US2445512A - Piano action - Google Patents

Description

A. P. BROWN PIANO-ACTION Fild Jan. 9, 1946 INVENTOR: ALEXANDER R BROWN M A T TORNE) Patented July 20, 1948 PIANO ACTION Alexander P. Brown, Beechhurst, Long Island, N. Y.

Application January 9, 1946, Serial No. 639,922

2 Claims.

My invention relates to piano actions and, more particularly, to actions for spinets or upright pianos of restricted dimensions. An objects of my invention is to provide an action which can be inserted in a piano of a height not much exceeding the height of the keys.

In the prior art, this object has been attained by providing mechanisms connecting the key with an actuating element positioned at a lower level whereby the height of an action of otherwise more or less convention-a1 structure is reduced. Such devices are known as underslung actions. They have several severe disadvantages. The mechanism interposed between the key and the proper action increases the number of parts required, requires higher expenses, makes the structure more complicated, makes the proper adjustment more difficult and less reliable and results in a mushy touch and tones of poor quality.

Further objects of my invention are to avoid these drawbacks, to actuate the proper action by direct blow or stroke of the key, and, thereby, to obtain tones of perfect quality.

Other objects are to provide a jack and a hammer with lower ends hookingly engaging each other and positioned considerably lower than the key; to provide the hammer butt with an extension engaging a recess of the jack when the hammer rebounds whereby the jack acts as a back check; to provide a lever arm moving up when the key is struck and hinged to the upper end of the jack whereby the jack moves up when the key is struck; and to arrange the jack and the hammer in a narrow space located at the back side of the key.

A further object is to provide a damper which is withdrawn from the damping position by the jack at the end of a key stroke.

Still other objects are to arrange the hammer and the jack at a, short horizontal distance from each other; to facilitate, thereby, the proper engagement between these parts; to provide, thereby, for a small horizontal measure of the action and of the piano; and to provide a structure of the hammer rest which can be positioned in the narrow space between the hammer and the jack.

Still further objects are to provide means tripping the jack out of engagement with the hammer butt and into a position where the jack is ready to act as a back check; to provide a jack trip screw in a fixed position; and to provide means urging the jack into the engaging position.

Still other objects are to provide for insertion and removal of the action as a unit including the keys; and to provide a frame aflixed to the key bed and supporting fixed pivots of the action.

Still further objects are to reduce the number of parts, and to simplify the structure of a piano action of this type.

Still other objects and advantages will appear from the following description of an exemplifying embodiment of my invention, from the appended claims and from the accompanying drawing in which the figure shows a vertical, partially sectional side view of this embodiment.

It should be noted that, throughout this specification and claims, the front side is understood to be the side facing the performer or the left side in the drawing, and the back side to be the side facing the sound string or the right side in the drawing.

Referring to the drawing, numeral l indicates a key shown broken oil, the front part of this key being omitted. The key I can turn around a hinge 2 affixed, by a screw 60, to a key bed 3.

The key I can be operated either by the hand of a performer or by a pneumatic action which may move a wire 4 in vertical direction. The wire 4 may pass slidably through an opening of a block 5 aiiixed, by a screw 46, to the key bed 3 and may have an upper end provided with a head 6 contacting a padded lower surface 41 of the key I. In both kinds of operation, the back end of the key I moves upward when the key is struck.

The lever arm 1 has a fixed pivot 8 positioned over the key I and extends about horizontally over the back end of the key. The pivot 8 connects the arm I rotatably to a part 48 which is aifixed, by a screw 49, to a block 5% forming a part of the pianos stationary structure. The arm 1 carries an adjustable screw 9 contacting a padded upper surface 5| of the key I whereby the arm 1 is raised when the key is struck.

A jack If! is hinged to the arm I at a pivot point H positioned near the back end of the arm i and beyond the back end of the key I. A spring l2 has a fixed end [3 and a movable end [4 contacting the upper end of the jack in and urging the same in counter-clockwise direction around the pivot II and, at the same time, urging the jack and the arm 1 down.

A jack trip screw i5 is adjustably inserted in a fixed block I6 and has a padded surface 52 positioned over a projection ll of the jack l0 and contacting this projection at the end of a key stroke, whereby the jack is tripped or slightly turned around the pivot H in clockwise direction.

The jack I extends from the pivot I I' down in an oblique direction and has a lower end positioned considerably below the level of the key or of the key board. This lower end is provided with a back projection l8 for releasable engagement with a hammer as will be described later. The jack III has a V-shaped recess I9 at its front side which may be covered with leather 53 and serves as a back check as will be described later.

The arm I and the jack 10 may be made, for example, of plastics.

A hammer has a shank which, in the position of rest, is situated at a short distance from the jack I0 and at the back side thereof. A butt 2| is afilxed to the lower end of the shank 20 and has a recess 22 at the front side, facing the projection I8. This recess is releasably engaged by the projection I8 which pushes the butt up when the key is struck and the jack moves up, and pushes the butt '26 down when the key is released and the jack moves down. The surfaces of the recess 22 which are contacted by the projection 18 may be padded with felt layers 54 and 55, and a thin layer 23 of suitable protective material, for example, buckskin, may be placed over these felt layers and adjoining parts of the butts surface. The hammer butt 2| has a pivot or hinge 24 positioned farther to the back side than the recess 22. The stationary part 56 of the hinge 24 is affixed, by a screw 51, to a fixed block 25.

