US2554665A

US2554665A - Fall board mechanism

Info

Publication number: US2554665A
Application number: US115076A
Authority: US
Inventors: Wilbur M Day
Original assignee: BALDWIN CO
Current assignee: BALDWIN Co
Priority date: 1949-09-10
Filing date: 1949-09-10
Publication date: 1951-05-29
Anticipated expiration: 1968-05-29

Description

May 29, 1951 w, M DAY 2,554,665

FALL BOARD MECHANISM Filed Sept. l0, 1949 Bg @www Gttornegs.

Patented May 29, 1951 FALL BOARD MECHNISM Wilbur M. Day, Kenwood, Ohio, assignor to The Baldwin Company, Cincinnati, Ohio, a corporation of Ohio Application September 10, 1949, Serial No. 115,076

9 Claims.

My invention relates primarily to that type of fall board construction in musical instruments `wherein a fall board, covering a keyboard or keyboards, lies in the covering position at a downward slant or tilt. When the fall board is moved to uncover the keys, it is first raised manually to a substantially horizontal position, after which it is pushed rearwardly into the case of the instrument, the ends of the fall board sliding on substantially horizontal rails or their equivalent. A primary object of the invention is the provision of an effective and operative equalizing mechanism for such a fall board.

An equalizer in this art is usually a U-shaped metal member of substantially the same length as the fall board, the base of the U being pivoted effectively to the inner edge of the fall board, while the arms of the U extend away therefrom and are pivoted elsewhere at or near their ends. The purpose of the equalizer is to prevent cocking of the fall board as it is moved between the opened and closed positions, and hence to provide for easy operation of the fall board irrespective of the position of engagement of the operators hand or hands therewith. A cooking of the fall board would lead to jamming and sticking. A properly equalized fall board will move easily and freely along the guides throughout its traverse even though the moving force be applied to it at one end only. A properly operative equalizer mechanism causes motion of the fall board at one end to be reflected in substantially equal motion in the same direction at the other end, for the purpose described.

The problem of equalizing a fallboard of this type is a complicated one due to the horizontal or planar movement of the rear edge of the fall board. Because of this, the ends of the equalizer arm-s cannot be pivoted at xed positions on the end frame elements of the instrument case. Various expedients have been suggested. For example, it has been suggested to substitute racks for the substantially horizontal guides, and to replace the U-shaped equalizer with a shaft paralleling the rear edge of the fall board and bearing spur gears at each end meshing respectively with the racks. Such a construction is, however, both costly and noisy. Other suggestions have been made contemplating what amounts to a pair of opposed equalizers, one pivoted to the fall board and the other pivoted to the frame of the instrument. Such a construction is highly disadvantageous because the second equalizer invo1ves a rod, if not a. panel, extending across the instrument inside the case and occupying space required for other instrum-entalities, such as the elements of a piano action, by way of example. Finally, it has been proposed to pivot the ends of the equalizer arms to the upper ends of elongated link members which, extending downwardly, are pivoted at their lower ends to the side frame members of the instrument case. This provides moving pivot points for the ends of the equalizer arms, the pivot points moving rearwardly with the fall board as it is traversed from closed to open position. This, however, does not provide effective equalization for the reason that a linkage system arranged in this manner does not prevent that cooking of the fall board which the equalizer is primarily intended to prevent.

An important object of the invention is the provision of an equalizer mechanism wherein the arms of" the equalizer have movable pivots permitting a planar traverse of the base of the equalizer, but wherein a linkage system providing the movable pivots is effective in enabling the equalizer to prevent cooking of the fall board.

With the above objects in mind, it is a further object of the invention to provide a fall board mechanism which is inexpensive and simple in character.

These and other objects of the invention which will be set forth hereinafter or will be apparent to one skilled in the art upon reading these specications, I accomplish by that certain arrangement of parts of which I shall now describe exemplary embodiments relating to two diierent types of keyboard instruments. in the accompanying drawings, to which reference is now made, the specific design of the instrument case and the fall board does not constitute a limitation on the invention. Consequently, a transverse section through the musical instrument sufficiently illustrates the nature Bf my construction and mechanism.

Figure l is such a section of a piano as exemplifying one type of musical instrument, and

Figure 2 is a similar section through a twomanual organ as exemplary of another type of keyboard musical instrument.

In Figure l I have shown a piano having end case or frame members, one of which is shown at I. The top board or cover of the instrument is shown at 2A The key bed 3 is surmounted by a key frame i on which a plurality of keys 5 constituting the keyboard of the instrument are pivoted in the conventional way. There is a key slip 6 at the front of the keyboard. The front board 1 of the instrument supports a desk element bearing a music rack 9. lies at the rear of the keyboard.

