US3899952A

US3899952A - Adaptor for common pianos

Info

Publication number: US3899952A
Application number: US481316A
Authority: US
Inventors: Lance Regan
Original assignee: Individual
Current assignee: Individual
Priority date: 1974-03-11
Filing date: 1974-06-20
Publication date: 1975-08-19
Anticipated expiration: 1992-08-19
Also published as: CA986340A

Abstract

The invention relates to musical instruments of the general class wherein a vibratile member - such as a wire or reed - is struck by a percussive means to produce a note. There is provided a method of controlling the return of the percussive means against a stop member, after striking the vibratile member, by providing inertial means which the percussive means strikes and to which the kinetic energy of the percussive means is transferred, thus eliminating rebound of the percussive means from the stop member. The invention has particular application to pianos, but is by no means restricted thereto.

Description

United States Patent [191 Regan 1 Aug. 19, 1975 [54] ADAPTOR FOR COMMON PIANOS 3,426,637 2/1969 Hartman 84/238 [76] Inventor: Lance Regan, l9l Vernon Ave.,

Kamloops, British Columbia Primary bxammer-Stephen .l. Tomsky Canada Assistant Examiner.lohn F. Gonzales Attorney, Agent, or FirmDennison, Dennison, Filedi June 20, 1974 Townshend & Meserole 21 Appl. No.2 481,316

[57] ABSTRACT [30] Foreign Application Priority Data The invention relates to musical instruments of the M H 1974 C 'da 1946 1 general class wherein a vibratile member such as a and wire or reed is struck by a percussive means to produce a note. There is provided a method of controlling 2% 5 84/236 i the return of the percussive means against a stop E 5 g 4/236 242 member, after striking the vibratile member, by pro- 84/253 viding inertial means which the percussive means strikes and to which the kinetic energy of the percussive means is transferred, thus eliminating rebound of [56] References Cited the percussive means from the stop member. The in- UNITED STATES PATENTS vention has particular application to pianos, but is by 165,304 7/1875 Carr 84/253 no means restricted thereto, 2,469,568 5/1949 Miessner 84/240 I 2,501,529 3 1950 Markley 84/240 16 Claims, 4 Drawing g r ADAPTOR FOR COMMON PIANOS This invention relates to pianos and similar instruments, wherein notes of various frequencies are produced by Striking vibratile members such as strings or wires and more particularly relates to a method of controlling the movement of the percussive means employed for such striking.

Various musical instruments are played bycausing'a percussive means (such as a hammer) to strike a vibratile member such as a taut string, wire or reed, and thus produce a note of a pitch determined by the dimensions, tension, etc. of the vibratile member. Examples of such instruments are the piano, harpsichord, clavichord, dulcimer, etc. Of the instruments of this general class, the most common is probably the piano, which uses a plurality of hammer mechanisms to strike taut wires. The mechanism includes a hammer head carried on a stem which is pivotally mounted so that the hammer head may be caused to strike the wire by rotation of the stem about its pivot mounting. The stem normally rests against a hammer rail with the hammer head remote from the wire, and remains in this position until the key associated therewith is depressed. Upon depression of the key, a mechanism associated therewith bears upon the stem and causes rapid rotation thereof so that the hammer head is moved to strike the wire and produce the desired note. The hammer head rebounds from the string and falls back under the weight of the action associated therewith until the stem strikes the hammer rail, the hammer head thus promptly clearing the wire and allowing the clean vibration thereof and production of the desired note.

Particularly for the playing repetitive notes upon the same key, it is extremely important that the stem be repositioned as quickly as possible after each strike of the hammer head so that the mechanism is able to immediately reactivate the stem, if required to do so. Unfortunately, the conventional key mechanism requires not only rapid but also accurate repositioning of the stem for repetition of the note. These requirements are not wholly satisfied in certain types of piano mechanism particularly in upright pianosf'The speed with which the hammer stem is returned to its original position causes the stem to impact the hammer rail with considerable force and rebound therefrom. As stated above, the conventional piano key mechanism requires that the hammer stem be accurately positioned before the mechanism is capable of activating same, and the aforementioned rebound condition seriously delays the stem from assuming such position. Thus, if the key is struck repetitively and in rapid succession, the hammer stern rebounds and does not have sufficient time to return fully and notes are missed.

An object of the present invention is to provide means for controlling and decelerating the return of the hammer stem against the hammer rail and thus greatly diminish or eliminate the rebound condition, which means may be readily applied to the percussive mem' ber of any instrument of general type described herein.

