calculating distances

J

joe

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Where would be the best point to use on a limb or log to determine the paths of motion of the limb or log when they are being removed?

Joe
 
The best point Joe is determined by you. It depends on the circumstance and what you want the limb to do. It also depends on the shape of the limb and how the weight is distributed. You can but tie it or tip tie it. You can tie it somewhere in the middle and try to balance it. You can even use a spider leg and balance it off. You can determine what will work best. Good luck.
 
I look for diffrent choices for hitching for balance, ballast and leveraging on the hinge and into the rig.

One of the reasons i like using slings is to be able to slide-adjust to fine tune this positioning for diffrent effects. Having a tightline to remove play from machine, helps make it more predict-able. I also like the self tourquing configurations. thaere are amny choices for each situation, which one is maximum?

i lean away from butt hitching as much as possible; i like the ballast, lever, and free length above the hitch; with softer, more forgiving end down.

-KC
 
BigJon and Mr.Spyder: where the rope is tied, or how I attach a work line to the limb, definitely influences the path of motion of the limb. If I'm looking at the limb, at what point on the limb itself would I pick to describe the motion of the limb?

This is a discussion group. Anybody can add their observations to the questions.

Joe
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Joe to be totally honest I am not understanding the question. I always looked at the whole limb. Another thing I look at is grain of the wood. Limbs with old stress fractures or things of that nature have an effect on your notch. It is like barganing. You give the branch a little bit of what it wants and little of what you want it to do. With right notch and good lowering line placement you can get a limb to do just about anything you want provided the man running the rope understands the mechanics of what is happening. I would suggest taking a course with arbor master or getting the videos. Rip Tompkins is a great guy and has alot of valuable information to offer.
 
i try to describe the placement of the hitchpoint on the load; by the work i am trying to get it to perform. Of course that will take balance and leverage info of that work. also if you are trying to get it to twist or tourque, so just more that n linear placement / explanation might be necessary.

-KC
 
Joe have you ever seen the movie Patch Adams? When you look at the limb, how many limbs do you see? Hmmm.... I am not really sure where you are trying to lead this discussion. I really do think you are over analyzing the whole process. Here is a new technique for you try, it is called cut and hope. It always works for me pretty well. Take charge of the limb an make it do what you want.
 
<BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><HR>Originally posted by BigJon:
Joe have you ever seen the movie Patch Adams?<HR></BLOCKQUOTE>

Yes, I have seen Patch Adams, but, the part I remember most vividly was how the entrance for the gynecologists' convention was decorated.

<BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><HR>]Here is a new technique for you try, it is called cut and hope. It always works for me pretty well. Take charge of the limb an make it do what you want.<HR></BLOCKQUOTE>


I've done this a few times. I won't part with the method altogether. It's been too helpful. Aaaaahhhh, the
familiarity of guesswork.

Joe

[ September 21, 2002: Message edited by: joe ]
 
i try to attain a feeling that guides me, and second guesses; but before this goes any further; like i tell my guys: "No Hail Mary cuts here!" Besides, i learn so much examining before, predicting, and then examining after; to feed info in next time.

Though you probably wouldn't have guessed that!
 
I'm catching this topic a little late but let me just say that if we are talking about rope placment on a given limb I agree with John in many aspects.You must determin what you want to accomplish first and identify obstacles in the path and then formulate a plan.Getting yourself in the best position to see things clearly and instruct your ground crew exactly what you invision taking place.I dont agree witn "cut and hope " ,if I understand you correctly,I think you can sometimes get into trouble that way(although I admit to doing it myself).I agree with John firmly that you can make any situation work for you with some good planning.
Joe if you are looking to go in a differnt direction with this topic such as looking at the limb and judgeing the exact point of balance based on all the vectors involved,I wouldnt know where to begin .but it would be interesting.
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Out of curiousity, has any1 read the umn.edu web site I posted earlier in this thread? Did the info make enough sense that it could be applied in the field?

Joe

[ September 20, 2002: Message edited by: joe ]
 
Joe, yes I read through it, and they are talking about mostly, center of mass and finding that point and how it reacts.

THis does apply to tree work, but you must understand, that we are not always looking for the center of mass, unless we are trying to rig something out level.Setting up a spider leg system with two slings is one way to find close to center. Another is setting up a single line tied at two points on the limb on either side of what you think the center may be. Put a prussik on it and adjust your apex to center.Then attach the bulline to it with a biner.(Use this system considering your load rates) These are just two ways to find your center of mass. .However, when rigging long cants out in a even load and single line, you do have the chance of a twirling effect. JUst like the web page mentions.Because now we have found the center of mass.
So, yes this does apply to some of our work when we are rigging. Especially when we want to move a limb over a object without the tip or butt dropping. Or if we want to lower it to the ground flat.
There can be many facters involved when riggin limbs and finding the center of mass this just one of the many facters that we use for certain cases.
I hope I didnt go off the deep end here and your question was somewhat answered.

