Any body built a knuckleboom loader

[muddstopper]

I have thought about that, but I just aint sure. The bearings are located in each end of the hub (inner/outer). The wheel flange is in the middle of the hub. The springs that the housing bolts to is toward the center of the housing, outside the range of the bearings. I am thinking the housing spindle would feel the same effect of side load whether it is on a truck or on the boom. I dont know any other way to figure it, and I certainly dont know if I'm figuring it correctly. I wish someone with experience with this sort of thing could add their :2cents:

Just to add, I havent measured the bearing spacing, but the distance between the inner and outer bearing on a large truck axle is pretty large, guessing 12inches or more. I can overbuild this by adding a solid shaft thru the middle of the spindle and adding another bearing at the bottom of the shaft if necessary, but that shaft would still depend on the outer bearing of the hub for top support. I dont think I would gain anything by doing so.

 

[mikehaugen]

I have thought about that, but I just aint sure. The bearings are located in each end of the hub (inner/outer). The wheel flange is in the middle of the hub. The springs that the housing bolts to is toward the center of the housing, outside the range of the bearings. I am thinking the housing spindle would feel the same effect of side load whether it is on a truck or on the boom. I dont know any other way to figure it, and I certainly dont know if I'm figuring it correctly. I wish someone with experience with this sort of thing could add their :2cents:

Just to add, I havent measured the bearing spacing, but the distance between the inner and outer bearing on a large truck axle is pretty large, guessing 12inches or more. I can overbuild this by adding a solid shaft thru the middle of the spindle and adding another bearing at the bottom of the shaft if necessary, but that shaft would still depend on the outer bearing of the hub for top support. I dont think I would gain anything by doing so.

I'm no engineer, but the way I figure it, a 40,000lb hub mean each bearing 20,000. If you stick a big arm hanging out, the force(torque) will be applied to both bearings, each bearing individually will see that load instead of both sharing the load.

I imagine a tee bolted to a wall- if the bolts are 6" above and below the part sticking out and you have a 5' arm hanging out with 100lbs at the end, the top bolt will have 500lbs of force pulling out, and the bottom will have 500lbs pushing into the wall. If you hung it from the ceiling instead, they would share whatever load was on it.

I would figure half of the 40,000lbs as a capacity(20,000 for each bearing). So if you have say a 20' boom, and the bearings are 12" apart that is a 20:1 leverage ratio. I would say it could hold 1000 lbs. Now obviously we know they can hold more than their rating, and they may be adequate... I just don't know.

 

[mikehaugen]

If you built a tower and put the entire axle (shortened of course) next to the tower and put a plate on both top and bottom hubs with your pivoting mast next to axle it would utilize both hubs and be of a push/pull force on the hubs and would at least double the capacity. You could probably get at least 270 degrees of swing out of it.

Sorry it probably isn't clear, if I was at my computer I would draw a picture.

 

[muddstopper]

A pic would clear it up, but I think I understand.

My 40,000 lb rearend is rated at 20,000lbs per side. I plan on using just one side. The bearings should be able to hold 20,000lbs, 10.000lbs per bearing, but the spindle at the axle tube needs to hold 20,000lbs also. The bearing should transfer the load to the spindle. Its the spindle i am concerned with breaking off. The way I am looking at it is the wheels on the hub should transfer all weight to the spindle and the spindle transfers the load to the springs, which are located away from the hub and bearing. I will get a measurement to see just how far. If the axle tube is secured at the same point as where the spring was bolted, then it should hold up 20,000lbs. Now I dont know if this is correct, but I am thinking that the top bearing should support 10,000lbs of side force of the boom pulling, The bottom bearing should support 10,000lbs of the boom pushing and the total is still 20,000lbs and that weight is what is transfered to the spindle. Probably doesnt work that way, but that is what I am thinking.

The only way I can think to stiffen it up would be to use the axle shaft bolted to the hub as it normally is, and add a bearing to the other end of the shaft, but I dont really think that will help and only add extra weight. The alterative would be to install a bushing inside the top of the spindle tube to fit a large shaft and then add another bushing or bearing at the opposite end of the axle tube to support the shaft. That would certainly stiffen the spindle and take some load off the bearings. I havent went an got the axle housing yet, so I cant do any kind of measurement to see just how big the id of the spindle tube is. A big truck axle hub is about 8 1/2in OD and pretty thick, 3/4 wall?? maybe more. Spindle tube probably around 6in??? just guesses.

