US3845683A

US3845683A - Keyboard for electronic musical instrument

Info

Publication number: US3845683A
Application number: US00396057A
Authority: US
Inventors: A Lehmann
Original assignee: Pratt Read Corp
Current assignee: Pratt Read Corp
Priority date: 1972-10-30
Filing date: 1973-09-10
Publication date: 1974-11-05
Anticipated expiration: 1991-11-05

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.

Description

United States Patent Lehmann Nov. 5, 1974 I KEYBOARD FOR ELECTRONIC MUSICAL INSTRUMENT 57 R T [75] mentor: Alfred Lehmann Clemson A keyboard for a musical instrment includes a frame 73 Assignec; p m Corporation, ivoryton, w1th keys plvotally mounted thereon, and a switch Conn structure secured to the frame mcludmg individual switch contacts actuated by the keys. A circuit board [22] Wed: sept- 1973 is mounted on the frame and extends in a plane paral- Appl 39 057 lel to the keys, with a second right angle circuit board mounted thereon having resilient switch conductors Related Apphcatlon Data extending generally parallel to the keys. An actuator [63] Continuation of Ser. No. 301,895, Oct. 30. 1972, for each key includes an insulator with openings abandonedthrough which the conductors extend. Fixed contacts in the form of bus bars are positioned to be selectively U.S. 7, engaged the resilient conductors to omplete ir- [5 Int. Cl. uits from the circuit boards A top tructure is pro- Field of Search 423, 430, vided for the keys including a resilient stop engaged 8 /432436, 39-4 1, L 1316- 29/624, when the keys are moved to the normal playing posi- 1 giifi tion. This movement of the key causes engagement of at least some of the switch conductors. The keys can References Cited be moved further to compress the resilient stop to pro- UNITED STATES PATENTS vide a second touch action. Additional circuits may be 2,599710 6/1972 Hathaway 29/625 established by the further movement of the keys- The 3,060,784 [0/1962 Holt 84/1.0l p Structure Can be in the form of a flat p y 3,095,465 6/1963 Holman 84/101 tending resilient strip which is engaged by a plurality 3,175,451 3/1965 Klann 84/433 of keys, and can have slits providing a separate por- 3,534,145 10/1970 84/117 tion for each key. Alternatively, a resilient tubular 3,671,658 6/1972 Ohno 84/].01 member can be provided f each key, to form h Primary Examiner-Stephen J. Tomsky Assistant Examiner-U. Weldon Attorney, Agent, or FirmMueller, Aiehele & Ptak stop.

12 Claims, 10 Drawing Figures KEYBOARD FORELECTRONIC MUSICAL INSTRUMENT 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 US. Pat. No. 3,251,923, issued May 17, I966 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. I

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 anormal 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. v

Another object of theinvention is to providea keyboard and switch assembly wherein circuit boards for electronic circuits are arranged with the keyboard and key switch structure in a compact assembly. I A further object of the invention is to provide a keyboard 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. v In practicing the invention, a musical instrument keyboard 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 movedby actuators coupled to the keys. The conductors are moved to engage bar .conducting rods, or bus bars, to provide connections from the circuits on thecircuit 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. I; 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 l1 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 ll upward. The keys and key frame may be generally like that shown and claimed in US. 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 down wardly 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 independentlyof 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 6 the same position, whether or not ad acent keys are operated. The desired resistance to further movement can be obtained by selecting the material for the member 42 is secured thereto as illustrated in FIG. 2. The tubular member 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 com pressible 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 isvery 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.

I claim:

I. 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.

Claims

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.

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.

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.