The Black+Decker LM175 is an 18-inch 6.5-amp corded electric push lawn mower with a one-touch height adjustment, a polymer mowing deck, and a folding adjustable handle, designed for residential use. Model numbers include LM175 and 12411047.
The hard part is stopping the blade from spinning while trying to loosen the bolt that holds the blade on. Try wedging a piece of a 2 X 4 between the blade and the housing. When reinstalling, use the same trick. (works to remove props on outboard motors too).