Appliances for Muting Pianofortes and Varying the Touch for Practising Purposes.
Year: 1897

page_text: Date of Application, 2nd Nov., 1897-Accepted, 29th Jan., 1898
COMPLETE SPECIFICATION.
Appliances for Muting Pianofortes and Varying the Touch for
Practising Purposes.
We, ALFRED RUDOLPH SPOERL, Piano Tuner, of 15, Bleecker Street, Brooklyn, in
the County of Kings and State of New York, and WILLIAM LOUIS GEISLER, Musician,
of Jerusalem Avenue, Hampstead, in the County of Queens aud State of New York,
United States of America, do hereby declare the nature of our invention, and
in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
The invention relates to mute attachments for ordinary pianos; and its object is.
to provide a new and improved touch and technic stop for pianos, and arranged
to enable a performer to render the piano mute and to permit finger exercise with
any degree of resistance to the keys.
The invention consists in a novel construction of the mute attachment; further in
a novel construction of the resistance for the keys, and lastly in a novel connection
of the mute attachment with the resistance, all as hereinafter described and
claimed.
Reference is to be had to the accompanying drawings forming a part of this
specification, in which similar characters of reference indicate corresponding parts
in all the figures.
Figure is a cross section of the improvement, showing the hammers locked out
of action;
Figure 2 is a similar view of the same, showing the resistance out of action and the
hammers released;
Figure 3 is an enlarged sectional plan view of the improvement, on the line 3-3
of Figure 1;
Figure 4 is a cross section of the same, on the the line 4-4 of Figure 3;
Figure 5 is a like view of part of the same, showing the resistance out of engage-
ment with the keys;
Figure 6 is an enlarged sectional side elevation of the resistance, on the line 6-6
of Figure 7;
Figure 7 is a sectional front elevation of the same, on the line 7-7 of Figure 6;
Figure 8 is a side elevation of the same, with parts in a different position and parts
broken out;
Figure 9 is a sectional side elevation of the same, on the line 9-9 of Figure 7 ;
and
Figure 10 is a similar view of the same on the line 10-10 of Figure 3.
The upright piano shown in the drawings, is provided with the usual casing A and
keys B connected at their rear ends by links C with jack levers C¹ carrying a jack C²
engaging the hammers D for throwing the latter upon the strings E, to sound the
same in the usual manner. The hammers D normally rest on a hammer rail D',
and the jack levers C¹ rest at their forward ends on a rail F, preferably made in the
form of a felt covered roller, journaled in suitable bearings in arms F" pivoted at F2
to a rail of the action, as is plainly shown in Figures 1, 2 and 4.
The arms F' rest on vertically-disposed rods or posts F³, fitted to slide in suitable
bearings in the casing or frame A, and each of the said rods F³ carries a forwardly-
TD 071

page_text: extending foot F, resting at its free end on an arm F5, secured to a laterally-extending
shaft G, mounted to turn in suitable bearings formed in a bracket A' attached to the
casing A.
The shaft G extends a suitable distance above the rear ends of the keys B, and one
end of said shaft is provided with a downwardly-extending arm G¹, connected by a
link G2 with a lever G³, fulcrumed on the keyboard frame, and provided with a
handle G under the control of the operator, to permit the latter to swing the
lever G transversely and turn the shaft G, to cause the feet F to be raised or
lowered by the action of the arms F5. When the feet F are raised, on throwing the
lever G³ forward in the direction of the arrow a¹ (see Figure 4) the rods F³ are
lifted and the arms F¹ carrying the rail F are moved upward, to swing the jack
levers Cupwardly, thereby lifting the links C out of engagement with the rear ends
of the keys B, and causing the jacks C2 to swing the hammers D into an inter-
mediate position, as indicated in Figure 1. When the several parts are in this
position, the keys B when pressed do not act on the links C, and consequently the
hammers are not actuated and the piano is rendered mute.
When the lever G³ is moved in the inverse direction of the arrow a¹, the feet F*
move downward as the arms F5 swing in a downward direction, and consequently the
rods F, arms F¹ and rail F move downward, to permit the jack levers C¹ to swing
in a like direction and allow the hammers D to fall back to their normal resting
position on the rail D¹, as illustrated in Figure 2. The links C now are again in the
path of the rear ends of the keys B, and when the latter are played, the hammers
are actuated and the strings are sounded in the usual manner.
