US2309278A - Piano action - Google Patents

Description

Jan. 26, 1943. c. scHULZ 2,309,278. v

PIANO ACTION Filed Feb. 5, 1941 Patented Jan. 26, 1943 UNITED STATES PATENT OFFICE PIANO ACTION Carl Schulze, Santa Barbara, Calif.

Application February 3, 1941, Serial No. 377,131

8 Claims.

This invention relates to a piano action. In most piano actions the hammer is driven forward by thrust exerted on its butt through a jack, and before the hammer head reaches the string the jack encounters a relatively fixed part or setoff which swings the jack out of contact with the shoulder against which it is exerting its thrust. The action of the setoff offers some resistance to the movement of the key and is an undesirable feature of most piano actions. A piano action having this setoff feature also has the disadvantage that repeat notes usually cannot be struck with great rapidity because the jack cannot quickly reassume its driving position on the shoulder of the butt.

The general object of this invention is to provide a piano action of simple construction which will operate without employing a positive setoif for the jack, and in such a way that in the cooperation of the jack and the driving shoulder on the hammer butt, the jack will gradually come into a position where its driving force on the hammer ceases. In other words, instead of providing a positive point of setoif my piano action operates in such a way that the advantageous relation or purchase of the jack on the driving shoulder becomes gradually less effective and finally disappears entirely, so that in this way no resistance is developed such as is occasioned by an ordinary setoff, as the key completes the down stroke.

A further object of the invention is to provide a piano action of simple construction in which the parts cooperate so as to allow time for the jack to reassurne an effective driving position with respect to the hammer butt, thereby enabling rapid repeat notes to be struck when this action is employed.

While the invention is applicable to any types of piano actions, in the present specification I have described it as applied to an upright or spinet type of piano, and as regards its application to this type of piano one of the objects of the invention is to produce an action which is very compact and which requires a relatively small horizontal depth from the forward edge of the keyboard to the piano strings; also to provide a construction in which the hammer heads are in a relatively low position with respect to the level of the keyboard. These features are highly desirable in spinet type piano actions.

As applied to an upright or a spinet type piano action, in practicing the invention the hammer is pivotally supported at one side of its butt so that the hammer shank extends upwardly in an ing the hammer to its position of rest.

inclined position in its normal position of rest. In the back-check position of the hammer the shank is substantially vertical. Associated with the hammer butt, means is provided for return- One of the objects of my invention is to provide in an action of this kind, means for retarding the acceleration of the return of the hammer toward its position of rest from the back-check position, and this cooperates with the jack in such a way as to enable the jack to return quickly to its effective driving relation with respect to the driving shoulder of the hammer when striking a repeat note.

Further objects of the invention will appear hereinafter.

The invention consists in the novel parts and combination of parts to be described hereinafter, all of which contribute to produce an efhcient piano action.

A preferred embodiment of the invention is described in the following specification, while the broad scope of the invention is pointed out in the appended claims.

In the drawing:

Figure 1 is a vertical section taken through a piano and illustrating my improved piano action in a state of rest, certain parts being broken away.

Figure 2 is a view similar to Figure 1 but showing the action in its back-check position.

Before proceeding to a more detailed description of the invention, it should be stated that in practicing the invention I provide a fulcrum or pivotal support for the key, and I pivotally support the jack on the key or a part of the key in such a position that when the key is struck the pivotal support for the jack will move in an are between the fulcrum of the key and the pivotal support for the hammer; in other words, along an arc in a direction to cross the line joining the rocking point of the key and the swinging axis of the hammer. The end of the jack thrusts against an inclined or curved driving shoulder on the butt of the hammer. By reason of this direction of movement of the pivotal support for'the jack, a com onent of the motion is developed which is lateral with respect to the axis of the hammer butt. Associated with the jack, yielding means is provided for maintaining the end of the jack in contact with the driving shoulder, but as the movement of the action progresses in a forward direction the inclination of the driving shoulder with relation to the end of the jack gradually increases until a point is reached when the jack can no longer effectively impart a driving force to the hammer butt. In other words, the end of the jack gradually slips off the shoulder during the forward stroke of the action. The eiiect of this of course is to give no feeling of resistance whatever to the finger which is depressing the key, as the drive ceases.

Also, when the hammer is in its back-check position after a key has been struck, a part which I associate with the jack engages the hammer butt in such a way as to resist or retard the return movement of the hammer to its position of rest. In this way time is allowed after the key is released from its down position to permit the jack to reassume an effective driving position on the shoulder for striking a repeat note. This renders the action capable of striking repeat notes very rapidly.

