US2474599A - Piano construction - Google Patents

Description

G. H. STAPELY PIANO CONSTRUCTION June 28, 1949.

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June 28, 1949. G. H. STAPELY PIANO CONSTRUCTION 4 Sheets-Sheet 3 Filed Sept. 25, 1944 June 28, 1949. e. H. STAPELY PIANO CONSTRUCTION Filed Sept. 25, 1944 4 Sheets-Sheet 4 Jrraevr? a)? Patented June 28, 1949 PIANO CONSTRUCTION George H. Stapely, South Haven, Mich, assignor to Everett Piano Company, a corporation of Illinois Application September 25, 1944, Serial No. 555,695

6 Claims. 1

This invention relates to an improvement in piano construction, and more particularly to the back or frame construction for an upright piano.

One feature of this invention is that it provides an improved upright or console type piano; another feature of this invention is that it eliminates or minimizes difiiculties heretofore encountered when the piano underwent variations in temperature or humidity or both; yet another feature of this invention is that it substantially completely eliminates bending and distortion of the plate and frame; still another feature 'of this invention is that the forces set up by the strings are counteracted by a frame construction making use of metal posts; a further feature of this invention is that the construction and arrangement is such that the metal posts act as levers about a fulcrum point so located as to provide the maximum opposition to bending of the plate by the forces set up by the tension in the strings; and yet a further feature is that these and other important advantages are achieved in a construction which is not complicated or unduly expensive. Other features and advantages of this invention will be apparent from the following specification and the drawings, in which:

Figure 1 is a front view of a special rectangular plate, with the strings removed; Figure 2 is a back view of a piano embodying my invention; Figure 3 is an end elevation, looking from the left of Figure 2, of the plate and frame assembly with the case removed; Figure 4a is an enlarged partial vertical sectional view of the upper part of the showing of Figure 3; Figure 4b is a partial vertical sectional view of the bottom part of the showing of Figure 3, completing the showing of Figure 4a; Figure 5 is a back view of another form of piano construction embodying my invention; Figure 6 is an end elevation, looking from the left of Figure 5, of the plate and frame assembly with the case removed; Figure 7a is an enlarged partial vertical sectional view of the upper part of the showing of Figure 6; and Figure 7b is a partial vertical sectional view of the bottom part of the showing of Figure 6, completing the showing of Figure 7a.

The strings of a piano extend from tuning pins arranged near the top of the piano to hitch pins located below the tuning pins and at a point determined by the desired length of the string, the tension in the strings being partially withstood by a cast metal plate or harp through which the pins extend. The strings are drawn up, by use of the tuning pins, until they are under considerable tension, to produce the desired notes; and

2 the total forces set up by the tensions in the string assembly ranges between fifteen and eighteen tons in the ordinary upright or console type piano.

It has for years been conventional practice to assist the plate in withstanding this very considerable force by providing an associated frame of fairly heavy wooden members, generally coinprising top and bottom wooden rails, wooden side frame members, and intermediate Vertical wooden posts.

The conventional construction described above has proved to have a number of objections. One of the most noticeable and obvious of these is curvature or distortion both in a vertical and horizontal plane. The forces developed by the tension in the strings are such that theplate and frame tend to bend forward at the top about a point located about one-fourth of the way down the height of the plate, producing the curvature or distortion referred to in a Vertical plane. Moreover, this bending or distortion is accentuated at the treble end of the plate, sothat the variation in vertical distortion also creates a hori zontal distortion or curvature showing bending in a horizontal plane. This distortion would be objectionable enough if it were a static characteristic, but its effects are rendered still more objectionable by the fact that variations in temperature and humidity act differently upon the elements involved (the plate, the strings, and the wooden frame and sounding board), and this results in variations in the distortion which are one of the major factors in the piano losing its tuning.

I have developed and am here disclosing and claiming a piano construction which eliminates all or practically all of the distortion mentioned above, and of the objections incident thereto. I have found that the forces set up by the strings can be properly counteracted by combining with the plate a frame construction incorporating ver= tical back posts, preferably of cast metal, arranged in such a manner that the back posts act as levers about a fulcrum point located at approximatel the point whe're the major bending of the plate forwardly normally takes place. As mentioned above, this is about three-quarters of the way up from the base of the plate, or slightlyhigher.