An extension or check 26 is affixed to the butt 2! and has a free end 21 shaped like a V and fitting the recess 19. Preferably, the extension 26 is made of a wire which has a flattened end 21 and may be bent for adjustment of the position of this end. The extension 26 is so adjusted that its V-shapcd end 21 wedgingly engages the recess I9 of the jack when the latter is tripped into its most forward position at the same time when the hammer rebounds.

A head 28 is aifixed to the uper end of the shank 2. When the hammer swings around the pivot 24 in clockwise direction, the head 28 hits a sounding string 29 in the position shown i dotted lines.

A hammer rest 30 forms a stop for counterclockwise movement of the hammer. In the position of rest, the shank 20 contacts a padded surface of the hammer rest 30. The latter is positioned in the narrow space between the shank 20 and the jack I6, and suitable clearance is left between the hammer rest and the jack. In order to make this arrangement possible, the structure of the hammer rest comprises, in contradistinction from the usual wooden bar or rail, a steel rail 3! which has a U-shaped cross-section having short legs bent into tight engagement with the pad of the hammer rest 30. This structure can be made sufficiently strong without requiring much space in the direction perpendicular to the shank 2D and makes it possible to arrange the jack IE! and the shank 20 at a short distance from each other.

A damper comprises a preferably vertically positioned arm 32, turnable around a fixed pivot 33, a head 34 and a wire 35 connecting the head 34 with the upper end of the arm 32. The pivot 33 connects the arm 32 rotatably to a part 58 which is affixed, by a screw 59, to the block 25.

A spring 36'has a fixed end and a movable end 37 urging the damper into contact with the string 29.

A tape or bridal strip 38 connects the damper with the jack whereby the damper is withdrawn 4 from the string 29 when the jack is tripped into its most forward position. Preferably, this connection is adjustable. For example, the front end of the bridal strip 38 terminates in a leather piece 39 hooked on a wire 40 which is affixed in a bore of the jack [0 and may be bent for adjustment.

The stationary parts of the action may be mounted on a common bracket 4|. For example, the block 25 carrying the pivots 24 and 33 of the hammer and the damper may be afiixed to the bracket 4| by means of a screw 42. Other stationary supports of the action may be afiixed to the same bracket in similar and well known manner, and the bracket 4| may be aiiixed to the main body or case of the piano in well known and separable manner. The case and some parts of the bracket M are omitted in the drawing. Several brackets 4| may be arranged. For example such brackets may be positioned at each end of a row of parallel actions. According to the invention, the key bed 3 is not directly connected to the case, but is mounted on the bracket 65. For example, the key bed 3 is affixed to this bracket by screws 314 and 43 whereby the keys and the key bed together with the other parts of the action form a unit which can be inserted in an upright piano in assembled and adjusted condition and can be taken out in assembled condition for re-adjustment or repair.

The described piano action operates as follows:

When the key I is struck, its back end drives the arm I up, raising the jack If! whereby the projection l8, engaging the recess 22 and pushing the upper surface thereof, turns the hammer around the pivot 24 into the position shown in dotted lines where the hammer head 28 strikes the string 29.

The jack trip screw I5 is so adjusted that, a short time before the key stroke is completed, the jack is turned in clockwise direction around the pivot l l sufficiently to withdraw the projection l8 and the lower end of the jack Hi from the butt recess 22. Simultaneously, the wire 40 pulls the bridal strip 38 and, thereby, turns the damper a little in counter-clockwise direction around the pivot 33 whereby the damper head 34 is withdrawn from the string 29. Then, the hammer, bein disengaged from the projection I8 of the jack, rebounds and is caught by the check end 21 as described before.

When the key I is released, it returns into the shown position of rest. At the same time, the spring l2 urges the jack Ii. and the arm "I back into the shown position. The jack is disengaged from the check, the projection l8 entering again the recess 22 and pushing the lower surface thereof down whereby the hammer is returned into the position shown in full lines.

I desire it understood that my invention is not confined to the particular embodiment shown and described, the same being merely illustrative, and that my invention may be carried out in other ways without departing from the spirit of my invention as it is obvious that the particular embodiment shown and described is only one of the many that may be employed to attain the objects of my invention.

Having described the nature of my invention, what I claim and desire to protect by Letters Patent is:

1. A piano action comprising a key having a back part movin up when the key is struck, a horizontal arm drivingly contacted by said key part and having a fixed pivot positioned over said key, a jack hinged to said arm and extending from said hinge down to a level considerably lower than said key, the lower part of said jack having a projection at its back side and a recess at its front side, and a hammer having a shank positioned at the back side of said jack and having a butt affixed to the lower end of said shank, said butt having a recess at its front side, and having a fixed pivot, and an extension affixed to said butt and having an end positioned in front of said jack, said extension end being engageable with said jack recess whereby said jack forms a back check for said hammer said butt recess and said projection engaging each other releasably.

2. A piano action comprising a key having a back part moving up when the key is struck, a horizontal arm drivingly contacted by said key part and having a fixed pivot positioned over said key, a jack hinged to said arm and extending from said hinge down to a level considerably lower than said key, the lower part of said jack havin a projection at its back side and a recess at its front side, a hammer having a shank positioned at the back side of said jack and having a butt affixed to the lower end of said shank, said butt having a recess at its front side, and having a fixed pivot, and an extension afiixed to said butt and having an end positioned in front of said jack, said extension end being engageable with said jack recess whereby said jack forms a back check for said hammer, said butt recess and said projection engaging each other releasably, a spring urging said jack down and into said engagement, and a fixed stop contacted by said jack at the end of a key stroke and tripping said jack out of said engagement.

ALEXANDER P. BROWN.

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