Just last Friday, during an arguement with my employer, the company president, threatened to knock me out. As it turned out, he didn't have to. I ended up being transported by ambulance to the hospital emergency room with severe chest pains. While yelling at the top of his lungs, he broke my keyboard tray by pounding it into my lap, during his tirade which went on for some minutes, and was witnessed by the whole front office. While I am 59 years old and considered myself in reasonably good health, I was shocked at the level of his response, and even more shocked to find myself in an ambulance on the way to the hospital.
The question is, did his actions constitute "assault"?
I have been employed at this firm for over ten years, and am considered by most, to be senior staff. While I value my position at this firm, I do not wish to leave there as the result of a heart attack brought on by my employer's frequent fits of temper.
I did not have a heart attack this time, the attending cardio-pulminary physician at the hospital said my chest pains were most likely caused by angina (caused by a lack of blood/oxygen to the heart muscle) however temporary it might have been. I will be scheduled this morning for a follow-up stress test, and other diagnostic tests.
I do not wish a repeat of my employer's threats or violent actions, but I would like to know the legal ground involved here. Thanks for any info you can provide.

If I understand correctly, your boss "struck" you with your keyboard tray. This would be considered assault. I'd suggest contacting local law enforcement and making a police report.

Regarding the behavior in the workplace:
Generally speaking rude behavior is not unlawful. I agree that it is unprofessional. However an angry tirade does not, in itself, break any labor laws. Since your disagreement was with the company president, I'm not sure where your next steps may lie. Normally I'd suggest to seek advice from HR or senior management.

cbg, can you offer an advice on this?

I'd still suggest discussing it with HR. I can't imagine that the rest of senior management will agree that this was a reasonable way of handling employee issues.

I understand about actual physical violence, but what about the verbal threats of physical violence. While that does not amount to "battery", does it amount to "assault" via the spoken threat, doesn't assault carry as part of its definition verbal threats of violence? I have not lived in Ohio my whole life, I have not had the need to examine law in ohio closely.

You don't need to worry about what part of it is and is not considered assault. Report the entire incident to the police; they'll figure out what is and is not criminal.