Machine Design

A better way to solve engineering problems.

TRIZ, a problem-solving technique for engineers, starts by breakingup problems into simpler components then applies several inventiveprinciples and otherresources to it.

 It often helps generate unexpected solutions that involve fewer design tradeoffs than traditional problem-solving, methods and sometimes no tradeoffs at all. The method also has a short learning curve.

The pages that follow and those to be added in the next few months will contain a range of examples that illustrate several of the software's inventive principles. The examples were written by Alla Zusman and Boris Zlotin, TRIZ experts with Ideation International Inc., in Southfield, Mich.

An intro to Triz
Since the beginning of the 20th century, experts have provided a range of problem-solving guides. Collectively, the recommendations are a hodgepodge of ideas. Their success has been inconsistent.

Greater success has come by applying more recent innovation tools. The first set of inventive principles to prove consistently useful was developed by Genrich Altshuller in the 1950s and 60s. Altshuller analyzed thousands of inventions documented in patents throughout the world, and selected those that represented the repeated application of the same principles. He recognized that the same fundamental problem had been addressed by a number of inventions in different areas of technology. In this introduction, we examine three inventive principles discovered by Altshuller that he called Segmentation, Inversion, and Prior Action.

In a nutshell, this principle suggests fragmenting a components or part into two or more pieces to make it flexible or adjustable. Here are several examples from different fields:

Snow depth can be measured by reading it off a pole or ruler pounded vertically into the ground. However, the pole is susceptible to damage by an avalanche.

One solution is to segment or break the meter beforehand by incorporating a spring-loaded hinge into it to make it bendable or flexible. Instead of resisting avalanches, the spring hinged meter bends with the snow, later returning to its previous position.

Invention 1. An avalanche-resistant meter
Invention 2. A filter made of ferromagnetic granules

To clean a hot gas of nonmagnetic dust, the flow was sent through a multi-layer package of metallic cloth. However, the filter was difficult to clean.

A proposed solution is a filter consisting of ferromagnetic granules held together by a magnetic field. When the magnetic field is switched off, the filter collapses making it easier to clean.

It can be difficult to grip workpieces with complex shapes using an ordinary vise.

It's much easier with a vise whose jaws are composed of several hard bushings. Each bushing is free to move horizontally conforming to the shape of the workpiece.

Invention 3. Gripping workpieces of complex shape
Invention 4. An antenna made with beads

Radio transmitters in cars may require long antennas. They can be damaged, for example, by just driving the car into a garage.

To prevent damage, a long antenna can be made from cylindrical metal beads strung on a wire. When the beads are loosely strung, they can be bundled up and compactly stored. When the wire is tightened, the beads form a long, flexible antenna.

Another effective inventive principle is Inversion, or doing something opposite to what is currently being done. For example:

Invention 5. Production of chocolate candies

A particular candy made of chocolate syrup in a chocolate bottle is made by first forming bottles of chocolate paste, then pouring thick chocolate syrup into them. It would be convenient to heat the syrup before it is poured, thus increasing its fluidity. However, hot syrup would melt the chocolate bottles.

An inversion solution is to freeze the syrup in molds shaped like the bottle's inner cavity. Then dip the frozen shape into a melted chocolate paste to form the bottle.

Invention 6. Branding with cold irons

Branding animals is usually done with hot irons. But it's a painful procedure that wounds the animal and creates a potential source of infection.

To reduce pain and infection from hot irons, cool the irons instead with liquid nitrogen. This does not wound animals but still permanently discolors hair or wool in the shape of the brand.

Prior Action
The third inventive principle, Prior Action, recommends performing a required action beforehand, either partially or completely. Another application of this principle is the prior placement of an object so that it can go into action from the most advantageous position. Several examples illustrate the idea:

Invention 7. Applying fertilizer at a set temperature

Fertilizer should be applied when soil is at an optimum temperature. This is difficult because large quantities of fertilizer cannot be applied instantaneously to large areas, and soil temperature constantly changes.

One solution packages the fertilizer in capsules that contain a liquefied gas. The capsules are spread in the Spring when the ground is still frozen. At the optimum temperature, expanding gas breaks the capsules and releases the fertilizer.

Invention 8. Preparing grass mixtures

One type of cattle feed consists of various cut grasses that are harvested and then mixed by special equipment. But producing the grass mixture by sowing the different grasses together yields a crop that is difficult to till. Furthermore, one grass species may suppress the others.

By sowing the grasses in narrow parallel strips and harvesting across the strips, the grasses will get mixed in the receiving bin of the mower, thereby needing no further processing.

Homework, sort of
Now that you've seen how the principles of segmentation, inversion, and prior action can be applied, it's time to put your new knowledge to use.

Assignment One
Apply one or more of the three principles to the following problems:

Problem 1. Shatter-proof glass windows
Early shatter-proof windshields on fighter aircraft had a serious defect: When a bullet or debris hit the window, a web of cracks would form and obstruct the pilot's vision. How might this damage be reduced?

Problem 2. Unloading frozen material
Unloading a large block of frozen material by defrosting it first can be expensive and slow. What other methods could you recommend?

Problem 3. Removing insulation coatings
Some metallic surfaces must be protected with a thick coat of insulating material. But removing the coating later can be difficult and time consuming. How can the insulation be removed more easily?

Assignment Two
Alt Shuller culled forty innovative principles were culled from among thousands of inventions. Some principles are universal and can be applied toward problems of any type, technical and non-technical. Describe one or more situations in which non-technical problems were solved by applying one of the three principles described in this lesson.

Solutions, comments and questions may be posted on the Bulletin Board at We'll also post answers for these problems in this space next month.

For further reading:
Learn more about innovation principles at the Ideation Web site ( or from the following texts:

Ideation Methodology course material: Introduction to the Ideation Methodology , Detroit, Michigan: Ideation International Inc., 1995.

Altshuller, Genrich. And Suddenly the Inventor Appeared: TRIZ, the Theory of Inventive Problem Solving, Translated by Lev Shulyak. Worcester, Massachusetts: Technical Innovation Center, 1996.

Kaplan, Stan. An Introduction to TRIZ, the Russian Theory of Inventive Problem Solving, Ideation International Inc., 1996.

Altshuller, Genrich. 40 Principles: TRIZ Keys to Technical Innovation, Translated and edited by Lev Shulyak and Steven Rodman. Worcester, Massachusetts: Technical Innovation Center, 1997.

Clarke, Dana W., Sr. TRIZ: Through the Eyes of an American TRIZ Specialist. Detroit, Michigan: Ideation International Inc., 1997.

Terninko, John, Alla Zusman, and Boris Zlotin. Systematic Innovation: An Introduction to TRIZ (Theory of Inventing Problem Solving), CRC Press LLC, 1998.

Altshuller, Genrich. The Innovation Algorithm, Translated and edited by Lev Shulyak and Steven Rodman. Worcester, Massachusetts: Technical Innovation Center, 1999.

TAGS: Archive
Hide comments


  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.