Mechanics of a 3 speed shifting sequence

[sanddrag]

I have come up with a new idea for a three speed. Unfortunately, I can't say much about it at this time because I believe it has never been done before. Anyhow, one inherent problem in my design is that to shift from 1st to 2nd, it must momentarily move through 3rd.

Here is the shifts it can make without concern:

1st to 3rd
3rd to 1st
2nd to 3rd
3rd to 2nd

The shifts that cause concern are:

1st to 2nd
2nd to 1st

While making these "shifts of concern" the transmission would have to pass through third for an instant in time. Is this okay? It will never be in two different gears at the same time, but basically the shift sequence will be:

1st to 3rd to 2nd, or 2nd to 3rd to 1st, with 3rd being just a quick (fraction of a second) pass through. Is this a cause of concern or will it be okay? I tend to think it is not okay.

If it is not okay to shift this way, do you think the transmission will still be beneficial if it can not shift between 1st and 2nd?

If you are wondering why I would want a transmission with such an outlandish design flaw, well, it is incredibly easy to build.

[Kevin Sevcik]

The only problem I can see is if you're planning on using the tranny like a car tranny, shifting from 1->2->3 as you gain speed. In that case, going through 3r d to get to 2nd wouldn't work terribly well. For that matter, going from 3rd to 1st and 1st to 3rd wouldn't be a good idea either.

Since we're just using DC motors, though, this shouldn't be a problem. and using a tranny like a car's doesn't make too much sense anyways. So I don't think it'd be a problem in general practice.

[greencactus3]

i dont have a clue as to why your idea can only do those shifts. can you revise that to a 1-3,3-1, 1-2,2-1 only with no 2-3,3-2? or better yet 2-1,1-2,2-3,3-2, but no 1-3,3-1? then you can have it 'normally' in 2nd and shift down when you push and up for speed. so basically a 2speed+lowgear.
are you saying literally a fraction of a second? or figuratively? well in either case i think its a matter of driver.

[Stephen.Yanczura]

The only design I could think of that would restrict your 1-2 and 2-1 shifts would be some type of bassackwards three speed sequential transmission with the third gear (high) ratio in the middle position. [1-3-2] Versus a standard 3 speed sequential [1-2-3]. I would assume its a sequential transmssion because that's the only design I can think of that would yeild said shift restrictions.