To properly write a provisional patent application, it should have 1) a complete description of how the invention works and 2) a set of technical drawings that help explain how the invention works. The key concept is that a provisional patent application must fully describe how the invention works, including the components that make up the invention and how the components are arranged. If any portion of the invention is not clearly described, it is not protected!
You protect only what you describe, so write as much as possible.
It is a common misconception that a provisional patent application does not need to be written in detail. After all, it’s just a provisional or temporary patent application right? Wrong! What is not explained is not protected. Think about it, if I filed a patent application with one sentence and it said, “A machine that can travel through time”, do you think I can stop anyone from ever making a time machine or prevent anyone from saying they invented a time machine before I did? Of course not. Unless I actually know how to make a time machine, including all the components that it needs, and how to put it together, I cannot get even provisional patent protection. So the first thing to remember is you must explain how the invention works in full detail.
Do you have the technical background to describe how the invention works?
Describing the components of the invention and how it is arranged is not something every inventor can do properly. For example, if your invention has an actuator, do you know what other components it is attached to, and how it contributes to the overall working of your entire invention? Can you further explain it? A provisional patent application should be written in such detail that someone reading the application can recreate the invention. If you don’t have an engineering background, you will want to have a patent attorney or agent prepare the patent application. Often, even patent attorneys and agents further take on the help of engineers who specialize in the field of your invention to assist in preparing the patent writing. This is because the quality of the patent application heavily relies on how well the invention is described form a technical viewpoint. Even if you have an engineering background, it is best to have someone else as a professional write the patent application. Remember, the patent application should disclose the invention in sufficient detail for someone else to make the invention. You know your invention already and your patent application writing may skip over details you think are not important, although someone else reading the application may not understand. It is therefore best to have someone else write the application to make sure others can understand how your invention works, not just you.
Detail how the invention works, not what the invention does
A patent application needs to focus on how the invention works, not what it does. These two are very different. If I say I invented a machine that can travel through time, I’m talking about what it does. However, a patent application requires disclosure on how it works. Namely, what components make up the invention, how those components are assembled, and how those components allow the invention to work. Many inventors get carried away in describing what their invention does, how great it is, and how it will change the world. However, the Patent Office cares more about how the invention works, and less about what the invention does. If you don’t include enough detail about how the invention works, your invention is not properly protected in the patent application.
Prepare technical patent drawings
Visuals are important in helping a reader understand how an invention works, and we discussed already that the protection of a provisional patent application is based on how well the patent application allows someone to understand how the invention works. Therefore, drawings are an important part of the provisional patent application. For technical individuals to understand how an invention works, they rely on technical drawings. Patent drawings are often technical drawings done in computer aided design (CAD) which show all the components of an invention and how the components are arranged. Patent drawings sometimes show the invention cut open, or exploded, to further show how the components are assembled. Unless you can prepare technical patent drawings, it is recommended to have a patent professional prepare these to ensure your invention is properly protected in the patent application.
Summary
A provisional patent application protects only the detail you clearly explain regarding how your invention works. The less detail you write, the less it protects. The less technical writing or technical drawing you include, the less it protects. Remember the above “time machine” example. If I file a provisional patent application with just a few sentences saying I invented a time machine, I will have no protection. Have a patent professional understand your invention and prepare a full set of patent writing and patent drawings to fully explain how your invention works.