This Traction Control was offered by Cat as an option on all 3-axle tractor-scrapers in the sixties : 630B , 650 , 660 , 666 . I had never heard about this system in 50 years , but I came across at a scale model of the 666 , bought by a relation of mine . He wondered the function of the 2 hydraulic cylinders on the floor of the tractor ( see pic) . When I browsed my files I read about this system , but I never saw one or heard of it during all the time . I am surprised by the scale model makers who are also not aware of the function of this system , and so do most model collectors as I noticed . The system can put more weight on the tractor drive wheels , taking weight from the front axle or even lift it from the ground in order to improve traction . . There are several model makers who equipped their 666 models with it , probably they recklesly imitated the machine out of the parts book . So , I think there are more scale models with traction control than real ones . Are there any operators or others who have known this system , or is it a great mystery ? Let us know about your experience !!!
There was a discussion about them over on the ACMOC board a while back.
I also saw a system like this advertised on some very late DW20's called Tractionaiders. The ones you described were an option, how popular I don't know. Described as an option in my 600 series literature. I have a friend who worked for JA Tobin in the Kansas City area, who described using it to help load. The folks I used to work for had some 632's (630 with 641 sized bowls) and they could also be used to act as a sort of ride control. If abused they caused trouble and may have been removed from some units. I hope this helps.
Yair . . . While we are talking about the 666 what did cat call the electric shift transmission . . . and can someone explain just how it worked. I roaded one near Mt Isa and they just shoved me on there and told me to let it do its thing. Cheers.
Thanks alan627b , I did not know about that traction control on the good old DW20 . I am 60 years in heavy plant but every day you learn something . Yes , in the literature of the 3-axle 600's the traction control is mentioned as an option . Hello Scrub Puller , what do you mean with electric shift transmission ? On the old DW21G there was such a transmission available as an option . The transmission was shifted by solenoids . This was the forerunner of power-shift . If this is what you mean , let me know . Cheers
Yair . . . johan7 . As I understand it was basically the standard mechanical stick shift transmission and the clutch and shifting was controlled by solenoids and air. I don't think it was all that successful. Cat had some fancy name for it and I have been trying to remember it for years . . . you are the first one to have even heard about it or at least responded. (big grin) Cheers.
Selectomatic, or something like that?
It was called SYNCHRO TOUCH and was available on the DW21 . I have a rather good experience with this system . The pic shows the lever that came in place of the stick . The foot pedal was only used for moving from a stand still . The system used electrics to control hydraulic valves that moved the shifter forks .
Here is a pic of that transmission system . Cheers
Yair . . . johan7 . SYNCHRO TOUCH it was!! Thanks for that. So it was a DW21 I roaded . . . all these years I been telling folks a 666 . . . ah well. (rueful grin) Cheers.
Scrub, before my time, but I know that Thiess had at least one DW20 fitted with it. Apparently it went well for a while until the dirt started to do it's work and then gave constant trouble. They ended up putting a standard shift back on the machine, I'm told they gave the electrics to Qld University to play with.
That front end lift works great in close quarters. The 666 turns into a 657 at this point, easy dumping. Mike Nebergall X Quad Operator
Thanks Mike , that is an interesting mail , problably you were able to steer the tractor with the front end lifted . But , please explain how you made that turn , braking one of the wheels ? We are eager to hear about it . Have a nice day . johan7
Good-morning, johan7. Turning-brakes. I always slipped the transmission into 1st gear first lifting the front end up then I'd turn one way or the other using the turning brake handle--remember there was 0 visibility with the width of hood and the front fenders--you could turn fast or slow using the turning brakes. It also was a neat feeling watching the look on someone's face as you maneuvered around. Mike Nebergall X Quad Operator
Thanks Mike , Your way of making a sharp turn is a rather spectacular circus act ! But I agree in tight places it will work . I once studied the specifications of these scrapers in making turns and I found out ( reading the Cat spec sheets ) that the 3-axle pans could make a sharper turn than 2-axle units under some conditions . For instance : a 657 has a turning radius of 16,1 m (left) , 13,4 m (right) , while the 666 , which is 2 m longer ,has a radius of 14 m . The difference with the 2-axle units is caused by the cab . My question : When you make a sharp turn , is the angle between tractor and scraper more than 90 degrees ? And if so , to my opinion the scraper wheels turn backward for a moment . Is that right ?
JOHAN7. According to Caterpillar specs----the 657 turning radius is 47' 10" (14,58 m) where the 666s turning radius is 46' (14,02 m). I don't think it would be anymore than 90 degrees, all I know is you can only turn as sharp as the stops will allow. On a single engine scraper tire I've seen them turn backwards. Now on the twin-engine scrapers, I know the tractor driver tire doesn't turn backwards, I don't think the scraper tire turn backwards either on a jackknife turn because the locks on the inside of the rear-end won't allow that. Does this help! Mike Nebergall
I run a 660 with traction control.It was designed to lift the front of the machine off the ground and put more weight on the rear wheels when loading.Only time that was possible on my job was none.We were hauling out out a 20 acre barrow pit on the Missouri river bottom.The top 5 foot of dirt was old slimy gumb.With 4- D9s behind loading you it was all you could do to get enough traction to keep the front end going straight. Usually had to straddle a ridge to keep in a straight line if you couldn't keep it going straight then you was in trouble.You would get jackknifed and with all the D9s behind you it was hard to get them stopped in time to keep from ripping off the air cleaners,if you was lucky enough to get turned that direction.They wasn't much fun in mud. After we got the mud off tho they wasn't bad, pure sand then, with three 8" pumps pumping 24-7 to help keep the water out of the pit.Start of the day the pit was dry ,by noon with 30 scraper running in it there would be 2 foot of water you would be trying to load in.Had to watch over on the banks of the pit to tell if you was moving or not because if you just watched the water you couldn't tell if you was moving or not. Usually got half a load of sand and half a load water.Believe it or not when the water run out of the sand the haul road was like concrete to haul on.You could fly down it with a full load as fast as the old 660 would run.Until you got down to the fill then it was time to have more 9s behind you.This job was on I29 north of Nebraska City.All those little lake looking things along I29 was our barrow pit.Good times As far as the traction control most of then didn't work or was removed.Not a bad idea if you was working in good dirt,but with 4-D(s behind you who needs traction control.
Construct'O who were you working for on that I-29?
Hello Mike and Construct'O , thanks for the answers and the interesting stories . The Netherlands , johan7
VanBuskirk out of Sioux City.They worked on the Rathburn Dam with the 660s(4) i believe they was new at that time.Also worked for them at Ames Iowa doing highway 30 bybass around Ames around 1970 + 1971.
Somehow I find it humorous that VanBuskirk got the bypass project in Ames Const home town. I would have hated to be the Ames estimator.