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


Anonymous said...

Will be interesting to see if lightness and sling length are the only differences DMM implement in their Dragon cams.

Surely after all these years they will have thought of some way to make them more ~ robust, bigger range, less likely to creep,...

Virgil said...

Apparently the cam angle will be 13.75 on the Dragons, whilst the Camalots use 14.5 - so the dragons are likely to have a very slightly smaller range, in exchange for more 'holding power'. It appears in reality the difference not really significant:

Dragon ranges: http://www.ukclimbing.com/news/item.php?id=48937


Camalot ranges: http://www.alpineexposures.com/pages/black-diamond-c4-camalot-review