let alone hold + lift + rip hinge...
How common is common sense
- Thread starter murphy4trees
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Tom Dunlap
Addicted to ArboristSite
Referring to the lower pic on p. 44.
It seems to me that some MA is gained because of the lever arm? I think this is ground that's been treaded before.
I prefer to use a soft connection when I use piggy back MA instead of cams. From what I've gathered, when hitches slip the power curve is rounded rather than spikey when a cam slips and grabs.
Tom
It seems to me that some MA is gained because of the lever arm? I think this is ground that's been treaded before.
I prefer to use a soft connection when I use piggy back MA instead of cams. From what I've gathered, when hitches slip the power curve is rounded rather than spikey when a cam slips and grabs.
Tom
murphy4trees
Addicted to ArboristSite
Good point Tom...
My bad... pic is clean cause some of the limbs weight is still supported by the holding wood...
My bad... pic is clean cause some of the limbs weight is still supported by the holding wood...
At 12o'clock high from the pivot of the hinge; there would be the weight of the load; irrespective of the length, the load would be the weight, without leveraging; becuase of not being in leveraged position.
The 1000# is at a leveraged position, and has leveraged length. The leveraged load at 2'oclock is ~86% x C.o.B.Length(leverage) x weight (?). So here, might be 1000# x .86 x length/2; so might be ~5000#?. Whether more support was given by the hinge, than was required to flex hinge as you lift, might be dependant on strength:flexability ratio of wood and thickness of hinge etc.?
The way that it is rigged, any more lift must shear load from hinge; for it can no longer arc on hinge leveraged, for hitch point is straight under support point; yet it doens't look like the faces have met..... (not good?)
The MA of the arm, would be lift force x hitch position from hinge (leverage arm distance) to force tearoff as the faces met. Otherwise the length is leverage of load weight against hinge, not for?
i think that at hold and lower, the hinge helps more; but at lifting, the lift must fight the leveraged force of the load, and fight the hinge to make it bend too. The helpful part i think is that the lift starts at a high leverage position (3O'Clock) so is a strong lift, but then this lift has decreasing amount of load on it (moving up close to vertical). ad stood up to olower leveraged position on the hinge. Generally i look for weaker hinges from these lifts i think....
If the hitch laced over the top to the backside of the load; the most shearing leverage to force tearoff would be had, also the most allowable and powerfull arc-ing distance on the hinge; 2 seperate factors i think.
i think that if the overhead support point is back closer to the hinge; this induces molre arc-ed motion on hinge; less swing at tearoff, more likely to arc and leverage the faces together to force tearoff with that, rathger than with saw or straight up lift, also during the most leveraged loads of arc, the line is pulling back into the hinge; giving it's support at a more helpful angle/direction when needed most automatically; IMLHO.
Or something like that
:alien:
The 1000# is at a leveraged position, and has leveraged length. The leveraged load at 2'oclock is ~86% x C.o.B.Length(leverage) x weight (?). So here, might be 1000# x .86 x length/2; so might be ~5000#?. Whether more support was given by the hinge, than was required to flex hinge as you lift, might be dependant on strength:flexability ratio of wood and thickness of hinge etc.?
The way that it is rigged, any more lift must shear load from hinge; for it can no longer arc on hinge leveraged, for hitch point is straight under support point; yet it doens't look like the faces have met..... (not good?)
The MA of the arm, would be lift force x hitch position from hinge (leverage arm distance) to force tearoff as the faces met. Otherwise the length is leverage of load weight against hinge, not for?
i think that at hold and lower, the hinge helps more; but at lifting, the lift must fight the leveraged force of the load, and fight the hinge to make it bend too. The helpful part i think is that the lift starts at a high leverage position (3O'Clock) so is a strong lift, but then this lift has decreasing amount of load on it (moving up close to vertical). ad stood up to olower leveraged position on the hinge. Generally i look for weaker hinges from these lifts i think....
If the hitch laced over the top to the backside of the load; the most shearing leverage to force tearoff would be had, also the most allowable and powerfull arc-ing distance on the hinge; 2 seperate factors i think.
i think that if the overhead support point is back closer to the hinge; this induces molre arc-ed motion on hinge; less swing at tearoff, more likely to arc and leverage the faces together to force tearoff with that, rathger than with saw or straight up lift, also during the most leveraged loads of arc, the line is pulling back into the hinge; giving it's support at a more helpful angle/direction when needed most automatically; IMLHO.
Or something like that
:alien:
