Improvements in Pneumatically Operated Organs.
Year: 1897

page_text: Date of Application, 26th Jan., 1897-Accepted, 22nd May, 1897
COMPLETE SPECIFICATION.
Improvements in Pneumatically Operated Organs.
I, MELVILLE CLARK, of 12th and Canal Streets in the City of Chicago,
County of Cook and State of Illinois, in the United States of America, Musical
Instrument Manufacturer, do hereby declare the nature of this invention, and.
in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
This invention relates to improvements in musical instruments in which the
sound-producing devices are caused to speak by means of so-called pneumatic
motors, and it consists in improvements in construction by which the pneumatic
is made much more sensitive than heretofore, that is, adapted to respond to less.
suction in the wind-chest, and specifically adapted to respond to less suction than is
necessary to cause the sound-producing devices themselves to speak. It is therefore
peculiarly adapted to reed or pipe instruments in which the suction or pressure of
air in the wind-chest, producing a current of air past or through the sound-producing
device is the means of making the latter speak, the same suction or pressure being
the means of operating the pneumatics.
:
J
In such instruments it is very important that a minimum quantity of air should
be used to operate the pneumatic devices, so that the work imposed upon the
bellows, in respect to the quantity of air which they shall pump, shall not be
excessively increased by the employment of the pneumatics beyond what would
be required for the sound-producing devices themselves. This consideration has:"
led to the employment of what may be termed "primary pneumatics,"-that. is,..
pneumatics which are primarily operated by the suction or pressure in the wind-'
chest, to operate the valves which control the communication with the wind-chest.'
of secondary pneumatics, such secondary pneumatics being the means of causing
the sound-producing devices to speak. This permits the use of a very small
primary pneumatic and of a secondary pneumatic of any necessary size to operate.
the sound-producing device, the quantity of air required to be pumped or drawn by
the bellows being determined by the size of the primary pneumatic, independently
of the size of the secondary or motor pneumatics. In such combination of primary
and motor pneumatics which have been commonly employed, the primary pneumatic
has been generally located within the wind-chest, so that its area might be subject
to the tension of air in the wind-chest. In organs or other musical instruments
operating by exhaust action in the wind-chest producing suction thereinto through
all passages communicating with the interior of such wind-chest, this construction
has been found to necessitate the employment of a spring whose function is to
collapse the primary' pneumatic, when the communication of that pneumatic with
the exterior air is closed by the controlling devices, such collapse being permitted
by a very restricted vent aperture with which the pneumatic is provided inside the
wind-chest. Obviously the inflation of the pneumatic by exterior air, when the
controlling devices admit such air, will be effected against the resistance of this.
spring, and the degree of rarefication necessary in the wind-chest in order to
produce the action of a pneumatic, must be such as to afford, by the difference
between the tension of the air within the bellows and that of the external air, at
least sufficient force to overcome the spring; and since the collapse of the bellows,
effected by the reaction of the spring, must be practically instantaneous in order
that the response of the reeds to the action shall be prompt and that the tones shall
L.

page_text: not overlap each other, and since the collapse must be effected by the discharge of
the air through a very small vent aperture in the primary pneumatic, the spring
requires considerable power in order thus to drive the air out through the small
orifice instantaneously. The result is that in practice, the minimum degree of
rarefication in the wind-chest which will cause the lightest reeds to speak, is
utterly insufficient to operate the pneumatics. For this reason, the finer
modulations of intensity of tone of organs operated pneumatically cannot be
produced except by muffling devices in the nature of swells. That is, the tension
in the wind-chest, being the least which is sufficient to operate the pneumatic
devices, is sufficient to produce a very loud tone from the reeds; and softer tones
are only producible by muffling such loud tones. Such organs, therefore, as
hitherto constructed, are not capable of fine gradations of tone, which, in an
organ operated from the key-board and by strictly mechanical connections from
the keys to the reed valves, are effected by the operator modifying the action
of the bellows to produce the expression desired from the reeds.
The advantage, therefore, of reducing the force necessary to operate the
pneumatics to and below the degree of force necessary as a minimum to cause
the reeds to speak, is that thereby it becomes possible to modulate the intensity
of the tone produced, and so to vary the expression at the will of the operator who
controls the bellows, and thereby to vary it in every degree, and not merely with
such step-by-step modifications as can be effected by means of swells. The means
which I employ for this result consist primarily in locating both the primary and
the motor pneumatics outside the wind-chest in such relation that springs in
connection with such pneumatics may be dispensed with.
