US2082548A - Action for keyboard instruments - Google Patents

Description

June 1, 1937. PAPE 2,082,548

ACTION FOR KEYBOARD INSTRUMENTS Filed F813- 4, I936 3 Sheets-Sheet 1 June 1, 1937. w. PAPE ACTION FOR KEYBOARD IRSTRUMENTYS Filed Feb. 4, 1936' 3 Sheets-Sheet 2 June 1, 1937. w. PAPE ACTION FOR KEYBOARD INSTRUMENTS Filed Feb. 4, 1936 k 3 Sheets-Sheet 5 Patented June 1, 1937 ACTION FOR KEYBOARD INSTRUMENTS Wilhelm Pape, Berlin-Wilmersdorf, Germany Application February 4, 1936, Serial No. 62,341 In Germany February 21, 1935 Claims. (Cl. 84-240) The invention relates to an'action for keyboard instruments such as pianos and grand pianos wherein the part, moved by the rear end of the key and acting on the hammer tumbler 5 or the hammer stem, also serves as a catch directly after striking.

Piano actions are known wherein the rear end of the key produces the hammer movement by an elastic intermediate member, usually a bent wire spring, serves as a catch for the hammer. In comparison with the actions at present usual with their numerous intermediate parts such devices have the advantage of great simplicity. They however do not afford a method of playing which is free from objection, mainly because the hammer, particularly when struck forcibly, can carry out vibrating natural movements by reason of its resilient support.

The subject of the invention solves the problem, with considerable simplification of the action, by. allowing the hammer stroke to be eiiected by a rigid part and stopping it directly after striking at a short distance from the string. This is effected by stopping the hammer tumbler or the end of the hammer stem corresponding thereto positively and rigidly between the pusher and a catch, and this stopping, without permitting of further deleterious vibrations of the hammer, becomes the more powerful the greater the pressure applied to the key.

A feature of the invention is that the key end which--for example in pianos-may be bent in the direction of height, acts either directly or through the medium of a rocking lever, by means of a rigid pusher thereon, on a part of the hammer tumbler or the hammer stem, and a part carried by the key end or the rocking lever serves as catch for an extension of the hammer tumbler or of the hammer stem acting in the 40 manner of a lever to the pivotal point of the hammer. Between the pusher and the extension there is thus effected, directly after striking, a firm clamping of the hammer tumbler or of the hammer stem. A further feature of the invention is the particular method of arranging the stop and catch surface on the hammer tumbler, the particular construction of the parts which'cooperate with one another for the purr pose of eliminating friction and wear and fur- O ther constructional developments of the separate parts which afford particular advantages.

According to the invention the height and depth of pianos and the height of grand pianos 55 can be reduced considerably. In spite of this the height of the keys and the position of the pedals remains normal.

The invention permits of the construction of very compact actions consisting of few parts, which afford easy playing, but with any method 5 of playing from the most powerful fortissimo to the softest and also the most complete tremolo so that even small instruments are equal in force and expression to large instruments.

In the accompanying drawings are shown by 10 way of example two forms of construction of the invention for a piano with vertical strings and a form of construction for a grand piano.

Fig. 1 shows a piano action with a struck key and Fig. 2 a piano action with a freely disposed 15 key.

Figs. 3 and 4 show a somewhat different form of construction under the same conditions.

Fig. 3 shows a modification of the form shown in Fig. 3. 20

the piano. 25 I Fig. 8 is a like showing of applicant's action.

In Figs. 1 and 2, l is the key-resting on its support, which key is in the present case provided with a downwardly extending bend 3 which in the present case is notched at 4. I is 30 the hammer tumbler pivotally mounted in the usual manner with the hammer tumbler spring 22. The downward bend 3 of the key is provided with a screw Ill, forming the pusher and having an arched head. Screw Ill can be ac- 35 curately adjusted as it is attached to bend 3 by screwing into a threaded hole in said bend. Screw I0 passes through a tail-like fork 9 which at the bottom terminates in the hammer tumbler cushion II. The head 8 of this screw strikes 40 against the hammer tumbler leather 2|, which is also arched, the arching of both parts being of such a shape that there is effected as smooth a rolling as possible to avoid sliding movement. Opposite the hammer tumbler cushion H there 45 is located on the key downward bend a counter surface I3 which is also covered with a cushion or leather and which can be adjusted by turning the small screw I2. On the end of this small screw there is mounted for this purpose a small plate l2 which carries the cushion or leather covering. In the lower""'extension of the key downward bend 3 there is provided a further screw l4 which can act on the part l5, covered'with cloth, of the damper IS. The damper rod 25 of the damper I 6 is pivotally mounted in the usual manner.

