Clock spring to coil spring conversion

[P@rick]

Hi all,

I'd like to share my clock spring to coil spring conversion to you. The story will be more in pictures than words, but I think you don't mind at all

I bought me this Alexander (see thread: viewtopic.php?f=2&t=29655" target="_blank" target="_blank" target="_blank)

The valves were running ok(ish) and two needed at least some new springs. There was also some play/margin on the axel of the clock valves. I decided to rebuild the valve block, starting with converting the clock springs to coil springs.

The story went like this:

The Tuba to start with.


After removing 10 screws.


The guts.


Drilling and sawing.


Desoldering.


Anyone for spare parts?


After providing a technician (with the right equipment) my design on paper this is what I got back. It is fitted perfectly for a 4mm silversteel axle/shaft (not shown in this picture).


Mounted and ready to be used with standard (miraphone) coil springs.


All of them together on the 4mm silversteel axle/shaft.


The next step was to convert the S-linkage to a miniball (ball-joint) system, but the valves are running so smooth that I will have a go on the tuba for a while before taking this step.

Regards,
Patrick

[tubamlb]

M&M Tuba has the compleat key boards with linkage, ball links. fits miras and most 4 rotor tubas , just bolt on

$225.00 There web site http://WWW.TUBAMM.COM" target="_blank not all the parts they sell are listed but give them a call and they can help you

[Dan Schultz]

I did something similar but a bit simpler on a Zeiss with messy linkage a while back:

[P@rick]

I did something similar but a bit simpler on a Zeiss with messy linkage a while back...

Your project is what inspired me to do mine

I liked your idea, but the problem with me is that I'm not only a Quality Engineer during working hours

The improvements I needed/wanted were:
- Better fit around the axle.
- Didn't want to unwrap the coil spring to make it fit between the branches. So I made the branches (II) smaller and made "I" as small as possible.

- I wanted it to be lighter than the original clock work.

The S-linkage to rod-end conversion is on hold because the valves run very smooth/light/fast without clatter. I did this conversion on a one of my previous Tubas. I used stainless steel rod-ends with bronze wrapping/bearing:


If I'm going to do the conversion on the Alexander, I will use smaller rod-ends next time to save more weight. As you van see I bend the rods to have a perfect rotary movement/force on the valve. If you keep the rods straight you will ad a diagonal force that will ad a linear movement on the axle of the valve. The valve will wear down faster and result in clatter of the valve in its casing.

Regards,
Patrick

[iiipopes]

Nice. All the different variations on how to do it in various ways. Nice.

[Rick Denney]

As you van see I bend the rods to have a perfect rotary movement/force on the valve. If you keep the rods straight you will ad a diagonal force that will ad a linear movement on the axle of the valve. The valve will wear down faster and result in clatter of the valve in its casing.

If you do a free-body diagram and plot the forces on the ball ends as vectors, I think you'll find that the forces end up the same no matter what. A ball end really should be positioned so that the center of the ball contact area is on the axis of applied force, and that force is applied diagonally no matter how you have the ball end positioned. If you want to center the force on the ball, you should mount the ball on the diagonal. But as long as the ball end shell doesn't rub on the shank of the ball, the forces are similar enough no matter what orientation not to worry about it. That's why you use ball ends.

Rick "who bends the levers only to avoid interferences" Denney

[P@rick]

As you van see I bend the rods to have a perfect rotary movement/force on the valve. If you keep the rods straight you will ad a diagonal force that will ad a linear movement on the axle of the valve. The valve will wear down faster and result in clatter of the valve in its casing.

If you do a free-body diagram and plot the forces on the ball ends as vectors, I think you'll find that the forces end up the same no matter what. A ball end really should be positioned so that the center of the ball contact area is on the axis of applied force, and that force is applied diagonally no matter how you have the ball end positioned. If you want to center the force on the ball, you should mount the ball on the diagonal. But as long as the ball end shell doesn't rub on the shank of the ball, the forces are similar enough no matter what orientation not to worry about it. That's why you use ball ends.

Rick "who bends the levers only to avoid interferences" Denney

It sounds convincing, but are you sure? It's just that somebody told me differently...i don't know for sure myself so you confuse me

[Dan Schultz]

As you van see I bend the rods to have a perfect rotary movement/force on the valve. If you keep the rods straight you will ad a diagonal force that will ad a linear movement on the axle of the valve. The valve will wear down faster and result in clatter of the valve in its casing.

If you do a free-body diagram and plot the forces on the ball ends as vectors, I think you'll find that the forces end up the same no matter what. A ball end really should be positioned so that the center of the ball contact area is on the axis of applied force, and that force is applied diagonally no matter how you have the ball end positioned. If you want to center the force on the ball, you should mount the ball on the diagonal. But as long as the ball end shell doesn't rub on the shank of the ball, the forces are similar enough no matter what orientation not to worry about it. That's why you use ball ends.

Rick "who bends the levers only to avoid interferences" Denney

It sounds convincing, but are you sure? It's just that somebody told me differently...i don't know for sure myself so you confuse me

He's sure. I was going to comment but figured Rick was lurking and would post about the force vectors. I spent 35 years in machine design and Rick is 100% correct. The only reason one would have for bending the links so everything is in-line would be to eliminate clearance problems.

BTW... very nice job. Very neat and exact-looking. I might have spent more time on the Zeiss job but my customer only wanted to spend $50! (Just kidding, Jim.... just in case you are watching this thread! Break a leg at the parade Saturday night. I'm REALLY enjoying Maine!)

[P@rick]

Patrick, how do you like the horn so far?

Quotes from my wife:
"Stop humping that horn..."
"That horn gets more attention than me..."
"...a bunch of brass as a competition...that does it… "

Does this tell enough ?

P.s. I'm still married...it's just that my wife has a good sense of humor.