Comments on: Methods for Gear Attachments http://thesalmonfarm.org/blog/2007/03/26/methods-for-gear-attachments/ Bloggin' down on the Farm - news and happenings from the Salmon Farm. A blog on various topics including my thoughts on collaborative technology, personal information in the 21st century, the global internet (or the lack there of), dog training, cooking, architecture, and whatever happens to be a pet peeve on any given day ! Tue, 06 Jan 2009 02:47:22 +0000 http://wordpress.org/?v=2.7 hourly 1 By: Glen http://thesalmonfarm.org/blog/2007/03/26/methods-for-gear-attachments/comment-page-1/#comment-1102 Glen Tue, 12 Jun 2007 20:50:08 +0000 http://thesalmonfarm.org/blog/2007/03/26/methods-for-gear-attachments/#comment-1102 Hi Alan - yes, as I learned more about the clock, I learned the correct "language". the object which looks like an air-brake is correctly called a "fly" in my later posts. I've also learned, in this particular case, the "fly" serves one primary purpose and one secondary purpose. As you point out, its primary purpose is to keep the legs of the escapement from bouncing when they reach the stops. The inertia in the fly causes it to rotate forward (in my clock it only rotates about 5 or 10 degrees) when the leg hits the stop, and thus keeps the leg in stable contact. The "fly" does has another purpose - though it should never come into play. The "fly" does act as an air-brake in the unfortunately case that the escapement legs jam or get stuck in their extended position. In this rare case, the "fly" will prevent the clock from becoming a run-away and crashing. A flywheel would not provide the added function. thanks for the background and setting the record. Hi Alan - yes, as I learned more about the clock, I learned the correct “language”. the object which looks like an air-brake is correctly called a “fly” in my later posts. I’ve also learned, in this particular case, the “fly” serves one primary purpose and one secondary purpose. As you point out, its primary purpose is to keep the legs of the escapement from bouncing when they reach the stops. The inertia in the fly causes it to rotate forward (in my clock it only rotates about 5 or 10 degrees) when the leg hits the stop, and thus keeps the leg in stable contact. The “fly” does has another purpose - though it should never come into play. The “fly” does act as an air-brake in the unfortunately case that the escapement legs jam or get stuck in their extended position. In this rare case, the “fly” will prevent the clock from becoming a run-away and crashing. A flywheel would not provide the added function.

thanks for the background and setting the record.

]]> By: Alan http://thesalmonfarm.org/blog/2007/03/26/methods-for-gear-attachments/comment-page-1/#comment-1101 Alan Tue, 12 Jun 2007 20:19:15 +0000 http://thesalmonfarm.org/blog/2007/03/26/methods-for-gear-attachments/#comment-1101 What has been referred to as an air-brake or fan-fly is actually not significantly slowed-down by air resistance. It doesn't achieve enough velocity for that to be a major factor. The purpose of it is to "dispose of" the inertia (or excess energy) which is in the escapement arbor (on which it is fitted) when that arbor is stopped in its forward motion by the locking of the escapement. I had trouble convincing people of this until I found, in museum collections, several clock movements by Bond (Boston, mid-19th century)which had gravity escapements and which had small-diameter but heavy "flywheels" instead of large fan-shaped flies. The key (whether it be shaped as a fan or as a small heavy flywheel) is that it is *friction-mounted* on its shaft. and runs forward (typically 90 degrees or so) once the escapement locks; thus converting the left-over kinetic energy to heat. What has been referred to as an air-brake or fan-fly is actually not significantly slowed-down by air resistance. It doesn’t achieve enough velocity for that to be a major factor. The purpose of it is to “dispose of” the inertia (or excess energy) which is in the escapement arbor (on which it is fitted) when that arbor is stopped in its forward motion by the locking of the escapement. I had trouble convincing people of this until I found, in museum collections, several clock movements by Bond (Boston, mid-19th century)which had gravity escapements and which had small-diameter but heavy “flywheels” instead of large fan-shaped flies. The key (whether it be shaped as a fan or as a small heavy flywheel) is that it is *friction-mounted* on its shaft. and runs forward (typically 90 degrees or so) once the escapement locks; thus converting the left-over kinetic energy to heat.

]]> By: Glen http://thesalmonfarm.org/blog/2007/03/26/methods-for-gear-attachments/comment-page-1/#comment-730 Glen Tue, 27 Mar 2007 12:36:07 +0000 http://thesalmonfarm.org/blog/2007/03/26/methods-for-gear-attachments/#comment-730 actually - "thank you". Great questions and I'm glad I took the time to really notice the variations the builders of the clock took and "why". actually - “thank you”. Great questions and I’m glad I took the time to really notice the variations the builders of the clock took and “why”.

]]> By: Roy http://thesalmonfarm.org/blog/2007/03/26/methods-for-gear-attachments/comment-page-1/#comment-727 Roy Tue, 27 Mar 2007 02:53:08 +0000 http://thesalmonfarm.org/blog/2007/03/26/methods-for-gear-attachments/#comment-727 Thanks Glen... Thanks Glen…

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