View Full Version : Complicated dozer lift mechanisms
01-20-2008, 01:15 PM
It's been awhile since I posted here. Building a new house. It's done so I'd like to see if I can find an answer to a question I've been pondering for a long time.
Why in the world were so many older dozer blade lift mechanisms so complicated? Did someone have patent protection on a direct cylinder to blade connection like seen on most newer blades?
I've got RD4 with a Kay-Bruner blade with so many pins and bushings that are worn that it's hard to control. A little wear in each one makes for a lot of uncontrolled movement of the blade.
Just really curious.
01-20-2008, 01:30 PM
I've often wondered about that myself.....seems like they went to great extremes to build an odd ball contraption to do the job.
I guess most of it stems from the fact that these tractors were not originally designed or foreseen as dozers......plus the desire to be able to mount on both narrow and wide gage limited the options. None of them were close to getting it right until the hardnose hydraulic cylinder mounting systems came about.
01-20-2008, 02:38 PM
And yet it's not like it wasn't done. I've got this beautiful blade mount on my little 1941 Cletrac HG that has a very direct linkage. I don't know if the mount is of a different age, and it certainly looks custom built for this tractor, but it's very simple and strong as well as made to reinforce the frame at the attachment points. They made them, like mine with a hydraulic tilt or like another one I've got, with hydraulic angle. I think they could even be combined to have both for sort of 6 way blade. (Maybe a project when I have more time than sense.) It would have been mighty heavy on the front of the tractor but still pretty cool.
Photo of the Anderson blade with tilt mechanism: http://groups.msn.com/MikesRustyandShinyStuff/constsructionequipment.msnw?action=ShowPhoto&PhotoID=372
01-20-2008, 04:17 PM
Interesting, that's a nice HG. I have a couple of Cletracs, an AG and an AD. I started to fabricate a blade patterned after the Anderson set up but.....another project back burnered. Got any more pics of how that internal blade tilt mechanism works? Thanks
01-20-2008, 11:45 PM
Both based on the fact that hydraulics were very new at the time...
A) Since seal technology was in its infancy, maybe all the levers, pins and links isolated the rams from direct impact loads that could spike the pressures enough to blow out the piston or gland seals.
B) Like anything new and unproven, hydraulics were regarded with some skepticism by consumers, and building a system that looked more mechanical was a selling point.
01-21-2008, 05:45 AM
Hydraulic pressures used in the early days were very low, therefore the cylinders used were quite large. Direct acting cylinders would have been very bulky hanging on the front. Mechanical leverage was used since the cylinder push was less than modern hydraulics, as well.
Check out the LaPlant Choate blades used on the Cat 60 and 30 models from the 20's and 30's. The cylinder used on the back of the blade attachment was quite large.
01-21-2008, 06:39 AM
Mike, that is a beautiful paint job on the Cletrac. I've wondered if it would not have been a lot more efficient to put the cylindar at the front of the tractor to pull more or less directly upward on the blade instead of at an angle to the blade. I'm obviously no engineer, but it would seem that it would take less energy to pull up instead of at an angle. I think some modern Cats do pretty much that now days. GWH
01-21-2008, 03:05 PM
Thanks, gwh. That urethane does look like it's wet when new. I used ProLine paint which, here in San Diego, is what they use at the shipyards for tank lining and environments with high abrasive action on the paint. It's holding up as well as you could expect on a tractor that I actually use.
CLBos, I'm sure you're right about the angle of the cylinder, but it was probably done that way because less metal (money) was required to mount it close to the frame. As an aftermarket accessory on a farming tractor without the hard nose Old Magnet mentioned it was probably cheaper to do it that way. On most of the old blades I've seen, including the Kay Bruner on my RD4, the mechanical advantage was actually a DISadvantage, as in a little movement of the cylinder moved the blade a lot. And a little wear causes a lot of slop. The cylinders seemed to be large diameter in order to get a lot of force (probably with low hyd. pressure and the seal issues, per carlsharp). Also, on the Cletrac, the cylinders are small but more than powerful enough to lift the front of the tractor way up in the air. This also makes me suspicious that it was built after hyd. pressures went up. It won't lift the blade real high though because of that positioning... about 16-18" above the ground. Plenty high for what I do.
Old Magnet- I'll put some more photos on the website as soon as my satellite figures it wants to work: http://groups.msn.com/MikesRustyandShinyStuff/shoebox.msnw
Look on page two of the "Pictures" under the album "Construction Equipment"
Thanks for all the input! Maybe when it's all put together we've found a reason for all the Rube Goldberg madness.
01-21-2008, 03:08 PM
Crap, the link didn't show up for the photos. Maybe if you cut and paste this one:
01-21-2008, 04:57 PM
Lots of neat pictures there. Are you the owner, operator, maintainer of all that stuff:) :) My hats off to you if that's the case.
