In the last week or so I have been making this security post for my trailer. The trailer will be locked on to the ball hitch and the post will be locked upright, blocking the trailer in on my hard stand. The post will be welded into an anchor frame which will be set in the first layer of concrete, and the second layer of concrete will then fill up its sides to pavement level (over the cross bar which will anchor it further).
When folded down, the post will cross the pavement, allowing the trailer out over it and on to the road. I have yet to make the hitch lock, but otherwise it is all close to being done (and has only been delayed by my running out of Mig wire last night).