Rigging pulley

klimbinfool

klimbinfool

Location
magalia california
I was roping out some large latterals on a American Elm last week at about seventy feet and in a fairly high traffic area.The ropping all went well and the ground crew was cleaning up as I pulled all my rigging out.I craddled my tower, and bent down to pull out my gear and found the rigging block had come apart and was laying in two pieces at the bottom of my bucket.My heart started to pound at the thought of what might have happend. The bolt had backed out and the sheeve was lying beside the cheek plates. Being that it was a emergency call out, I was in a hurry and didnt check the bolt as normal.This style pulley has a t bar welded on the bolt for tightening and can loosen when banging against the tree under loads.My fault tatally for not checking it.Just glad nothing got damadged or nobody got hurt.
 
What do you think about adding a tether to tie off the wing on the bolt? Look at aircraft assemblies and some racing applications, you'll wee that the fasteners are wired. If the bolt is long enough, you could drill a hole on the end and wire or pin it securely.

Tom
 
Thats a good Idea Tom, I'll have to look at this block a little closer to see if thats possible. I think I can at the top of the cheek plates. I'm not real fond of this style of block, but it's what I'm using.
thanks
Greg
 
This has happened to me twice with two different types of block. One was a Hobbs, the other was an ISC with the spring release captive bushing. The Hobbs hadn't unscrewed all the way, but I bet it would have been mangled. There was no need for this as the bolt has a keeper pin. I check this is tightened before climbing now.

The ISC turned against the stem whilst lowering and I observed the pin push in and twist as the block turned against the stem. Fortunately it didn't pop out, but I'm very careful how I position the block against the stem now.

I have also had a cow hitch come undone - I tied it as a girth hitch, and then tied a half hitch around the stem above the girth hitch rather than the sling leg holding the pulley. I had tied it like this before without a hint of a problem. It didn't want to work this time though! I think as the load came on the line it twisted the sling around the stem to loosen the girth hitch rather than tighten it. No one came close to injury as they were out of the drop zone and I was topping out, but it does make you think.

Needless to say, I now always tie two half hitches around the leg of the sling that holds the pulley!

I wouldn't recommend altering any pulley without the manufacturer's consent - you may find yourself uninsured in the event of an accident.
shocked.gif
 
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