very similar invention to one with expired patent - Can I file with my specs?

[amport]

What is the name of your state (only U.S. law)? California.

I have a invention for which I have created a working prototype with full design specs. I had planned to explore applying for a patent so I performed a cursory patent search online (at the USPTO database) where I discovered a nearly identical invention that was patented in 1991.

My assessment is that my invention is very similar in design, shape and function with only some minor differences in design.

My question is the following:

Since the original patent has expired, I assume that I cannot reapply under/with my invention due to the distinct similarities in both design and function. Correct?

If this is correct, is it safe to assume that Product (With this unique design and function) is now under Public domain?

Or, can I reapply with my invention and be considered for a patent even though there are significant similarities with the 1991 invention.

Any info/direction you can provide would be appreciated.

 

[quincy]

What is the name of your state (only U.S. law)? California.

I have a invention for which I have created a working prototype with full design specs. I had planned to explore applying for a patent so I performed a cursory patent search online (at the USPTO database) where I discovered a nearly identical invention that was patented in 1991.

My assessment is that my invention is very similar in design, shape and function with only some minor differences in design.

My question is the following:

Since the original patent has expired, I assume that I cannot reapply under/with my invention due to the distinct similarities in both design and function. Correct?

If this is correct, is it safe to assume that Product (With this unique design and function) is now under Public domain?

Or, can I reapply with my invention and be considered for a patent even though there are significant similarities with the 1991 invention.

Any info/direction you can provide would be appreciated.

In order to qualify for a utility patent, your invention must be novel and nonobvious. Your invention does not appear to be either. You can have a personal review of the particulars by a patent attorney in your area to determine this better.

Here is a link to the USPTO for information on patent law: http://www.uspto.gov

 

[FlyingRon]

Whether the other patent has expired or not has NO BEARING on whether you can file.

Yes, once a patent is expired, it's in the public domain. However, once an invention is patented it IS DISCLOSED. It ceases to be novel. If your invention had some novel and non-obvious claim that extends the existing invention, you could obtain a patent even if the original patent was still in force. You'd obviously need permission from the patent holder to use his invention in addition to yours in while his patent is still in force.

"Minor design changes", as Quincy points out, don't sound like they meet the non-obvious requirement for something to be patentable.