issue - Gearbox Drive Selector

[SNIPE]

Hi,

I am making a six speed gearbox but I am having significant trouble in enabling the gear lever to slide out of the drive selector clutch and into the clutch beside it.

This is fine if the drive selector is set to the middle setting as it lines up with the clutch for the gearbox but if it isnt then it wont be able to without moving back down to the middle position and changing clutches.

Any ideas?

[dhc6twinotter]

I'm not sure I follow, but if you're using a single drive selector (aka catch), each driving ring has to line up with each other for the selector to change from one drive ring to the other.

[SNIPE]

That's the problem, maybe I can have the driving ring push something into the clutch of the gear instead of the driving ring moving into the gear.

thing is , it wold have to be able to be pushed and pulled to disengaged and it has to stay where the driving ring put it even after the driving ring moves back from it.

its to select between front rear or 4 wheel drive

but I want it to have just one gear lever as its a car so

[dhc6twinotter]

I see. I'm not sure how you could do that with the driving rings right next to each other. However, if you space the driving rings 1 stud further apart than normal, you may have room to slide the selector out from one ring, then up/down and over into the other ring. The motion wouldn't be that fluid, but that's the only easy way I can think of to do it. The other option would be to use a selector for each driving ring and build separate shift linkage and shift lever.

If you plan on motorizing your vehicle, you may have a problem with the driving rings popping out under high torque applications. Hard to say for sure.

It sounds like an interesting project! I've never seen a vehicle that can switch between front or rear wheel drive. I do know a guy that has 4 shift levers for his transfer case....he has 3 transfer cases connected together (just the hi/low part), so he has a lever for each case. He has an additional lever that allows him to select between rear and 4wd. He can run his Toyota truck in triple low and in rwd if he wanted to. Plus, he has the manual transmission shifter too!

[Zerobricks]

Can you show soe pictures of the problem?

[legomuppet9]

I think what you are trying to do is have two driving rings engaged at the same time? I don't see why you would want this in a 6 speed gearbox, as you wouldn't want two gears engaged at the same time...

[LegoGBC]

Not sure if thats your problem (I didn't quite understand it) : Are you saying the switching lever is getting out of its 'slot' in the drive ring? If so,take a look at the 8043 gearbox - there is a simple technic to prevent this from happening.

It can be also seen in this image:

Edited June 29, 2013 by LegoGBC

[Alasdair Ryan]

Have you tried using a cam and a 'leaver' on a conventional set up to push/pull the selector in the further out one?

[SNIPE]

Here is a picture of the issue:

When it slides out of the red clutch its not going to go into the other grey ones but it needs to keep the position its in for which wheels are driven.

This is just the important parts here no gears underneath this or transfer cases etc.

I'm not sure I can picture the cam and lever idea can you make a model and take a picture/screenshot?

I don't understand what is going on in the 8043, this seems to have three gear lever forks?

Edited June 29, 2013 by SNIPE

[Zerobricks]

The lever has to be half a stud excentric in order to work properly...

[SNIPE]

oh, I forgot the angle the gear lever.

is this what you mean by excentric?

[DLuders]

In the dictionary, "Eccentric" means "not in the center" --

a. Not situated at or in the geometric center.

b. Having the axis located elsewhere than at the geometric center.

[Zerobricks]

The levers pivot point has to be in center of the 2L long axle connector. in your cause its not.

[SNIPE]

The levers pivot point has to be in the centre of the 2L axle connector. In your case it's not.

Ok, it is in the real model, it's just awkward trying to do it in LDD on a mac.

Here is my solution:

I made a custom clutch which pushes the two grey 'clutch extension rings' into the gears.

Note that the normal clutches will only slide a tiny bit (the axle joiners have 5 notches.)

The guide plate for the gear lever stops the regular clutch from going to the two endmost notches, this means that the custom clutch doesn't need to be as wide in order to enable the gear lever to slide to the regular clutches.

(Parts in pink represent the nuts and the threaded axle.)

The nuts will be inside of the grey clutch extension rings which stops them from rotating independently, everything but the gears and beams holding it in place will slide around.

I'll just use two half bushes in-between the two grey clutch extension rings, so the gear lever slot will be 1L.

Edited June 30, 2013 by SNIPE