Sitting in Luton airport on the day of 9/11, Fred Hall (technical director and chairman at DMM) and Chris Rowlands (exports manager) were stranded on their way out to Switzerland for a business trip. As everything was at a standstill, Fred and Chris brainstormed ideas for new gear. On their return to Wales, they asked the team at DMM a simple question: what is the heaviest piece of gear on your harness?
The size 8 cam or a set of large nuts, you might say? No, the heaviest piece of gear on is your rope. The longer the pitch the more work is involved in dragging it up behind you.
With this issue and other objectives in mind, DMM set about trying to come up with a solution for minimising rope drag. DMM focused their attention on the performance of quickdraw carabiners commonly used in traditional climbing.
To tackle this issue, the team looked at designing a new carabiner with an integrated pulley wheel. A few days later with the rudimentary steel prototypes in hand, a group headed to the old Beacon Climbing Centre to carry out some rudimentary tests; two hauling systems were set up—one with the standard carabiners and another with the new prototypes—with the rope zig-zagging through the carabiners.
Following subsequent prototypes and further testing at the DMM factory in Llanberis, the team found they could achieve up to a 30% reduction in friction and rope drag. The integrated pulley wheel in what became the Revolver allowed ropes to run more efficiently through the carabiner by converting energy into movement. Replacing sliding friction with the moving friction of a bearing.
The Revolver was the first ever carabiner with a pulley wheel, a key element for reducing rope drag on wandering or lengthy climbing pitches. Initially intended for traditional climbing, the versatility of the pulley wheel proved useful for mountain guides wanting lightweight hauling systems and crevasse rescue kits.