Stevenson
12-04-2011, 07:31 AM
I've seen a very similar mechanism somewhere before a very long time ago. It was in a very small form and was horizontal. The motion of alternate rows of blades with serrations similar to the staircase was used to slowly move something along. For some reason that is all I can remember.

They are on the base of nearly every sewing machine ever made.

Evan
12-04-2011, 08:37 AM
Yes, that was mentioned. I have seen it in some other large scale application.

brian Rupnow
12-04-2011, 08:46 AM
Yes, that was mentioned. I have seen it in some other large scale application.
And if I am correct, the ones on a sewing machine are called a "Walking foot".

brian Rupnow
12-04-2011, 08:48 AM
Eddy---simple bands won't work, because they would allow the two pulleys to get out of synchronization. Has to be either a roller chain or a belt with cogged teeth which mesh with teeth on the pulleys.

brian Rupnow
12-04-2011, 09:19 AM
I went over to Barrie's hobby shop on Saturday morning, hoping to find a small roller chain and sprocket set-up. Sadly, they don't have anything like that. I know from when I built the pile-driver, that the only sprockets available to me in town are small bicycle sprockets, and thats just too big for this project. I'm not sure what to do now. This would have made a nice small project with a lot of eye appeal and not too many parts, but as of now I'm kind of stuck!!!

Evan
12-04-2011, 09:25 AM
Use bead chain. It is readily available in different sizes. Bead chain pulleys are easy to make too. Also, you will find them in many types of curtain and blinds pulls.

You don't even need to draw it. It's been done for you.

http://www.thingiverse.com/thing:3147

Weston Bye
12-04-2011, 09:33 AM
I've not heard of similar examples of Brian's design referred to as a Jacobs Ladder, but don't remember what they were called.

Here's my own walking beam. Two axes of motion from a single cam. I suppose I could have worked something like Brian's design onto the back side of the works, replacing the lifter. (the lifter being the equivalent of one stage of Brian's design) Indeed, I thought of it, but ran out of time for NAMES and publication.

http://www.youtube.com/watch?v=35xw8G1_SCo&NR=1&feature=endscreen

More views:
http://www.youtube.com/watch?NR=1&feature=endscreen&v=FXT55RToB_Q
http://www.youtube.com/watch?NR=1&feature=endscreen&v=afRGJS8Qw-k
http://www.youtube.com/watch?v=EDqrzhqBFOU

brian Rupnow
12-04-2011, 09:43 AM
Very good, Weston. That is a great example of the classic "walking beam" type of conveyor, mechanically driven. I have designed much heavier ones driven by tandem hydraulic cylinders for conveying Caterpillar deisel engine cylinder heads through a bank of machining operations. One set of cylinders provided the lift, a second set provided the horizontal movement.

aboard_epsilon
12-04-2011, 10:10 AM
Dakota Freds new wash plant comes to mind

all the best.markj

Duffy
12-04-2011, 10:30 AM
Brian, rather than either bead or roller chain, why not use ladder chain? It would certainly be in keeping with the design concept, (a la manure spreader table drive!:D ) Most important, if you are interested, I have some chain and some 16-tooth and 32-tooth sprokets that I can spare. It was used to drive chart rolls in old elecro-mechanical recorders-surely you remember them! PM me.

brian Rupnow
12-04-2011, 10:51 AM
Duffy---That would work, but I would need both sprockets to be the same size. If you have two of the 32 tooth sprockets and enough chain to go around the sprockets setting at 3 1/16" center to center,name your price. What do you do for a master link? (What diameter o.d. are the sprockets.) We will name this mechanism the "Duffy" in your honour!!!

Black Forest
12-04-2011, 12:02 PM
Brian if the chain he is talking about is the same as what is on a manure spreader they don't have or need a master link. All you do is slide each link on to the next at an angle and they self lock.

brian Rupnow
12-04-2011, 01:47 PM
The model engine Gods have smiled on me once again!!! A gentleman known as Duffy out of Quebec has offered to send me a pair of sprockets and some chain out of a 1950's era printer. So---The project still lives, and will be christened "THE DUFFY" in his honour.

Evan
12-04-2011, 01:53 PM
Gerry ("Duffy") has some nice bits and pieces. He sent me a motor that is now the focusing motor in my 10" telescope. Now, if he would please send me some good weather for observing I would be even happier. :D

brian Rupnow
12-05-2011, 08:20 PM
This gets more and more interesting as I dig my way into the design. I realized last night that I didn't need to have the center flight of stairs extend down below the two outer staircases. I can achieve the same "orbiting" by moving the axis of the pivot arms up and into the position shown. This makes a much more compact assembly, easier to fabricate and much more eye appealing. The pivot arms clear the spacers between the two outer flights, and the bearing support off to one side clears everything. Now with sprockets to tie the two shafts together, and a pulley on the end of the highest shaft we are starting to get somewhere.
http://i307.photobucket.com/albums/nn294/BrianRupnow/ASSEMBLY-JACOBSLADDER-2.jpg

Evan
12-05-2011, 08:51 PM
Using cams inside round holes in the part is even more compact. Also, the cams are round (washers?) and there is just one shaft per cam.

http://ixian.ca/pics9/cam.gif

It also means that the outer steps need no opening and there is no need for the block that carries the shafts as the shafts can be carried in holes in the outer steps.

aostling
12-05-2011, 11:35 PM
Using cams inside round holes in the part is even more compact. Also, the cams are round (washers?) and there is just one shaft per cam.


This is very clever the compaction is complete.

Using eccentrics, as you propose, instead of cranks also allows making the pitch of the steps arbitrarily small. In fact, I wonder if this might be the mechanism for the "walking feet" on a sewing machine.

Tel
12-06-2011, 06:22 AM
Not only more compact Brian, but the centre flight will be much better supported that way as well.

