Need help with tree trimming invention

[quarky]

Greetings, fellow tinkerers, engineers, inventors.

Having recent tree limb problems around my house, and finding the cost of a bucket truck prohibitive, I started fooling around with an electric chainsaw on a pole, with a remote on and off switch. This works up to a point, but holding the pole out eventually becomes impossible.

It did occur to me that a telescoping boom of some sort would greatly add to the utility of the device, and be small enough to attach to a pick-up truck, or be set on a small trailer that could be moved into position.

For my own needs, this is too much effort...but it does seem worth the effort as a rent-able tool for others that can't handle the big bucket trucks.
A fair amount of googling showed almost nothing on the matter.

One of my concerns before going further is the potential for the chain to get bound up, as often happens in logging. The cure is a second chainsaw...meaning that 2 of the new devices would be required on a job.

Now I'm wondering about cutting limbs with high-pressure water.
The wand would be much lighter than what would be needed to support a chainsaw at, say, 60 feet from the base. The flow of water through the hose might also be somewhat self-supporting. No binding would occur, but would a 2500psi pressure washer rig cut a big tree limb? I've cut small pieces of wood with one, accidently, oops, on a job.

Feedback appreciated, especially if anyone knows what I'm getting at.

[Earthborn]

Having recent tree limb problems around my house, and finding the cost of a bucket truck prohibitive, I started fooling around with an electric chainsaw on a pole, with a remote on and off switch.Sounds somewhat... dangerous.

It did occur to me that a telescoping boom of some sort would greatly add to the utility of the device, and be small enough to attach to a pick-up truck, or be set on a small trailer that could be moved into position.If I understand you correctly, you propose a vehicle with an arm that ends in a saw... I'm pretty sure such things already exist, in fact there are things that are better.

Here (http://www.techfresh.net/wp-content/uploads/2008/05/logging-spider.jpg) is one that has an arm that grabs a tree, saws it through, and gently puts it down. And oh, yeah... It also treads lightly to not damage the terrain.

[Jungle Jim]

Here (http://www.techfresh.net/wp-content/uploads/2008/05/logging-spider.jpg) is one that has an arm that grabs a tree, saws it through, and gently puts it down. And oh, yeah... It also treads lightly to not damage the terrain.

Now that's one cool machine.

[quarky]

yes, that's cool. I'm after something simpler; cheaper.

[!Kaggen]

Greetings, fellow tinkerers, engineers, inventors.

Having recent tree limb problems around my house, and finding the cost of a bucket truck prohibitive, I started fooling around with an electric chainsaw on a pole, with a remote on and off switch. This works up to a point, but holding the pole out eventually becomes impossible.

It did occur to me that a telescoping boom of some sort would greatly add to the utility of the device, and be small enough to attach to a pick-up truck, or be set on a small trailer that could be moved into position.

For my own needs, this is too much effort...but it does seem worth the effort as a rent-able tool for others that can't handle the big bucket trucks.
A fair amount of googling showed almost nothing on the matter.

One of my concerns before going further is the potential for the chain to get bound up, as often happens in logging. The cure is a second chainsaw...meaning that 2 of the new devices would be required on a job.

Now I'm wondering about cutting limbs with high-pressure water.
The wand would be much lighter than what would be needed to support a chainsaw at, say, 60 feet from the base. The flow of water through the hose might also be somewhat self-supporting. No binding would occur, but would a 2500psi pressure washer rig cut a big tree limb? I've cut small pieces of wood with one, accidently, oops, on a job.

Feedback appreciated, especially if anyone knows what I'm getting at.

Is this not long enough?
http://www.stihl.co.za/pole-pruners-and-hedge-trimmers/77/100-ht-75.html

[jasonpatterson]

Is this not long enough?
http://www.stihl.co.za/pole-pruners-and-hedge-trimmers/77/100-ht-75.html

I've got an unpowered pole saw that is about 5m extended, plus 2 more for myself, and it's not nearly long enough to do much of what I need to do. I wind up on ladders, or climbing the tree, or going up on my roof more often than not.

In any case, the way to find out whether your idea would work or not is to keep your eyes peeled for someone trimming trees and snag a few thick chunks of freshly cut wood. Try it out. Be sure to try both hard and soft woods, and if it can't cut through both fairly rapidly, say a 6" oak branch in one minute or two at most, it's not going to be a viable idea. (I know I'd be P.O.ed if I rented a limb cutter that took forever to get the job done...)

I wouldn't be surprised if the thing was able to cut through thinner branches very rapidly, but as the branch grows thicker, not only is there going to be more wood to cut through, the source of the water will be farther and farther from the thickest part of the wood. Unless you can figure out a way to keep the water very tightly focused over a fairly good range of distances, that might be another issue you run into.

[quarky]

Is this not long enough?
http://www.stihl.co.za/pole-pruners-and-hedge-trimmers/77/100-ht-75.html

No; not long enough. These are big trees, 100' tall and more. Some of the places are too tight for the bucket truck to access, even if I could afford it.
If said device could be assembled, it would be very useful where storms have happened.

[ben m]

Hi Quarky,

A few thoughts. That *does* sound like a good idea---and not just for mounting on a boom for treetops. I'm willing to bet that a water jet cutter could be made much safer than a handheld chainsaw for any sort of tree work.

