Figures or drawings are not always required for a provisional patent. They are only required when they are necessary for one of ordinary skill in the field of your invention to understand your invention. Nevertheless, we strongly recommend submitting specific drawings that adequately depict your invention. This is because detailed illustrations make it easier for the USPTO to later associate a corresponding Non-Provisional Application with this earlier filed Provisional Application.
Furthermore, if you determine that drawings are necessary for one of ordinary skill in the field of your invention to practice your invention, the drawings you submit must be detailed enough to do so. If the drawings filed with your Provisional Application fail to meet this requirement, any corresponding Non-Provisional Application may not receive the Provisional Application’s priority filing date. Your Patent Attorney can help you obtain formalized drawings upon request.
If you are interested in more detail related to your situation it is best to speak with an attorney.
Yuri Eliezer heads the intellectual property practice group at Founders Legal. As an entrepreneur who saw the importance of early-stage patent protection, Yuri founded SmartUp®. Clients he has served include Microsoft, Cisco, Cox, AT&T, General Electric, the Georgia Institute of Technology, and Coca-Cola.
Source: Smartup Legal