pulley/ rack combo

Tony you may want to try this shorter configuration, Just remove the bottom link, and two connecting side plates, and move the 5/8" roller to where the 7/16" roller now resides, This will leave you with 2 5/8" rollers on the same side as the hitch climber pulley.
It does not take as much friction this way below the hitch, as there is less roller chain length, but when releasing the hitch on a doubled rope it allows the hitch to bear a little more weigh rather than practically nothing at all. On a single line you have to work a little more to release the hitch but that is not nessecarily a bad thing.

Gordon
002-2.jpg
 
Jamin mentioned he would like to see an all steel hitch, and so..... I made one
102_1522.jpg

The top OAR arm causes the rope to take a very slight bend when on line , but slack, and so grips the rope when weighted, adding friction above the collapsing rack portion of the pulley/rack. It tends like a dream and has less sit back than the hitch dependent model.
 
I think it might could be. If you could send me say a ten or 15 foot piece of the rope you climb with, I could try to make a custom rack for you.

I have altered the hitchless rack pictured, and have the top link inserted through the hole pictured in the rigid link headstock. By extending the headstock out an inch further, it gives a short handle that can be squeezed to release, sort of like a unicender in that regard, but one that tends slack. and is self advancing on a doubled line, just like the unicender and my OAR.

I have also used the pulley/rack in a RADS system on a doubled line, by advancing the hand ascender with revolver, above the P/R each stroke. Talk about mechanical advantage... I can pull myself upwards hand over fist with ease, and when I stop pulling, the rack engages and holds my progress. I am not sure but it seems like a 5:1 block and tackle.
 
I have tried the pulley rack on a hardware 5/8 inch rope today and it does work fine. I think it could be tuned for a 5/8 arborist style rope.
 
I made another improvement today. I have incorporated a 10-40 thumb set screw into the headstock, so that I can fine tune the tension on various dia. ropes. This also allows me, if so desired, to limit the amount that it will release. I hope to make a video at some point.

Gordon
 
I was sitting around thinking about this all metal hitch and heat dissipation today. Have you done any high climbs with this and a rapid descent? I know other pieces get hot quick and with this being all metal was just wondering?
 
I did several ascents and descents (4 or 5) one after another up and down on about 15' of rope today and it was slightly warm to the touch. It does have 8 points of contact, 5 pins and 3 rollers, and the rollers were where rack was warm to the touch. I think it will handle the heat quite well.
 
Here is a video I made today with the help of my film-maker, showing how the hitchless pulley rack performs on ascent and descent. The video camera cut off the last part, but you can see most of the demo. At the end I demonstrate how I release the descent lever using my thumb. This device tends slack very well and pulls up the climbing line with little friction due to the rollers and hitch climber pulley installed.
http://www.youtube.com/watch?v=o0fiQvaQ6Pk
 
set screw makes me nervous. To close to the movement of your fingers. Have you thought of that? Or addressed it?

This is my first post on your work, but I have enjoyed watching the progression of your product. Keep tweaking it till its perfect I guess. Admirable, and brave of you for putting it to the jury

regards
 
the set screw has a very fine thread (10-40) and does not seem to be an issue.
In fact, when the hitch is weighted it does not affect the function of the pulley rack at all.
 
Very very cool. I like it a lot! Innovation is the the best thing to bring to life and thanks to yours, something beautiful has been born. I want one. Just for piece of mind i think a simple solution to pass standards would be an added connection thats officially rated for climbing from the biner to hitch.
 
Thanks. I had this idea for some time, but could not get it to engage the rope, until I realized that a headstock similar to my Bulldog OAR could be used. I did not realize it at the time, but Petzl was working on their own mechanical prussik at the same time I was, and have come out with the Zig-Zag. It is my understanding that the Zig-Zag will not work alone for SRT however. I no longer make the Pulley/Rack, but if you like I could put you in touch with an individual who has one.

Picture of early attempt at mechanical prussik
SAM_0596.jpg
 
Thanks Jamin, Here are some pictures from this past summer. I do not even have a pulley/rack in my possession, as I have moved on to concentrating on the Bulldog OAR.

First picture is with headstock installed:
002-4.jpg


second picture is with the hitch dependent rack:
003-3.jpg
 
I have a demo hitchless pulley/rack again which works SRT on ropes of 11.7 mm to 12.4 mm +-. This will work without the RW above. I am of course curious as to how it compares with the ZZ. If anyone is interested in trying it out and then returning it to me, I am willing to send it out, if you send 25.00 to cover shipping. (or visa-versa)!

Thanks, Gordon
 
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