Pistol Grip Wrist Saving Arborist Tool

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  • #252
If your trying to improve grip, would a D shaped handle not be the first port of call. Straight wrist with no forward pressure

Yeah Pete, a D shaped handle has advantages and will be integrated into prototype two or three, depending on how well this one functions aloft.

Ideally I'd like to be able to attach and tighten the cord to the branch with just my left hand in just a few seconds, without any electronics whatsoever. Quite doable of course, but right now just attaching to the branch with my left hand alone'll have to suffice.

There's a lot of merit in keeping it simple, durable and relatively inexpensive, as in under 500 bucks a pop.

There are cordless 1/4 inch drive ratchets with enough power to tighten up on the branch at the touch of a button, but that'll have to wait for prototype #4.

Jomo
 
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  • #253
Now this pic's just for the Bermster!

The rest of yuz don't look!

Jomo
 

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I still think you can do away with cutting the line and having to retie the ring at every branch.
I would use a steel cable with a cam type tensioner (havens?Chicago grip scaled down) and a nubbin on the other end with a bow and arrow type quick release. F
Flip it around, lock release, snug up, cut, and pull trigger.
 
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  • #255
Actually I'm going to make a custom ring with a graduated funnel n slot so a single knot'll slide right into it Flush.

My very first grip pliers prototype used a steel cable, and the backlash from it after releasing a heavy load was very painful.

Synthetic cord's much more user friendly IME.

Jomo
 
K. I. S. S.

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  • #257
It's important to bear in mind that this tool's not meant to be used on every branch you intend to cut n chuck, just the awkward heavy hard to hold branches that take alotta gripping strength.

Jomo
 
My very first grip pliers prototype used a steel cable, and the backlash from it after releasing a heavy load was very painful
The steel cable doesn't help, but the main actor of the backlash is the grip plier itself. You get the same when you clamp seriously some steel stock for welding or folding. With a rotating cam (for example), that shouldn't be a concern.

Just an idea, make a conical end or a nosecone at the limb's contact. That will reduce the lever arm on the device and facilitate the limb's movements with less parasite force on the handle.
 
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  • #260
Point taken Marc, and prototype ARP !!'s gonna need one, but just being round's sufficient at the contact point.

It's cuttin that cord beyond doubt that was given me fits!

I'm still a bit astonished by how much spring power, and how big a sliding hammer inside the barrel it took to do it.

The sliding hammer slams into the lower stainless steel arm of pet claw clipper pliers, forcing closure and cutting the cord quite dependably in the blink of an eye. Cutting cords under high tensile loads is easy, but under no load's the gold standard.

Doing all this dirt cheap's the real challenge.

But this spring bolt cutter hammer trigger combo's just that, all the components under 25 bucks!

All today's tests, 50 lbs, 5lbs n no lbs, all cut away cleanly.

It'll be another week or two before true field testing aloft's done, but the hard part's over.

Prototype II can most assuredly cut it, with an easy pull of the trigger.

Jomo
 

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  • #263
Actually Jim, that's a rubberized AK47 rifle grip, made in Israel.

This one'll weigh a tad over 3 lbs, not bad considering there's abouta lb of sliding hammer steel n spring inside the barrel.

Allota finishing touches yet, but I'm happy bout how well it cuts, and should ideally never need sharpening.

Jomo
 

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  • #265
So I'm thinkin you've got a light trigger, you're catchin moderately heavy loads, one handed with this contraption.

Inadvertent trigger activation's inevitable without taking preventative measures, Murphy screams out!

That forefinger needs a weight bearing ring, just the right distance away from the trigger, bout half an inch.

Rangs n Sprangs n agrivatin thangs!

Jomo
 
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  • #268
One thing's for sure, prototyping's a huge PITA!

So I went out yesterday, bought a few random brands of cord, confident my pistol'd cut em all, huge spring, slide hammer, no sweat!

Only to hurry home n test em, and suffer agonizin, humiliatin defeat. These polyester jacketed nylon cords are tough!

Now I'm a bit miffed, unbelieving that such a huge compression spring, powering that heavy a hammer, can only cut halfway through a high quality cord.

It's gotta be the limited inch and a quarter throw of the hammer slide. Since there's gotta be no doubt whatsoever about cuttin cleanly every friggin time, an overwhelming force?

A couple heavy duty tension springs, to add even more power to the huge compression spring in the barrel's, a must.

That much resistance makes cocking the pistol a somewhat Herculean task though. Solved by attaching a tiny pulley to the slide hammer body, and gaining a 2:1 mechanical advantage pulling my starter/cocking cord out the back of the pistol, a bit like a chainsaw.

If this doubling of power doesn't cut any dang cord I load this Pistol with, I'm a gonna quit this biz n join the stinkin Clanton Gang!
 

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  • #269
Since lightweight's so desirable from a climber's perspective, it's inevitable that all this heavy steel gets exnayed, supplanted by either electric hotwire cutting tech, insulated in plastic, or pneumatic airgun tech CO2 cartridge.

Prototypes four, five n six.

Keepin it simple n keepin it light seems pert near impossible!

Jomo
 
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  • #271
Yeah well, I'm drillin n filin like a dog, gettin blisters!
 

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  • #273
More like muscle bound heavy weight champion cord cuttin pistoleros?

Weighin in at a whopping four n a quarter pounds, senor ARP the third!

I thin ez too heavy......
 

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...Small battery pack w leads to a heating element at the cord cutting blade ... Nice instant clean melt cut. Just keep it red hot.
 
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  • #275
Yeah I watched a dude on YouTube slap together a homemade hotwire foam cutter usin one C battery.

The trick's keepin it insulated, and how fast that wire heats up once energized?

If it heats up super quick, say in the course of the trigger's travel throw, half an inch?

Bingo! Baterries should last all day!

But I'm a gonna get el jefe the third here workin like a charm, if'n it's the last thing I do....

Jomo
 
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