Referring now to Figures 1. and 2 which illustrate the action as employed in an upright, or a Spinet type of piano, I indicates the fulcrum board for the keys, such as the key 2, said board being provided with means for affording a pivotal or fulcrum support for the keys. In the present instance this is accomplished by providing the usual fulcrum pins, such as the pin 3, which preferably supports each key at an intermediate point on its length. At a point forward of the fulcrum pin 3, the body of the key is provided with a downward extension 4 which extends rearwardly under the fulcrum board, and this extension affords a pivotal support for a jack 5. In the present instance the jack is supported on an angle forming a bracket including a substantially vertical post with a tip i. The body of the jack is disposed in a substantially horizontal position with its end lying substantially against a felted driving shoulder 8 on a hammer butt 9. This felted shoulder 8 is inclined or curved upwardly toward the shank ID of the hammer. In the position of rest of the action, the hammer shank rests upon the hammer rail H.

The hammer is preferably pivotally supported on a pivot pin 12 which is disposed toward the front with respect to the axis of the hammer butt 9, and above the pivot 12 the hammer butt is preferably formed with a felted rest shoulder 13. The pivot I2 is supported on the hammer butt rail I4.

Suitable means is provided for urging the hammer to its position of rest. In the present instance I employ for this purpose a small coil spring (5, sitting on the upper face of the hammer butt rail thrusting against the end face of the butt 9.

Associated with the jack 5, means is provided for maintaining the end of the jack in contact with the driving shoulder 8 during the forward movement of the action. This means is preferably resilient or yielding, and preferably consists of a small coil spring which thrusts against the vertical face of the tip 1 of the angle bracket 8, and at its other end against the upwardly projecting heel ll of the jack.

When the key 2 is depressed, the pivot pin is of the jack moves along an are indicated by the line ill, the center of which is at the fulcrum point 29 on which the key rocks. The radius of this are is indicated by the letter R in Figure 1. When the key is struck, a thrust force is exerted through the j ck 5 against the felted driving shoulder 23, and the hammer immediately swings forward so as to strike the string 2! with the hammer head 22.

As the movement progresses it will be evident that the inclination of the felted shoulder 8 to the longitudinal axis of the body of the jack 5 will greatly increase, and the driving connection between the jack and the shoulder will become progressively less and less effective. During tlus movement the spring I6 of course maintains the contact between the end of the jack and the shoulder. Means is also provided for limiting the downward swinging movement of the jack 5 on its pivot l8, and in the present instance this consists of a cord or bridle 23, one end of which is attached to the heel I"! of the jack and the other end of which is attached to an adjusting pin 24 carried on the forward and under side of the extension 4. This bridle passes through openings 25 and 26 formed in the extension 4 for this purpose. This bridle regulates the point of release.

The bridle 23 wraps around this adjusting pin 24, and by tightening the pin the action of the jack in cooperating with the hammer butt can be nicely regulated.

Referring now to Figure 2, I provide the hammer butt with a back-check pad 2'! and a cooperating back-check pad 28 carried by the lower end of the extension 4 of the key. The backcheck pad 28 is preferably carried on a yielding bow 25 which tends to swing it toward the lower end of the extension 4 but can be adjusted outwardly by means of an adjusting screw 30 mounted in the lower end of the extension 4.

Figure 2 illustrates the parts of this action in substantially the relation they have in the backcheck position. In this position the bridle 23 is taut, and the end of the jack 5 is of course in an elevated position on the shoulder, substantially as shown, which is a relation in which the jack would be ineffective to impart a driving force to the hammer. Upon release of the key, of course, the pivotal support l3 for the jack 5 will swing down on the arc l9, enabling the end of the jack to ride down on the shoulder in an effective driving position to strike a repeat note. When this occurs, of course, the back- check pads 21 and 28 move out of contact with each other and the hammer will be urged to return to its position of rest by the spring Id. In accordance with my invention I provid means for retarding the backward acceleration of the hammer by the spring I 5, thereby givin time for the end of the jack to ride down on the driving shoulder 8. In order to accomplish this I prefer to provide resilient means in the form of a leaf spring 3|, the body of which is substantially straight and lies under the body of the jack 5; and which is provided with a tip 32 which normally rests on the rest shoulder l3 of the hammer butt. This leaf spring 3| has a U-shaped bow 33, one side of which may be attached to the angle bracket 6 substantially as shown. If desired, the body of this part 3| may be provided with a small lateral how 34 near its tip to give increased flexibility for the tip, and the adjacent face of the jack body may be provided with a clearance recess or notch 35.

