US1335476A - Pneumatic action for pianos - Google Patents

Description

W. G. BETZ. PNEUMATIC ACTION FOR PIANOS.

APPLICATION FILED JUNE 1, I916.

Patented Mar. 30, 1920.

[EL/5277527. DMZ/25277515572.

2' 2755555." WQWKQLQQK UNITED STATES PATENT WILLIAM G. BETZ, OF BUFFALO, NEW YORK, ASSIGNOR TO STRA'UBE PIANO COMPANY, OF HAMMOND, INDIANA, A CORPORATION OF INDIANA.

PNEUMATIC ACTION FOR PIANOS.

Specification of Letters Patent.

Original application filed May 8, 1914, Serial No. 837,130. Divided and this application filed June 1, 1916.

- Serial No. 101,145.

lily invention relates to pneumatic actions for pianos, the present application which 18 i a division of my application filed May 8th, erial No. 837,130, Patent No. 1197596, be directed more particularly toaction operating mechanism. One of the principal objects 01': the present invention is to provide an improved construction for hanging or. supporting, and regulating, action levers whereby such levers and supporting arms are pr rably individually removable. In pneuznadc actions a bellows for each hamlner action is ordinarily provided and connecting links or levers are used for connectin the bellows and hammer actions. It is of advantage to be able to regulate the stroke of the bellows or connected levers and by my red construction I support the connecting link or lever by individually removable arms which also carry adjusting means for regulating thestroke of the bellows and connected levers. o

I will now refer to the accompanying drawing for a better understanding of my invention in which like reference characters indicate like parts and in which- Figure 1 is a sectional view illustrating he control mechanism of one key;

Fig. 2 is a face view of one valve mechanism with the cover of the air chamber removed;

- Fig. 3 is a side elevation of a valve lever;

Fig. 4: is a left side view of Fig. 3;

Fig. 5 is a detail view of a combined. valve lever support and valve seat; and

Fig. 6 is a sectional view through the center of Fig. 5; and

Fig. '7 is a plan view of a portion of Fi 1 showing the preferred method of independently mounting'the action levers and lever-supporting arms.

In the preferred embodiment of my invention as illustrated, I provide a so-called air chest or chamber A, comprising preferably vertically disposed facing walls 1 and having spacers as 3, 4, the cap or wall 2 Pianos, of which the following being attached by screws 5 so that it may be readily removed. This chamber A is, of course, of such length and width as to suitably take care of the desired number of valve mechanisms, as will be readily understood.-

A single valve mechanism B is shown comprising a plate 6 having a centrally disposed air port 7 formed so as to provide a valve seat 8, and above said port a pair of inwardly projecting ears 9 are formed, having concave formations 10 for supporting the valve lever shaft. Plate 6 is secured to the inner surface of the wall 1 preferably byscrews 11, the valve seat 8 projecting into a chamber 12 having a valve seat 13, said chamber 12 having an atmosphere duct 1% and bellows duct 15.

A valve lever 27 i is provided, having a pointed shaft 28, which is sprung between the resilient arms 9 and held between the concaved portion 10 in such a manner that the depending lever 27 is free to reciprocate without any lateral movement, thus doing away with guides, such as have been previously used. 7

At thecfree end of lever 27, a valve gate 29 is adjustably. attached by means of a screw 30, said valve vgate having facings preferably of leather, which act upon valve seats 8 and '18.

At a, point preferably intermediate of the pivoted end of lever 27 and the valve support 30, a buffer 31 i adjustably secured,

said buffer cooperating with a diaphragm 32, which is preferably of rubber or leather, and suitably fastened over the diaphragm actuating chamber 33. Chamber 33 is preferably round, and a duct 34: leads therefrom to a tube 35 extending to its tracker bar port 36. A connecting duct 37 leads from the main air chamber A to each duct 34:, there being a cap 38 provided with a small open ing inserted in each duct 37 to allow only a small flow of air. A tube from chamber A is also connected to the vacuum pump to create a vacuum in chamber .A in a wellknown manner.

