How does a tucker front axle turn?

[berg]

Curious to know how a Tucker front axle turns the front end.
Never been up close to see the mechanics of it... does the whole front axle
pivot or do the pontoons pivot on the end of the axle housing like a normal 4x4?
The reason I wonder is is seems like there would be an enormous amount of stress turning on the inner CV or inner axle joint.
This is all assuming a tucker does not use a track braking system... right?

In the pic below it looks like the whole axle is turning...

school me

 

[ve3otk]

Have only seen a Tucker 2000. The axle assemblies turn above the differential housing. Front and rear assemblies both turn. On the 2000, the leaf springs mount to a large plate and the plate turns. Since the plate with the leaf springs turns, the axles underneath turn.

 

[berg]

so the whole pinions ( third members/housings) turn .... is that what your saying?

seems that would limit your turning radius ....right?

 

[Lyndon]

Due to the fact that they steer BOTH the front and rear sets of Pontoons, they actually steer fairly sharply. NO differential Braking means that the tracks get power at all times making them very agressive. On Steel Track Tuckers the front set of tracks had an additional pivot that allows the front to tip sideways independant of the rear and body. I don't know if the later models had this feature. All the 2 track machines tend to tear up grass if they turn, acting almost like a roto-tiller. It's tough on whatever steering method, and on the tracks and drive sprockets. Most larger Ski Areas have at least one Tucker to access the upper slopes in the spring, for spring skiing, so that they can get across the bare lower slopes without causing as much damage to the grass and ground cover, which in turn limits soil errosion on the ski hills. Their method of turning also makes the tracks and drive sprockets last longer. This in turn leeds to lower maintenance costs. At least one study indicated that they were the least expensive to operate per groomed mile, than any other groomer.

 

[Briarpatch]

The tuckers use what is called a 5th wheel plate for both the front and rear assemblies. The entire assembly rotates/slides when the steering wheel is turned. The one steering cylinder is hooked up to the swing arms which move in opposite directions moving the tie rods and plates.

The 1976 1644 that I have has a stell plate in the front and an aluminum plate in the rear. The front plate was set up for a plow when it was ordered new in 1975.

Briarpatch

 

[ve3otk]

Think of the Tucker as having articulating steering without the frame doing the articulating. When the steering wheel is turned to the right, the front axle assembly is turned to the right and the rear is turned to the left.

Take a look at some of the manuals at: http://www.goldcordmine.com/manuals/TUCKER (4 manuals)/

Look at the pontoon manual, figure 7. This shows the steering mechanism. The hydraulic piston (item 1) swings steering swing (item 2) forward for a right turn and backwards for a left turn. Item 8 is the tie rod that turns the front axle assembly. On the other side of the tucker is another tie rod for the rear axle assembly. Figure 7 is looking at the left side of the Tucker.

Figure 8 is of the rear axle assembly. Item 8 (tie rod) pushes/pulls item 2 to turn the rear axle assembly.

As the axle assembly turns, the U-Joints have to deal with the horizontal missalignment along with the vertical missalignment.

Newer Tuckers do not have the fancy cast metal (item 3 + 4 in figure 8), just a big plate and I think there is some teflon in there somewhere - never took a real good when we had the rear carrier off last year on the club's Tucker 2000. Can't take pictures to show better as the club's Tucker is out in the bush minus the left rear track.

 

[berg]

So the Tucker use the fifth wheel plates that actuated by hydraulic rams attached to the frame and plates.... is this picture similar to what the steering gear would look like?... or were the early ones mechanical..

Not sure where I got this pic ... it might be a tucker.
just curious of how those big pontoons move .. A lot of force exerted there IMO

I noticed in another thread BrokenGrousers Older Tucker 443 had the steering going straight down thru the firewall and I wondered how those early rigs turned...

 

[mtncrawler]

The early ones had what amounted to a power steering pump with an oversized reservoir under the hood belt driven off an engine pulley which produced hydraulic power for the steering ram. The contact areas where the plates supported the body were replaceable brass bushings. Getting the pontoons to steer isn't as bad as you would think, it gets easier once you get a little speed up.

 

[mtncrawler]

I have also seen a Tucker where the steering wheel operated only the front turntable and the rear was controlled with a lever. This setup allowed the operator to steer both turntables in the same direction and the machine would "crab" along, packing down snow the full width of the machine. Don't know if this was a factory option or owner modification. This Tucker had the blue fiberglass widetrack pontoons and last I knew it went to Wyoming.

 

[MountainMike]

Howdy Berg,
Doc sent me an email asking where I've been. Just been busy with work these days.

Hey, you guys did a great job of "Talkin Tucker" as I say, and discussing the Sno-Cat steering mechanism. As some of you may recall, I own a few vintage Tucker Sno-Cats (you may remember "Let It Snow"; my December Post about my Tucker 442A restoration).

The steering on a vintage steel track Tucker is quite something. The two 5th wheels (nick named "turn tables" (tt)) operate the front and rear sets of pontoons independently via a hydraulic ram and the swing arm underneath which pushes two tie rods attached to the tt's and articulates the tracks underneath the machine in opposite directions when turning the steering wheel. Amazing mechanical functionality if ya ask me. Tucker sure had one hell of an idea when he invented his machine!

I tell you what, I can swing the back end of my tucker around real quick on a down hill turn with that steering system. Or, hold a tight turn going over the crest of a tall snow drift in the back country. And, snake my way through a stand of trees when the going gets tight. It's a real hoot to drive one!

Anyway, my compliments to your discussion of the Tucker steering.
Thanks for Talkin Tucker!
Rocketman

 

[srexecmark]

With a Tucker you have to moving to steer. On real sharp turns sometimes you have to back up and steer the tracks where you are going to need them going forward while you back up. Hard to explain...it is something you just learn after a while.