making a vibratory compactor

I have a spare 13 horse Honda engine laying around and a need for a vibrato
ry compactor. My thought was to use the engine to drive a shaft attached to
two pillow block bearings. The shaft would have a piece of square tubing o
r something else welded to it to create the "off balance" effect.
Yes I know I can rent one but I need it for several different things and no
t all at the same time if that makes sense.
Any ideas on the proper way to build the out of balance shaft? Such as how
much weight and how far from the centerline of the axle it should be?
Thanks,
Reply to
stryped
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I have a spare 13 horse Honda engine laying around and a need for a vibratory compactor. My thought was to use the engine to drive a shaft attached to two pillow block bearings. The shaft would have a piece of square tubing or something else welded to it to create the "off balance" effect.
Yes I know I can rent one but I need it for several different things and not all at the same time if that makes sense.
Any ideas on the proper way to build the out of balance shaft? Such as how much weight and how far from the centerline of the axle it should be?
Thanks,
============
You could rent one the first time and study its design.
Reply to
Jim Wilkins
I have a spare 13 horse Honda engine laying around and a need for a vibratory compactor. My thought was to use the engine to drive a shaft attached to two pillow block bearings. The shaft would have a piece of square tubing or something else welded to it to create the "off balance" effect.
Yes I know I can rent one but I need it for several different things and not all at the same time if that makes sense.
Any ideas on the proper way to build the out of balance shaft? Such as how much weight and how far from the centerline of the axle it should be?
Thanks,
============
You could rent one the first time and study its design.
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HarborFreight has a 6.5 hp model,
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they say 5500 beats per minute and a total weight of 176 lbs. In the manual is an exploded diagram that is probably close to scale, which makes it look like they step up the engine speed less than 2:1 with pulleys and two drive belts in parallel, and the eccentric is pretty small. They list the bearings for the shaft as a 6308 so that tells you the shaft size and what strength bearings they felt it needed, the weight looks to be less than the shaft diameter and tight to one side of the shaft. They claim 3000 lbs of force. Anyway, just one place to get some info.
----- Regards, Carl Ijames
Reply to
Carl Ijames
Thanks so much. What size would you say those pulleys are?
Reply to
stryped
Thanks so much. What size would you say those pulleys are? ====================================================================
No comment :-). If I had to guess, I would print out that page and grab some calipers to get the ratio. Look up the 6308 bearing and use the eccentric shaft diameter to get the scale factor, then you could estimate the pulley diameters. If the motor runs at 3600 rpm which seems the popular speed for governed lawn mowers and such, and they get 5500 beats per minute, the step up ratio has to be 5500/3600=1.53 or just 1.5, and then just find some pulleys to get that ratio. Read the rest of the manual to see if they specify the engine speed, in case my 3600 guess is wrong. It's on sale for $550, and you could probably sell it for over half that when you are finally finished ... (Just saying; I know, building is the fun part for most here. For me it's doing the design work, I think through lots more designs than I ever try to build.)
----- Regards, Carl Ijames
Reply to
Carl Ijames
Looks like a 6308 bearing is about a 1.5 inch shaft. I would have never guess it to being that big....
Reply to
stryped
Looks like a 6308 bearing is about a 1.5 inch shaft. I would have never guess it to being that big.... ======================================================================================
They claim 3000 lb impact force, and they do want it to survive a few impacts. At 5500 per minute, say 1000 hours to wear out (complete guess on my part), that's 330 million impacts. Also a great reason not to couple the eccentric directly to the motor crankshaft :-). If you are going to step up a little, with 16.5 vs 6.5 hp, I'd keep the speed the same and guess the volume and center of gravity radius on the eccentric, then multiply the radius times the volume of theirs by 16.5/6.5 to get yours. Yes, you should convert volume to weight, but then you would just divide it right back out :-). I'd bump the shaft cross sectional area by 16.5/6.5 as well, and use a 6300 series bearing as well. You are going to need some very good vibration isolation mounts for that motor, too.
----- Regards, Carl Ijames
Reply to
Carl Ijames
Might also be a good plan t use two shafts rotating in opposite directions timed to produce vertical impact.
Reply to
geraldrmiller
Usually the plate and eccentric are one item. That is then isolated from the motor and drive assembly by isolation mounts. The one I have uses almost the same idea as a sway bar end link. Two rubber mounts on each end with a tube and bolt holding it together. Mounted at about a 45 degree angle.
Reply to
Steve W.
I actually thought of using two shafts but have never seen one with two so I was not sure how well it would work or how hard it would be to get the two shafts identical in terms of placement and weight.
Reply to
stryped
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Yea. I found some rubber mounts that are sold for MSD ignitions for racecar s. ABout 14 bucks for 4 of them. They are designed to reduce vibration to t he electronic ignition box.
Can any of you tell me how thick typically the plate is? I have some scrap 1/8 inch laying around, but I don't think any are big enough for a bottom p late. I may have to buy a sheet of it. (I think it is expensive. I may have some square tubing laying around I could use instead to form a flat bottom , but not sure how it would work compared to sheet steel.
One other question, on that diagram there are a series of discs on the engi ne shaft. I assume that is some sort of clutch? I wonder what I could use f or a clutch?
Reply to
stryped
If it's HF, the bearings are probably too small for the task and the motor.
This 6308 is a standard bearing, 40x90x23mm:
.
There are probably many many patents on how to build vibratory compactors. A few hours reading patents, especially the part where they talk about the problems they are solving, can be very useful.
Joe Gwinn
Reply to
Joe Gwinn
Mine has a 3/8" thick plate.
Most are a simple centrifugal clutch. Belt drive.
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Reply to
Steve W.

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