Thus, according to the present invention, there is provided, a musical instrument comprising a plurality of vibratile members capable of vibration to produce notes of selected frequencies, percussive means for each said vibratile member for causing vibration thereof, actuatingmeans for selectively moving each said percussive means from a rest position,'to strike a vibratile member associated therewith, return means for returning said percussive means to said rest position, a stop member for said percussive means in said rest position, and a control mechanism for said percussive means including inertial means movable in the direction of motionof said percussive means when struck thereby to absorb the kinetic energy of said percussive means moving towards said stop member and thereby exert a decelerative force upon said percussive means.

The invention will now be described further by way of example only and with reference to the accompanying drawings, wherein:

FIG. 1 is a side elevation of a structure according to one embodiment of the present invention;

FIG. 2 is -a perspective view of part of the structure shown in FIG. 1;

FIG. 3 is a side elevation of a detail of the embodiment shown in FIG. 1; and

FIG. 4 is a side elevation of a structure according to a further embodiment of the invention.

Referring now to the drawings, FIG. 1 shows a hammer head 10 supported by a stem 11 and provided with a hammer felt 12. The hammer stem is pivotally supported at its lower end by an action assembly (not shown) for causing the hammer to move quickly in the direction of the arrow A upon depression of the key associated therewith and to strike the appropriate wire. The weight of the action in conjunction with a resilient return mechanism (again not shown) associated with the stern causes the hammer to rebound and return quickly after striking the wire and move into abutment with the felt pad 13 located upon the hammer rail 14. These elements are quite conventional upon pianos of various types and need not be described further. As stated above, the hammer head must return quickly after striking of the wire in order that it does not inter fere with the clean vibration of the wire, and so that the hammer is repositioned for the next strike. However, the necessity for quick return gives rise to the problem of rebound. The hammer stem, returning quickly, strikes the felt pad 13 with considerable force, causing a tendency for the stem to rebound therefrom. Such rebound delays the proper repositioning of the lower end of the stem for subsequent action by the key mechanism thereupon, thus detrimentally affecting the facility of the piano for playing rapid repetitive notes.

In the rebound control mechanism shown in FIG. 1, the hammer rail 14 is provided at intervals therealong with slotted base clamps 15. Each base clamp 15 is provided at its rear edge, remote from the hammer rail 14, with an upstanding flange portion 16 (see also FIG. 2). Supported by the base clamps l5 and abutting the flange portions 16 there is provided a supportmember 17 having, glued to the surface thereof facing the rear of the hammer rail 14, a felt strip 18 which extends over the length'of the member 17. Each flange portion 16 is slotted as at 19, and the support member is fastened to each of the flange portions 16 by means of a screw 19a passing'through the slot 19 and threadedly engaged with the support member. Thus, theheight of each end of the support member may be adjusted by loosening the screw 19a and sliding same in the slot .19 to the desired position, and tightening the screw to securely locate the support member. The purpose of this facility will hereinafter become apparent.

"The support member 17 is-provided with a tongue 21 extending the length thereof, by means of which the respective rebound control mechanisms for the individual hammer stems may be affixed to the support member at appropriately spaced locations therealong, corresponding to the spacing of the hammer stems. Each rebound control mechanism comprises a holder 22 having a groove 23 dimensioned to engage with the tongue 21 on the support member 17. The holder overhangs the felt strip 18 on the face of the support mem ber 17, and a pin 24 is pivotally conected to this overhanging portion of the holder.

The lower end of the pin 24 is somewhat tapered as at 24a and the upper end is provided with a felt pad 25 on the surface thereof facing the rear portion b of the hammer head 10. An adjustment fine screw 20 is provided for each pin 24, such screw passing through and threadedly engaged with the support member and bearing upon the lower end 24a via the felt covering strip 18. As may be clearly seen in FIG. 1, the position of pin 24 is so adjusted by its associated screw 20 that the hammer head rear surface 10b is just clear of the felt pad 25, when the hammer stem 11 is at rest against the pad 13, the upper end of the pin 24 being biased towards the hammer head by means of a springy strip of metal 26, attached at one end to the holder 22 and abutting the rear surface of the pin 24.

