Hi I am an Electronic engineer and we are going to build an Special Parking Gate; Our Parking gate opening direction we want to make should be something like the picture below; Do you have any Idea how is the best way to build this gate? My prime Idea is that Instead of a bar, we make something like a watch tie so by using a motor we can roll up the bar, but I have no idea how those Joint should be? In fact the joint should be locked when the gate is closing and be unlocked when the gate is opening! Do any body have any good Idea? ThanX in advance Shahriar.Farmanesh ?