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Post by bradblazer on Aug 30, 2009 23:56:53 GMT -5
I'm pretty slack about checking my Yahoo mail so I find a 2-week old message from Larry Gugliotta offering to cut me out the parts for a grapple.  ;D When I finally responded he was all over it - sent me some drawing files and asked if there was anything I wanted to do to make them cool and custom.  My Koyker 195 bucket turns out to be quite a bit bigger in profile than Larry's so he made the grapple longer and started working out the geometry. Larry's pretty much a whiz in working that out in AutoCad but I felt kinda bad him doing all of that work while I'm sitting with Autodesk Inventor full 3-D CAD on my laptop. I sketched it up in Inventor and figured out I need about 120 degrees of swing to make it work. I made up an Excel spreadsheet and was able to solve the dimensions and angles to get the required motion, then tweak it based on predicted speed and tip force to give the desired performance. I'm using a 2x8" cylinder with a range of motion from 20.25 to 28.25 inches. It puts out around 700lb at full pressure. I graphed the ratio of grapple tip speed to cylinder speed as well as force at the tips over the range of motion. I adjusted the pin spacing so it moves fast/loses power as it approaches the fully up stops which provides more power at the opposite end of the range as the grapple closes. (yellow is force, aqua is speed ratio and blue is angle)  |
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Post by bradblazer on Aug 31, 2009 0:08:05 GMT -5
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FlyHiFlyLo
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2007 Jinma 554LE
Posts: 425
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Post by FlyHiFlyLo on Aug 31, 2009 0:19:41 GMT -5
This weekend I finally finished the model.   It lets me check things like the predicted jaw position when fully closed and the clearance between the cylinder and the connection tube (which Larry noticed isn't much).   Nice Model... |
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Post by bradblazer on Aug 31, 2009 0:26:30 GMT -5
I'm still getting the hang of Inventor 2010 - just got the upgrade last week. I have to ask - how do my welds look?  So what cool, custom features does it have? Some pseudo-truss and curvy cutouts plus plenty of chain keyholes. In final form I got rid of the cutouts at the base end of the jaw profiles because I was concerned about resistance to any side loading.  Of course the whole thing is based on Larry's overall design and he had plenty of input throughout. What a great guy. It sure pays to belong to this forum. Hmmm, I wonder what it will look like in action? The motion in the video is totally driven by the length of the cylinder. You can see the extra speed approaching fully up.  Here's a smoother video using a 10 second cycle.  |
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Turbo
CTW Member
Posts: 49
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Post by Turbo on Aug 31, 2009 7:52:38 GMT -5
Impressive to say the least! You guy's come up with some nice modes on this site. That inventor 2010 is neat, I been using Google sketch-up for my designs, but it doesn't have video  Nice work. |
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Post by bradblazer on Aug 31, 2009 8:44:07 GMT -5
Thanks guys.
Sketchup = free, Inventor 2010 = $6,000.00. (I'm working with a shared license though) It better have some bells and whistles! The best part is that it seems much more stable than the 2008 version.
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quikduk
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Dog House
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Post by quikduk on Aug 31, 2009 14:52:02 GMT -5
Very cool Brad. I like the addition of the chain slots. Do you think they would put undue stress on the grapple causing it to buckle? I could use some chain locks like that in the center of my bucket. As it is now, I use the two hooks I welded onto the top.
Larry,
OAN, have you had any luck on the text curving DXF thing? My home desktop has some issues ATM. I am still looking for a converter that doesn't strip the block.
Ken
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Post by Rich Waugh on Aug 31, 2009 15:31:45 GMT -5
Man, that is some really nice work! Now I simply HAVE to have one. My only real obstacle is that I don't know how to do all that slick design work and don't have access to a plasma cutter and I'm cheap as shit, too. Other than that, I'm ready to go! (grin)
I do think I might be able to cobble one together with just my band saws, welders and other stuff, it just won't look so bitchin' cool. Probably still grab brush and tree limbs, though, and that's what I really need. I'll just have to do it with the little pieces of cardboard taped together instead of that slick CAD modeling.
I'm really looking forward to seeing the finished product. Hell, if you get the price down to a hundred bucks, I'll buy one! (grin)
Outstanding work!
Rich
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Post by bradblazer on Aug 31, 2009 20:22:28 GMT -5
Ken,
To me the chain slots are pretty experimental in terms of what I will use them for. Not anything too extreme in terms of heavy lifting. I know it would be risky to use tractive force pulling on a chain attached to a raised grapple.
Right now I wrap the chains around my extra long bucket teeth and it works pretty good.
Rich,
Thanks - If you can provide dimensions I can do some designing for you. Most of the work is already done.
If you can't get plasma cut parts there are plenty of other good options for grapple construction. I had actually been toying with the idea of using my pipe bender to make jaws out of pipe with welded on teeth.
No matter how they are made, grapples are pretty cool by definition.
Brad
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Post by Rich Waugh on Aug 31, 2009 21:57:04 GMT -5
That's a really generous offer Brad, and I may take you up on it later on. I can make the grapple arms easily enough - I was thinking about forging a pair from some leaf spring stock I have. Should make them very strong but lighter weight. The rest of it is pretty straightforward fabrication work except for the plumbing. The whole project will have to wait until I get the new FEL valve installed so I have the power beyond capability. I'll get it all done, it just may take a while.
