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Old 08-18-2017, 08:32 PM   #31
Brian Rupnow
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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


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Old 08-19-2017, 03:46 PM   #32
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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.


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Old 08-20-2017, 06:55 PM   #33
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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.
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Old 08-20-2017, 11:17 PM   #34
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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.)
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Old 08-21-2017, 05:39 AM   #35
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Hi Brian.

I worked on chain driven self reversing mechanisms in my dim and distant past. The only problem they ever had was hang up at the point of changeover. There were usually two reasons for this. First caused by the driving gear disengaging before the toggle was fully over-centre. The second by the reverse gear engaging before the driving gear was fully disengaged. If this is not happening, then before you remove any material from below the rack, you may want to try lowering the strikers so that there is more movement of the toggle for less movement of the driving gear. It looks like you could clamp on some temporary strikers much lower down. The lower the better.
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Old 08-23-2017, 08:56 PM   #36
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Thank you for the suggestion Tony. 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
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Old 08-23-2017, 11:19 PM   #37
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Happy birthday to your Mum with many more
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Old 08-24-2017, 12:58 AM   #38
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Thank you Baz. She has been a great mother. My wife and I and my mothers younger sister (who is eighty eight) had a little birthday party at the retirement home where she now lives. I thought that putting 97 candles on the birthday cake might have set off all the sprinklers, so we only put 7 candles on the cake. For many, many years when I was a boy, my mother had a pen pal named Ruby Walmsly in Australia. They corresponded for many years, and my mother was always happy to receive mail from her "Friend in Australia". When I was about 10 years old Mrs. Walmsly sent my mother a small wooden boomerang souvenir of Australia about 10" long to hang on the wall. It was quite pretty, and had a kangaroo painted on it. After seeing it hanging there for about 6 months, and reading about the "bushmen" of Australia, I sneaked it off the wall when my mother wasn't looking, took it outside, and threw it as hard as I could. I fully expected it to return to me.---But sadly, although I looked for it for weeks, it was never seen again. I always thought afterwards that the damned thing must have flown back to Australia. I had a lot of difficulty explaining this to my mother-----Brian
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Old 08-24-2017, 01:12 AM   #39
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And another Happy Birthday to your Mum from me as well.

Quote:
Originally Posted by Brian Rupnow View Post
But sadly, although I looked for it for weeks, it was never seen again.
This made me smile. There is certainly a knack to throwing a boomerang, and if you did it correctly (which you may have accidentally done) and if it was a properly built boomerang (not just a pretty bent stick) then it would likely have traced a figure 8 path in the air, with the cross-over point of the 8 right where you threw it from. In reality, the throw has to be absolutely perfect for this to happen but it wouldn't have taken much for the boomerang to have landed behind you - possibly explaining why you never found it...


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