In the drawings,
Fig. 1 is a vertical fore-and-aft section of a portion of the wind-chest and
pneumatic action of an organ having my improvements.
Fig. 2 is a similar section of like parts of an organ having duplex arrangement
of motor pneumatics, reed chambers and valves cöoperating with each primary
pneumatic.
Fig. 3 is a similar vertical fore-and-aft section of a pneumatic action resembling
that seen in Fig. 2, but having the primary pneumatic placed horizontally instead
of vertically.
.
Fig. 4 is a detail section showing a modification of the primary pneumatic.
Figs. 5, 6 and 7 are detail sections representing a modification of the primary
pneumatic in respect to its connections with the wind-chest, said figures corresponding
respectively to Figs. 1, 2 and 3.
Figs. 8 and 9 are magnified detail sections of the valves operated by the primary
pneumatics corresponding to two forms of such valves shown respectively in Figs. 1,
2 and 3 and in Figs. 5, 6 and 7.
A is the wind-chest. In Fig. 1 I have shown one reed block thereon having
two reed chambers controlled by a single valve B. This valve is operated by a
motor pneumatic C, mounted upon the forward vertical side of the wind-chest, and
operating the reed-valve by means of a bell-crank lever C, and suitable flexible
connections from its arms respectively to the pneumatic C and the reed valve B.
I do not limit myself in any respect to the specific situation of the motor
pneumatic or of the reed valve. D is the primary pneumatic. In the form
shown in Fig. 1, it is also mounted on the forward vertical side of the wind-
chest and is in the form of a bellows whose movable side is suspended at its
upper end and oscillated between the fixed side and the forward side of the
wind-chest. The primary pneumatic communicates with the wind-chest through
a duct d, which is restricted at its mouth opening into the wind-chest by a disk d²,
through which a very small puncture is made. The primary pneumatic also
communicates with the outer air through a duct represented by the tube D¹.
This tube may extend to a tracker range where the access of air will be con-
trolled by the travelling perforated strip in a manner well understood, and it
may be controlled in any other manner at will; and in some of the forms of

page_text: my invention herein shown, the primary pneumatic has double communication
with the outer air, one communication being controlled by a perforated strip at
a tracker range, and the other being controlled by a valve operated by a key
of the manual. The motor pneumatic communicates by means of the duct C
formed in the forward wall of the wind-chest, both with the interior of the
wind-chest at c¹ and with the exterior air at clo. Valves E and F, mounted on
the same stem e control these two openings respectively, the valve F being formed
on or secured to the oscillating side of the bellows which constitutes the primary
pneumatic, so that the movemeut of that side of the pneumatic in one direction
or the other seats one valve of the other, and puts the motor pneumatic in
communication either with the interior of the wind-chest or with the exterior
air. Said oscillating wall of the primary pneumatic, pendant as described, hangs,
normally, that is, when free from the influence of the wind-chest or any
extraneous force, with the valve F in contact with its seat at the orifice c¹.
It will be understood that when the air in the wind-chest is rarefied by the
pumping action of the bellows, the primary pneumatic being in communication
with the wind-chest through the duct d, is virtually a continuation of the wind-
chest, and is subject to the same rarefication of its contents, and is therefore
collapsed, and its oscillating side is held away from the side of the wind-chest,
carrying the valve F off its seat and seating the valve E, thus giving the motor
pneumatic communication with the exterior air and cutting off its communication
with the wind-chest; this condition of affairs continues so long as the com-
munication of the primary pneumatic with the exterior air through the duct DI
is closed; but when said duct is uncovered at its outer end, as by the regis-
tration of an aperture of the travelling perforated paper strip with the mouth
of the duct at the tracker range, atmospheric pressure being admitted freely
to the pneumatic and the exhaust through the punctured disk d being very
restricted, the primary pneumatic becomes inflated normally and the valve. F
comes to its seat, the valve E being opened, thus cutting off communication of
the motor pneumatic with the outer air and establishing communication of the
same with the wind-chest, and causing collapse of the motor pneumatic under
exterior atmospheric pressure; the connections from the motor pneumatic being
such that the movement of its oscillating wall involved in such collapse, causes
the sound-producing devices to speak, as, in the case of a reed organ, by lifting
the reed valve B. This condition continues so long as the mouth of the duct
which admits atmospheric air to the primary pneumatic remains uncovered, but
ceases, the parts returning to the original positions,-whenever that duct is
closed since then the suction from the wind-chest collapses the primary pneumatic.
