Author Topic: Auto reverse mechanism  (Read 3010 times)

Online Brian Rupnow

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Re: Auto reverse mechanism
« Reply #30 on: August 11, 2017, 10:26:54 PM »
Interesting!! A very nice do nothing machine... I love it!

Oh, I think you'll find that the o-ring isn't stretchy enough for that application... ????

Pete
Rubber O-rings are surprisingly stretchy. The travel on the reversing mechanism is fairly short, so I think the o-ring drive will stretch enough to accommodate it. if not I will put a spring loaded tension arm in there instead.

Offline 10KPete

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Re: Auto reverse mechanism
« Reply #31 on: August 12, 2017, 01:35:35 AM »
Well, in any case I know you'll figger out something, Brian. That's the neat thing about your threads; you reveal your thinking process as you go along. Very educational..

Pete
Craftsman, Tinkerer, Curious Person.
Retired, finally!

Online Brian Rupnow

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Re: Auto reverse mechanism
« Reply #32 on: August 12, 2017, 03:48:16 PM »
And here we are, the entire spur gear family all posing for a family photo.


Online Ye-Ole Steam Dude

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Re: Auto reverse mechanism
« Reply #33 on: August 12, 2017, 04:23:44 PM »

Beautiful work Brian and a very interesting thread.

Thomas

Online Brian Rupnow

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Re: Auto reverse mechanism
« Reply #34 on: August 13, 2017, 08:04:49 PM »
We have a finished and fully operational gear cluster. This didn't go quite as smoothly as I would have hoped. The chuck on my rotary table is attached with bolts in T slots, but no centering spigot. Sometimes, (I expect for sins I have committed in the distant past) the damned chuck moves a bit off center. It's not visible, but you can end up with slightly off-center gears. The pitch circle ends up being shifted very slightly from the bore. This of course results in gears that mesh very good on one side of their rotation, and are very very tight on the other side of their rotation. However, with a bit of fettling and cursing, everything now meshes very well, and I've done enough work for today.


Online Brian Rupnow

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Re: Auto reverse mechanism
« Reply #35 on: August 13, 2017, 10:11:20 PM »
Since I don't have room for a spring tension toggle device directly below the actuator arm because of the shaft running thru, then I will put a compression spring acting on it from above. This will serve as my toggle device.

Offline Art K

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Re: Auto reverse mechanism
« Reply #36 on: August 14, 2017, 12:30:54 AM »
Brian,
Just wanted to let you know that I am following along. You always come up with interesting gadgets for your engines to run.
Art
« Last Edit: August 15, 2017, 02:36:54 AM by Art K »

Online Brian Rupnow

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Re: Auto reverse mechanism
« Reply #37 on: August 14, 2017, 12:39:17 AM »
Thanks Art.  It gets harder and harder to come up with something different. I like something different like this, and I'm never absolutely sure whether it's going to work or not until I have finished it. I did make sure to select gear sizes that will work on model engines, so if the design is a total wash, at least I can reclaim them.---Brian

Online Ye-Ole Steam Dude

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Re: Auto reverse mechanism
« Reply #38 on: August 14, 2017, 01:25:37 AM »

Brian how are you holding the 3 brass gears on the shafts?

Thomas

Online Brian Rupnow

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Re: Auto reverse mechanism
« Reply #39 on: August 15, 2017, 12:29:47 AM »
After I got home from my "away office" this evening. I whittled out the "Pivot anchor plate". Got all of the holes drilled and reamed, and the profile roughed out. I will pick up the four ball bearings tomorrow.

Online Brian Rupnow

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Re: Auto reverse mechanism
« Reply #40 on: August 15, 2017, 01:08:46 AM »

Brian how are you holding the 3 brass gears on the shafts?

Thomas
The bore in the gears and backing plate is 0.344" diameter. The shafts are made from 3/8" material, turned down to 0.344" all except for a 1/16" long section at the end. The shaft is pushed thru the gear, thru the backing plate, and silver soldered. The 3/8" diameter head holds the gears on.

Online Brian Rupnow

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Re: Auto reverse mechanism
« Reply #41 on: August 16, 2017, 09:52:30 PM »
Today we have the four bearing mount shaft made and pressed into the aluminum backplate, with the bearings Loctited to the shafts. Why does one bearing have a blue grease seal while the other three are black? Beats me--Must be something to do with "diversity".

Online Brian Rupnow

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Re: Auto reverse mechanism
« Reply #42 on: August 18, 2017, 02:52:26 PM »
In the final phase of completing the gear cluster and "toggle" device, I decided it would be wise to make the compression of the toggle spring adjustable.

Online Brian Rupnow

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Re: Auto reverse mechanism
« Reply #43 on: August 18, 2017, 09:33:56 PM »
I've been a busy little beaver. The 6" diameter pulley is finished, and the toggle is finished. The toggle seems to work very well, and definitely will "kick" the gear mechanism down into position as soon as it is "over-centered" in either direction. Hopefully, tomorrow I will get the slotted track machined and attach the rack to it.---Brian

Online Brian Rupnow

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Re: Auto reverse mechanism
« Reply #44 on: August 19, 2017, 04:47:22 PM »
Today I have the first trial assembly of all the important pieces. Everything fits and clears properly, but I'm not getting enough "kick" from the toggle to shift things cleanly. I may mill some material away below the rack to let the rack set a little farther away from the gear cluster. This will allow for more movement when the gear cluster shifts position, and the toggle should have more movement so should be more effective.