KR820001841B1 - Keyboard construction for pianos - Google Patents

Abstract

The keyboard for pianos and similar musical instruments has key shanks formed of structural foam containing glass fibers, there being only one shank construction for all the white keys and another for all the black. The shanks are connected, at their outer ends, to selfpositioning hollow key caps. Each shank rests, at a laterally thickened central portion, on a synthetic resin balance rail from which an integral balance pin porjects into a slot in such central portion. The outer end of each shank rests on a synthetic resin guide rail having a guide pin formed integrally therewith and extending into the shank.

Description

Piano Key Board

1 is a perspective view showing the structure of the keyboard of the present invention.

FIG. 2 is a vertical sectional view along line 2-2 of FIG. 1 showing a sound generator installed on a hammer.

3 is an enlarged vertical cross-sectional view showing one white key, a lower balance device and a guide rail.

4 is a perspective view showing an shank or a lever of one white keyboard and an exploded view of several white keyboard caps installed on the shank.

FIG. 5 is a view corresponding to FIG. 4 showing the black key shank and the black key cap engaging. FIG.

6 is a plan view of the outer and middle portions of the keyboard.

7 is an enlarged cross sectional view along line 7-7 of FIG.

8 is a partial longitudinal cross-sectional view showing a device for adjusting the strength of touch of a keyboard.

9 is a block diagram of a forming apparatus.

The present invention relates to a keyboard for piano and similar key structures.

Electric mini or stage pianos are moved from place to place by professional pianists and have the great advantage that the same precision instruments are played every night. However, this means that the piano must be able to cope with mechanical and thermal shocks. For example, when the piano falls, a mechanical shock occurs. An example of a thermal shock is that if a pianist carries a piano in his trunk on a desert, the temperature in the trunk will exceed 93.4 ° C. After that, if the pianist parks at the airport and boards the plane, the cargo compartment temperature will be about -57.8 ℃.

The piano should be configured to respond to the above shocks and the keyboard should not break or wear even if it is beaten badly millions of times by rock musicians. Furthermore, it is especially required to be resistant to abrasion and not to bounce off the balance rail when the outer part of the shank is knocked out.

Especially important is that the keyboard should not make noise. There is no friction with the case, and only the sound produced by the player is heard, and the player is carried in the music. This requirement referred to here applies not only to electric pianos, but also to ordinary pianos and similar keyboard instruments in which the keys of the present invention are used.

Another requirement for the keyboard is that it can be mass-produced quickly with great precision, inexpensive and consists of fewer parts. Considering that there are 88 keys on each instrument, you only need to save a few seconds for each key. Keys have the important advantage that they can be quickly and easily removed and replaced from the instrument and that nothing is required except to replace the key at the exact position of the key used before.

The keyboard has been known to players and tuners for decades as a wooden keyboard, and has generally been operated, assembled and disassembled. Thus, for example, a pin is provided that protrudes upwards in a slotted shank without the extreme noise, wear, price and other characteristics of wood shank and metal pins. The slot configuration allows the key to be installed and removed in seconds without creating any continuous or discontinuous speeds.

The characteristic of a mini electric piano is its lightness. Thus, for example, it is important to remove solid and heavy plywood, reducing weight and lowering cost.

Of course, the keyboard should be played well with a good feeling for the player. The player is very interested in touch, balance, and power. Regarding touch, it can be seen that some of the pianists like to have light touches and others have different requirements, like heavy touches. It is important to satisfy special merchants that the touch of the piano is easily changed by the operator at almost no cost. In particular, the weight of each key must equal the weight of each other's height. So that each key has the same feel or touch. This touch should be similar to the touch of a wooden keyboard.

There are a number of known patents that introduce piano keys made of synthetic resins, metals, and combinations thereof. However, to date, the piano keyboards produced commercially by all producers are mainly wood.

Shanks in particular are made from wood. The balance pins and guide pins are steel parts driven in the maple part and there are many bushings inserted into the shank.