When the lever G³ is moved forward into the position shown in Figures 3 and 4
and the piano is rendered mute as described, a resistance H (Figure 9) is thrown in
to engagement with the keys B, and when the lever G³ is moved in the inverse
direction of the arrow a¹, the said resistance H is thrown out of engagement with the
keys at the time the hammers D move into an active position, as described above and
shown in Figure 2. The resistance H is actuated from the shaft G, and the latter is
provided for this purpose with gear wheels G5 in mesh with segments I¹ formed on
the frame I carrying the resistance H. The frame I is mounted to turn loosely on
a longitudinally extending shaft J, journaled in the brackets A¹, previously mentioned.
The frame I is formed with guide plates 12 and 13 one above the other, and carrying
rods K, adapted to rest on the tops of the keys B between their pivots and the rear
ends, as is plainly indicated in the drawings, it being understood that each key is
adapted to be engaged by a corresponding rod K. The downward movement of each
rod K is limited by projections or pins K', adapted to be seated on the upper guide
plate I, as is plainly shown in Figure 7. The top of each rod K is engaged by a
spring L, extending transversely, and secured at one end to a rail I' forming part of
the frame I. On the free end of each spring L is secured a block L', normally
resting on a plate N supported in the frame I, the block being also adapted to engage
with its top a second plate N', vertically adjustable in guideways 1° forming part of the
frame I. Suitable screws N2 engage the plate N', to raise or lower the same and
permit the spring L to swing more or less according to the resistance desired to be
given to the corresponding key B.
It is understood that when a key is pressed at the time the resistance H is in active
position, the upward swinging of the rear end of the key lifts the corresponding
rod K, and the latter moves in contact with the spring L, to swing the same upward
until the block L' strikes against the under side of the plate N¹, to limit the further
swinging of the spring L in this upward direction. More or less tension can be given
to the spring L by means of a laterally-extending bar O extending over the springs L,
and secured at its ends to arms 0¹, secured by screws 02 to plates P fitted to slide
transversely in suitable guideways I', formed in the sides of the frame I. See
Figures 6, 7 and 9.
Each of the plates P is formed at its under side with a rack P¹ in mesh with a gear
wheel P secured on the shaft J, and on one outer end of this shaft J is secured a
gear wheel Qin mesh with a rack Q¹, fitted to slide transversely in suitable bearings

page_text: formed on the frame A.
The rack Q is formed with a forwardly-extending arm Q²,
pivotally connected with a lever Q3, fulcrumed on the keyboard frame, and formed
with a handle Q adapted to be taken hold of by the operator. The lever Q³ is
provided with a pointer R, adapted to indicate on a scale R¹, fixed on the keyboard
frame at one side of the last treble key, as plainly indicated in Figure 3.
Thus it will be seen that when the operator swings the handle Q4 of the lever
rearwardly, the gear wheel Q is turned by the rack Q1 in the direction of the arrow b¹
(see Figure 6) whereby the shaft J is turned in the same direction, and the gear
wheels P² are rotated to shift the racks P¹ and consequently the plates P backward,
to move the bar O over the springs L toward their free ends and increase the tension
of the said springs, to give some resistance to the rods K when the latter are moved
upward upon pressing the corresponding key B. The bar O can be adjusted up or
down by moving its arms O¹ correspondingly upon loosening the set screws 0², so that
the said bar O does not engage the springs L, until some time after the rods K
have started on their upward movement upon pressing the keys B.
Now it will be seen that by the arrangement described, any desired resistance can
be given to the rods K to regulate the touch of the operator pressing the keys.
Furthermore the sliding motion of the said rods can be limited if desired by
adjusting the plate N¹ correspondingly in the guideways I®.
The rail 1 is preferably made vertically adjustable on the sides of the frame I,
as indicated in Figure 10, so as to adjust the springs L relative to the upper ends
of the rods K, and the springs L are adjusted vertically relative to the rods K by set
screws I screwing into the bottom of the rail 1 against strips L³ of leather, felt or
like material and bearing against the under side of the springs between their fastened
end and the rods K as plainly shown in Figures 5 and 6, the strips L³ serving to
render the springs noiseless.
