LEGO gearbox question

[aminnich]

Hey guys, I notice that gearboxes are being built all the time. My question is, Are these gearboxes made to shift while moving? so that the momentum of the vehicle keep going. Im not really sure how to word this, but I hope it can be answered.

[TheNextLegoDesinger]

all the ones that i used i had to loose the throtthle shift and throttle up again so the gears wouldn't get stuck. if it is for a car you can use a one-way clutch.

BTW i only used Sariel's heavy duty gearbox and his speed gearbox he made in the beginning of this year

[aminnich]

Has anyone used a clutch in their model before?? I feel like the idea of a gearbox is almost pointless without a clutch.. This is totally different for functional gearboxes, I am only talking about speed gearboxes.

[TheNextLegoDesinger]

yeah i know. what are you using it for?

this is the heav y duty 2 speed gearbox i used

2-speed-gearbox 2 by thenextlegodesinger, on Flickr

[bonox]

Has anyone used a clutch in their model before?? I feel like the idea of a gearbox is almost pointless without a clutch.

depends on function versus accuracy in modelling a real unit.

Since the electric motors can be speed controlled down to zero rpm and produce significant torque at low speed, you don't need a clutch to get an electric vehicle started. You can also shift a manual gearbox without the clutch if your control of the motor/engine is good enough or you use something like a zeroshift design which can change ratios under torque loading (http://www.zeroshift.com/).