M47 PATTON TANK PLANETARY GEARS PRINCIPLES AND OPERATION 85464
162,315
Published 2016-06-14
A U.S. Army training film circa 1953, the first of a two part instructional video describing the advancements of planetary gears (used in the newer tanks such as the M47 Patton) as compared to the older system used on such tanks as the M-4 Sherman. A technician demonstrates the principles of operation governing multiple sets, while a narrator gives a short review of how the planet-carrier gears work. Features original footage of tanks performing tests and exercises as well as the demonstration on a planetary gear model. This video was mainly used to instruct tank drivers during the Korean War about their vehicles and its gear mechanisms.
The M47 Patton is the second American tank to be named after General George S. Patton, commander of the U.S. Third Army during World War II and one of the earliest American advocates of tanks in battle. It was a development of the M46 Patton tank mounting an updated turret, and was in turn further developed as the M48 Patton.
An epicyclic gear train consists of two gears mounted so that the center of one gear revolves around the center of the other. A carrier connects the centers of the two gears and rotates to carry one gear, called the planet gear, around the other, called the sun gear. The planet and sun gears mesh so that their pitch circles roll without slip. A point on the pitch circle of the planet gear traces an epicycloid curve. In this simplified case, the sun gear is fixed and the planetary gear(s) roll around the sun gear.
An epicyclic gear train can be assembled so the planet gear rolls on the inside of the pitch circle of a fixed, outer gear ring, or ring gear, called an annular gear. In this case, the curve traced by a point on the pitch circle of the planet is a hypocycloid.
The combination of epicycle gear trains with a planet engaging both a sun gear and an annular gear is called a planetary gear train In this case, the annular gear is usually fixed and the sun gear is driven.
Epicyclic gears get their name from their earliest application, which was the modeling of the movements of the planets in the heavens. Believing the planets, as everything in the heavens, to be perfect, they could only travel in perfect circles, but their motions as viewed from Earth could not be reconciled with circular motion. At around 500 BC, the Greeks invented the idea of epicycles, of circles traveling on the circular orbits. With this theory Claudius Ptolemy in the Almagest in 148 AD was able to predict planetary orbital paths. The Antikythera Mechanism, circa 80 BC, had gearing which was able to approximate the moon's elliptical path through the heavens, and even to correct for the nine-year precession of that path.
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This film is part of the Periscope Film LLC archive, one of the largest historic military, transportation, and aviation stock footage collections in the USA. Entirely film backed, this material is available for licensing in 24p HD and 2k. For more information visit www.PeriscopeFilm.com/
All Comments (21)
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Amazes me how well these old army films explain things... far better than any CGI video I’ve seen !!!
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These old films are excellent for teaching our youth! As a retired patent agent and avid techno-geek, I am constrained to quibble with the interchangeable usage of two terms that have different meanings; it is surprising that nobody else has caught this little faux pas in nearly 6 years. In the first example, at 2:36, the sun gear is said to revolve, when it never revolves, but rotates about its own axis. Same issue beginning at 3:23, where the terms "revolve" and "rotate" are used backwards. Something rotates only about its own axis and revolves around any axis other than its own; thus, only the planetary gears can revolve, while all the gears can rotate. The error is repeated sporadically throughout the video. But aside from my technical nitpicking, it is well made and an excellent teaching tool that doesn't rely on cartoons, sound effects, or background (which can be annoyingly distracting).
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Thank you for saving, restoring, and posting all these valuable pieces of memorabilia which are also very educational. Ciao, L
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This presentation is actually very good. Not all are. Some,though modern,just don't communicate all that well. This one does. It demonstrates a lot,and in a very comprehensible way.
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As a millwight, I find these very educational. Gearboxes are usually just throw away now days. Or, rebuilt by some other companies. Not, that we have any of these types but, it's just good stuff! I really appreciate it and thank you for sharing with me and everyone else.
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When there is an input and output but no reactionary you get neutral idling. When the Planet Carrier is output and another element is reactionary you get reduction. When the Planet Carrier is input and another element is reactionary you get over drive. When the Planet Carrier is reactionary and other element are mobile you get reverse When two members are locked together you get direct drive with both the input and output shafts rotating at the same speed.
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Why are these old films so much better than the new ones?
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One more video explaining how they work when compounded together in various ways and a calculation of the compounded gear ratios, and voila, now you can understand any automatic transmission! So well demonstrated and explained!
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I have learned more from this 1 vid than I have in years on this type of transmission.
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This is literally what they teach engineers in third year at my school. I'm using it to study for a test.
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I had to rediscover this gem. I am happy that this is still available. YouTube University is available for a PhD
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Understanding planetary gears is important to getting to know about automatic transmissions. The "wild" thing is: The Model "T" Ford (a car FAR from having automatic ANYTHING!) used a planetary gearbox! As primitive as a car could get, but had this concept YEARS ahead of it's time!
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best movie i ever watched on youtube
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❤❤❤❤❤ These videos are really educational and easy to understand. Excellent teaching.
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Excellent tutorial Beautiful video 👍👍👍
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I think our brain absorbs better information when taught with black and white videos, honestly 1930s learnin videos are far better than todays cgi’s
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Thanks periscope for this video i completely enjoyed this video
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This is old, but still amazing. Thank you for this video.
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A great video. Very informative w FACTS
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This is really an educational video. It holds you up by its clarity of ideas expressed.