So, water jet cutting---with 30,000 psi water/abrasive slurries that saw through metal---is avery mature technology which you should look into. But the Wikipedia article says something interesting: http://en.wikipedia.org/wiki/Water_jet_cutter

In the 1950s, forestry engineer Dr. Norman Franz experimented with an early form of water jet cutter to cut lumber. However, the technology did not advance notably until the 1970s when Dr. Mohamed Hashish created a technique to add abrasives to the water jet cutter.

So that's something to look into. One more thing: I haven't run the numbers but I strongly doubt that the water flow will support much of the weight of your boom. (And it's not like you will always aim the jet straight downwards, anyway.)

[Delvo]

No; not long enough. These are big trees, 100' tall and more.How high up on them do you want to cut branches from?

[Delvo]

One of my concerns before going further is the potential for the chain to get bound up, as often happens in logging. The cure is a second chainsaw...meaning that 2 of the new devices would be required on a job.What about solid blades? Those machines are always less likely to break, and easier to fix when broken, than chainsaws. Chainsaws only exist despite their mechanical issues because a solid circular blade's shape sometimes won't fit where you want it and the back-and-forth movement of solid straight blades makes them hard to handle. Solve either of those problems for straight blades, and you don't need to deal with chains.

For a circular-blade system, if you're only cutting branches off of trunks, the space/size issue could be handled by matching blade size to branch size. A machine with easily detachable blades of different sizes (and appropriate motor adjustments for the different resistance and torque) would then be applicable for branches of various sizes. For a straight-blade system, a motor similar to those in ordinary jig saws but bigger could do the work, and the machine could brace itself against the shaking from the direction-reversals by clamping on to the branch it's cutting or neighboring branches, or wrapping around the trunk.

For that matter, a claw or pair of opposing gripping arms or such would be a good idea for any cutting mechanism you use. Then the operator doesn't need to hold the machine up there, handling both the weight and any kickback forces it produces in whatever directions they'd push in. The operator just sticks it up to the target branch, closes the clamps, and can practically let go except for holding the trigger.

[quarky]

Good thoughts. Thanks, guys.

I'd thought of a sawzall-type cutter, instead of a chain. If the blade got hung up, it could be released from the tool, and a new blade put in.
A big pair of clippers also occurred to me. Has potential.

The water jet might possibly be the lightest rig, allowing a longer boom arm with less materials.

The "cherry-picker" bucket trucks, which is what I'd want to compete with, can reach 75 feet...but the trucks are huge; expensive; not many available in one locale; too heavy for soft, wet ground...and they put the person in the bucket in some danger.

The boom required to support a 10-20 lb tool (with remote controls) would certainly be a lot lighter than what is needed to hold a human out there.

Another snag in my idea is the loss of control as per lowering the cut branch after it is cut free.

I've also pondered air tools for this use, as the hose length can be quite long.
Thanks again. Any more thoughts on it are greatly appreciated.

[Beanbag]

My suggestion would be to use a set of pneumatic or hydraulic shears for branches up to about 4" (100mm) in diameter. First off, it's quieter. Second off, the load on the boom will be less because the power source (the pump) will remain on the ground. Mechanically, the "head" will be simpler than a chainsaw, with fewer moving parts, and those that do move will be running at a much slower speed.

A chainsaw's advantage is that the cutting force is continuously applied in one direction, and that it is fairly rigid in construction. A reciprocating saw reverses direction constantly, and when located at the end of a long boom, the amount of force needed to stabilize the blade against the work will be tremendous because the boom acts as a lever, of which you the operator are on the small end. A possible solution (at the cost of an increase in complexity) would be to have two thin reciprocating blades mounted side-by-side, working 180 degrees in opposition, to where when one is going forward, the other is going backward -- think electric carving knife.

Somebody manufactures lopping shears with a ratchet-action handle where you "pump" the handle several times, each closing stroke reduced through gearing to increase the cutting force at the cost of slowing the advance of the cutting blade. You might consider a worm-drive mechanism to close the cutting jaws.

Just a few ideas. I like the cutting jaws because when the branch gives away, the cutting head will probably sway back and forth wildly, and the jaws would be safer than a still-spinning chainsaw head. Think power lines and such.

Beanbag

[bruto]

I like the water jet idea, but I don't thihk a standard high pressure washer will do it well. From my experience, although it might cut through a branch it will shred and splinter the wood, which would be bad for the tree. A water jet might work, but remember that high pressure will have a lot of thrust, and this will be magnified by the length of the pole. I'm guessing that it will be hard to control. Even a regular pressure washer handle requires a pretty firm grip.

The sawzall idea, I think also would be a no-go because reciprocating blades will tend to bend when they bind, so you'll be ruining a lot of them even if they don't end up stuck up in the tree. Pruning saws usually are curved so that they can cut over the top, but I suspect that a mechanical reciprocating saw would jump around with curved blades.

Of course there are already little chainsaw pruners made, so you don't have to reinvent that. I've never tried one but they look as if they ought to work well.

I have some of those ratcheting lopping shears. They are quite powerful, and if you could adapt something like that you might get much better results than you do with a plain pole pruner. You still will have a limit to the amount the jaws can open. But then, there's likely a limit to how large a limb you should prune freehand before getting it rigged.

I think linemen and other pros already have hydraulic loppers, but of course the problem here is powering them in an economical way. They also are already up in buckets, so they don't need ultra-long handles. I think you're always going to reach a practical limit of handle height for any device that can do useful work.