The fall board II is shown in solid lines in closed position. It has a width lfrom iront to rear sufcient to overlie the keyboard with its rear edge extending under the desk element 8 as shown. Its front edge may be provided with a lip I2. In the closed position the fall board has a forward and downward slant as shown.

When it is desired to move the fall board from the closed to the open position, the front portion of it is grasped and the fall board raised to a substantially horizontal plane. It is usual though not necessary to provide on the lip I2 one or more operating knobs I3 for the hand or hands of the operator. When the fall board has been raised to the substantially horizontal position, it is then manually moved rearwardly beneath the desk element S, the end edges of the fall board sliding on guide members affixed to the end frame elements I of the case. One of these guide members is shown at Iii. Its upper sur-face may be covered with felt or other cushioning means.

The equalizer mechanism comprises a U- shaped, metal equalizer element, the base of the U being indicated at I5, and lshown pivoted to the rear edge oi the fall board I I by hinging eloments I6. The arms of the U-shaped equalizer extend generally downward in all positions. One of these arms is shown at Il, it being understood that there is an arm of similar construction at either end of the base of the U. Each arm Il is pivoted at its rearward and downward end as at I8 to a relatively shorter link element I9. This element has a xed pivot 2t which may be either on the end frame elements I of the instrument casing or on a fixed element attached thereto. In the particular piano construction I provide for convenience in attachment a pivoting element 2l which is attached to the end frame member of the instrument casing by screws 22 in an immovable position. This is dictated by the presence of action elements generally indicated at 23 between the end frame elements of the casing.

It will be noted that by the use of the links I9 instead of a second opposed equalizer mechanism, there are no parts of the equalizer device A finish strip II) extending' across between the end frame elements of the casing below the fall board proper, which avoids interference with the action elements 23 or abstract elements 24.

The position of the fall board in Figure l is .shown open in dotted lines. It will be seen that the fall board lies substantially horizontal, and that the front lip I2 coacts with the finish strip I to close the iront part of the instrument casing, while exposing the key bed for playing purposes.

The manner'in which the fall board equalizing mechanism'operates will be described in connection with Figure 2 which shows a modified type of instrument requiring a somewhat modified fall board, but employs the same equalizer structure.

Figure 2 shows a two-manual organ of which an end casing element is indicated at 25. This instrument has an upper keyboard 26 and a lower keyboard 21, appropriately mounted. The fall board 28, since it must cover both of these keyboards must of necessity be wider than the fall board of the instrument of Figure l. It has a front lip 29. In the closed position it lies aslant downwardly, as shown, at a greater angle.

It is convenient in this instance to pivot the board strip 30 by means of hinging elements 3E.

The ends of the arms 3f: of the equalizer are pivoted as at 31 to link elements 38. These lin.; elements at their opposite ends are pivoted as at 39 to blocks lo attached directly to the end frame elements 25 of the organ console.

Again, 'the fall board has been shown in dotted lines in the open position. In Figure 2 I have illustrated the mode of operation of the fall board equalizer mechanism. When the fall board is in the closed position, as shown in solid lines in the gure, the equalizer arm 36 slants downwardly and rearwardly at a substantial angle to the horizontal. The movable pivot point of the arm 3d is at the position indicated at 31. As the fall board and fall board supplementary strip are moved rearwardly, the movable pivot points of the arms of the equalizer move downwardly so that, when the equalizei1 arms occupy a position indicated at 4I in a dot-dash line, which position is vertical and is occupied at about the mid-point of the traverse of the fall board, the movable pivot point will have moved downwardly to a position indicated at 42. As the traverse of the fall board and fall board supplementary strip continue in the rearward direction, the movable pivot points for the equalizer arms 3l will begin to rise again so that, when the fall board has been pushed to its fully opened position, the equalizer arms will lie along the dot-dash line tilting downwardly and forwardly at very nearly the same angle to the horizontal as was formed by their downward and rearward tilt in the position 3E, and the movable pivot point will lie in a position ifi which is very close to the position indicated by the numeral 3l. The exact traverse of the several elements will depend upon the width of the fall board and hence the extent or' its forward and rearward movement, the presence or absence of a fall board supplementary strip 30, the specific lengths of the equalizer arms I7 0r 36 and of the links I9 or 38. But it will `be noted that in both of the embodiments of my invention, while the angularities of the arms in the forward and rear positions may or may not be substantially equal, and while the movable pivot points may or may not occupy substantially the same positions in the fully opened and fully closed positions of the fall board, nevertheless the following relationships obtain:

1. The links are always substantially shorter than the eouaiizer arms.

2. 'Ihat the links swing from positions above a horizontal plane to positions therebelow, while the equalizer arms swing from positions at one side of a vertical plane to positions at the other side thereof, and

3. While the base of the U-shaped equalizer traverses substantially a horizontal plane, the pivot' points oi the ends oi the arms of the equalizer traverse paths which, while actually arcuate, are almost directly toward and away from the first mentioned horizontal plane, so

that they may roughly be described as dening a plane which is substantially perpendicular to the plane described by the base of the equalizer.

