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Re: What's On My Bench: Two videos

Craig
 

Thanks for those videos Jim.

Two Tier #1 has inspired me to look at motors that I can use for long running of my own work. Which brand/type of motors would you recommend?

Surfer #1 - this brought a smile to my face. I particularly liked the use of magnets in the feet to allow them to slide. Brilliant thinking!

Best wishes,
Craig


Re: Teddy the Artist

Craig
 

The box cam looks interesting, but I don't think it's what's being used here. I have a photo of both sides of the elephant cam and it appears flat on both sides:





I'm still unsure whether it spins on the backing plate. It seems unlikely because the operation would then become more complicated for the user - having to switch off at exactly the right point so that the shape is in the correct orientation to allow removal from the slot.

I'm thinking along the lines of a planetary follower (if that's the correct term?) ie. stationary cam, moving follower - basically a disc (or arm) with centre of rotation being the central square hole in the template, with a sprung follower on a bell crank arm so that the pivot is not in line with the centre of rotation. Having the pivot not-in-line might help with ensuring the follower doesn't get 'trapped'? Still at the drawing board (no pun intended) stage.

It's getting to the stage where all I'm thinking about is elephants!!!

:-)

Craig


What's On My Bench: Two videos

 

In addition to my studio where all my tools are I have a desk where my computers are.  And this week I took the time to create two videos. The links will take you to the YouTube videos:
The video is captured with my Pixel 2 XL smartphone.  Editing is done in Kdenlive on my Windows 10 desktop PC.  I still struggle creating these clips.  There is so much to keep in mind.  
Enjoy your weekend.
Cheers
-Jim Coffee-
creating automata in San Diego, CA


Re: Teddy the Artist

 

I think that you would be correct if the shapes were simple...such as the oval.  These animal shapes, however, are complex, coming back on themselves.  Personally I don't see how the box cam could follow the shapes.
-Jim-

On Fri, 5 Jun 2020 at 19:27, Ron K via groups.io <peter.pilot=yahoo.com@groups.io> wrote:
Craig, I think I figured it out. Our stumbling is because we aren't shown the back side of the cam. The mechanism is called  box cam.
Similar to a pantogram, the follower is a pin in a groove.  Because the groove is smaller than the visible cam, the phantogram is probably close to or 1:1. The crayon / pen is free to move completely around the exterior of the cam. The square pin holds the cam firmly for the pin to ride in the groove.  

Thoughts?

Ron


Re: Teddy the Artist

Ron K
 

Craig, I think I figured it out. Our stumbling is because we aren't shown the back side of the cam. The mechanism is called  box cam.
Similar to a pantogram, the follower is a pin in a groove.  Because the groove is smaller than the visible cam, the phantogram is probably close to or 1:1. The crayon / pen is free to move completely around the exterior of the cam. The square pin holds the cam firmly for the pin to ride in the groove.  

Thoughts?

Ron


Re: Teddy the Artist

Ron K
 

Down the rabbit hole . . . found this note:
"The toy was available for only one year through the Sears Roebuck Christmas catalog. It originally sold for $3.98 without batteries."

https://www.grandoldtoys.com/toydb_Detail.php?id=526&S_keywords=japan,tin%20litho


Re: Teddy the Artist

 

This is an interesting thread.  How does this work?  I still don't know...been thinking a lot about it.
One of the things that I've surmised is that the little pattern 'does not' rotate.  Rather it is held properly orientated.  And something crawls around the inside or the outside and transfers the pattern...I still don't understand though.
Will be interesting to understand once someone comes across the solution.
-Jim Coffee
San Diego, CA

On Fri, 5 Jun 2020 at 01:46, Craig <craiglonghurst@...> wrote:
Thanks for all the great input.
 
Ron - "The Writer" genre is definitely a holy grail, but Teddy doesn't appear to share the same mechanisms. I would be very interested in seeing a YouTube clip with a similar mechanism if you can find it again.
 
Kim - Yes I know! I thought this would be simple. It's funny how enclosing a mechanism in a tin box can suddenly deepen the mystery!
 
Dominique - I like the idea of a magnetic follower, providing omnidirectional attraction (rather than a spring acting in a single direction). Would still get 'stuck' inside the shape of elephant's trunk though?
 
Randy - That is a great bit of kit. Also on my future builds list is an Arduino "Plot Clock"
 
Gus - I was thinking on a similar line re: pivot point and sliding follower. I thought I had something that would work with the duck shape but the same approach wouldn't work with the elephant's trunk unfortunately. Yes I've been looking through books of old mechanical toys and this appealed to me to have a go at building, because it looked 'simple' !!!.
 
