Why not pull-release?

[burt]

When I can get my scanner going, I'll do some sketches of a pull-release system.
It's a lot simpler than Allans all-pull diagram.
At its simplest, it is a single finger which is pulled by a rod (attached to a pedal or knee lever) until it touches the body, and can't move any further. The string is now tuned to the raise pitch at the keyhead.
Then the pedal/lever is released.
String tension pulls the finger back.
There is a tuning screw in the top of changer block (much like the screws on an all-pull split tuning changer) which controls the amount of backward movement of the finger, and this is where the open note is tuned.

[burt]

When a note is both raised and lowered, it becomes slightly more complex.
We'll assume that the string is lowered on a knee lever.
That lever is connected to the finger by a rod, and is held by a spring (against an adjustable stop) in the 'open' (un-activated) position.
The spring has to be just strong enough to overcome string tension.

The string is raised in the normal way, and tuned at the keyhead.
It is then released, the knee lever is activated, and the lowered note is tuned at the tuning screw in the changer block.

The knee lever is then released, and the aforementioned spring pulls it back to the open position.
The string is tuned to its open tuning using the adjustable knee lever stop.

[burt]

My pull-release Marlen in action

here

[burt]

My pull-release Denley
Here

[Allan]

Georg, thanks for the numbers, much appreciated.

Burt, your instruments sound wonderful, I really don't think it is possible to beat the tone of an older instrument. I don't know enough to comment on what can and can't be done as a result of the more simple type of changer mechanism. However, with that said, there seems to be little or no limitation as regards your playing. I am with you as far as building 'simple'. Thank you for your contribution to the thread - please continue with any other comments you may have, good valuable stuff.

I will probably start a new thread with my next post on this matter since I have moved away from the original subject. I am working on a new drawing and I'll post that for comment as soon as it is finished. (may be a while as it is more complicated than my last one.

Regards, Allan.....

[Pat Comeau]

Allan... that is a nice drawing but it is not a pull release changer ...and i don't think it would work properly because the raise would change when you'd pull the lowers and having tuning problem, it is easy to draw but not as easy to make it work accuratly and properly, on a pull release changer you have to have a screw for each finger for tuning just like the old Sho-Bud Maverick.

JMO..................Pat C.

[Allan]

Pat, you could well be right. As I said, it is just a concept drawing for discussion.

First off, the return-after-raise might well need a spring to help it to return to pitch and it does depend on the spring that I have on the drawing being strong enough to hold the lower lever(?) against the stop. The lower lever thus becomes the stop for the finger.

Also, I do have a 'next generation' drawing in the works at the moment.

Thank you for your comments, your experience as a builder is valuable.

Best regards, Allan.....
(Really like your YouTube stuff by the way)

[Allan]

I have started a new thread for the discussion on my 'discussion drawing'. 'Modified Pull Release...'

Sorry for stealing your thread Burt... I will go sit in the corner and say 4 copedents.

Allan.....

[Bill Ladd]

Ya know, now that I think about it and have re-read this thread, a pull release makes a lot of sense, Burt.

I got the changer parts I have with the guitar project I bought. They're factory-made parts from the old JCH guitars made by Jimmie Crawford and John Hughey. But there's no reason I have to use them.

Some major benefits I see are: a pull release setup will be a relative breeze to fabricate; it's the only PSG changer I've ever tuned or played on; and I'm going to use a standard E9/Emmons setup with no half-stops or anything out of the ordinary.

I mean, look at how basic this setup is:



Thanks for the reminder!

(Hope it's okay to link photos from SGF. If not, please let me know!)

[burt]

This is a sketch of the Marlen system