Monday, April 14, 2014

Multidirectional Winch Mount on Spare Drawbar

We have a small trailer and an even smaller driveway -- in order to get the trailer onto the driveway and off the sidewalk, we have to pull it at a 45 degree angle from the street, all the way up to a wall next to our garage.  There is no room to pull it with the truck -- it has to be winched up.

That is the problem:  because the winch was pulling the trailer up at a 45 degree angle, the cable would inevitably pile up on one side of the winch drum.  One day, the cable hopped out of the drum and got tangled around the axle of the winch drum.  Bad situation.  I eventually rescued the winch by laboriously untangling the cable, but that arrangement was clearly inadequate.

So, after much consultation with my helpful buddies on rv.net, Felice and I developed the following arrangement:  the winch is mounted on the back of the truck, attached to the hitch receiver.  (More on that later.)  The truck is pulled into the garage so that the winch sticks out of the garage a foot or so.  The cable then runs across the front of the garage to a pulley.  The pulley is anchored to the spot on the driveway where we want the trailer to go.  (More on the anchor later.)  The cable then runs down the driveway to the chains bolted to the tongue of the trailer.  We put it all together, and it works!

Here is a crude diagram of the setup:


Pulley -------------------- Winch
\
  \
    \
      \
        \
    Trailer

Here is how the winch is mounted to the back of the truck:  I had a spare 2" drawbar/ball mount sitting around -- it was from our old trailer, which had a smaller rise.  This drawbar also had a sway bar mount welded off to one side of the bar -- which came in very handy for mounting the base plate of my winch mount.  Using my drill press, I drilled a couple of extra holes through the drawbar and then ran several heavy half inch bolts up through the holes and through a thick piece of plywood -- this is a picture of the underside of the base platform:


Here is a view of the top side of the base platform -- notice the 3/8 bolts sticking up through the base platform, which will go up through a separate piece of heavy plywood, to which the winch is attached:


(That horseshoe-shaped thing in the upper right is a very powerful magnet, scrounged from a dead computer hard drive -- I use it to hold the wing nuts during assembly, as shown later.)

And here is the winch on its base, which is mounted onto the projecting studs -- my finger is pointing to one of the studs:



Finally, thick washers and wing nuts go onto the studs to hold the winch in place on the platform:


By placing the studs at exactly symmetrical intervals, I can now dismount the winch base and rotate the winch by 90 degrees or 180 degrees.  So if I ever need to use it out in the boonies to pull the trailer out of trouble, and I can’t align the truck so that the winch is pointing in the right direction, I can just realign the winch.

This shows the alignment of the winch on the back of the truck, the pulley (in front of the trailer), and the trailer:


And this is the pulley, mounted on a bolt sunk into the driveway:


The bolt is not permanently attached to the driveway -- I drilled a deep hole in the concrete with a carbide bit.  The bolt then drops down into the hole.  A big washer covers the hook at the top of the pulley.  We watched to make sure that the bolt did not move when we were pulling the trailer up the driveway -- it did not budge.  The tension on the cable created a tight fit in the hole.  But then when we were done moving the trailer, it was easy to lift the bolt out of the hole -- no hardware left in the driveway to trip on.

I am planning to get a “snatch block” to replace the pulley -- a snatch block is a pulley in which the two halves or “cheeks” rotate apart, so that the cable can be easily placed into the pulley and later removed.  With our current setup, the pulley is on the cable permanently.

Finally, notice (in that prior picture) that I have three clips or clamps on the end of the wire cable.  The minimum is two, but I wanted an extra margin of safety.  After a little Internet browsing, I discovered that the arched end of the cable clamp should be over the “bitter end” of the wire, rather than over the working portion of the wire.  I don’t know why that is the rule, but it is, and I figured I would just follow the herd.