A skeleton tie-up is a bare bones tie-up which allows the greatest number of sheds with the least number of treadles. For summer & winter, that means that the tie-down shafts are each tied to their own treadle, and the pattern shafts are tied to different treadles. This requires two or more treadles being pressed at the same time in order to create the correct sheds. I've just learned how to figure these out, so hopefully I can explain it to you.
I'm going to start my study of tied unit weaves with a 3-block summer & winter, so that's what I'll use as an example. The first thing I did was to figure out a complete tie-up, which shows all possible sheds for three S&W blocks. It looks like this....
.... and requires 18 treadles.
In the complete tie-up, the pattern shafts (3 through 5) are always paired with first one tie-down shaft and then the other. For example, 1 - 3 then 2 - 3. However, if shaft 3 is tied-up by itself and treadled together with one of the tie-down shafts (1 or 2), then the same sheds can be made, but with one treadle tie-up eliminated. To do the same for each combination of shafts, the skeleton tie-up looks like this:
This skeleton tie-up for jack looms requires only ten treadles. All the shed combinations are possible by using two treadles at a time, except the tabby sheds, which are tied to the two treadles on the right ( 9 and 10.)
More blocks would require more treadles, so you can see why folks would be tempted to get a dobby loom!
Posted 15 Oct. 2008 at http://leighsfiberjournal.blogspot.com
Skeleton Tie-Ups for Countermarche Looms
Summer & Winter: Tie-Up