 

[mikehaugen]

My 40,000 lb rearend is rated at 20,000lbs per side.

Yes, I was thinking incorrectly. For some reason I was thinking 40k per side. All I can say is to try it. Trying to come up with exact numbers, to me it will come up short. But as I said it may be just fine because of the de-rating. Also they are designed to hold the load at 70 mph and see a lot of shock loads.

 

[CDN Farm Boy]

As I read along with this, something just isn't sitting right to me...that something is missing in the calculations. I figured out what it is this morning.

You say you are looking to pick up 3000 lbs at the end of the 16' boom. My math tells me that will equate to 48,000 lbs of leverage at the pivot. Never mind the specific design of the pivot, I don't think you'll have enough counter weight in your 7000 lbs trailer to do it. Yes, outriggers will shorten the lever length but have you checked on this part of the math?

 

[bigdeano]

If I were building this, I would look into the idea in post #43. Stand the whole rear axle up on end and use both wheel flanges to mount your crane to. Probably a 1 or 2 ton axle would be strong enough to carry the torque imposed on it. Then you could use the 4:1 gear reduction with a hyd motor to pivot the crane. You wouldn't need a big expensive sprocket.

 

[bcp]

Some ideas:

Home Made Trailer and Crane

Build your own professional Forestry-Trailer!

Bruce

 

[jimmysisson]

Here's an example of a unit for sale near me: 2008 Metavic Forwarding Trailer (might have to copy-paste)
The post does not look as rugged as you're talking about re the truck axle. Might be going back to pipe-in-pipe plus a thrust bearing could be simpler?
Jim

 

[mikehaugen]

A pic would clear it up, but I think I understand.

I spent hours on this computer simulation so I hope it helps. The Yellow would be some sort of post, the black is the truck axle, and the red would be the pivoting mast. Like I said, it won't get you 360 degrees, but hopefully close to 270 or so.

 

[muddstopper]

As I read along with this, something just isn't sitting right to me...that something is missing in the calculations. I figured out what it is this morning.

You say you are looking to pick up 3000 lbs at the end of the 16' boom. My math tells me that will equate to 48,000 lbs of leverage at the pivot. Never mind the specific design of the pivot, I don't think you'll have enough counter weight in your 7000 lbs trailer to do it. Yes, outriggers will shorten the lever length but have you checked on this part of the math?

You are almost correct. The 3000lb number was with boom retracted, not at full extention. With dipper boom at a 90# angle to the root boom, loads would be aboth half of what they would be with both boom fully extended. I dont antisipate ever haveing a 3000lb log hanging from the end of a fully extened boom. I can see a possibility of reaching and dragging a 3000lb log close to the trailer before picking it up I also intend to use outriggers at all four corners to support the trailer. The 7000lb weight number is the estimated weight of the loader and the firewood processor and doesnot include the eintire weight of the trailer. Trailer is 8ft wide and close to the ground, I havent figured out a lenght for the outriggers, but if measured from the center of the loader to the outermost point of each outrigger, i would have to guess the outriggers would be 16ft wide tip to tip. I havent actually drew anything up to take measurements from. I do see your point of overbalanceing the center mast and think this is certainly something that needs to be considered. I do think the math would be the same as figureing leveage force of a lever, with the outrigger being the balanceing point and the boom being the lever. With a fulcrum of 8f from the center of the mast, with a levr of 16ft, it should be a 2:1 weight ratio. If extended lenght of boom is 16ft, and oputriggers are at 8ft from mast, the opposite 4ft of the trailer width would be my counter weight. If trailer weight is 7000lb, than counterweight potential would be 3500lbs. Since the boom would be mounted on the end of the trailer, I would probably have to reduce the counter balnce by anothe 50%. Of course these numbers are just off the top of my head and probably wont reflect the actual trailer weight or counter balance effect. This is something i have thought about, but just havent figured out if my method of calculations are correct. Any ideals as to whether I am on the right track will be appreciated.

