A bit of history about my endeavor to create an ascender/descender. I first became aware of Morgan's Unicender early in 2010 and was fascinated by the concept, but wanted to make certain improvements as I heard of things that users wished would work better, such as wear issues, slack tending, smoother release, and secure attachment. I released my first public video march of 2010, showing what I called an OAR (Offset Ascending Rack) and it was not too much later that I hit upon the original idea of using two open ended arms, with an ANSI swivel link so that the rope could be captured securely mid-line (for which I have applied for a patent). I was at first using the top arm(s) to act as a brake for descent. It was after this that I met Kevin and he gave me a ZK-1, to which I added a sheave, and made an opened ended wrench with a swivel link I called a Dogbone. I would like to publicly thank Kevin for giving me a one time compensation for my sheave idea contribution to the ZK-2. I then had the idea to make my pulley/rack with a zig-zag rack (this was before the Petzl zigzag went public) They had come up with the same concept independent of my device and we were unaware of each others devices. I will say that as far as I know the one user who has my pulley/rack is still using it (SRT) and has no breakage issues with it. Around this time Jamie became interested in my OAR design and I sent him a demo to use and he liked it. He asked if he could modify it as long as he gave me attribution for the swivel link concept, and I agreed. Jamie sent me a demo of his first model and now he is on to his second, I can certainly relate to the time, effort, and expense that goes unseen in creating a device. subsequently I met Paul at the Charlotte competition where he was showing his Hitchhiker and later he generously gave me a HH, (Which I promptly modified for my own use by making it all mechanical, no hitch cord). Kevin came out with his rope runner which shares some attributes of the HH and his RW. I like to think that we have been inspired by each others inventions and that the arborist community has benefitted. I hope that my Bulldog Bone, which shares attributes of the Uni, HH, RW, and OAR can join this group.
Gordon Svedberg aka surveyor