Are the patents for the Moog Ladder Filter still active?

Thread Starter

sciengart

Joined Mar 25, 2020
36
Does Moog still hold the patent for the Ladder Filter?

It is my understanding that patents become public domain after 20 years, and I cannot find a patent after 1968 for the ladder.
Does anyone know? Its a pretty useful and reliable filter, with just limitless possibilities!

I assume they do not, as many new synths now employ variations of the patented filter.
 

jpanhalt

Joined Jan 18, 2008
9,451
Several options:
1) Just do it. If it is still active, Moog will need to tell you. Usually, that is a cease and desist letter with no damages claimed.

2) Hire an attorney to do a complete patent search and give you written opinion. Probably at least $5.000 to $10,000 (my guess is closer to the high end), and if Moog decides to sue you anyway, it will be money wasted. If it wins, Moog will get damages regardless, and an affirmative defense (attorney opinion) is not much help in a civil court. If Moog loses, you still will be out at least $50,000 for attorney's fees.

3) Ask a bunch of anonymous people who don't have a clue (like me) and do whatever you want.
 

jpanhalt

Joined Jan 18, 2008
9,451
To all who have an opinion:

Netscape had an open and shut case against Microsoft. It sued Microsoft and won, but went bankrupt in the process. To anyone who thinks patent law is simple, you are the only simpleton in the equation. Why do you think even mediocre patent attorneys charge $1000 per hour at Jones Day?
 

wayneh

Joined Sep 9, 2010
16,390
I dont want to deal with legal bs.
Unfortunately there is no insurance against it. At best you skew the odds in your favor. No matter what, the only answer to a legal question like this is what happens in court. And that can go against all logic and legal opinions you might collect beforehand.

I suggest you do your own research to determine your comfort level with using “expired” prior art. One place I’d start is searching for later patents that cite the one you’ve found. That should uncover part of the landscape around that patent, such as later claims, patents in other countries and so on.
 

MisterBill2

Joined Jan 23, 2018
6,112
If you copy a patented design and do not sell copies for profit there should be no problem, since the purpose of a patent is to protect profits. So if you are not making a profit from it there is no issue. And depending on the claims portion of the patent, your copy may be different enough to not be infringing on the patent.
Trade Secrets are different, but once patented something is not a trade secret, by definition.
 

jpanhalt

Joined Jan 18, 2008
9,451
If you copy a patented design and do not sell copies for profit there should be no problem, since the purpose of a patent is to protect profits. So if you are not making a profit from it there is no issue. And depending on the claims portion of the patent, your copy may be different enough to not be infringing on the patent.
Trade Secrets are different, but once patented something is not a trade secret, by definition.
I disagree that personal, not for profit use is allowed for patents. First, check the law (https://www.law.cornell.edu/uscode/text/35/271 ) :
(a) Except as otherwise provided in this title, whoever without authority makes, uses, offers to sell, or sells any patented invention, within the United States or imports into the United States any patented invention during the term of the patent therefor, infringes the patent.
1) Fair Use does not apply to patents:
https://en.wikipedia.org/wiki/Fair_use
https://law.stackexchange.com/questions/18988/is-there-a-fair-use-for-patents-should-a-patent-be-licensed-at-a-reasonable-rat

2) Doing something in violation of a patent for "your own use" rather than profit is not a defense. The law is explicit that use alone constitutes infringement. As you imply, patent disclosure is done to get a grant of (limited) monopoly for a set period. Making something for "you own use" reduces the patent holder's profit should you have bought it instead.

While some have proposed a "fair use" doctrine applicable to patents in the US, the purpose is not to allow individual use without paying a royalty, but to spur creating of new products: https://scholarship.law.uci.edu/cgi/viewcontent.cgi?article=1002&context=ucilr So far, that has not become law.
 

danadak

Joined Mar 10, 2018
4,057
Can the filter be realized in another topology or architecture ? Can you do a network analyzer
sweep of filter to get its two port parameters and reproduce in another architecture ?


Regards, Dana.
 

wayneh

Joined Sep 9, 2010
16,390
I disagree that personal, not for profit use is allowed for patents. First, check the law (https://www.law.cornell.edu/uscode/text/35/271 ) :
Technically true but in practice it would be virtually impossible for the patent-holder to know if his claims were infringed. Lawsuits cost money and unless the TS is rich, famous, and performing with the device, it would be irrational for them to do anything more than ask the TS to stop.
 

jpanhalt

Joined Jan 18, 2008
9,451
Technically true but in practice it would be virtually impossible for the patent-holder to know if his claims were infringed. Lawsuits cost money and unless the TS is rich, famous, and performing with the device, it would be irrational for them to do anything more than ask the TS to stop.
I thought that was the first option I gave in post #2.

My later post was to point out that there is no "fair use" doctrine for patents yet in the US. It was not a suggestion of what to do, but rather to avoid spreading the common misconception that it was OK if not done for profit.
 

MisterBill2

Joined Jan 23, 2018
6,112
I disagree that personal, not for profit use is allowed for patents. First, check the law (https://www.law.cornell.edu/uscode/text/35/271 ) :


1) Fair Use does not apply to patents:
https://en.wikipedia.org/wiki/Fair_use
https://law.stackexchange.com/questions/18988/is-there-a-fair-use-for-patents-should-a-patent-be-licensed-at-a-reasonable-rat

2) Doing something in violation of a patent for "your own use" rather than profit is not a defense. The law is explicit that use alone constitutes infringement. As you imply, patent disclosure is done to get a grant of (limited) monopoly for a set period. Making something for "you own use" reduces the patent holder's profit should you have bought it instead.

While some have proposed a "fair use" doctrine applicable to patents in the US, the purpose is not to allow individual use without paying a royalty, but to spur creating of new products: https://scholarship.law.uci.edu/cgi/viewcontent.cgi?article=1002&context=ucilr So far, that has not become law.
If the infringement is not taking any profit away from the patent holder then it makes no sense for them to go after the infringer. If you look at the last 20 years of patent lawsuits it has always been because the infringement was taking away profits. And given the cost of lawyers it is not likely that any other reason would be cause for any action. At least that was the explanation I got with the patents that I was involved with. If the infringer is not making money or damaging my reputation then why bother??
Others are allowed to disagree with that, but really, why else go after somebody? Money or damage are the motivations.
 

joeyd999

Joined Jun 6, 2011
4,401
If the infringement is not taking any profit away from the patent holder then it makes no sense for them to go after the infringer.
Ah...so you wish to exercise the invention -- because it is of some value to you -- but you don't wish to compensate the inventor for that value.

Got it.
 

jpanhalt

Joined Jan 18, 2008
9,451
If the infringement is not taking any profit away from the patent holder then it makes no sense for them to go after the infringer.
Come on. You have not looked at the last 20 years of infringement cases. If so, please cite the 20 you feel have bearing on this matter.

You seem to be defending theft, so long as you don't get caught. Are you proud of that?
 

jpanhalt

Joined Jan 18, 2008
9,451
How do you define value in this context?

The invention may have no monetary value whatsoever to the "infringer".
THAT doesn't matter. Try that argument in court. "Yes, your honor, I stole his McLaren, but it crashed and burned, so it is not worth anything to me," won't fly outside California.

Maybe you two (you and MisterBill2) should move to California where Proposition 47 decriminalizes shoplifting up to $949.99 per event is allowed without prosecution.
 
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