Here are a couple of the metal templates and the outputs they produce (the size difference of external/internal curves indicates a roller follower):







And a photo of the underneath of Teddy with the plate removed (this was from an old ebay picture). Looks like a reduction drive from the motor onto a small worm gear. The large bar appears to be pivoted to give a vertical motion.



Craig


Re: Teddy the Artist

Craig
 

Thanks for all the great input.
 
Ron - "The Writer" genre is definitely a holy grail, but Teddy doesn't appear to share the same mechanisms. I would be very interested in seeing a YouTube clip with a similar mechanism if you can find it again.
 
Kim - Yes I know! I thought this would be simple. It's funny how enclosing a mechanism in a tin box can suddenly deepen the mystery!
 
Dominique - I like the idea of a magnetic follower, providing omnidirectional attraction (rather than a spring acting in a single direction). Would still get 'stuck' inside the shape of elephant's trunk though?
 
Randy - That is a great bit of kit. Also on my future builds list is an Arduino "Plot Clock"
 
Gus - I was thinking on a similar line re: pivot point and sliding follower. I thought I had something that would work with the duck shape but the same approach wouldn't work with the elephant's trunk unfortunately. Yes I've been looking through books of old mechanical toys and this appealed to me to have a go at building, because it looked 'simple' !!!.
 
Here are a couple of the metal templates and the outputs they produce (the size difference of external/internal curves indicates a roller follower):







And a photo of the underneath of Teddy with the plate removed (this was from an old ebay picture). Looks like a reduction drive from the motor onto a small worm gear. The large bar appears to be pivoted to give a vertical motion.



Craig


Re: Teddy the Artist

Gus
 

Hi Craig,

Maybe the arm which writes is pivoted at some point in relation to the pattern. It is able to slide through it back and forth, spring loaded in say the backward movement. The section of this arm may be  square, as would the pivot through which it slides, so staying upright. It might have as a follower and upturned, thin end, in contact with the revolving pattern, and  may have a roller tube spinning on it, acting as a bearing. The pattern turns, and may be spring loaded in the opposite direction so the "follower" never leaves the pattern irrespective of the direction of the shape being followed. The patterns are much smaller than the drawing it seems, so the relationship of the pivot determines the size of the drawing above. 
Are you considering making something like this ?

Gus


Re: Teddy the Artist

Randy
 

Here is a microprocessor driven drawing arm that can be programmed to draw most anything. 
image.png


Re: Teddy the Artist

Dominique Corbin
 

Kim i agree with you. For me the "cam follower" can be a little v-shaped pulley magnetized to "glue" to the iron animal! So when the pulley turn it follow the shape.


Re: Teddy the Artist

Kim
 

Yes, those outlines which go “backwards" make a simple cam follower impossible. I am just thinking out loud here, I don’t have a concrete solution, but how about something which “walks" along the perimeter of the plug-in shape. I could imagine a rubber coated, electrically driven axis which drives itself along the perimeter instead of simply being rotated, but again that very thin and comparatively sharp trunk of the elephant would be a real problem.

Something that they sold cheaply as a toy and we can’t work it out! Perhaps we need a 10 year old!

Kim :o)

Am 03.06.2020 um 14:45 schrieb Craig <craiglonghurst@...>:

Thanks Guys
 
All three of those are great but they all use abstract cams which are difficult to produce (although Shasha offers free software on his website for creating them).
 
Skrippy is very neat. However it is still effectively using two cams for x/y although he has combined them into each half of a single cam. Explained here: http://www.contraption-cart.com/blog/howmywritingautomatonworks 
 
I first came across a picture of Teddy the artist in the book on p20 of "Mechanical Toys" (Spilhaus). The author is not particulary complimentary saying it is "a very poor successor to the princely automata and fine mechanical artists of the past. It is merely a pantograph, reproducing the shape of a cam directly; the cam is nothing more complicated than a circle deformed into the outline of an animal. The ingenious double cam of the older toys, one swinging the pencil horizontally, the other vertically, was not employed"
 
However it is the simplicity of the simple animal shaped cam that I find most attractive.
 
I still can't work out how to design a follower that would cope those shapes - just look at the trunk of that elephant!

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Re: Teddy the Artist

Ron K
 

Craig, I didn't save the link, sorry, but I saw a YouTube with a Teddy like kit being built. Maybe that will offer some insight. 