In the particular embodiment of my invention illustrated in Figures 1-4, inclusive, a plate of a form modified somewhat from conventional construction is identified in general as It; This plate is provided with an upper portion Illa having therethrough two groups of holes or openings,

here identified as iilb on the one hand and Inc on the other hand, adapted to receive the tuning pins, the group shown to the left of the figure receiving the bass string tuning pins and the group of :holes to the right of Figure 1 receiving the tuning pins of the treble strings. The particular plate illustrated is constructed to have the bass strings overlie the treble strings, the hitch pins (not shown) for the bass strings being located in the plate portion Ind and those for the treble strings being located in the plate portion llle.

Behind the plate It is a sounding board I I having glued or otherwise rigidly attached thereto wooden bridge pieces, the bass bridge piece being here identified as I la, and the treble bridge piece as Ho. The strings, after they have passed over these wooden bridge members, would pass over a metal bridge portion, the bass and treble portions being here identified as Hie and If; and,

in accordance with conventional practice, the

treble strings might pass under a metal pressure bar identified as lily. The upper ends of the strings are connected to tuning pins in conventional manner, as the pin l2 which may be best seen in Figure 4a, this pin passing through an opening in the top of the plate Ill and being frictionally gripped in a registering opening in the wrest plank I3. I find it desirable, under certain circumstances, to make the plate ll] with a rectangular outline, as illustrated in Figure 1, although it will be understood that other conventional forms and shapes of plates may be used in practicing my invention.

Referring now more particularly to Figure 2, it will be seen that the back frame construction associated with the plate Ill includes top and bottom wooden rails 14 and i5, wooden side members I6 and I1, and a plurality of vertical posts |8--22, inclusive. The back posts shown are of metal, preferably cast metal to avoid the springiness usually incident to certain other types of metal, and they are flanged and otherwise shaped to provide a maximum of resistance to bending in a vertical plane; although it will be understood that other rigid material and other shapes may be used for the posts.

Referring now more particularly to Figures 4a. and 417, it will be seen that each post (the post l8 being shown) includes a back portion I81: and a forwardly extending web or flange portion I81) perpendicular thereto, the post being formed back or curved in at the point I80 to ensure desired registry with a wooden fulcrum 23 mounted on the wrest plank l3 and extending across the back of the piano about one-fifth of the way down from the top of the frame. The upper end of the metal post is formed with a toe portion, as the portion I8d of the post it, received within a recess in the top rail 14, this rail being rigidly held in desired relation to the top of the plate II] by bolts 24 passing through the plate, wrest plank and top rail at appropriately spaced intervals.

As may be best seen near the lower end of Figure 4a, the post I8 is provided with a boss l8e tapped to receive the end of a. stud 25 providing connection with the plate near the treble hitch pins in each case. Referring now more particularly to Figure 41), it will be seen that the post l8 extends down to terminate in an angularly disposed bottom foot portion [8], this portion lying at an angle of about 15 with respect to the adjacent surface of: the bottom rail l5. In constructing the piano the wrest plank, sounding board, fulcrum member and top, bottom and side rails are assembled. Each post then has its toe portion [8d slipped into the recess in the top rail designed to receive it, the post being fastened to the top rail and the wrest plank, as by the screws shown in Figure 4a. The foot of each post is then brought into proper relation to the bottom rail l5, being forced in slightly toward the soundboard so as to place a tension above the fulcrum point, and is fastened to the bottom rail in a manner to be described. When the plate is adjusted to the frame and the bridges have been planed down to the required height, the studs 25 and 26, etc., are tightened appropriately. The attachment of the foot portion 18f of the post l'8 to the bottom rail 15 involves driving in a Wooden wedge 2"! and then fastening the assembly together by a wood screw passing down through the foot portion and wedge and into the bottom rail. It is desirable to have the entire back assembly tight and rigid, with no gaps, and the use of the wedge 2'! enables this to be effectively accomplished even though the post and frame tolerances are sufficient to permit variations of th of an inch or more.