The method of operation of the device is as follows:

When the key, in the position of rest in Fig. 2, is struck the pusher head 8 strikes against the hammer tumbler leather 2| and throws the hammer head 5 into the position in Fig. 1. The hammer tumbler cushion ll then, however, strikes against the counter cushion or the catch l3 and the result of this is that after the striking there is effected a stopping in the swing of the hammer head 5. This actually strikes, in consequence of the elasticity located in the hammer tumbler, in the hammer stem and in the cushions, with a force which corresponds with the force of striking the key, against the string 8, but by means of the stop parts II and I3 the hammer head is held back with the utmost security somewhat from the string immediately after its recoil (Fig. 1) so that the correct striking of the string cannot in any way be deleteriously influenced. The head 8 of the pusher I0 holds the fork 9 always with certainty in connection with the key so that good impacts are also effected even in the case of rapid repit'ition movements of the keys. There is thus obtained also a very large modulation andnuance capability; the driving member may also consist of felt covered wood or metal or may in itself be springy. When depressing the key the screw H has simultaneously pressed forward the extension I! of the damper 25 which was caused by the known lifting of the damping tufts IS. The head of the screw l4 and the counter cushion on the arm 15 are so arranged relatively to one another and so shaped that between them there mainly occurs a rolling action and consequently only the smallest degree of wear.

As will be seen, a little play is provided between the nose projection 9 and the head of the pusher 8 so that a slight swinging of the hammer tumbler against the string is not prevented thereby. It will be seen and it is essential that the more powerful thekey I is depressed and therefore also the key downward bend 3 is endeavored to be pressed to the left the more powerful is also the stopping which is effected between the stops II and I3 whereby the hammer head or its upper felt 5 is prevented from resting on the string 6 for a long time in a deleterious and unintentional manner, of which it would necessarily prevent vibration. The stop 26, covered with felt or leather, supports the key at 3 in its possition of rest.

It is essential that with the pusher ID or its .head 8 in the position shown relatively to the hammer tumbler leather 2| these two parts may be so constructed that they roll upon one another during the striking of the key and as far as possible do not slide, whereby wear at these parts is reduced to a minimum in contrast with the previous push tongues with sliding movement. In addition it is essential that the lower extension ll of the hammer tumbler I, which has a considerable distance relatively to the axis of oscillation 21 of the hammer tumbler, may be so constructed that the parts ll, i3 bear against one another in an effective manner in order to prevent continuous contact of the upper felt 5 with the string 8.

This action acts in an excellent manner whether the key is struck softly or powerfully. The number 01' details relatively to the hitherto usual repetition action for. cottage pianos is reduced in a far-reaching manner.

In the modified form of construction in Figs. 3 and 4 there is also included an intermediate member or rocking lever ll between the downward bent portion 3 and the hammer tumbler 1, which is hingedly mounted at 21 and swings with the key when this is struck. The pusher 10, which influences the hammer tumbler l, is

adjustable in this part I1, and the key carries a separate stop screw 23 which strikes against a cushion I8 of this intermediate member Il. Opposite the cushion IB is located a cushion 20 on the catch 2|] and this forms the stop for the hammer tumbler tail or the hammer tumbler cushion H. The screw l4 for influencing the damper 25 is now located in this intermediate member ll.

Fig. 3' reproduces the form of construction of Fig. 3 with the modification that there is also provided a set screw 30 for the catch 20 of the hammer tumbler tail ii.

The grand piano action according to Figs. 5 and 6 is constructed as follows:

The key I rests in the known manner on the support 2 (in Figs. 5 and 6 the parts I and 2 are shown broken away). The rearmost end 40 of the key acts on the damper 4| so that the damping tufts 42 are withdrawn at the correct time.