Had a little play around this morning and I have come to the conclusion that the centre flight would be easier to do with two thinnish plates, with spacers between 'em.

brian Rupnow
12-06-2011, 08:54 AM
Thank you everyone for the great suggestions. I really like Evans cam concept. I'm not going to use it, but it is a really great idea. I have rethought the big "windows" in the sides of the outer staircases, in favour of two 2" dia holes in the near side staircase only for the "arms". I have added in a 4 1/4" dia pulley, which is as large as I can go without hiding some of the stair treads with it. I have added a 2 1/2" x 1/2" x 10" baseplate. I have to sneak Duffys sprockets and chain in behind that pulley yet. I also have to figure out some way to make a track for the wooden balls to follow around from the top discharge point to the bottom step to let them recirculate. My current thinking is two bent 3/16" rods running side by side to form a "ball track".
http://i307.photobucket.com/albums/nn294/BrianRupnow/ASSEMBLY-JACOBSLADDER-2-1.jpg
http://i307.photobucket.com/albums/nn294/BrianRupnow/ASSEMBLY-JACOBSLADDER-2-2.jpg

Evan
12-06-2011, 09:00 AM
It's also possible to run the mechanism with just one crank or cam along with a pantograph linkage supporting the moving steps.

brian Rupnow
12-06-2011, 05:15 PM
The ball return has me somewhat concerned. I don't want the model to take up a lot of real estate, so big sweeping curves of parallel round rod is not a particularly great option. Although the total drop is not dimensioned on the drawing, its only about a 4 1/2" total drop from the top step to the bottom step. I would like the balls to fall off the end of the top step, circle around a full 360 degrees and enter at the front of the bottom step. The best alternate I can think of at the moment is to have a short vertical section of 1" thinwall tube about 2 1/2" long on the left-hand side of the stairs, which the ball falls straight down through, but then I'm not sure what to do with it after it falls down thru the tube. I can't afford to have any level spots in the return system---it must all slope downhill. This kind of thing does not lend itself to a "machining" solution. Its a problem.---I can get my balls up, but I' not sure how to get them down!!!:eek: :eek: :eek:

Toolguy
12-06-2011, 05:32 PM
Maybe you could have the balls drop off the top step sideways into a straight tube or chute attached to the far side of the steps, go down to the bottom and back onto the first step. The top of the chute could be a little below the top step and the bottom could be a little above the bottom step, maybe with a rubber bumper at the bottom to soften the impact. That way gravity would feed it in and out of the chute. It would be a very compact setup.
Alternately you could make another set of stairs next to the first and step them down the same way they went up.

brian Rupnow
12-06-2011, 05:38 PM
Maybe you could have the balls drop off the top step sideways into a straight tube or chute attached to the far side of the steps, go down to the bottom and back onto the first step. The top of the chute could be a little below the top step and the bottom could be a little above the bottom step, maybe with a rubber bumper at the bottom to soften the impact. That way gravity would feed it in and out of the chute. It would be a very compact setup.
Alternately you could make another set of stairs next to the first and step them down the same way they went up.
Toolguy--I thought of your first concept, and am still considering it. However, your second concept carries far more work than I want to do.---Brian

Weston Bye
12-06-2011, 05:39 PM
Long after I completed my walking beam (post #58) I pondered the same conundrum. I thought about dropping the ball down, to be lifted with a mechanism similar to Brian's.

I've seen various tight-spiral wire ramps that could be used to feed a final linear piece with a j-hook on the end to return to the bottom of the ladder.

brian Rupnow
12-06-2011, 05:47 PM
I'm liking the idea of a vertical tube as stated earlier, then a parallel track made of round rods with only a slight downhill slope and a 180 degree turn at the discharge end. I have to be carefull that the balls don't bounce off the track or roll so fast that centifugal force causes them to jump off the rails. Thats why I was thinking of dropping them down a section of tube, to get rid of most of the vertical difference. A peice of 1" clear rigid plexi tube would be great for that.

brian Rupnow
12-06-2011, 05:49 PM
And where, short of making them myself, do I get a dozen 3/4" dia. wooden balls?????????

brian Rupnow
12-06-2011, 05:55 PM
Nevermind---I did a quick online search and found all kinds of sources. now what do I do with the other 88 wooden balls????
http://www.woodparts.ca/WOODTURNINGS-BALL.HTML

Weston Bye
12-06-2011, 05:58 PM
http://www.mcmaster.com/#wood-balls/=f90cjr

Sorry you're in Canada. I will be placing an order in a few weeks, but don't know exactly when.

Edit: uh, never mind, your prices are better.

Evan
12-06-2011, 06:03 PM
If you use a stiff wire track with a pair of wires you can control the velocity by varying the spacing of the wires. The closer the wires are the faster the balls roll. As the wires are widened the effective diameter engaging the track decreases and the forward motion slows as the rotation rate increases to conserve momentum. This can be used to great advantage to control the rate of descent and also works around banked curves. It can even be used to make the balls roll uphill quite a distance. Widen the wires a bit more and the ball drops through.

brian Rupnow
12-06-2011, 06:30 PM
I may have part of the answer. Like many men my age I take a plethora of age related medications. Nothing serious, just old man stuff, arthritis etc. Anyways---the pill bottles are a clear plastic 1" in diameter x 3" long.--Might make the perfect vertical tube for the returning balls. As it is I currently use them to hold a wide assortment of small taps, dies, set screws, etc. in my little machine shop. Might as well use them on my toys too!!!

brian Rupnow
12-07-2011, 06:28 PM
Waiting for wife to get home from work, so figured I could fill in some time---
http://i307.photobucket.com/albums/nn294/BrianRupnow/BEARINGSUPPORT-2.jpg

brian Rupnow
12-07-2011, 07:20 PM
Wife's home, supper is et, Jeapardy is coming on.
http://i307.photobucket.com/albums/nn294/BrianRupnow/OUTERSTAIRCASE-2.jpg

brian Rupnow
12-07-2011, 08:08 PM
Somebody on the "other" website where I post asked how in Heck I was going to machine acute angles.---The following is my answer:
Kel--I thought of that myself----Thats why, in the upper right hand corner of the drawing, I make reference to "non critical" and "saw/filing". I don't really know of any other way myself. However, as long as both sets of outer stairs are identical, it won't be a real problem. There is plenty of "play" in the way this thing will work. I have my software drawing template set to 3 decimal places---This assumes that whoever has enough moxy to attempt making something like this will know which dimensions must be held to a high accuracy and which can be "close" and still function. For me to do it any other way creates too much hassle when creating the drawings. In a real world "work" situation, where accuracy costs $$$$ I would take the time to change the number of decimal places and implied accuracy.

camdigger
12-08-2011, 05:14 AM
Brian

A couple random (or not so) thoughts.

The plates can be made in identical pairs spaced with spacer blocks rather than being "handed". The spacer blocks will allow the balls to be handled by the pair of plates. This will allow the steps to be cut in matched pairs, or even all 4 at once in a stack on your mill. There is also no need to square off the back of the step. A radius left by an end mill will have no effect on function as long as it is small enough not to interfere with the ball surface.

