US1092163A - Piano-player action. - Google Patents

Description

APPLICATION FILED .APR. 28, 1911.

J. A. OBST.

PIANO PLAYER ACTION.

Patented Apr. 7, 19m

2 SHEETS-SHEET 1.

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-PIANO PLAYER ACTION.

APPLICATION FILED 'APR. 28, 1911. 1,092,1 63. Pa ented Apr. 7, 1914 2 SHEETS-SHEET 2.

I I n enz or 5 i t orn wfl m JOSEPH A. OBST, 0F PAWTUCKE'I, RHODE ISLAND.

PIANO-PLAYER ACTION.

Specification of Letters Patent.

Patented Apr. 7, 1914.

Application filed April 28, 1911. Serial No. 623,805.

To all whom it may concern:

Be it known that I, JOSEPH A. OBSI, a citizen of the United States, residing at Pawtucket, in the county of Providence and State of Rhode Island, have invented a new and useful Improvement in Piano- Player Actions, of which the following is a specification accompanied by drawings, forming a part of the same.

The object of my invention is to provide a simple, inexpensive and efficient mechanism for operating the tone producing action of a piano, and I accomplish this object'by the construction andarrangement of parts as hereinafter described and pointed out in the annexed claims.

Referring to the accompanying drawings, Figure 1 represents a front view of so much of a piano playing mechanism as is necessary to illustrate my present invention. Fig. 2 's a side View of one of the operating units, shown in section on the plane of the broken line 22, Fig. 1. Fig. 3 is a side view of a portion of one of the operating units, shown in sectional view on the plane of the broken line 8-3, Fig. 1, and the broken line 3, Fig. 6. Fig. 1 is a front view of the lower end of one of the lifting wires for actuating the piano action. Fig. 5 is a longitudinal sectional view of one of the.

units 4, showing a modification in construction. Fig. 6 is a plan view, shown in section, representing two of the modified form of gunits with the connected air passages. 'The right hand side of Fig. 6 shows the section on the plane of the broken line 6-6, Fig. 5, and the left hand side of Fig. 6 shows the section on the plane (B -6, Fig. 5.

Similar reference characters refer to similar parts in the different figures.

The mechanism embodying my present invention is intended to be actuated inithe usual manner by means of an air exhausting mechanism, and controlled by the passage of a perforated sheet of paper over the apertures of a tracker board in the usual mannor in piano playing mechanisms of this class. I have not deemed it necessary to show the tracker boardor the air exhausting mechanism, as their connection with a pneumatic piano playing mechanism willbe well understood. Each of the tone producing mechanisms of a piano action are operated "fixed framework 15, of the broken line' upon by an individual motor mechanism, constituting a unit of the player action.

Referring to the accompanying drawings, 1, 1 represent two cases placed on opposite sides of the player action and inclosing chambers 2, 2, from which the air is'exhausted by any of the means in common use, ordinarily by a bellows operated by foot pedals. The chambers 2, 2 are connected by air passages or wind trunks 8 inclosed in cases 3 To the cases 3 I attach the units 'of the player action, some of which are shown at 4, Fig. 1, one being shown in longitudinal sectional view in Fig. 2. Each of the units 4 consists of a box or case which incloses a vacuum chamber 5, which. communicates by an air passage 6 with one of the wind trunks 3 so that, as the air is exhausted from the chambers 2, 2 and wind.

trunks 3, a partial vacuum or reduced air tenslon is maintained in the vacuum chambers 5.

As the units 1 are duplicates, a description of one, as illustrated in sectional view in Fig. 2, will be sufficient. Inclosed within the unit 4 is a motor bellows 7 having its stationary leaf 8 attached to the bottom of the vacuum chamber. The movable leaf 9 of the motor bellows 7 is connected by a short lever 10 with a vertically slidable wire 11, which passes through an opening in the top of the unit and is provided at its upper end with an adjustable head 12, adapted to strike against an arm 13 as vmotor bellows is raised. The arm 13 is atthe movable leaf of the tached to 'a lifting wire 14 which slides in a 15 and carries at its upper end anadjustable head 16, adapted to strike against the wlppen or other suitable part of the piano action.

