What you can do with rotation...
Discussion
Wonderful intermittent-motion mechanisms! Several brought back the memories: We needed a motion device capable of rotating a very heavy turntable 10 feet in diameter within a gas-fired oven at high temperature, the motion consisting of segments of 1/60 rotation every 4 seconds. The turntable supported 58 steel mold carriers each weighing 60 lbs. One second of time was allowed for movement, followed by 3 seconds of "dwell time", during which the turntable was to be held immobile, and having minimal "overshoot" when beginning to move, or stopping. Numerous "Geneva-Mechanism" concepts were considered, until we found the Ferguson Machine Corp. which designs and builds intermittent-motion devices based on a "captured-cam" technique; their devices are named "Intermittors". The unit driving our turntable was the largest they produced, about the size of an average housewife's kitchen stove!
The other memorable comparison involved proving a teacher wrong! Attending college, our Calculus textbook mentioned, under "Simple Harmonic Motion", that pistons in an internal combustion engine move in SHM. One young man raised his hand, declaring that was not the case. The Professor, who surely should have known better, dismissed the claim of error in the text, but the young man persisted after class, privately, with the Instructor. The next day, he took time to commend the young man's astuteness, explaining by way of diagram, that the usual scheme of connecting pistons to a crankshaft does NOT produce SHM! (Several of the mechanisms in the video above accomplish SHM using a rotating crankpin, within a lateral slot, to produce true SHM; such a contrivance is called a "Scotch Yoke").
Ah, the nonsensical world of memories! impish
The other memorable comparison involved proving a teacher wrong! Attending college, our Calculus textbook mentioned, under "Simple Harmonic Motion", that pistons in an internal combustion engine move in SHM. One young man raised his hand, declaring that was not the case. The Professor, who surely should have known better, dismissed the claim of error in the text, but the young man persisted after class, privately, with the Instructor. The next day, he took time to commend the young man's astuteness, explaining by way of diagram, that the usual scheme of connecting pistons to a crankshaft does NOT produce SHM! (Several of the mechanisms in the video above accomplish SHM using a rotating crankpin, within a lateral slot, to produce true SHM; such a contrivance is called a "Scotch Yoke").
Ah, the nonsensical world of memories! impish
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