The Evolution of Useful Things: How Everyday Artifacts-From Forks and Pins to Paper Clips and Zippers-Came to Be as They Are.

by Henry Petroski

  There are other alternatives to the conventional screw head, and Rabinow calls one, the Phillips-head screw, a “prettier design.” He notes that it certainly reduces the probability of the screwdriver’s slipping but, like most evolutionary designs, for every advantage it has over the traditional design it seems to have a disadvantage of its own. In the case of the Phillips-head screw, which may also have some aesthetic advantages over the common screw head, the Phillips-head screwdriver must be more closely matched to the screw head than is the case with the traditional design, and when the screwdriver gets worn with use it is much harder to sharpen than a conventional one. Rabinow displays his creativity by demonstrating how he can imagine new screw heads that eliminate some of the shortcomings of the Phillips-head screw.

  He observes that there are screws made with square and hexagonal depressions in their heads, with matching screwdrivers or wrenches. He seems to prefer the design with the square depression, because “it is easy to sharpen the screwdriver and it’s very positive.” But of course, as Rabinow observes, “in all of these designs, a flat screwdriver of the right width can be used for unauthorized removal of a screw.” Hence he asks if one can redesign the screw head so that the screws will stay put. The inventor’s challenge is then: “Can one design a slot or a depression in the head of a screw that cannot be driven by a flat screwdriver of any width?” Rabinow would no doubt have hired on the spot any interviewee who responded in any way close to the master’s solution:

  If you make a triangular depression with sides in the shape of three arcs, where each point of the triangle is the center of curvature of the opposite arc, you have a triangular hole that can be driven with a specially shaped screwdriver, but not by any flat screwdriver. If you insert a flat blade, the blade will pivot at each corner and slide over the opposite curved surface, hit the next corner and slide again, and so on. Such a screw should look very attractive and would be very difficult to open without the proper tool.

  Rabinow admits that he does not know whether this idea is new, because he has not looked in the Patent Office files. He has, however, searched those files to check many a potential solution to problems generated through more than pedagogical or evaluative motives, and he no doubt has observed how explicitly those files contain statements to support the hypothesis that artifacts evolve by the incremental elimination of their defects.

  David Pye uses the related example of nuts and bolts to articulate principles relating to the evolution of artifacts:

  When hexagon nuts and hexagon heads superseded the old square ones on bolts, it must have been greater convenience in use which argued for the change: to turn a square nut in an awkward place one may need two different spanners.… From that time on for many years hexagon bolts were one of the normal features of “modern engineering.” By means of them alone if by nothing else, the layman of the early nineteenth century could distinguish between one of the new engines and the old ones of Watt’s time.

  Nearly always when a new feature appears it has earned its place by defeating an older one.

  But, just as diametrically slotted screw heads have not been totally displaced by Phillips-head ones, so square bolts did not become extinct. There remained applications where the wrench or spanner did not have to fit into an awkward place, and the square nut maintained the advantage of economy over the hexagonal. Erector sets, which sought a high-tech image in the early twentieth century but presented many an awkward space for even a child’s hand and toy wrench, still came with slotted bolts and square nuts, as did the contemporary British Meccano sets. Hexagons did have the disadvantage of being too easily rounded into useless circular nuts.

  “So long as there are inconveniences and discomforts in our ordinary way of life, so long will there be inventors striving to improve matters.” So reads the introduction to a collection of descriptions of short-lived products taken from the patent files of the century beginning in 1849. The pages of Scientific American, founded a year earlier; the Illustrated London News, dating from the same period; or a host of contemporaneous popular publications could serve just as well to chronicle the drive of inventors. And the catalogues of world’s fairs, descendants of the Great Exhibition of the Works of Industry of All Nations, held in London in 1851, provide further evidence of the era of great independent inventors. However, a glance at the “50 and 100 Years Ago” page of any current issue of Scientific American shows rather dramatically that perception of things certainly did change, at least in the pages of that magazine, between the early 1890s and the early 1940s. Whereas one hundred years ago there was frequently illustrated a curious gadget or device that improved on existing gadgets and devices, the news of fifty years ago is principally of scientific theories and discoveries, knowledge of which an inventor-manager like Rabinow might find interesting but not necessarily having in itself the makings of a creative invention. By World War II, we seem to have come to take new gadgets for granted or relied upon advertising to inform us of what was new. Whereas our great-grandparents apparently found the latest improvement on the fountain pen or the bicycle of intellectual interest, most people in our generation take only a commercial and utilitarian view of such things. Thus the science-and-technology sections in today’s newspapers and magazines will generally print pages of jargon from the medical and physical sciences but give us little of the thoughts or products of engineers or inventors.

  Invention is not dead, however, nor is what drives inventors today any different from what did so in years past. The link between the evolution of artifacts and the practice of invention is timeless, even if it has by and large come to take a less visible role in society. What drives today’s inventors is the same thing that drove nineteenth-century inventors to put lightning rods on umbrellas or to make the umbrellas integral with headgear so as to free the hands of their wearers.