In this construction it will be observed that all the valves and both the
pneumatics operate without springs; and furthermore, that the oscillating parts
of the pneumatics being pendulous, the operation involves the minimum resistance,
even by the weight of the moving parts. In practice, the bellows walls of the
primary pneumatic,-which must be practically air-tight, because these pneumatics
are, as stated, practically a continuation of the wind-chest, have a slight elasticity,
and this elasticity is taken advantage of to ensure the. normal seating of the
valve F against the side of the wind-chest, since, without care in this respect,
the slightest stiffness and elasticity of material employed for this purpose might
sometimes operate to hold the valve off its seat, even contrary to the action of
gravity by which it will be normally seated; but this precaution is only taken
because it is not practicable to construct these small pneumatics so that invariably
the bellows walls, at their normal condition, shall tend to hold the valve F. in
the same position in which it is held by gravity, that is, just barely resting
at the outer surface of the wall of the wind-chest. By thus dispensing with
all devices exerting pressure to seat the valves, or collapse the pneumatics,
I produce an instrument in which the pneumatics will act upon the very slightest
suggestion of rarefication in the wind-chest, and long before the rarefication has
reached a degree sufficient to make the reeds speak. It thus becomes possible

page_text: to moderate the intensity of the tone of the instrument precisely as if the reeds
were being manipulated by hand, or by strictly mechanical connections with the
manual, the lightest tone of which the reeds are capable being producible
when the reed valves are operated by pneumatics, and all variations from
the lightest to the most intense being effected by varying the operation of the
bellows.
In Fig. 2, I have shown my invention applied in a reed organ in which each
primary pneumatic controls the action of two motor pneumatics, such motor
pneumatics operating the valves of independent sets of reeds, the motor
pneumatics being placed horizontally instead of vertically, and overhanging the
reed-valves which they respectively operate. The reed valves B B, operating
over reed chambers which are mounted upon the front and rear sides of the
wind-chest A, are respectively operated by horizontal motor pneumatics C C,
placed heel to heel overhanging the reed valves respectively. These motor
pneumatics are mounted upon the under side of a board A', upon the upper side
of which is a supplement A of the wind-chest, which is supported above the
wind-chest A, proper, by hollow standards affording communication through
ports A30, from the wind-chest proper to said wind-chest supplement A2. The
primary pneumatic D is mounted upon the forward side of the wind-chest
supplement A2 in precisely the same manner as in Fig. 1. The duct d, restricted
by the perforated disk d¹, being the means of air communication from the wind-
chest to the interior of the pneumatic, D' being the duct leading to the tracker
range. The duct C, which leads from the interior of the motor pneumatics,
extends from the cross-passage C1 up through the board A' on the forward side
of the wind-chest supplement A³ into the cross-duct which, at the port c¹, opens
into the wind-chest supplement, and at the port c¹º, opens to the exterior air,
said ports being closed by the valves E and F respectively, operated as in Fig. 1,
-by attachment to the oscillating side of a primary pneumatic D. It will be
understood, therefore, that the operation is precisely the same in this structure
as that shown in Fig. 1.
In Fig. 3, I have shown the primary pneumatic placed horizontally instead of
vertically, and having its moving side overhanging the port co, so that it operates
more positively by gravity to seat the valve F than in the construction in which it
is pendulous. I have shown this arrangement and position of the primary
pneumatic in connection with the duplex construction and arrangement of motor
pneumatics which is shown in Fig. 2. For the purpose of such an arrangement of
the pneumatics, the wind-chest supplement Ab is supported by the hollow
standards A3 in such manner as to leave its under side, instead of its forward side,
exposed for the purpose of mounting thereon the primary pneumatic D, and in this
construction the fixed wall of the primary pneumatic is mounted directly against
the under wall of the wind-chest supplement and protrudes beyond the wind-chest
supplement at the rear to afford convenient means of connecting with the primary
pneumatic the duct D¹ which leads from the tracker range. The passage C,
having the cross-passage C for the two motor pneumatics, in this construction
leads from the wind-chest proper, A, up through the board A" on the under side
of which the motor pneumatics are mounted. The valves E and F operated by
the moving side,--which is the under side,-of the pneumatic, control the ports c¹
and co, as in the construction shown in the other figures.
