The Arizona Republic, Tom Tingle, Associated Press
In this photo taken on Tuesday, Aug. 21, 2012, Joseph R. Pompa, talks about his parents, Joseph and Eva Pompa, at La Perla Mexican Restaurant in Glendale, Ariz. The elder Pompa invented a taco making machine and even had a patent.

GLENDALE, Ariz. — The artifact is buried amid boxes in a cinder-block storage building down the street from La Perla Mexican restaurant in Glendale, where it was first used.

The machine was always important to the Pompa family, operators of one of metro Phoenix's original Mexican restaurants. But mainly for its practical application, which was to produce fresh taco shells.

For the children who would go on to work in the family restaurant, the device was something their father, Joseph Peralta Pompa, had pieced together from scrap airplane parts in his shed in the 1940s.

They knew running it could be a hot, greasy chore. They also knew his invention allowed La Perla workers to fry freshly made taco shells faster than one at a time.

But they certainly had no idea it would become a little piece of history.

Said son Joseph "Butch" Pompa, 67: "We all knew about the invention, but we never focused on it."

But it caught the attention of University of Minnesota historian and author Jeffrey Pilcher, who said, "This is the sort of thing they could put in the Smithsonian."

Of course to do that, the Pompas would first have to dig it out. It is stored along with boxes of the senior Pompa's papers dating to the restaurant's opening in 1946. Those documents might contain a clue as to what motivated the owner of a Mexican cafe to go so far as to enlist an attorney and draw up the complicated language necessary to secure a government patent on his invention.

All this for a device that handles the simple task of folding a tortilla in half, dipping it in oil and producing a now-universally recognized food.

The family discovered its place in history only after two new books that focus on the rise of Mexican food in the United States. "Taco USA: How Mexican Food Conquered America," by Gustavo Arellano, was published in April; Pilcher's "Planet Taco: A Global History of Mexican Food" comes out next month.

The last of the three original machines the senior Pompa made gave out about six years ago. Butch Pompa had a replica made out of stainless steel because his restaurant needed to continue making the taco shells the way his dad did.

His dad was the founder of La Perla and holder of U.S. Patent No. 2,570,374, secured in 1951 for a "machine for frying tortillas."

"Can you imagine the creativity that went into that?" Butch Pompa said, watching the contraption get lowered into bubbling oil, creating two dozen crisp taco shells in a matter of seconds. "I consider him a genius."

Joseph P. Pompa grew up in Pearce, a small town in southeastern Arizona. His own father abandoned the family when he was a boy, and his mother raised the family with help from her sisters.

At around age 14, the elder Pompa got angry when his cousins, nieces and nephews teased him about how their mothers were helping his mother raise the family. He vowed his family would never depend on anyone again. He quit school, left for Prescott and got a job on the railroad. Then, he moved to Jerome and worked in the mines, said Joanne Pompa Sandhagen, 70, one of his four children.

"He was at bottom of the mine, just dirty work," she said. While working in Jerome, he met Eva Macias, who lived in nearby Clarkdale. She would become his wife.

After a day working at the mine, Joseph studied electrical engineering through correspondence school. "My mother would complain," Joanne said, saying things like: "We could be going out, and you're spending all this money on correspondence school."

But with his degree, he got a job at the air-research division of Goodyear. "The first check from Goodyear research, he handed it to her," Joanne said, as if to show her what all the work was for.

Joseph invested in real estate and started some side businesses, including a now-shuttered bar in El Mirage called El Rio and a Mexican restaurant in downtown Glendale. He put his wife in charge of La Perla, which came from his nickname for her.

La Perla started with a simple menu: enchiladas, burros, tacos and tostadas in varying combinations. The No. 2 combo, a taco, tostada and rice, cost $1. But the taco and tostada shells proved labor-intensive.

An employee had to hold each tortilla closed using tongs, baby-sitting it as it fried in oil. As Joseph explained in his patent application in 1949: "Heretofore tortillas were fried by hand in deep fat and held in position by hand as they hardened and turned crisp."

Joseph figured there had to be a quicker, easier way. He went to his shed, where his son said he was always tinkering with gadgets, and emerged with some prototypes. His son Butch would play with and eventually bust most of them. But the one that worked was made of lightweight scrap airplane metal. The device was a rectangular frame that held rounded humps. Tortillas could be draped over them and be held in place with a metal cover.

"These formers hold the tortillas in the correct position for deep frying," Joseph's patent application read. The whole contraption could then be dipped into hot oil. After a few seconds, the rack could be lifted out, allowing the grease to drain. Then, the cover could be opened and the shells removed, two dozen at a time.

Butch called the machine a blessing, allowing the restaurant to quickly make a daily supply of fresh shells and resisting any temptation to move to prepackaged shells.

The taco-shell maker was not the only patent Joseph filed. In 1950, he filed a patent on a tostada-shell maker, a contraption that held the tortillas vertically in small slots. Like the shell maker, it could be dropped in frying oil until the tortillas crisped.

While both machines were boons to La Perla, the Pompa family does not know if their father tried to mass-market his invention or sell it to other restaurants.

Filing a patent requires pages of intricate detailed description in legal language, as well as research into similar inventions. In the late 1940s, the process might have included hiring someone in Washington, D.C., to sort through similar patents in person, said Pacer Udall, a Tempe patent attorney.

Udall said people typically don't apply for patents expecting to make a mint. Some do so out of personal pride alone.

"It's that American spirit," he said. "Always pushing, going further. ... That entrepreneurial spirit to move and make things better."

But the main reason is to stop competitors from using an invention. "It allows you to realize a return on your investment," Udall said. "The only downside is: No one can enforce those rights but you."

Joseph Pompa died in 1961 at age 47. In his last few years, his family remembers him meeting with lawyers, and Butch wonders if he was trying to enforce his patent. Maybe he saw similar machines and thought they were violating his rights.

"It sounds logical," Butch said. His father, a former boxer, was never one to shy away from a fight. Joseph boxed during the time when punches to the back were allowed. He died of kidney disease.

Eva Pompa died in 1973, and Butch took over as manager. In the years since, the restaurant has served not only as a gathering place but also as a high-school or college job for all the family's grandchildren and great-grandchildren.

As Joanne enjoyed a lunch of enchiladas during an interview, she kept pausing to wave and greet customers she recognized.

Her father didn't patent the longtime family Mexican restaurant, but he did create one.

"Life has been beautiful because of that man," she said of her father. "What he created for us is a just a great heritage and a great life."

Information from: The Arizona Republic,