US3204508A - Piano plates - Google Patents

Description

P 7, 1965 c. ULTES, JR 3,204,508

PIANO PLATES Filed April 4, 1960 FIG-1'3? "a,

INVENTOR. CARL ULTES,JR.

ATTORNEYS United States Patent 3,204,508 PIANO PLATES Carl Ultes, Jr., Springfield, Ohio, assignor to 0. S. Kelly Company, Springfield, Ohio, a corporationof ohio Filed Apr. 4, 1960, Ser. No. 19,820' 7 Claims. (Cl. 84-188) This invention relates to piano, plates, particularlyto improved piano plate constructions incorporating :integrally formed hitch pins, guide pins, agraffes, and/or hearing surfaces.

Apiano plate, upon and over whichthe pianoistrings are strung in tension, requires various desirable properties .which are, in a sense, inconsistent. One requirement is that of high vibration damping capacities, so that the plate'will not vibrate in resonance with the strings. While various materials have been, at one time'or another,.em- "ployed for this-purpose, theartrformany years has found thatcastings of gray cast iron maybe formed which'have 'high damping capacity while in addition providingithe necessaryustrength .for supporting the highloads exerted thereon due to tensioning of the many strings of the plane.

This tensiouing maybe non+uniform, being adjusted by the tuner, since .the proper tuning of a string -or.strings which sounds a particular note :is determined by tension and mass,.in cooperation with .a' fixed elength (variable .between strings) which is known 'astthe speaking length of the string. Obviously, .once thepianolis properly-tuned there may be highertensions in .various strings with respect'to other'strings.

The strings are supported directly .by the plate, which .may receive'tuning pins inJa predetermined section thereof. In the case of upright pianos, the tuning pins generally are placed at the top of the plate for accessibility to the tuner, who. mustmanipulate'the tuning pins while at the same time strikingthe keys. For essentiallythesarne xreason the tuning pins in .grand piano plates, mounted generally horizontal, are usually .all located .toward the section of the plate located to theifront of thepiano. The ends of the strings are suitably fastened'to the tuning .pins, andmay passiaround or "throughagrafles :or guide pins in the plate which serve'to locate the strings with respect *to each other. The strings also may pass-over bearing surfaces or beads atthe top andbottom (or-'front and back in the case of grand plates) :and beyond the bottom bearing the strings tpassaroundor are -secured'to hitch pins :which provide a fixed anchorage therefor.

Asis wellknown, the majority of the notes' of a piano are formed of two or three extents of .astringrfromtop to.bottom, whilea minority of the notes,.essentially in the lower.bass section, are formed .ofheavier strings which extend only fromttop to bottom, withoutrreturn. Thus,.in

three-string note 'sections'a'given stringmay be fastenedat one of its endsto a' tuning pin,'hooked.around a'hitch pin at the lower section of the 'plate, and passed upwardly to another-tuning'pin to which its opposite endi's secured.

Therefore, the one piece of string wireactually viforms two strings of thepiano, and these strings mayor may notbe in the same note.

'It'has been customary .to'provide agraffes, guide' pins and hitch.pins.asseparate'individual pins, usually of steel, which are driveninto individualholesformed inrthe p'late, and may be bent topredeterminediangles in accordance with'theirdesired function. When it is realized that-the standard piano has eighty-eight notes,.and that many'of 'these notes 'arecomprised of two 'orithree strings, it will be appreciated that the drilling of :all the holes in'the plate .to 1 receive agralfe :and hitch pins, together with the fitting, placing, and :proper bending of pins, represents considerable time and cost in the manufacture of piano plates.

Patented Sept. 7, 1965 :More important, the projecting steel pins, particularly ,the hitch pins are required to provide a fixed anchorage .fortthei-stringa-but often whenstring tension is applied in tuningthese .pins bend, to a certain extent initially, but -also,gradually under string tension, with'the resultthat lthe piano does 'notstayin'tune. Furthermore, it is pos- 'sible.forsuchinsertedgpinsto workzloose dueto the effects or time, temperature changes (with the pins-andthe plates having .different coeificients .of thermal expansion), and .coupled wwith'the effects of vibration during playing of ithe usual ;practice is to drill the holes as noted above,

using a. jig to .loc-ate some of the many holes for those steeLpins. In production, more than one jig may be used, vandit is' likely that the spacingofholes asbetween differentjigs :may vary somewhatin spite of allefforts to maintain uniformity. Also, the jigs will wear and contributerthus to g-poss'ible slight misalignment-of the'holes. Ifthe hitch.pins, guide-.pins, agraffes, etc., are formed integrally with the plate, superior control ofplacernent is readily achieved.

