I was lifting a glass door freezer unit (like you'd see in the frozen food isle) with a Johnny bar. I has the bar on the rail of the case when it slipped off then the lip of the bar caught another part of the case launching it back up at my face hitting me in the jaw. I split my chin open (5 stitches) and bit thru my tongue in three places. It launched my hard hat 20' away, never knocked me out I saw a few stars but granted it hit me in the sweet spot I'm lucky it didn't KO me. Those damn bars are dangerous!!
I do all commercial work, did res hvac for two years my senior year of hs and a year after, F that noise!