I see little reason to saddle yourself with acute angles on the "stairsteps" Why not tilt the steps back a bit so the balls will roll to the back of the step?

My .02 TL
Cam

Circlip
12-08-2011, 05:43 AM
--------------------------------------------------------------------------------

Somebody on the "other" website where I post asked how in Heck I was going to machine acute angles.---

Surprisingly, no one on the other collective has heard of a Dovetail cutter, although cutting the steps at 90 Deg.and tilting the plates backwards as stated is all that's required.


Regards Ian.

Tel
12-08-2011, 02:55 PM
I did think, briefly, of a dovetail cutter Sir Clip, but rejected it on the grounds that it would need to be a very shallow one. And in any case, the workpiece would still need to be tilted, or machined 'side up' so its just as easy to use a conventional endmill and ignore the angle on the riser.

brian Rupnow
12-08-2011, 06:48 PM
Just a pair of quickies tonight, because I'm very tired.
http://i307.photobucket.com/albums/nn294/BrianRupnow/JACOBSLADDER-ECCENTRICARM.jpg
http://i307.photobucket.com/albums/nn294/BrianRupnow/JACOBSLADDERBASE.jpg

Tel
12-08-2011, 11:19 PM
Ya know, it just occurred to me - if the ball could trip a reversing mechanism on the top step it would climb back down again! :eek:

brian Rupnow
12-09-2011, 08:20 PM
Tonight I was going to post a drawing of the center section of stairs, but on closer examination I decided there is no way to build what I had designed, at least without going to a lot of grief. So---tomorrow I will experiment with the 5/8" dia ball nosed cutter I bought while building the popcorn engine, and depending on what results I get, will post a drawing "after the fact".
http://i307.photobucket.com/albums/nn294/BrianRupnow/CENTERSTAIRCASE-2.jpg

Tel
12-10-2011, 02:26 AM
I still reckon two thinish side plates with a series of spacers is the way to go.

brian Rupnow
12-10-2011, 02:15 PM
Let the games begin!!!! Went down to my favourite metal supplier and got all the plate to make the Jacobs Ladder for $5.00. thought I was really smart, so went up to Canadian tire and bought a 2" bi-metal hole saw and an arbor for it. All the money I gained on the price of aluminum was soon lost at canadian Tire-----the holesaw cost $18.99 and the friggin' arbor cost $28.99. Oh well, what the heck, I'm working every day, earning real money.
http://i307.photobucket.com/albums/nn294/BrianRupnow/MATERIALFORJACOBSLADDER001.jpg

brian Rupnow
12-10-2011, 02:16 PM
First step--Print out center staircase at 1:1 scale, cut it out, glue it to poster cardboard. I don't usually recomend doing this, but on a part where the only two critical things are the hole centers, it is perfectly acceptable.
http://i307.photobucket.com/albums/nn294/BrianRupnow/papertemplate001.jpg

brian Rupnow
12-10-2011, 02:17 PM
Cut out cardboard, tape it firmly to the peice of aluminum to be cut, which has been coated with Dykem, and scribe around it. if the pattern has two "square" edges, take time to align them with the edges of the aluminum before taping it in place.
http://i307.photobucket.com/albums/nn294/BrianRupnow/scribedaluminum001.jpg
http://i307.photobucket.com/albums/nn294/BrianRupnow/scribedaluminum002.jpg

brian Rupnow
12-10-2011, 02:18 PM
Go nuts with bandsaw----
http://i307.photobucket.com/albums/nn294/BrianRupnow/bandsawcenterstaircase001.jpg

brian Rupnow
12-10-2011, 02:18 PM
Well. that seemed to work out very well.
http://i307.photobucket.com/albums/nn294/BrianRupnow/machiningcenterstairs002.jpg
http://i307.photobucket.com/albums/nn294/BrianRupnow/machiningcenterstairs001.jpg

brian Rupnow
12-10-2011, 02:19 PM
This is one of those times when I absolutely can not afford to have the center axis of the holes to be out of square with the staircase, causing it to "orbit". I don't really trust my "Tilt a whirl" vice, because the moving jaw kicks up a bit when it is tightened. When its critical, as in this case, I clamp the part being drilled to the table with a couple of 1/2" square unground lath tools for stand-offs so as not to drill into the mill table. I am going to use 5/16" shoulder bolts to connect the center staircase to the eliptical arms. This will mean that regardless of what it says in the drawing of the outer staircases, they will both need a pair of 2" diameter holes in them---To clear the rotating eliptical arms on one side and to clear the heads of the shoulder bolts on the other side.
http://i307.photobucket.com/albums/nn294/BrianRupnow/drillingcenterstaircase001.jpg

brian Rupnow
12-10-2011, 02:19 PM
Well there!!! Thats my Saturday morning accounted for. Hope the outer staircases go as well.
http://i307.photobucket.com/albums/nn294/BrianRupnow/finishedcenterstaircase002.jpg

The Artful Bodger
12-10-2011, 02:48 PM
I had the pleasure earlier this week of visiting a shop where a man is making horse shoes on a machine he designed and built himself. Round steel stock is feed in one end and horse shoes drop out the other, one ever 12 seconds or so.

His machine uses mechanisms much like being described here.

davidwdyer
12-10-2011, 04:45 PM
Uh hummm. It looks like you're supporting your piece with lathe bits.

It could be just fine, but I discovered that mine were not nearly as exact in measurements as I thought they were.

brian Rupnow
12-10-2011, 05:01 PM
And more of the same---Only this time its the outer staircases. No words of wisdom to offer up here, except that you'll notice I did screw the two peices of plate together BEFORE sawing them out, to keep them exactly the same.
http://i307.photobucket.com/albums/nn294/BrianRupnow/OUTERSTAIRCASESCUTOUT001.jpg

brian Rupnow
12-10-2011, 05:02 PM
Uh hummm. It looks like you're supporting your piece with lathe bits.