It will, of course, be understood that in using my invention, the air chest is made wider than shown, and the associated bellows and valve mechanisms are staggered in accordance with well known practice.

ably fastened to the wall 1 in connection with duct 15 and is connected to a hammer action lever 16 by means of a connecting rod 17, which is pivotally attached at its upper end and held to the bellows extension 18 by a pair of ball faced nuts 19.

Each action lever 16 is pivotally secured to an individual arm 20, which is detachably secured to a rail or bar 21 preferably by means of screws 22, said rail being suitably supported, preferably by screws 23. An overhanging portion 20 of arm 20 carries an adjustable stop 24L, whereby the upward travel of action of lever 16 is determined. An adjustable buffer screw 26 is also carried by lever 16, which lever acts upon the action mechanism D, as will be readily understood.

Each action lever 16 and its supporting arm being individual units it will be apparent that they may be readily detached or replaced without disturbing others.

In the operation of the action, a vacuum is created in the air chamber A by suitable means, and with the music sheet covering the duct 36 a vacuum is also created induct 34. Thus the atmospheric pressure against valve 29 tends to hold valve lever 27' in its normal or inoperative position, and therefore the bellows C is maintained open. Upon opening tracker port 36, duct 34 tends to come up to atmospheric pressure, resulting in a pressure against diaphragm 32 by the pressure in chamber 33. Buffer 31 therefore acts upon lever 27, which causes valve gate 29 to leave its normal or air chamber port seat and engage the atmosphere duct seat 13, whereby the bellows chamber is connected to the chamber A by duct 15. A vacuum is thus created in the bellows chamber, allowing the atmospheric pressure to close the bellows, whereby the arm 18 is raised and through connecting rod 17 and lever 16 the hammer action mechanism D is actuated.

Upon closure of port again, duct and chamber 33 being connected to chamber A again have the pressure therein reduced so that the atmospheric pressure acting upon valve 29 through duct 1a, forces the valve gate 29 against its seat 3 and thus the bellows chamber being connected to atmosphere through ducts 15, 14, again opens and restores the action mechanism D.

Although in illustrating my invention 1 have chosen a preferred form, it is to be understood that it may be applied to other arrangements; neither do i desire to be limited to the construction shown as changes and modifications will readily occur to those skilled in the art, and I aim to cover all those changes and modifications as come struments comprising a horizontal rail,

action-operating bellows below the rail and extending transversely thereof, a horizontally-disposed action-lever positioned above each bellows lying longitudinally thereof and operatively connected thereto, independently-removable lever-supporting arms secured to said rail each pivotally supporting one of said action-levers, an extending portion individual to each of said arms overhanging the corresponding lever, and an adjustable stop carried by each of said ex-- tending portions for controlling the travel of the corresponding arm.

3. A pneumatic action for musical instruments comprising a horizontal rail, leversupporting arms independently and detachably secured at one end to the rail and projecting laterally therefrom, an actionlever for each arm having one end pivotally attached to an intermediate portion of the arm whereby an extending portion of the arm is positioned adjacent an intermediate portion of the lever, and adjusting means for regulating each lever carried by the extending portion of the associated arm.

A pneumatic action for musical instruments comprising a supporting rail, straight rectangular elongated lever supporting arms independently and detachably secured at one end to a horizontal side of the rail and projecting laterally therefrom, an actionlever for each arm having one end pivotally attached to an intermediate portion of the arm whereby the free extending portion of the arm is positioned adjacent an intermediate portion of the lever, and adjusting means for regulating each lever carried by the extending portion of the associated arm.

Signed by me at Chicago, county of Cook and State of Illinois, in the presence of two witnesses.

WILLIAM G. BETZ. Witnesses:

GEORGE E. MUELLER, JENNIE B. STALEY.

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