The mechanism operates as follows. When the key associated with a particular hammer is depressed, the hammer head moves quickly in the direction of the arrow A, as explained above. When the hammer returns, the stem 11 firstly contracts the surface of the felt pad 13. The adjustment screw 20 is carefully preset so that as the further motion of the stem 11 starts to compress the felt pad 13, the rear portion 10b strikes the pin 24. The kinetic energy of the hammer is now transferred to the pin 24, which moves back against the bias of the spring 26, and the motion of the hammer and stem assumes a position of rest against the pad 13. However, the transfer of energy to the pin 24 completely eliminates any rebound of the stem from the pad 13 or hammer rail 14. The operation is completed by repositioning of the pin 24 under the influence of the spring 26.

To prepare the mechanism for proper functioning thereof, various adjustments are provided. The vertical position of each pin 24 and its associated pad 25 may be set by adjusting the height of the support member 17, in the manner described above. The extent to which the pin 24 is allowed to pivot under the influence of the spring 26 is determined by coarsely adjusting the position of the base clamp 15 and thus the active rebound control mechanism relative to the hammer rail 14. The fine adjustment is then made by means of the screw and felt strip 18 covering same, which effectively functions as a stop for the lower end 240 of the pin. In an alternative embodiment, the continuous strip 18 may be replaced by a series of individual felt discs one for each pin each disc carried upon the end of a flat end screw, passing through and threadedly engaged with the support member 17. Such an arrangement is shown in FIG. 3, which shows the support member 17, the lower end 24a of the pin 24 and an adjustment screw 27 having a felt disc 28 thereon. Thus, the

extent of movement of the pin 24 under the influence of the spring 26 may be finely adjusted by appropriate positioning of the screw 27 and felt disc 28. The adjustment of the gap between the hammer head 1012 at rest, and the felt silencer pad 25 is critical. If the gap is too wide, the compression of the felt pad 13 is too great, and a rebound force is generated thereby which would defeat the object of the invention. If the gap is too small, the hammer head strikes the felt pad 25 too soon and, again, a rebound action is created.

The coarse adjustment means for positioning of the support member 17 may best be seen in FIG. 2, which shows a slot 29 formed at one end of the base clamp 15, and extending transversely thereof. A screw 30 is provided passing through the slot 29 and freely slidable therein, the screw 30 threadedly engaged with the hammer rail 14. Thus, the support member 17 may be moved back and forth upon the base clamp 15 for positioning thereof, and the screw 30 then tightened to securely clamp the support member 17 in the desired location. The arrangement of the slot and crew means just described is also provided at intervals along support member 17, so that various regions of the support member 17 may be independently positioned.

Thus, by a combination of these adjustment means, the support member 17 with the rebound eliminator mechanism may be positioned to effectively check and control the return of the hammer head and stem after striking of the note, and thereby optimize the proper positioning at the stem for reactivation by the piano key mechanism.

Turning now to FIG. 4, there is shown a further embodiment of the invention, comprising a tubular member 131 having a plunger 132 extending from one end thereof. The bore of the tubular member 131 is threaded at its opposite end, and a screw 133 is threadedly engaged therewith, the head 134 of the screw 133 being accessible exteriorly of the tubular member. Interposed between the end of the screw 133 and the plunger 132 is a compression spring 135.

The tubular member 131 is provided with a threaded orifice 136 extending therethrough from the exterior to the bore. A screw 137 is threadedly engaged within the orifice and may be screwed down to its full limit with the screw head 138 abutting the exterior surface of the member 131. The screw 137 is provided with a short extension 139 which protrudes slightly into the bore of the member 131 when the screw is fully tightened, as clearly shown in FIG. 4. The plunger 132 has a groove 140 formed therein, which extends for ashort distance along the surface of the plunger and parallel to the axis thereof.

The plunger is firstly inserted into the tubular member against the compression of the spring 135, the screw 138 being withdrawn slightly so that the extension 139 is retracted within the threaded hole 136. The groove 140 is positioned beneath the screw extension 139 and the screw 138 is then tightened down so that the extension 139 enters within the confines of the slot 140. It is essential that the screw 138 be so dimensioned that the extension 139 does not impede the free sliding of the plunger 132 within the tubular member 131. The plunger, being under the influence of the compression spring is urged outwardly of the tubular member 131 and such outward movement is limited by the abutment of the end wall a of the .slot 140 upon the screw extension 139, thus preventing the plunger from being completely ejectedor otherwise free to escape from the tubular member.

The exterior end of the plunger 132 is provided with a felt disc 14], and the tubular member is so positioned and angled that the hammer head 10, during the last portion of its return stroke towards the hammer rail 14 i.e., during compression of the hammer rail felt 13, engages the felt disc 141 and pushes the plunger 132 inwardly of the tubular member against the outward bias exerted by the compression spring 135. Thus, the kinetic energy of the moving hammer is absorbed by the plunger 132, and further motion of the hammer is effectively halted. Fine adjustment of the normal positioning of the plunger, i.e., with the felt disc 141 just separated from the hammer rear portion is set by adjustment of the compression spring 135, which, in turn, is adjusted by means of the screw 133.

