14 July 2009

New dual axle cam from DMM

DMM recently announced a new double axle cam - dubbed the 'Dragon'. They are clearly inspired by the BD Camalots, however they are meant to be lighter and also have extender slings. Since the patent on the double axle design expired in 2005, DMM are the first company to make use of the design.

Image from DMM

There has been some confusion in the past on when the double axle patent expired. The patent is US 4,643,377 titled 'Mechanically expanding climbing aid'. A US patent lasts 20 years from the filing or priority date (whichever is earlier) or 17 years from the date the patent was granted - so long as the patent in question was in force in 1995, the longer of these two options applies. US 4,643,377 was filed in 1985 and granted in 1987 - therefore the 20 year term from 1985 is the lifetime that applies, meaning the patent expired in 2005.

The relevent US Code is here: http://www.law.cornell.edu/uscode/35/154(c).html