4-speed compact linear gearbox

[Sariel]

So... I was working on something simple for my new Truck Trial vehicle, and I guess the 'simple' got kind of lost along the way:

The pros of this gearbox:

- 4 gears with large span of ratios

- full remote control with just 2 motors / pneumatic cylinder

- compact size

- rigidity and stiffness (the input & output axles are fixes, the shifter axles move by a single stud only)

- minimal amount of dead gears (zero at lowest gear, two at the rest)

Keep in mind that this design is not yet race-proven, but I hope you'll find it useful anyway. Also, if you want to operate it with a hamster, you will need a properly qualified one.

Description at my website coming soon.

Edited July 19, 2010 by Sariel

[Jurgen Krooshoop]

Looks promising. Something I will have to try.

[TechnicJuan]

How do you keep the gears from moving on the axle? Like when you pull the connector between the gear back, what prevents just the gear from sliding back on the axle?

I know those bevel gears don't normally fit very tight onto axles.

[Sariel]

How do you keep the gears from moving on the axle? Like when you pull the connector between the gear back, what prevents just the gear from sliding back on the axle?

If you shift gears fast enough, there is no problem. The gears fit each other well and there is almost no grinding while shifting gears, which is thanks to the use of double bevel gears only, and to the reduced differences in gears' diameters.

Edited July 19, 2010 by Sariel

[DLuders]

Slfroden posted this

of a "slightly modified version of Sariel's 4-speed Compact Linear Gearbox ( http://sariel.pl/2010/07/4-speed-compact-linear-gearbox/ )." The video shows "A proof-of-concept to realise the control of two gearbox selectors using a single Lego linear actuator and a single Lego motor.

When the the linear actuator extends it moves two linkages. The bottom linkage has a stretched white rubber belt, and as the belt begins to contract and this causes the bottom linkage to move first. Once the bottom linkage can move no further, then the top linkage begins to move.

When the the linear actuator retracts, the top linkage moves first, followed by the bottom linkage....Unfortunately this set-up only uses three out of the four available gears in the gearbox."

[jorgeopesi]

Simple and perfect use of rubber band.

[Splat]

Slfroden posted this

...

Hi DLuders, thanks for posting my video. 'slfroden' is my other nickname on the internet when 'Splat' is already taken.

I'm still trying to work out the best way to put together a 4 speed gearbox with 2 outputs (as detailed in this post). Any help would be appreciated...

[LEGO Train 12 Volts]

This is simply impressive!

Technic forum leave me always speechless!