US2502861A

US2502861A - Striking and damping mechanism for pianos

Info

Publication number: US2502861A
Application number: US676269A
Authority: US
Inventors: Linderoth Hans Gunnar
Original assignee: Individual
Current assignee: Individual
Priority date: 1946-06-12
Filing date: 1946-06-12
Publication date: 1950-04-04
Anticipated expiration: 1967-04-04

Description

April 4, 1950 H. G. LINDEROTH STRIKING AND DAVIPING MECHANISM FOR PIANOS Filed June 12, 1946 Fig- I N VEN TOR. HAM: Com/AK .L/mmam A TTORNEY Patented Apr. 4, 1950 UNITED STATES PATENT OFFICE STRIKING AND DAMPING MECHANISM FOR PIANOS 11 Claims. 1

This invention relates to piano actions and particularly to the striking and damping mechanisms thereof.

Piano actions as heretofore constructed have involved complicated mechanism controlling the operation of the hammers and dampers from the keyboard, this mechanism being difiicult and expensive to make and install. The object of this invention is to provide a novel control mechanism which requires fewer parts, is relatively easy and inexpensive to construct and assemble, has an eilicient, positive action and requires relatively few adjustments of interrelated parts.

In the accompanying drawing, which illustrates a preferred form of striking and damping mechanism of the invention:

Fig. 1 is a view partly in vertical section, partly in side elevation, of the mechanism embodied in an upright type piano, showing in dotted lines an actuated position of certain parts;

Fig. 2 is detail elevation view of part of the mechanism shown in Fig. 1.

Referring to Fig. 1 of the drawing, the mechanism as shown comprises a support rail l extending the full length of the piano between the keyboard keys l2 and the strings l4. Rail I0 is provided along its upper edge adjacent the keyboard with a longitudinal groove l6 and in its end surface adjacent the strings with a second longitudinal groove IS, the grooves i6 and I8 extending the full length of the rail between the keyboard and the strings. Grooves I6 and 8 are, as shown, provided with undercut ends curved away from the center line of the groove and forming a restricted entrance throat or slot for the groove in the face of the rail.

The dampers 2d are each provided with the usual damper tip 22 and with a base 24 within which is anchored one end of a curved spring clip 26. Clip 26 is provided with a curvature generally conforming to that of groove [8 but of somewhat larger diameter and is adapted to be contracted by pressing its free end toward its anchored end for insertion through the restricted throat of groove it, the clip then expanding to fit tightly against the walls of the groove with the free and anchored ends protruding through the throat as shown in the drawing. The clip is formed of a flat, resilient strip providing a substantial bearing surface frictionally engaging the walls of the groove. Further, the clip is so formed and connected to the base of the damper that, when seated in groove iii, it resiliently supports and urges the damper to its normal position shown in full lines in Fig. 1 in which the damper base 24 is supported outwardly and free of rail ID on the end of clip 26, with the damper shaft inclined rearwardly and its tip 22 in damping engagement with the corresponding string I 4.

The hammer 23 is provided with the usual striking tip 30 and with a base 32 in which is anchored one end of a spring clip 34 similar to the clip 26 and like the latter adapted to be seated under pressure within the corresponding groove 16, with the anchored and free ends protruding from the groove to support the hammer base above and. free of rail in. Clip 34 is so constructed that when seated in groove l6, its protruding end attached to the hammer resiliently urges the hammer to a normal position shown in full lines in Fig. 1 in which the hammer shaft is inclined forwardly toward the keyboard and its tip 30 is away from the corresponding string l4.

An actuating cord 36 of nylon or the like, Spun, braided or plain, is afiixed at one end to damper 20 near its base 24, extends forwardly through a slot 38 in clip 34 below hammer base 32 and upwardly about the curved forward side of said base to the corresponding key 12 where its opposite end is wound on a take-up spindle 4U rotatably mounted on the'inner end of the key, the string extending downwardly through a slot 42 in the key. The base 32 of hammer 30 is provided, on the side engaged by cord 36 with projecting ribs 44 (Fig. 2) forming between them a track for the cord, these ribs maintaining the cord in constant engagement with the curved side of the base.

