Image:Stackfreed.png

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[edit] Summary

Description

Drawing of early watch movement with stackfreed mainspring compensating device. The stackfreed is the eccentric cam near the top, engaged by the long springloaded roller arm. It's purpose was to compensate for the decline of the mainspring's force as it unwound. Early in the watch's running period, when the mainspring is fully wound and providing maximum torque, the stackfreed roller rests against one side of the depression in the cam, exerting a force which opposes the mainspring. Later in the running period, when the mainspring is almost run down and is providing less torque, the stackfreed roller rests on the other side of the cam notch and it's force aids the the mainspring. The dumbbell-shaped device under it is the watch's primitive balance wheel, the foliot. The adjoining source text seems to refer to this as a watch made in the 16th century, from the Soltykoff Collection. Alterations: removed caption, sharpened, converted to PNG.

Source

Downloaded from Nelthropp, Harry L. (1873) A Treatise on Watch-work, Past and Present, E.& F.N. Spon, London, p.60, fig.3 on Google Books

Date

1873

Author

Harry Leonard Nelthropp

Permission
(Reusing this image)

Public domain - author has been dead more than 70 years


[edit] Licensing

Public domain This image (or other media file) is in the public domain because its copyright has expired.

This applies to the United States, Canada, the European Union and those countries with a copyright term of life of the author plus 70 years.


Note that a few countries have copyright terms longer than 70 years: Mexico has 100 years, Colombia has 80 years, and Guatemala and Samoa have 75 years. This image may not be in the public domain in these countries, which moreover do not implement the rule of the shorter term. Côte d'Ivoire has a general copyright term of 99 years and Honduras has 75 years, but they do implement that rule of the shorter term.


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File history

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Date/TimeDimensionsUserComment
current23:48, 5 December 2007462×460 (13 KB)Chetvorno ({{Information |Description=Drawing of antique watch with stackfreed mainspring compensating device. The adjoining text seems to refer to this as a watch made in the 16th century, from the Soltykoff Collection. Alterations: removed caption, sharpened, c)
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