16T clutch gears & lost motion

[doug72]

16T clutch gears lost motion. when used for co-axial drive through a turntable:

For my next MOC build I require a co-axial drive through a turntable for steering and drive to a 4 wheel under carriage.
The co-axial drive requires two red 16T clutch gears, a grey driving ring and  an extension driving ring.

Drive to steering via centre axle is OK and has no lost motion.

Drive to wheels via co-axial drive has 180 degs. of lost motion !!!

(Even more lost motion if use old red driving ring, grey clutch gears and two extension driving cones to get same length)

How to eliminate this lost motion with a solution that does not damage parts permanently ?

Solution:
BLUE TACK

The recess in the 16T clutch gears  & extension driving ring are filled with a small ammount of Blue Tack.

Take a small ball of Blue Tack and roll it out to form a rod approx, 1.5 mm dia.

Press this into the groove and then assembly all parts - squeeze all parts together.


Result:- NO LOST MOTION & no damage to Lego parts.

Edited February 11, 2018 by Doug72
Added text.

[Jurss]

Pictures?

[doug72]

28 minutes ago, Jurss said:

Pictures?

Please:

Edited February 11, 2018 by Doug72

[emielroumen]

Alternatively, an old style differential can be used too to eliminate some slack.

Edited February 11, 2018 by emielroumen
Typo

[doug72]

47 minutes ago, emielroumen said:

Alternatively, and old style differential can be used too to eliminate some slack.

Thanks - yes aware of that but the turntable is 1L too high so the 16T gear won't mesh with the gear drive to the wheels and keep 24T gear high enough to connect to motor output gears.
Seeing if I can lower the turntable so that it does.

A new (old) problem:
As turntable rotates the drive to the wheels also creeps - I recall this problem with the 8043 excavator when tracks moved as upper section rotated.

[Jurss]

I'm afraid that pure Lego solution other, than using old differential isn't possible.

Maybe somehow rerout side by side two axles, then center with u-joints, but it seems, that it will become pretty long solution.

Also, if you not use those clutch gears and things like that, they allow to turn turntable, without affecting that drive etc. If everything is fixed, of course, turning turntable will somehow turn also output. 

[Zerobricks]

Or use a differential instead of 16 tooth gears?

 

EDIT, oops, already mentioned.

Edited February 11, 2018 by Zerobricks

[doug72]

4 hours ago, emielroumen said:

Alternatively, an old style differential can be used too to eliminate some slack.

Have re-configured the turntable connection to under carriage and managed to lose the 1L height, allowing use of the old style differential housing OK.

[emielroumen]

Nice to hear! I thought about it during the build of Sheo's Terex. However, I couldn't make it work as it required quite a few changes and I just wanted to finish that beast.

[doug72]

18 hours ago, Jurss said:

Also, if you not use those clutch gears and things like that, they allow to turn turntable, without affecting that drive etc. If everything is fixed, of course, turning turntable will somehow turn also output. 

I had hoped to run both the steering and drive from motor & servo located in the rotating structure via a co-axial drive through the turntable but this appears to be impossible as when structure is slewed it affects both the steering and drive.
Is there a solution to this problem ?
I don’t think there is !

So back to the drawing board.

Edited February 12, 2018 by Doug72
spelling

[Johnny1360]

Ah-Ha, now I finally know what people are talking about when they say blue tack. I actually use that stuff quite often for non Lego things.

[emielroumen]

2 hours ago, Doug72 said:

I had hoped to run both the steering and drive from motor & servo located in the rotating structure via a co-axial drive through the turntable but this appears to be impossible as when structure is slewed it affects both the steering and drive.
Is there a solution to this problem ?

Not a true solution, but if you make sure you gear down after passing through the turntable, the effects are minimal.

[Jon61]

2 hours ago, Doug72 said:

I had hoped to run both the steering and drive from motor & servo located in the rotating structure via a co-axial drive through the turntable but this appears to be impossible as when structure is slewed it affects both the steering and drive.
Is there a solution to this problem ?
I don’t think there is !

I presume you're referring again to the issue you mentioned further above that arose eg with the 8043 excavator. I don't think this issue is completely avoidable, as rotating the superstructure inevitably applies an unwanted turning motion to the other shaft(s) (whether concentric or not) that go through the turntable. I believe the best you can do is to gear up (or at least don't gear down) the shafts before they go through the turntable, then gear them down afterwards. In this way, any spurious rotation introduced by rotating the superstructure has a lesser effect on the other functions (eg steering, drive).

Edit: Oops, posted the same answer almost simultaneously with emielroumen above.

Edited February 12, 2018 by Jon61
added postscript

[doug72]

35 minutes ago, emielroumen said:

Not a true solution, but if you make sure you gear down after passing through the turntable, the effects are minimal.

 

34 minutes ago, Jon61 said:

I presume you're referring again to the issue you mentioned further above that arose eg with the 8043 excavator. I don't think this issue is completely avoidable, as rotating the superstructure inevitably applies an unwanted turning motion to the other shaft(s) (whether concentric or not) that go through the turntable. I believe the best you can do is to gear up (or at least don't gear down) the shafts before they go through the turntable, then gear them down afterwards. In this way, any spurious rotation introduced by rotating the superstructure has a lesser effect on the other functions (eg steering, drive).

Edit: Oops, posted the same answer almost simultaneously with emielroumen above.

Thanks - No room to fit step up gears for both drive paths for steering & drive.
Therefore I have decided to go with either two PF cables through the turntable or alternatively only a cable for a PF Reciever which mounted on under carriage.
A stop to be used to prevent full 360 deg. rotation of upper structure.