US2970507A

US2970507A - Organ reed pipe

Info

Publication number: US2970507A
Application number: US772832A
Authority: US
Inventors: Evelyn M Bolton
Original assignee: AEOLIAN SKINNER ORGAN Co
Current assignee: AEOLIAN SKINNER ORGAN Co; AEOLIAN-SKINNER ORGAN COMPANY Inc
Priority date: 1958-11-10
Filing date: 1958-11-10
Publication date: 1961-02-07
Anticipated expiration: 1978-02-07

Description

Feb. 7, 1961 BOLTON 2,970,507

ORGAN REED PIPE Filed Nov. 10, 1958 United States Patent ORGAN REED PIPE Ralph E. Bolton, deceased, late of Weston, Mass., by

l'ivelyn M. Bolton, administratrix, Weston, Mass., asslgnor to Aeolian-Skinner Organ Company, Inc., South Boston, Mass., a corporation of Massachusetts Filed Nov. 10, 1958, Ser. No. 772,832

Claims. (Cl. 84-350) This invention relates to pipe organs and more particularly to the tone generators adapted to be associated with reed pipes in such musical instruments.

The tone generator in an organ reed pipe is the combination of a shallot having a flat surface with a longitudinal aperture therein and a reed tongue which is positioned over the aperture in this shallot. This reed tongue is a sheet of brass, or other suitable material, which heretofore has been carefully voiced by imparting to that tongue a critical degree of curvature. When the reed is vibrating under influence of a flow of air it rolls down smoothly against the shallot surface. Both the proper curve and the absolute smoothness of that curve are essential in order to produce the desired tone. Should a flat spot occur in the reed by reason of an imperfect curve a harsh and blatant tone will be produced. Thus the proper manufacture of the reed pipe has depended to a substantial extent on the proper voicing or curving of the reed tongue. This is accomplished manually by a voicer who utilizes a burnishing tool and a shaped block of polished steel to impart a smooth curvature to the tongue. This hand voicing operation, in addition to demanding a considerable degree of skill, is a time consuming operation. For example, a full day is commonly required to properly voice a reed tongue for the 32 Contre Bombarde pipe.

Accordingly, it is an object of this invention to provide a reed pipe tone generating element which may be manufactured more inexpensively and by mechanical methods.

Another object of the invention is to provide a tone generator including a shaped shallot which is capable of producing a quality of tone equal or superior to that obtained by the prior art reed voicing method.

A further object of the invention is to produce a more versatile tone generator for the reed pipes.

In the reed pipe according to the preferred embodiment of the invention the tone generator includes the combination of a fiat reed tongue and a shallot which has a cooperating curved surface precisely curved in accordance with a mathematical equation. A simple curve thus may be provided on the shallot surface which cooperates with the reed tongue in a manner to attain a tone generating instrument of the desired quality. Thiscurve of the shallot surface is unique and is not the same curve heretofore imparted to the reed tongue. Among the advantages of the construction is that the tone generators may be manufactured by mechanical methods, thereby increasing production and reducing overall cost. Further the exclusive reliance on the skill of the voicer for this critical step in the manufacture of the reed pipe is eliminated. In addition the proper curvature of the reeds was dependent on the wind pressure whereas in apparatus constructed according to the invention the single curve is correct for a wide variety of wind pressures. A reed pipe utilizing a shallot curved according to the invention also provides a brighter tone than do comparable prior art pipes.

Other objects and advantages of the invention will Patented Feb. 7, 1961 ice 2 be seen as the following description of the preferred embodiment of the invention progresses, in conjunction with the drawing, in which:

Fig. 1 is a view of the reed pipe assembly, in partial section, incorporating the tone generating apparatus according to the preferred embodiment of the invention;

Fig. 2 is a sectional view along the line 2-2 of- Fig. 1; v

Fig. 3 is a top view of the shallot according to the preferred embodiment of the invention;

Fig. 4 is a top view of the reed according to the preferred embodiment of the invention;

Fig. 5 is a sectional side view of the reed and shallot mounted in the block of an organ reed pipe; and

Fig. 6 is a graphical representation of the curve given to the shallot according to the preferred embodiment of the invention.

A view of the assembly of a typical reed pipe for an organ is shown in Fig. l. The assembly includes a horn or resonator 10, a cylindrical or conical structure which may have a variety of shapes and end terminations. A slot 12 of adjustable length or other suitable means is provided near the top of the horn in order that the effective resonating length of the horn may be changed. The lower end of the horn is secured to a block 14 of dense material, such as lead, by suitable means, for example, soldering. This block is bored to provide a pas sageway 16 which communicates with the interior of the horn 10. The configuration of the passageway 16 in the block is shown in Fig. 2.

The sound generating apparatus comprises a shallot 18 and a reed tongue 20. The shallot, shown in Fig. 3, is a tube of brass or other suitable material, open at one end and closed at the other end. There are two principal shapes of the shallot, the French shallot which is a substantially cylindrical tube and has a rounded end, and the English and German shallots, a tapered or conical tube which is closed at one end by a flat plate. Although the invention is not limited to one type of shallot, the shallot which will be described is of the' French type. One surface 22 of the shallot is flattened and a longitudinal aperture 24 is exposed in that surface. This aperture extends from apoint closely adjacent the closed end of the shallot towards the open end.