  Whether self-generated or heard from others, whether couched in crass terms of coming up with a million-dollar idea or in Utopian dreams of wasteless societies, whether expressed in Anglo-Saxon concretions or in Latinate, polysyllabic abstractions, dissatisfaction with existing artifacts is at the core of all invention and hence all changes in made things. Thus Edwin Land was prompted to invent the Polaroid instant camera by his three-year-old daughter’s question as to why she could not see at once a picture he had taken of her. The innocent “Why not?” articulated a shortcoming of existing cameras that Land was determined to remove.

  In his classic History of Mechanical Inventions, Abbott Payson Usher spoke of the same process of invention in the following, more academic terms:

  Invention finds its distinctive feature in the constructive assimilation of preexisting elements into new syntheses, new patterns, or new configurations of behavior.… Invention thus establishes relationships that did not previously exist. In its barest essence, the element of innovation lies in the completion of an incomplete pattern of behavior or in the improvement of a pattern that was unsatisfactory and inadequate.

  Seasoned inventors seem clearly to understand and operate under the generalization contained in Usher’s remarks, recognizing that it is problems with existing patterns of doing things or problems with the things themselves that provide opportunities for invention—for new, improved patterns.

  Whether the new and improved are patented can be a matter of taste or judgment, and some of the most prolific of inventors and engineers—such as Isambard Kingdom Brunei, designer of the Great Western Railway and the Great Eastern steamship—have been strong opponents of the patent system, which they felt stifled innovation. In 1851 Brunei wrote to the Select Committee of the House of Lords on the Patent Laws:

  I believe that the most useful and novel inventions and improvements of the present day are mere progressive steps in a highly wrought and highly advanced system suggested by, and dependent on, other previous steps, their whole value and the means of their application probably dependent on the success of some or many other inventions, some old, some new.

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sp; Because Brunei believed that “really good improvements are not the result of inspiration,” but “more or less the results of an observing mind, brought to bear upon circumstances as they arise,” he believed that “most good things are being thought of by many persons at the same time.” The patent system obstructs real progress, according to Brunei, because when someone “thinks he has invented something, he immediately dreams of a patent, and of a fortune to be made by it.” Brunei continued,

  If he is a rich man he loses his money, and no great harm is done; but if he is a workman, and a poor man, his thoughts are divided between scheming at his machine in secret, and scheming at the mode of raising money to carry it out. He does not consult his fellow-workmen, or men engaged in the same pursuits, as to whether the same thing had ever been tried, why it had failed, what are the difficulties, or (what is most probable) whether something better is not already known, and waiting only the demand.

  Other inventors and engineers, such as Henry Bessemer, who was unabashedly interested in fortune, have not deplored the patent system, but have made ad hoc judgments about what to patent. While Bessemer did collect a host of patents throughout his life, notably those protecting his iron-smelting and steel-making processes, he deliberately chose not to patent his method for making bronze powder. He kept this very lucrative business venture secret for about thirty-five years by carrying it out in a secure factory and by employing only trusted relatives in key positions. By Bessemer’s own account, the profits “provided the funds demanded by the ceaseless activity” of his “inventive faculties.”

  While any theory of the evolution of artifacts must be independent of whether the objects of its principles are patented or not, it is obviously easier to find documentation for testing hypotheses in the formal literature of technology than in the trade secrets of family businesses. Indeed, patent files, while by no means a complete record of artifactual evolution, do provide a store of primary sources and case studies. Even the secondary literature of patents and the patent process provides a wealth of insight into the nature of invention and evolution in technology.

  Patent It Yourself, a book by patent attorney David Pressman, is more for the “first-time inventor” than the old hand or the theorist, and so it deals on a rather elemental level with much of the process of inventing and patenting. In an early chapter on “the science and magic of inventing,” which Pressman admits the experienced or corporate inventor can skip, the process of invention is described as a “two-step procedure: (1) recognizing a problem, and (2) fashioning a solution.”

  The trick is in taking the first step, which Pressman recognizes can often amount to “about ninety percent of the act of conceiving the invention.” His advice to the novice is to ferret out problem areas:

  This can often be done by paying close attention to your daily activities. How do you or others perform tasks? What problems do you encounter and how do you solve them? … Ask yourself if something can’t be done more easily, cheaply, simply, or reliably, if it can’t be made lighter, quicker, stronger, etc.

  Later on in his primer, Pressman addresses the question of the commercial promise of an invention conceived to solve a problem, and he advises the reader: “You should not spend significant time or money on your creation until you have thoroughly evaluated it for commercial potential, including considering all of its advantages and disadvantages.” He presents a list comprising a “positive and negative factors evaluation,” which essentially is a means of establishing whether an invention is indeed a net improvement over what is now being used. In other words, does the invention promise to perform overall better than whatever it is expected to supersede? The problem with such an evaluation is that the positive and negative factors must be weighed, and this involves subjective judgments. For example, Pressman’s list contains forty-four factors, ranging from cost, weight, and size to market dependence, difficulty of distribution, and service requirements. The net result of such a survey obviously depends very greatly on how accurately and honestly the relative importance of such disparate factors can be determined. It is clearly not an easy task for a biased inventor to evaluate the fruits of his or her own imagination.

