Jump to content
Mander Organ Builders Forum

Pallet Design


John Robinson
 Share

Recommended Posts

Peelingpallet.jpg

 

I should be very grateful for any comments on this idea for an improved design of pallet in which the conventional wooden pallet is replaced by a strip of spring steel with a felt backing to seal the opening to the channel when closed. A refinement to this opening is a 'V'-shaped extension at the end adjacent to the tracker.

 

Its operation is as follows:

 

1. The pallet is closed and the spring holds the pallet firmly against the opening.

 

2. Slight pressure on the key pulls down end of pallet, which begins to bend. At this stage, the pallet is just beginning to uncover the 'V' section of the opening, allowing a small flow of wind to pass into the channel.

 

3. Further movement of key causes the pallet to bend further, admitting a greater wind flow.

 

4. Key fully depressed: pallet fully open.

 

(Release of the key reverses this sequence.)

 

Because the pallet 'peels' away from the windway the force required to open the pallet, and the 'pluck', are lighter.

 

Due to the 'V'-shape of the front of the opening, and the fact that the pallet gradually curves away from the opening, it should be possible to more easily control the attack and release of the note.

 

As this design of pallet is probably of a lower mass than a conventional one, it is likely to possess lower inertia, permitting quicker response and repetition.

 

Note that only the front quarter or so of the pallet (the end nearest to the tracker) needs to be flexible: the remainder need not be so.

 

To summarise, the innovations I have in mind are:

 

(i) a spring steel pallet, being wholly or partially flexible;

(ii) a 'V'-section to the proximal end of the opening to the channel.

 

Unfortunately, I do not have the facilities to try this out in practice but, intuitively, I imagine that it could work successfully. I should be most grateful for any comments or criticisms, especially from those familiar with organ construction or repair.

 

I hope this works: I have never tried to post images on here before!

 

John

Link to comment
Share on other sites

I apologise if this sounds terribly like I'm an expert, which I'm not, but what I've learned from working on a few 'heavy' actions to make them into light ones goes like this.

 

In a conventional set-up the function of the pallet spring is not to shut the pallet, but to help the wind hold it closed and compensate for weight, inertia and friction in the action. This is especially true where there is no felt on the face of the pallet, but only leather; where felt and leather are combined the spring may have a small squeezing role.

 

The actual mass and inertia of a wooden pallet is small when compared with the weight of action, roller arms and all the rest of it which hang off the back, and which do not enjoy the same opposing force (wind) as the pallets themselves. A spring which is doing any more than compensate for the weight hanging off the pallet, enabling the note to snap shut quickly on release, is inefficiently set up and all those inefficiencies are transferred straight to the finger and nowhere else. One of the many things which irritate me is when you take all the springs out of a soundboard to find them each of differing strengths, with some more than twice as strong as others.

 

Sorry to sound negative, but my gut reaction would be that having a non-rigid control over the wind would lead to sponginess and cause every note to 'creep' on, especially in the bass, for several reasons -

 

1) Because the design of the pallet and groove are effectively making it easier for the note to come on, springing will have to be much stronger than would normally be required to keep the note off. This is fine when the note is off, but becomes inefficient when trying to hold the note on or make it repeat quickly.

 

2) Taking away the natural point of pluck will make the touch feel indistinct in any case.

 

3) Because some of the movement of the action would then become diagonal (as it would have to in order to trace the curve of the springing section) you would need a much greater touch depth than normal to achieve sufficient opening (which is usually achieved more or less immediately after breaking the point of pluck).

 

Where I think your ideas COULD work would be as a new form of relief pallet, as Hill and others used to do; on a larger soundboard, your springy pallets could be used to open a bleed hole on the main pallet, which would open very quickly behind having had some of its excess pluck taken away. There would also be a good application for large pneumatic/electropneumatic basses, e.g. 32' basses which when given sufficient wind to speak well often go past the point at which the action is able to cope, and where superb repetition is not really a requirement.

Link to comment
Share on other sites

Many thanks for the feedback, David.