43 is the hammer stem rest cushion bar to which a rotatable ievr u is hinged at 45. On this there acts a screw 46 of the key I, and the rocking lever 44 carries a further screw 41, the pusher, which can act on the roller 2| which consists in the known manner of best deer skin and is secured to the stem 5' of the hammer 5. This hammer stem carries a padded extension and this finds its abutment on the catch 5i, provided with felt or leather 53', which is secured to the hinged lever 44. Also in this case the catch 5i may be provided with a plate 52 so that a good possibility of adjustment is available by the screw shown. The two screws 46 and 41 are also in this case provided with arched smoothly polished heads and they may be constructed with surfaces with which they co-operate, as correct rolling surfaces so that wear, due to friction, cannot occur. The screws 23, in may also in this case be provided in the known manner with small holes so that they can be effectively adjusted and readjusted.

The method of operation oi this form is as follows:

When the key I is moved out of its rest position in Fig. 6 into the operative position in Fig. 5 the screw 46 drives the rocking lever 44 upwards, the pusher 41 of the latter in turn acting on the roller 49 and thus causes the hammer 5 to swing upwardly. The padded extension 50 -finds its limit at the accurately adjusted catch 5|. The operation is such that the upper felt 5 only remains in contact with the string 6 for a moment, whilst the elasticity of the hammer and of the entire driving device plays a part. Directly after the striking the hammer is thus located in the position shown in Fig. 5. During striking the damper tufts 42 are raised.

In the rest position the hammer stem rests on its rest cushion bar 43. The principal similarity of this grand piano action with the piano action in Figs. 3 and 4 will be seen readily.

Figs. 7 and 8 show the considerable economy and also the space dimensions obtained by the new action.

Fig. 7 shows by way of example the insertion 7;

of the piano action usual at the present time,

and

Fig. 8 the insertion of the new action. The piano shrinks considerably not only in the direction of height but also in the direction of depth.

In the case of a grand piano the proportions are similar. I

The new principle may also be applied to keys which are provided with upwardly bent portions,

10 meanwhile the bending downwards is the most important in connection with pianos.

In the case of pianos having crossed strings the action and keyboard must be adapted to the inclined position of the strings.

As particular advantagethere applies the considerable reduction of the axes of rotation subjected to wear.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is:

1. In a'strin'ged musical instrument of the type described, a key, a pivoted hammer having a head and a stem, operatively connecting means between said key and said hammer comprising regulable rigid means operated by said key for transmitting the movement of the key to the hammer in a direction substantially parallel to the movement of the hammer about its pivot in striking a string, and rigid means operated by said key cooperating with said motion transmitting means to hold said hammer stem in a position slightly spaced from the corresponding string. e

the hammer stem comprises a hammer nut with a curved bearing surface and the rigid means for transmitting the motion comprises a bolt, the head of which has *a curvedsurface contacting 4o said curved surface of the hammer nut, 'said surfaces being so constructed and arranged that 2. 'I'hedevice as claimed in claim 1, in which there is rolling contact between them throughout the transmission of motion between the key and the hammer.

3. The device as claimed in claim 1 in which the rigid means cooperating with the movement transmission means .to hold the hammer fixed comprises a tail piece on the hammer nut and a regulable stop on the key against which the tail piece abuts when the key has been operated.

4. The device as claimed in claim 1 in which there is a' cross-beam, a rest for said stem on said cross-beam and said means for transmitting movement, comprises a lever pivoted on said cross beam, a screw-bolt on said key contacting said lever on its lower side, a screw bolt on the upper side of said lever, contacting the under side of the stem, all of said contacting surfaces being curved and so constructed and arranged as to provide rolling contact during transmission of the motion from the key to the hammer.

5. The device as claimed in claim 1 in which there is a cross-beam, a rest for said stem on said cross-beam and said means for transmitting movement, comprises a lever pivoted on said cross beam, a screw-bolt on said key contacting said lever on its lower side, a screw bolt on the upper side of said lever, contacting the under side of the stem, all of said contacting surfaces being curved and so constructed and arranged as to,

provide rolling contact during transmission of the motion from the key to the hammer, a tail piece on the hammer stem, and an abutment on the lever, said abutment being in the path of the tail piece as the hammerhead moves into operative position, and the surfaces of contact of said abutment and said tail piece being perpendicular to said path whereby the hammer stem is held from movement in one direction by said screw bolt on said lever and from movement in the other direction by said abutment.

WILHELM PAPE.

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