Hi, Folks.
My experince with Cletrac crawlers is limited to watching them in fields as I drove by and seeing one close up as I was walking past on my way to somewhere else.
Can anyone tell me if Cletrac's diff-steer gave full-power turns, that is to say full power on both tracks as the machine was making a turn, a la the modern Cats?
The reason for this question is that some-one at Yesterday's Tractors has made the claim that Case was the first with this feature. I doubt this 'cos Case wasn't even in the crawler business until it bought out Terratrac. I suspect that the early tiller-wheel steer Holts and Bests may have had a diff which would have given them pull power on both tracks while turning. That would be a long, LONG way before Case got into the business.
You have a wonderful day.
Best wishes. Deas Plant.
Yes Deas, Cletrac's Controled Differential Steering applies power to both tracks at all times. Long before Case ever thought about crawlers. Cats do not applie power to both tracks - when you pull the lever and activate a steering clutch you lose all power to that track. Except, from what I've heard, some of the new agricultural Cats have Cletrac steering in them.
Blake
Hi, Blake.
Thanks for your reply. It clears things up for me and proves that some 'experts' on some of these forums DON'T know that of which they write. I wasn't sure so I asked.
Cat have had diff steering on their
'dozers for around ten years now. I think it started with the Cat D6H. Still, it did take 'em a while catch up, didn't it?
Thanks again.
You have a wonderful day.
Best wishes. Deas.
Your friend that talked about the case with the differential steering, well the first Clark /terratrack used a Clark final drive same as the Cletrac HG. This looking at history was a World War two thing to keep up with the war. Cletrac had this before .
Hi, John.
So TerraTrac had the diff steering before Case bought them out and Case inherited it with the purchase of TerraTrac. Is that correct? If so, I will take a certain amount of delight in directing certain 'experts' to this thread.
Thank you.
You have a wonderful day.
Best wishes.
Deas Plant.
Well if the truth were told Cat sort of had the diff steering first. It happened this way. In 1915 the C. L. Best company build their model 8/16 with new differential steering. They showed it at the San Francisco exposition in 1915 and a fellow named Rollin White of the White Sewing Machine company in Cleveland saw it and liked it. He purchased the tractor and the right to it from C L. Best who was in financial hard times, and started the Cleveland tractor company. Later in 1925 C.L. Best and Holt joined to form Caterpillar.
Robert, where did you get this information?
From what I was told by my grandfather, Rollin White invented the steering used in Cletracs. Cletracs use what is called "Controlled Differential Steering" where, when you pull the lever (or steering wheel on early models), the drum that the brake band is wrapped around stops, allowing the plannetary gears inside to reduce the speed of that side of the tractor and proportionally increase the speed of the other side. Therefore the tractor's ground speed remains the same.
I would like to know what the early Best steering did and how it worked.
A couple of years ago I did a little research for the Tru-draft Tractor folks. That is the General-B. F. Avery and then Moline which alldesended from the Cletrac general. Unlike the rest of the Cletrac line they purchased this differential from Clark Transmission. Durring the War there was also a Clark dozer (Military) almost a twin to the HG. Well Dana purchased the rights to Clark from I-R and so I had a gentleman send some information on the final drive. It was available with steering with planetary for a crawler and a plain differential for a wheel tracor. They made those units for over 20 manufactures, One being Case.
I got this information from a book on Caterpillar by Robert Pripps called The Big Book of Caterpillar. I don't think Best invented the differential either, just that he was the first to use in a tractor. The Cletrac differential is not a planetary, it is a differential like is used in a car except the gear arrangement and type( spur gears) is different so it can handle the much heaver Torque load. Actually the proper term for a differential is a Torque Divider. In a car the torque to each wheel is always the same but the speed may be different. With a brake controlled diferential the Brake consumes some of the torque going to one axle, it slows down and the other speeds up by the same amount. The engine load also increases as some of its power is wasted in the brake.
Hi, Folks.
Thanks for all the information. The plot thickens and still there is little new under the sun. Would it be permissible to copy this thread and post it at Yesterday's Tractors where this discussion really started. I brought the question here because I knew Cletrac had differential steering but didn't know when they started using it.