Thanks again for the offer!
Rich
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GuglioLS
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Jinma354 LE
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Post by GuglioLS on Aug 31, 2009 23:32:28 GMT -5
.......SNIP.......SNIP........ I have to ask - how do my welds look? For once I must say those welds do look a "little" better than mine, I suppose  MAN Brad that thing is totally awesome! Best virtual grapple I ever saw. Thanks for your generous compliments. Brad is all too kind and humble. In reality he is responsible for all the trick design work. A big mention of credit goes to Rob for inspiring me to install a grapple on my tractor along with all his original design work which was later plasma cut, and installed on Kens and Loretta's tractors. When I started attempting to draw basic parts for Brad's bucket, I soon realized how much I was really in over my head and how much effort was put into my grapple design by Rob. I'm sure glad Brad took the bull by the horns completing the design in record time. Now I have a true appreciation of how much skill and knowledge it takes to design one of these. Kudos to Brad for his design and 3D with animation! Not to mention an Excel spread sheet plotting out geometry, speed and force - who would of though that possible? Now it's up to me to plasma cut the parts and make this become reality for Brad. Wish me luck. I like the idea Rich has for a "poor mans grapple" You won't have to worry if you dent or scratch it ;D Brads alternate idea of bent tube with weld on teeth also sound like a winner for a custom grapple. In my mind the chain keyholes are like Brad said "experimental" with their primary function being lite-in-ing holes (to make the parts lighter) not a lightning rod  After all, WTF do you need chain for when you can just grab whatever with the grapple jaws -right? FWIW my idea was to have several perfect 72* five point stars for lightening holes, it would have had the military look and "feel" But since this is going on Brads tractor, I caved on that idea. I look forward to cutting out the parts soon. I got to find some boxes for shipping these bad boys. the jaws are close to 32" long, A rough calculation (very rough) tells me the jaws will weigh in at around 10# each. Larry PS Ken- No I have not figured out why text from A-cad will not import into the PlasmaCam software. That's why I sent the software to you so you would figure it out for me, remember  |
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Post by bradblazer on Sept 1, 2009 10:47:05 GMT -5
MAN Brad that thing is totally awesome! Best virtual grapple I ever saw. Thanks Larry - I might have to have one of my steamfitter brothers weld it up for me or it will never look like that! A rough calculation (very rough) tells me the jaws will weigh in at around 10# each. Pretty good. Here are the mass numbers from Inventor. I don't know what "relative error" means, probably resolution of the model. Jaw: 9.396 lbmass (Relative Error = 0.000150%) Jaw connecting plate: 9.195 lbmass (Relative Error = 0.001397%) Cylinder protector plate: 8.727 lbmass (Relative Error = 0.000153%) Jaw cylinder bracket: 2.545 lbmass (Relative Error = 0.000189%) Cylinder base bracket: 2.442 lbmass (Relative Error = 0.000116%) Arm base bracket: 0.863 lbmass (Relative Error = 0.000426%) Grapple jaw weldment: 66.587 lbmass (Relative Error = 0.001982%) |
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Post by bradblazer on Sept 1, 2009 11:18:35 GMT -5
Larry, I have an emboss function that should work to convert text to something in a dxf you can cut out.  |
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GuglioLS
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Post by GuglioLS on Sept 1, 2009 22:29:03 GMT -5
Larry, I have an emboss function that should work to convert text to something in a dxf you can cut out. Thanks Brad, Is that emboss function a feature of inventor? Does it do arc text? Arc text is really what I was wanting for making signs. Trouble is no text of any kind generated in A-cad will import into the plasma software. The arc under the text converts but not the text I really need something on the spot handy. I think Corel Draw may be the ticket for that? I believe another handy feature in corel is free hand draw and convert that to a DXF file. There is no free hand drawing in A-cad or the plasma software which make artwork nearly impossible. Larry |
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quikduk
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Post by quikduk on Sept 1, 2009 22:43:44 GMT -5
Larry, No I haven't forgotten. The PC with my software is on the fritz so I am typing this on one of the Mac laptops we have. I like the idea of Corel Draw...and I may have a copy to install and try it...but I have drawn freehand arcs etc from splines that were then converted to polylines (Plines) and then DXF'ed. They kept their shape so I will pose the question to some of my AUGI (AutoCAD Users Group International) friends and see what they come up with. I also have a friend with AutoCAD Civil 3D and it may have a text as contour tool. I'll have to investigate further. IMHO we need to have the curved text convert to a spline or pline group...but how? ?  Brad, it looks great! I can't wait to see it working. My 3rrl/GuglioLS/Mrs3rrl grapple is still going strong. I should be getting some tractor time in this weekend too. ;D ;D ;D ;D ;D...finally... |
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;D When I finally responded he was all over it - sent me some drawing files and asked if there was anything I wanted to do to make them cool and custom. 
After all, WTF do you need chain for when you can just grab whatever with the grapple jaws -right? FWIW my idea was to have several perfect 72* five point stars for lightening holes, it would have had the military look and "feel" But since this is going on Brads tractor, I caved on that idea.