The soundboard H is of conventional type, with a slight forward curvature, and has the bridges Na and lib glued thereto. The stud bolts connecting to the bosses on the post, as the bolts 25 and 26, pass through openings in the soundboard with sufficient clearance that they have no effect on the soundboard action, this also being conventional. The soundboard must, of course, be dead tight, without so much as a sign of looseness at any time if the piano is to avoid rattles and tinny effects. This is ensured in the construction shown by gluing the soundboard directly to bottom rail [5, side rails it and Il and fulcrum member 23 after these units have been beveled to accommodate the curvature oi the soundboard and notched out to accommodate the soundboard ribs. Still referring more particularly to Figures 4a and 412, it will be seen that the fulcrum member 23 is so formed that its lower portion extends forwardly of the back of the wrest plank and abuts one side of the top edge of the soundboard ll, another wooden liner member 28 being tightly received between the other side of the soundboard and the back of the appropriate portion of plate Hi. The bottom of the soundboard is gripped by the liner member 29 between the appropriate portions of the plate and the face of the soundboard. A side liner arrangement similar to that shown at the bottom is also used at the side between the side members l6 and I1 and the adjacent portions of plate It. The result is that the soundboard is rigidly mounted to the side and bottom rails and fulcrum member which serve as a continuous rectangular frame. Since the coefficients determining expansion and contraction of the material upon changes in temperature and humidity are the same for the soundboard and its frame, the requisite tightness is maintained even though the expansion of the plate and metal back posts may differ from that of the sound-- board.

The most important part of the construction, however, is the arrangement whereby the back posts have a leverage action very greatly increasing their effectiveness in keeping the plate and back structure straight and undistorted despite the forces set up by the tension in the strings. The provision of a portion at the top of each post which toes in under a portion of the top rail, and the connection of the top rail to the top of the' plate not only by gluing but also by the bolts, as 24, ensures maintenance of a predetermined relationship between the top of the post and the top of the plate. The provision of a fulcrum point about three-quarters to fourfifths of the way up from the bottom of the plane, preferably immediately behind or very close to the right-hand end of the bridge portion If on the plate (this fulcrum being provided by the member 23 extending across the back of the bottom edge of the wrest plank in this form of the invention), provides the fulcrum and working points of the leverage system of each post. Very great forward bending forces present at the top of the plate can thus be counteracted by very much greatly reduced holding forces pro-- vided by the connection of the bottom of the post to the bottom rail, and by the. connection of the intermediate stud. bolts, the holding force in each case being multiplied several times in its effectiveness at the top of the plate. The use of cast metal posts of webbed or channelled construction provides sufficiently rigid posts that this leverage action is fully effective, without any appreciable bending or springing of the posts. The result is a back construction which, in ease of construction and in cost, is comparative to the present conventional back construction; that has substantially a conventional appearance, so that there is no consumer sales resistance such as might be occasioned by a freak" construction; and yet which substantially entirely eliminates any distortion of the plate and back, keeps the appearance of the piano better despite long years of use, and ensures the tuning being held much longer than with present conventional construction.

Referring now more particularly to Figures 5, 6 and '7, I will describe another form of piano construction embodying my invention. While this type of construction requires a specially cast plate, rather than making use of the standard plates, it has several advantages. The plate, in front view, might be of present conventional shape or of my preferred rectangular outline as shown in Figure 1, and accordingly a View of the front of the plate is not repeated.

Referring first more particularly to Figures 5 and 6, and using reference numerals on analogous parts 30 higher than those used in the description of the construction shown in Figures 1-4, it will be seen that the plate 40 has a wrest plank 43 attached to the back of the upper part thereof, the plate differing from the conventional plate shown in the earlier figures by having integrally cast backwardly extending top and bottom flange portions 40m and Min. These extend back far enough to abut the ends of the back posts here identified as 48-51. The posts in this case are T-shaped in form, but have the transverse portions, as the portion 48a, toward the front, and the perpendicular flange portions, as the portion 48?), extending backwardly thereon. The top and bottom of each post is connected to the vertical front portion of the plate 40 by through bolts, as the bolts 54 and 62. Wooden side frame members 46 and 4'! are provided, particularly to facilitate fastening of the case to the construction here illustrated. However these side members are unnecessary from a structural standpoint.

Referring now more particularly to Figures 7a and 7b, it will be seen that the soundboard 4| is again held tightly in desired relation to the metal parts by a soundboard frame or liner comprising the top parts 53 and 58 and the bottom parts 58 and 50, similar side liner members (not shown) again being provided to complete a rectangular liner frame. In the particular construction now being described each post, as the post 48, is provided with a small outwardly extending shoulder portion, as the portion 480, this portion being received by a groove provided by chamfering the right-hand corner of the liner member 53 (speaking with respect to the position of the parts as shown in the drawings) and lying immediately under and abutting the lower back edge of the wrest plank i3. This relationship again provides a fulcrum for the posts, the fulcrum in this case being primarily the lower back edge of the wrest plank, although the top part of the liner frame also acts to some extent in this regard. While the bolts at the top of the posts, as the bolt 54, are of sufiicient strength to ensure the desired holding action on the top of the plate, tightness of the assembly may be further assured by the use of wood screws extending through appropriate openings in the posts and into the wrest plank 43, as the screws 63 and 64. One of the particular advantages of tli construction shown here is that the ends of the metal back posts are designed to be received between and abut against the top and bottom plate flanges 40m and 4077,. Since both the posts and plate are cast and of the same material, the tolerances can beheld fairly close and any expansion or contraction is substantially identical.

