"Invention on Demand," Feature Article, November 2005

engineering management

invention on demand

A system lays down tools for creative problem-solving and product design.

by Jack Hipple

Consider the humble toothbrush. Its engineering has really changed in the last 50 years. There used to be one simple type—a rigid handle with bristles exactly the same length and stiffness. It was easy to make.

Then along came brushes with different handle lengths to suit adults and children. Then dentists realized that soft bristles are better for the gums. People have different-size mouths that can make it difficult to reach all the way back to the molars without discomfort, so along came flexible joints in the handles.

Those soft bristles were still great for the gums, but harder bristles could help dislodge stubborn food particles from teeth, so toothbrushes were designed that had soft bristles on the outside and stiffer bristles inside. There was a limit to how many times you would move the brush up and down before you just got tired of brushing, so an electric motor was added that increased the number of strokes without any additional effort. Many people took toothbrushes on trips and forgot toothpaste, so a toothbrush with the toothpaste stored in the handle came along.

Today, we have sonic toothbrushes whose frequency is much higher than any motor's.

In the meantime, oral care products, from tongue-scrapers to dental tape, were introduced to be used in addition to the toothbrush. Toothpastes were modified to improve the overall effectiveness of the oral care system.

All the changes were in reaction to a customer need or to new medical information. What's more, all the changes were predictable.

They broadly illustrate the principles of TRIZ, a structured problem-solving and product-design method. TRIZ stands for a Russian phrase that can translate as "Theory of Solving Inventive Problems" or "Theory of Solving Problems Inventively." The theory takes the position that creativity and innovation are not primarily intuitive processes, but are sciences and can be studied and learned, and therefore managed. Furthermore, an understanding of the principles behind TRIZ can help predict, in a broad sense, where a business or market is going.

About 50 years ago, a Russian patent examiner, Genrich Altshuller, refused to accept the opinion that invention, alone among technical disciplines, was not susceptible to scientific and structured analysis. He was in his early 20s, already had patents under his belt, and had been hired by the Soviet Navy as a patent examiner. He studied several hundred thousand patents to find the truly inventive ones, from which he was able to map and correlate the patterns of invention.

Patterns of Technology

Altshuller identified a number of inventive principles and also discerned patterns of technological evolution. He regarded these ideas as generic principles that could be used not only to solve problems in product design, but also to forecast and plan product and business development. As people have continued to study the patent literature, they don't find much in the way of any new inventive principles, and the ratio of really breakthrough patents continues at less than 5 percent.

TRIZ began to migrate to the West after perestroika, partly because many of its proponents in the Soviet Union were frustrated at not being able to implement their technology in the private sector. The methodology is now in use by such companies as Motorola, Hewlett-Packard, Dow Chemical, S.C. Johnson, and United Technologies.

The evolution of the toothbrush embodies many of those principles and patterns.

For instance, Altshuller and his colleagues determined that a system or product improves over time as developers resolve contradictions and take advantage of new or overlooked resources. We wanted the bristles to be soft and hard, the handle to be rigid and flexible. We had all that unused space in the handle that could hold toothpaste. Electric motors became very tiny indeed.

The IntelliClean combines a Sonicare sonic toothbrush with liquid Crest toothpaste. Seen through TRIZ, it's a natural development of technology.

Systems and product elements evolve at different rates. At any given time, one part of a system or product has a limiting contradiction. The conflict between toothbrush size and mouth size was resolved first to allow children to brush effectively. The contradiction of rigid vs. flexible handles was partly resolved. So was the difference in needs between "gum bristles" and "teeth bristles."

At any one point in time, there is one most significant contradiction that catches our attention and resources. The handle, bristles, and energy supply are all different elements of the system. Their evolution and problems, in many
cases, can be independent of each other. The outstanding designer thinks about all elements at the same time.

Systems and products become more dynamic over time. The toothbrush has become more dynamic in a couple of ways. First, the handle was made flexible, and later, the energy source increased in dynamism from the slow frequency of the hand to that of an electric motor or a sonic vibrating system.

Systems evolve by the matching and mismatching of components and properties. In this instance, we are talking about the matching and mismatching of dynamic components to achieve a positive result. The mix of long soft bristles and short stiff ones is a beneficial mismatch. So are different tires and suspensions in the front and rear of cars for better handling. And a meeting of people of much different personalities and backgrounds is likely to generate diverse ideas and significant discussion. Some other combination—perhaps a short handle and very long bristles—may not be so beneficial. If properties are matched, we should look at mismatching and vice versa.

Systems and products oscillate between complexity and simplicity. The toothbrush and most mechanical systems used to be simple. Then they slowly became more complex as we added features to achieve additional objectives. We didn't want to just clean teeth, we wanted to exercise gums. We didn't want to just exercise gums, we wanted to remove plaque. Now we want the toothbrush to provide longer-term oral care. These additional functions are now performed by separate, added systems. TRIZ, meanwhile, identifies an opportunity for improvement in combining some of those systems to simplify the design.

Systems and products evolve toward a higher level of field use. Many complex systems progress along a predictable technological path—perhaps from mechanical to thermal, to chemical, to electromagnetic. The toothbrush was purely mechanical. Then we added a chemical field (toothpaste), and later a sonic or electronic field. What do you need to know to move to the next step? Have there been steps missed or that might provide niche opportunities?

Systems and products evolve toward a state of less human involvement. This principle is very familiar. We see it everywhere, from automated tellers to automatic bill-paying. There is certainly no reversal of the trend to automate in industry. Today, we only have to move the electronic toothbrush from place to place in our mouths and the system does the rest. But many systems involve manual labor, creating opportunity for error and taking time. After all, we still have to hold that brush for the right amount of time. Could we eliminate that human component by designing food additives that are oral-cleaning, possibly on a delayed basis? Could an oral implant dispense chemistry automatically to fight decay and remove plaque?

These and other principles of TRIZ can provide tools for methodical product development, and for rational management of engineering design departments. TRIZ often enters an organization when the manager starts asking questions: What are the available resources? What contradictions remain unresolved? It can bring focus to a team, and kick-start their invention.