 

[mikefromnh]

If it starts to tip just lower the boom

 

[Yooper75]

Muddstopper, I don't know if you've ever run a boom like you're trying to build but they are a different animal and I've been running them for going on 14 years. I think you're 3000# retracted is overly optimistic since the biggest loader we have can do 3000# at 42ft of stick fully extended and about 4,700 retracted mounted on a truck that weighs just under 36,000# empty with the loader. The biggest Wallentein logging trailer with boom will do 1200# at 11ft of reach full stick which is half the reach of our biggest IMT retracted the biggest thing you're going to have to worry about is getting something very heavy at the end of the stick and the hydraulics being stronger than the material ripping the boom apart trying to overcome the weight of the boom/load. Our IMT and Prentice loaders have pressure relieves built in so they don't rip themselves apart and will actually stop working if you reach the working limits of the loader with the only function is to lower/knuckle in the boom until you get back to safe operating limits. There is nothing more nerve wracking than having a 3,600 pound unit of OSB hanging off the stick over someones new floor and the loader says nope you're done when you reach the load limits or the truck/loader start to go over if an outrigger lets go or the ground collapses under it with you sitting 13ft in the air with no where to go.

 

[Baby Grand]

Most excitement I can remember was with the Prentice, trying to put a 30 sheet unit of 12' 1/2" sheetrock through the second story window opening in a just sheathed house. Boom was fully extended at right angles to the truck. Stabilizer started to settle into the ground causing the whole shebang to tip in the load direction. Hydraulics barely recovered the load because even at a slight tip angle it didn't have enough mustard to spin the load. Only by bringing the load back, closer to the mast could I keep the boom turning the right way and the vehicle from going over into the excavation around the foundation. Sitting on top of the mast just adds to the excitement!

 

[Yooper75]

My favorite was trying to stick a unit of 5/8-4x16 sheetrock through a window with a 20mph North wind trying to rotate either the entire loader or the forks every time I eased off on the hydraulics for those two functions. The next I was running our new IMT 42ft boom nosed up to the house with the stick fully extended 48+ feet in the air to unload a pallet of shingles on a 3 story home and the roofer decides to stick his feet in the pallet and tosses 80# bundles to the guys on the roof while swinging is the breeze with no life line.

Good times!!:laughing:

 

[muddstopper]

You havent ran a loader until you run one with rail wheels. Then have it derail in the direction of a passing train. Yea, I can come up with some scary stories too. Non the less, I do understand the limitations and have several years of experience running one. Just not lately. Once ran a tower crain dropping materials down a shaft . Bottom of tower was 90ft in the air, Seems like the boom was 90ft long with a jib attached to the end. Bossman told me I needed to grease the roller at the end of the jib. Handed me a flashlight, (I was working night shift), and a grease gun. He expected me to crawl thru the framework to get to the jib. I turned in my 5 days notice then and there. Far as I know, that roller has never been greased.

My intentions are to run this boom from the ground. I am not a big fan of heights, just in case my last story didnt give that fact away. Anyways, I can concur with the statement about having more lift capacity than the boom can handle. I dont think that will be the case here, but is something that needs to be well thought out before buying the steel for the boom. Glad for the reminder because even though I know this could happen, I havent been thinking about it.

I have looked at the Wallentien loaders, and the Anderson, and the Farmi and just about every other brand out there. I think that 1200lb rating is with the boom fully extended at 11ft. One of the manufacturers, I dont remember which one, uses a 4in solid shaft as the swivel support, another uses a 3in solid shaft. Both use 2 1/2 in bore cylinders. I plan on the 3in cylinders and a bigger spindle support. Also those small knuckle booms are mounted on narrow trailers. My trailer will be 8ft wide. They use one outrigger on each side (2), I plan on using one at each corner (4)That factor alone should give me more insurance from tipping. I havent planned on the lenght of the outriggers yet, but that is also another factor in lift capacity. Really my biggest concern is over powering the spindle and, now that it has been brought up, ripping off one of the booms. I think one can limit the lift capacity by using pressure reliefs in the hydraulics. I know there is probably some equasion that says you can only lift this much if you do this thing, but I dont know it and will probably have to use trial and error. In reality, I am planning on lifting firewood logs, if I run across a 3000lb log, it will probably be set aside and sold as a saw log. A 3000lb log is about a half a cord of firewood, maybe a little more once split and measured in cubic ft instead of weight.

 

[zzvyb6]

A few for sale in the area...

Knuckle boom crane "last one "

 

[mikefromnh]

hiab knuckleboom crane on Ford chassis

 

[muddstopper]

Why are so many small loaders for sale up north, and nothing but big loaders for sale in the south?

 

[breadtrk]

That is the stuff filtering out of Texas?