US3255657A - Piano frame and bridge bar therefor - Google Patents

Description

June 14, 1966 c. w. ANDERSEN 3,25

PIANO FRAME AND BRIDGE BAR THEREFOR Filed July 1. 1963 INVENTOR.

United States Patent Ohio Filed July 1, 1963, Ser. No. 291,929 2 Claims. (Cl. 84209) This invention relates generally to struck-string pianos and analogous musical instruments and relates more particularly to an arrangement for mounting the strings of such instruments.

According to conventional practice, the strings of a piano are stretched across a frame; and spaced bars or bridges are raised from the frame to engage the strings and determine the vibrating length thereof. A considerable problem resides in preserving the lateral position of the strings. For example, a displaced string can easily come into vibrational contact with an adjacent string whereby to develop spurious sounds; and in addition, a string may become so extremely displaced laterally as to be out of alignment with the percussive path of its striking hammer. Complete failure to sound such a string results. In the past, it has been proposed to solve the p-noblem of string displacement by notching the upper bridge bar; but this notching of the upper bridge bar has been found to make the string sing or generate undesirable sounds.

Therefore, an important object of the present invention is to provide means for laterally locating a piano string in full preservation of its desired vibrational characteristics.

A more general object of the invention is to provide a new and improved piano frame arrangement and bridge bar therefor.

These and other objects and features of the invention will become more apparent from a consideration of the following description.

A piano frame arrangement in accord with the invention includes spaced bridge bars adapted to define therebetween the vibrating span of a piano string. In compliance with the invention, a format-ion defining a notch is disposed adjacent one of the bridge bars outside of the space between the bridge bars for controlling the position of a piano string situated interjacent the walls of the notch.

In order that the principle of the invention may be read- Patented June 14, 1966 ICC Depression of the forward end of piano key lever 22 is arranged to cause a striking of the corresponding piano string through one of the individual actionrnechanisms incorporated in the action assembly :16. The individual action mechanism associated with the key lever 22 is indicated generally by the numeral 32. A main rail 34, a hammer rail .36 and a regulating rail 38 extend through the body of the piano structure 10 to support and cooperate with each of the action mechanisms 32, action brackets 40 and tubular action spacers 142 being used to mount the rails 34, 36 and 38 in place.

The action mechanism 32 includes a hammer 44 that is mounted to a butt knuckle 46 by a hammer shank 48, the butt knuckle 46 being pivotally mounted to the main rail 34 by a butt flange '50. Depression of the piano key lever .22 is arranged to actuate hammer 44 by means of a sticker or abstract 52 that is detachably aflixed at one end of the key lever 22 by means of a coupling arrangement 54. The sticker 52 is swingably mounted at its other end to a whip 56, and the whip 56 is pivotally mounted to the main rail 34 by a whip flange 58. A fly or jack 60 is pivotally mounted to the whip 56 by a fly flange 62. The head of fly 60 engages a cushioned surface on the butt knuckle 46, and a felt covered regulating rail button 64 is mounted to regulating rail 38 for cooperative engagement with a heel portion 66 of the fly 60. Depression of the piano key lever 22 causes the sticker 52 to rise with a resultant pivoting of the whip 56. Engagement of the heel portion 66 of the fly with the regulating rail button 64 impels the hammer 44 into percussive engagement with a correspondingpiano string 68 that is mounted on the piano frame 14.

A partially felt-surfaced backcheck 70 is fastened to the Whip 56 in upstanding relationship by means of a backcheck wire or rod 72; and a cooperatively felt-surfaced catcher 74 is secured to the butt knuckle 46 by means of a catcher stem or shank 76 which radiates from the butt knuckle. The action mechanism. 32 also includes a metal spoon 78 which is affixed to the whip 56 in upstanding relationship, being disposed on the end of the whip which is opposite the connection with abstract 52. Upon actuation of the whip 56 by means of the key ily understood, a single embodiment thereof applied to an upright piano, but to which the application .is not to be restricted, is shown in the accompanying drawing wherein:

FIG. 1 is a central sectional view taken through an upright piano to show the operating elements thereof, including a piano frame arrangement constructed in compliance with the invention;

FIG. 2 is a perspective View on an enlarged scale of the piano frame arrangement of FIG. 1; and

FIG. 3 is an enlarged perspective view of the piano frame arrangement of FIG. 2, showing in particular the notch formed in the auxiliary bridge bar.

Referring now in detail to the drawing, specifically to FIG. 1, an upright p'iano structure indicated generally by the numeral 10 will be seen to include a keyboard 12, a piano string frame 14 and an action assembly 16. The keyboard 12 includes a keybed 18, a keyframe 20 and a number of key levers such as key lever 22. The keyframe 20 is mounted on the keybed 18 and includes a balance rail 24 into which upstanding balance rail pins 26 are inserted. Each key lever 22 is slotted to receive a balance rail pin 26 for fulcruming the key lever; and the keyframe 20 also includes a back rail 28 to which a of the key lever 22.

lever 22, the spoon 78 contacts the lower, felt-surfaced end of a damper lever 80, damper lever. 80 being swingably mounted to the main rail 34 by means of a damper lever flange 82. The spoon 78 is specifically arranged to operate damper lever 80 so as to retract a damper head 84 from contact with the piano string 68 immediately in advance of the hammer 44 striking the string.

