US2138517A

US2138517A - Piano-action spring

Info

Publication number: US2138517A
Application number: US131544A
Authority: US
Inventors: Sieveking Martinus
Original assignee: Individual
Current assignee: Individual
Priority date: 1937-03-18
Filing date: 1937-03-18
Publication date: 1938-11-29
Anticipated expiration: 1955-11-29

Description

Nov. 29, 1938. I M. SIEVEKING v 2,138,517

PIANO ACTION SPRING l Filed March 18, 1937 MAR T/NUJ 5/15 VEK/NG I N V EN TOR.

ATTORNEY V Patented Nov. 29, 1938 UNITED STATES PIANO-ACTION SPRING Martinus Sieveking, New York, N. Y.

Application March 18,

2 Claims.

This invention relates to an improved action for grand pianos and more particularly to an improved compound repeating lever and jack spring. This invention is an improvement on my piano-action spring shown and described in Letters Patent of the United States, No. 2,046,853, issued to me on July 7, 1936.

In grand piano actions of the type herein shown, it is necessary to periodically regulate the tension exerted by the repeating lever actuating spring. It has been found desirable to make the repeating lever actuating spring as long as possible so as to obtain the maximum resiliency in the spring and so that a heavy gauge spring wire may be employed. The longer the repeating lever actuating spring is made, the more readily will it absorb the rebound of the hammer blow and therefore cause smoother repetition of the action.

An object of this invention is to provide a compound piano action spring having free and slidable end portions for actuating the repeating lever and the jack, and a looped end portion, the said spring being made of a single length of wire and the repeating lever actuating portion being of extensive length and secured at two points in the support.

Another object of this invention is to provide a compound piano action spring formed to provide three integrally connected sections, each section having an independent function.

With the above and other objects in view, the invention will be hereinafter more particularly described, and the combination and arrangement of parts will be shown in the accompanying drawing and pointed out in the claims which form part of this specification.

Reference will now be had to the drawing, wherein like numerals of reference designate corresponding parts throughout the several views, in which:

Figure l is an elevation of a grand piano action embodying my invention, the repeating lever being partly broken away.

Figure 2 is a view of the spring in inoperative position.

Figure 3 is an end view of the spring showing a plurality of coils in the looped end portion thereof.

In the illustrated embodiment of the invention, the numeral ill indicates a grand piano action comprising a support Ii and a top flange l2 having a pivot i3 upon which has been mounted a repeating lever I4. A jack l5 has been pivotally 1937, Serial No. 131,544

mounted on a pivot 25 at one end of the support II.

A compound spring I 6 having an upper portion IT, a lower portion i 8, a loop 19 and an extension 2% has been secured by a clamp 22 to the support I I. The upper portion I! has a free end 28 in flexed and slidable engagement with the lower surface of the repeating lever M. The lower portion I8 is bent at 29 and passes freely through an aperture 26in the flange l2. The aperture 26 is of larger diameter than the diameter of the spring wire. The lower end of the portion i8 is in flexed engagement and in free and slidable relation with the jack 15. The extension 20 adjoins a curved portion 2| and is in angular relation therewith.

It is to be noted that the compound spring i5 is formed to provide three integrally connected sections, each section having a definite function to perform in the piano action.

It will thus be noted that my compound spring performs all the functions necessary for an efficient grand piano action, in that it makes pos sible a long repeating lever actuating section, that the upper and lower end portions can flex independently of each other, and resulting in a piano action spring having a much longer life than those heretofore in use.

It is to be noted that the spring is secured directly by a wire clamp 22, without any felt bushing. As best shown in Figure 1, the spring l6 has bearing in the support H on the straight line portion 20 and on the curved line 2| and that the spring bears at least at two points spaced apart on the support.

The structure shown in Figure 1 permits the spring 16 to be inserted and removed from an assembled vn'ppen and secured in place by only one member, the clamp 22, by adjusting the nut at the lower end of the clamp. This structure is much more simple than that shown in my prior patent wherein it was necessary to manipulate three screws in the handling of the spring.

I claim:

1. In a grand piano action comprising a sup port having a fixed flange and a pivotally mounted jack and a repeating lever, said flange having a through aperture at its lower end and said support having a curved seat; a spring made of a single length of wire and having a looped end and upper and lower sections having free ends, said upper section having its free end in flexed and slidable engagement with the repeating lever, a lower section passing freely and in non-contacting relation through said flange aperture and having its free end in flexed and slidable engagement With the jack. said looped end being substantially unsupported and freely flexible, said looped end having a linear extension and a curved portion resting in said curved seat, said curved portion terminating in a substantially upright direction and joining said lower section, said extension being adapted to be clamped to said support at said curved portion at one point, whereby said spring is freely slidable at both ends and fixed at only one intermediate point.

2. In a grand piano action of the character described, a spring made of a single length of wire and having a looped end and upper and lower sections having free ends, said upper section MARTINUS SIEVEKING.