U.S. patent number 3,845,683 [Application Number 05/396,057] was granted by the patent office on 1974-11-05 for keyboard for electronic musical instrument.
This patent grant is currently assigned to Pratt-Read Corporation. Invention is credited to Alfred H. Lehmann.
United States Patent |
3,845,683 |
Lehmann |
November 5, 1974 |
KEYBOARD FOR ELECTRONIC MUSICAL INSTRUMENT
Abstract
A keyboard for a musical instrment includes a frame with keys
pivotally mounted thereon, and a switch structure secured to the
frame including individual switch contacts actuated by the keys. A
circuit board is mounted on the frame and extends in a plane
parallel to the keys, with a second right angle circuit board
mounted thereon having resilient switch conductors extending
generally parallel to the keys. An actuator for each key includes
an insulator with openings through which the conductors extend.
Fixed contacts in the form of bus bars are positoned to be
selectively engaged by the resilient conductors to complete
circuits from the circuit boards. A stop structure is provided for
the keys including a resilient stop engaged when the keys are moved
to the normal playing position. This movement of the key causes
engagement of at least some of the switch conductors. The keys can
be moved further to compress the resilient stop to provide a second
touch action. Additional circuits may be established by the further
movement of the keys. The stop structure can be in the form of a
flat upwardly extending resilient strip which is engaged by a
plurality of keys, and can have slits providing a separate portion
for each key. Alternatively, a resilient tubular member can be
provided for each key, to form the stop.
Inventors: |
Lehmann; Alfred H. (Clemson,
SC) |
Assignee: |
Pratt-Read Corporation
(Ivoryton, CT)
|
Family
ID: |
26972648 |
Appl.
No.: |
05/396,057 |
Filed: |
September 10, 1973 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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301895 |
Oct 30, 1972 |
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Current U.S.
Class: |
84/719; 84/DIG.7;
84/433; 84/687; 984/345 |
Current CPC
Class: |
G10H
1/344 (20130101); G10H 2220/281 (20130101); Y10S
84/07 (20130101) |
Current International
Class: |
G10H
1/34 (20060101); G10h 001/00 () |
Field of
Search: |
;84/1.01,423,424,430,432-436,439-441,1.17,DIG.7
;29/624,625,626 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Tomsky; Stephen J.
Assistant Examiner: Weldon; U.
Attorney, Agent or Firm: Mueller, Aichele & Ptak
Parent Case Text
This is a continuation, of application Ser. No. 301,895, filed Oct.
30, 1972 now abandoned.
Claims
I claim:
1. In a keyboard for a musical instrument including a frame
structure and a plurality of elongated keys pivotally mounted on
said frame structure, the combination including:
a first circuit board secured to the frame structure and extending
generally parallel to the plane of the keys, said first circuit
board having first and second ends and including circuit components
and conductors thereon,
a second circuit board secured to said first circuit board adjacent
said first end thereof and extending at substantially a right angle
thereto, said second circuit board including circuit components
thereon and conductors thereon connected to said conductors on said
first circuit board,
elongated resilient conductor means individually associated with
the keys supported on said second circuit board and extending
therefrom in the direction from said first end to said second end
of said first circuit board and generally parallel to the keys and
having a portion extending beyond said second end of said first
circuit board, said resilient conductor means being connected to
said conductors on said second circuit board,
actuator means individually secured to the keys and extending
perpendicular therefrom, said actuator means being coupled to said
extending portion of said resilient conductor means for moving the
same in response to movement of the keys, and
fixed contact means secured to the frame structure and positioned
to be selectively engaged by said resilient conductor means in
accordance with the movement of said actuator means, whereby
actuation of one of the keys provides a connection from a circuit
on said first circuit board through said second circuit board and
said resilient conductor means to said fixed contact means.
2. The structure of claim 1 further including resilient stop means
positioned to be engaged by a key upon movement of the key to a
first position, said stop means being responsive to a predetermined
pressure on the key to permit movement thereof through said first
position to a second position.
3. The structure of claim 2 wherein said conductor means includes
first and second elongated conductors associated with at least one
key, and first and second fixed contacts positioned to be engaged
by said first and second conductors, respectively, with said first
conductor engaging said first contact in response to movement of
the key to said first position, and said second conductor engaging
said second contact in response to movement of the key to said
second position.