The extension 4 preferably projects downwardly from the body of the key 2 at an angle of approximately 45", and this extension is preferably fonned with a slot 35 which extends upwardly into the same from its lower end. In this way I provide a relatively stout fork 3'! located toward the rear and a relatively thin and yielding fork 38 disposed toward the front. I provide means for adjusting the position of the relatively weaker fork 38, for which purpose I provide an adjusting screw 39 which is threaded in the fork 38 and provided at its forward end with a pad 40 to thrust against the adjacent face of the stout fork 31. The lower end of this yielding fork 38 is connected by a link or damper rod 4! to the lower end of the damper lever 42, so that this adjustment at 39 enables the position of the damper lever to be adjusted. Of course as soon as a key is depressed, the push rod 4| will rotate the damper lever (l2 and remove the damper 43 from the strings.

It will be noted that the extension 4 has a considerable portion of its mass located to the left of the fulcrum pin 3, and this about equals the mass of the extension which is located on the other side of the pin. For this reason the presence of this extension 4 does not unbalance the key to any appreciable extent. In practice I prefer to have the tail end 2 of the key shorter than the forward portion of the key, and if desired a counterweight, such as the counterweight 44, may be provided for attaining a very perfect balance of the key. If desired, a small spring 45 may be attached on the tail arm 2 which is in the form of a leaf spring thrustim against the under side of a rail lfi. This spring would of cours cooperate with the counterweight 44 to assist in returning the key 2 to its normal elevated position. This, spring 45 of course tends to overcome the inertia of the key and facilitates its quick return to normal position after the key has been struck.

t will be evident that this action is very accessiblefor regulating the adjustments. By lifting up on. the key 2, it can be removed readily from the piano case, carrying with it the jack and associated parts. Furthermore, if it is not desired to remove the key, the adjusting screws 24, 39 and Bil are all readily accessible from the front.

Many other embodiments of this invention may be resorted to without departing from the spirit of the invention.

What I claim is:

1. In a piano action, the combination of a hammer with a shank, and a butt having a driving shoulder, a pivotal support for the hammer butt, a key having a fulcrum support, and having a rigid extension below the keyboard, a jack having a pivotal support on the said extension and having its end located adjacent the driving shoulder so as to exert a thrust force against the shoulder to swing the hammer forward, the pivotal support for the jack being located rearwardly of the fulcrum support for the key so that when the key rocks in its down stroke the pivotal support for the jack swings upwardly about the fulcrum of the key and in a lateral direction with respect to the hammer pivot, and so as to approach the shank of the hammer, said driving shoulder being inclined away from the pivotal support of the jack and toward the shank of the hammer, said parts cooperating so that as the hammer swings forward on its pivotal support the inclination of the driving shoulder to the direction of thrust of the jack gradually increases, and gradually releases the hammer from the thrust force exerted by the jack.

2. In a piano action, the combination of a I hammer with a shank, and a butt having a .driving shoulder, a pivotal support for the hammer butt, a key having a fulcrum support, a jack having a pivotal support on the key and having its end located adjacent the driving shoulder so as to exert a thrust force against the shoulder to swing the hammer forward, the pivotal support for the jack being located so that when the key rocks in its down stroke the pivotal support for the jack swings about the fulcrum of the key in a lateral direction with respect to the hammer pivot, and so as to approach the shank of the hammer, said driving shoulder being inclined away from the pivotal support of the jack and toward the shank of the hammer, said parts cooperating So that as the hammer swings forward on its pivotal support the inclination of the driving shoulder to the direction of thrust of the jack gradually increases, and gradually releases the hammer from the thrust force exerted by the jack; and means independent of the hammer, associated with the key for adjustably limiting the pivotal movement of the jack toward the pivotal support of the butt, and thereby determining the point of release of th hammer butt from contact with the jack.

3. In a piano action, the combination of a hammer with a, shank, and a butt having a driving shoulder, a pivotal support for the hammer butt, a key having a fulcrum support, a jack having a pivotal support on the key and having its end located adjacent the driving shoulder so as to exert a thrust force against the shoulder to swing the hammer forward, the pivotal support for the jack being located so that when the key rocks in its down stroke the pivotal support for the jack swings about the fulcrum of the key in a lateral direction with respect to the hammer pivot, and so as to approach the shank of the hammer, said driving shoulder being inclined away from the pivotal support of the jack and toward the shank of the hammer, said parts cooperating so that as th hammer swings forward on its pivotal support the inclination of the driving shoulder to the direction of thrust of the jack gradually increases, and gradually releases the hammer from the thrust force exerted by the jack, means for yieldingly urging the jack in a direction to maintain contact between its end and the said driving shoulder while the action is in a state of rest, and means independent of the hammer and connected with the key for limiting the swinging movement of the jack on its pivot during the forward movement of the action to regulate the point at which the release of the butt from the driving force of the-jack takes place.

