1949 | The "Ripple" Crepe Sole
Source: The Indianapolis News | October 7, 1949

The ripple sole is a smooth moulded rubber wrap on a conventional crepe sole, with an added feature Western buckle. Two fall colours. 
The Salem NewsSeptember 26, 1949

The term "Ripple sole" was already out there since the early 40's and usually meant ripple-edged sole used both for men's and women's and later for kids' (above image). However, retired Detroit shoe salesman Nathan Hack had a different idea in mind when he though of it.

1952 | Rippling Walking
Army boots & lady's shoe
Source: The Daily Argus Leader (Sioux Falls, South Dakota) - April 24, 1952

Nathan Hack said his new "ripple sole" is the first new departure in footwear since Julius Caesar put heels on shoes to enable his soldiers to walk farther. "And that was 2000 years ago" he said. 
Hack, past president of the Detroit Shoe Retailers Association, said the ripple sole is made of a rubber-leather composition. It is attached beneath the regular sole and "lengthens each stride six inches more than ordinary shoes", Hack said. 
The ripple sole consists of a series of waves running from the front of the heel to the tip of the toe. As the body leans forward, each successive ripple gives way so that when a step is completed one has the feeling that he is walking downhill. 
Courier Post
April 19, 1951 (Camden, New Jersey)

1953 | First actual application of the Ripple Sole
Source: Dayton Daily News (July 11, 1953)

Hack stumbled upon the ripple sole with the help of Dr. Lawrence E. Morehouse while searching for a shoe to cut down the hazards of broken legs and ankles among paratroopers. Jumps tests were taken and the results were successful to a certain degree. Still, while walking, the testers reported a "walking on air" feeling and that gave the two inventors the idea to further experiment the sole for a different use.

The ripple sole absorbed shock, stored energy and then aided in lifting the foot for the next step ... The inventors believe ripple soles will prove a blessing for postmen and policemen and others who spend most of the day on their feet. 
"I think the ripple sole will find a place in athletic events too" said Hatch. "At least it will relieve the strain on million of pairs of feet". 
The Daily Argus Leader (Sioux Falls, South Dakota)
April 24, 1952

1953 | The Ripple Sole for athletic shoes
Source: The Daily Herald (December 25, 1953)

The Ripple Sole forerunner was a convalescent boot he gave on a royalty-free basis to the U.S. Army in 1944. Nathan Hack called it his "contributions to the war effort" and his way to pay back a debt he owns to Uncle Sam.

The Ripple Sole gained momentum when two national magazines (Colliers and The Reader's Digest) run extensive articles about Hack's invention. The applications in standard footwear became apparent so he patented his idea (assigned to the Ripple Sole Corp.) and licensed it domestically to Nashua's Beebe Rubber Co. (New Hampshire) at the end of 1955.

1952 | The Resilient Shoe Soles by Nathan Hack
Filed July 14, 1952 - Granted June 14, 1955
Source: Google Patents

1956 | The Coward Shoe
Source: Daily News - December 4, 1956

Adopted by many producers (Levy's, Naturalizers, Palizzio, Florsheim, Sandler of Boston...), the Ripple Sole became a success (The Ripple That Became a Tidal Wave) and starting from 1957 a "Ripple Sole Week" was held in Tucson and lasted until the early 1970s. 

Nathan Hack died at 87, October 4, 1971 in Santa Monica, California. He came from Poland at the age of 16 and founded in Detroit the "Hack Shoe Company" in 1916. He later became president of The Greater Detroit Shoe Retailers Association and honorary life president of the Michigan Shoe Association. The photograph here below portrays Hack in 1966.

1966 | Nathan Hack and his Ripple Soles
Source: Detroit Free Press


To rephrase Nathan Hack quote: the ripple sole will relieve the strain of dozen shoe designers looking for something old to be copied. And that happened straight away.

1967/1968 TITANO
Cerro Maggiore, Milan

1971 | V.I.P. (Verolanuova Industria Plastica)
Thermoplastic injection
Verolanuova, Brescia

"After much testing Adidas has come up with THE ripple sole: soft, durable, extremely comfortable and functional." 
After much testing, THEIR ripple sole was used for the models ANTELOPE and ROM.

1988 | Patrick Cox
Source: Shoes by Colin McDowell

2010 | George Cox for Japan's BAL

Clockwise from top left:
2012 Buttero; 2013/2014 Ash; 2012 Hiroshi Tsubouchi; 2015 Paciotti