4. In a keyboard structure for an electrical muscial instrument
including a frame structure, a plurality of keys pivotally mounted
on the frame structure, and electric switch means coupled to the
keys for actuation thereby, the combination including;
stop means on each of said keys,
a resilient member positioned to be engaged by said stop means upon
movement of a key to a first position to actuate the switch means
coupled thereto, and
means for supporting said resilient member on the frame
structure,
said resilient member having a wall extending generally in the
direction of movement of said stop means and providing resistance
to further movement of the key upon engagement by the key, said
wall being formed of material which flexes to permit further
movement of the key through said first position to a second
position in response to a predetermined pressure applied thereto by
the key.
5. The structure of claim 4 wherein said resilient member is formed
by a flat strip of resilient material extending generally
perpendicular to the keys, and adapted to be engaged by said stop
portions of a plurality of keys.
6. The structure of claim 5 wherein said flat strip of material has
slits cut therein to form individual wall portions engaged by said
stop portions of individual keys.
7. The structure of claim 4 wherein said resilient member is a
tubular member having a shape to be compressed.
8. The structure of claim 7 wherein said supporting means has a
plurality of openings aligned with the keys, and including a
tubular resilient member for each key having a reduced portion
mounted within an opening in said supporting means.
9. The structure of claim 4 including further stop means supported
on the frame structure and adapted to engage the key to limit said
further movement thereof.
10. The structure of claim 4 wherein said resilient member is
formed of neoprene.
11. A keyboard structure in accordance with claim 4 further
including, a first circuit board secured to the frame structure and
extending generally parallel to the plane of the keys, said first
circuit board including components and conductors thereon, a second
circuit board secured to said first circuit board and extending at
substantially a right angle thereto, said second circuit board
including components and conductors thereon with said conductors on
said second circuit board being connected to said conductors on
said first circuit board, elongated resilient conductors supported
on said second circuit board and connected to the conductors
thereon and individually coupled to the keys, and fixed contact
means cooperating with said resilient conductor means to form
electric switch means operated by said keys.
12. In a keyboard structure for an electrical musical instrument
including a frame structure, a plurality of keys pivotally mounted
on the frame structure, and electric switch means coupled to the
keys for actuation thereby, the combination including;
stop means on each of said keys,
resilient means positioned to be engaged by said stop means upon
movement of a key to a first position to actuate the switch means
coupled thereto, and
means for supporting said resilient means on the frame
structure,
said resilient means forming a wall extending generally in the
direction of movement of said stop means and engaged thereby as the
key moves to said first position, said resilient means having a
portion providing resistance to further movement of the key beyond
said first position which flexes to permit further movement of the
key through said first position to a second position in response to
a predetermined pressure applied thereto by the key.
Description
BACKGROUND OF THE INVENTION
Electronic organs, pianos and other electrical musical instruments
include keyboards with switches which are operated to activate tone
generators, or to key signals therefrom, to selectively provide
signals representing various musical notes. One such keyboard is
described and claimed in U.S. Pat. No. 3,251,923, issued May 17,
1966 to F. M. Lund, and assigned to the assignee of the present
invention. As the musical instrument art has developed, it is
desired to provide keyboard assemblies with switches and circuits
which are of simple and compact construction, and which can be used
to provide musical effects not now available in small
instruments.
It has also been desired to provide keyboards for electronic
instruments, which may be electronic pianos, which have the same
touch and response to the musician as that of standard piano key
and action assemblies which have been available over many years.
One such characteristic is second touch, which is produced in a
piano key and action assembly when the coupling from the key to the
hammer of the piano action is let off, with the key still being
movable after the let off until a positive stop is reached. This is
sometimes referred to as "after touch." This feel has not been
present in keyboards for electronic musical instruments, wherein
the key moves from a normal position to an operated position at
which the key engages a stop.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved
keyboard and switch assembly for an electronic musical
instrument.
Another object of the invention is to provide a keyboard and switch
assembly wherein circuit boards for electronic circuits are
arranged with the keyboard and key switch structure in a compact
assembly.
A further object of the invention is to provide a key-board for an
electrical musical instrument wherein the keys when operated
provide a second touch feel to simulate the action of a piano key
and action assembly.