4. In a piano action, the combination of a hammer with a shank, and a butt having a driving shoulder, a pivotal support for the hammer butt, a key having a fulcrum support, a jack having a pivotal support on the key and having its end located adjacent the driving shoulder so as to exert a thrust force against the shoulder to swing the hammer forward, the pivotal support for the jack being located so that when the key rocks in its down stroke the pivotal support for the jack swings about the fulcrum of the key in a lateral direction with respect to the hammer pivot, and so as to approach the shank of the hammer, said driving shoulder being inclined away from the pivotal support of the jack and toward the shank of the hammer, said parts cooperating so that as the hammer swings forward on its pivotal support the inclination of the driving shoulder to the direction of thrust of the jack gradually increases, and gradually releases the hammer from the thrust force exerted by the jack, and means for adjusting the relation of the jack to the hammer butt, said hammer butt and said key having cooperating back-check means to hold the hammer in its back-check position on its r bound when the key is held down, a resilient counterbalance for the hammer associated with the butt, and for urging the hammer toward its position of rest, and a leaf spring associated with the jack for engaging the shoulder and exerting a yielding thrust against the jack to retard the back movement of the hammer from its back-check position when a repeat note is struck, thereby facilitating the movement of the end of the jack into driving position on the shoulder for striking a repeat note.

5. In an upright or spinet piano action, the combination of a key, means for supporting the :ey to rock about a fulcrum at an intermediate point on the length of the key, said key having an extension connected with the body of the key at a point forward of the fLLcrum and projecting rearwardly and under the fulcrum point, a hammer having a shank extending upwardly with its but-t disposed to the rear of the said extension, a pivotal connection for supporting the hammer butt, :1 jack pivotally supported on the extension, and extending over toward the hammer butt, said butt having a driving shoulder located above the pivotal support of the butt and inclining upwardly toward the harmner shank to receive the thrust of the jack, resilient means associated with the jack for urging the jack in a direction to depress its rear end, to press the jack toward the said shoulder during the movement of the hammer by the jack, said driving shoulder and said jack cooperating to cause the jack to slide out of contact with the driving shoulder during the forward movement of the hammer.

In an upright or spinet piano action, the combination of a key, means for supporting the key to rock about a fulcrum at an intermediate point on the length of the key, said key having an extension connected with the body of the key at a point forward of the fulcrum and projecting rearwardly and under the fulcrum point, a hammer having a shank extending upwardly wi h its butt disposed to the rear of the said extension, a pivotal connection for supporting the hammer butt, a jack pivotally supported on the extension, and extending over toward the hammer butt, said butt having a driving shoulder located above the pivotal support of the butt and inclining upwardly toward the hammer shank to receive the thrust of the jack, cooperating back check means carried by the hammer butt and by the said extension for holding the hammer in a back-check position when the key is struck and held down, resilient means for returning the hammer toward its position of rest, and means supported on the extension for resisting the return movement of the hammer by said resilient means, thereby facilitating the return of the jack to a position for driving the hammer butt in a repeat stroke immediately after the release of the key.

7. In an upright or spinet piano action, the combination of a key, means for supporting the key to rock about a fulcrum at an intermediate point on the length of the key, said key having an extension connected with the body of the key at a point forward of the fulcrum and projecting rearwardly and under the fulcrum point, a hammer having a shank extending upwardly with its butt disposed to the rear of the said extension, a pivotal connection for supporting the hammer butt, a jack pivotally supported on the extension, and extending over toward the hammer butt, said butt having a driving shoulder located above the pivotal support of the butt and inclining upwardly toward the hammer shank to receive the thrust of the jack, cooperating back-check means carried by the hammer butt and by the said extension for holding the hammer in its back-check position when the key is struck and held down, resilient means associated with the hammer butt for returning the hammer toward its position of rest, a leaf spring supported on the extension with its tip lying substantially against the driving shoulder, and located under the rear end of the jack for resisting and retarding the return movement of the hammer by its said resilient return means, thereby facilitating the return of the jack to a position for driving the hammer butt in a repeat stroke immediately after release of the key.

8. In an upright or spinet piano action, the combination of a key, means for supporting the key to rock about a fulcrum at an intermediate point on the length of the key, said key having an extension connection with the body of the key at a point forward of the fulcrum and projecting rearwardly and under the fulcrum point, a hammer having a shank extending upwardly with its butt disposed to the rear of the said extension, a pivotal connection for supporting the hammer butt, a jack pivotally supported on the extension, and extending over toward the hammer butt, said butt having a driving shoulder located above the pivotal support of the butt and inclining upwardly toward the hammer shank to receive the thrust of the jack and having a rest shoulder adjacent the end of the jack and against which the end of the jack substantially rests, said driving shoulder and said jack cooperating to cause the jack to slip rearwardly out of contact with the driving shoulder during the forward movement of the hammer.

CARL SCHULZE.

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