"Roman blind" vertical opening gateway by Robin Hills

 Robin Hills Scout Group built this sliding portcullis gateway for KonTiki 2014. Robin Hills entered two teams, who placed 2nd and 3rd overall.

 The segmented door folds up out of the way when it's fully open, and slides down to cover the entrance when closed. The mechanism is similar to a Roman blind:

Two sets of ropes are tied to the door panels on each side. The dark blue set in this drawing are tied from the top of one panel to the next, fastening them to each other. The red set are tied to the bottom panel, and pass through holes at the top of all the other panels, before passing through a pulley at the top of the gateway.

 

 Pulling on the red ropes causes the bottom panel to move up, until it touches the next panel, when it stacks against it and starts pulling that one up as well. This continues until the entire door is smoothly stacked together at the top of the gateway.

Robin Hills built a sliding portcullis gateway for KonTiki 2011 that I blogged about here.