Dave,
I've made a simple drawing with de principle functionality of the scissor lift and its safety anchor. One of the sides, where the hydraulic cylinders are fed, the lower tube has a fixed position. That is the one to be anchored in the concrete. The other side is rolling during lifting and lowering. I just give the idea of one side of the tube. The other side is the same but mirrored.
Of course this is just the basic idea. The final design will depend on the lift you will buy. Some models have the lower tube closed at both ends. In that case you will have to grind the the end off to be able to slide the safety tube in.. The basic idea can be used on most models. A bit of improvisation is needed. Don't forget to use a lot of grease.
For bolting the anchor to the floor I welded two 12 mm threaded steel pins on a plate in the concrete at each side. Each bracket is kept in position with 2 nuts.
The advantage of this system is that the lift still can be removed quite easily - the four nuts are removed in minutes.
I hope this is more or less what you wanted to see.
