U.S. patent number 3,738,216 [Application Number 05/084,588] was granted by the patent office on 1973-06-12 for keyboard for musical instruments.
This patent grant is currently assigned to Jasper Electronics Manufacturing Corporation. Invention is credited to James E. Blessinger, Mathew A. Slaats.
United States Patent |
3,738,216 |
Slaats , et al. |
June 12, 1973 |
KEYBOARD FOR MUSICAL INSTRUMENTS
Abstract
A keyboard structure especially for musical instruments and the
like, in which an upwardly opening metal channel is supported on a
leaf spring at the back to permit vertical movement of the channel
while a downwardly opening plastic cap member is mounted on top of
the metallic channel and projects from the front end of the
channel. A chassis is provided supporting the leaf spring and also
having upward and downward stop arrangements for limiting the
vertical movement of the key and also includes a lateral guide for
the key.
Inventors: |
Slaats; Mathew A. (Jasper,
IN), Blessinger; James E. (Jasper, IN) |
Assignee: |
Jasper Electronics Manufacturing
Corporation (Jasper, IN)
|
Family
ID: |
22185931 |
Appl.
No.: |
05/084,588 |
Filed: |
October 28, 1970 |
Current U.S.
Class: |
84/433 |
Current CPC
Class: |
G10C
3/12 (20130101) |
Current International
Class: |
G10C
3/12 (20060101); G10c 003/12 () |
Field of
Search: |
;84/423,430,432-436 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Wilkinson; Richard B.
Assistant Examiner: Gonzales; John F.
Claims
What is claimed is:
1. A keyboard structure, especially for a musical instrument, and
including a key, said key comprising an upwardly opening channel
shaped metallic supporting member having a bottom wall and
upstanding legs and extending forwardly from the rear of the key
and a downwardly opening channel shaped cap member having a top
wall and dependent legs and extending rearwardly from the front of
the key, a portion of the lengths of said members being coextensive
and means fixedly interconnecting said members, the top wall of
said cap member resting on the upper edges of the legs of said
supporting member and the legs of said cap member closely embracing
the legs of said supporting member, a tab upstanding from the rear
end of the supporting member, a stationary chassis member having an
upstanding flange disposed beneath said tab, a leaf spring engaging
both said flange and tab in face to face engagement therewith and
fixed thereto, said flange terminating at the top near the bottom
of said tab whereby a short length only of said leaf spring is
exposed to form a pivot region for said key, a stud dependent from
said supporting member, an aperture in said chassis member through
which said stud extends, an abutment element on said stud beneath
said chassis member forming an up stop for the key, and sound
deadening means interposed between the upper side of said abutment
element and the underside of said chassis member.
2. A keyboard structure according to claim 1 in which said leaf
spring is detachably connected to said supporting member, and said
aperture includes an enlarged region disposed in the forward
direction from the normal location of said stud and larger in
diameter than said abutment element whereby upon detaching said
supporting member from said leaf spring the said key can be shifted
in the forward direction and removed from the chassis member by
drawing the abutment element upwardly through said enlarged
region.
3. A keyboard structure according to claim 1 in which said bottom
wall of said supporting member is provided with a longitudinally
elongate guide bushing near the front, said guide bushing being
disposed on the upper side of the bottom wall and between the legs
of the supporting member, and a stationary guide pin upstanding
from the chassis member and extending into said elongate guide
bushing and slidably engaging the laterally opposite sides of said
guide bushing.
4. A keyboard structure according to claim 3 in which said guide
pin in at least the region engaged by said guide bushing has a
smaller dimension in the lateral direction than in the fore and aft
direction so as to be readily bendable for precise lateral location
of the front end of said key and is rotatable to adjust the side
play of the key.
5. A keyboard structure according to claim 3 which includes sound
deadening stop means mounted on the upper side of said chassis
member and engageable by the bottom of said key in depressed
position thereof.
6. A keyboard structure according to claim 3 in which said guide
bushing has projections on the outside of the side walls engageable
with holes formed in the said legs of said supporting member to
hold the guide bushing in the supporting member, said guide bushing
being oval and wider across the narrow dimension than the lateral
distance between the legs of said supporting member when relaxed
and having the side walls compressed into parallel relation when
mounted in said supporting member between the said legs thereof.
Description
The present invention relates to keyboard structures and is
particularly concerned with a keyboard structure for a musical
instrument such as an organ or piano.
Keyboards are, of course, well known and have heretofore taken many
different forms. In most pianos the key is pivotally supported and
is forced downwardly at the back by the weight of the action which
the key actuates when it is depressed in the front. In electric
organs, however, there is no action which the key actuates but,
rather, a switching arrangement is actuated by the key which
controls the sounds issued by the organ. In such a case, it is
usually necessary to spring the key toward rest position, while
providing upper and lower stop arrangements for halting the key at
opposite ends of its travel.
Instrument keys which are returned under the force of a spring have
heretofore been devised in various manners and included are
arrangements wherein the key is biased toward rest position by a
leaf spring.
