Sunday, July 11, 2010

My Patent Application – Will It Pass the Novelty and Non-obviousness Tests?

The US patent office (USPTO) has four legal requirements that a new invention must meet in order to be patentable. It must fall into one of the USPTOs Statutory Classifications, it must be Novel, and it must be non-obvious to someone knowledgeable in the field of the invention, and it must be useful.

I’m currently getting ready to file a provisional patent application (PPA), and I’m in the process of writing the application. That will buy me some time as I will have one year from filing the PPA until I have to file a real patent application.

I’ve introduced my invention, a selective asparagus harvester, to the public by putting it up on a website, Having disclosed the invention to the public starts a one year clock ticking upon which a patent, real or provisional, must be filed to retain the patent rights.

I’ve chosen to stall having to spend $5,000 to $10,000 on a patent attorney as long as possible while I try to market the invention online. By filing the PPA I delay the date I have to file the real application by a year.

The first test, does it fall within one of the statutory classes, process, machine, manufacture, composition, or new use is easy enough. It’s a machine.

The second test, is it novel is one that I have to make sure is included in the text of my PPA. The PPA does not require claims like a real application. What it requires is that you provide a detailed clear comprehensive description of your invention. If any aspects of your invention are not included in the PPA they will not be covered.

I happen to already have a patent on an asparagus harvester issued on April 23, 1985, patent number 4,512,145. That machine never made it to market, but I’ve now made improvements on it and the improvements are what I hope to obtain a patent or patents on.

There does not seem to be any new patents that show anything to hinder my obtaining new patents on my machine.


Back to the novelty test… One of the changes I’ve made is in the cutters. Formerly the air cylinders required a second rod, a “guide rod” tied to and traveling with the piston rod to keep the piston rod from rotating. Rotating the piston rod will rotate the blade causing it to not be horizontal with the ground and possibly missing the spear you are trying to cut.

The problem was that the “guide rod” would not hold up for long before breaking. We tried all kinds of things, different sized rods, different methods of attaching the rod to the piston rod, welding, bolting, threaded connections, etc. They guide rods always broke and the nuts and bolts would always come lose… usually within minutes of beginning operation.

The novel method I discovered for keeping the blade in the proper horizontal plane is to use gravity. I dog-legged the blade mounts on the piston rod so that the blade and the heaviest part of the blade mount were off-set from the centerline of the piston rod. Thus gravity would pull the blade down to horizontal.

I consider this a novel new method and device for preventing blade rotation on an asparagus harvester. I can find no patents that teach anything about blade rotation and preventing it. I have found no patents that teaches off-setting the cutting blades. It looks promising to me.


The non-obviousness test would be my next challenge. According to my understanding the new invention must create some new an unexpected result. Let’s examine some background around the blade rotation issue.

If a guide rod or some other method of preventing piston rotation is not used with a standard pneumatic cylinder actuator they will rotate if an uneven force is placed on the blade that results in a torque (rotational force) on the piston rod. We ran into this problem on our earliest prototypes. Thereafter we used guide rods.

Persons familiar with pneumatic cylinder applications in industry are acquainted with guide rods as they are widespread in manufacturing operations throughout the world. Common alternatives include oval, square, and rectangular pistons and/or piston rods and piston rod bushings. Sometimes the guide rods are mounted internally to the cylinder and more often they are externally mounted.

Another method of preventing piston rod rotation is to use double side-by-side pistons and/or piston rod assemblies.

Another reason it isn’t obvious is that when the blades are in their retracted position the friction of the seals hold the blade in whatever position they were in when they reached the fully retracted position. You can fairly easily rotate the blades by pushing on them with your and or by using some other moderate force to apply torque to the piston rod.

When the piston rod assembly is in motion either extending or retracting the friction between the seals and the moving surfaces becomes near zero, allowing gravity to pull the dog-legged blades down into their lowest energy state, horizontal to the ground.

Thus, when the blade strikes the ground and the forces cause the piston rod to rotate, gravity will return the blade to horizontal as the blade retracts. If the blade does not make it back to horizontal by the time it is fully retracted then it will normally finish the job on the way back down, before it engages a spear.

There is one element of danger here. I haven’t done anything but an online computer search and thus might easily have missed an important piece of prior art that an actual professionally done search by a professional searcher at the patent office might uncover.

Hopefully that will be enough to show the patent examiner that my invention is indeed non-obvious.

Passing the final legal criteria, that the device be useful is obviously not a problem. It harvests asparagus much faster than a human can do it by hand.