When key i2 is depressed about its pivot, the lifting of its inner end exerts a longitudinal pull on cord 36, causing damper 20 to rock forwardly on spring clip 26, the end of the clip attached to the damper flexing beneath the forward shoulder 46 formed by the restricted throat of groove l8. The damper is thus brought to its dotted line position of Fig. 1 in which its base 24 is cushioned against a felt 48 secured to the contiguous rear edge of rail l0 above groove I8 and the tip 22 is withdrawn from the string I4. Cord 36 is also tensioned against the curved surface of base 32 of hammer 28 between ribs 44 exerting a rearward pressure on the base which causes the hammer to rock rearwardly on spring clip 34, the clip flexing beneath the rear shoulder 59 formed by the restricted throat of groove l6.

This brings hammer 28 to the dotted line position of Fig. 1 in which its shaft is inclined rearwardly and its tip 30 is close to the string l4.

From this position the rearward momentum of the hammer carries it further rearwardly so that the tip strikes the string M which stops the rearward motion of the hammer and permits the hammer to rebound immediately, under the pressure of spring 34, to its dotted line position away from the string, in which position it is stopped by the tension of cord 36 and is held thereby against the pressure of the spring until the pressure on key 12 is released permitting the parts to return to their full line normal positions with the damper engaging and damping the string. To insure that the damper is fully released from the string l4 before the string is struck by the hammer, its spring 26 is made somewhat weaker than hammer spring 34 so that the tensioning of cord 36 preferentially flexes spring .28 moving the damper to its rearward position before completely actuating hammer 28.

My novel mechanism, as hereinabove described, is accurate and effective, yet relatively easyand inexpensive to construct, assemble andmaintain in adjustment, eliminating numerous parts of the standard mechanism heretofore employed such as the regulatingand spring rails, the whip and whip lifter, the abstract, the fly, the back check,

the catcher, etc.

While I prefer to anchor the cord 36 to the damper, this is not essential. It may, for example, be attached to rail l!) between the hammer and the strings. In such case the damper may be connected to the key by a separate cord or maybe connected to the hammer by a second cord or by leverage so arranged that forward movement of the hammer causes retraction of the damper. Also, the co-operating groove and clip arrangement shown for attaching the hammer and damper supporting springs to the rail, while preferable, is not essential, as the springs may be fastened to the rail in any suitable manner. As will be understood, therefore, these and other changes in the preferred illustrated embodiment of the invention may be made within the scope of the invention, as set forth in the appended claims.

I claim:

1. In a striking and damping mechanism for pianos, a hammer, a hammer support adjacent the piano strings having a groove therein, and a spring mounting said hammer on said support and resiliently supporting said hammer in spaced relation to said support in a normal position spaced from said strings, said spring being secured to said support by frictional engagement of the main body thereof with the walls of said groove and being yieldable to permit rocking of said ham-mer into striking engagement with oneof said strings.

2. In a striking and damping mechanism for pianos, a hammer, a hammer support adjacent the piano strings, a spring mounting said hammer on said support and resiliently supporting said hammer in spaced relation to said support in a normal position spaced from said strings, said spring being yieldable to permit rocking of said hammer into striking engagement with one of said strings, and means incapable of resisting longitudinally applied compressional forces operatively connecting one of the'keys of the piano keyboard to said hammer and operative on depression of said key to rock said hammer against the resistance of said spring into striking engagement with one of said strings while leaving the hammer free to rebound away from said string under-thepressure of said spring.

3. In a striking and damping mechanism for pianos, a hammer, a hammer support adjacent the piano strings, means mounting said hammer on said support for rocking to and from a position of striking engagement with one of said string-s, said mounting means including a spring yieldably resisting rocking of said hammer toward said striking position, and a cord connected to one of the keys of the piano keyboard and associated with said hammer, said cord arranged to be tensioned against a portion of said hammer by depression of said key to cause said hammer to rock to said striking position while leaving said hammer free to rebound from said string under the pressure of said spring.