Alternatively, I could post a link to this thread on the Crawlers forum at YT.
You all have a wonderful day.
Best wishes. Deas.
QuoteI got this information from a book on Caterpillar by Robert Pripps called The Big Book of Caterpillar. I don't think Best invented the differential either, just that he was the first to use in a tractor. The Cletrac differential is not a planetary, it is a differential like is used in a car except the gear arrangement and type( spur gears) is different so it can handle the much heaver Torque load. Actually the proper term for a differential is a Torque Divider. In a car the torque to each wheel is always the same but the speed may be different. With a brake controlled diferential the Brake consumes some of the torque going to one axle, it slows down and the other speeds up by the same amount. The engine load also increases as some of its power is wasted in the brake.
The original term for a differential was a compensating gear and steam tractions engines had them in the mid to late 1800s.
The Cletrac Controlled Differential Steering IS planetary. The drums stop completely when the lever is pulled fully. No energy is consumed by the brake and no heat or wear is created by the brake as long as the brake is fully activated. Other than friction of the force needed in turning the tracks in the dirt, there is no power wasted to the brakes.
Blake
Deas, Rollin H. White used the Controlled Differential Steerin in the model R tractor built by the Cleveland Motor Plow Company in 1916. I'm not sure when he developed it.
O. K. I did this several years ago when I was in Cleveland on business. I checked on some early Cletrac pattents. I am sure enough of us have read where Rollin developed this " tractor" that carried the tillage tool. Now we are all in agreement that the Model R was the first Cletrac, so designated because Rollin started with the letter R. I think we have all seen drawings. pictures whatever where on the side of these things (Model R) it has the name Cleveland Motor Plow Company. Here is what I don't understand. Rollins pattents for his tractor which carried the disk was assigned to the Cleveland Tractor Company. So when did Cleveland Tractor really come into being, if those pattents were assigned to Cleveland tractor in 1914. Another thing, Rollin was granted a pattent for a direction changing device, which I think could be shifted on the go in1920. It was also assigned to the Cleveland Tractor company. Now did they ever use it because it would have been great with a dozer, no clutching! Next odd thing in the late 1920's they were developing a 2 stroke diesel to go into the model 30. The design of the engine except for the fuel system is very similar to a 71 Series Detroit. Was this design sold to Winton who was a forerunner to Detroit Diesel? Winton engines was also in Cleveland
In another book I have It say the Cleveland tractor company, the successor to the Cleveland Motor Plow company was incorporated in 1916. Now if Cleveland tractor had patents in 1914 then these books are not exactly accurate are they!! That would not be a big surprize to me as tractors have become quite popular in the last few years and the publishers are trying to cash in on it with anything they can get to market fast. Now as for planetary gears, they are not differentials , planetary gears are used for the reduction and reverse in automatic transmissions. Brakes always consume energy when ever the think they are braking is in motion, Even in a Cletrac!! It is not often that you are able to stop one track completely so that no energy is consumed!
QuoteNow as for planetary gears, they are not differentials , planetary gears are used for the reduction and reverse in automatic transmissions. Brakes always consume energy when ever the think they are braking is in motion, Even in a Cletrac!! It is not often that you are able to stop one track completely so that no energy is consumed!
Robert, you don't understand how these work. The steering drums do have planetary gears in them. And the brakes do not absorb energy if they are not slipping. The brake bands hold the drums from turning - no friction = no loss of energy. And Cletrac steering does not STOP one track!
The Cletrac uses Controlled Differential Steering. It is not a differential as you know it such as in your car. And it's not simply like putting the brake on one side on a rubber tired farm tractor.
John, the company was called Cleveland Motor Plow Company until 1917 when it became the Cleveland Tractor Company. The term "Cletrac" came about in 1918. Rollin was designing tractors and other machines before he formed the company. He was also involved with his brothers White Motor Company and White Sewing Maching Company.
Yes Rollin designed the two cycle diesel engine. I am not sure about the Winton connection, but it could very well be true. I will ask my uncle if he remembers.
