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Gear relation in clock won't work
iain_downs
Member Posts: 38 ✭✭
I'm modelling a simple clock here
https://cad.onshape.https//cad.onshape.com/documents/f99aa55da6675b042c4856be/w/23e1ba9aefb1ab2e6d82f886/e/72ff353f0125745c60e45552com/documents/f99aa55da6675b042c4856be/w/23e1ba9aefb1ab2e6d82f886/e/72ff353f0125745c60e45552 .
All the gears are in place and linked together with gear relations, for the main part they seem correct.
The one which is giving me trouble is the reverse minute to hour relationship. The ration should be 12 to 1. If I set it to that I get the hour wheel turning at about the same speed as the minute. If I set it to 1:1 the hour does not move. If I set it to 1:12, then the hour moves MUCH faster than then minute (12 times?).
I've tried breaking it down and building it back up, but the same thing happens. I have no idea what could cause this. Any help appreciated.
Iain
https://cad.onshape.https//cad.onshape.com/documents/f99aa55da6675b042c4856be/w/23e1ba9aefb1ab2e6d82f886/e/72ff353f0125745c60e45552com/documents/f99aa55da6675b042c4856be/w/23e1ba9aefb1ab2e6d82f886/e/72ff353f0125745c60e45552 .
All the gears are in place and linked together with gear relations, for the main part they seem correct.
The one which is giving me trouble is the reverse minute to hour relationship. The ration should be 12 to 1. If I set it to that I get the hour wheel turning at about the same speed as the minute. If I set it to 1:1 the hour does not move. If I set it to 1:12, then the hour moves MUCH faster than then minute (12 times?).
I've tried breaking it down and building it back up, but the same thing happens. I have no idea what could cause this. Any help appreciated.
Iain
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Comments
Iain
The model is really really awesome though. good work! way more in depth than my pseudo-clock.
I also echo Evan's comments about the number of mates for all the sub-assemblies.
I noticed that there are a few places where the gear teeth look like they are going to crash into other shafts, so you'll need to check your clearances carefully.
S1mon - The original design is metric and in Model Engineering magazine some years ago. I found it very difficult to follow the details in the article, so I wanted to redraw it in metric and use the process to understand how it was meant to work. There are some odd things (for example making the intermediate wheel a little smaller than it should be to avoid interfering with the winding arbor. I didn't like this, so may end up increasing the teath from 110 to 120 (or whatever) to give more space. VERY easy to do in OnShape. Hell with pencil and paper.
So there are still things to understand and sort out. I do note, by the way, that the pinions and wheels don't mess right and I should be able to fix this by rotating one or the other, but It's not high on my todo list.
Thanks again
Iain