01-21-2008, 10:06 PM
Yep, I'm the guy who owns it and gets to do all the upkeep and maintenance. Right now most of my time is spent keeping as much of it as possible running and generally kept from getting any worse than it already is. I try to restore something once and awhile, but much will have to wait until retirement (not all that far off!). House building slowed things down for a year or more and there's more on that to do before I can get serious on the old stuff again.
I put some more detailed photos of the Anderson blade on the website: http://groups.msn.com/MikesRustyandShinyStuff/shoebox.msnw
A few people have been interested in the Anderson blade before. It's a nice design.....simple and strong.....just how I like it. No relation to me though. Ha!
01-21-2008, 10:48 PM
Thanks for the picture....that's the first time I've seen one open to where you could see the hydraulic tilt mechanism....really is a good design.
Is that a "48" Studebaker sedan? My folks had a "47" which I seem to recall had a slightly different grill. I'm sure you've heard the term "Steadybreaker"....it was one of them;) ;)
This is the blade that I would like to combine features on.
I am curious as to how the push arms attach underneath. Have you ever seen one of these? They have parallel springs and I can't tell if they took advantage of the spring mounts for the blade or if the arms go all the way back to the track truck pivot shaft.
01-22-2008, 02:36 PM
hi, i want to mount a blade on my fifteen, but without hydraulics, what is possible??
i have a alternator on it so i thought about a 12volt cable winch., has anyone better ideas?? hand operation is not a option i think.:D
01-22-2008, 05:58 PM
Just depends on if you want to go hydraulic with a 12V hydraulic power unit or cable with a 12V winch.
I think the resevoir on the usual hydraulic unit would be a little too small, but maybe not. After all, if you took some time filling the system, once you got it full, your resevoir would only have to hold the difference between the stroke volume on the front and back (around the rod) of the piston in the cylinders. So absolute minumum tank capacity equal to the volume of the cylinder rods. The units are available in double acting or single acting valving and can either use a separate lever operated valve or usually integral electric solenoid operated valves you would operate with a double throw, momentary contact toggle switch.
Then you would have to worry about cooling the oil:)
01-22-2008, 11:06 PM
Hey Old Magnet,
I put another lot of pictures on the website, I think on page 4 of "Construction Equipment. I think they show a little better how it's mounted. There is a weldment on each side that bolts to the frame, the front of the weldment has the attachment for the upper end of the cylinder and the lower rear has the mount for the push arms. Again, a neat little bolt on package!
The photo you sent shows how small the cylinders were on a larger machine. Clearly an advancement of seals and pumps, I'd say. Higher pressures surely were required to operate such small cylinders.
If you'd like, I can email larger format photos that you can blow up a little more. I took a million when I did the restoration. I'll take some photos tomorrow of the other blade with the hydraulic angle adjustment. I've only used the angle adjustment insert on the HG a few times, but found that it was awkward, at best. Unless the bite of the cut is totally level it will, of course, cut at different depths at the front and back of the blade. Even when trying to level or grade loose material it causes problems. The blade also can be removed by just pulling the two large pins at the front part of the blade mount.
Hope this helps.
02-11-2008, 08:28 PM
I posted some more photos of the angling Anderson blade on my website: http://groups.msn.com/MikesRustyandShinyStuff/shoebox.msnw I'll leave them in the new folder for awhile.
I hope this helps shed a little light on how they did the angling with hydraulics.
02-11-2008, 09:12 PM
Thanks for the photo's.....I believe I got it.
Fabricated the two pusher channels some time ago but never got to the tilt mechanism....another of those back burnered projects. Have both a D4 straight and angle blade dozers but something smaller would also be nice.
Looked over your utility project pics.....had pretty much the same drill with some 1200 ft runs. Like that SS tank:) Did you have to put sprinkler system in the house to???
02-11-2008, 10:49 PM
Yeah, it was as they say, an interesting time. They didn't require sprinklers on the approved plans and I thought they were there buried in documentation too confusing to understand. I had heard they were required on all new construction here in sunny So Cal. At any rate, I had them installed while everything was open. It turns out the local Rural Fire Protection District DOES require them. We put sprinklers on top of the roof too. They are just manually turned on. All would have been a nasty thing to have to put in after the place was finished.
The tank is galvanized, 10,000 gallons. Just new and SHINY! It is also required and most of it is dedicated to the RFPD. I don't remember the length of the runs. They could have been shorter but I wanted the tank as high as possible and out of site. I hate the look of those things.
I hope the photos do help when you get to your project. I know how that whole thing works..........rarely enough time to get it all done. Let me know if there's anything else that would help.
Just been reading this thread about early hydraulic systems and the complicated leverage arms. The low pressure was one problem but the low flow of hydraulic oil was the main problem. If the cylinders were mounted direct to the nose the blade speed would have been to slow because of the low flow rate of the early hydraulic pumps, with the linkage the blade speed was increased but the cylinder was also bigger to compensate for the loss of leverage that the linkage created. With todays high flow pumps the cylinder can travel greater distances at higher pressure and can be smaller and directly fitted to the blade. Hope this answers some of your question.