In similar fashion to the arrangement of FlGS. l to 3 inclusive, the entire rebound control assembly is mounted upon a slotted base clamp 150, which is fastened by means of a screw 151 to the hammer rail 14. Thus, the hechanism may be coarsely positioned by loosening of the screw 151, appropriately positioning the base clamp 150, and subsequently tightening the screw 151. Vertical adjustment of the position of the plunger 132 is provided by means of a slotted first support bracket 153 fastened to the bracket 152 and a second support bracket 153 fastened to the bracket 152 and depending from the tubular member 131. The

support brackets

152 and 153 are fastened together by means of a screw 154 passing through a hole in the bracket 153 and through the slot of the bracket 152 and threadedly engaged by a nut 155. The slot configuration of the bracket 152 permits upwards and downwards adjustment of the position of the plunger 132 relative to the hammer head 10, to ensure that the hammer head engages the plunger squarely in its return stroke.

Thus, I have provided a simple and efficient mechanism for controlling the rebound of a hammer or similar percussive member in an instrument of the general class described, which mechanism is by no means restricted to the examples given above. In alternative ar rangements, the return means for the pin 24 or plunger 132, may be other than a spring for example, a resilient cushioning meterial such as polyurethane foam of predetermined density and thickness to provide the desired degree of resilience.

The mass or weight of the material used for the inertial member i.e., the pin 24 of FIG. 1 and the plunger 132 of FIG. 4 is critical to the particular application to which the device is applied. For example, regular steel has been found to be quite satisfactory for various common upright pianos, but in certain types of pianos or other instruments, the material is desirably of different mass for example, lead or aluminum. The selection of material and the mass thereof depends mainly upon the amount of energy to be dissipated, and may readily be determined by experimentation or calculation for particular applications by one skilled in the art.

Furthermore, it is stressed that the precise nature of the instrument or the vibratile member employed therein is in no way limiting upon the scope of the present invention, which is applicable to any instrument which employs mechanically actuated percussive means and wherein the rate of return of said percussive means to the rest position requires to be controlled.

We claim:

1. A musical instrument comprising a plurality of vibratile members capable of vibration to produce notes of selected frequencies. percussive means for each said vibratile member for causing vibration thereof, actuating means for selectively moving each said percussive means from a rest position, to strike a vibratile member associated therewith, return means for returning said percussive means to said rest position, a stop member for said percussive means in said rest position, and a control mechanism for said percussive means including inertial means movable in the direction of motion of said percussive means towards said stop member and active upon said percussive means when struck thereby to absorb the kinetic energy of said percussive means moving towards said stop member and thereby exert a decelerative force upon said percussive means said stop member having a surface of resiliently deformable material which said percussive means abuts in said rest position thereof, and said inertial means being located for striking by said percussive means moving towards said stop member substantially at the moment of initial contact of said percussive means with said resiliently deformable material.

2. A musical instrument as claimed in claim 1, wherein said inertial means comprises a pivotally mounted member.

3. A musical instrument as claimed in claim 1, wherein each said percussive means comprises a striking member for striking said vibratile member and said control mechanism is directly active upon said striking member.

4. A musical instrument as claimed in claim 1, wherein each said percussive means comprises a hammer head for striking said vibratile member and a stem upon which said hammer head is carried, said stem being rotatable about a transverse axis thereof spaced from said hammer head, said actuating means capable of rotating said stem about said axis to cause said hammer head to strike said vibratile member and said return means urging said stem into abutment with said stop member, and said control mechanism being directly active upon said hammer head.

5. A musical instrument as claimed in claim 1, wherein said inertial means comprises a pivotally mounted member provided with resiliently deformable means biasing said member towards said percussive means. 7

6. A musical instrument as claimed in claim 1, wherein said inertial means comprises an energy absorbing mass pivotally mounted for rotation about a transverse axis thereof substantially normal to the plane containing said movement of said percussive means, said mass being located in a rest position thereof in the path of said percussive means for en gagement of said percussive means therewith upon return of said percussive means to its rest position to cause rotation of said mass in a first direction about said axis, and a leaf spring engaging a region of said mass remote from said axis and urging rotation of said mass in a second direction opposite to said first direction to return said mass to said rest position.

