Auto-Rewinding Cord Reel

This reel was designed to manage the power cord on a fuel pump that I use at work. Wrapping the cord around a spool was a pain, not to mention the constantly tangled wires. I based this idea off of the little auto-rewinders that they use on headphones and earbuds, only I scaled it up to a more industrial size.

This utilizes the recoil spring out of a Troybilt TB22 trimmer I had laying around the shop. According to diagrams, this particular spring is available only as a part of the recoil housing assembly, but it's a pretty standard design among 2-stroke trimmers, so it should be relatively easy to track one down.

Once the wire is wound on the reel, you simply pull on both ends at the same time to retract the cable as far as you need and press the handle down into one of four holes in the reel to lock the reel in place while the cord is in use. Once you are through, just lift the handle and the reel will retract the wire back into the spool, ready for the next use.

Assembly

Once all the pieces are printed, start by running the wire through the hole in the center disc of the inner_reel so that equal lengths are protruding on either side. Thread the wires through the holes in the upper_half so that the wire on the upper portion of the inner_reel comes out of the upper hole and the wire on the lower portion of the inner_reel comes out of the lower hole. Slide the inner_reel down onto the center pole.

Next, wind the reel in the direction of the arrow. This will wind the wire up on the reel and prepare it for retraction. You may want to tie a knot in each end of the wire so that it can't be accidentally pulled through. Trust me... I did this several times while working with this design!

I found it easier to place the spring assembly down on to the inner_reel first, but you can place it into the lower_half if that's easier for you. Either way, once the spring is in place, combine the lower_half with the upper_half. Don't engage the alignment pins with their corresponding holes just yet.

Turn the lower_half clockwise (when looking at the unit from the bottom) to pretension the spring. Twist until you feel tension and then let off 1/4 to 1/2 a turn until you can align the pins in their holes. Press the two halves together and secure the shell together with a 6mm bolt and nut.

Attach the handle to the upper_half with a 3mm bolt and nut.

Your AutoRewind Reel is now ready for use!

I recommend at least 1.6mm walls (4 walls thick with a 4mm nozzle) for strength on all components.