In all of these forms, provision may be made for operating the instrument by a
inanual instead of by means of the perforated sheet travelling over the tracker
range, and in all the forms this may be done in either one of two ways,-to-wit,
either by mechanical connections from the keys of the manual to the reed valves B,
making a mechanical action entirely independent of the pneumatic action, or by
providing the primary pneumatic with a communication with the exterior air in
addition to that which it obtains through the pipe which leads to the tracker range,
and controlling such additional communication by a valve operated by means of
connection with a manual key. The latter means is illustrated in the drawings.

page_text: In the form shown in Fig. 1, the second air communication for the primary
pneumatic is afforded by means of the duct g in the board which forms the side of
the wind-chest, such duct leading into the duet d. In the form shown in Fig. 2,
the same function is performed by the duct g formed in the board G, mounted on
top of the board A', and having the fixed side of the primary pneumatic mounted
against its rear edge, the duct g extending on through the fixed wall and thus
leading into the pneumatic chamber. In the form shown in Fig. 3, the same
function is performed by the durt 7, which is made in the board A, on which the
primary pneumatic is supported, said duct continuing up through the block D³
which forms the heel of the primary pneumatic. In each case, the outer end of the
duct which thus affords the second outer air connection of a primary pneumatic is
controlled by a valve H on a lever H', suitably fulcrumed at its rear end upon any
convenient fixed part, and having at its forward end suitable means for mechanical
connection with a manual key, as the link H2. The specific means by whic
mechanical connection from the manual key either to the valve H or to the reel
valve B is made, constitutes no part of the present invention, and I have
therefore not illustrated any means for making the connection with the valve B,
since any obvious modes and means for this purpose will occur to those familiar
with the art.
In the principal figures I have shown the primary pneumatic as of the bellows
form, but I do not limit myself to this form. Other well-known forms of
pneumatics may be employed, such, for example, as the form shown in Fig. 4, in
which a diaphragm from behind or under which a duct leads to the wind-chest, is
substituted for the oscillating side-bellows. This form has one advantage over
a bellows form, in that it is more easily made air-tight, as it is essential the primary
pneumatic should be, when it is exterior to the wind-chest. In the diaphragm
form of pneumatic, the valve F mounted on the diaphragm will be held normally,
that is, by virtue of its structure and the action of gravity upon it without the
influence of the wind-chest,-in contact with its seat by the diaphragin at its
normal position. The easiest action is obtained by making the diaphragm so
that normally, when free from the influence of the win 1-chest, it bulges slightly
outward, as seen in Fig. 4, and does not fluctuate far enough to reverse the
direction of its curvature or fullness, but is stopped by the seating of the valve E
before it has moved far enough to have a tendency to bulge the other way.
This outward bulging tendency of the diaphragm thus normally sets the valve,
with the same effect as, in the pendulous form, the valve is seated by gravity
without sensible pressure upon its seat. The same result as to normal seating of
the valve by the diaphragm at its normal position would be attained if the
diaphragm were normally straight and sufficiently elastic to be depressed by the
suction experienced from the wind-chest, but this would require tensile elasticity,
and the diaphragm so constructed cannot be made so delicately sensitive to slight
rarefication in the wind-chest as a diaphragm applied with a little fullness, causing
it to bulge toward the valve seat.
By the term "primary pneumatic," as employed in the above specifications' and
in my claims, 1 meau a pneumatic whose action, immediately caused by the
difference between the tension of the air within the wind-chest and that of the
external air, is the initial action in a train which comprises a secondary pneumatic
or pneumatics, whose ultimate action causes the sound-producing devices to speak.
This term thus used, therefore, excludes pneumatics which mechanically operate
the means for causing the sound-producing devices to speak and which are included
in the term "motor pneumatics," as used in this specification.
