Author: DSatz
Date: 2018-03-16 16:53
Attachment: Side view of Mazzeo model Bundy (1).jpg (240k)
Attachment: Side view of Mazzeo model Bundy (2).jpg (202k)
For the original poster, let me see whether I can describe how it works in words and some still photographs that I have.
[1] The goal is to stop using the register key to produce throat Bb, but instead, always to produce it via the third RH trill key--without having to reach for that key for most passages. (You'd still use the trill key the normal way for any actual A to Bb trills.)
[2] For this purpose, that trill key is separated into two pieces: The pad cup and pad are on an "arm" that is sprung shut, while the remaining, long part of the trill key (the lever that you press to open the pad) is exactly the same as on a standard Boehm clarinet, including the spring arrangement. So now if you use that trill key, your own effort is still lifting the pad--but it's because the key that you're pressing is raising the separate "arm" that has the pad cup on it.
The whole rest of the mechanism is about the control over that pad--either causing it to open when it should, or preventing it from opening when it shouldn't.
[3] The LH thumb key isn't a "thumb ring"--it's solid and padded on Mazzeo clarinets, with its own spring to keep it normally open. But that feature (like the ringless bell) is a separate idea of Mazzeo's, and has nothing intrinsically to do with the Bb mechanism.
On any Boehm clarinet, the thumb ring connects to the first LH ring through a pair of connected levers; pressing the thumb ring lowers the first-finger LH ring. The Mazzeo mechanism exploits that mechanical linkage for a further purpose, which is to hold the pad for the throat Bb closed (via a cantilever) whenever the first LH ring is closed. This also means that the Bb pad can never open while the thumb key is closed.
One end of the cantilever rests on the pad cup for the Bb trill key, while the other rests on top of the pair of levers between the thumb key and the first LH ring. (There's an adjustment screw at the pad end of this cantilever, which is a critical adjustment for a Mazzeo clarinet.)
[4] The key that has the pad cup and pad for the Bb tone hole (can I call that the "Mazzeo key" just for the moment?) extends so that a small part of it is within reach of the second LH ring. A miniature, spring-loaded plunger is attached to the second LH ring key, and when the second LH ring is closed, that plunger puts pressure on the extended piece of the "Mazzeo key".
So overall, the mechanical logic works like this: If neither the LH thumb key nor the LH first finger are down, the cantilever isn't holding the Bb pad shut--so closing the second LH ring will cause the Bb pad to open. And of course, the normal bridge between the LH and RH joints closes the second LH ring whenever the RH rings are pressed.
So that's how you normally produce a throat Bb: with the LH A key plus any combination of RH rings and/or the second LH ring--and possibly other keys if that makes life easier for you (e.g. a scale across the break in any flat key).
But if either the LH thumb, the LH first ring or both are being pressed (i.e. for anything below open G), the Bb pad won't open because of the cantilever. The little spring-loaded plunger attached to the LH second ring will exert some pressure, but it simply compresses and doesn't do anything.
The same thing happens in the middle and upper registers--since the LH thumb key is always closed, the Bb pad can't open.
--The attached photos are from a Bundy Bb. The first one shows the spring-loaded plunger and the "Mazzeo key" more clearly, while the second one gives a better view of the padded thumb key and the cantilever.
--best regards
Post Edited (2018-03-16 16:57)
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The Clarinet BBoard
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