02-12-2008, 08:49 AM
Can't say as I agree with your interpretation.....at 25 gpm for the D2, 37gpm for the D4, 65gpm for the D6 and 100gpm for the D7/8, these were not low flow systems. It's the 1000 psi pressure that was the limitation along with some strange linkages that drives the cylinder sizing .
02-12-2008, 10:31 AM
There is a "Catch 22" going on there. I'm not as familiar as Old Magnet is with all the stats, so just have to guess on this. Now THAT can get me in trouble quickly, but here goes.
If you increase the size of the cylinder to deal with low pressure but at the same time decrease the leverage advantage to get the movement you want, you've effectively negated any gain from your bigger cylinder.
The volume of fluid required may be actually be equal. You need so much movement with so much force and you choose between long thin cylinders with no linkage or short fat cylinders and long linkage. If you only have so much pressure you're sort of boxed in. Or you use massive cylinders to get the stroke and then need a HUGE pump flow to keep the speed of the action right. As time went on pressures have certainly gone up........no question about that.
It does seem that lower pressures are the culprit. You could always just have a bigger pump if flow was a problem. But you probably can't get past seal issues in the pump, more than likely. Higher pressures would require more precise (or expensive, even if possible) machining and design. Metallurgy may have also been an issue. Dirt and corresponding wear would be more critical.
There may have been cylinder seal problems too. Higher pressure would require better seals, and materials could have been a problem there too.
I seem to recall that some of the seals in my Cletrac cylinders are actually cast iron.....like a piston ring.....along with cups?? Mind is failing. But those are small cylinders. They're also newer, maybe the early fifties? Never mind. When were O rings developed?
That's what we need! A hydraulic history expert! Anyone out there?
Even with all that being possible, (remember, I'm just guessing on ALL of this), the linkages seem border line insane. Searching for a better mouse trap? Patent obstacles? Huh?
Then there's this: I worked with an engineer on developing some exercise machines, and he really enjoyed complicated solutions. I mean REALLY complicated. My favorite was his solution for a seat adjustment requiring more levers, pawls, springs, pivots, machining and overall crap than I could ever explain. Rube Goldberg would have been proud. It was an engineering marvel, but totally nuts. We discovered a counter-solution that was a lever, a spring, and some notches on a rod. Maybe they just had bad engineers. Ha!
02-12-2008, 11:44 AM
Think your summary is pretty much on target:D
As far as history of hydraulics, I think it pretty much has its roots in War II.
The old "43" tin can I was on had assorted hydraulic systems, gear pumps, medium pressure hydraulic assisted steering (can't remember the pressure, think it was 1,200 to 1,500 psi.) Aircraft hydraulics was also coming on fast.
For some reason Cat got hooked on vane pumps....which limited pressures.
Believe I read some where there was concern for cold starting loads and the vane pumps offered near zero low speed starting pressures.
Considering some of the early Cat dozer applications and the fact that the #40 scraper was the only crawler pulled scraper to go hydraulic you could hardly say they were innovators in the field. Took a long time to overcome the "cable" mind set I guess.
02-12-2008, 03:46 PM
One of the big reasons for maintaining the operating pressure in the 1000 to 1500 pound range was the state of the art in piston seal technology of the time. There is not a lot you can expect out of horse hide.
02-12-2008, 04:49 PM
Yes, I would agree, seal materials were pretty limited.....but getting back to the original topic there doesn't seem to be much logic for some of the goofy linkage, like the D4 for instance. Didn't take long before that same limited hydraulics was doing the direct blade control on the D6-up in the same era.
Still seems like a Rube Goldberg application (D4) to get a hydraulic dozer mounted on something that was never intended. Didn't take Dakota and others long to figure it out.
02-12-2008, 05:20 PM
You are right, the D-4 linkage is definitely designed by Rube and built by Goldburg. It would be interesting, over a nice cold beer, to hear a retelling of the original design thinking.
Early crawlers were not designed for dozer blades this resulted in the hydraulic rams being mounted outside the track frame and the need for linkages etc. Many large crawlers used cable controlled blades into the 1950s
03-04-2008, 12:10 PM
My D47u came with a Bros dozer from CAT in 1953. It always seemed to me to look much more modern than the CAT built blades. It used longer and smaller hydraulic cylinders so it seems to be the opposite approach. There isn't any strange linkage and it all worked off the standard #44 hydraulic pump. It was my father's understanding that the dozer was built for the military and then released for civilian use as dozers were "rationed" during the Korean war. It's also quite easy to remove the dozer compared to the CAT ones. All you do is pull two pins at the hydralic cylinders and then undo the back half of each pivot point. I think the cable dozers with the wild framework are the strange animals.
03-04-2008, 07:40 PM
I've not seen one like that before. It's definitely going towards a more modern approach, but then it's also a little newer than some of the craziest ones. The Kay Bruner on mine is probably older.......not sure what age but the tractor is a 1937.
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