Thanks,
Greg
 
<BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><HR>Originally posted by klimbinfool:
Joe, yes I read through it, and they are talking about mostly, center of mass and finding that point and how it reacts.

This does apply to tree work, but you must understand, that we are not always looking for the center of mass, unless we are trying to rig something out level.<HR></BLOCKQUOTE>

Hi, Greg;

When I rig, I always guess where I think the center of mass of the limb being rigged is located.
http://www.uark.edu/depts/aeedhp/agscience/simpmach.htm

This page further explains why we need to know where the center of mass/gravity is located when rigging limbs. (This 2nd page is the same concept as the umn.edu site.) Essentially, when a line is attached to a limb, we create a lever. As long as the limb is attached to the tree, the limb attachment is a fulcrum.
Gravity influences weight and is the force to be overcome. The work line is
the resistence. This means where the line is located in relation to the limbs' center of mass/gravity will determine the type of lever created.
This will also determine the potential
tension in the work line and the force at the rigging point.

<BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><HR>Setting up a spider leg system with two slings is one way to find close to center. Another is setting up a single line tied at two points on the limb on either side of what you think the center may be.<HR></BLOCKQUOTE>

If the center of mass/gravity is always in mind when rigging, it should be discovered which line in a 2 line system holds more weight.

<BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><HR>Put a prussik on it and adjust your apex to center.Then attach the bulline to it with a biner.(Use this system considering your load rates) These are just two ways to find your center of mass.<HR></BLOCKQUOTE>

Using a single line near the limbs center of mass/gravity along with a butt hitch should help one to learn where a limbs center of mass/gravity is located. When a limb swings, it's center of mass/gravity will swing underneath the rigging point along with the potential to rotate, thus, the need for a butt line.

<BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><HR>However, when rigging long cants out in a even load and single line, you do have the chance of a twirling effect.<HR></BLOCKQUOTE>

The twirling effect is angular momentum. Once a limb is cut free from the tree, the work line becomes the fulcrum and a 1st class lever is created.

<BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><HR>There can be many facters involved when riggin limbs and finding the center of mass this just one of the many facters that we use for certain cases.<HR></BLOCKQUOTE>

It is my opinion 1 should learn where the limbs center of mass/gravity is located in all cases. It should be realized pretty much everthing we do when rigging revolves around the center of mass/gravity of the systems for which we use and work.

<BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><HR>I hope I didn't go off the deep end here<HR></BLOCKQUOTE>

Nope.

<BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><HR>and your question was somewhat answered.

Thanks,
Greg<HR></BLOCKQUOTE>

My question is being answered. Thanks for an honest reply.

Joe
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p.s. treeclimber165: we posted about the same time which is why our posts are out of sync.

[ September 21, 2002: Message edited by: joe ]
 
When I first started climbing, I did a lot of 'cut-n-hope' because I had no experience to draw from. I've learned how different types of cuts react differently and how to 'see' the center of weight in a limb.
I've never been a big fan of trying to balance a limb when rigging, too easy to get in trouble. If balancing is called for, I usually try to make the brushy end heavier so as to keep the butt end up and away from potential targets. Brush will not do as much damage as a chunk of wood when swinging into an obstacle.
Most of the time taking a smaller piece will reduce or eliminate some risk, but many times taking a larger piece will be safer. All depends on the situation at hand and your understanding of what that limb will do after you cut it. Like Spydey says, you need to make the weight and mass of the limb work FOR you rather than against you.
I don't know how to describe it better, but I certainly understand it. Using the tree and it's characteristics to work for you, rather than trying to overpower each piece or limb. (I hope this applies to this conversation, otherwise I have no idea what you are asking or talking about.)
 
I look at the center of mass, on which side of the hitch that it is, and at how close that the center of mass is to said hitch point to determine leverage.

i firmly beleive that at full line stretch per load, that this hitchpoint becomes the pivot; before full stretch of the line is reached, the hinge is the pivot. When the hinge is the pivot, that is a class 2 lever( center of mass opposite hinge from hitchpoint); when the hitchpoint is the pivot, that is class 1 (IMAO); 2 totally diffrent machines to pro-gram.

i try to keep the center of balance out from between these 2 possible pivots. If you can enter leverage class 1 status before tearoff of the hinge, the length of the spar between the hinge and the hitch becomes a lever for the hinge to control the head through, after tearoff this length becomes a ballast to the sinking head; the length of this ballast rides 'free' as far as ground clearance is concerned, as it rides above the hitch.

i think that before tearoff the sweep of the hinge is dictated by the mechanical instruction of the 'openness' of the face(and leveraged and torquing position of hitch and it's supportand steering); while the directional axis is as like dictated by the axis of the hinge flap, the side to side pulls (or pushes on travel) are adjusted for by the balance of holding wood across the face of the hinge. The length of the load (from hinge to tip) dictating the reach; that makes the hinge dictate the 3 dimensions in space!

i try to look at rigging as gravity powered machinery, i try to keep this machinery's motion posititve and predictable by using a tight rigging line,then let the slow hinging pretighten the line to max support/steering before tearoff. At max support/stretch per load is where the leverage machinery changes classes, and diffrent things become possible.

