Machine Design

Looking Back 6/09/2011

10 YEARS AGO — 2001
Kayak trades paddles for pedals: A penguin flapping its wings to generate forward thrust is the best analogy for the new Mirage Drive for kayaks from Hobie Cat Co., Oceanside, Calif., says Engineering Vice President Greg Ketterman.

Linking the kayak’s underwater fins to the foot pedals driving them is a support made of Verton RF from LNP Engineering Plastics, Exton, Pa. The support pivots on a stainless-steel shaft to which three cables attach. The cables apply force to a chain-and-sprocket arrangement which moves the fins back and forth.

Hobie Cat switched to the Verton RF product when an acetal bushing in the original aluminum casting wore out after a season or two of use. The all-composite design not only solves the wear problem but is also much stiffer than the casting. “This is important because excessive flex in the support promotes slack in the cables and, in extreme cases, can let chains skip a tooth on drive sprockets,” explains Ketterman. “Users say the Verton RF material gives the mechanism a good stiff feel.”

30 YEARS AGO — 1981
Rail road tests tires: An earthmover is shown crawling up a bed of rails in a tire test at the Goodyear proving ground near San Angelo, Tex. The unusual road provides a test for cut resistance of rubber compounds and is one of a myriad of evaluations given tires at the 7,300-acre facility.

50 YEARS AGO — 1961
Radio-size television, one of the “Sets of the Seventies” proposed by Radio Corp. of America, depends upon successful development of a very-thin picture tube. So far, RCA has made an experimental tube 2-in. deep for black and white, but picture quality is not good. All 1970 TV sets will receive color broadcasts, according to RCA. This little model would also have stereophonic radio and be clock operated.

© 2011 Penton Media, Inc.

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