The water kingfishers or Cerylidae are one of the three families of bird in the kingfisher group, and are also known as the belted kingfishers or cerylid kingfishers.
... friction.
The device is covered by US patents 3,726,146 (1973) and 5,353,655 (1994) by L.A. Mishler and US patent 5,800,311 (1998) by P.S.Chuang.
Externa ...