Five actors from Happy Days are suing CBS for $40 million over profits from merchandise related to the hit 1970s US television series, according to court documents.

The show, which followed the exploits of Fonzie (Henry Winkler) and Richie (Ron Howard), went off the air more than 26 years ago but still generates income through clothing, DVDs and slot machines, according to the complaint.

The lawsuit was filed at the Supreme Court of Los Angeles by lawyers representing Anson Williams, Don Most, Marion Ross, Erin Moran and the estate of Tom Bosley (who died last October).

Neither Mr Winkler nor Mr Howard, who went on to become an Academy Award-winning director, were named in the suit.

The cast of Happy Days became “iconic characters of timeless Americana,” the complaint says.

“Families all across America would gather around the television and be captivated by the Cunninghams and their friends’ adventures during the 1950s.”

The show has had “a lasting effect on Americans as well as American television and is still an integral part of pop culture even today.”

A spokesman for CBS said on Tuesday it had tried, without success, to reach an amicable agreement with the five former cast members.

The show, set in the 1950s and 1960s, ran from 1974 to 1984 and was produced by Garry Marshall, who went on to direct Julia Roberts in the hit 1990 film Pretty Woman.