What Is the Physics Behind the Sweet Spot on a Baseball Bat?

[berkeman]

I found a patent description
https://patents.justia.com/patent/20070151421

Looks like it's just a patent appliction. Do you know if it ever issued? Also, I was not able to find the diagrams/drawings -- do you see a link to them?

 

[Frabjous]

I do not have any experience searching patents. That being said, I found this
https://repositories.lib.utexas.edu/handle/2152/76860?show=full

edit: I changed the link
edit: Looking at the patent, I see that I remembered what he did at the beginning, not what he ended up with.

 

[sophiecentaur]

Looks like it's just a patent appliction. Do you know if it ever issued? Also, I was not able to find the diagrams/drawings -- do you see a link to them?

Thing about patents is that the only requirement to be granted one is that the description of the item has to be legally robust enough to challenge anyone who tried to copy it. There is never any guarantee that a patented device will actually work. The patent agents earn their money on all items and they just don't care about them, once the patent has been granted.

I think that quoting a patent is not a good argument about the Physics involved. That is, unless the device has sold well and has been seen to work for the customers. The Horse and Cart argument applies there.

 

[Frabjous]

I think that quoting a patent is not a good argument about the Physics involved. That is, unless the device has sold well and has been seen to work for the customers. The Horse and Cart argument applies there.

According to his webpage,
https://www.novacentrix.com/team/kurt_schroder
”He is also the inventor of the antivibration technology contained within most hammers sold in the United States, with sales exceeding $2B”

The story started with me saying that a friend from grad school after learning about centers of percussion in a classical mechanics class (in 1993) saw that hammers were not taking advantage of the physics and tried to do something about it. I thought it a nice story about physics being around us in everyday life. I then started getting questions.

After looking at the patent I remembered more. He started with adding/removing weight from the hammer and saw that it improved performance via testing. He then figured out that you could move the pivot point and improve performance and designed a handle to do that which he patented. While I cannot verify the word ”most,” I do know that multiple major tool manufacturers in the US brought out hammers with his idea.

 

[Frabjous]

Physics World did an interview with him
http://live.iop-pp01.agh.sleek.net/...edition/editions_nano_2018/article/page-26031

Here’s a quote

”I happened to walk into a Walmart and as I was looking at their hammers I realized every hammer that had ever been made had been designed incorrectly. If you hammer things all day long with an ordinary hammer, the shock and vibration will eventually give you lateral epicondylitis, or tennis elbow. Manufacturers knew this and designed the shape of their hammer heads to minimize this effect, but that leaves you with a hammer with reduced momentum transfer. I figured out that if you put air into the hammer’s grip in certain strategic locations, you can eliminate most of the shock and vibration, and that allows you to change the shape of the hammer to give it greater momentum transfer. Now, almost all hammers sold in the US have this technology in them. The invention has sold about $1.5bn in total,”