Garage floor drain cover

After years and years of salt and road water dripping and running in to my floor drain, the cover has pretty much disintegrated. Now I have a deadly 8 inch hole. Did some searching online for covers and found some cast iron ones. But not sure what actually held the old one up. Theres not really a lip or anything to set it in. Atleast not that I can see. Any suggestions would be greatly appreciated.

No way to answer your question without seeing the drain or a picture of it. Most cast iron covers set into a recess, but since they are fairly thick the recess has to be sized for them.

Thanks HJ

Making a half hearted attempt to upload a photo of the drain but have my doubts whether it will help. Thanks again.