Patio's projects

The Photo Album is a place for "Shop Shots" as well as pictures and descriptions of projects that we are working on. Show off your Shops, Machines, and your Projects!

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John Hasler
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Re: Patio's projects

Post by John Hasler » Sun Feb 25, 2018 5:55 pm

I've had pretty good luck with flat belts salvaged out of junk printers and such without buying special pulleys.

That looks like a lot of O-ring for the job.

Patio
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Joined: Wed Oct 06, 2010 3:14 pm
Location: Centralia Wa

Re: Patio's projects

Post by Patio » Tue Mar 27, 2018 1:13 am

I did increase the depth of the grooves, and it made a big difference in the friction on the O-ring. Thanks everyone for the suggestions!


Things don't always work out the way one plans. Such it the case with the control mechanism that I had drawn and built. It won't fit in the space with the proper orientation to the lever, that will actuate the movement.
Soooo... I have changed the design. I have just got it drawn and will have to do some more measuring of the space it has to fit in, to make sure it will work. Either way, I am learning to draw with Fusion 360.
Here it is.
The shaft is a press fit on the red pinion gear. It is a slip fit on both of the gold vertical supports and the purple arm. The grey cylinder on the end of purple arm will be a bearing to capture the rack (the gray bar). The purple arm and the rack can rotate around the axis of the pinion gear. The green linkage will connect to the movable arm on the lathe and move the rack up and down. The Blue bar is for mounting the assembly to the lathe. The blue bar, on top, the gold vertical supports and the potentiometer, are all in fixed positions, everything else moves, or pivots.
I hope that makes some sense!?
Cazeneuve speed control with rocking rack B.jpg
Cazenuve speed contorl with rocking rack A.jpg
It is not complete by any means. I will need to thicken the upper parts of the vertical supports to accept fasteners. There are a couple of washers and a c-clip that are not in the drawing also. It is just as far as I have gotten tonight.
More to come as I get it done! :)
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Patio
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Location: Centralia Wa

Re: Patio's projects

Post by Patio » Fri Apr 06, 2018 9:53 pm

More drawings of the speed control mechanism.
Assembly v22.jpg
It is much smaller now, about 2" in width. I am going to make some more changes tonight. Mostly to the mounting brackets.
I have removed the actual linkages from the lathe, took some pictures, imported them into F360, and scaled them to proper dimensions. From there I was able to make 3D drawings. I am now going to assemble the whole thing in F360 and animate them to function as they would when installed. This will help me to understand any clearance issues with other parts and the mounting brackets.

This is the linkage set up. The pin on the end, at the top, is a fixed position on the lathe. The square hole with the pin in it, on the bottom linkage, is where the square rod, that runs through the apron and has the speed control lever, connects to and drives the movement of the system. The hole midway up the vertical link is where I will connect the rack gear of the mechanism. I hope this makes sense!?
control linkage v6.jpg
The picture of the linkages.
20180405_124107a.jpg
Tonight I am going to try to get it all assemble in the program.
If I am able to display a animated version when completed, I will. I do not know if the program will let me do that, yet.
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Patio
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Location: Centralia Wa

Re: Patio's projects

Post by Patio » Sun Apr 08, 2018 3:10 am

I have a fully functioning model! :D
Here are pictures of it, in the maximum and minimum positions.
A new Assembly v8.png
A new Assembly v8a.jpg
I have not modeled the mounting plate, yet.
My only concern at this moment is, if the Rack gear will bind, against the pin, of the (Blue) rotating assembly, that captures the Rack gear. I may make a simple, wooden/cardboard, model to test this.
A new Assembly v11.jpg
Now to create all the drawings with dimensions, so I can make the parts.
I have learned an awful lot about modeling and joints, in Fusion 360, over the last week.
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Harold_V
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Re: Patio's projects

Post by Harold_V » Sun Apr 08, 2018 4:19 am

Looking good. If it was up to me, I'd likely use a small bearing, not a pin, against the rack. I have several and will drop one off the next time I'm in town if you think you'd like to go that way. I think they're a perfect size. You could make the fit adjustable if necessary.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

Patio
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Location: Centralia Wa

Re: Patio's projects

Post by Patio » Sun Apr 08, 2018 12:40 pm

The design included a bearing, originally. It seemed to jam in the simulation also, so I thought I would make the radius smaller, by using a pin, to see if the forces would be at a better angle allow better rotation of the keeper. This why I think building a prototype might be useful.
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John Hasler
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Re: Patio's projects

Post by John Hasler » Sun Apr 08, 2018 12:59 pm

Very nice, but if I understand what you are doing correctly I'd suggest a stringpot design rather than a rack and pinion.

https://en.wikipedia.org/wiki/String_potentiometer

Patio
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Location: Centralia Wa

Re: Patio's projects

Post by Patio » Sun Apr 08, 2018 5:13 pm

John, thanks for the suggestion. I will have to look into that, it might be a bit easier to implement, than the one I have designed.

In the mean time. Here is a video of the prototype, I made today, to test the concept.
https://youtu.be/wZ_ueIBusRw
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John Hasler
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Re: Patio's projects

Post by John Hasler » Sun Apr 08, 2018 5:49 pm

The one you've designed is cool, though. I didn't really understand how it worked until I saw the video.

Patio
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Location: Centralia Wa

Re: Patio's projects

Post by Patio » Tue Apr 10, 2018 1:12 am

Hi John, I ordered some 32 pitch/14.5 pressure angle, steel rack and plastic gears today for just under 30 bucks. I did not look at the string pots until this evening, and found them to be quite costly, but I still like the concept, and it may solve some issues I may have.
Soooo I may have to see if I can figure out how to make one, to turn the pot about 300 degrees.
I'll be back! :)
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John Hasler
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Re: Patio's projects

Post by John Hasler » Tue Apr 10, 2018 8:02 am

> Soooo I may have to see if I can figure out how to make one, to turn the pot about 300 degrees.

That's what I meant, of course. I would never suggest that you buy anything you could make. A servo pot would work best but an ordinary linear one will do.

Patio
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Location: Centralia Wa

Re: Patio's projects

Post by Patio » Fri Apr 13, 2018 6:58 pm

Here is the latest design. I think this may work better that all the others. It has taken awhile to get to this point, but I have learned a lot along the way. More about modeling in Fusion360 than anything.
Sting and Rack with linkage.jpg
It is a combination of all the previous designs I have made.
John mention of a "String Pot", is what led me in this direction. Thanks John.
I think this may solve many issues.
This design give me all the travel I will need. It works in such a way that setting the spindle speed to 0, will be a pulling motion on the string and rack, (Better Safety).
It will make aligning with the levers, and connection of the mechanism to the levers much easier. I may even use a magnet to connect the string to the levers, until I know where I need it to be.
I am going to make the bottom pulley bracket and mounting bracket first. This will reveal any other issues I may have, before I make all the other parts. The pulley bracket is about 14" long.
More to come, as I get it done! Thanks for all the comments.
Live for the moment!
Prepare for tomorrow!
Forgive the past!

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