USPTO Drawing Requirements
Drawing
The applicant for a patent will be required by law to furnish a drawing of the invention whenever the nature of the case requires a drawing to understand the invention. However, the Director may require a drawing where the nature of the subject matter admits of it; this drawing must be filed with the application. This includes practically all inventions except compositions of matter or processes, but a drawing may also be useful in the case of many processes.
The drawing must show every feature of the invention specified in the claims, and is required by the Office rules to be in a particular form. The Office specifies the size of the sheet on which the drawing is made, the type of paper, the margins, and other details relating to the making of the drawing. The reason for specifying the standards in detail is that the drawings are printed and published in a uniform style when the patent issues, and the drawings must also be such that they can be readily understood by persons using the patent descriptions.
The sheets of drawings should be numbered in consecutive Arabic numerals, starting with 1, within the sight (the usable surface). For regular nonprovisional utility applications, these “sheets” should be contained in an electronic document in PDF format filed with the other application documents via EFS-Web. These numbers, if present, must be placed in the middle of the top of the sheet, but not in the margin. The numbers can be placed on the right-hand side if the drawing extends too close to the middle of the top edge of the usable surface. The drawing sheet numbering must be clear and larger than the numbers used as reference characters to avoid confusion. The number of each sheet should be shown by two Arabic numerals placed on either side of an oblique line, with the first being the sheet number and the second being the total number of sheets of drawings, with no other marking.
Identifying indicia, if provided, should include the title of the invention, the inventor’s name, the application number (if known), and docket number (if any). This information should be placed on the top margin of each sheet of drawings. No names or other identification will be permitted within the “sight” of the drawing. The name and telephone number of a person to call if the USPTO is unable to match the drawings to the proper application may also be provided.
Source: USPTO.GOV