It could be just fine, but I discovered that mine were not nearly as exact in measurements as I thought they were.
I have checked mine, and the accuracy and sameness of the four that I use is far greater than my own capabilities as a machinist.:eek: :eek:

Lew Hartswick
12-10-2011, 07:13 PM
All the ones I've checked AREN'T square. :-) the differences in the two
directions was as much as 10 thou. Don't remember the exact numbers
any more.
...lew...

brian Rupnow
12-10-2011, 09:06 PM
Well---I'm impressed!!!! The holesaw works great. I did this out on my big old 16 speed drill press in my main garage. The little mill I've got starts popping fuses at anything bigger than a 1/2" drill, and those tiny glassfuses are over $3.00 each. This has been a good days progress.
http://i307.photobucket.com/albums/nn294/BrianRupnow/outerstaircaseholes002.jpg
http://i307.photobucket.com/albums/nn294/BrianRupnow/outerstaircaseholes001.jpg

brian Rupnow
12-11-2011, 08:37 AM
Now that I know my method works, I feel safe posting the drawing.
http://i307.photobucket.com/albums/nn294/BrianRupnow/CENTERSTAIRCASE-2-1.jpg

brian Rupnow
12-11-2011, 11:53 AM
Lew Hartwick just emailed me and asked if I owned stock in the layout dye company, and made me laugh.---Reminds me of a very funny story. The year I was 17 an older fellow in my small town asked me if I would paint his mothers house white for $100 if he supplied the paint. It was a small house, and I really needed the money so I said yes. The son lived out of town a few miles, but he had to drive in and out of town twice a day, and his mothers house was right on the main corner in town, so every time he came in or out of town he would see me there painting. Now I have to admit, I had never painted a house before, but it was an old previously unpainted clapboard house, and it sucked up paint like a sponge. I think I painted that damn house about 4 times before it quit soaking up paint. I didn't want to waste any good clothes, so I just wore the same old clothes for a week straight through, and by the time I was done, everything I was wearing was painted white, including my old work shoes and my hair. Finally I was finished, and Rene' came to inspect the job. He walked all around, looked up, down, and in all the crooks and crannies, pulled out a $100 bill (The first one I had ever seen), and pronounced it a job well done.--Then he asked me--"By the way, how did that paint taste?" somewhat taken aback, I asked what he meant. He said---The first dozen times I drove by the house, I thought you were using a brush, but the last dozen times I drove by, it looked like maybe you were drinking the paint and p1ssing it on!!!!:eek: :eek: :eek:

brian Rupnow
12-11-2011, 03:21 PM
2 drawings to finish off the weekend. I have all my platework finished except for these two pieces.
http://i307.photobucket.com/albums/nn294/BrianRupnow/SPACER-2.jpg
http://i307.photobucket.com/albums/nn294/BrianRupnow/SPACER-1.jpg

brian Rupnow
12-11-2011, 03:31 PM
As in all the things I design, there is a bit of"design evolution" happening here. Basically, I decided to put the 2" dia holes in both outer staircases, and the counterbored holes will be in the "near side" outer staircase only, with clearance holes in the spacers and threaded #5-40 holes in the far side staircase only. This is because I had to thread them anyway to bolt the two sections of outer stairs together while sawing them out and shaping them. I will update the outer staircase drawing later this week.
http://i307.photobucket.com/albums/nn294/BrianRupnow/finishedplatework001.jpg

brian Rupnow
12-11-2011, 06:45 PM
Gotta make a note to myself---Maybe paste it on my forehead!!! Don't push so damn hard on the scriber. I like my scribed lines to show up really good, so I push really hard on the scriber to make the lines really visible against the Dykem layout dye background. Then after all the layout dye is washed off with methyl alcohol, I have these big deep grooves to sand/polish out, and it takes forever. Maybe if I post about it, I'll remember for next time-----

Tel
12-11-2011, 10:34 PM
:D I have a habit of that as well, and it seems to get worse as the eyes get older!

Black Forest
12-12-2011, 02:08 AM
First it is not the eyes going bad. What happens when you get older is your arms shorten up considerably.

Brian I am really looking forward to you having this project up and running. I have a couple of idea's regarding something for cutting firewood.

aostling
12-12-2011, 05:39 AM
I have a couple of idea's regarding something for cutting firewood.

The chunks in a German woodpile are all the same length, to a tight tolerance. I will be interested in seeing how a Jacob's Ladder helps you with that.

Black Forest
12-12-2011, 07:34 AM
Actually they are! Most are within 2cm of the same length. What I am thinking is a way to feed a double blade circular saw. We normally cut the 1 meter pieces into three parts. The Jacobs ladder would feed a revolving spoked double wheel that would actually hold the wood as it gets pushed through the two saws. I envision a chain conveyor feeding the jacobs ladder up to the saws. The sawn pieces fall down onto another conveyer to load the finished pieces into whatever you want.

I have seen these double blade saws in use. The problem is one person has to load the revolving wheels that feed the saws. I want to be able to sit in my excavator and load the trailer with the meter piece bundles. I would have a remote to kill the saw if something got jammed.

brian Rupnow
12-12-2011, 06:55 PM
Drilling the spacers for between the outer staircases.---Ya gotta love those little machinists jacks. I didn't even know there was such things till heard about them on this forum.
http://i307.photobucket.com/albums/nn294/BrianRupnow/drillingspacers001.jpg

brian Rupnow
12-12-2011, 07:33 PM
Time for a teaser shot.---Its a trick. Those are 1" balls, not 3/4". but you get the idea. I didn't have any 5/8" plate to make the bearing stand with, so I used a piece of reclained 1/2" plate----thats why there is an extra hole in the plate. i will probably make up a 1/16" spacer to set between it and the staircase it is bolted to.
http://i307.photobucket.com/albums/nn294/BrianRupnow/ballsonstaircase001.jpg

brian Rupnow
12-12-2011, 08:34 PM
The center section of staircase was heavier than I felt comfortable with, so a series of 1" dia. holes took away some of the weight.
http://i307.photobucket.com/albums/nn294/BrianRupnow/lighteningholes001.jpg

sasquatch
12-12-2011, 08:47 PM
Interesting project to follow Brian, thanks for posting the procedures and great pics.

