Patent Drawings: When and Where to Use Hatching and Shading

As per the U.S. Patent and Trademark Office (USPTO), it is essential to attach drawings to a patent application if they enhance the understanding of an invention’s subject matter. When appended to the application, drawings should display every feature of the invention mentioned in the claims. Among the various techniques used in preparing drawings, hatching is the most crucial one. Illustrators employ this technique to create shading effects using closely spaced parallel lines.

In the following article, we cover when and where you need to use hatching in patent drawings.

Relevance of Hatching and Shading Techniques

Patent drawings are illustrations that help in better understanding the inventions. Several drawings along with the detailed description make a complete patent application that is acceptable to the patent office.

Although patent illustrators are careful while creating drawings, sometimes these illustrations are still rejected. One of the most common reasons for this is direct production, i.e., preparing colored drawings or images that are not allowed by most patent offices. Complex graphs with multiple curves, bars with different colors, and even sectioned parts that are not presented correctly lead to such drawing rejections. Besides these, low-quality drawings that make it difficult to differentiate between the shapes of views also lead to drawing rejections.

To  distinguish the surfaces and material of the parts and understand the appearance of the part, you can use hatching and shading techniques. These techniques help in differentiating the color as well as the shape of an invention’s parts.

What is Hatching?

Hatching is a technique that can be used in a patent drawing to show the cross-sections, materials, textures and shadows. It is essentially used to create tonal effects by making parallel lines, oblique lines, dots and different patterns.

When and Where to Use Hatching?

Although hatching technique can be used in both utility and design patent drawings, it is mostly used in utility drawings. In case of design drawings, it is used to show texture.

In Utility Drawings
  • For Cross-Sectional Views – The purpose of showing hatching is to tell the examiner as to where exactly the imaginary cutting plane cuts the material of the object as it slices/passes through the object.If you do not show the cross-section view with a proper hatch pattern, then it can cause confusion and lead to a rejection. Read more for information on rejections based on hatch patterns.

Fig. 1: Incorrect Cross-Section View                  Fig. 2: Correct Cross-Section View Using Hatch Pattern

Let us consider the two figures (above) to understand the use of hatching in utility drawings. In Fig. 1, the cross-sectional view has no hatching. As a result, the examiner can be confused whether this is a cross-sectional view or the actual shape of a complete part. While Fig. 2 uses a hatch pattern, which is the correct way of showing the cross-sectional view in utility drawings.

  • For Denoting Different Colors – In utility patent drawings, you cannot use colored drawings as per the patent rules. In such cases, you should use hatch patterns to show the different colors, especially in graphs.
                             Fig.3: Incorrect Drawing                     Fig.4: Correct Drawing Using Hatch Pattern

To understand the use of hatch patterns in graphs within utility drawings, let us consider the figures shown above. In Fig. 3, the graph has different colours to display the statistics. This drawing is bound to be rejected as colored images/drawings are not allowed as per the patent rules. While in Fig. 4, the different angles or types of hatches are used for showing the statistics and their respective colors. This is the correct way of showing a coloured graph in utility drawings.

In Design Drawings

You can use hatching for showing the texture or the material of the product in design drawings. Basically, you can use different types of hatches to show the texture of fabric such as velcro and leather. For instance, in Fig. 5, hatching shows the cloth like material of a bag.

Fig.5: Hatching to Show the Texture of a Bag

What is Shading?

Shading is a technique that is used to visually define an object for better understanding of an ornamental design. Like we use shading for showing the depth of a part, circular shapes, 3D effects in 2D designs, contours, etc. The right shading in patent illustrations eliminates the chances of confusion and rejection by patent examiners.

In the next section, we discuss the two main types of shading in patent drawings – stippled and linear.

Types of Shading and their Uses

  • Linear Shading

Linear Shading can be used to show surfaces in patent drawings. This type of shading can be flat, curved, or tapered. The line weight (line thickness) of the shading line should be less than the thick line of the product. The thick line is the outermost line or curvature of the part having line weight or thickness greater than the rest of the lines.

Fig.6: Different Types of Linear Shading in a Product
  • Stippled Shading

Stippling can be defined as making a pattern that simulates varying degrees of shading with the help of tiny dots. This type of shading mostly uses many different points to create the impression of an object or its texture. It reduces the negative space that can make a surface appear more shadowy, more textured, or closer to the viewer.

Fig.7: Stippling in a Leather Bag

Hatching Patterns Accepted by the USPTO

You can use different hatching patterns for different materials such as metal, fiber, liquid, concrete, cloth, adhesives, and rubber in patent drawings. Some of the patterns that are accepted or followed by the USPTO are given below:

Fig.8: USPTO Approved Hatching Patterns for Patent Drawings (Source: USPTO)

Conclusion

Since patent drawings are key to ensuring the success of a patent application, it is essential to create them carefully. Among the various techniques used for preparing drawings, hatching and shading are the most significant ones. They not only enhance the quality of patent drawings but also help the examiner to understand the invention better.

If you have been searching for high-quality patent drawings services, look no further. Sagacious IP’s Patent Drawings/Illustrations service can help you create both utility and design patent drawings that can effectively present your invention on paper. Click here to learn more about this service.

  • Rupesh Vajpayee (Illustration) and the Editorial Team

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