With the advent of electric organs, in particular, keys have been
made of a combination of metal and plastic, the metal often being
in the form of a T-shaped or an inverted U-shape and with the
plastic taking the form of a cap member mounted thereon. Such keys
are satisfactory with regard to wear and appearance but lack the
rigidity against twisting and bending that is characteristic of,
for example, a wooden piano key according to the prior art. The
metal and plastic instrument keys do, however, offer the advantages
of lightness and low cost to manufacture and ease of assembly and
repair as well as having a pleasing appearance and a pleasant
touch.
With the foregoing in mind, a primary objective of the present
invention is the provision of an instrument key and supporting
structure thereon of the nature referred to which is improved in
operation and ease of manufacture over what has been available
heretofore.
Another object of the present invention is the provision of an
instrument key, especially for electric organs, in which a plastic
cap is mounted on a metal support member with the cap and support
member being so arranged as to provide for great strength and
rigidity against bending and twisting while still remaining quite
light and inexpensive.
A still further object of the present invention is the provision of
an instrument key and a supporting structure therefor in which
adjustment of the key is readily possible in order to place it in
exactly the right position to bring it into conformity with
adjacent keys and to insure proper movement thereof.
Still another object of the present invention is the provision of
an instrument key and supporting structure therefor in which the
key can be adjusted in the fore and aft direction as well as
laterally and in the up and down direction, thereby providing for
complete adjustability of the key in any direction necessary to
place it in the proper position.
Still a further object of the present invention is the provision of
an instrument key, especially for an electronic organ or the like,
in which the bias on the key can readily be adjusted so as to adapt
the touch of the key to the preference of the player.
The foregoing objects of the present invention as well as still
other objects and advantages thereof will become more apparent upon
reference to the following detailed specification taken in
connection with the accompanying drawings in which:
FIG. 1 is a somewhat schematic perspective view showing a key and
support structure therefor according to the present invention;
FIG. 2 is a side view of the key and supporting structure, partly
in section;
FIG. 3 is a plan section indicated by line III--III on FIG. 2,
showing a novel feature in respect of the guide at the front end of
the key;
FIG. 4 is a transverse section showing an alternate method of
connecting the cap of the key to the support channel; and
FIG. 5 is a fragmentary longitudinal sectional view at the rear end
of the key, showing the provision of an adjustment for the fore and
aft position of the key.
DETAILED DESCRIPTION OF THE INVENTION
Referring to the drawings somewhat more in detail, in FIGS. 1 and 2
there is shown a stationary support member 10 of an instrument
having a front member 12 upstanding therefrom. Mounted on
stationary member 10 is a chassis generally indicated at 14 and
forming a part of the present invention. Chassis 14 comprises a
generally rectangular wooden front rail 16 and a metal chassis
plate 18 mounted on top of the rail 16 and extending rearwardly
therefrom and at the rear end being turned up at an angle to form
laterally extending rib 20.
Attached to the underneath side of chassis member 18 toward the
rear end, in any suitable manner, is an angular transversely
extending support bracket 22 which is fastened to stationary member
10 as by screws 24. Member 18 in the transverse direction
preferably spans a unit of 12 keys, making up an octave of the
keyboard. This forms a convenient size in which member 18 can be
made and forms a convenient size for machining and assembly
work.
It will be understood, therefore, that in looking at, for example,
FIG. 1, while only a single key is shown, specifically, either the
key B or the key E, the usual member 18 will actually support a row
of 12 keys consisting of seven white keys and five black keys.
Where less than a full octave of keys is encountered at either end
of the keyboard, a special member 18 with the requisite number of
keys is provided. In such a case, the end key may be of a special
type.
According to the present invention, each key is formed of a metal
channel 26, steel for example, which in cross section is U-shaped
and which, at the rear end of the key, has a projecting tab 28
turned up substantially at right angles to the length of channel
26. Tab 28 may be integral with channel 26, or it may be separate
therefrom and attached to the channel, as by a screw, as will be
described hereinafter. Tab 28 preferably has struck up portions 29
to engage the sides of a leaf spring element. Tab 28 has a washer
30 attached thereto by means of screw 32 and between the washer 30
and tab 28 is clamped the upper end of a leaf spring element 34,
which is preferably in the form of a finger extending upwardly from
an elongated strip.
The lower end of the spring element lies along the rear side of the
upturned rib 20 at the rear end of chassis member 18. A spring
retainer plate 36 is disposed on the opposite side of the lower end
of the leaf spring from upturned rib 20 and is held in place by
rivet means 38. Individual spring retainers 36 can be provided for
individual spring leafs 34 but it is advantageous for spring
retainer 36 and the leaf spring member to extend the full length of
member 18 and to be secured to the upturned rib 20 by rivets
distributed along the length of member 18.
