NEW YORK -- It is lunch hour in Manhattan, not that you would notice from the scant few diners perched on the cracked vinyl stools in the Chock Full o' Nuts restaurant. A sign in the window reassures doubters: "Yes, We're Open."

But not for long.

At the end of September, the lunch counter at Broadway and 35th Street in Manhattan's Herald Square will close forever, leaving but one Chock Full o' Nuts restaurant in a city where the chain once was an institution.

"They said the lease is up and they're not going to renew it," said Katie Jamison, the restaurant's manager. She has worked for 15 years for the chain she simply calls Chock. "It's sad, but what can you do, right?"

Chock Full o' Nuts, which began as a Times Square nut stand in 1922, reached its peak in the 1960s, when the chain boasted about 80 restaurants, some as far south as Philadelphia.

Chock's hallmark was "heavenly" coffee -- the company began retailing the blend in 1953 -- and its inexpensive, prepared food that was untouched by hands. All of the food was prepared in a commissary in Secaucus, N.J., where the cooks used tongs to assemble sandwiches.

"This was the original fast food, in a way," said Susan Siegle, a financial officer for a dress manufacturer who stopped by the other day to order a nutty cheese sandwich -- cream cheese and chopped nuts on dark raisin bread wrapped in plain, waxed paper.

Chock Full o' Nuts restaurants, where for a long time the waitresses were not allowed to take tips, are dying unceremoniously. The lease on the remaining restaurant, at 41st Street and Madison Avenue, will expire in the next two years. There are no plans to renew it.

It will be a pitiful end to a business that reflected the quirkiness of its fastidious founder, William Black, a philanthropist who lied so much about his origins that even he was unsure of his age when he died in 1983. The obituaries said he was 80.

"The restaurants were really going down hill," said one of his three daughters, Barbara Jane Kennedy, 54, who lives in Manhattan. "I passed a few of them several years ago, and they were so dirty. My father was almost nutty about cleanliness."

"It is sad, but it's kind of inevitable," said Black's eldest daughter, Willy Werby, 58, of Hillsborough, Calif. "There was no one to take over."

The demise of the coffee shops is the result of a typical corporate evolution, in which the modern entity no longer bears any resemblance to the original business. There still is a Chock Full o' Nuts Inc. -- it is a publicly traded coffee company that had more than $250 million in sales last year. But it discarded the restaurants after Black died.

Black earned a degree in engineering. But he found opportunity in the long lines that formed outside a discount theater-ticket outlet in Times Square. He set up a nut stand, and within a decade, he owned 18 Chock Full o' Nuts restaurants.

During the Depression, nuts became expensive, so Black converted the stands into lunch counters that specialized in cheap, quick meals.

Eventually the retail coffee business overtook the restaurants in sales. A younger generation that preferred hamburgers and pizza had little desire to patronize lunch counters where waitresses who wore hairnets served nutty cheese sandwiches, frankfurters and pea soup.

"He just didn't adapt," said Werby.

As the leases expired on the restaurants, the company shut them down, one by one.

After Black died, no one in his family had any connection to the business. His physician, Leon Pordy, took over as chairman of the company.

Chock Full o' Nuts Inc. sold its remaining 17 restaurants to Riese Brothers Inc., a management firm that operates 320 franchise restaurants in the New York area, ranging from Roy Rogers to Houlihan's.

"It was more of a real estate deal than a restaurant deal," said Joseph A. Breslin, executive vice president of the coffee company.

Riese had little interest in operating Chock Full o' Nuts restaurants, said Vincent M. McCann, the company's chief operating officer.

"I think there's a curve to any business, and the real secret to success is maintaining the upside of that curve as long as you can," said McCann. Chock Full o' Nuts was "well past that point."