US2411005A

US2411005A - Escapement action for grand pianos

Info

Publication number: US2411005A
Application number: US587091A
Authority: US
Inventors: Schulze Reinhard
Original assignee: Individual
Current assignee: Individual
Priority date: 1945-04-07
Filing date: 1945-04-07
Publication date: 1946-11-12
Anticipated expiration: 1963-11-12

Description

Nov. 12, 1946. R. SCHULZE ESCAPEMENT ACTION FOR GRAND PIANOS Filed April '7, 1945 \wuq... 1

Patented Nov. 12, 1946 UNITED STATES PATENT OFFICE 2,411,005 ESCAPEMENT ACTION FOR GRAND PIANOS Reinhard Schulze, Baltimore, Md. Application April 7, 1945, Serial No. 587,091

(or. s4 2s9) 4 Claims. 1

This invention relates to an improvement in the escapement action of a grand piano and relates specifically to means to lighten the touch required on the piano keys.

The hammer and stem of the escapement action of the grand piano can be reduced in weight to a certain extent, but beyond that extent it cannot be reduced further to give the proper tone on the piano strings. The hammer stem, carrying the hammer, is pivoted at its fixed end and the knuckle on that stem is removed from that pivot about A; of the length of the stem. The weight of the hammer that must be therefore moved by the keys is about 8 times the actual hammer weight because of this levera e.

Before repetition levers were used, it was proposed to place a spring on the hammer stem to lessen the weight of the hammer so that it would not fall so rapidly and so that a note could be repeated without having the hammer fall all the way down to its rest. Similarly even'since repetition levers have been used, it has been proposed to place a spring on a hammer to lighten the hammer weight and consequently lighten the piano key touch. Springs heretofore designed have lacked utility partly because of their rigidity and partly because of their unadjustability. This unadjustability of the spring tension on the installed piano made it substantially impossible to properly adjust the piano action if once it got out of adjustment;

The spring of the present invention not only allows for the complete adjustability of the tension of that spring, including the actual measurement of that tension, but it allows also for its complete inaction when the other parts of the piano action are to be adjusted. It is so made and positioned as to substantially disappear when other adjustments are required on the piano action.

Other objects and advantages of the invention will be apparent from the following description and the accompanyin drawin formin a part hereof and in which:

Figure 1 is a fragmentary side elevation of a grand piano escapement action.

Figure 2 is a fragmentary plan View of the hammer stem and its mounting.

Figure 3 is a sectional view on line 33 of Figure 1.

Figure 4 is a perspective view of the hammer knuckle showing the cord loop attached thereto.

Figure 5 is a fragmentary side elevation showing the hammer stem folded back.

In the drawing similar numerals refer to simwith its regulating button H resting against the pad H on the pivoted end of wippen 5. The upward movement of the lower end of the repetition lever is limited by check l2 and the lever is held in the position shown by spring 1 3 passing through loop l4 fast in the wippen 5. Tension of the spring i3 is adjusted by screw 15. Rail 16 has hammer flange l'l fast thereto. To this flange hammer stem lBis pivoted at It and the stem is has hammer l9 at its free end. Rest rail 20 is padded at 20' as shown and the other parts are padded likewise as shown and as is usual in the construction of these actions.

The hammer stem has a padded knuckle 2i thereon against which the head of the jack 3 strikes in sounding a note. A fillet 22 holds the knuckle 2! on the stem l8 and the distance between the pivot point of the stem and the fillet is about /8 of the total length of the stem. A loop cord 23 has its free ends glued fast in-the fillet as shown, in Figures 3' and 4. The cord passes through opening 24 in the stem. The stem also has opening 25 therein on the other side of the knuckle, toward the hammer. A coil spring 26 is pivoted on padded pivot 27 and is counter-sunk in opening 28 in flange l1. One free end of this coil spring 26 is held by screw -29 which may be moved up or down to adjust the tension exerted by the spring. The other end, 33, of the spring 25 has thereon a hook 3i passing through the loop of cord 23. The tension of the spring as imparted to the stem I8 is directly over the center of the knuckle and in proportion to the tension on the spring lessens the weight of the hammer upon its initial rising. It is important that the tension on the spring be substantially negligible at the time the hammer strikes the string, so that the hammer will obtain sufficient momentum in its fall to push down the repetition lever against the action of its spring [3, so that the backcheck 3 will be able to function against the lower end of the hammer [9 to check the hammer to make possible the rapid repetition of a note. The opening 24 is shaped to allow the free movement of the cord 23 therein without contact at any time.