A still further object of the invention is to provide a keyboard
and key switch assembly wherein the keys have a second touch feel,
and the switch structure provides a further contact engagement when
the key moves beyond its normal actuated position.
In practicing the invention, a musical instrument key-board and
switch assembly is provided including a frame having keys pivotally
mounted thereon and a circuit board structure supported thereby.
The circuit board structure includes a first board generally
parallel to the frame, and a second board perpendicular to the
first board and having resilient conductors extending therefrom
which are moved by actuators coupled to the keys. The conductors
are moved to engage bar conducting rods, or bus bars, to provide
connections from the circuits on the circuit board to the bus bars
which are connected on the music instrument circuitry. A resilient
stop is engaged by the keys when they are moved to an operated
position, with the resilient stop being compressible to allow
movement of the keys to a second position providing a second touch
feel, as in a piano key and action assembly. The resilient
conductors may cooperate with the actuators connected to the keys
so that one or more connections are established when a key is moved
to its normal operated position and an additional connection is
established when the key is moved to the second position.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view showing the keyboard and switch
structure of the invention;
FIG. 2 is a cross-sectional view of the keyboard of FIG. 1;
FIGS. 3 and 4 are cross-sectional views showing a key in different
operated positions;
FIG. 5 is a view along line 5--5 of FIG. 4 and shows the switch
conductors;
FIG. 6 shows the actuator for the switch conductors;
FIG. 7 shows a modification of the resilient stop structure of FIG.
1; and
FIGS. 8, 9 and 10 illustrate a further embodiment of the resilient
stop structure.
DETAILED DESCRIPTION
In FIG. 1 there is shown a perspective view of a section of a
keyboard and switch structure in accordance with the invention.
FIG. 2 is a cross-sectional view of this structure. A key frame or
key bed 10 supports a plurality of keys 11 thereon, which are
pivoted on an upturned portion 14 at the rear of the key bed 10.
The keys 11 have a metal channel 12 with a plastic cover 13 on the
front thereof. The portion 14 has pivot portions which cooperate
with V-shaped notches 16 (FIG. 2) in the metal channels 12 of the
keys. A spring 18 is connected to the portion 14 of the key bed and
to the rear of each channel 12 to hold the front ends of the keys
11 upward. The keys and key frame may be generally like that shown
and claimed in U.S. Pat. No. 3,251,923, referred to above.
Secured at the front of the key bed 10 is another upstanding
portion 20 having individual stops 22 thereon. The stops have
thereon a sleeve 23 of resilient material which is engaged by an
inturned portion 17 on the channel 12 of each key, to limit the
upward movement of the fronts of the keys. In FIG. 1, the key
associated with the first pivot portion and stop 22 has been
removed so that these parts are more clearly shown.
Secured to the underside of the key bed 10 is a printed circuit
board 25 having circuit components 26 thereon. The board 25 is
supported on the key bed or frame 10 by insulating posts 28.
Secured to the board 25 and extending at right angles thereto is a
second board 30 having additional circuits and components 27, which
may be connected to the circuits on the board 25. Extending from
the board 30 in a direction substantially parallel to the keys are
elongated resilient conductors or rods 32. These rods are connected
to circuits on the board 30, and extend through openings in
actuators 34 which are secured to the keys. The actuators 34 are
connected to studs 35 extending downwardly from the key channels
12.
Fixed conducting rods 36, which may be supported on insulators 38
which are secured to the key bed 10 by posts 39, are engaged by the
resilient conductors 32 when the keys 11 are operated. As the
actuator 34 moves downward it will move the conductors 32 downward
into engagement with the transversely extending rods 36. As the
conductors 32 can slide freely within the openings of the actuator
34, no tension is placed thereon, and the resilient conductors are
capable of the large number of movements required of a switch for
use with a musical instrument keyboard.
FIG. 3 is a cross-sectional view like FIG. 2, except showing the
key 11 in the actuated position. It will be noted that one of the
conductors 32, which is designated 32a, engages the cross rod 36a
to provide a connection from a circuit on the printed circuit board
30 through the bus 36a to provide an operative circuit connection.
