Author Topic: Auto reverse mechanism  (Read 3227 times)

Online crueby

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Re: Auto reverse mechanism
« Reply #45 on: August 19, 2017, 10:30:45 PM »
Should be some way to make a clock pedulum out of that, 'tick' on the movement to one side, 'tock' on the movement to the other...

 :popcorn:

Offline Gas_mantle

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Re: Auto reverse mechanism
« Reply #46 on: August 20, 2017, 04:07:48 PM »
Looks like it's taking shape nicely :-)

I came across this reversing oddity by accident and wondered if it may interest you if you decided to have another go at something :-


Offline Brian Rupnow

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Re: Auto reverse mechanism
« Reply #47 on: August 20, 2017, 07:56:23 PM »
Well, I'm finished enough to begin having doubts about whether it will work or not. It works when I turn the pulley by hand and use my other hand at the end of stroke to help flip the toggle over. However, as I expected, the problem is going to be getting that toggle to flip over nicely and consistently. I've spent enough of this weekend working to get it done to this stage. I will play with it in the coming week to see if I can get the toggle to work better.

Offline BillTodd

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Re: Auto reverse mechanism
« Reply #48 on: August 20, 2017, 09:31:28 PM »
it might need springs on the ends of the buffers to ensure a clean switch

Bill
Bill
wy omnibus Latinis taurus stercore?

Offline Florian Eberhard

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Re: Auto reverse mechanism
« Reply #49 on: August 20, 2017, 09:46:02 PM »
Hey Brian

I like those mechanisms you are building, they (also if they are only on a sketch or so) always attracht my attention :)

I just wanted to write
maybe you need to gear up the flywheel so it turns with more rpm so you cet enough energy out of it at the end of the track
But after thinking again it doesnt seem to be the problem since you are driving the mechanism via the flywheel. I guess there is a state where both gears are not engaged and this is exactly where the whole thing comes to a stop?

I think then either Bill's Idea with the springs at each end could help or some kind of "lever" between the toggle spring and the toggle itself so the "machine" pushes over that kind of switch and only after that, the spring will force the toggle to change gears.

Acutally its the same as with the single cylinder steam feed pumps. They only work because there is the shuttle valve which switches over before the steam for the main cylinder is reversed to the other side and therefore the movement of the main cylinder stopped (which drives the first valve piston or c-valve).

If you have something that goes over the dead center before the driving force is cut off, then this should work better than it does right now.


Cheers Florian

Offline zeeprogrammer

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Re: Auto reverse mechanism
« Reply #50 on: August 20, 2017, 11:24:43 PM »
You'll get it Brian. No doubt.  :popcorn:

@Gas_mantle - cool video.
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you', whistles, and certain dinner bells.
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To work. To work. Zee-The Thread Trasher.

Offline paul gough

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Re: Auto reverse mechanism
« Reply #51 on: August 20, 2017, 11:36:24 PM »
Maybe having a look at, 'Ingenious Mechanisms, for designers and inventors' by Frankln D. Jones might help or extend your design as there are chapters on reversing mechanisms. It is a four volume work, might be in a library, but easily obtainable second hand, try Abebooks, should be pretty cheap in Nth America as it is a U.S. publication from Industrial Press. I have always enjoyed mechanical contrivances they seem to be as fascinating as watching monkeys. Regards Paul Gough.

Offline Brian Rupnow

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Re: Auto reverse mechanism
« Reply #52 on: August 21, 2017, 12:15:59 AM »
After playing with this thing for an hour after supper, it has loosened up considerably. I have come to the conclusion that I need a stronger spring and more hysteresis in my toggle. I'm sure that a lot of you old guys could use a bit more "hysteresis in your toggle", but that's not what I'm talking about. I can buy a stronger spring sometime this week, and I think that if I lower the rack by milling away about 0.100" of material below the rack, that will increase the "hysteresis". (Let the toggle move more between full left and full right position.)

Offline Noitoen

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Re: Auto reverse mechanism
« Reply #53 on: August 21, 2017, 11:24:00 AM »
Instead of a coil spring you could use a leaf spring. Look at the snap-action functioning of a microswitch to get the idea.

Offline BillTodd

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Re: Auto reverse mechanism
« Reply #54 on: August 21, 2017, 07:28:35 PM »
part of your problems could be the direct connection between the switch and the drive. i.e. as the gear drives toward the stop it is lifted out of the rack by the toggle .

if you look at a toggle switch (light switch) the operating lever can move with out the contacts moving until the spring is moved over centre.

if you adjusted your mechanism so that the stops moved the upper pivot (top.of the spring) until it flipped the rocker , it would work more like a toggle switch

Bill
wy omnibus Latinis taurus stercore?

Offline Brian Rupnow

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Re: Auto reverse mechanism
« Reply #55 on: August 23, 2017, 10:02:17 PM »
 I'm kind of hung up on this mechanism at the moment, and I've been busy with other stuff. I just spent today driving 390 kilometers  to see my mother and take her a birthday cake and celebrate her 97th birthday. I will probably get back to this sometime in the next week or two.---Brian