The reed tongue 20, shown in Fig. 4, is positioned over the aperture 24. There is a relative curvature between the reed and the shallot surface, and the reed, when flexed, is adapted to contact the shallot surface at the edges of the aperture to substantially close the aperture. Heretofore the reed tongue 26 has been curved, or voiced, substantially as shown by the dotted line in Fig. 5, and has cooperated with a straight shallot surface.

The shallot 18 and reed tongue 20 are mounted together and inserted into the passageway 16 by press-fit. A wedge 26 is inserted into the slot 28 provided in the passageway 16 to positively secure the reed tongue in position. A tuning rod 30 passes through the aperture 32 in block 14 and has a tip end 34 which is adapted to contact the reed tongue. The rod 30 may be adjusted longitudinally of the tongue, thereby aifording control of the eifective vibrating length of the tongue.

A boot 36, commonly manufactured of zinc, pipe metal, or wood, is inserted over the positioned shallot and tongue and is secured to the block 14 by cooperation of the conforming tapered surfaces thereof. The boot has an aperture 38 in its lower end through which air is admitted as desired. Sound is produced by passing air across the reed tongue 20 and through the aperture 24 and the shallot. The pressure differential on the reed tongue tends to cause it to roll smoothly down the shallot surface substantially closing the aperture and changing the pressure differential. The tongue then tends to return toward and past its initial position and the action is repeated alternately to close and open the aperture. This movement of the tongue in cooperation with the shallot generates the desired tone, which tone isthen amplified and modified by the resonator.

The organ pipe according to the invention includes a shallot in which the surface adjacent aperture 24 is curved rather than straight. In the preferred embodiment, a flat unvoiced reed tongue 20 cooperates with this surface. The curve of the shallot surface is distinct from the curve heretofore imparted to the reed by the voicer in an exacting and time consuming operation. That curve heretofore has been obtained by a manual operation with complete reliance on the skill and the ear of the artisan. The dimensions of that curve were not of concern to the voicers. In contrast, the shallot surface, provided in accordance with the inventIon, is a precise curve which is described with substantial accuracy by the following exponential equation:

substantially as is shown in Fig. 6. Shallots curved in accordance with this equation, in cooperation with flat reeds, produce ideal tones for the chorus reeds in the 32 foot Contre Bombarde series, for example. Modification of that curve, as defined by the equation:

specifies a lower limit of acceptability and the following equation defines an upper limit of acceptability:

These equations define the curve of the shallot surface between X and S where S is the length of the shallot. In these equations L is the length of the pipe. Along the shallot surface from X equal to 0 (the open end of the shallot) to X equal to X Y equals 0. Thus the curve of the shallot surface is the combination of a straight line and an exponential curve. While the constant X varies somewhat it is generally approximately equal to It is to be noted that the curved plane surface of the shallot produces an aperture not of constant width, but of increasing width toward the closed end of the shallot. The shallot surface may be easily, quickly and accurately shaped in accordance with this equation in an appropriately controlled mechanical grinding operation. A slight amount of hand finishing is sometimes desirable in order to obtain the exact tone color sought for the particular application of the organ in which the reed pipe is used.

Thus the invention provides an improved organ reed pipe which may be built in accordance with certain modern manufacturing techniques, more rapidly and at significantly reduced cost. The pipe constructed according to the invention produces a tone equal, if not superior, in tone quality to the best prior art pipe. The invention, in addition, provides a construction which is substantially more versatile than those heretofore used in the pipe organ art.

While the preferred embodiment of the invention has i been shown and described it will be understood that the invention is not intended to be limited thereto or to details thereof and departures may be made therefrom within the spirit and scope of the invention as defined in the claims.

Whatis claimed is:

1. In an organ reed pipe, a sound generating apparatus comprising a reed tongue adapted to be vibrated by air pressure, and a shallot open at one end and having a longitudinal aperture cut through a'portion of the wall thereof, said aperture having edge portions which define a smothly curved plane surface, the curve of said surface being defined by the equation:

said reed tongue being adapted to be secured in position relative to said surface such that it overlies the edge portions of said aperture and is adapted to roll down smooth- 1y into progressive abutment with said edge portions when it is vibrated.

2. The apparatus as claimed in claim 1 wherein said shallot is a tube closed at one end and said aperture is positioned in a curved plane surface portion of said shallot, said surface portion being curved smoothly along the length of the shallot such that it approaches the axis of the shallot adjacent the closed end thereof.

3. The apparatus as claimed in claim 1 wherein said reed tongue is a substantially flat flexible member.

4. An organ reed pipe having a musical tone generator comprising a vibratory reed tongue, a shallot having a closed end, an open end and an interior passageway, said shallot being substantially circular in cross-section but with a portion of said cross-section defining a flat surface adapted to receive said reed tongue in cooperating relationship, said surface being formed in a plane curve which approaches the axis of the shallot adjacent said closed end, and having an aperture in said surface such that communication is provided from outside said shallot and means to position said reed tongue on said surface such that it tends to roll down smoothly against said surface under the influence of air pressure to control the flow of air through the said passageway to produce the desired tone. 7

5. The organ reed pipe as claimed in claim 4 wherein the curve of said surface is defined by the equation:

References Cited in the file of this patent UNITED STATES PATENTS 357,469 Davis Feb. 8, 1887 795,493 Ditto July 25, 1905 1,323,436 Austin Dec. 2, 1919 1,363,580 Fletcher Dec. 28, 1920