This is model 13 in the 1928 set 6 manual. A YouTuber called newspaniard has been making all these models but did not succeed with this one because he couldn’t work out how to build it. I found it very difficult from the instructions. The back of the model is not shown. Also references are made to a ‘belt striker’. Maybe in 1928 these were commonplace but now it is necessary to guess a bit.
Linen is wound from the lower roll onto the top forks. Once enough has been wound, the drive is disengaged by moving the belt striker to the right, so the belt (no shown) goes to a free wheel pulley. Then the left hand mechanism near the forks is moved away to allow the linen to be removed. The vertical rod is meant to be a rev counter.
In my not so humble opinion this is an ill-conceived model and good for newspaniard for not building it.