brian Rupnow
12-13-2011, 08:33 PM
It makes me so happy when one of my projects gets mature enough to stand up all by itself!!! (Man, I've been around my latest grand kid too much!) Got the baseplate finished tonight and the spacer that fits in behind the bearing stand. Next thing to tackle will be the eliptical arms I guess, then I can't do much untill Duffys sprockets show up in my mailbox.
http://i307.photobucket.com/albums/nn294/BrianRupnow/standingonitsown003.jpg
http://i307.photobucket.com/albums/nn294/BrianRupnow/standingonitsown002.jpg

brian Rupnow
12-14-2011, 08:25 PM
WOOHOO!!!!! Duffys sprockets arrived in the mail today. Thank you Duffy!!! Thank you, thank you, thank you!!! I made up the two eccentric arms tonight from brass and "posed" them with the sprockets and chain for tonights picture. I will model the sprockets and add them into my assembly, and figure out my shafts next. The sprocket bores were just slightly undersize from .1875, and I suspect that in their previous lives were press fitted onto 3/16" diameter shafts. Duffy said they are out of a 1950's era printer, so I doubt they were metric. I put them in my lathe and ran a 3/16" reamer thru the bores, and will add a #5-40 set screw to each hub. Since the original plan was to have 5/16" shafts, and thats what my eccentric arms and bearings are set up for, I may put a 5/16" bore in the 4 1/2" drive pulley and mount the sprockets outboard of the pulley.---I'll have to model it up and see what it looks like. I don't dare open the sprocket bores out to 5/16" as they are two piece construction and would fall apart if I took that much out of them.
http://i307.photobucket.com/albums/nn294/BrianRupnow/ECCENTRICARMSANDSPROCKETS001.jpg

brian Rupnow
12-14-2011, 08:50 PM
Naw, It'd just look too goofy with the sprockets outside the pulley. I'll make the pulley with a 3/16" bore and set it up like this.
http://i307.photobucket.com/albums/nn294/BrianRupnow/ASSEMBLY-JACOBSLADDER-2WITHSPROCKETS.jpg

Lew Hartswick
12-14-2011, 09:54 PM
I just thought of something: !!!!
This "thing" should not be called a "ladder", it's an "escalator". The
steps move, ladders the "rungs" are fixed. :-)
See what happens when I start to "think". :-)
...lew...

aostling
12-14-2011, 11:03 PM
This "thing" should not be called a "ladder", it's an "escalator".

At last, my suggestion (reply#38) has a convert. A bizarre escalator, but might be kind of fun.

Duffy
12-14-2011, 11:03 PM
Brian, silver solder the sprocket bosses and THEN bore them out 5/16".

brian Rupnow
12-15-2011, 08:11 AM
I was haunted by my old friend insomnia last night, so I popped out of bed at some ungodly hour this morning and bored one of the sprockets out to 1/4" with no consequent disasters. I'll use that one on the upper shaft so I can keep the pulley bore at 1/4". The one on the bottom shaft can stay at 3/16" bore, because there is not nearly so much overhung load on the shaft.

brian Rupnow
12-16-2011, 05:20 PM
No post last night, as I had a "command appearance" at number 1 Grand daughters Christmas concert. I did however find a source for 3/4" diameter wooden hardwood balls in Guelph, Ontario, and was able to buy 12 balls for $12. I also ordered a pair of 5/16" dia. x 1/2" long shoulder bolts which will be used to hold the center (moving) staircase to the eccentric arms. Tomorrow morning I hope to finish the shafts, and may even get to test run this critter!!!----Brian

brian Rupnow
12-16-2011, 09:00 PM
Cowabunga Roy!!! I think its going to work!!! I held the chain tight by hand and rotated it thru one complete revolution, and it seems to do exactly what I expected it to. I'm going to have to do some serious shortening of the chain, and I will probably have to but a 'take-up' idler on it to keep any slack out of the chain, but I think its going to be great. I couldn't wait 4 days for my shoulder bolts to come in, so I made up my own for "try-out' purposes. If I find time tomorrow. I'll make up a pulley and shorten up the chain, and MAYBE we'll get a first run video made up. I will only be able to use "pretend" balls, and like migrating lemmings, they will all jump off the cliff into the sea because I don't have my return ramp made up yet, but I'm feeling good about the progress.
http://i307.photobucket.com/albums/nn294/BrianRupnow/firstassembly002-2.jpg
http://i307.photobucket.com/albums/nn294/BrianRupnow/firstassembly001-2.jpg

sasquatch
12-16-2011, 09:44 PM
Looks good Brian, i can sense the excitement building in your'e post!!!:D

Yup,, we're lookin forward to seeing a video of it workin, GREAT!!!!!!!!!!!

brian Rupnow
12-17-2011, 08:31 AM
This morning I'm making a 4" dia. pulley, because thats the largest stock I have. However, I have found a real "caveat" in my design. Even with Duffys chain connecting the two shafts, unless it is pulled painfully tight, the non driven shaft still wants to turn and rotate the wrong direction when the driven shaft passes over "top dead center". I hadn't realy expected this. I think I see a way to add a second "link" between the two shafts, offset the same amount as my eccentric arms, but out of phase to them by 90 degrees, on the outside of the pulley. If that is the case, Duffys chain may become redundant. I'm learning as I go along here, so will keep you posted.----Brian

Rosco-P
12-17-2011, 09:06 AM
Just like this child"s toy: http://toygalaxy.net/plpera.html

Duffy
12-17-2011, 10:16 AM
Brian, how about an idler sprocket on a torsion spring? It would ensure no slack in the chain drive. Yes, I DO have a third, but then the cupboard is bare!

brian Rupnow
12-17-2011, 10:32 AM
Rosco--Jeez, if I had known I cold buy one, I wouldn't have had to build it!!!:eek: :eek: ---Duffy-If i need a tension idler I'll just build one from brass---it won't need teeth.

brian Rupnow
12-17-2011, 10:39 AM
I built a pulley this morning, and here you can see that the center staircase had paused halfway thru its "lift" mode and lifted one of the 1" balls up, getting ready to carry it up to the next step. I'm still not 100% sure that this will work with only a chain and not a second link arm, but I bet I'll know before the weekend is over. Gotta go now and take a load of dry firewoood over to a friends house. I just got a gas fireplace in last week, and its wonderfull.--
http://i307.photobucket.com/albums/nn294/BrianRupnow/pulleyonjacobsladder001.jpg

Stepside
12-17-2011, 11:00 AM
Brian

I have some "one way bearings" but they are for 1/8 inch shaft. The good news is that such a thing exists. The bad news is I don't have the box or the part number or the source. They are quite small so I could mail you a couple.

Some of the parts in your "ladder" are perfect for a 3D printer. I am going to share this thread with some tech teachers that have the printers.

Keep up the "series".