 

I should have realised that all methods of lightening the touch would have been fully explored by now!

 

My intention was not to remove all traces of any 'pluck', as I realise how important this is, but that by varying the degree of flexibility of the spring-steel pallet and also the shape of the 'V'-section of the opening it might be possible to reduce the weight of touch at the expense of some of the 'pluck'.

 

I suppose my idea is just an extension of the 'pallet-in-two-parts' (sorry, I don't know the correct name for this!), whereby initially just a short section at the end of the pallet pulls down, equalising pressure on both sides and allowing the rest of the pallet to be opened more easily. Presumably, this system works effectively.

 

Moreover, I realise that in many situations a 'traditional' pallet works perfectly well. I was thinking more of the bottom end of the compass or, perhaps, with higher wind pressures.

 

John

Link to comment
Share on other sites

Many thanks for the feedback, David.

 

 

 

I suppose my idea is just an extension of the 'pallet-in-two-parts' (sorry, I don't know the correct name for this!), whereby initially just a short section at the end of the pallet pulls down, equalising pressure on both sides and allowing the rest of the pallet to be opened more easily.

 

John

 

Usually called split pallets.

 

I refered elsewhere to an HNB idea of using variable numbers of pallet magnets, dependng on how many stops were in use, which caused tuning problems because of no consistency of wind supply to the pipes. I suspect that your idea may have the same effect. Be fun to try it though - perhaps on an old instrument that is due to be taken down?

 

Regards to all

 

John

Link to comment
Share on other sites

Usually called split pallets.

 

I refered elsewhere to an HNB idea of using variable numbers of pallet magnets, dependng on how many stops were in use, which caused tuning problems because of no consistency of wind supply to the pipes. I suspect that your idea may have the same effect. Be fun to try it though - perhaps on an old instrument that is due to be taken down?

 

Regards to all

 

John

 

Well, it's not so different from the Hill relief pallets I've seen, which were very useful in the bass; independently sprung so that if the pallet could open easily enough without them, it would, but if there was a lot of weight there then it would be broken by the relief pallet opening first. In the treble, a complete nightmare because notes half-speak the instant you touch the key and it's nearly impossible to play cleanly. Luckily they can be screwed tight to the main pallet.

Link to comment
Share on other sites

Usually called split pallets.

 

I refered elsewhere to an HNB idea of using variable numbers of pallet magnets, dependng on how many stops were in use, which caused tuning problems because of no consistency of wind supply to the pipes. I suspect that your idea may have the same effect. Be fun to try it though - perhaps on an old instrument that is due to be taken down?

 

Regards to all

 

John

 

Yes, indeed. I should love to experiment in this way - given the necessary facilities.

 

Anyone got an old organ (or a bit of one - I only need a small windchest, a blower and a few representative pipes!) they don't want?

 

John

Link to comment
Share on other sites

This is one of those mind-teasing exercises, where the theory of physics meets age-old craft, and I have to admit at the outset, that I have no idea how it would work, if it would work and whether if it could and would, whether it would work satisfactorily. (Does this sentence make sense?)

 

The thing which must hit me about John's idea was the co-existence of progressive thinking on the one hand, but retrograde thinking on the other.

 

For instance, if one is using spring-steel (maybe phosphor-bronze), why does the design assume that some sort of end-pivot is desirable, as in traditional pallet design?

 

If designed right, it would not require a separate pallet spring at all; being held in place at one end by a clamp or groove (with a 90 degree bend in the pallet material and a locating groove and retaining plate). The spring would be under-tension at all times; open or closed, but when closed, it would be almost de-tensioned. So it wouldn’t be any more powerful than the usual pallet spring. Your relief V-shape (or other suitable bleed arrangement) could be in the centre of the spring-pallet; the spring itself free to slide at one end in a guide-channel; thus allowing the spring to move and bend naturally along its working “curve”. This also has the added advantage of entirely vertical motion at the pull; thus eliminating one of David’s concerns about diagonal movement.