Re: Teddy the Artist

Ron K
 

I can't think of a mechanical solution other than a cam, that The Writer/ the Hugo automata uses to write script, not simple, or a phantogram that is essentially a right angle cam follower. I suggest finding everything you can on The Writer/the automata used in Hugo, to see how the script and complex drawing with pen lifts was managed. Both of these used cams.

R


Re: Teddy the Artist

Craig
 

Thanks Guys
 
All three of those are great but they all use abstract cams which are difficult to produce (although Shasha offers free software on his website for creating them).
 
Skrippy is very neat. However it is still effectively using two cams for x/y although he has combined them into each half of a single cam. Explained here: http://www.contraption-cart.com/blog/howmywritingautomatonworks 
 
I first came across a picture of Teddy the artist in the book on p20 of "Mechanical Toys" (Spilhaus). The author is not particulary complimentary saying it is "a very poor successor to the princely automata and fine mechanical artists of the past. It is merely a pantograph, reproducing the shape of a cam directly; the cam is nothing more complicated than a circle deformed into the outline of an animal. The ingenious double cam of the older toys, one swinging the pencil horizontally, the other vertically, was not employed"
 
However it is the simplicity of the simple animal shaped cam that I find most attractive.
 
I still can't work out how to design a follower that would cope those shapes - just look at the trunk of that elephant!


Re: Teddy the Artist

 

Hi Craig and everyone...
This is a good thread.  The video's are certainly interesting.  I especially love The Writer (who wouldn't?).  I noticed The Writer doing something that I had not noticed before...the paper moves.  Each character is written in the same spot...the paper moves a character at a time.
The Writer is even more amazing to me when one considers when it was built.  No electricity.  No power drills or power lathes.  Pretty amazing.  Did one make his own screws and nuts and etc., or were there places to purchase things like that?  Was the metal already flat and ready to use...or did someone purchase ingots and make their own sheet.  And then on the other hand...in three hundred years people will look back on us.  I wonder what they will see and think about us?

I've sat here trying to imaging how Teddy the Artist works and I can't see it yet.  I'll dream about it tonight and perhaps something will come to me.  An interesting automata.
Thanks for this thread.
--
-Jim Coffee-
creating automata near San Diego, California
one of the group moderators
JamesCoffee.com


Re: Teddy the Artist

Ron K
 

Check out artist Aaron Kramer's drawing machine.  https://youtu.be/i-qRXYXaYyY and  Shasa Bolton's Skrippy. and anything you can find on Pierre Jaquet-Droz's The Write https://youtu.be/GoTMjKglusM

It might be worth investing in Shasa's Skrippy as something to experiment with. IIRC, he has some free profiles on his site.

I saw Aaron's work at the 2018 Automata con and what was cool to see was the large number of modifications to the cam, pieces of wood removed, added, and/or the profiles changed.

Ron


Re: Teddy the Artist

Craig
 

Thanks Kim. Yes the pantograph is a lovely linkage. I can't see how that would work with the intricacies (although pretty simple) of the templates supplied here as there is a lot of in/out movement required to trace the outline and I'd imagine a revolving centre sprung arm would get jammed.

I'm unsure whether the templates rotate (given that they have a square hole - possibly to engage a drive).

I'm sure it's such a simple mechanism that I'll kick myself.


Re: Teddy the Artist

Craig
 

Thanks Paul. Looks like I've got some thinking to do!


Re: Teddy the Artist

Kim
 

Hi Craig,

thanks for sharing that. It’s quite thought-provoking. As a child I was once given a pantograph to copy and scale up/down drawings. 

Wikipedia has a nice animation

Maybe that’s a starting point? You would need something to more around the push-in pattern, with a spring pushing it towards the centre. Then you would have to somehow fold the mechanism to make it as compact as the splendid “Teddy the artist”.

Good luck with your project!

Kim :o)



Am 02.06.2020 um 13:25 schrieb Craig Longhurst <craiglonghurst@...>:

Hi everyone,

I've always been fascinated by drawing/writing mechanisms and recently stumbled across "Teddy the Artist" made by Yonezawa: https://www.grandoldtoys.com/toydb_Detail.php?id=526

Videos in operation here: https://www.youtube.com/watch?v=brx47OS90CM and https://www.youtube.com/watch?v=xCU2rzAMC28 (quite a few more on youtube)

What I like about this is the apparent simplicity of the cam - being the same shape as the picture to be drawn. Having said that I still can't work out how to design a cam follower / pen attachment to achieve this.

Any ideas?

Craig