View Full Version : When does Wisners 'patented' geared rear axis tilt expire???
With the expiration of Sinars patents on their camera movements allowing a lot of other makers to use the features I was wondering when the Wisner patents for his geared rear axis tilt expires? No one at Wisner wanted to answer this one so thought I would throw it out to the group.
Here's a link to what I believe is the patent you're referring to...
Wisner Patent (http://patft.uspto.gov/netacgi/nph-Parser?Sect2=PTO1&Sect2=HITOFF&p=1&u=%2Fnetahtml%2Fsearch-bool.html&r=1&f=G&l=50&d=PALL&RefSrch=yes&Query=PN%2F4814803)
It was granted March 21, 1989. I'm not sure what the life of these patents are however. Anyone else have any ideas?
Dug a little deeper at the US patent office site...
How long does patent protection last?
For applications filed on or after June 8, 1995, utility and plant patents are granted for a term which begins with the date of the grant and usually ends 20 years from the date you first applied for the patent subject to the payment of appropriate maintenance fees. Design patents last 14 years from the date you are granted the patent. Note: Patents in force on June 8 and patents issued thereafter on applications filed prior to June 8, 1995 automatically have a term that is the greater of the twenty year term discussed above or seventeen years from the patent grant.
What I interpret from that is, in the worst case, patent life is 20 yrs. This would put the patent expiry out to 2009...
You can start using this today if you make it for yourself! If you have a day job, it could be more profitable to let Wisner make the camera, and you make the money to buy it ;-)
Noone can stop you from ordering this stuff made to your camera at a local machine shop, except maybe your wallet.
Another camera maker can possible come around the patent by making it in another way - using screws on the back instead of the sides are probaly not enough.
I have never liked flatbed cameras until I saw Wisners patent drawings, making the lens rotate around it's center, instead of it's bottom, without adding the weight and bulk of a Sinar.
David A. Goldfarb
My 1890's American Optical 11x14" camera has geared rear swing along the lens axis, and I think I've seen this on some other cameras. The way it works is that the back of the camera is suspended in a frame with two pivots along the vertical axis, and there's a curved gear track several inches from the center (the radius of the curve is this distance) on the top surface of the back that meshes with a geared knob that goes through the outer frame. Turn the geared knob and the back swings along the vertical axis, and there's another knob to lock it in place with a simple clamping mechanism.
Is Wisner's geared rear axis tilt conceptually so different?
The 1995 change in patent validity was to prevent a practice known as submarine patents. This patent was applied for in 1987 (20 year limit) and issued in 1989 (17 year limit). It should expire in 2006.
For personal use, however, this isn't an issue.
Dan et al,
Feel free to copy our axis tilt mechanism for personal use. No need to worry about the legality, I herewith explicitly say "go ahead". The value it adds to many of our cameras (only about half of our product line has it) is obvious, but I am not sure it would compensate you for the time involved in making one in your home workshop unless you really enjoy such things.
Best regards, Ron Wisner
Ron, I do not know how I survived in the field without rear geared axis tilt before purchasing an 8x10 Expedition many moons ago. I would rather lose all movements up front than lose that. Thanks for building it.
Don't worry, I am not making a camera... with or without the feature. At least not for some time. It was just a question that popped into my head late at night & I thought it worth asking. I would have asked about Sinar or Linhof but couldn't think of anything they have with an active patent that can keep it off the open market.
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