The importance of these distinctions will be understood when it is remembere.l
that in constructions in which a pneumatic is caused or permitted to operare in a
musical instrument for any purpose by admitting atmospheric pressure to it (as iu
all constructions in which a perforated sheet or equivalent device is the means
employed, there is, unavoidably, a constant waste of air while the pneumatic is
kept thus exposed to the atmospheric pressure, that is to say, while the sound-

page_text: producing device is being caused to speak. The pneumatic which operates the
sound-producing device, as by operating the reed valve in the case of a reed organ,
termed the motor pneumatic, must have sufficient area to afford the necessary
power to operate the valve or equivalent device; and if such motor pneumatic is
also the primary pneumatic (whose action is caused by admitting atmospheric
pressure to it) in order that such pneumatic should act promptly both in opening
and closing the reed valve, or performing whatever function depends upon its
action for commencing and terminating the speaking of the sound-producing device,
the vent or orifice through which the air is wasted or drawn in in the action of the
pneumatic which continues while the exterior air communication is open, must be
proportioned properly to the size of the pneumatic, and must therefore be larger in
proportion as the pneumatic is larger. If the primary pneumatic, therefore, be
made to serve also as the motor pneumatic, the waste of air will be very great and
the duty thus imposed upon the bellows is liable to become excessive, necessitating
either very large or very rapidly acting pumping devices. These considerations
have led to the almost universal practice of interposing between the pneumatic
which is operated by a perforated strip or other means for admitting external air
through such pneumatic, and the means for immediately operating the sound-
producing devices, a secondary pneumatic whose action, either inflation or collapse,
shall be caused by changing its communication from the external air to the wind-
chest or vice versa, so that each action (inflation and collapse) shall consume only
the quantity of air which the pneumatic requires for inflation or expels in
collapse.
My present invention has to do strictly with structures in which there is a
primary pneumatic in the sense above defined and a secondary pneumatic in the.
sense above indicated, since only when both are employed for the purpose for which
the employment of both is useful does the occasion arise for discriminating
between the interior and exterior location of such pneumatics with respect to the
wind-chest.
said
In Figs. 5, 6 and 7 I have shown a modification of the primary pneumatic in
respect to the connection thereof with the wind-chest, the modification being
designed for the purpose, primarily, of accomplishing, in respect to the initial
seating of the valve F, the same thing that is accomplished by the mounting of the
pneumatic so that by the action of gravity alone said valve normally reaches its seat.
The same thing also is accomplished by the construction of the pneumatic shown.
in Fig. 4, in which the bulging of the diaphragm tends to hold the valve normally
at its seat. In the form shown in these figures, there is one passage leading
through the wall of the wind-chest in place of two passages shown in the principal
figures. In place of the duct & shown in the principal figures, I employ, in the form
shown in Figs. 5, 6 and 7, a duct a through the stem of the valves E and F,
steni indicated by the letter ea, being thereby rendered tubular. The disk d¹ is
then applied over the inner side of the valve E, through which the duct in the
stem e opens, as in the other construction it is applied over the inner end of the
duct d. This change in structure of the primary pneumatic connection, when
applied to the form shown in Fig. 3, dispenses entirely with the supplemental
chamber A and the standards A leading thereto. The action of the modified
device is that when the communication of the primary pneumatic with the outer air
is opened, admitting atmospheric pressure within the pneumatic and causing it to
be drawn in through the pneumatic into the wind-chest through the puncture in
the disk d', the inrush of air through the tubular stem e and against the under side
of the punctured disk d', tends to pull the valve stem inward to unseat the valve E
and seat the valve F, precisely as in the form shown in Fig. 1, for example, and
the pendulous position of the moving side of the pneumatic under the action of
gravity tends to cause the valve F to move toward the seat as the moving side
of the pneumatic swings pendulous-like when released from the suction which holds
the pneumatic collapsed. In all the forms shown, the valve being exposed to
atmospheric pressure at the outer side and to diminished pressure at the inner side,

page_text: tends to move inward as soon as the force exerted upon it by the primary pneumatic
reases by the admission of atmospheric air into the latter. In the form shown in
Figs. 5, 6 and 7, an additional influence of the same nature operates through the
tubular stem e upon so much of the area of the disk d' as covers the duct in the
stem d that is, the area equal to that of the duct less that of the puncture
in the disk d. This influence, tending to move the valves in the same manner
as they tend to move by gravity, is independent of the influence first above mentioned
due to the frictional action of the air as it moves inward through the duct in the.
