LTM shutter rapture ;)

[schattenundlicht]

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This will be old hat for you, but I can still get carried away by the mechanical wonder of the original curtain shutter and the incremental improvement it underwent. Please be lenient towards a relative newcomer to LTM innards

 

iPhone slow motion of IIIa timing mechanism:

 

http://www.galerie-elsner.de/video/IIIa.MOV

 

[ The video file is 8 MB, so those on a mobile or on a slow internet connection might refrain from clicking the link ]

 

 

This is from the original German patent published in 1926 (declared valid as of 1924):

 

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Edited July 2, 2018 by schattenundlicht

[schattenundlicht]

Since the patent description may lead to spurious results in Google Translate, I offer the text of the corresponding 1927 US patent, instead:

 

! Spoiler: They changed the caption numbers from the German to the US patent, see further below !

 

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Edited July 2, 2018 by schattenundlicht

[schattenundlicht]

The wonderful description should not break off in the middle of a sentence, so here is page 2:

 

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Edited July 2, 2018 by schattenundlicht

[schattenundlicht]

Now that I have realized, that for the US patent all the caption numbers were changed, as a gesture of fair play, I enclose the US version of the line drawing, adding the benefit of having a glimpse at Barnack's cute signature (in US patents of that time, the inventor was the titular, whereas in Germany, the company was the titular to a given patent):

 

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[schattenundlicht]

Source: The patents were retrieved via DEPATIS, the patent research database of DPMA, the German "Deutsches Patent- und Markenamt" (the government body regulating patents).

[willeica]

Thanks Mathias. Some of these and many others in both German and English are included in a 42 page section at the end of the book, 'Oscar Barnack- From the Idea to the Leica', published by the LHSA. The book, which  was translated from Uli Richter's original book in German by Rolf Fricke, is essential reading for anyone interested in early Leicas.

 

William

[schattenundlicht]

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Thanks Mathias. Some of these and many others in both German and English are included in a 42 page section at the end of the book, 'Oscar Barnack- From the Idea to the Leica', published by the LHSA. The book, which  was translated from Uli Richter's original book in German by Rolf Fricke, is essential reading for anyone interested in early Leicas.

 

William

Thanks, William, for the reference to Richter’s excellent book which I am happy to own in the German language edition. It is indeed sort of „required reading“ but I thought that maybe not everybody in his forum does own a copy. This might have been a bit naïve of me In hindsight, I could have omitted this thread.

 

The patent documents themselves are in the public domain. I recently dug out more than 50 prewar patents, many of them not included in the Richter book, and some showing solutions that never made it into actual production, whilst other patents preceded their implementation in manufacture by more than a decade. Quite interesting.

 

Kind regards

Mathias

[Bateleur]

Rapture indeed, though I have Richter's book your video adds to the fascination of the shutter's mechanics.

 

Thank you.