Nope, it’s not the kind of shed you are thinking of. For a weaver, the shed is the space created when various yarns are lifted by the loom so the shuttle can carry the weft yarn from one side of the fabric to the other.
When you are dressing the loom, the shafts that control which yarns are lifted often get in the way of accurately threading the warp through the heddles. Since they are all on the same level, keeping the narrow metal heddles in the right order can be a challenge.
Some bright person (not me) came up with a slanted device that allows the shafts to rest on the wedge so each shaft is on a different level. This makes it so much easier to pick the correct heddle and avoid threading errors.
In the photo above, the wedge has lifted all 4 shafts in even increments, so you can select the correct heddle. When they are all on the same level, they seem to be in the same plane.
Here is the full-size prototype; it’s long enough that I can use it on either of my 4-shaft looms, or my 8-shaft. Yes, it appears woefully underpowered, except that it works as-is. My production models will probably be made of ply and double thickness. The joints are glued because I wasn’t sure how the tiny fingers at the tops & bottoms would work. (My way of playing with a concept to see what breaks. So far, nothing.) Dimensions are 1" tall x 4" wide at front, and 4" x 4" at the back; it’s 6" from front to back.
This was my first effort at creating finger joints. I didn’t want to use an online program because I needed to create the synapse connections in my brain for later work. Because I was using non-PG MDF, I didn’t want to have to hammer or force the fingers into place. As it turned out, everything was a close fit. With thicker material I’ll be able to use less glue, and design the fingers for a more decorative presentation. (thanks for the inspiration @evansd2)
It’s a heck of a lot cheaper than any I could have purchased from a commercial source! Weaving hardware is rather expensive.