Some time ago I initiated an inquiry about powered trailer jacks. I wanted to share the solution I implemented.
When I back my gooseneck flatbed trailer into the shed, the crank is right next to the wall making it dificult to crank the jacks. Powered jacks would be great, but wow the cost of commercial units. Looking for a cost effective retrofit I came up with this. Here is a link to the Yahoo photo album where the pics reside;
The machined adapter has a key and sprocket to provide a drive to the jack drive shaft.
The gearmotor is a Harbor Freight ATV winch. It comes with the reversing switch and wires and the ability to disengage the motor to freewheel the drum. Necessary if the battery is down or the motor fails. I disassembled, removed he cable and the drum. I machined off one flange and milled in a keyway. Now I could attach a sprocket to the hub of the drum.
Fabricating a simple plate and bracket allowed attachment to the trailer gooseneck upright. Some #40 sprockets and chain from the local farm supply store (Rural King) and I was done.
It works well but is slow. I looked at changing ratios with different sprockets, but there are limitations. The driver (winch gearmotor) has the bracket so you cannot go too large. The shaft adapter (driven) can only accept so small of a sprocket because of the hub size. So I am pretty much stuck with what I have. I do not recall the number of teeth, but I'll get them if someone wants to know. Ratio is slightly overdriven but close to 1:1.
By slow I mean that it probably takes a minute or so to raise or lower the jacks when hooking or unhooking the trailer. Not a problem and something that can be lived with.
Total investment was about $50 for the winch and about $40 in chain, sprocket and misc. The materials (a 1/2" plate and a shout piece of
3X5 tubing) came from the stock pile.I hope that this helps someone else
Bob