The piano string frame 14 is ordinarily fabricated from steel and includes an upper frame section 86 and a lower frame section 88 which is spaced from the upper frame section. In order to provide mounting sites for the piano string 68, a hitch pin 90 is mounted in the lower frame section 88 and a bore 92 is fashioned in the upper frame section 86 spaced from the hitch pin to receive a tuning pin 94. The piano string 68 includes a loop end 96 which is fitted over the hitch pin 90, the opposite end of the piano string 68 being attached to the tuning pin 94 in a wrapped manner. The upper frame section 86 is provided with an upper frame bridge bar or abutment forma tion 98, and the lower frame section 88 is provided with a lower frame bridge bar or abutment formation 100,

bridge bars 98 and 100 being appropriately spaced apart board bridge 106 is mounted to the soundboard 104 in physical contact with the piano string 68 to couple the vibration of the string to the soundboard. Bridge pins 108 are mounted on the soundboard bridge 106 on opposite lateral sides of the piano string 68 to preserve the lateral positioning of the lower end of the string.

Turning to a consideration of FIG. 2, the bridge bars 98 and 100 are seen to define elongated members of triangular section, each of the elongated bridge bars 98 and 100 including an apical ridge 110 for contacting transversely and supporting a plurality of the piano strings 68. In compliance with an important feature of the invention, an auxiliary bridge bar or abutment formation 112 is raised from the upper frame section 86 closely adjacent the bridge bar 98. The auxiliary bridge bar 112 is fashioned to be an elongated member of substantially triangular section, and the auxiliary bridge bar 112 is specifically arranged to include an apical ridge 114 which is fashioned with a series of spaced notches 116 out therein. Each notch 116 is fashioned with closely spaced, substantially parallel walls 118, as is best shown in FIG. 3; and each notch 116 is selected to take a depth which is appropriate for receiving a piano string 68 therein, the walls 118 of the notch controlling the lateral position of the piano string.

The auxiliary bridge bar 112 is located closely adjacent the bridge bar 98 and is, in addition, situated outside of the space which is defined between the bridge bars 98 and 100. Thus, the auxiliary bridge bar 112 does not contact the piano string along the vibrating span of its length. With the auxiliary bridge bar so positioned, the notches therein have been found to be eminently useful in locating a piano string laterally. Moreover, the auxiliary bridge bar 112 serves to locate the piano string at a position closely adjacent the point thereof which is intended to be struck by the hammer 44. Accordingly, the instant invention assures proper striking of the string by its hammer.

The specific example herein shown and described is to be considered as primarily illustrative. Various changes in structure will, no doubt, occur to those skilled in the art; and such changes are to be understood as forming a part of this invention insofar as they fall within the spirit and scope of the appended claims.

The invention is claimed as follows:

1. In a piano frame arrangement, the combination comprising: a one-piece string plate including a lower frame section and a upper frame section fixedly spaced from said lower frame section; a first elongated bridge bar formed integrally with said lower frame section and adapted to contact transversely and support a plurality of piano strings; a second elongated bridge bar formed integrally with said upper frame section and having spaced notches therein for receiving and laterally locating said strings; and a third elongated bridge bar formed integrally with said upper frame section closely adjacent said second bridge "bar and intermediate said first and second bridge bars for cooperating with said first bridge bar inpositively defining the vibrating span of said piano strings.

2. In a piano frame arrangement, the combination according to claim 1 wherein said bridge bars are of triangular section, said bridge bars being oriented for contacting the piano strings with an apical ridge.

References Qited by the Examiner UNITED STATES PATENTS LEO SMILOW, Primary Examiner.

C. M. OVERBEY, Assistant Examiner.

Claims (1)

1. N A PIANO FRAME ARRANGEMENT, THE COMBINATION COMPRISING: A ONE-PIECE STRING PLATE INCLUDING A LOWER FRAME SECTION AND A UPPER FRAME SECTION FIXEDLY SPACED FROM SAID LOWER FRAME SECTION; A FIXED ELONGATED BRIDGE BAR FORMED INTEGRALLY WITH SAID LOWER FRAME SECTION AND ADAPTED TO CONTACT TRANSVERSELY AND SUPPORT A PLURALITY OF PIANO STRINGS; A SECOND ELONGATED BRIDGE BAR FORMED INTEGRALLY WITH SAID UPPER FRAME SECTION AND HAVING SPACED NOTCHES THEREIN FOR RECEIVING AND LATERALLY LOCATING SAID STRINGS; AND A THIRD ELONGATED BRIDGE BAR FORMED INTEGRALLY WITH SAID UPPER FRAME SECTION CLOSELY ADJACENT SAID SECOND BRIDGE BAR AND INTERMEDIATE SAID FIRST AND SECOND BRIDGE BARS FOR COOPERATING WITH SAID FIRST BRIDGE BAR IN POSITIVELY DEFINING THE VIBRATING SPAN OF SAID PIANO STRINGS.

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