7. A musical instrument as claimed in claim 1, wherein said inertial means is a piston slidably located within a cylinder.

8. A musical instrument as claimed in claim 1, comprising a tubular member having a closed end and an open end, said open end having a plunger forming said inertial means extending from and slidable in said tubular member, a compression spring located between said plunger and the closed end of said tubular member and biasing said tubular member into a rest position thereof, said plunger in its rest position located in the path of said percussive means for striking of said percussive means thereupon, as said percussive means moves against said stop member, causing transfer of kinetic energy from said percussive means to said plunger and depression of said plunger within said tubular member against the bias of said compression spring to exert a decelerative force upon said percussive means.

9. A musical instrument as claimed in claim 8, said instrument being a piano.

10. A musical instrument as claimed in claim 8, wherein the closed end of said tubular member .is formed by a screw, threadedly engaged within the bore of said tubular member, the head of said screw accessible from the exterior of said tubular member to permit positioning of said screw within said tubular member and adjustment of the pressure of said spring upon said plunger.

11. A musical instrument comprising:

a plurality of vibratile members capable of vibration to produce notes of selected frequencies;

percussive means for each said vibratile member,

each said percussive means comprising a hammer head for striking a vibratile member and a stem upon which said hammer head is carried, said stem being rotatable about a transverse axis thereof spaced from said hammer head;

actuating means for each said percussive means comprising means for selectively turning said stem about said transverse axis thereof to cause said hammer to strike said vibratile member associated therewith;

return means for urging each said stem into abutment with a stop member, said stop member having a surface layer of resiliently deformable material which said stem abuts in a rest position thereof; and

a control mechanism for each said hammer head and directly active thereupon, each said control mechanism comprising an energy absorbing mass pivotally mounted for rotation about a transverse axis thereof substantially normal to the plane containing tuning movement of said hammer head and stem, said mass being located in a rest position thereof for striking by said hammer head moving towards said stop member substantially at the mo ment of initial contact of said stem with said surface layer of resiliently deformable material of the stop member to cause transfer of kinetic energy from said hammer head to said mass and rotation of said mass in a first direction about said axis thereof, and a leaf spring secured at one end thereof with its opposite end engaging a region of said mass remote from said axis and urging rotation of said mass in a second direction opposite to said first direction to return said mass to its rest position as aforesaid.

12. A musical instrument as claimed in claim 11, said instrument being a piano.

13. A musical instrument as claimed in claim 1], further comprising a second stop member for said mass, adapted to limit rotational movement of said mass in said second direction.

14. A musical instrument as claimed in claim 11, further comprising a second stop member for said mass, adapted to limit rotational movement of said mass in said second direction, and adjustment means for adjustably positioning said second stop member relative to said axis to selectively limit the rotational movement of said mass in said second direction.

15. A musical instrument as claimed in claim 11, further comprising a second stop member for said mass, adapted to limit rotational movement of said mass in said second direction, first adjustment means for adjustably positioning said second stop member relative to said axis to selectively limit the rotational movement of said mass in said second direction, and second adjustment means providing two dimensional adjustability of the position of said mass relative to said firstnamed stop member in the plane of rotation of said mass about said axis.

16. A musical instrument comprising:

percussive means for each vibratile member, each said percussive means comprising a hammer head for striking a vibratile member and a stem upon which said hammer head is carried, said stem being rotatable about a transverse axis thereof spaced from said hammer head;

actuating means for each said percussive means comprising means for selectively turning the stem of said percussive means about said transverse axis thereof to cause said hammer to strike said vibratile member associated therewith;

return means for urging each said stern into abutment with a stop member; and

a control mechanism for each said hammer head and directly active thereupon, each said control mechanism comprising a tubular member having a closed end and an open end, said open end having a plunger extending therefrom and slidable in said tubular member, said plunger located in a rest position thereof for striking by said hammer head moving towards said stop member substantially at the moment of initial contact of said stem with said surface layer of resiliently deformable material of the stop member to cause transfer of kinetic energy from said hammer head to said plunger and movement of said plunger inwardly of said tubular member, and a compression spring located between said plunger and the closed end of said tubular member to return said plunger to its rest position as aforesaid.