Like price, noise and many other factors mentioned above, wear is a problem.

The keyboard of the present invention solves these problems, provides a high-quality synthetic piano keyboard, and enables mass production.

The present invention will be described in detail with reference to the drawings. In FIG. 1, reference numeral 10 shows a bottom wall portion of a cabinet or housing having a piano keyboard and a piano sounding operation device (action portion) connected thereto. It could be the case of a large cabinet used for home use, or the bottom wall of an electromechanical piano called the wall part "small". The wall portion 10 is preferably plywood.

The balance rail assembly 11 and the guide rail assembly 12 are attached on the wall portion 10 to driveably guide the shank lever portion 13 of the black piano key and the shank portion 14 of the white keyboard. The shank portion is suitable for operating an action portion of an electromechanical piano or a conventional acoustic piano. In the structure shown, the shank acts on the hammer 16 to hit the acoustic generator 17 (FIG. 2) of the electromechanical piano having a tuning fork connected to the machine-electric energy converter.

The balance rail assembly 11 has a synthetic resin pin 18 penetrating in the longitudinal slots 19 of the shanks 13 and 14. The guide rail assembly 12 has a pin 20 that extends in a longitudinal slot 12 in the shank portion. Due to the special materials, sizes, tolerances and other factors detailed below, there is no need to install bushings in the slots 19 and 21, and also without noise after the knocking operation is extremely quiet and hit tens of thousands of times. Is played.

Referring to the balance rail assembly 11 in detail, it has a plurality of separate axially adjacent long rail elements 22 with their ends in an adjacent state. The rail element 22 and the balance pin 18 are integral with each other and are injection molded simultaneously with synthetic resin. Supported on the rails 22 around each pin 18 is a felt washer 23, wherein the shank portions 13 and 14 connected thereto are supported without noise in the central portion.

Various rail elements 22 are provided on the aluminum extrusion member (reinforcement rail) 26 which is continuously connected to the overall length of the keyboard.

As shown in FIG. 3, the extruded portion 26 is a mass channel type having a support flange 28 protruding inside the upper end portion and an integral side wall portion 27. As shown in FIG. Such a flange is located on the end of the rail member 22. In the illustrated embodiment, the ends of the synthetic resin rail elements are inclined downward from the center of each rail. The web of the channeled extrusion limb 26 is a flange, ie a key, which is located on the top surface of the wall portion 10 and protrudes downward so as to be selectively positioned on one of the two parallel machined channels 31, 32 of the wall portion. Has (29) In order to support all the members in the position shown, the rail element 22 is fixed by the metal screw 33 (FIG. 1) only to the above extruded member, and the extruded member uses the wood screw 34 to apply the wall portion 10. Is fixed directly to The wood screw 34 is not located on the rail element but places its head in a large hole in the rail element.

The guide rail assembly 12 also has a number of separately injection molded synthetic guide rail elements 36 that are integral with the guide pin 20. Each pin 20 attaches a felt washer 37 around it to form a stop for the shank portion to which it is connected. An aluminum extrusion member 38 similar to the extrusion member 26 having a side wall portion 39 and a flange 40 protruding therein is a milled groove 42 connected to the flange 41 of the bottom portion and the It is located on the wall part 10 of the predetermined position determined by 1 degree). Similar to the case of the balance rail assembly, the rail element 36 is fixed by the metal screw 44 (shown on the left side of FIG. 2) and the extruded member is fixed by the wood screw 45 and the wood screw The head is not on the rail but directly on the web of the extrusion member.

The balance pins 18 corresponding to the shank portions 13 of the black keys are staggered with respect to the balance pins corresponding to the shank portions 14 of the white keys. Accordingly, the guide pins 20 corresponding to the shank portions of the black keys are staggered with respect to the guide pins corresponding to the shank portions of the white keys. In all cases, the pins of the black keys are located inside the pins of the white keys. Moreover, the outer end of the shank portion of the black keyboard is placed on the lower portion than the rail element 36 on which the corresponding portion of the shank portion of the white keyboard is placed. Accordingly, as shown in FIG. 3, the rail element 36 has two heights, that is, a thick outer portion below the end of the white keyboard and a thin lower portion below the black keyboard.

