In a countermarch loom, every shaft is actively involved in each shed: Each shaft is either lifted or pulled down by each treadle. Uneven sheds, for example a satin weave shed, where four shafts are lifted and one is pulled down, open cleanly every time. The warp ends on the fifth shaft do not tend to ride up as they often do with jack looms. When the shed is made, the same tension is applied to the raised ends as to the lowered ones, resulting in the best shed in relation to the increase of the warp tension. 

Look at the diagram to help you understand how a countermarch loom works. The points marked S are the pivoting points for the lams C and D and the jacks E. You will see that beneath each shaft, there are two lams associated with it. One of those lams is directly connected to the shaft and moves in the same direction as it does: when this lam is pulled down, the shaft moves down. When the other lam is pulled down, the shaft rises.

Contact Louet Support for  the complete document