When the equalizer mechanism is arranged as has been set forth, the equalizing action is excellent because the forces directed against the moving pivot points of the equalizer arms are at all times in such direction as to produce eiective equalization, and cocking of the fall board is effectively controlled.

Modiiications may be made in my invention without departing from the spirit of it. Having thus described my invention in an exemplary embodiment, what I claim as new and desire to secure by Letters Patent is:

1. In combination in a musical instrument, a case having two end frame members, at least one keyboard disposed substantially horizontally between said end frame members, a fall board having a covering and uncovering position with respect to said keyboard, substantially horizontal slides for said fall board fixed with respect to said end frame members, and on which end edges of said fall board may slide during traverse between said covering and uncovering positions, and an equalizing mechanism comprising a U- shaped member having a base pivoted to said fall board adjacent the end edge thereof, arms projecting at the ends of said U-shaped member,

and means providing movable pivots for the ends f of said arms, said means comprising link elements providing an up and down traverse for said movable pivot points, while said link elements pivoted elsewhere at xed positions with respect to said end frame elements, are disposed at a sufficiently great angle to the vertical to resist thrust on said movable pivot points in substantially horizontal directions.

2. The structure claimed in claim 1 wherein said arms extend downwardly from the base of said U-shaped member, and wherein said links extend rearwardly from said movable pivot points.

3. The structure claimed in claim 2 wherein said links are of substantially lesser length than Said arms.

4. The structure claimed in claim 3 wherein said fall board is pivoted to a supplementary fall board strip at its rear edge, and wherein the base of said U-shaped member is pivoted to the free rear edge of said supplementary strip.

5. In a musical instrument, a fall board slidable substantially horizontally on fixed guides, and an equalizer mechanism comprising a U- shaped member having a base and arms, the base of which member is effectively pivoted to the rear edge of said fall board, the arms of which member extend downwardly in substantial parallelism, links having xed pivots spaced from said rst mentioned pivots, the ends of said arms being pivoted to said links, the angularity of the said links to a horizontal plane being, in all fall board positions, less than the angularity of said arms to the same plane.

6. The structure claimed in claim 5 wherein said links in all positions extend rearwardly of their pivotal connections to said arms.

'7. In combination in a musical instrument, a case having two end frame members, at least one keyboard disposed substantially horizontally between said end frame members, a fall board having a covering and uncovering position with respect to said keyboard, a slide for said fall board xed with respect to said end frame men bers, an equalizing mechanism comprising a U- shaped member having a base with two arms projecting therefrom, said base being pivotally connected with the rear edge of said fall board, and link members each having one end pivotally related in a xed position to said end frame 'members and another end pivotally connected to one of said arms, the pivotal connections with said end frame members causing the remaining pivotal connections of said links to follow an arcuate path as determined by said arms in the traverse of said fall board between covering and uncovering positions, the extreme ends of said arcuate path dening a pla-ne which is substantially perpendicular to a plane described by the base of said equalizer when said fall board is moved between covering and uncovering positions.

8. In a musical instrument, an equalizer mechanism for a fall board having a rear end guided for substantially horizontal movement with respect to a iixed case, said equalizer mechanism comprising a U-shaped member having arms extending from a base pivoted to the said rear end of the fall board, and two links pivoted with respect to said case, said links having respective pivotal connections with said arms, the path described by said pivotal connections during movement of said fall 4board being substantially vertical.

9. In a musical instrument, an equalizer mechanism for a fall board having a rear end guided for substantially horizontal movement with respect to a iixed case, said equalizer mechanism comprising a U-shaped member having arms extending from a base pivoted to the said rear end of the fall board, said arms in all positions of the fall board extending at a substantial angle to the horizontal, and movable pivot means for the ends of said arms with respect to the case, said movable pivot means having movement substantially in a vertical direction, and being resistive to movement in a substantially horizontal direction.

WILBUR M. DAY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,242,952 La Joie Oct. 16, 1917 2,178,565 Day Nov. 7, 1939