Worm gear for trailer ramps

[CustomRCmodels]

I have had motorized ramps on my Bruder as well Wedico trailers since years .
Mainly used for my tank-transporters for our tank-battle-events .
Therefore a screw-drive is out of the question , since the ramps need to be able to be pushed back down in case the tank ( or what ever load ) on the trailer twitches around and pushes against the ramps . You want them to be pushed back down without any damage to the ramp-mechanism .
On the Wedico drop-decks I use servos , with adjustable servo-delay so they come down and get up slow and so you can operate them via a switch , no prop channel needed , and since its a servo , they can get pushed back down without any damage .
On the Bruders I did first a setup with Tamiya's cheap toy-gearboxes with a crank to get the ramps up . But that was damaged to easy . Therefore I changed it over to winches .
The ramps are being pulled up via a tension spring and pulled down via the winch .
Here the same effect , someone can bump the ramps and they can be lowered without any damage .
The latest experiment ,which works fine , using a single Firgelli liner actuator , the 6Volt version , so it gets powered just over the servo-cable , but with the low gear-ratio of 50:1 , which allows also the ramps being pushed back down , since that low gear-ratio the Firgelli will move . Because of the 50:1 gear-ratio is would be fairly fast , therefore here also the use of a servo-delay module .