In addition to the felt washers described above, a cushioning felt strip 46 is attached on the wall portion 10 to prevent the noise of the downward movement of the inner end of the key shank portion (as shown in FIG. 1).

It is emphasized that the felt material in the piano action apparatus of the present invention is used only in the compression direction to prevent noise. It is advisable not to place felt in any slot. Therefore, the felt is used without friction. Felts of this type are expensive to use, wear and collapse and actually generate noise during frictional operation.

The extruded metal channels 26 and 38 are of high strength and engage with other extrusion members described below and prevent the wall portion 10 from deforming to provide a support structure. Therefore, it is practical to use only the wall portion 10 which is the outer wall of the small piano or the bottom wall of the cabinet part of the home piano instead of installing a separate frame as used in the conventional structure sold by the assignee of the present application.

Channels 26 and 28 engage a very strong and rigid pivot trail 47 that provides drive support for all hammers 16. The rail also supports a number of damper springs 48 (FIG. 1). The pivot rail has a flange 49 which projects downward to be located in the groove 51 of the wall portion 10. This rail is fixed to a predetermined position by fixing members 52 such as screws.

Another presser member 53 (FIG. 6) is provided at each end of the wall portion 10 in a right angle position with respect to the presser members 26, 38 and 47. This extrusion member 53 is shown in one direction and the same one is provided at the percussion part of the keyboard and provides a support corresponding to the half part having a transducer and support structure connected to it of the acoustic generator 17 (FIG. 2). . In addition, the extrusion member of the end has a separate reinforcing effect to prevent deformation of the wall portion (10). The extruding member at its end is an angle member and is fixed to a predetermined position by a bolt or other suitable fastener shown as 54 in FIG.

Referring to the key shanks 13 and 14, these shanks are best shown in FIGS. 4 and 5 degrees.

Each has a rectangular body portion 55 whose cross-sectional shape is long in the longitudinal direction. At the inner end of each body portion 55, there is an operating portion 56 that extends upwards to act on the piano action portion of each key. In the action portion of the type shown in FIG. 2, the portion 56 as pointed out above acts to engage one protrusion of the hammer 16 which is pivotably attached.

At its central portion above the balance rail assembly 11, each shank portion has a laterally thick portion 57. Further, the portion 57 projects upwardly (above the height of the adjacent horizontal upper surface of the shank portion). The projection above the portion 57 is formed. As best shown in FIG. 6, the webs 55 of each shank are narrow in height, as shown above, so that large spacings 59 are formed on both sides of the laterally thick portion 57. However, the portion 57 is sufficiently inadequate enough to touch the nib (by thick) so that the gap 61 between them is narrow and barely in contact with the friction between the opposing surfaces of the adjacent portions 57. to be.

An important feature of the present invention is that from the synthetic resin of some blowing agents cooled in a mold in which the shank portions 13 and 14 form a common form of structural foaming, ie, corresponding to the shank portion 13 or 14. It is molded one by one. This amount of foam is relatively small and the resulting foamed product has a density greater than that of wood (sugar pine or basswood) that has conventionally been used to form the tall shank portion of wood. Synthetic resins also include short glass fibers which greatly increase the stability and strength of the size of the shank portion.

Synthetic resins, including glass fibers, are prefoamed to be under heat and pressure in a pressure chamber, shown in block form as number 65 in FIG. The valve 65a is then opened to inject and expand the hot pressurized foamed resin into the cavity 65b of the mold. The pressure chamber 65 preferably has a piston that increases the pressure. Next, cooling is performed (in the mold), and a coating having a thickness of about 0.76 to 1.27 mm is formed in the shank portion.

Since the slots 19 and 21 are formed during the casting process, the covering is present in the wall portion of these slots. Thus, the wall portion of the slot (and all parts outside the shank portion) is smooth, free of holes and relatively hard.