4. In a striking and damping mechanism for pianos, adamper, a damper support adjacent the piano string-s having a groove therein, a spring mounting said damper on said support and resiliently supporting said damper in spaced relation to said support in a normal position of damping engagement with one of said strings, said spring being secured to said support by frictional engagement of the main body thereof with the walls of said groove and being yieldable to permit rocking of said damper away from said string.

5. In a striking and damping mechanism for pianos, a damper, a damper support adjacent the piano strings, means mounting said damper on said support .for rocking to and from a position of damping engagement with oneof said strings, saidmounting means including a spring yieldably resisting rocking of said damper away from said position, and means incapable of resisting longitudinally applied compressional 'forcesdirectly connected to one of the keys of the piano keyboard and to said damper, said means arranged to be tensioned by depression of said key to rock said damper away from said damping position.

6. In a striking and damping mechanism for pianos, a hammer having a base and striking tip, a hammer supporting rail adjacent the piano strings, a groove in said rail having a restricted throat, and a spring clip having a curved body portion fitted in said groove and frictionally engaging the Wall thereof, said clip having an end portion protruding through said throat and secured to said base of said hammer to yieldably support said hammer ina normal position with said tip spaced from said strings.

7. In a striking and damping mechanism for pianos, a damper having a base and. damping tip, a damper supporting rail adjacent the piano strings, a groove in said rail having a restricted throat, and a spring clip having a curved body portion fitted in said groove and frictionally engaging the walls thereof, said clip having an end portion protruding through said throat and secured to said .base of said damper to yieldably support said damper in a normal position with said 'tip in damping engagement with one of said strings.

8. A striking and damping mechanism for pianos which includes a hammer, a damper, means mounting said hammer and damper adjacent the piano strings for rocking to and from respective positions of striking and damping en gagement with one of said strings, said mounting means including a spring yieldably resisting rocking of said hammer toward striking position and a spring yieldably resisting rocking of said damper away from damping position, and a cord connected to one of the keys of the piano keyboard and to said damper and associated with said hammer, said cord arranged to be tensioned by depression of said key to rock said damper away from said damping position and then to rock said hammer into striking engagement with one of said strings while leaving said hammer free to rebound from said string under the pressure of said first named spring.

9. A striking and damping mechanism for pianos which includes a hammer, a damper, a supporting rail for said hammer and damper adjacent the piano strings, a first spring mounting said hammer on said rail and resiliently supporting said hammer in spaced relation to said rail in a normal position spaced from said strings, said spring being yieldable to permit rocking of said hammer into striking engagement with one of said strings, a second spring mounting said damper on said rail and resiliently supporting said damper in spaced relation to said rail in a normal position of damping engagement with said one of said strings, said second spring being yieldable to permit rocking of said damper away from said position, and means incapable of resisting longitudinally applied compressional forces operatively connecting one of the keys of the piano keyboard to said hammer and said damper and operative on depression of said key to rock said damper out of said damping position against the resistance of said second spring and then to rock said hammer again-st the resistance of said first spring into striking engagement with said one of said strings while leaving the hammer free to rebound away from said string under the pressure of said first spring.

10. A mechanism as claimed in claim 9 where- 8 in said means is directly attached to said key and said damper and extends about a curved surface of said hammer on the side of said first spring away from said strings.

11. A mechanism as claimed in claim 9 Wherein said rail is provided with a pair of grooves each having a restricted throat and said springs are each in the form of clips each having a curved body portion seated in one of said grooves and frictionally engaging the wall thereof, said clips each having an end portion protruding through said throat, said protruding end portion of one of said clips being attached to said hammer and said protruding end portion of the other said clip being attached to said damper.

HANS GUNN AR LINDEROTH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 316,062 Reissner Apr. 21, 1885 364,399 Dopp June 7, 1887 1,063,311 Abendschien June 3, 1913 1,167,863 West Jan. 11, 1916 1,176,655 Cross Mar. 21, 1916 1,563,526 Purrer Dec. 1, 1925 2,146,114 Finholm Feb. 7, 1939 2,227,741 Betz Jan. 7, 1941 FOREIGN PATENTS Number Country Date 736 Great Britain Feb. 19, 1880