Kevin Mark Klughart
PhD, PE, JD, MIP, LLM
Patent Attorney / Engineer
USPTO Drafting Standards
The subject of Patent Drawings often comes up in the discussion of the preparation of a patent application. Patent Applicants should be aware that the USPTO has strict requirements for the form and content of patent drawings and will reject applications which do not conform to their specifications. Unfortunately, industry standard formats in the mechanical and other arts are not necessarily acceptable to the USPTO. While many inventors with moderate CAD skills can utilize common tools such as AutoCADŽ and other similar products to generate acceptable drawings, conformance to USPTO drawing specifications must still be followed. A copy of the USPTO Guide for the Preparation of Patent Drawings [7.5 MB] may be useful in preparing properly formatted drawings for your patent application.
Inventors may also find useful the textbook "The Patent Drawing Book" by Jack Lo and David Pressman (NOLO Press, ISBN 0-87337-378-2, 1997). While I don't necessarily agree with all of the content of this text, it does provide some additional insight into proper patent drafting practices.
While there are a plethora of CAD drafting tools on the market, most inventors are surprised to find that many of these tools in their standard configuration will NOT generate drawings acceptable by the USPTO. While I can't endorse any one particular product, many of my clients have had success using the CAD drafting tool RFFLOW (available from www.rff.com). This is a relatively inexpensive CAD tool that is very useful in generating drawings for computer and electronic related inventions, as well as organizing other types of non-computer drawings. This tool has particular use in generating complex flowcharts and system level diagrams associated with computer system/method and business method patents. As an aid in helping clients integrating this tool into their patent design methodology, I've developed an RFF Template for use with this product. The combination of this CAD tool and the provided template can provide an acceptable USPTO drawing that also has an aesthetic and appealing look and feel.
In addition to CAD drafting tools such as RFFLOW, I have found the Windows screen capture/image editing tool HyperSnap-DX (available from
General Drawing Guidelines
For those inventors wishing to generate their own drawings, the following general guidelines will be of use:
The above described general guidelines can be seen in the following example drawing:
Here the general principles of drawing numbering are illustrated. Note the invention elements associated with FIG. 3 all begin with "03" callout numbers. With respect to generation of flowcharts and the like, the following diagram may be of use as a general guide:
Here each major system flowchart block begins on a separate page, with the flow injection node labeled as step 00 ("0600") and each step of the method/process individually labeled in sequential order, starting with step "01". In this fashion it is a simple process to convert the flowchart to a step method claim by copying the flowchart text to a document editor and then tagging each line with sequential numbering.
Note that in some circumstances blocks within a flowchart may reference procedures which in turn must be fully described in additional separate flowchart sheets. For example:
Here the processes (1707) and (1708) will be more fully described in an additional flowchart.
Kevin Mark Klughart
Registered Patent Attorney, USPTO
3825 Leisure Lane, Denton, TX 76210-5589
tel: 800-353-1211 / 940-320-0580 - fax 940-320-0581