Flat bar grate can sometimes get bent out of shape, and doesn't lay flat. It only needs to be out of place by a small amount to cause a tripping hazard. This bar is made for prying the grate down to a flat surface to allow it to be welded in place. If you are not familiar with this type of grate, the second drawing shows it in detail. The "finished view" on the first drawing shows the end view of the grate.     

     It works by first welding the grate in place in any spot where it does lay flat. From there it is only a matter of hooking the bar under the 1/4" round, using the welded area as an anchor. Slide the angle iron clip along the pry bar to a suitable place to give it leverage, and push down. The grate under the clip will be forced into place and can then be welded, allowing the process to be repeated again.

     The advantage to this bar compared to clamps is that it can be used anywhere on the entire section of grate, whereas clamps are limited to use on the ends of the grates only.