  Regardless of the genesis or potential of an invention, the question of “prior art” must be addressed if a patent is sought. This is parlance for whatever knowledge is considered obvious to those most familiar with the area in which a problem is being solved. Thus, to be patentable, an inventor’s idea must somehow not be merely an obvious way to improve something. In his book, Jacob Rabinow frequently refers to “the art” in relating stories about how he proceeded with various of his inventions. In one instance in the 1950s, after he had left the National Bureau of Standards to start his own firm, Rabinow was asked by a radio-equipment manufacturer to devise an accurate push-button tuner for an FM radio receiver or a TV set, both of which at the time were relatively new consumer products and were touchy to tune. The inventor had long had an interest in radios and was cognizant of developments in the field. He relates how he was familiar with some of the original tuners, which were as large as the receiver they controlled, and how erratic changes in volume often accompanied their use. He summarizes his expertise with the phrase “I knew the art.” Thus Rabinow realized the advantages and disadvantages of existing tuners, which were no doubt obvious to many people working on or with tuners, and he knew how those disadvantages were dealt with. But correcting these faults significantly at any stage in the development of tuners was not so obvious; otherwise, that would have been done for the competitive advantage it would have given to radio and television manufacturers.

  By “knowing the art,” Rabinow could anticipate, as he worked on the problem of an improved tuner, what features he might incorporate into it that would later make convincing patent claims regarding the prior art. For example, in a departure from the familiar push-button tuner, he devised a pull-button one in which, when pulled out, the conical buttons could also serve as knobs to fine-tune the stations selected. Rabinow’s tuner was patented, but the commissioning company did not like the idea of a product’s being too different from what other companies were producing: “No one uses pull buttons; everybody uses push buttons.” The inventor responded, no doubt precisely because he knew the art, “Well, if you’re going to make push buttons, you might as well use the stuff that’s on the market. There’s nothing I could do that’s any better.” In other words, he knew the state-of-the-art tuner’s shortcomings, but he could not see his way to removing them without striking out in new directions.

  For the inventor less experienced than Rabinow, Pressman summarizes the way in which the prior art is treated in a patent application and how the objects and advantages of an invention are conventionally presented to the patent examiners. He explains that the form in an application is first to discuss the prior art, then to present the objects and advantages of the invention, its operation, and finally the claims being made for the invention. Pressman admits that there is a lot of redundancy in a patent application and defends it as effective communication of this kind: “first you tell ’em what you’re going to tell ’em, then you tell ’em, then you tell ’em what you’ve told ’em.” And what is told mostly in a patent application is what’s wrong with existing things. The patent attorney’s advice makes this clear:

  Discuss how the problem to which your invention is directed was approached previously …, and then list all the disadvantages of the old ways of doing it. [List again in the objects-and-advantages section] all the things your invention accomplishes and its advantages over the prior art.… Include all of the positive factors of your invention … and all the disadvantages of the prior art.… At the end of this section, add a catch-all paragraph reading as follows: “Further objects and advantages of my invention will become apparent from a consideration of the drawings and ensuing description of it.” … [And] the objects are effectively repeated again (a third time!) in the concluding paragraph of the specification.

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nbsp; Even if one can endure the tedium of writing out a patent application, there are often even more frustrating aspects to bringing an invention to fruition and commercial success. Although 90 percent of the creative problem of invention may be in problem identification, one does not necessarily have an easy time of it thereafter. An inventor is never home free just because a good problem is identified, for “fashioning a solution,” in the sense of conceiving a possible way to alleviate the problem, may involve considerable effort. Thomas Edison was not alone in recognizing problems with candles and gas for lighting, and he conceived but one version of the electric light bulb. (British inventors had long experimented with electric lights before Joseph Swan was granted an English patent for a carbon-filament lamp in 1878, the year before Edison received an American patent for his.) Regardless of priority, Edison’s idea for a light bulb was his “inspiration.” He then had to test thousands of materials before finding a successful bulb filament to make a practicable model of his idea. Next he had to go through the process of patenting it and, finally, setting up the infrastructure to distribute and sell his invention. Only then was the electric light bulb truly a successful innovation, and it was the long process of going from idea to acceptable product that Edison referred to as the “perspiration” part. Thus when the Wizard of Menlo Park called invention 10 percent inspiration and 90 percent perspiration, he was speaking not only about the creative act of inventing but also about the whole inventive process needed to bring more than intellectual success. Edison warned against discouragement during the perspiration phase in the following way, reminding us that we get things to work by the successive removal of bugs: