US2909093A - Piano action - Google Patents

Description

Oct. 20, 1959 c. w. ANDERSEN 2,909,093

PIANO ACTION 2 Sheets-Sheet 1 Filed Aug. 3, 1955 Oct. 20, 1959 c. w. ANDERSEN PIANO ACTION 2 Sheets-Sheet 2 Filed Aug. 3, 1955 mmv TOR. C zi/ford MMIJe/I QA M/w/ W iPA/A MM I n .5 @N i 5 I n J United States Patent PIANO ACTION Application August 3,1955, Serial N 0. 526,241 4 Claims. c1. 84236) This invention is concerned with the musical arts, and more particularly with improvements in piano actions.

The pianoforte, or piano, as it is commonly termed, is an extremely popular instrument, and it is found through out the world. In its conventional form, the piano is quite heavy and large. This makes it difiicu-lt to move conventional pianos, and it generally limits the use of pianos to first floor locations, and to the largest room in the house. This can be extremely undesirable from the standpoint of the student or casual pianist, and also from the standpoint of other persons occupying the same residence. Conventional pianos also are quite expensive, and are subject to detuning with age or by unfavorable climatic or atmospheric conditions.

It has been proposed that the foregoing difficulties be obviated or reduced by the provision of an electronic piano. It is known that a tuned reed having an electrical 7 potential applied to it and vibrated near a conductive member will form with that member a variable capacity giving rise to an electrical oscillation which can be translated into a musical tone. I have found that when such reeds are percussively actuated, remarkably realistic piano tones can be produced if the various elements of the electronic piano are properly correlated, and the electrical oscillations generated are properly amplified and converted into audio oscillations.

In order further to reduce the size, weight, and cost of conventional pianos, thereby fostering relatively easy carrying of the piano, I proposed replacing the cumbersome and costly actions of conventional pianos with greatly simplified actions. This invention is concerned primarily with such actions, although it will be understood that the principles are not necessarily limited to an electronic piano.

It is the general object of this invention to provide an improved and simplified piano action.

It is another object of this invention to provide an im proved main rail structure of unusual rigidity and therefore uniform action.

Yet another object of this invention is to provide a butt adjustment to insure that all of the keys when at rest will lie in a common plane regardless of manufacturing tolerances in certain parts of the piano actions.

It is another object of this invention to provide an improved adjustment for the damper mechanism for regulating the dampers, which adjustment is easily reached for adjustment.

Other and further objects and advantages of the present invention will be apparent from the following description when taken in connection with .the accompanying drawings wherein:

.section as taken along the line 3 3 in Fig. 2;

Fig. 4 is a fragmentary vertical sectional view on a greatly enlarged scale taken substantially along the line 4-4 in Fig. 3; and

Fig. 5 is a fragmentary perspective view of a portion of the piano action forming the subject matter of this invention.

Referring now in greater particularity to the drawings, and first to Figs. 1 and 2, there will be seen an electronic piano 30 constructed in accordance with the principles of my invention. The piano includes a case 32 preferably formed of wood or plywood and having at the front end thereof a keyboard 34 comprising a plurality of piano keys 36 corresponding to the keys of a conventional piano. The case also includes a fall board assembly 38 and a wire music rack 40 pivotally mounted thereon and capable of movement into position substantially against the keyboard 34 so that a fall cover (not shown) may be placed over the keyboard, fall board assembly, and music rack for transportation of the piano.

The piano case is mounted on four legs 42 which are detachably attached to the case, preferably by means such as threaded fastening means so that the legs may be removed for ready transportation of the piano. A foot pedal 44 for releasing the dampers is detachably connected to the piano by means such as a flexible cable 46 of the type known as a Bowden cable. The piano is provided with an electronic amplifier indicated generally at 47 in Fig. 3 mounted within the case 32 and connected to a loudspeaker 48 opening through suitable louvers (not shown) in the back of the case. Controls 50 are provided at the side of the case for the amplifier.

Further details on the foregoing may be found in my copending application Serial No. 495,113, filed March 18, 1955, and entitled, Electronic Piano.

A bed 52 is mounted on the bottom of the case on the inside thereof, and a balance rail 54 extends across this bed. The keys 36 of the keyboard 34 are pivotally mounted on the balance rail by means of the usual balance key pins 56 and felt pads or washers 58 surrounding these pins. The top surface of the balance rail is inclined as will be appreciated so as to support the keys in the inclined position shown in the drawings with the inner ends of the keys 36 resting on a felt pad 60 at the inner end of the bed. At the outer or front end of the bed 52 there is provided a front rail carrying a plurality of front key pins 64. A felt pad 66 is provided on the front rail at the outer edge thereof immediately beneath the outer ends of the keys 36. It will be appreciated that the felt pad or strip 66 prevents the keys from pivoting about the felt washers usually provided about the outermost of the front key pins. Under such circumstances the keys would rise from the balance rail 54 in an undesirable manner.

A pair of wood blocks 68 is mounted at the opposite ends of the piano case 32 on the inside thereof, the blocks being properly screwed and glued in place. A reed bar assembly 70 is mounted on these blocks. The reed bar assembly includes a reed bar 72 of massive construction, preferably cast of gray iron. The specific construction of the reed bar assembly is set forth in detail in my copending application Serial No. 514,348, filed June 9, 1955, and entitled Tone Generating Assembly for Electronic Piano. In somewhat general terms, the reed bar is generally rectangular in configuration and supports a plurality of vibratile reeds 74 (Figs. 4 and 5). The reeds are electrically connected to the bar, and the ends of the reeds are in capacitive relation with associated pick-up means 76.

The reed bar 72 includes a generally rectangular front rail 78 and a back rail 80. The front rail is connected to the back rail at the bass end by an integral side rail 82 (Fig. 3) and at the treble end by an integral side rail 84 (Fig. 4). The back rail 80 is provided with a shelf 86 which is set down somewhat from the top of the back rail 80. This shelf tapers from a maximum width at the bass end of the scale to a minimum width near the treble end. The bar 72 is very nearly rectangular in outline, but it is slightly wider at the bass than at the treble end. The bar preferably is provided near its midpoint with a reinforcing rib (not shown) integral with the front and back rails, and also may have depending portions beneath the front and back rails as shown in the drawings. From a practical production standpoint, the reed bar 72 preferably is cast, and then is machined to final dimensions. Satisfactory results have been obtained casting the bars of aluminum, or magnesium, or steel, or gray iron. Steel has been found to give the best results, but it is expensive and relatively difficult to machine while gray iron has been found nearly as satisfactory as steel, and is much less expensive, and is easier to machine.

The reeds 74 are made of steel and are mounted along the back bar 80 spaced above the shelf 86. The reeds vary in length, the bass reeds being the longest and the treble reeds being the shortest. All of the reeds include vibratile tongues 88 and integral bases 90. The bases are thicker than the tongues, and well defined internal shoulder 92 is formed between each base and tongue accurately to determine the portion of the tongue that will vibrate. The bass reeds and some of the middle reeds also are provided with weights 94 for lowering the frequency of vibration without making the reeds unduly large. These weights preferably are in the form of lead or the like which readily can be added to, as by adding lead in molten state, or can be subtracted from, asby filing, for properly tuning the reeds.

The reeds are mounted by means of cap screws 96 passing through the reed bases and threaded into the back rail. Washers are preferably carried beneath the heads of the cap screws, and the reeds are effectively connected electrically to the rear rail and project toward the front rail.

The pick-up means 76 previously referred to is supported along the top of the front rail 78 by means of an insulating strip or bar 98. The pick-up means com prises a conductive sheet, preferably of aluminum, or a plurality of sheets electrically interconnected, the sheet being held on top of the insulating bar 98 by means'of cap screws 100 passing through the insulating bar and threaded into the front rail 78. The cap screws are electrically insulated from the sheet 76 by means of suitable insulating bushings or washers. Fingers 102 are struck up from the sheet, except near the extreme treble end thereof, to form a comb like configuration comprising projecting fingers 104 and spaces 106 between the fingers. Near the treble end of the pick-up the material is simply struck out to provide the alternate fingers 104 and recesses 106 without the upwardly directed fingers 102. Thereeds 74 vibrate in the spaces 106 between the projecting fingers 104, and the conductive sheet of the pick-up 76 forms with the reeds a plurality of capacitors which vary in capacity in accordance with the vibrations of the reeds.

The reeds are mounted so as to be coplanar with the bottom surfaces of the pick-up. The amplitude of vibration of the reeds is such that they will vibrate below the pick-up sheet, but will not progress above the tops of the struck up fingers 102. It will be understood that in the case of the upper treble reeds the amplitude of vibration is so small that the reeds will not pass above the top surface of the sheet, and hence the upwardly struck fingers are unnecessary.

The reed bar assembly 70 is supported by the wooden blocks 68 at the opposite ends of the case. At the bass end of the bar a pair of wood screws 108 extends through the bar and through rubber washers 110 on top of fiber washers 112. The screws are threaded into the blocks 68. A main rail 114 extends across the piano and is held at its opposite ends by bolts 116 to a pair of blocks 118 which are screwed and glued to the opposite ends of the case. This main rail is made of wood in accordance with conventional practice, and being rather small and light weight, and carrying a plurality of parts as hereinafter will be brought out, tends to flex slightly in use. It readily will be understood that such flexing cannot be tolerated inasmuch as it would lead to unreliable action, and would cause the various keys to react differently beneath the pianists fingers in accordance with the position of the keys across the keyboard. In order to positively preclude such flexing of the main rail, there is provided a T-shaped reinforcing bar 120. The T- shaped reinforcing bar comprises a relatively thick flange 122 held on the back of the main rail by a plurality of screws 124 spaced horizontally in vertically displaced pairs along the length of the reinforcing bar 120. In addition to the flange 122 the reinforcing bar also includes a web 126 extending along the length of the flange substantially along the longitudinally center line thereof and disposed at right angles to the flange 122. It will be noted in the drawings that the web 126 is somewhat thinner than the flange 122. The reinforcing bar preferably is made of aluminum, and conveniently is extruded.

A plurality of whip flanges 128 is spaced along the bottom rear corner of the main rail, being secured thereto by wood screws 130 and a tongue-and groove joint. Each whip flange pivotally carries a whip 132. Each whip is provided beneath its forward end with a felt pad 134, and a capstan screw 136 on the inner end of the corresponding key 36 engages beneath each felt pad 134. The capstan screws preferably are provided with square or other noncircular shank portions for receiving a wrench to adjust the capstan screws up and down beneath the end of the whips. r

A jack or fly 138 is pivotally mounted on each whip adjacent the felt pad 134. Each jack or fly is provided with a tapered or wedge shape upper end or tip 140 covered by a layer of buckskin 142. The buckskin is skived, and often is of nonuniform thickness. The buckskin is glued to the tapered tip of the jack as will be appreciated.

Each jack or fly 138, specifically the buckskin 142 thereon, engages beneath a butt 144 of a corresponding hammer 146. Each hammer has a felt pad or striker 148 on the end thereof. A plurality of butt flanges 150 are spaced along the upper front corner of the main rail 114, and the butts are pivoted thereon. The butt flanges are secured similarly to the whip flanges by means of wood screws 152 and a tongue-and-groove joint.

Each butt is provided with a recessed portion 154, and with a jack engaging screw 156 which adjustably determines the time at which the jack or fly ceases to lift the butt and hammer. Each butt further is provided in its upper portion with a recess 158, and a rest position determining adjustment screw 160 is threaded diagonally from each such recess to a position near the lower rear corner of the butt and engaging the buckskin 142 of the corresponding jack or fly. The bearing of this screw 160 against each jack or fly maintains the upper corner thereof against the rounded tip or downwardly projecting end 162 of the corresponding adjustment screw 156. The tip of each jack or fly thus fits in a pocket 164 formed between the round screw tip and a flat undersurface 166 adjacent the recess 154. A butt spring 167 acts between each butt and its corresponding butt flange to hold the butt in its lower position as shown.