While I have shown and described certain embodiments of my invention, it is to be understood that it is capable of many modifications. Changes, therefore, in the construction and arrangement may be made without departing from the spirit and scope of the invention as disclosed in the appended claims.

I claim:

1. A piano of the character described, including: a metal plate; strings connected to the front of the plate; a wrest plank connected to the back of the plate at the top thereof; webbed metal back posts, each post having its top portion connected to the top of the wrest plank, an intermediate portion fulcruming at the lower back corner of the wrest plank, and a bottom portion tending to move backward under pull of the strings; and means to fasten each said bottom portion against backward movement.

2. A piano of the character described, including; a metal plate; strings connected to the front of the plate; a wrest plank connected to the back of the plate at the top thereof; a strip extending along the back of the wrest plank at the bottom thereof; a bottom rail; webbed metal back posts, each post having its top portion connected to the top of the wrest plank, an intermediate portion fulcruining on said strip, and a bottom portion adjacent the bottom rail and tending to move backward with substantial force; and means for preventing such backward movement, this means comprising a wedge between the bottom rail and the bottom portion of each back post and in snug engagement with each, each wedge having its narrowest edge toward the front of the piano, and means fastening together the bottom rail, wedge, and bottom of each post.

3. A piano of the character described, including: a metal plate; strings connected to the front of the plate; a wrest plank connected to the back of the plate at the top thereof; a strip extending along the back of the wrest plank at the bottom thereof; a bottom rail; webbed metal back posts, each post having its top portion connected to the top of the wrest plank, an intermediate portion fulcruming on said strip, and a bottom portion adjacent the bottom rail; and a Wedge between the bottom rail and the bottom portion of each back post, each Wedge having its narrowest edge toward the front of the piano and making snug engagement with the bottom rail and the bottom of a back post.

4. A piano of the character described, including: a metal plate; strings connected to the front of the plate; a wrest plank connected to the back of the plate at the top thereof; a strip extending along the back of the wrest plank at the bottom thereof; a bottom rail; webbed metal back posts, each post having its top portion connected to the top of the wrest plank, an intermediate portion fulcruming on said strip, and a bottom portion adjacent the bottom rail; a wedge between the bottom rail and the bottom portion of each back post; and fastening means connecting the bottom portion of each back post to the bottom rail, each wedge having its narrowest edge toward the front of the piano and making snug engagement with the bottom rail and the bottom of a back post.

5. A piano of the character described, including: a metal plate; strings connected to the front of the plate; a wrest plank connected to the plate at the top thereof to provide a top assembly; rigid metal back posts, each post having its top portion connected to the top of the top assembly, an intermediate portion fulcruming at the lower back corner of the wrest plank, and a bottom portion tending to move backward with substantial force under pull of the strings; and means to fasten each said bottom portion against backward movement.

6. A piano of the character described, including: a metal plate; strings connected to the front of the plate; a wrest plank connected to the plate at the top thereof to provide a top assembly; a strip extending along the back of the wrest plank at the bottom thereof; a bottom rail; rigid metal back posts, each post having its top portion connected to the top of the top assembly, an intermediate portion fulcruming at the lower back corner of the wrest plank on said strip, and a bottom portion tending to move backward with substantial force under pull of the strings; and means to fasten each said bottom portion against backward movement, this means including a wedge between the bottom rail and the bottom of the post.

GEORGE H. STAPELY.

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

UNITED STATES PATENTS Number Name Date 57,743 Martin Sept. 4, 1866 100,948 Steck May 15, 1870 464,992 Reed Dec. 15, 1891 1,210,593 Brambach Jan. 2, 1917 1,990,574 Story Feb. 12, 1935 FOREIGN PATENTS Number Country Date 240,180 Great Britain Nov. 4, 1926 499,697 France Nov. 26, 1919

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