The body portion 55 is narrow in most of the overall length and has a large gap 59 therebetween, and the weight of the shank portions 13 and 14 is very close to the weight of the conventional wooden keyboard with similar inertia effects. The weight of each shank portion and cap connected thereto should not exceed 50% or more of the weight of each key in conventional wood keys.

The density of the structural foam resin used in the keyboard of the present invention is from about 0.32g / cm ³ or greater, preferably greater by more (for example, about 0.40g / cm ³ or more). Basswood and sugar pine used in conventional wood keys have a density of about 0.32-0.40 g / cm ³ . Because of the relationship as described above, the present application can obtain a keyboard that is not excessively heavy by using a repellent resin having a density of about 0.48 g / cm ³ or more.

Preferred synthetic resins for producing the shank of the present invention are partially foamed nylon, polypropylene, or ABS (acrylonitrile-butadiene-styrene). The glass fiber contains about 10-15% by weight and is preferably about 6.35 mm in length.

Due to the presence of the laterally thick shank portion 57 and the narrow gap 61 therebetween, the adjacent shank portions have a reinforcing action on each other, and when the piano is dropped or handled as a harsh condition, Prevent excessive bending or breakage. This action is referred to as the "domino reinforcement effect" even if adjacent articles do not reverse and support each other to oppose the domino effect.

In FIG. 7, the key of the lowest note of the piano is bent to the left until the shank portion of the next key is in contact with the portion 57 of the adjacent end 57. The curvature of the connected pins 18 is such that they contact the adjacent portion 57 and both pins 18 (shown on the left side of FIG. 7) act to prevent further bending. The stress reaches the maximum, and the part 57 of the leftmost pin 18 in FIG. 7 is bent until the stop convex 61 which is bolted to the extrusion member 53 contacts. The upward tension of the portion 57 acts to promote its domino effect and to be relatively less bent and in contact.

The pin 18 has elasticity rather than rigidity and has a large diameter due to fatigue resistance, attenuation effect and high strength. Important factors other than the above are described below.

At the outer ends of each shank portion 13 and 14 there is a key cap which is connected, which is configured with great strength to quickly determine the magnetic position for assembly. Initially, in the shank portion 13 of the black keyboard shown in FIG. 5, the entire body portion 55 of the outer end side is approximately equal in thickness with respect to the tip of the wall portion parallel to the slot 21 of the guide pin. Install grooves. Accordingly, because the slot 21 extends to the entire height of the shank portion, the narrow shank portions 63 and 64 are located inside and outside the slot. The hollow black cap is shown as 66, the inside of which is shaped to fit appropriately on the narrow portions 63 and 64, and also opens and closes the sides of the slot at the top thereof.

As shown at 67 in FIG. 5, the inside of the key cap 66 is made relatively wide in the slot 21 so as not to interfere with the guide pin 20. As shown in FIG. In this structure, the work of assembling the black keyboard firstly casts the shank portion, i.e., the key lever portion 13, and then a suitable adhesive is applied to the front end portion of the shank portion and the outer end portion of the key cap 66 is narrowed (64). Is completed by placing it in contact with the vertical stop surface 68 in the vertical direction.

In FIG. 4, the outer or front end portion of the shank portion 14 of the white keyboard does not need to maintain a special formation, but is rectangular as shown.

Each of these front ends is adapted to receive a suitable one of the various white keyboard caps 71. This white keyboard cap is hollow and has an inner rib or protrusion 76 at a suitable point, so that the action of automatically determining the complete position with respect to the shank portion 14 of the key cap during the bonding industry is automatically performed. The inner rib 76 has a relatively narrow width of the whole body 55 of the shank portion, but serves to determine the position in this way.

The resulting combination of black and white keys is as strong as a player like rock music would like.

One of the reasons for this stiffness is that the strength is obtained from the guide pin 20 extending beyond the slot 21 as a result of extending to the front end of the keycap to which each shank is connected.