Pete

brian Rupnow
12-17-2011, 04:01 PM
Brian

I have some "one way bearings" but they are for 1/8 inch shaft. The good news is that such a thing exists. The bad news is I don't have the box or the part number or the source. They are quite small so I could mail you a couple.

Some of the parts in your "ladder" are perfect for a 3D printer. I am going to share this thread with some tech teachers that have the printers.

Keep up the "series".

Pete
Stepside--I know about one way bearings, and they do work very good. I hadn't thought of using them in an application like this, but they might work. However, I'm a long way from crying "yield" on my current application. Another thought is a spur gear on each shaft and one idler gear in the middle meshing with each shaft gear to keep everything "timed" properly. The nice thing about a project like this is all the "solutions" that percolate to the surface.

The Artful Bodger
12-17-2011, 04:36 PM
Brian, all the walking beam elevators I have seen (two or three in a lifetime!:) ) Have had more than one beam and they were out of phase. I know Bently made a car engine with eccentric drive to the overhead cam and that used double eccentrics.

Maybe you can weight one of the shafts so that gravity takes it past the point of uncertainty?:rolleyes:

Stepside
12-17-2011, 04:53 PM
Brian
Okay so I lied a bit. I do have a part number Torrington DF-53460. It also says ROYCO 46. No number on the outside of box, but a number on the cellophane packets. Another solution would be a miniature timing belt system with a tensioning wheel.
Now I am toying with the idea of building it 1/2 sized.

Pete

aboard_epsilon
12-17-2011, 05:10 PM
what sort of chain is that ..looks like meccano chain ..

they have the stuff for sale on ebay in the uk ..but its bloody expensive

i have all some special sprockets for driving it ..sort of doubled up ones that grip between the links not through them .....or am i remembering the Panza chain from down the coal mines ...will have a look tomorrow

the chain

http://www.nzmeccano.com/94.php

all the best.markj

brian Rupnow
12-17-2011, 05:20 PM
Stepside--For the smaller, Elmer Verbourg sized engines, I think about half scale to what I have would be perfect.

Lew Hartswick
12-17-2011, 05:30 PM
Brian, all the walking beam elevators I have seen (two or three in a lifetime!:) ) Have had more than one beam and they were out of phase. I know Bently made a car engine with eccentric drive to the overhead cam and that used double eccentrics.

My NSU Sport Prinz had such a drive to the cam also. I "Think" it had
3 arms but it's been close to 50 years since I had it.
...lew...

brian Rupnow
12-17-2011, 08:32 PM
I am really surprised about the "delicacy" of timing between the two shafts. Even the slightest bit of slack in the chain, and the non-driven shaft wants to flip around and travel backwards, locking up the mechanism. Tomorrow morning I am going to but an outboard link between the two shafts 90 degrees out of phase with the center staircase. That will absolutely keep things from getting "out of time",and may do away with the necessity of having a chain and sprockets. I am learning new stuff here. In 46 years of designing just about every conceivable type of industrial machinery, I haven't ran across something quite like this. It is reminding me more and more of the solid links between drive wheels and non drive wheels on steam trains. John Bogstandard tried to explain this to me in a much earlier post, but I didn't understand what he was getting at, however it is becoming clearer as I progress.

brian Rupnow
12-18-2011, 01:17 PM
Well, at this point in the game, all I have to report is a complete and total FAIL!!!!! I got up early this morning and made the modifications to add a second arm on the outside of the pulley. I even took the inner staircase, the bearing support, and the added link which all have to have identical hole centers and put dowels through all 3 at the same time to convince myself that I hadn't machined something wrong. The net result of adding the second link was that it locked things up tighter than ever. I am somewhat bumfoozeled at this point, so will take a break from this and read for the afternoon. My next plan is to remove the second link, go back to the chain and sprockets, and open the lower hole in the staircase out to .030 oversize. Maybe if I engineer a bit of "float" into the system it won't lock up like it currently does when all the holes are a "reamed fit"
http://i307.photobucket.com/albums/nn294/BrianRupnow/fail001.jpg

camdigger
12-18-2011, 02:14 PM
Brian

As has been mentioned before, a modified version of this was used in conventional grain harvesting combines in the back and were called the "straw walkers". I don't remember both ends being driven. Both ends had similar cranks, but I only recall the front crank being driven. On the older machines, the crank bearings were simple wooden blocks, so precision definitely wasn't a priority. I don't recall ever having heard of a problem in that area on 30 year old machines...

I have seen a similar linkage used in rope makers to drive 2 of three links from a single driven one. Having attempted one, I know they are quite tricky get to move. The old rope maker had the 3 shafts arranged with the CL of the shafts at the points of an equilateral triangle.

Don't give up hope now....
Cam

brian Rupnow
12-18-2011, 02:33 PM
I'm going to make this statement while firmly grasping my wooden chair, but the oversize hole in one end of the staircase SEEMS to have gotten rid of the bind. I think that with a swing arm chain tensioner, the problem may be solved.

The Artful Bodger
12-18-2011, 02:43 PM
Brian, there were a number walker beams in threshing machines.

In your machine, I suggest the second link would work best at 90 degrees phase angle and I am sure a bit of 'float' would be an advantage.

John

Clark
12-18-2011, 04:55 PM
My father showed me how to make a Jacob's Ladder 50 years ago with Model T spark coil and the transformer to my electric train.

Black Forest
12-19-2011, 03:45 PM
Brian here is a possible solution for the return of the balls.
http://www.youtube.com/watch?NR=1&feature=endscreen&v=ydZViLLIrX4

brian Rupnow
12-19-2011, 05:45 PM
Bruce---Cool video!!!

