I still have and use early Conshelf regs and I also have a brand new one and a couple of inbetweeners. The mechanical bits are essentially unchanged. The exterior design evolved but the basic design of the mechanisms remains unchanged. Now are parts interchangeable all the way back, no, well, kinda, no, maybe, yes, sorta. Now, the design, as I mentioned of the housings changed, exhaust valves got larger, the slip on tee replaced the one with two screws, the metal plenum came along at the same time. The first stage innards did not change particularly in design but the housing evolved to accommodate a screw on yoke, multiple LP and HP ports etc and the strength of the housing/yoke was bulked up to handle the 3,000 psi standard.
We can argue as to what came first and who said what and did what. I have no doubt that USD incorporated design changes and KM engineering into their products including the Conshelf after purchasing the company or whatever that particular arrangement was. But fact is, I have a 1966 Royal Aqua Master that uses the same parts in the first stage as my newest and last Conshelf and fact is the second stage demand lever, downstream seat and basic layout of the Conshelf was cemented before the KM venture and actually goes back to the early 60s Calypso. Does all this matter, not really, just something to talk about.
I interchange levers, seats, diaphragms and first stage components, pretty sure, to keep the older ones going. I like the older versions because they have a lower profile and this is useful for a secondary/pony/octopus regulator.
The newest KM might breath like a jet engine, but the rubber cover is a long term concern, I would prefer the traditional all metal KMs.
Recently a certain publication challenged my company with a design claim that were not the originator and that we bought another company to obtain the design. True, we bought that other company, in the late 50s, because they had engineered some improvements and patents being long expired the only way we could stop them was to buy them and in fact we needed their engineering team. Well, a simplification. However, the publication insisted, at which point, the vault of secrets was accessed and the napkin (yes) with the basic design that was patented with pencil drawn mechanical layout of the components and dated and signed 1927, was laid before the doubters. I am not sure if the big boss asked if they wanted carbon dating! At which point, they tucked tail and ran.
Companies buy other companies or merge etc. all the time, to eliminate competition, or to obtain market share, or to obtain engineering or proprietary data or improvements or new designs or just because they complement one another and are a good fit to share resources in a competitive marketplace.
N
, etc. That is just a few of the items that I remember.
