US414488A

US414488A - Best available cops

Info

Publication number: US414488A
Authority: US
Publication date: 1889-11-05
Anticipated expiration: 1906-11-05

Description

G. BRAMBAGH.

Patented Nov. 5, 1889.

A TTORNEY KEY BOTTOM FOR PIANOS.

(No Model.)

.4 z 2 4 w i a w WITNESSES:

UNITED STATES PATENT OFFICE.

CARL BRAMBACH, OF NElV YORK, N. Y.

KEY-BOTTOM FOR PIANOS.

SPECIFICATION forming part of Letters Patent No. 414,488, dated November 5, 1889.

Application filed May 11, 1889.

Serial No. 310,409. (No model.)

.To all whom it may concern.-

Be it known that I, CARL BRAMBACH, of thecity, county, and State of New York, a citizen of the United States, have invented certain new and useful Improvements in Key-Bottoms for Pianos, of which the follow ing is a specification.

This invention relates to an improved keybottom regulator by which the key-bottom can be readily set when the same is getting out of regulation by a change of atmosphere or any other cause, the regulating being ac complished with great facility and at a considerable saving of time and labor. My improved regulator is designed for the purpose of overcoming the warping of the key-bottom and for readjusting the keys either to- -ward or away from the action, as may be required.

The invention consists of a key-bottom regulator consisting of a key-bottom having transverse slits at the center and at intermediate points, and of two longitudinal bracket-bars that are attached to the bottom of the keeper and connected at their inner surrounding parts by a right-and-lefthand screw, so as to be adjusted relativelyto each other as required by theproper adj ustment of the keys.

In the accompanying drawings, Figure 1 represents a front elevation of a key-bottom with my improved regulating device. Fig. 1 is an enlarged detail View of the adjusting-screw. Fig. 2 is a vertical transverse section of the same on the line :20 :13, Fig. 1; and Fig. 3 is a modified construction of an adjusting-screw for the bracket-bars of the key-bottom.

Similar letters of reference indicate corresponding parts.

In the drawings, A represents the key-bottom, which is provided at the center and at one or more intermediate points between the center and ends with transverse slits or notches a, which extend from the upper edge in downward direction, the center of the slit abeing of greater depth than the intermediate slits, as-shown in Fig. 1. The key-bot tom is supported on two independent longitudinal bracket-bars B, which are screwed to the, under side of the key-bottom and located below the recess at the rear ends of the key levers. The inner ends of the bracket-bars B B are each provided with a downwardly-extending flange l), which are con nected by a right-and-left-hand screw 0, having a square head for the tuning hammer.

. In place of the right-and-left-hand screw, any

other adj Listing-screw may be used, as shown in Fig. 3, in which case one end of the screw must be mounted in the flange b of one of the bracket-bars, while the threaded shank of the screw engages the flange of the other bracket-bar.

\Vhen the key-bottom has warped upward or downward for some reason or other, so that the key-levers change their relative positions to the action, the proper position of the key-bottom is restored by turning the right-and-left-hand connecting-screw G with the tuning hammer, whereby the key-bottom is lifted and the keys adjusted. The eifect of the adjustment of the screw 0 is greatest at the center and smallest at the ends of the key-bottom, which corresponds to the usual warping of the key bottom.

The slits in the key-bottom may be dispcnscd with; but in this case the regulatingbars have to be of greater thickness, so as to produce the adjustment of the key-bottom; but I prefer the use of slits, as the regulating of the key-bottom is thereby facilitated. The key-board regulator has therefore twofold purposes-first, supporting the key-bottom and keys in proper position, and, secondly, for adjusting the warp in the bottom, which is accomplished by considerable saving in time and labor by a simple application of the tuning-hammer without requiring a of the key-bottom, substantially as set forth. 10o

- 2. lhe combination, withakey-bottom hav- In testimony that I claim the foregoing as ing one or more transverse slits or notches, my invention Ihave signed my name in presof longitudinal bracket-bars attached to the ence of two subscribing witnesses.

under side of the key-bottom, and a right-and- CARL BRAMBACH. 5 left-hand screw connecting the inner ends of Witnesses:v

the bracket-bars for regulating the key-bot- MARTIN PETRY,

tom, substantially as set forth. A. R. ANGUS.