stem da
Since the primary pneumatics are constantly, during the operation of the
instrument, exposed to suction, being in communication interior with the wind-
chest and being exterior exposed to atmospheric-pressure, some waste is liable to
occur through the tissues or diaphragms of such pneumatics, and the employment
of the tubular stem for the valves E and F, as illustrated in Figs. 5, 6 and 7,
affords an opportunity to reduce this possibility of waste at least one-half by
providing within the primary pneumatic a cushion or seat d³, secured to the inner
wall of the fixed side of the pneumatic in which the inner end of the tubular
stem d shall seat when the pneumatic is collapsed, thus closing the communication
between the interior of the pneumatic and the wind-chest after the partial vacuum
neressary to cause the collapse of the pneumatic has been produced therein. This
partial vacuum will be gradually diminished by the leakage until the pressure of
the end of the tube upon the seat relaxes sufficiently to permit the air to be drawn
past the seat into the wind-chest by the suction operating from the latter, thus
restoring the vacuum again, but never permitting sufficient movement of the
valves E and F to operate to reverse the connection of the motor pneumatic and
cause it to operate. The loss by leakage is diminished by this means, because
the partial vacuum in the pneumatic which causes such leakage is a steadily
diminishing force until it becomes so far diminished as to permit its restoration
in the manner described. Such restoration occurs instantly when the pressure.
on the cushion permits the air to pass, so that the average vacuum is therefore
about one-half the maximum, and the aggregate leakage is therefore reduced about.
one-half.
Since the motion of the stem of the valves E and F, when attached to an
oscillating or hinged bellows-side, is not directly longitudinal with respect to the
stem, the two valves require to have their seating surfaces not exactly parallel,.
in order that they may each in turn seat properly at the ports which they
respectively control. To avoid the necessity of the very accurate adjustment
which will be necessary to insure perfect seating, I prefer to make the valve loose
on its stem so that it may adjust itself to its seat when it strikes it. This feature
cannot be recognized by the eye in the actual construction, nor in drawings of
actual size, but I have shown in Figs. 9 and 10 magnified details from which it
may be understood. When the solid stem, such as shown in Figs. 1, 2 and 3 is
employed, such stem extends loosely through the valve E, and is provided with a
head e to stop the valve, and adapted to pull it onto its seat at whatever slight
angle thereto it may strike it. In the tubular form shown in Figs. 6, 7 and 8, the
tubular stem is flanged at the end for the same purpose and with the same effect,
the disk being made fast to the outer surface of the flange represented by d¹.
In all the forms, the necessary adjustments of the valves E and F to each other in
respect to their distance apart may be made by screwing the stem more or less
through the valve F, and, if necessary, into or through the side of the bellows to
which the valve F is attached.
Having now particularly described and ascertained the nature of this said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. In a pneumatic organ, in combination with an exhaust wind-chest, a primary
nneumatic and a motor.nneumatic both exterior to the wind-chest and communicating t

page_text: therewith for exhausting and with the outer air for venting said pneumatics;
the valves which control the exhaust and vent ports of the motor pneumatic being
connected to and operated by the primary pneumatic to exhaust the motor
pneumatic when the primary pneumatic is vented, and to vent said motor pneumatic
when the primary pneumatic is exhausted; connections from the motor pneumatic
by which the sound-producing devices are caused to speak when said motor
pneumatic is collapsed, and suitable means for uncovering the vent of the primary
pneumatic; the vent valve of the motor pneumatic being at its seat normally
under the influence of gravity when free from any influence proceeding from the
wind-chest.
2. In a pneumatic organ, in combination with an exhaust wind-chest, a primary
pneumatic and a motor pneumatic both exterior to the wind-chest and communi-
cating therewith for exhausting and with the outer air for venting said pneumatics;
the valves which control the exhaust and vent ports of the motor pneumatic being
connected to and operated by the primary pneumatic to exhaust the motor
pneumatic when the primary pneumatic is vented, and to vent said motor pneumatic
when the primary pneumatic is exhausted; connections from the motor pneumatic
by which the sound-producing devices are caused to speak when said motor
pneumatic is collapsed, and suitable means for uncovering the vent of the primary
pneumatic; the vent valve of the motor pneumatic and its connection to the
primary pneumatic being exterior to the wind-chest, said primary pneumatic being
adapted normally under the influence of gravity and when free from any influence
proceeding from the wind-chest to stand expanded and in position to hold said valve
at its seat.
