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Carola player mechanism

PostPosted: Thu Mar 21, 2013 11:12 am
by benarth
Does anyone have any information on the Bluthner 'Carola' player mechanism?
I have just rescued a 1923 Gors &B Kallmann instrument from destruction,88 keys 1,37m high.
The mechanism seems to be a pretty standard installation apart from the small piggy back bellows attached to the
motor governor and pedal bellows,what is their purpose?
Benarth

Re: Carola player mechanism

PostPosted: Sun Apr 07, 2013 11:29 am
by Paddy
Gors and Kallmann pianos with the Bl├╝thner Carola mechanism are top quality instruments!

I've worked on several over the years. I think the parts you describe are to stop the motor staggering at sudden accents and loud playing: when the suction in the foot-pedal bellows increases, and thus the suciion on the tracker bar and the drag on the roll, the motor governor pneumatic receives extra down-pull which maintains the roll speed. There's usually some adjustment possible where the motor governor's piggy-back pneumatic's moving board applies its force.

Can you attach some pics and a simple tubing diagram?

Paddy

Re: Carola player mechanism

PostPosted: Wed Apr 10, 2013 2:15 pm
by benarth
Paddy,
Thanks for your reply.
I'm trying to add photos but don't at present know how to.
One piggy back bellows is at the base of the wind motor governor and the other at the base of the right hand control box above the two pedal bellows.
As you suggest the Bluthner Carola playing mechanism is a well built unit using very good quality parts and looks to be much better made than an Angelus player I used to have.
There is much work to do on the G&K as the previous owner had it stored in an outside workshop or garage so it has absorbed moisture leading to the action stiffening up and the key weight were previously removed presumably to make the keys drop when the unit is playing leading to the keys now not dropping away when in use as a normal piano.

Regards
Benarth

Re: Carola player mechanism

PostPosted: Wed Apr 10, 2013 4:04 pm
by djkprojects
Hello Benarth,

There is a "Upload Attachment" tab at the bottom of the page when creating or editing a post. I hope that helps.

Jack

Re: Carola player mechanism

PostPosted: Thu Apr 11, 2013 5:29 pm
by benarth
Photos now hopefully added. I was trying to use quick reply which does not allow attachments previously.
Various pipework previously used by past owners, I will be replacing after the piano action etc. attended to.
benarth

Re: Carola player mechanism

PostPosted: Thu Apr 11, 2013 7:51 pm
by Paddy
The two "piggy-back" pneumatics you show aren't what I supposed - they're most likely secondary valve operating pneumatics.

Are you sure the box on the right is the wind-motor governor? If so the pneumatic probably operates the valve to speed up the motor on fast forward and rewind, and the one on the left hand box may be the action cut-off (silencer).

If the left hand box is the bass expression regulator, and the right hand box the treble expression regualtor (and the wind-motor governor is elsewhere), the pneumatics either operate the accenting secondary valves, or action cut-off valves.

You need to find which tube makes each operate, and which pallet valve or tracker-bar hole they go to. Then we can probably deduce their function! :-)

Patrick

Re: Carola player mechanism

PostPosted: Sat Apr 13, 2013 4:54 pm
by benarth
You're right. Having had another look, the right hand box/bellows is not the wind motor governor(this is hidden behing this box) but is connected to the right hand end of the stack and one of the clear tubes dropping down into the box is connected to the silence button on the keyslip control panel.
The cloth covered tube on the left hand box/bellows drops down directly to the damper/sustain bellows and is connected to the left hand end of the stack. There is very limited movement allowed to the piggy back bellows(probably only a few mm's) but they are adjustable.
Benarth

Re: Carola player mechanism

PostPosted: Thu Apr 25, 2013 7:31 pm
by Paddy
Sorry - been away...

OK the piggy-back bellows could work the action cut-off valves, but look like they operate the big main accenting valves.

If the latter, there'll be a primary valve for each, maybe inside the regulator box, triggered by the long bass or treble Themodist port each end of the 88 note holes in the tracker bar.

Each pneumatic will probably be held closed by its valve during normal play and open momentarily when a "snakebite" passes over the Themodist port, though they could work in the opposite sense, and close when there's an accent. Either way their travel should be minimal, maybe 1/8 inch, so they work really fast, set just not to throttle big fortissimo accented chords.

The pedal suction is simply fed from the bass regulator box - very normal - and is cut off when the box cuts off on rewind or fast forward.

Hope this helps!

Patrick

Re: Carola player mechanism

PostPosted: Fri Apr 26, 2013 3:06 pm
by benarth
Patrick,

Thanks for that.
I presume then that this system is a bit of a step up on the standard accentuating system giving a faster and more subtle response to the snakebites on the roll, otherwise why install it.

Without boring anyone on the topic, having replaced various rubber tubes I now find that the wind motor now only runs at a speed directly related to the rate of pumping the pedals rather than as directed by the tempo lever ie the same speed whether set on fastest or lowest setting when in 'play' mode.

There is no direct linkage between the 'play/rewind' lever and the motor governor so I presume it must be activated by a vacuum fed valve within the box and there is tubing connected from the governor to the silence valve and on to the bass expression box/bellows. There is a spur on the 'play/rewind' linkage which opens a sprung valve on this tubing.

Is the vacuum to activate the cuttoff valve to divert vacuum to activate the stack bellows etc. likely to be generated in the motor governor or the bass expression box? the tempo control was previously working in relation to the control lever so I am presuming that the cuttoff valve in the motor governor is still in working order.

This system is not so straightforward as in my Weber/Steck uprights.

Benarth

Re: Carola player mechanism

PostPosted: Thu May 30, 2013 3:16 pm
by Paddy
Now that the PPG AGM and entertainments - very well received, thankfully! - I can give some more thought to your player.

Different manufacturers had to devise alternative methods of using the accenting perforations because of Aeolian's Themodist patents, but they basically all do the same thing: when a "snakebite" comes along in the bass or treble (or both), suction for that half of the stack is switched momentarily round a throttle slide or valve direct to the pedals, so a weaker or stronger stab of the toe will give an accent of the desired strength to the corresponding note(s). Accented notes do not accent themselves - you have to create accents using your feet.

In Pianolas two subduing levers worked by the left thumb operate bass and treble throttle slides. These are kept normally open by springs, and when an accented section of the roll comes along you close them judiciously to subdue the notes of the "accompaniment" over which you make accents. Thus you can play the accompaniment at any level from pp to ff, with accents only just discenible or very loud above. Some players have only a push button to subdue the accompaniment to lower level determined by the average foot suction level, with stabbed out accents above.

Pianolas (Aeolian) have suction-out primary Themodist (accenting) valves with adjustable brass top seats, and secondary pouches; Hupfelds have primary air-out mushroom primaries which open small pneumatics which move secondary disk valves. And there are many permutations used by other makers! I can't exactly recall what your Carola has, but we can probably deduce it.

The tempo is undoubtedly governed by a slide in the wind-motor governor, worked by the tempo lever. If the slide does not seat properly motor speed will be all over the place. The slide should begin to open its orifice at Tempo 0. This is the basic tempo setting. The spring on the governor pneumatic should be only strong enough to stop the motor slowing on loud and accented playing.

In most players, to make the roll go as fast as you pedal, the forward rewind lever works (apart from the spool-box gearing) a tempo bypass slide in the motor governorl. But in others it operates a pallet valve which opens a bypass in the motor governor. This is usually a secondary pouch or a pneumatic and slide worked by a primary valve fed with pedal suction via somewhere that is not turned off during silent rewind or fast forward.

Hope this helps!

Paddy