As previously stated, the circuits on the circuit board 30 can be
interconnected with circuits on circuit board 25, to provide
various circuit configurations as may be required. It will be noted
that when the key 11 is depressed as shown in FIG. 3, the extension
17 on the flange of the channel 12, which limits the upward
movement of the key as it engages stop 22, engages an upstanding
flat resilient member 40 to limit the downward movement of the key.
The member 40 forms a wall which is supported in a channel like
support 42 which is secured to the front of the key bed 10 along
with the stop member 20.
The resilient stop 40 may be made of a material which can be flexed
to permit further movement of a key which engages this stop, as
shown in FIG. 4. In FIG. 4 the normal unoperated position of the
key is shown by dot-dash lines, and the operated position at which
the extension 17 on the key channel 12 engages stop 40 is shown by
dashed lines, both of these positions being above the position
shown in FIG. 4. In the position shown in FIG. 4, the key channel
12 is moved downwardly until the web of the channel 12 engages the
resilient stop 23, which forms a limit to downward movement. As the
key moves from the position shown in FIG. 3 to the position shown
in FIG. 4, the actuator 34 moves the flexible conductors 32 further
down so that the conductor 32b engages the rod 36b. The conductor
32a will still be held in engagement with the rod 36a, but will be
flexed to a greater extent. It will therefore be apparent that a
further connection can be established from the printed circuit
board 30 through the conductor 32b to the bus 36b when the key is
depressed to the position shown in FIG. 4.
FIGS. 5 and 6 show the structure of the resilient conductors 32 and
the conducting rods 36, and the supports and actuators therefor. As
previously stated, the conductors 32 can slide within the openings
in actuators 34 so that there is no tension on the conductors
32.
In FIG. 7 there is shown a modified construction of stop member 40,
which is identified as 43. In the construction, slits 44 are
provided in the member 43 intermediate the portions engaged by the
individual keys. As previously stated, the extensions 17 on the key
channels 12 will engage the upper edge of the resilient stop member
40. By providing slits between the portions engaged by the
individual keys, the wall portion under each key can flex
independently of the portions under adjacent keys. This does not
cause the deflection of the portion under an adjacent key when one
key is depressed. Accordingly, each key reaches the stop at the
same position, whether or not adjacent keys are operated. The
desired resistance to further movement can be obtained by selecting
the material for the member 43. A material which has been found to
be suitable is neoprene.
FIGS. 8, 9 and 10 show a second embodiment of the stop structure
wherein an individual stop is provided for each key. As shown in
FIG. 8, a tubular resilient member 50 is provided directly under
the extensions 17 of the channel 12 of each key. These resilient
members are mounted on a support 52 which may be secured to the key
frame 10, in the same manner that the support 42 is secured thereto
as illustrated in FIG. 2. The tubular member 50 is shown in FIGS. 8
and 9, and has a reduced portion 54 which fits into an opening in
the support 52, with shoulders on either side so that the member 50
is held in place on the support 52. The upper wall portion 55 of
the member 50 is of tubular configuration having an opening 56
therein, so that the member can be compressed to be inserted up
through the opening in the support 52. The bottom end 58 may be of
larger diameter than the top portion 55, and may have an opening 59
therein if desired which joins with the opening 56 to increase the
resilience and facilitate the insertion of the member 50 in the
support 52.
In FIG. 10 the resilient stop 50 is shown in the compressed
position which takes place during the second touch movement. The
material from which the tubular member 50 is made can have the
required resiliency to provide a significant stop action when the
portion 17 of the key channel 12 engages the same, and to be
compressible when a further force is applied thereto. A suitable
material for this use is neoprene. When the resilient member 50 is
compressed, the key will continue to move downwardly until the top
of the channel 12 engages the resilient sleeve 23, as described in
connection with FIG. 4.
The embodiment of the stop members shown in FIGS. 8, 9 and 10 can
be used in place of the resilient member 40 and the support 42 in
the structure shown in FIGS. 1 to 4.
The keyboard for a musical instrument which has been described is
suitable for use in many electrical musical instruments, such as
electric organs and pianos. The circuit board and switch
construction provides flexibility for different connection
arrangements which may be desired. The resilient stop structure
provides a second touch, or after touch, characteristic so that the
feel to the musician is very similar to that of a piano which has
an action with hammers for striking strings. The keyboard and
switch structure is relatively simple and can be economically
produced, and at the same time provides the characteristics
desired.
* * * * *