The motor bellows 7 communicates by an air passage 17 with an air chamber 18 inclosed within the vacuum chamber 5. The air chamber 18 communicates through a port 19 with the outside air and through a port 20 with the vacuum chamber 5. The ports 19 and 20 are arranged to be alternately opened and closed by means of valves 21 and 22 carried upon a valve stem 23, the lower end of which normally rests by gravity upon a diaphragm 2 1 which covers an'air chamber 25. The chamber 25 communicates by an air passage 26 with one of the apertures of the tracker board through the means of a connecting rubber tube, not shown. In the normal position of the valve stem 23, as shown in Fig. 3, the port 19 is closed while the port 20 is opened, producing a partial vacuum in the air chamber 18; while in Fig. 2, the valve stem is represented in its raised position, causing the port 19 to be opened and the port 20 to be closed.

The downward movement of the valve stem 23 is caused by gravity whenever the pressure is removed from beneath the diaphragm 24, which occurs when the opening in the tracker board communicating with the chamber 25 is closed by the music sheet, when the air is exhausted from the chamber 25 through a bleed opening 27, connecting the passage 26 with the vacuum chamber 5. As the upper side of the diaphragm 24 is exposed to the vacuum chamber, the passage of air through the passage 26 will create a pressure against the under side of the diapghragm sufficient to raise the valve stem 23.

y the control of the music sheet, therefore, a vertical movement is imparted to the valve stem 23-, causing the air chamber 18 to be alternately connected with the outside air through the port 19' and with the vacuum chamber through the port 20; Whenever air passes through the port 19 and air passage 17, the motor bellows 7 becomes inflated, raising the movable leaf 9 within the vacuum chamber 5 and lifting the slidable wire 11, arm 13 and lifting wire 14 to actuate a corresponding part of the piano action.v

When air is shut off from the chamber 25 by the passage of the music sheet over an opening in the tracker board, the air already in the chamber 25 is exhausted through the bleed opening 27 into the vacuum chamber, equalizing the air pressure upon opposite sides of the diaphragm 24 and allowing the valve stem 23 and the valves carried thereby to fall by gravi'tv from the position shown in Fig. 2 to that shown in Fig. 3, causing the valve 21 to close the port 19 and the valve 22 to open the port 20. In this position of the valves 21 and 22, as shown in Fig. 3, the

chamber 25 and air passage 17 are closed to the outer air and connected through the port 20 with the vacuum chamber 5, thereby exhausting the air from the motor bellows 7. This allows the movable leaf 9 and connected vertically movable wire 11 to fall, thereby relieving the arm 13 and the lifting wire 14, which fall by gravity. Attached to the movable leaf 9 of the motor bellows is an elastic arm 28 fastened to the movable leaf near its center by screws 29. Attached to the free end of the arm 28 is a valve 30, which is lifted from a supplemental opening 31 leading from the vacuum chamber 5 to the air passage 17 by the downward movement of the movable leaf 9. The supplemental opening 31 is normally open between the air passage 17 and the vacuum chamber 5 and is only closed by the valve 30 as the movable leaf 9 approaches its highest position, which causes the elastic arm 28 to be slightly lifted from the movable leaf 9, as shown in Fig. 2.

In the operation of the mechanism the bleed opening 31 is open until the movable leaf 9 of the motor bellows has been partially expanded, when the valve 30 closes the bleed opening 31. The elasticity of the spring 28 permits the expanding movement of the leaf 9 to be completed. lVhen air has been cut off from the interior of the motor bellows the movable leaf 9 collapses, the bleed opening 31 being kept closed until the tension on the spring 28 has been removed, when the continued collapsing movement of the leaf 9 opens the bleed opening 31 and facilitates the rapid movement of the leaf 9. This quickens the action of the motor bellows and is of especial advantage in sounding repeated notes.

The lifting wire 14 is provided with a cylindrical block or base 32, which slides through the framework 15 and is provided with a slot 33 which receives a pin 34 held in the frame 15 in order to hold the wire 14: from rotation. The arm 13 is adjustably held on the lifting wire 14 by means of a set screw 35, which enables the position of the lifting wire 14 to be adjusted vertically relatively to the position of the wire 11 and the movable leaf 9 of the motor bellows. Attached to the cover or top of the unit 4: is a block 36 containing a portion of the air passage 6, and the blocks 36 are attached by screws 37 tothe cases 3 of the wind trunks 3, thereby enabling each of the units to be readily detached from the wind trunks and removed lengthwise from the apparatus.