When the lever G³ is in the position shown in Figures 3 and 4, the hammers D
are in an inactive position and the resistance H is thrown into an active position,
owing to the turning of the shaft G as previously described, the said shaft by its
gear wheels G5 imparting a swinging motion to the frame I since the said gear
wheels engage the segments I¹. When the lever G³ is shifted rearwardly to permit
the hammers to fall back into their former resting position, a swinging motion is
thereby given to the frame I, to cause the latter to assume the position shown in
Figures 2 and 5, whereby the rods K are moved out of engagement with the keys B,
and the latter when pressed do not touch the said rods, but actuate the hammers in
the usual manner. The resistance H is now out of action, and the hammers are in
action, and when the lever G³ is in the position shown in Figure 4, the hammers are
thrown out of action and the resistance is thrown into an active position, as shown
in Figure 4.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
1. A device of the class described, comprising a swinging frame carrying spring-
pressed rods adapted to engage the keys, means for swinging the frame toward or
from the keys, a rail for the jack levers, and a lifting mechanism for said rail
operated by the swinging of the frame, substantially as described.
2. A device of the class described, comprising a swinging frame, elastic parts
carried by the said frame and adapted to engage the keys and to form a resistance
therefor, means for swinging the frame toward or from the keys, a rail for the jack
levers, and a lifting mechanism for said rail operated by the swinging of the frame,
substantially as described.
3. A device of the class described, provided with a resistance comprising rods
fitted to slide, and adapted to rest on the keys, and springs pressing on the said
rods, substantially as shown and described.
4. A device of the class described, provided with a resistance comprising rods
fitted to slide and adapted to rest on the keys, springs pressing on the said rods, and

page_text: means, substantially as described, for increasing, or decreasing the tension of the
said springs, as set forth.
5. A device of the class described, provided with a resistance comprising rods fitted
to slide and adapted to rest on the keys, springs pressing on the said rods, and means,
substantially as described, for limiting the swinging motion of the said springs, as
set forth.
6. A device of the class described, provided with a resistance comprising rods fitted
to slide and adapted to rest on the keys, and springs pressing on the said rods, each
of the said springs being provided at its free end with a block or weight adapted to
swing between two plates, one of which is adjustable, substantially as shown and
described.
7. A device of the class described, provided with a resistance, comprising a frame
mounted to swing, and under the control of the operator, rods fitted to slide in the
said frame and adapted to rest on the keys, and springs held on the said frame and
engaging the said rods, each of the springs being provided with a block or weight at
its free end, substantially as shown and described.
8. A device of the class described, provided with a resistance, comprising a frame
mounted to swing, and under the control of the operator, rods fitted to slide in the
said frame and adapted to rest on the keys, springs held on the said frame and
engaging the said rods, each of the springs being provided with a block or weight at
its free end, and a bar adjustably held over the said springs for regulating the tension
of the springs, substantially as shown and described.
9. A device of the class described, provided with a resistance, comprising a frame
mounted to swing, and under the control of the operator, rods fitted to slide in the
said frame and adapted to rest on the keys, springs held on the said frame and
engaging the said rods, each of the springs being provided with a block or weight at
its free end, a bar adjustably held over said springs for regulating the tension of the
springs, and means substantially as described, for adjusting said bar over the said
springs, as set forth.
10. A device of the class described, provided with a resistance comprising a frame,
rods fitted to slide in the said frame, springs pressing on the said rods, a bar adjust-
ably held over the said springs, means for shifting the said bar, and a device for
indicating the position of the bar relatively to the springs, as set forth.
11. A device of the class described, provided with a rock shaft under the control
of the operator, and carrying arms, posts fitted to slide vertically and provided with
feet engaging with the said arms, binged arms connected with the said posts, and a
rail carried by the said hinged arms and adapted to engage jack levers, substantially
as shown and described.
12. A device of the class described, comprising rods fitted to move vertically, a
shaft carrying a projection or cam operatively connected to said rods for raising or
lowering them, a rail arranged to move vertically with said rods and engaging that
part of the action which is connected directly to the hammers, whereby said part of
the action may be removed out of the path of the keys or of that part of the action
which is permanently connected to the keys, and a mute attachment mounted to
swing on said shaft in unison with said cam, substantially as described.
Dated this 2nd day of November 1897.
A. M. & WM. CLARK,
Chartered Patent Agents, 53, Chancery Lane, London.