Need Inspiration? Consider These Patent Categories


By Mark Levy

Just when you think you can’t digest any more information about patent law, or patentability, or classifications of patents, or licensing, or claim interpretation - along comes another issue from the peculiar patent world.

Such is the case involving the three broadest categories within the gigantic utility patent umbrella - general & mechanical, chemical and electrical.Sometimes known as “types” of patents, these categories are so pervasive, the USPTO “Official Gazette” each Tuesday has for many years published information about every utility patent granted that week under one of those categories.

So with 3,500 patents issued and abstracted in the weekly OG, as it’s called, you’d think there would be all sorts of information about those categories, right? Nope. I found no documentation on the USPTO website or anywhere on the Internet describing or even defining these patent categories!

A call to the USPTO’s Inventors Assistance Center revealed little more. Though patient and knowledgeable-sounding, the gentleman I spoke with couldn’t point me to any patent category documentation, or say categorically (get it?) how they came into being.

However, according to the IAC representative, the categories are holdovers from USPTO tradition, from the days of old when people didn’t have access to cross-referencing. And that makes sense. Prior to USPTO computerization and online patent searching, anyone trying to find a single patent in the old hardcopy OG would be very thankful for any category system, no matter how generic.

While the usefulness of these ancient categories has dimmed, they still have value today. And that is in the form of springboards to more ideas. Simply by reviewing these dusty old categories, the inquiring inventor may uncover further problems needing their creative solutions in elegant ways he or she might not have otherwise considered.


Following is more detail on the three basic categories of utility patents used by the USPTO. 

General & Mechanical

When the U.S. Patent Office was created in 1790 and for an entire century after that, it’s safe to say that 99 percent of all patents were granted for mechanical inventions. You’d think that this being the 21st Century, and with people inventing mechanical solutions for thousands of years now, the mechanical category would be saturated. Not so. At least 50 percent of all patents issued are still mechanical in nature.

For the independent inventor, it’s even more - 90 percent of all patents applied for by solo inventors are mechanically based. That's not surprising when you figure most solo inventors not only think mechanically but actually can build a prototype to prove they can solve problems without an advanced degree.

So, mechanical-based patents are clearly still alive and well. As has been shown for two centuries in this country, even very simple mechanical ideas still get patented -- whether you’re inventing a better computer mouse or trap.


While burgeoning, the chemical category of inventing remains pretty specialized, requiring more investment and infrastructure than the typical independent inventor can muster. 

In addition to traditional chemical innovations ranging from fertilizer to medicinal drugs to gasoline, chemical inventions have expanded to include ultra high-tech biotech inventions, and genetic research. While not nearly as old as the mechanical discipline of inventing, sophisticated chemical inventions have been around a good number of decades.

In pharmaceuticals, for example, there have been as many advances since the year 1900 as was seen in all of recorded history until. That’s due in great part to the compositions that research corporations have found to cure diseases, prevent maladies and reduce pain. Today, there’s a pill out there for just about everything you’d go to a doctor for. 

With the advent of biotechnology, the chemical category is really exploding in terms of numbers of patents. Thanks to genetic research, we see things like vastly improved yields from fish farms and disease-resistant crops. I predict further, amazing advances in biotech, particularly in disease prevention, limiting disabilities and improving animal and plant systems.

Still, biotech is facing speed bumps. The introduction recently of the trademarked GloFish - a genetically engineered zebra fish that glows under black light - raised surprisingly quick backlash in the form of lawsuits by environmental groups fearing an accidental release of the normally docile household pet. As usual, the progress of technology should be balanced by caution and ethics.

Overall, chemistry holds a lot of untapped promise for inventors because it lends itself to compositions, methods of production, and methods of use. Not only do we have new patentable medicines that can improve whatever you can think of, but we’re seeing new methods of making the drugs using processes which are often patented if they’re not kept trade secrets.


Inventions in the electric category mean you're providing a solution or idea that requires a power source - whether that power comes from solar panels, batteries, or your wall outlet. Inventions could be anything from a new toy train, to an electric car, to the Mars Rover vehicles of 2004 which use both batteries and solar power. 

This category covers a lot of territory not dreamed of when the patent categories were established! Consider what the USPTO deems electrical - computer memory and chips, software (!), microwave devices, incandescent and LED lighting, motors, radar, PDAs, photovoltaics, DVD players, telephony, camcorders, television, home appliances, lightning rods, battery rechargers, and much, much more. A glance at a recent Official Gazette reveals a patent issued for a stamped-out piece of metal used simply to hold electrical wiring was categorized as an electrical invention, not mechanical. 

As with patents involving all other solutions, inventions in the electrical sphere aren’t patentable if they’re too theoretical or academic - such as trying to patent Ohm's Law or an electromagnetic law of nature. 

However, just about anything electric-dependent (or even electric-related) is fair game if it hasn't been done before and it’s not obvious. There are a good number of electrical ideas percolating through our social consciousness ever since dependable batteries (invented over 250 years ago!) and high-tension power distribution systems have been around. 


Whatever category of patent you choose to pursue, your invention must meet the basic requirements of patentability before a patent can issue. As we know, patentable inventions must be new, useful, and non-obvious. For more on patentability, see my earlier article, “What Kind Of Patent Should I Pursue?”

Still, that leaves a lot of wiggle room. To see what I mean, consider the following short list of my favorite ‘weird but true’ patents. For fun, look up some of the patent numbers below on the USPTO website and see if you agree with the categories I suggest they belong in. 

·  Automatic baby patting machine (US Pat. 3,552,388) - mechanical and electrical.

·  Chair made from garbage can (US Pat. 4,387,927) - mechanical.

·  Pet shower device (US Pat. 5,632,231) - mechanical.

·  Electrified table cloth that kills crawling bugs (US Pat. 5,107,620) - mechanical, electrical, chemical.

·  Communicating device using string and cans (US Pat. 4,195,707) - mechanical.

·  Human free-flight utilizing siege catapult (World Pat. 98/19760) - mechanical.

·  Nurturing of treelets utilizing human-cremated ash (US Pat. 5,799,488) - mechanical and chemical.

·  Combination bird trap / cat feeder (US Pat. 4,150,505) - mechanical.


Obviously, many patented inventions around us are nowhere near being simply a mechanical, chemical or electrical innovation. Many common, everyday products are easily a combination of two -- and some contain all three. 

Take the photocopier. Introduced in the 1930s to less than rave reviews, it has optics, toner, motors, servos, computer chip, software, metals, plastics, rubber, laser, fans, paper handling mechanisms, physical shape, timers, controllers, heat dissipation, power supply, and maybe even a patented external paint scheme. Each component may represent multiple patents, too. This product is just one example of how fields of invention can simply mushroom, and how innovations build on each other. 

So just because the USPTO categorizes an invention in one of three ways doesn’t mean it couldn’t, in the real world, just as easily qualify for another category. 

Are you in an inventing rut? Need inspiration? As a gentle suggestion, study a few issues of the USPTO Official Gazette. Look at the patents listed in categories in which you don’t have experience, then think about ways you could patent ideas in categories other than the one obvious to you. At the very least, broaden your current invention’s claims to cover more than one category. 

You may find yourself a whole new ocean of ideas to swim in. 

For more information

To view the three patent categories within the online Official Gazette, go to 
- Then click on any of the links under Published Issues 
- Then click Continue
- Then click Browse Patents Granted at the left
- Then click any of the categories under Utility Patents Granted at the left

For a free initial consultation, contact a patent attorney at Denver based Block45Legal today by calling us at (303) 353-4531 or submitting a form here.

Clement Hayes