The bleed opening 27 is formed by boring a hole through the end wall of the vacuum chamber 5 and closing the outer end of the hole by a valve 38 held on the free end of an elastic arm 39, attached to the end wall of the unit by a screw 40. The units 4 consist of a rectangular box having the end walls and top and bottom of material sufliciently thick to receive the screws 41 by which the side plates 42 are attached.

In Figs. 5 and 6 I have shown a modification of the apparatus, in which the port 19, instead of opening to the outside air as in Fig. 2, opens into a chamber 43 inclosed in a casing 44, said casing 44 and block 36, as shown in Fig. 2, being integral and attached to a unit 4. The attaching screws 37, by which the units are attached to the wind trunks in the modified form of construction, pass through the casing ll upon each side of the chamber 43. The wind trunks in the modified form shown in Fig. 5 comprise a casing 45, having chambers 16 and 47 extending throughout the entire while a plenum is maintained in the length of the wind trunks and communicating at opposite ends with chambers 48 and 49 in the casing 50, Fig. 6. The chamber 46 communicates by the passage 6 with the vacuum chamber 5 inclosed in the unit 4, and the chamber 47 communicates by an air passage 51 with the air chamber 43. The chambers 46 and 48 are connected with suitable mechanism for exhausting the air therefrom, as already described with reference to the wind trunk 3, Fig. 2, while the chambers 47 and 49 are connected with a suitable mechanism for supplying air thereto, by which the normal atmospheric pressure is increased. By this means the air tension in the chamber 46 is reduced and that in the chamber 47 is increased and, by means of the connecting passages 6 and 51, a partial vacuum is maintained in the vacuum chamber 5 of each individual unit 4,

chambers 43 of each individual unit. Under this condition of air tensions, the valve stem 23 and connected valves are raised by the atmospheric pressure in the pneumatic chamber 25, due to the difference in area between the valve 21 and that of the pneumatic diaphragm 24.

By the construction shown in Fig. 5, an increased force may be imparted to the movable leaf 9 of the motor bellows 7 above that due to the normal atmospheric pressure, thereby enablinga smaller motor bellows to be used to produce an equal force upon the lifting wire 14.

I have not deemed it necessary to represent the tracker board, music sheet, or the mechanism for exhausting air from the vacuum chambers 5 of each of the units 4, or the mechanism for increasing the air pressure in the chambers 43, as the apparatus producing these results are in common use and their construction and operation will be well understood by those conversant with this class of mechanisms.

By the construction shown in the accompanying drawings and herein described, I simplify the construction of a player mechanism and inclose all the operative parts within dust proof casings, and the individual units 4 may be separately removed from the apparatus by withdrawing the two attaching screws 37. I am also able to obtain a greater range and flexibility of construction from soft to loud and Vice versa, 7

I claim,

1. In a mechanism of the class described, a vacuum chamber, a motor bellows, a valve controlled air passage between said motor bellows and said vacuum chamber, a pneumatically operated valve for controlling said air passage, a second air passage between said motor bellows and said vacuum chamber, and a valve operated by the action of said motor bellows for controlling said second air passage.

2. In a mechanism of the class described, a motor bellows, means for supplying air to said motor bellows, a vacuum chamber, an air passage between the motor bellows and the air chamber, a supplemental bleed passage between said vacuum chamber and said motor bellows, an elastic arm carried by the movable leaf of said motor bellows, and a valve carried by said elastic arm for closing said supplemental bleed passage.

8. In a mechanism of the class described, a motor bellows, means for supplying air to said motor bellows, a vacuum chamber, an air passage between the motor bellows and the vacuum chamber, a supplemental bleed passage between said vacuum chamber and said motor bellows, and means controlled by the movement of the movable leaf of said motor bellows for closing said supplemental bleed passage.

4. In a mechanism of the kind described, a series of wind trunks, means for exhausting air from the ends of said wind trunks, casings suspended beneath said wind trunks each inclosing a vacuum chamber communicating with a wind trunk, a motor bellows inclosed in said vacuum chamber, an air chamber inclosed in said vacuum chamber provided with an opening through which air is exhausted from said air chamber directly into said vacuum chamber, a valve for closing said opening, and a pneumatic diaphragm exposed in said vacuum chamber for actuating said valve.

Dated this 25th day of April, 1911.

JOSEPH A. OBST. WVitnesses:

WILLIAM MEGKLEJOI-IN, GEORGE WV. MILLER.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. G.

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