According to this thread. As far as I know, the design has been used for more than 200 yo. They were used as utility knife in garden, farm and jungle. Some of them are slightly modified to suit local wood (rattan, bamboo, coconut, hardwood, softwood etc.)
Here 's the antique type.
http://www.vikingsword.com/vb/showthread.php?t=2798
And you may find more modern type here.
http://images.google.co.th/images?hl...-8&sa=N&tab=wi