Worm gear for trailer ramps

[Supermario]

This video is exactly what I want to do on my RC4WD lowboy trailer ramps. Both ramps are on one common shaft like this bruder model. My question is where do I find a worm gear set like this and a motor to run?
Thanks for any info or suggestions

http://youtu.be/ZCLcxScctV0

Mario

[WhiteWolf McBride]

It'd work on the Carson Goldhofer STN-3L as well...

I see in the desc he's using a 1:10 winch, probably the stock RC4WD one, but how to connect that to the screw-drive-shaft, and then where to find the steel worm-gearing for the shaft-to-axle-hingepin...

Bet a lot of others would likee the 'hint' too... all the vids I've seen show the ramps being operated from topside... or a still of the underside w/o close-up or showing it in operation.

Anyone?

WhiteWolf

[kaptain Jack]

Steel worm gearing is commonly used in rc helicopters and parts are available in all the heli stores.

[WhiteWolf McBride]

Hmmm, will have to drag my trailer into the local hobby shop to see about getting some 'parts'... why?

For simple 'test', even if one shatters the gears first time out, there are a few Tamiya worm-gear kits. (fishes for pics/links) Hmmm, seem to be more than a few of them. Here's the run-down:

The 72004 High Efficiency Kit allows 216:1 & 336:1 ratios, uses included RE-260 motor, can take an RE-130/140, $12.39 @ Tower.
( http://www2.gpmd.com/imagel/t/ltamx7204.jpg )

The 72008 4-Speed Kit, with ratios of 1428.2, 555.4, 216 & 84:1, again using RE-260 motor & accepting RE-130/140 motors: $14.69 @ Tower.
( http://www2.gpmd.com/imagel/t/ltamx7208.jpg )

The Planetary Set is also RE-260 powered, can take RE-140, the only in-line unit, and has ratios of 4, 5, 16, 20, 25, 80, 100, & 400:1. At 400:1, its about 15 kilos or torque. $17.99 at Tower.
( http://www2.gpmd.com/imagel/t/ltamx7201.jpg )

Thing is, none are really compact, but Tamiya does make some Mini-Motor sets, $11.99 each at Tower. The 12-speed unit goes down to 209.8:1 (30 rpm) & 946 gf-cm, the 8-speed goes down to 87.8:1, but the 4-speed goes down further; 71.4, 149.9, 314.9, & 661.2:1. All seem to have a 20mm box-height, and use a 030-size 3v motor.
12-speed: ( http://www2.gpmd.com/imagel/t/ltamx0190.jpg ); 8-speed ( http://www2.gpmd.com/imagel/t/ltamx0188.jpg ) & 4-speed ( http://www2.gpmd.com/imagel/t/ltamx0189.jpg )

Then I went looking for just worm gears. Only one found, a stainless one from RobotShop for $45 and change. OW. Gonna have to consider harvesting a heli shaft-drive tail-rotor gearbox, or cannibalizing a 90-degree drive offa sommat...

Then I considered the problem. The shaft has to be stationary at the ramp-end, using a gear to make the ramp-hinge-axle rotate. This requires some re-thinking and perhaps cheap f abrication to 'solve' the problem.

WhiteWolf
Sorry, image-linking dinna work)

[WhiteWolf McBride]

Guys...

Found a Youtube vid of a German modeller who rigged his Goldie, and he posted a thread to a German forum on how he rigged his trailer! Whee!

Anyone able to translate the German, or should I just use one of the online ones? I'll do it and post if people want me to...

Link to his actuator solution here.

Link to the video where he posted the how-to link.

Now, who would be interested in asking one of the machinists to make us some metal ramp-mounts? I think the more sets we buy, the cheaper it'll be per set, right? I'll front for 'em if it helps... And once he has the masters, he can make more for 'other ramps'... right?

WhiteWolf

[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 .

[WhiteWolf McBride]

Willy, Willy...


Pictures, where to get the parts, and how much they'll cost.

Please?

WhiteWolf

(hokay, I googled 'em - seems Firgelli is a Canuck company, out in BC! Now its what size/type to use... OW, they ain't cheap, are they! Think a servo/winch is a better idea...

[CustomRCmodels]

Originally Posted by WhiteWolf McBride

Willy, Willy...


Pictures, where to get the parts, and how much they'll cost.

Please?

WhiteWolf

(hokay, I googled 'em - seems Firgelli is a Canuck company, out in BC! Now its what size/type to use... OW, they ain't cheap, are they! Think a servo/winch is a better idea...

I gone post some details as soon I catch a brake .
At the moment I am working on getting ready for our next Danville tank-battle-event in June ,
and I am also working on some new gearboxes for our tanks.
( some real cool stuff ! )
In the meantime , there are several videos of my tank-transporters on my own Youtube channel as well from the HEAT armor club and others ...
search for Danville R/C tank battle events .....

[WhiteWolf McBride]

Hokay Willy,

I'm not in that much of a rush. I keep telling friends about the vids, I should download and store 'em on my laptop.

Any thoughts on who might be willing to replicate the Goldie's ramp-hinge mounts? Once mastered, they could be used for almost any trailer... or has someone already begun this task?

WhiteWolf
- gotta ask my garage about powdercoating my Goldie...

[Supermario]

I understand what your saying about a worm gear allows no give Willy. I was planning on drilling larger diameter holes in the shaft than the bolts or pins that hold the ramp to the shaft. Or slotted holes on the ramps and the pin locked to the shaft.
The nice thing about the RC4WD ramps is they go over center when up so once the flop the ramps have a little give in both directions.

I think something along those lines would work.

I've been doing a little basic searching on worm gear sets

https://sdp-si.com/eStore/Catalog/Group/175

But I guess I need to know motor shaft size

I have enough on the go right now, this a must do item for the lowboy but probably won't happen in time for Indy this year. Next year for sure

Mario