3. In a pneumatic organ, in combination with an exbaust wind-chest, a primary
pneumatic and a motor pneumatic both exterior to the wind-chest and communi-
cating therewith for exhausting and with the outer air for venting said pneumatics;
the valves which control the exhaust and vent ports of the motor pneumatic being
connected to and operated by the primary pneumatic to exhaust the motor
pneumatic when the primary pneumatic is vented, and to vent said motor
pneumatic when the primary pneumatic is exhausted; connections from the motor
pneumatic by which the sound producing devices are caused to speak when said
motor pneumatic is collapsed, and suitable means for uncovering the vent of the
primary pneumatic; said primary pneumatic being adapted normally when vented
and thereby relieved from the influence of the wind-chest, to expand by the action
of gravity on its moving wall to the extent necessary to hold the exhaust valve
of the motor pneumatic off its seat and the vent valve of said pneumatic at its seat.
4. In a pneumatic organ, in combination with an exhaust wind-chest, a primary
pneumatic and a motor pneumatic both exterior to the wind-chest and communi-
cating therewith for exhausting and with the outer air for venting said pneumatics;
the valves which control the exhaust and, vent ports of the motor pneumatic
being connected to and operated by the primary pneumatic to exhaust the motor
pneumatic when the primary pneumatic is vented, and to vent said motor pneumatic
when the primary pneumatic is exhausted; connections from the motor pneumatic
by which the sound-producing devices are caused to speak when said motor
pneumatic is collapsed, and suitable means for uncovering the vent of the primary
pneumatic; the exhaust communication of the primary pneumatic with the wind-
chest being restricted relatively to the vent of said primary pneumatic, and the
vent valve of the motor pneumatic being adapted normally, under the influence
of gravity, when the primary pneumatic is vented, to stand at its seat.
5. In a pneumatic organ, in combination with an exhaust wind-chest, a primary
pneumatic and a motor pneumatic both exterior to the wind-chest and communi-
cating therewith for exhausting and with the outer air for venting said pneumatics;
the valves which control the exhaust and vent ports of the motor pneumatic
being connected to and operated by the primary pneumatic to exhaust the motor
pneumatic when the primary pneumatic is vented, and to vent said motor pneumatic
when the primary pneumatic is exhausted; connections from the motor pneumatic

page_text: by which the sound producing devices are caused to speak when said motor
pneumatic is collapsed, and suitable means for uncovering the vent of the primary
pneumatic; the moving wall of the primary pneumatic being pendulous and at
normal position under the action of gravity, when said pneumatic is vented and'
freed from the influence of the wind-chest, adapted to hold the motor pneumatic
vent valve at its seat.
6. In combination with the wind-chest, a primary pneumatic and a motor
pneumatic whose communication with the wind-chest is controlled by the primary
pneumatic, the valve which effects such control having its stem tubular and
constituting the communicating passage between the wind-chest and the primary-
pneumatic.
8. In combination with the wind-chest, the primary pneumatic exterior thereto.
and a motor pneumatic whose communication is controlled by the primary
pneumatic; the valve which effects such control having its stem tubular and
constituting a communicating duct between the wind-chest and the primary
pneumatic.
9. In combination with the wind-chest, a primary pneumatic exterior thereto;:
a motor pneumatic also exterior thereto; valves which control the communication
of the motor pneumatic with the wind-chest and with the external air being
operated by the primary pneumatic and being mounted on a common stem, said
stem being tubular and constituting the communication between the wind-chest.
and the primary pneumatic.
10. In combination with the wind-chest, and an exterior primary pneumatic,.
a tube which is attached to the fluctuating wall of the pneumatic and which extends
into the wind-chest and constitutes the means of communication between the wind-.
chest and the pneumatic; and a pallet or valve within the pneumatic adapted to be
seated over the inner port of said tube when the pneumatic is collapsed.
11. In combination with the wind-chest, a primary pneumatic exterior thereto.
and a motor pneumatic whose communication with the wind-chest and with the
outer air is controlled by the primary pneumatic; the valve which effects such..
control having its stem tubular and constituting the communicating duct between
the wind-chest and the pneumatic; and a pallet or seat within the primary
pneumatic on which the inner port of said duct seats when the pneumatic is.
collapsed.
343 OT
MELVILLE CLARK..
By Herbert Haddan & Co.,
18 Buckingham Street, Strand, London, W.C.,.
Agents to Applicant.