Center of balance is very important in felling, rigging, topping etc. The relationship between the center of balance and hitch determines if you (hitch point) have leverage on the mass or the reverse, and to what extent. The same hitchpoint and hinge points leverage characteristics can be changed by changes in this center of balance; whereby a tree putting on leaves, nuts above the hitchpoint, or you removing limbs below the hitchpoint can all 3 change the center of balance higher/farther out, thereby decreasing the amount of leverage that the hitchpoint has on the load; without changing the hitchpoint or knotch position.

Taking all this to ballet things out, then adding the self torquing/tightening w/~1.3/1 leverageing on hitchpoint makes beautiful; machinery in my eyes!

Well, i guess that .02 is spent!

Very nice, simple explanation in link Joe, i tend ot think of 3 machines Lever (inclusive of greater leverage of wheel over axle/bearing), Pulley (which is same as wheel axle until rope is run), and Inclined Plane (inclusive of wedge and screw); but all distilled down further to "The Law of Energy Conservation". Which all at once defines all these things. For any given energy source/power; you can take a machine and draw more power or speed from that source, but not both, as they must reciprocate each other, being the only 2 factors that still must equal the same energy source's input. Every convergence of energy has a cost to that energy's total; so there is no perpetual motion, there are more efficient machines, but none 100% or balls would bounce forever, 1 single bullet could kill 1000's that where inline with it. No energy or effort dissipates, it all just changes form and can be accounted for. Even fossil fuels where grown from energy, changed, crushed under tons of force for millions of years; even this energy doesn't just come from no where........ it is all accountable, seeing that opens many doors.

[ October 30, 2002: Message edited by: TheTreeSpyder ]
 
O Mr. Joe,

Without a formal education; i must admit that those strange symbols just look like Greek to me!!
shocked.gif
But as all ways, still quite a good link!

i kinda was thinking that if it was leaving after tearoff there wouldn't really be any torque? Especially, in a balanced load, where there would be no spin, therefore no torque?

But, probably staying more in co-operation with what i think your meaning, the 'door' hinging before tearoff at the flap of hinge would be a description of the length pivoting on the hinge through it's sweep who's speed is controlled by the leverage on the line. i kinda think that in your examples that in lowering the torque would be higher generally, being as the input force would be at the end (gravity pulling down at farthest point from hinge and support line). In plotting the path; i would say that it is simply the load's length and dimension during it's sweep on the hinge, then same on it's supported hitch, then lowering point to ground.

But in the lifting scenario, the torque would be lower as the line is the input force. Dictating that the hitchpoint would be at the balance point, would cause that it probably would not be in a measured center in most tree work; thereby not at a 50% torque position, but in between the 2 (end and center, for med. high torque)?

In other words the 2 examples would be diffrent for the line is the power on lifting, while gravity pulling at a diffrent position is the input force in lowering.

Also in lowering the pretightening of the line, and it's amount of immediate braking force to the movement would be in consideration. For it remains my contention that in common lowering, once the line achieves full support on the load (tightenned to leveraged weight of load) the machine of motion changes from pivoting on the hinge (2nd class lever) to pivoting on the hitch (1st class lever). The diffrence being sometimes phenomenal to me if i can achieve the latter before tearoff (after tearoff the latter must be achieved?). For in the former, typical (2nd class), the mass of leverage is the input force pivoting on the hinge, line controlled. While, the latter, more elusive (1st class before tearoff), the mass is still the input, but the hitch is the pivot and the hinge the controller.

In the rigging that i still try to think of names for that wee have tossed back and forth privately and publically, i tend not to recognize this hinging as torquing because of this; when i have spoke of self torquing rig, i am speaking of a spinning force wanting to turn top to bottom along the axis of the load; then taking that force and trapping it (with rib of hinge before tearoff, and possibly branch or karab after) to effect a turn from this trapped, torqued force. This in turn lets the line more efficiently grant support, as any part of the total force of the load that is turning is not pulling down, thereby tending to stay higher during that part of the sweep, from this reduction of downward pull, scheduling that to work for me while clearing the obstacle below.

Well, i guess that most would agree that the meter says my 2cents has run out!
 
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