Is this a war time Petromax?

Thanks Wim. The fact that the rib/fin existed in this position on the old AIDA lamps hints to the existence of an even older patent, probably registered by the AIDA company.

Or maybe they made it like this for a few years before registering a patent?

 

I was reading the article on AIDA posted on your website http://petromax.nl/AIDA/Aidagesellschaft_uk_24Nov2013.pdf and there is a picture from the patent filled in 1951 for this fin/rib. The one in the patent is much smaller then the one on my lamp, being pretty much identical to everything I've seen on early post-war Petromax lamps (even the much later Chinese copies pretty much reproduced the fin in this patent).

Maybe at some point they decided that making the upper vaporizer too strong wasn't going to help the post warranty sale of spares?

 

Adrian, did you download and read the 1951-1953 patent text ?
In the text it says why they did what they did. So for what reason do you still speculate about warranties etc ?

The big rib was to prevent bending, but took away to much heat. There fore they put it on the mantle side. This position was however limited in space due to the mantle.

All lantern as of 1952-52 would have the small rib.
Before those year (originaly) a big back rib.
I don not know if the size of the back rib would be defined by the HK of the jet.
So 500HK > big, 250HK > small.

 

Well, the problem is that I don't speak German and google translate can only take you that far

You are correct, I am puzzled by the sheer size of the rib, which is not like the one depicted in the patent drawing.
Do you know when they started to add this (big) rib? It must be previous to the 1951 patent.

 

Adrian,

The German patent bureau: depatisnet give also searchable text results. But even the German text is full of text errors so any automated translation is partly crap.
Other way is the European patent database espacenet. They give all the results in English.

.

Just cecked: but result are in translated German or should be translated German.

 

This large fin was already available at Petromax in the 1930s.In another forum I was able to see two Petromax 523s with white enameled hoods and that big fin on the carburator. One is NOS!
In myself had a Petromax from October 1950 with a big fin. I didn't see any more after 1950.I think the big fin was only ever installed on 500 HK lamps. But not all. The large fin points to the hand wheel.

Regards Reinhard

 

Thanks Reinhard. It makes sense that after Petromax registered the patent with the drawing describing the smaller fin, they kept making that design. So that would make the big fin specific to a period between 193? to 1951.

 

Well that indicates that the big outer fin had already been used before or during the War in a number of lamps. Only that I don't find many examples around my area. I've seen some on the Optimus and a few older Petromax clones.
I've not come across any E&G or Graetz patents for vaporizer with outer fins. The only one I've seen is the one by Fritz Graetz from the early 50s (small-ribbed).

 

Thanks for the translation Wim. It makes sense why they moved to the smaller fin design. Probably with the big rib more pre-heating is needed to reach operating temperature.

 

There was a later English-language version by Fritz Graetz, which was a US patent after the 1951 German one. I'd believe its pretty much similar.
Its a 1956 patent: US 2756579.

 

Thanks.

 

Well I did some quick searches on known names.
I guess the old patents from for ww2 simply didn't survive. Or where distroyed after the legal time was up.

As far as I know no patent was found for the Petromax, HASAG style of lanterns. As for the ones we know. lantern parts can be found and an early E&G, Hirschhorn Continental combined (!) patent for a lantern but no HASAG 5xx model as we know from the swiss army or a 500CP Petromax.

So a lot of history has still to be found and researched.

 

They may very well have been destroyed when Germany ceased to exist as a state and became occupied territory split in 4 occupation zones (1945-1949). These patents were of high commercial value and a lot of shady things happened in those days.
Plus let's not forget that in those days archives existed only in paper form, such a patent probably existed just in the archives of the Patent Bureau where it was registered. So if that office was bombed during the war...

 

No doubt about it. You are right. The lantern is war time, 1939-45. I checked my 2827B field lantern and the script on the label attached to the lantern identical to yours. So, that's solved!

 

You mean the metal plate on the lamp body?

 

Well it would be nice to know when they switched from the oval copper/black "number plate" to the aluminium flat plate.
You would think that all pre ww2 lanterns would have an E&G Berlin oval plate.

 

This lamp being November 1941 it is clear that the plate style changed before that. But this is almost 2 years after the start of WWII in Europe.

 

Yes, metal plate on the lamp. My lantern is dated June 1944.