Piano keyboard of the present invention has the advantages of excellent and uniform touch, simple structure, economical in manufacturing, low noise, high strength and long life as described above. All these advantages are achieved without the need for springs, metal bends, and other components that players and tuners are not familiar with. Thus, for example, a conventional wooden piano action portion has a balance pin and a guide pin, and is configured to remove the key by simply removing the cover and rails and then lifting the key from the pin as necessary. This advantage is equally made in the keys of the present invention. Moreover, in these keys the operator needed to number the entire keys and return the whole to its exact position. Instead, as above, all black keys are interchangeable, and all white keys with the same type of keycap are not interchangeable.

In the conventional piano keyboard, the balance pin and the guide pin are metal pins attached to maple wood. Generally, such metal balance pins have a diameter of about 3.18 mm, but each guide pin is usually a long horizontal cross section. For example, the horizontal cross section of the gun-circle of the guide pin has a short diameter of about 3.3 mm and a long diameter of about 5.3 mm. Since the cross section of the guide pin is elongated as described above, the long diameter is in the sleeve or bushing that is in hard contact with the shank portion of the key as the fatigue state increases so that it can be rotated to compensate for the fatigue state.

In the keyboard of the present invention, the balance pins 18 are cylinders of large diameter, each preferably having a diameter of about 6.35 mm. In other words, the communication is preferably about 6.35 mm in diameter. The guide pin 20 preferably has a diameter of about 4.57 mm, which is about 90% of the maximum diameter of the above-mentioned long circular guide pin of the prior art. The guide pin 20 of the present invention does not need to be rotated so as to have a cylindrical, downwardly integrated structure (same as the balance pin 18).

Guide pins and balance pins are preferably polished and formed from commercially available ABC (acrylonitrile-buradiene-styrene) resins. There is no need to use expensive plastics such as Delrin. Such pins are particularly strong with their large diameters. These pins are unreasonable, resilient, resistant to high impact and low pitched. The opposite domino effect suppresses the adverse consequences resulting from the elasticity.

It is important that the pin is tightly coupled in the slots 19 and 21 without bushings connected thereto. Although the shank portion is formed from structural foamed resin instead of plastic or wood, the noise is reduced, but large tolerances can generate noise in contact with the case.

The spacing of each tent between the respective pins and adjacent tentacles of the slots 19 and 21 is only about a thousandth of an inch. Therefore, in this embodiment (the diameter of the pin 18 is about 6.35 mm), it is about 6.60 mm, and the slot 21 of the guide pin is in this embodiment (the diameter of the pin 20 is about 4.75 mm). About 4.88mm. The slots 19 and 20 have a sufficient distance so that the pins never touch their ends. The bottom wall of the slot 19 has holes of small tolerance as important as follows.

In the above-described structure, the balance rail element 22 and the guide rail element 36 of the synthetic resin slide into the extruded member before being attached onto the wall portion 10 of the extruded parts 26 and 38. Metal screws 33 and 44 (FIG. 1) are used to hold the rail and its associated pins in position and to place felt washers 23 and 37 on their respective pins. An extruded member is attached to each slot on its wall portion 10. Next, all the joints are used. It is simply necessary to place the shank portion of each black key and the shank portion of the white key on each pin. For example, the shank portions for all "C" note keys on the piano can come from the same group, so there is no need to correlate the shank portions to each other.

In order to complete the assembly work, all the hammers 16 and the damping springs 48 are assembled in advance, and the extrusion member 47 is fixed by the fasteners 52 to which the grooves 51 are attached. The end extruding member 53 is attached to a predetermined position, and the half portion having all the sound generating portions 17 (FIG. 2) is attached to the predetermined position.

The key constructed in accordance with the present invention is capable of the following operations millions of times without generating a significant amount of fatigue, noise, and the like. The quietness of the action portion is remarkable and the touch and the touch is excellent, almost the same as the action portion of the wood despite the fact that the density of the foamable resin is larger than that of the conventionally used wood as described above.