When it is desired to raise the stem l8 on its pivot, as shown in Figure 5, the end 30 of the spring with its hook 3| slides into opening 25 in the stem and the hook 3| slides off the loop of cord 23 as shown in Figure 5. This construction allows for raising the stem as shown in Figure without increasing the tension on the spring 26 or otherwise injuring it in any manner. The hook 3| resumes its proper position in the loop 23 simply by lowering the hammer stem 18 to its proper position as shown in Figure 1. It is often important to raise the hammer stem to adjust the tension on spring l3 or to change the position of the button I l or to take out the whole wippen 5 and its attached parts. The construction of the spring and its attachment to the ham-. mer flange and stem makes possible the substantial disappearance or elimination of the spring when the stern must be raised for these purposes. a

It will be apparent that a lighter hammer on the initial blow, as is provided by the use of this spring, will make possible a lesser tension on the repetition lever spring 13; A lighter hammer will also obviate the necessity of so much weight at the fingerin end of the keys I. The amount of tension on the spring 26 is substantially trebled in the lighter touch required on the key because of the lesser tension allowed on the repetition lever spring i3 and the lighter weight in the keys I.

By this invention a most sensitive touch only is required upon the key to produce a note of the same firmness and resonance as heretofore produced by a much heavier touch and the repetition of a note becomes far more easy and sensitive because of the spring.

What is" claimed as new and is desired to be secured by Letters Patent is:

1. A grand piano action comprising a hammer rail having a hammer flange fixed thereon, a hammer stem with a hammer thereon, the stem being pivoted to said flange, a knuckle on the underside of said stem. near the pivoted end thereof, a pivot extending transversely of said flange, a piece of resilient wire having its intermediate portion coiled about said pivot, said wire havin one end secured to said flange and the other end secured to said stem adjacent the knuckle, to exert a lifting action on the hammer stem.

2. A grand piano action comprisin a hammer rail having a hammer flange fixed thereon, a hammer stem with a hammer thereon, the stem being pivoted to said flange, a knuckle on the underside of said stem near the pivoted end thereof, a pivot extending transversely of said flange, a piece of resilient wire having its intermediate portion coiled about said pivot, said wire having one end secured to said flange and the other end secured to said stem adjacent the knuckle, to exert a lifting action on the hammer stem, said stem having a vertical opening therethrough adjacent the knuckle and toward the hammer, the end of the wire secured to the stem passing freely into the opening upon the elevation of the stem.

3. A grand piano action comprising a hammer rail having a hammer flange fixed thereon, a hammer stem with a hammer thereon, the stem being pivoted to said flange, a knuckle on the underside of said stem'nea'r the pivoted end thereof, a coil spring transversely and horizontally pivoted in said flange, said stem having a vertical opening therethrough adjacent said knuckle toward the pivoted end of the stem, a cord loop extending through said opening fixed adjacent said knuckle, said spring having one end passingover the stem and through said loop, and the other end being adjustably held on the said flange, whereby the spring tension may be varied, to impart a lifting action to the hammer stem.

4. A grand piano action comprising a hammer rail having a hammer flange thereon, a hammer, a stem supporting the hammer and being pivoted to the flange, a knuckle on the underside of the stem near the pivoted end thereof, said stem having two vertical openings there through adjacent the knuckle, one toward the pivoted end, the other toward the hammer, a

piece of resilient wire having an intermediateportion wound into a coil pivoted transversely of said flange, one end of said wire being secured to the flange and the other end being securedto a loop passing through the stem opening toward the stem pivoted end, and passing into the other opening upon the elevation of the stem.

REINHARD SCHULZE.