This thing was made with Tinkercad. Edit it online https://www.tinkercad.com/things/8cxFPa9Kwvl
I got tired of the wires going to my heated bed snagging on the frame, so I made this cable chain to contain the wires and route them properly. I'm not much of a designer, so I mostly used existing parts and tweaked them to work.
The cable chain segments/lids (resized to 75% of original size) came from
and the part that attaches to the bed came from:
The author of the strain relief gave me permission to post this, even though his work is licensed as No Derivatives.
I used these chain segments because they allow you to insert the wires without having one end free, something that was pretty important to me because I didn't want to unsolder the ends from the heated bed, and I didn't want to fish the wires out of the controller box. I ended up using 13 chain segments/lids on mine, it's possible yours may vary.
This mounts to the frame via the Y-Axis motor screws, which I had to replace with some M3 12mm screws (10mm would be better, 12mm is all I had, so I added some washers).
One note: I found that this chain interferes with the Cobra cooler when the bed is near the back. The blower fan will hit it.
I printed in ABS (technically only the part that touches the bed needed to be in abs, other plastics may melt). ABS also has a nice flex to it that lets you snap the chain segments together nicely.
Update: I'd print all of it in ABS, if you print a lot of ABS or have an enclosure. I have a few PLA parts inside my enclosure, and some of them have started sagging. Internal temperature of my enclosure hits 110F (38C I think) when I'm printing ABS. If you don't have an enclosure, probably not an issue.
I had to file the edges of the chain segments that touched the bed to get the chain to move smoothly.