The hammers 146 are positioned to engage beneath the reeds 74 as will be appreciated. A damper lever 16.8 is positioned above each of the reeds except the top few at the treble end, and a damper in the form of a flat pad is placed on each'damper lever and engages a corresponding reed to damp the same. Each damper lever 168 is pivotally mounted. on a damper lever flange 172, and these damper lever flanges are positioned along the top rear edge of the main rail 114 and are held in position by means of wood screws 174 and a tongueand-groove joint. A spring 176 associated with each damper lever flange bears against the corresponding damper lever and holds it in damping position as shown in the drawings. Each damper lever 168 is connected to the corresponding whip 132 by means of a damper lever wire 178. Each damper lever wire 178 has a reyersely bent tail 180 at its lower end hooked through the inner or rear end'of the corresponding whip. The upper end of each damper lever wire 178 projects loosely through the rear or inner end of the associated damper lever 168, and an adjustment or regulator button 182 is threaded on the upper end thereof, a felt pad or washer 184 being positioned between the button and the top of the damper lever.

In the present instance, and as readily may be seen in Figs. 1 and 2, the top of the case 32 is removable, being held in place by means such as screws. All of the parts of the piano may be inserted in the case from the top, and when the piano is completely assembled except for the top, the regulator buttons 182 may be turned up or down on the damper lever wires to set the damper levers so that they engage the reeds when the keys are in their normal or undepressed position, without any lost motion being present between the dampers and the whips. It will be understood that damper adjustments heretofore known in the art have been at a low position where they could not readily be adjusted from the top of the piano as in the present instance.

Adjustment of the butt screws 160 and 156 is also made from the top of the piano. With the parts at rest position as shown in the drawings the screws 160 bear against the buckskin covered tips of the jacks or flies 138 and hold the buckskin covered tips in the pockets 164 against the spherical tips 162 of the screws 156. Adjustment of the screws 160 holds the tips properly in these pockets with the butts at the proper height regardless of variations in thickness of the buckskin 142. Each time a key is depressed the corresponding capstan screw 136 thereon pivots the corresponding whip in a counterclockwise direction as viewed in the drawings. This causes the jack or fly 138 to push up beneath the butt 102 and thereby to pivot the corresponding butt and hammer to carry the hammer into percussive engagement with the corresponding reed percussively to vibrate that reed. The last part of this motion is due to the inertia of the butt and hammer inasmuch as the spherical tip 162 of the screw 156 pushes the jack or fly from jacking position at a predetermined location. Threading of the screw 156 up and down in the butt will determine the exact location at which the spherical tip' 162 moves the jack or fly from the pocket 164 into the recess 154, jacking action thereby being terminated. The jack or fly remains tipped to the right so that it engages in the recess 154 and acts as a back check when the hammer and butt fall away from the reed under the influence of gravity upon rebounding from the reed.

Pivoting of the whip also pulls down on the corresponding damper wire 178 to retract the associated damper 170 from the reed to be struck by the hammer, thereby freeing this reed for vibration and tone generation. It heretofore has been noted that some of the treble reeds do not have dampers. The vibrational time of such reeds is so short that dampers are unnecessary. However, dummy damper levers are provided which are terminated short of the reed bar so that the feel of each key will be substantially uniform.

Provision also is made for simultaneously releasing all of the dampers for playing forte. The mechanism for attaining this end comprises a block 186 (Fig. 4) mounted at each end of the main rail by means such as suitable wood screws. The'pair of blocks pivotally supports a damper release rod 188 for eccentric rotation about mounting pins for rods 190. The Bowden wire 46 con nected to the foot pedal 44 is connected by means (not shown) to the pin at the treble end of the piano for eccentrically rotating the rod 188 to lift this rod against a pad 192 on the underside of each of the damper levers 168 whereby simultaneously to retract or release all of the dampers. In addition, there is provided a hollow pin 190 at the center of the rod 188 and an angle bracket 194 at the center of the main rail supports a felt pad 196 engageable beneath this pin to prevent flexing of the damper release rod 188.