One of the advantages is that the action portion is forced by the player and the key does not rise upward from the washer 23 of the balance rail even when the key is rapidly prominent. Therefore, there is no need to install any means (e.g., a support rail for fixing) the shank portion downward against the washer. The fact that the shank portion does not support the tendency to rise upward with respect to the balance rail is in contrast to the conventional structure installed on a rigid support notch cut in the lower surface of the shank portion.

Normally, one piano is mainly played by one player. This is suitable not only on professional player pianos but also on polite home pianos which are widely used by more than one user. One player is particularly fond of having a light keyboard and a relatively heavy touch. The keyboard of the present invention enables touch adjustment for piano sellers and players at home without difficulty and in particular without increasing production costs. The only case where the cost is increased is to install the extra groove 32 shown in FIGS. 1 and 8.

The figure shows a piano assembled for a light touch. This touch is light despite the fact that the shank portion is heavier than the shank portion of wood. The front part of such a lever part is relatively long. Therefore, the flange 29 of the extrusion member 26 is disposed in the rearmost groove 31 so that the lever arm protruding forward toward the player is long.

Particularly in FIG. 8, each slot 19 is clearly extended in the longitudinal direction of the key with respect to the balance pin 18, and the extension degree is always the slot of the pin 18 regardless of setting or performance. It is a length that does not reach the end of enough. The bottom of the slot 19 has the bottom surface of the shank portion and the flat wall portion 19 horizontally. Such a wall portion is particularly thin so as to prevent fastening even at small tolerances of the holes. The wall portion 79 has two circular holes 80 and 81, each of which is enlarged to sufficiently accommodate the pin 18 so as not to be fastened. Thus, this pin has a diameter of about 6.35 mm.

The holes 80 and 81 are spaced apart from each other in the long direction of the key enough to trigger a distinctly different touch. In the case of the present embodiment, when the pin 81 is displaced from one hole to another, the touch changes at a large rate even if the distance between the holes does not exceed about 9.53 mm, for example.

The two grooves 31 and 32 are spaced apart from each other by hole spacing, i.e., about 9.53 mm in this embodiment. Furthermore, the grooves 31 and 32 are positioned in a vertical position relationship with respect to the holes 80 and 81 so that wherever the flanges 29 are located in the grooves 31 and 32, Regardless, the holes 80 or 81 are always positioned so that the shank portions of the white or black keys are all in the same position as shown in the overall drawing.

For example, assuming that an instrument is constructed and configured as shown and displayed in a retailer's display room, the seller can accomplish this touch in minutes if a particular customer says he likes a heavy touch. This is done by removing the action section, the cover and the rails (not shown) of the keys, lifting all the keys from the balance rails and the guide rails connected to them and lifting them in a convenient place.

It is not necessary to keep the keys in order as above. Next, remove the relatively small number of wood screws 34 and simply move the extrusion member 26 to move the flange (Fig. 8) of the extrusion member 26 from the groove 31 to the groove 32. Move forward In other words, the extrusion member is moved to the position shown by the phantom line in FIG. Then all the keys are quickly returned on the rails so that the pins 18 are inserted into the holes 80 instead of the holes 81.

Next, all you need is to put the cover on the key and let the customer know that the touch has actually changed and became heavy.

Claims (1)

As detailed in the text and shown in the drawings, the outer end has a plurality of long key shank portions provided with a white key cap and a black key cap, and the key shank portion has a longitudinal slot 19 in the middle portion and is balanced. The rail 22 is located below the middle portion of the key shank portion and has a plurality of balance pins 18, each of which is connected to the key shank portion such that the key shank portion is pivotally restricted in a vertical plane around the middle portion. In known keyboard musical instruments configured to extend upwards in longitudinal slots, each of the key shanks 13 and 14 consists of a rigid structural foamed resin with a smooth and rigid sheath and at least 0.32 g. A keyboard for pianos, having a density of / cm ³ .

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