Claims

1. A musical instrument comprising a plurality of vibratile members capable of vibration to produce notes of selected frequencies, percussive means for each said vibratile member for causing vibration thereof, actuating means for selectively moving each said percussive means from a rest position, to strike a vibratile member associated therewith, return means for returning said percussive means to said rest position, a stop member for said percussive means in said rest position, and a control mechanism for said percussive means including inertial means movable in the direction of motion of said percussive means towards said stop member and active upon said percussive means when struck thereby to absorb the kinetic energy of said percussive means moving towards said stop member and thereby exert a decelerative force upon said percussive means said stop member having a surface of resiliently deformable material which said percussive means abuts in said rest position thereof, and said inertial means being located for striking by said percussive means moving towards said stop member substantially at the moment of initial contact of said percussive means with said resiliently deformable material.

5. A musical instrument as claimed in claim 1, wherein said inertial means comprises a pivotally mounted member provided with resiliently deformable means biasing said member towards said percussive means.

6. A musical instrument as claimed in claim 1, wherein said inertial means comprises an energy absorbing mass pivotally mounted for rotation about a transverse axis thereof substantially normal to the plane containing said movement of said percussive means, said mass being located in a rest position thereof in the path of said percussive means for engagement of said percussive means therewith upon return of said percussive means to its rest position to cause rotation of said mass in a first direction about said axis, and a leaf spring engaging a region of said mass remote from said axis and urging rotation of said mass in a second direction opposite to said first direction to return said mass to said rest position.

9. A musical instrument as claimed in claim 18, said instrument being a piano.

10. A musical instrument as claimed in claim 18, wherein the closed end of said tubular member is formed by a screw, threadedly engaged within the bore of said tubular member, the head of said screw accessible from the exterior of said tubular member to permit positioning of said screw within said tubular member and adjustment of the pressure of said spring upon said plunger.

11. A musical instrument comprising: a plurality of vibratile members capable of vibration to produce notes of selected frequencies; percussive means for each said vibratile member, each said percussive means comprising a hammer head for striking a vibratile member and a stem upon which said hammer head is carried, said stem being rotatable about a transverse axis thereof spaced from said hammer head; actuating means for each said percussive means comprising means for selectively turning said stem about said transverse axis thereof to cause said hammer to strike said vibratile member associated therewith; return means for urging each said stem into abutment with a stop member, said stop member having a surface layer of resiliently deformable material which said stem abuts in a rest position thereof; and a control mechanism for each said hammer head and directly active thereupon, each said control mechanism comprising an energy absorbing mass pivotally mounted for rotation about a transverse axis thereof substantially normal to the plane containing tuning movement of said hammer head and stem, said mass being located in a rest position thereof for striking by said hammer head moving toWards said stop member substantially at the moment of initial contact of said stem with said surface layer of resiliently deformable material of the stop member to cause transfer of kinetic energy from said hammer head to said mass and rotation of said mass in a first direction about said axis thereof, and a leaf spring secured at one end thereof with its opposite end engaging a region of said mass remote from said axis and urging rotation of said mass in a second direction opposite to said first direction to return said mass to its rest position as aforesaid.

12. A musical instrument as claimed in claim 11, said instrument being a piano.

13. A musical instrument as claimed in claim 11, further comprising a second stop member for said mass, adapted to limit rotational movement of said mass in said second direction.

15. A musical instrument as claimed in claim 11, further comprising a second stop member for said mass, adapted to limit rotational movement of said mass in said second direction, first adjustment means for adjustably positioning said second stop member relative to said axis to selectively limit the rotational movement of said mass in said second direction, and second adjustment means providing two dimensional adjustability of the position of said mass relative to said first-named stop member in the plane of rotation of said mass about said axis.

16. A musical instrument comprising: a plurality of vibratile members capable of vibration to produce notes of selected frequencies; percussive means for each vibratile member, each said percussive means comprising a hammer head for striking a vibratile member and a stem upon which said hammer head is carried, said stem being rotatable about a transverse axis thereof spaced from said hammer head; actuating means for each said percussive means comprising means for selectively turning the stem of said percussive means about said transverse axis thereof to cause said hammer to strike said vibratile member associated therewith; return means for urging each said stem into abutment with a stop member; and a control mechanism for each said hammer head and directly active thereupon, each said control mechanism comprising a tubular member having a closed end and an open end, said open end having a plunger extending therefrom and slidable in said tubular member, said plunger located in a rest position thereof for striking by said hammer head moving towards said stop member substantially at the moment of initial contact of said stem with said surface layer of resiliently deformable material of the stop member to cause transfer of kinetic energy from said hammer head to said plunger and movement of said plunger inwardly of said tubular member, and a compression spring located between said plunger and the closed end of said tubular member to return said plunger to its rest position as aforesaid.