Spot Turn OC46?

[oliverchris]

When you see Spot Turn written on the side of various OC4 models, is it just advertising the great diff. steering available on all Oliver crawlers models or is 'Spot Turn' something extra?
If the latter, what is it?

[John Schwiebert]

Spot Turn is steering with clutches. The advantage was they turned shorter. More details later.

[Robert Barbour]

Spot trun is a clutch and brake setup like most crawlers have.  On old Cat's they had a lever operated steering clutch and foot brake for each track.  To turn you would pull the clutch and brake as required to make the turn you wanted.  Going down hill you could pull the oposite clutch and let that side of the machine roll ahead if you had no or little load.  With the spot turn system pulling the lever engages the brake which operates the clutch.  So the track is never loose and you can not de-clutch with out the brake.  So turning up or down hill is the same.  The advantage is you can make a shorter turn  than with differential steering, but only with light loads.  With heavy loads with any clutch and brake system when you de-clutch one side all the power goes to the other track, however when the load is heavy that track will often spin and the tractor will stop!  With differential steering you can make a gradual turn with the heavies load the tractor will pull!  You can't do that with a clutch and brake system, often with those you have to back up to turn the tractor so you can go staright ahead with both tracks driving to pull the load.  That is the big advantage of diff steering.

[cletractracks]

i believe the term spot turn refers to the machines ability to turn on the spot, meaning it will turn just like a skid steer loader. my only encounter of this type a machine is a oc-96 owned by a fellow employee. the rear end uses clutch packs operated by hyd. pressure to engage clutches and planetary gears to get reverse etc. you could steer it like a conventional cat by pressing down on brake pedal wich energized a dump vale to drop clutch pack pressure and release power to track. if you pressed further down it engaged a master cyl. wich applied brakes on the rear mounted brake drum attached to the shaft on the clutch packs.  in my opinion it was years ahead of it's time.

[Blake Malkamaki]

You're right about the OC-96 - we had one and I was able to drive and operate it when I was about 7 or 8 years old as it took no physical effort. It was WAY ahead of it's time and a real shame that Oliver ran the company into the ground and these tractors faded into history. There was also an experimental X-12 (aka OC-14) made that was basically an updated OC-12 with very similar characteristics. Landis Zimmerman has one and I was fortunate enough to run it for a few minutes last year at Williams Grove.

BUT, as far as Spot Turn goes... this is not what Spot Turn refers to. Spot Turn is a clutch pack and band steering unit that STOPS one track to make turns. No counter-rotating!

Blake

[cletractracks]

i stand corrected. i only own 1 cletrac and a handfull of cats and i did not realize oliver even made a steering clutch type tractor, but that oc-96 is the hot set-up.