 

Of course, pluck is a something which would require test-bed development, because the last thing you want is a springy action without feel or initial resistance.

 

The one “problem” which I cannot immediately think of a way of solving, is the business of a centre-drawn leaf-spring having a natural sliding-motion, which over a period of time, would damage any sort of flexible sealing; including leather and felt. Of course, with carefully machined spring-pallets and a properly engineered mating-face, it would seal enough when new to prevent any ciphers. My concern is what happens with age, if the spring loses tension or starts to distort in some way.

 

I suspect that this is one of those wonderful exercises in lateral-thinking, which ends up back where it started with the original design still being the best!

 

I do like the idea of spring-steel and engineering however, because this fits in well with my modular organ-construction ideas, where a whole gallery of spring-steel pallets could be a separate module bolted or screwed to the underside of a wind-chest.

 

Lastly, I was intrigued by David’s observation of pallet spring rates found in organs. I had no idea there could be so much variance. We live and learn!

 

MM

Link to comment
Share on other sites

For instance, if one is using spring-steel (maybe phosphor-bronze), why does the design assume that some sort of end-pivot is desirable, as in traditional pallet design?

 

If designed right, it would not require a separate pallet spring at all; being held in place at one end by a clamp or groove (with a 90 degree bend in the pallet material and a locating groove and retaining plate). The spring would be under-tension at all times; open or closed, but when closed, it would be almost de-tensioned. So it wouldn’t be any more powerful than the usual pallet spring. Your relief V-shape (or other suitable bleed arrangement) could be in the centre of the spring-pallet; the spring itself free to slide at one end in a guide-channel; thus allowing the spring to move and bend naturally along its working “curve”. This also has the added advantage of entirely vertical motion at the pull; thus eliminating one of David’s concerns about diagonal movement.

 

MM

 

No, my design does not, in fact, assume an end-pivot. The spring pallet is fixed at the distal end and 'peels' away from the opening. I must apologise for the lack of quality in the diagram which may not make this clear (try clicking on the diagram and enlarging - it works with Firefox, anyway!).

 

The addition of a separate pallet spring was an afterthought. Initially, I thought that the pallet would possess enough 'spring' to close itself firmly - assisted by the pressure of wind, of course. However, I added a separate spring just to make sure! As I mentioned earlier, such things would have to be ascertained by experimentation, and I do not have the means to do that. Also, the shape and position of the 'V'-shaped cut-out would have to be determined empirically. The inclusion of a 'V'-shaped cut-out, incidentally, was not to ease the opening of the pallet, but to provide greater control of attack and release.

 

As for the diagonal movement of the proximal end of the pallet, I did not think this important as there could be a flexible connection between tracker and pallet.

 

I am grateful for your interest in this proposal, and your comments. Whether it would work or not, I found it an interesting hypothetical exercise!

 

John

Link to comment
Share on other sites

Lastly, I was intrigued by David’s observation of pallet spring rates found in organs. I had no idea there could be so much variance. We live and learn!

 

MM

 

This is why, from time to time, I have been guilty of banging on at great length about poorly set up tracker actions, particularly on older jobs attended to by people whose main training and experience has perhaps been in EP and pneumatic instruments. 'Opening the spring up a bit' is a notorious cure-all for a range of maladies whose actual cause lies elsewhere, for instance friction at the key/backfall/rollerboard. After a few years of this sort of treatment it's quite common to pull all the springs out of a soundboard and find some of them twice as strong as others. It's no wonder some organs get a bad reputation and find people calling for their replacement or updating with something allegedly better (or at least less 'heavy, cumbersome and unmusical'). It can be quite a salutory exercise to switch the wind off, then find a weight (a couple of fishing weights maybe) which are just sufficient to move and hold down a note, then try the same weight on all the other keys. Sure, the bass should be a *bit* heavier, and the sharps being shorter will require a weeny bit more, but not much in either case.

Link to comment
Share on other sites

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
 Share

×
×
  • Create New...