brian Rupnow
12-19-2011, 06:07 PM
It works!!!!---BUT---The trick is going to be slowing it down enough. I had a 1.5" pulley on the mill to test drive it with, and the moving center staircase wanted to run at warp speed. I kept putting the 1" steel ball on it and then slowly advancing the mill speed from zero to see it elevate the ball. The device wouldn't run at all, then would take off and bounce that friggin steel bearing ball around like a ping pong ball. I didn't have my chain tensioner on a spring loaded swing arm, just had it bolted onto the bearing support, but that isn't going to do it. The sprockets are not perfectly concentric to the hub bores, and the load imposed by the center staircase varies quite a bit through its 360 degrees of travel, causing the chain to "whip" and jump sprocket teeth, which of course threw things out of time and caused it to lock up repeatedly. At any rate, it works. all I have to do is slow it down a lot.
http://i307.photobucket.com/albums/nn294/BrianRupnow/itworks001.jpg

brian Rupnow
12-19-2011, 06:12 PM
And I know how I'm going to do it. In the foreground of the attached picture is the pump that I built a couple of years ago, and I am going to reclaim the timing belt pulley from it. In the background is a gear reducer system that I had on the Doodlebug, which has the mating timing pulley on it, as well as a pair of nylon meshing gears. I am going to "reclaim" these components and build them into the Jacobs Ladder, to get it running at a more manageable speed.
http://i307.photobucket.com/albums/nn294/BrianRupnow/slowdown001.jpg

brian Rupnow
12-19-2011, 08:09 PM
My dozen wooden balls showed up in the mail today. Good quality and a very fast turn around. In spite of all the crude remarks that I thought of before posting this picture, I'm going to be the good clean living boy my 91 year old mother expects me to be and say nothing, just post the picture.
http://i307.photobucket.com/albums/nn294/BrianRupnow/woodenballs001.jpg

sasquatch
12-19-2011, 08:31 PM
re: The good clean living boy:


THANK GOODNESS!!!!!!!!!!!!!!!!!!!!!!!!


That,s all we need during the approaching festive season,,,, is a man cursing at his balls!!!!!!!!!!!!!!!!!!!!:confused: :D

Stepside
12-19-2011, 08:41 PM
Brian
Pinocchio and his 5 brothers must have a bit of extra room in their shorts after your purchase.

Actually have you considered a long spring as the return chute for the balls? Something with a slightly larger ID than the OD of the balls?

brian Rupnow
12-22-2011, 07:49 PM
I was right at the point of giving up on this project. It kept locking up, the balls kept falling off when they were almost to the top----it was ugly!!! I was setting here thinking "What haven't I tried, that might have some positive effect on the way things worked." The only obvious thing was to try the pulley on the lower shaft, so just for a giggle, I did.---and EUREKA!!!! It made a big difference in smoothness of operation and how the balls stayed on the operating ladder. With all the gears, timing belts, etcetera, it is starting to take on a Rube Goldberg/Steampunk appearance, and I like that!!! Time is at a premium right now, but once we get thru christmas I will be hooking this up to my overcrank single engine and beginning to take a serious look at a ball return. Merry Christmas everyone, thanks for looking.---Brian
http://i307.photobucket.com/albums/nn294/BrianRupnow/Rube001.jpg

brian Rupnow
12-23-2011, 04:17 PM
Here we are guys. Large as life and twice as ugly!!! First succesful run!!!
http://i307.photobucket.com/albums/nn294/BrianRupnow/th_JACOBSLADDERMOVIE-1.jpg (http://s307.photobucket.com/albums/nn294/BrianRupnow/?action=view&current=JACOBSLADDERMOVIE-1.mp4)

sasquatch
12-23-2011, 04:46 PM
Brian, thanks for posting this, very interesting !!

Never seen one of these before so been following your'e build project, now-

How fast will this normally run ??

brian Rupnow
12-23-2011, 04:54 PM
Brian, thanks for posting this, very interesting !!

Never seen one of these before so been following your'e build project, now-

How fast will this normally run ??

Sasquatch---Good question. I have seen similar designed equipment in industrial settings deliver a part to the top of the staircase about every 10 to 12 seconds. Of course this was dependent on the machining cycle time of the part that was being delivered. The ladder in itself is only a material handling device. I think mine will run roughly 2 to 3 times faster than what you seen in the video. I haven't "stop watched" mine so I don't really know. This will be driven with one of my model steam engines, and they seem to work most efficiently at about 400 to 600 RPM. I just watched the video and counted---1-Mediteranean-2 mediteranean-3 mediteranean---Seems to be currently running at about 4 to 5 seconds for a full cycle from one step up to the next.

camdigger
12-23-2011, 08:10 PM
Looks good Brian!:cool:

Just a thought, but you're going to need some deep reduction to get the drive speed low enough. Maybe the crazy clockwork mechanism, would drive this as a deep reduction gear box??? Be a real Rube G device then...:D

Bill736
12-24-2011, 08:38 PM
When I think of Jacobs Ladder I think of a rear suspension lateral locating link for a Sprint car or Dirt modified stock car as it allows the rear end to go thru its full suspension travel without any side to side movement unlike its Panhard bar counterpart.

That's also called a Watts Linkage, isn't it ? ( yes, I'm off subject, but sometimes I can't resist.)

brian Rupnow
12-25-2011, 09:42 AM
That's also called a Watts Linkage, isn't it ? ( yes, I'm off subject, but sometimes I can't resist.)
Yes, you are correct--sort of. A Panhard linkage stretches from the frame on one side across to the rear axle housing on the other side, or at least to the center. A Watts linkage has a pivotting member on the center of the rear axle with a link reaching from the pivotting member out to the frame on each side.

brian Rupnow
12-26-2011, 05:56 PM
Christmas is over, all the relatives have returned home, and I got to play in my shop a bit this afternon. The Jacobs ladder runs successfuly when driven by my "Overcrank Single" air/steam engine. I however, am having a very difficult time getting am "in focus" movie of it. My camera instructions say to hold the button half way down to let the auto focus work before pushing it all the way down to take a picture. That seems to work fine for still shots, but doesn't seem to work worth a darn when I'm making a video. I will talk to the Cannon camera people when the holidays are over and get that sorted out. I may try the Jacobs Ladder with my horizontal twin engine tomorrow and see if the action smooths out any--its a bit jerky when driven by the Overcrank Single. At any tate, another milestone has been reached, as I now know that one of my air/steam engines has enough power to run things.
http://i307.photobucket.com/albums/nn294/BrianRupnow/stillshotwithovercrank001.jpg
http://i307.photobucket.com/albums/nn294/BrianRupnow/th_JACOBSLADDERWITHOVERCRANKSINGLE.jpg (http://s307.photobucket.com/albums/nn294/BrianRupnow/?action=view&current=JACOBSLADDERWITHOVERCRANKSINGLE.mp4)

sasquatch
12-26-2011, 06:08 PM
Well that is GOOD news, step by step, your'e getting the bugs out!!

Looking forward to a clear version of a video run.