Well Blake I think you are the one that does not understand! The Cletrac uses a differential that functions the same as one in a car, but it also has a brake that has been added. This brake is geared from the pinions at a different ratio than the differential pinions to axles are. When the brake is full on so that the drum stops the slow axle does not stop as you have said. That arrangement limits the speed difference( that can be produced by the brake) between the axles and the turning radius of the tractor. It also makes the brakes more effective. However if you put a cletrac in a position such that one track was on solid ground and one on ice. The one on the ice would spin just like a car. If you looked into the Cletrac differential while doing this the brake drum on the side that was stopped would be turning in reverse!! And again there ARE NO PLANETARY GEARS IN A CLETRAC!!
Robert you are wrong on this. The only Cletrac that uses a differential like one in a car is the General - which is a wheel tractor.
Someone needs to get you a copy of a drawing of what's in the steering brake drums. Yes - planetary gears! That is the whole concept of Controlled Differential Steering!
And I never said one track would stop completely.
Just found this one. You fellas might like to take a look at it:
http://photos.groups.yahoo.com/group/ca ... yahoo.com/ (http://photos.groups.yahoo.com/group/caseterratraccrawlers/lst?.dir=/CASE+PICTURES&.src=gr&.order=&.view=t&.done=http%3a//briefcase.yahoo.com/)
It has two schematics, one of a 60's Case 310 steering mechanism and the other of a 1933 Cletrac. Left click for the larger view.
You have a wonderful day.
Best wishes. Deas Plant.
Hi, Blake.
Is it possible to post an active link with a post here? If so, how do we do it?
You have a wonderful day.
Best wishes. Deas Plant.
Good Morning all, here is a scan of the parts brakdown on my oc-3, I see a plantery set not just spider gears like in a car. Hope that this is some help.
Ron
Thanks for posting this Ron. I have not had time lately to look up a breakdown picture like that. Your's says it all.
Here is the picture from Deas Plant, showing how the Cletrac Controlled Differential Steering works.
Blake
That is an excellent exploded view of the cletrac differential. I have a scanner on order and when I get it I will post a view of a planetary gear train so you can see the difference!!
Robert,
I look forward to see what you are calling a planetary gear train, the two pictures posted are what I have called planetary for the last 35 years or so, and the parts list that goes with the brakdown that I posted refers to the gears as planet gears, and planet pinions.
Ron
I just drove my W and i did research on the steering. All the brake bands do is hold the drum wich causes a gear reduction in the planetary wich only slows the speed of the one track which allows the tractor to turn. A planetary only increases torque and has a speed reduction. This machine does not turn like a farm tractor it is much smoother.
I think Justin's description of operation is good, however, while the inside track is slowed by brake/planetary engagement, it also proportionatly speeds up the other track which is why this steering system is so smooth. The amount of energy used by the brake is directly proportional to the ground friction being overcome while turning, minus the gearing advantage of the planetary set. If the tractor were in a concrete channel, assuming perfect traction, locking one brake would stall the engine. Note that locking both brakes while in gear does the same thing. To be continued. TEDV:):)
I now have my scanner and once I work my way through the soft-ware I will post the material I have gathered the past few weeks. I have a good discriprtion of the use of planetary gears in GM automatic transmissions, the planetary used in the Cat D5H, and the inter axle differiential used on some Rockwell rear axles. This is the same setup used in the Cletrac!
Also note what is written below the picture of the OC 3 drive posted by pvcarey(Differiential) not planetary!!
Here is the first part on the Planetarys from the GM transmission book, I hope!!
I re-sized the files so will try again!
Please Robert, it's not necessary to upload your GM transmission pictures. I'm not sure what point you are trying to make, but I feel it is just a misconception of terminology. If you want to send your pictures, please send them directly to me first.
Blake
Just to throw a littl fuel on this fire, I have a Studebaker M29C Weasel, which is an amphibious crawler cargo and personnel carrier from WWII. It has the same Clark controlled differential in it, but has a two speed gearbox for high and low range built into it.
The gears, brakes and most internal parts interchange with the OC-3 differential.