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Bob Essex Bronze Member
Joined: 26 Jun 2006 Posts: 5 Location: Napton-on-the-Hill
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Posted: Tue Jul 11, 2006 10:44 am Post subject: GLOCKENSPIEL MECHANISM |
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Hi There all Alley-Cats.
I have a question for those with experience of the wonderful glockenspiels to be seen on large Gaviolis, Marenghis etc.
I am aware of the way the glock beaters operate by exhausting the bellows-motors, causing the beaters to hit the bars. But could someone please explain the method by which all of the beaters slowly rise before the glock starts to play, then slowly descend to rest on the bars again afterwards.
I have been trying to puzzle this one out. No doubt the glock has its own windchest which is pressurised from a ketframe signal, and I can see how this could inflate the motors. But how does it do it so slowly?
The beaters operate quickly to the release of pressure in the motors, but then recover quickly also. So an airway restriction doesn't seem the likely method of getting the slow release when the glock has finished playing.
This question arises because I am planning to build a glockenspiel for the front of King Solomon and would love to give it a similar action. It is a real crowd-puller having moving parts in view.
Any help would be appreciated.
Bob Essex |
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George Houghton Site Admin
Joined: 21 Jun 2006 Posts: 162 Location: Cheshire
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Posted: Tue Jul 11, 2006 11:10 am Post subject: |
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Hi Bob.
I too am interested in the answer to this question.
I have just accepted the slow rising action of the beaters as being the norm and have not thought about the way it is achieved.
I hope some one with the knowhow can enlighten us.
Regards
George |
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Dave Stubbs Site Admin
Joined: 19 Jun 2006 Posts: 174 Location: Manchester, UK (Tel: 0161 794 5558/ Mob: 07985 437940)
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Posted: Tue Jul 11, 2006 2:22 pm Post subject: Hi Bob! |
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Hi Bob.
...Nothing to do with Glock mechanisms, but I thought that I would mention that I have added a picture of King Solomon in the Organs Photo Gallery (taken at Victoria Park 2005)!
Regards, Dave |
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Allan Guest Bronze Member
Joined: 04 Jul 2006 Posts: 11 Location: Lancashire
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Posted: Tue Jul 11, 2006 11:24 pm Post subject: |
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Hi there Bob,
I think I can be of help, as I have just fitted a glock register to Graham Atkinson's Marenghi. The glock needs to be made whereby the motors are inflated all the time, then on selecting a note the motors wind supply is cut off and exhausted, thus allowing it to collapse. Thats the first part!!
And thats what we had already.
You need to make a latching relay box, this will enable a small register slot to latch and declanche dpending where you put the glock in the music.
The out put from this then goes to a second relay. This will give the main wind supply to the glock and will supply it with all the wind that it needs.
This box takes great care when making as you need enoigh wind to lift the beaters, which are spring loaded, but also you don't want too much spring tension on the beaters because when you turn the glock off the beaters will fall quickly to the bars and cause them to play!
Peter Griffiths can explain it better if you can't understand me, he's better at wording things then me and he saw the two units just mentioned as he made all the springs for me when I went to see him! |
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Bob Essex Bronze Member
Joined: 26 Jun 2006 Posts: 5 Location: Napton-on-the-Hill
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Posted: Wed Jul 12, 2006 9:06 pm Post subject: |
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Thanks Alan for your help. I understood all about the register box etc.
The question I am really asking is - how do all the beaters rise so slowly, and also fall back again slowly?
Their normal action is to play rapidly. The beaters fall quickly to sound the bells as their motors exhaust, due to the springs. But they also rise again quickly as they are re- pressurised from the organ wind.
I am guessing there must be a very small ventil hole which pressurises the glock chest slowly, but how then do the motors reinflate quickly when they are playing? Perhaps the small hole opens wider after the motors are fully inflated, and closes again to a small hole when the relay box turns the glock off. This guess seems reasonable but I am curious to know how it is done.
Bob |
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Allan Guest Bronze Member
Joined: 04 Jul 2006 Posts: 11 Location: Lancashire
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Posted: Wed Jul 12, 2006 9:36 pm Post subject: |
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BOB,
A glock motor should inflate quickly, it shouldn't take a while to inflate because if the register is only selected just when its needed then the first notes used isn't quite right, because the bars are not being hit from full height. So you want that beater up straight away. The way that it falls slowly is so so simple. You just stop the wind going to the glock chest. Thats it!
Its like blowing up a bouncy castle, then turning the blower off, it will deflate slowly through small gaps in the stiching etc. If you untie the exaust hole at the back then it rapidly goes down!
The weight of the springs slowly brings the beaters down, and because they are only coming down slowly the beaters shouldn't (unless your beaters are touching the bars at rest) hit the bars.
Also this method will probably only work properly on a picollo section here really you are only playing one note at a time. If its on the melody section and you have a cord of 5 notes, then you are letting all the wind out of your bouncy castle fast and it will fall!!! |
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Peter Griffiths Bronze Member
Joined: 29 Jun 2006 Posts: 5 Location: Cumbria UK
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Posted: Thu Jul 13, 2006 6:18 pm Post subject: |
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Hi there Bob
Allan is quite correct in what he says. The reasoning behind the workings is this.
When the box is first given wind from its ventil, there are 17 or more fairly largish pneumatic motors to inflate all at once. This takes quite a considerable 'Puff' of wind. If the valve that lets the air into the chest is reasonably restricted - here it depends on the size of the motors and the wind pressure - then the hammers will rise fairly fast, but not with a huge CLUNK. On an average, a 19 mm hole opening will do OK.
When the register is cancelled, then the ventil shuts, and due to the slow leakage in the leather pouches and valves the action box will slowly de-pressurise, thus the hammers will go down very slowly. This can be quickened slightly by using a 2mm escape hole to free air in the ventil. Do not make the ventil to open a huge air escape hole when it switches off.
Don't forget that when the glock is playing, the air escaping to operate the hammers is working via a different valve. Each hammer has its own change over valve to stop the pressurised air going into the motor, and allowing it to escape to free air.
Two or three glock motors operating at once will still inflate fast, as the main inlet restriction is set to take into account the full set of motors inflating.
I tend to work this restriction by threading the ventil push rod, and putting on a large leather button. This can be adjusted to alter the amount the ventil valve opens.
If you have a small number of glock bars, and small pneumatic motors, then this will not be as easy to set up. In fact the inlet restriction may give problems to the glock playing. It will still switch off reasonably slowly though.
I hope this helps you - though a favourite saying comes to mind
Bullshit Baffles Brains!
Cheers
Peter Griffiths |
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George Houghton Site Admin
Joined: 21 Jun 2006 Posts: 162 Location: Cheshire
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Posted: Fri Jul 14, 2006 4:55 pm Post subject: |
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Thanks Alan and Peter.
For the explanation It is so simple when explained by someone who knows.
But oh so mysterious to the unenlightened.
Regards
George |
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Bob Essex Bronze Member
Joined: 26 Jun 2006 Posts: 5 Location: Napton-on-the-Hill
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Posted: Mon Jul 17, 2006 4:27 pm Post subject: |
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Thanks Allan and Peter for the explanation.
I want to try and build a glockenspiel using the same degree of showmanship, just to create something to watch and marvel at, on the front of the organ.
Best regards
Bob |
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