Now, How about posting a pic here of that sweet liitle yellow pickup for those here that haven,t seen it?

brian Rupnow
12-26-2011, 07:24 PM
Jeez Sasquatch---I thought everybody had seen this, at least some version of it. I've been into hotrod building and drag racing all my life. I built this about 7 years ago and it is my daily driver from May to October. Its a 1931 Ford model A roadster pickup with small block Chevy power. The cab and box are steel and the fenders are fiberglass.---Brian
http://i307.photobucket.com/albums/nn294/BrianRupnow/IMG_1527.jpg

sasquatch
12-26-2011, 08:59 PM
Thanks Brian ,, COOL RIDE!!

brian Rupnow
12-27-2011, 01:57 PM
Success!!! I have figured out the mystery of my camera (Read the instruction booklet) and changed engine over to my Horizontal Twin to run the Jacobs ladder. Its working real slick now. And yes, you will hear me contradict myself---I can't honestly remember if it was 3 or 4 years ago that I built my horizontal twin engine---(I say both in the video). Now I can start work on my ball return track.
http://i307.photobucket.com/albums/nn294/BrianRupnow/th_JACOBSLADDERWITHTWINHORIZONTAL.jpg (http://s307.photobucket.com/albums/nn294/BrianRupnow/?action=view&current=JACOBSLADDERWITHTWINHORIZONTAL.mp4)

lynnl
12-27-2011, 03:06 PM
Good job Brian!
I'd not been following along on this, so just now finishing reading all the entries from the first post.
Very entertaining.

That's a good looking soup can too! :D

brian Rupnow
12-30-2011, 09:45 AM
Slowly, and not too surely, my ball return is progressing. I'm making it up as I go along here, but this first leg of the return track seems to work okay.---At least any balls dropped in at the top end do fall cleanly and quickly out through the hole in the side. ;D ;D
http://i307.photobucket.com/albums/nn294/BrianRupnow/BALLRETURN-1001.jpg

brian Rupnow
12-30-2011, 02:31 PM
Its not very often that I think I'd like a power feed on my mill table, but it would have been nice to have one today!!! I'm building the second part of my return ball track, and that slot is about 10" long x 1/4" deep x 3/4" wide. I feed .030" on the vertical axis bfore each cut, and deepen it another .030" when I reverse directions, so I'm cutting while travelling both ways. With a 3/8" end mill, daamn, thats a lot of cranking!!!!
http://i307.photobucket.com/albums/nn294/BrianRupnow/BALLTRAKONMILL001.jpg

Duffy
12-30-2011, 02:39 PM
Brian, in aluminum with a 3/8" bit, it is almost a no-brainer-use your cordless drill! But FIRST mount the mill in a collet. please.

brian Rupnow
12-30-2011, 04:59 PM
Rotary tables are a GOOD thing to have!!!!
http://i307.photobucket.com/albums/nn294/BrianRupnow/balltrak2androtarytable003.jpg

brian Rupnow
12-30-2011, 05:01 PM
And yes, the ball does return all the way to the first step!!! Now, to build a few brackets to hang my ramp on-----
http://i307.photobucket.com/albums/nn294/BrianRupnow/balltrak2androtarytable005.jpg

sasquatch
12-30-2011, 05:50 PM
lookin good Brian!!!!!!!!!!!!!!!!!!!!!!!

A great way to bring in the "NEW YEAR"!!!!!!!!!!

Congratulations!!!!!!!!!!!!!!!!!!!

brian Rupnow
12-30-2011, 06:34 PM
Brian, in aluminum with a 3/8" bit, it is almost a no-brainer-use your cordless drill! But FIRST mount the mill in a collet. please.
Duffy---I know that you are correct about mounting the cutter in a collet. However, just the way these small mills are made, if you don't mount the cutter in a chuck, the head gets in the way and its very difficult to see what you are doing. I find that holding the cutter in my chuck works okay for aluminum, but I wouldn't use it that way for milling steel. ---Brian

brian Rupnow
01-01-2012, 01:57 PM
YES!!!! Old age and treachery triumph once again!!!! The balls go up, the balls roll down, all that remains to be done is a good video. Just when I thought I was all finished, the balls proceeded to roll down the ramp so damned fast that they "Jumped the track" at the bottom curve just like the freight train in the old movies. However, a bit of a retaining wall on the bottom curve, and all was well.----Video to foollow----After I've had my afternoon nap.
http://i307.photobucket.com/albums/nn294/BrianRupnow/FINISHED002-4.jpg
http://i307.photobucket.com/albums/nn294/BrianRupnow/FINISHED003-2.jpg

sasquatch
01-01-2012, 02:08 PM
Re:" After having my afternoon nap",,,,,

Brian that is a common thing amongst us old lads, not because we're slowing down or anything,:rolleyes: it,s just because we take our time to plan things out first.:D

Lookin forward to the video, again CONGRATS !!

brian Rupnow
01-01-2012, 04:14 PM
http://i307.photobucket.com/albums/nn294/BrianRupnow/th_JACOBSLADDERFINISHEDVIDEO.jpg (http://s307.photobucket.com/albums/nn294/BrianRupnow/?action=view&current=JACOBSLADDERFINISHEDVIDEO.mp4)

brian Rupnow
01-02-2012, 05:23 PM
Nothing new on the machinery itself, but I have been playing with my cameara today, to see why I get such beautiful still shots but such marginal results with videos. Finally resorted to "Restore Defaults" because it yielded such great results when I bought it new. This seems to have greatly improved the video function, so I may well have unknowingly changed a setting on the camera at some point while using it. At any rate, here is a much clearer video.----Brian
http://i307.photobucket.com/albums/nn294/BrianRupnow/th_JACOB-TAKE-2.jpg (http://s307.photobucket.com/albums/nn294/BrianRupnow/?action=view&current=JACOB-TAKE-2.mp4)

dockrat
01-02-2012, 06:12 PM
Brian, for some reason neither of those last two videos will load for me. I have had no trouble with any of the others. Your just having way too much fun with your projects. Keep it up. I love following you as you work your way through them.

sasquatch
01-02-2012, 06:25 PM
Brian, the video worked fine for me, great video and project, love the little clickety sounds of the engine running!!

dockrat
01-02-2012, 06:38 PM
Got it now Brian. Had to close and reopen my browser for some reason. That thing works like a damn!!!!

DFMiller
01-02-2012, 07:01 PM
Brina,
That turned out way too cool.
Thanks for the posts and the video.
Dave

sasquatch
01-02-2012, 07:04 PM
"brina"?????:d :d :d