The damper release rod and pivot pins are connected by means of a flexible wire 198 to the reed bar assembly 70 to preclude pick up and inadvertent tone generations due to variations in capacity between the parts. In addition, an aluminum shield 200 (Figs. 2 and 3) is secured to the reed bar assembly and overlies the same electrostatically to shield the reeds and pick-ups. The shield 200 is lined with felt as at 202, and a rubber bumper 204 on the front rail of the reed bar engages a portion of the shield 200 whereby to prevent mechanical vibration of the shield with consequent changes in capacity between the shield and other parts.

From the foregoing description it will be apparent that a portable electronic piano has been provided having an improved piano action, although it will be understood that the action might prove equally useful in applications other than electronic pianos. The improved action includes a light weight, yet stiff, main rail due to the reinforcing bar thereon. The entire structure is adjustable from above due to the positioning of the damper regulator button at the top of the structure, and due to the accessibility of the screws 156 and 166 from the top. The adjustability of these two screws insures a proper rest position of the butts and hammers, and also insures a proper release position for the rising butts and hammers regardless of variations in thickness in the skived buckskin 142, or in other parts.

It is to be understood that the specific example of the invention is for illustrative purposes only. Various changes in structure will no doubt occur to those skilled in the art, and are to be understood as forming a part of the invention insofar as they fall within the spirit and scope of the appended claims.

The invention is claimed as follows:

1. Piano mechanism comprising a key, means pivotally mounting said key, a vibratile tone generator mounted near said key, pivotally mounted hammer means comprising a butt and a striking head carried from said butt, said butt having a recessed portion and a bearing surface adjacent said recessed portion, an adjustment screw threaded through said butt and projecting therefrom adjacent said bearing surface and forming with said hearing surface a pocket, said butt having a recess on the 0pposite side thereof from the first mentioned recess and an adjustment screw threaded through said butt from the second mentioned recess to a position adjacent the first mentioned recess, a jack engageable with said pocket and having a cover thereon of variable thickness engaging said pocket, the adjustment screw threaded through said butt from the second mentioned recess engaging said cover of variable thickness for holding said jack in said pocket regardless of the thickness of said covering, and means operatively connecting said key and said jack for urging said jack against said bearing surface in said pocket for pivoting said hammer means upon manual pivoting of said key.

2. Piano mechanism as set forth in claim 1 wherein the tone generator is substantially horizontal, and wherein the hammer butt has a rest position below the horizontal, and pivots upwardly toward the horizontal position to carry the head into striking engagement with the tone generator.

3. Piano mechanism as set forth in claim 1 wherein the hammer striking head is mounted directly on the butt.

4. Piano mechanism comprising a key, means pivotally mounting said key, a vibratile tone generator mounted near, said key, pivotally mounted hammer means includinga butt and a striking head carried from said butt, said butt having a relieved area and a bearing surface adjacent said relieved area, an adjustment screw threaded through said butt and projecting therefrom adjacent said bearing surface and forming with said bearing surface a pocket, a second adjustment screw threaded through said butt to a position adjacent the relieved area, a jack engageable with said pocket, said second adjustment screw engaging said jack for holding said jack in said pocket, and means operatively connecting said key and said jack for urging said jack against said bearing surface in said pocket for pivoting said hammer means toward said tone generator upon manual pivoting of said key.

References Cited in the file of this patent UNITED STATES PATENTS 210,223 r Plass' Nov. 26, 1878 1,866,152" Cameron July 5, 1932 2,494,700 Gage Jan. 17, 1950 2,767,608 Miessner Oct. 23, 1956 2,806,398 Machalek Sept. 17,-1957- FOREIGN PATENTS 6,835 Great Britain May 13, 1835 15,039 Great Britain July 2, 1906

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