The aforementioned channel 26, as will best be seen in FIG. 2, is
the same width from end to end, but deepens toward the front end of
the key and is adapted to receive thereover toward the front of the
channel a plastic key cap 40 which may be of any suitable color but
which is usually white. The key cap is preferably cemented to the
channel but may be secured thereto in any other suitable manner.
Cementing the cap in place assists in making the key structure
stiff against bending. An alternate method of connecting the cap to
the channel is shown in FIG. 4 wherein screw 42, toward the rear
end of the key extends through the cap and is threaded through the
bottom wall of support channel 26.
Fixed to the bottom of channel 26 and extending downwardly
therefrom, somewhat at an angle so as to be substantially
tangential to a circle drawn about the point of flexure of spring
34, is a threaded stud 44 which extends through an aperture 46 in
member 18. On the underside of member 18 stud 44 carries a felt
washer 48 and an adjustable stop nut 50. Aperture 46, as will be
seen in FIG. 1, is keyhole shaped with the large end of the keyhole
being large enough to accommodate the felt washer 48 and nut 50,
while the rear end of the aperture is only large enough to
accommodate stud 44.
Because of the described configuration of the aperture 46, the
removing of screw 32 will permit the key readily to be removed from
the support chassis merely by moving the key forwardly until nut 50
aligns with the large part of the aperture, and then lifting the
key upwardly. Similarly, the key can be replaced by reversing the
aforementioned steps.
Mounted on top of stationary member 18 toward the front is a strip
52 of foamed elastomeric material which serves as a downstop for
the key. It will be apparent that the strip 52, and the combination
of stud 44, felt washer 48 and nut 50 provide for down and up stops
for the key and with at least the up stop thereof being adjustable
so that the key can be stopped in exactly the right upper
position.
Forwardly of strip 52 is a guide pin 54 which has a cylindrical
lower end driven into rail 16 and a somewhat flattened, or oval,
upper end. The upper end of guide pin 54 will be seen in plan
section in FIG. 3. The pin 54 extends through an elongated aperture
56 formed in the bottom of rail 26 and through an elongated guide
bushing 58 mounted on the bottom wall of channel 26.
The described arrangement of the guide pin 54 and the bushing 58,
which engages the sides of the guide pin, guides the key in its up
and down motion. At the same time, due to the reduced lateral
dimension of the upper end of pin 54, the pin can readily be bent
laterally in one direction or the other, thereby precisely to
adjust the position of the key in the lateral direction relative to
adjacent keys. This feature is quite important in respect of
providing a keyboard having the best possible appearance and
action.
The guide bushing 58, which is also oval when relaxed, is mounted
in the guide channel between the side walls thereof and has two
knob-like projections 59 receivable in holes 61 in the key channel.
The bushing is held with the sides parallel. The pin 54 can then be
rotated to get the best engagement of the pin with the sides of the
guide bushing and thereby control the lateral play of the key.
The channel 26 and the plastic cap 40, when placed together, and as
will be seen in FIG. 4, form a hollow box-like channel which is
extremely rigid against bending and twisting. The features of
stiffness against bending and twisting of the key is quite
important to the proper feel and operation thereof and is
distinctly better with a key constructed according to the present
invention that one in which the channel 26 opens downwardly or when
it is formed to a T or an L shape. At the same time, no lightness
is lost in arriving at the rigid beam-like nature of the key
according to the present invention.
Fore and aft adjustability of the key can be provided for as shown
in FIG. 5 by mounting within the metal channel of the key indicated
at 26a an L-shaped bracket 60 having a slot 62 therein through
which a screw 64 passes which connects the L-shaped bracket to the
key channel. The rear end of L-shaped bracket 60 is turned up and
is secured to the respective leaf spring 34a for the key. The slot
could, of course, be provided in the key channel and the screw
threaded into the bracket.
It will readily be evident, upon reference to FIG. 5, that the key
of which channel 26a forms a part can readily be adjusted somewhat
in the fore and aft direction merely be loosening screw 64 and
positioning the key in the desired position and then again
tightening screw 64. The modification of FIG. 5 provides an
additional adjustment whereby all of the keys of a keyboard can
easily be precisely aligned in the fore and aft direction.
In either of the modifications illustrated and described, the
upturned tab at the rear end of the key to which the upper end of
the respective key biasing leaf spring is attached, can be bent in
the fore and aft direction with a simple tool, thereby to adjust
the bias on the key. Thus, if a player wishes a relatively stiff
action, the tabs 28, 60 are bent in one direction and if the player
wishes a softer, or freer, action the tabs 28, 60 are bent in the
opposite direction.
A keyboard constructed according to the present invention is thus
readily adjustable to meet individual specification, and which are
often encountered especially with performing players as, for
example, professional type players.
Each key of the keyboard is easily removeable and replaceable and
is adjustable in all directions while the keyboard structure is, at
the same time, inexpensive.
For use with pianos, the key would include an arrangement for
actuating the respective hammer in the piano action while for use
with an organ, the key would include an arrangement for actuating a
respective valve or switch structure.
Modifications can be made within the scope of the appended
claims.
* * * * *