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Len Rahilly
10-10-2007 14:49:37
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Re: quick question in reply to marty johns, 10-02-2007 18:17:42
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I remember when "live PTO" came out (in about 1947, on the Oliver 77 and 88, if I remember correctly) and it was considered a big deal. The standard PTO was driven from the transmission, and stopped if the clutch was pushed in. This was a real nuisance if you were pulling a machine like a combine and just wanted to halt the tractor for a second or two to clear out an overloaded cylinder on the combine. You can imagine a number of machines where this would be convenient (Bush Hog, sickle-bar mower, for example). The same thing could be said for live hydraulics. Most of the power lifts before live hydraulics were driven from somewhere BEHIND the tractor clutch. Push the clutch in and the lift stops. If you were cultivating corn in a field with fences, and you wanted to get right up to the end of the row, you had to stop the tractor, shift to neutral, engage the clutch, raise the cultivators, shift back into gear, etc. There have been several ways of making a live PTO work out, including, as I remember, a hollow clutch shaft with the PTO shaft inside it. The main clutch in this rig had two disks, and what you disengaged depended on how far in you pushed the clutch pedal. It's been a long time, so don't quote me on any of this.
Live hydraulics and live PTO are both wonderful, and I always wondered why it took so long for tractor manufacturers to get there. I think there were a few power lifts in the late 20s, and lots of them in the 30s, but none live. Guess the engineers didn't spent too much time actually using what they designed. Well, I shouldn't complain too much. I've lifted heavy machines by hand (IHC 7-foot sickle bar) and I've lifted some with a hydraulic lift (IHC 2-row cultivator on F-12), and I never complained too much about having to shift to neutral for a second. But I was a kid who wanted to "get a lot of work done." Today, I'd probably shift 'er to neutral, throttle back, look around at the blue sky, smell the earth, maybe sit under a tree for 10 minutes with my Popular Mechanics, then amble back to the beast--which I'd then have to crank and have at least something to complain about!
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