.-As ;-previously noted, the plate itselfshould :have high vibration damping capacity, and a most desirable mate- .rial for this purpose, .whichtalso provides the .requisite strength, is. agray'castiron. This material in relatively largetcaStings will'cool. slowly when cast, with a resultant =cast;plate which has the desired'vibration.absorbing characteristics. 0n .the other hand, small-protuberances or "projections from the :casting, if properly designed, may cool at a higher rate than the main body of the casting with a resultant harder surface. It is generally known that cast .ironis harder-than-the low carbon steels normally used for pins of thisitype. .In this regard, hardness is considered to mean resistance to surface impression, for example, as-determined by the well known Brinnel test. And in overallstrength in compression, cast iron is generally superior to steels.

Cast inpinssuch as providedby'this invention can be made considerably stronger and more rigidthan the in- -serted steel pins. Basically, the reason forthisresides in the :freedom ofdesign .o'f'castlinpins which-is not available with inserted pins. A typical cold rolled steel pin will be of circular cross section, which is the logical design for mass production, since large quantities of the pins are used and they must be vdriven into-holes in the :plate. :Pins and.=holes ofirregular cross section obviously would createmanufacturingand insertion "problems, both as to themanufacture ofthe-pins'and lIhCzCl'CfltlOll of com- ,plementary holes in:the plate, which far outweight whatever advantages might be .gained by such arrangements.

However, a cast in pin can be made of teardrop shape,-extending=along thesurface ofthe plate, for example, in theadirection'inwhich the: strings'areplaced or strung. Thus, essentially 'all of the :cast in pins can be in essentially compression loading-When the strings are placed andtightened:or.tensioned,cand.cast iron in com :pression is stronger than mild steels.

Another disadvantage 'of :presently used inserted hitch spins concernsthe very process by which 'these pinsare placed in holes in the piano plate. These pins are bent "to the .proper angle, bent over in a-direction-opposite to the extent of the strings, after they are inserted into the holes in the plate. This sequence of steps is necessary since the pins must be driven into place for a tight fit, and thus cannot be bent previously. The bending tool cannot produce a bend immediately at the surface of the plate, and therefore there is a slight segmentof the pin adjacent the plate surface which is not formed to the proper angle, and the strings under tension can tend to slide or ride up the pin, away from the plate surface. many plate constructions this may result in a change in the bearing of the strings upon their bearing surfaces, and also in string tension.

Accordingly, the primary object of this invention is to provide a novel piano plate construction which includes integral hitch pins, guide pins, agraffe, and/or bearing surface elements which, by reason of their integral formation with the plate itself, overcome the objectionable features of separate inserted hitch pins and agraffe constructions, as noted above.

Another object of this invention is to provide such a novel piano plate construction which is by reason of its integral design inherently less expensive to manufacture. An additional object of the invention'is to provide a gray cast iron piano plate including integral projections (formed from the string mounting sections thereof) serving as hitch pins, guide pins, and/or agralfes, and in which such projections have surfaces of substantially greater hardness than the remainder of the mild casting.

A further object of the invention is to provide an improved hitch pin construction for piano plates in which a firm positive anchorage for the strings is provided, and in which the string looped about the hitch pin is maintained as close as possible to the surface of the plate, and thus maintained properly in contact with the bearing surfaces.

Another object of the invention is to provide a novel piano plate construction incorporating integrally formed string bearing surfaces which extend'substantially perpendicular to the direction in which strings are placed' over such surfaces, and in which separate such bearing surfaces are provided for engaging only those strings forming a single note, thereby assuring that the speaking length of different strings forming the same note is essentially the same.

Other objects and advantages of the invention will be apparent from the following description, the accompany ing drawings and the appended claims.

In the drawings- FIG. 1 is an elevational view of a piano plate in ac-' cordance with the invention, including portions of some of the strings to show the general placement thereof;

FIG. 2 is a detail view on an enlarged scale of the upper left corner of FIG. 1;

FIG. 3 is a partial enlarged perspective detail, showing a portion of FIG. 2, and emphasizing the novel agraffe and bearing surface constructions provided by this invention;

FIG. 4 is a partial sectional view on an enlarged scale, 7

FIGS. 6, 7 and 8 are partial sectional views, similar to FIG. 4, illustrating modified forms of hitch pin constructions.

Referring to the drawing, which illustrates some preferred embodiments of the invention, FIG. 1 is an overall view of a so-called overstrung plate for an upright It should be understood, however, that- ;0

r is applied, will be held against the surface of the mount- ..ingsection 12, as shown particularly in FIG.4, and there will not be any tendency for the string to ride up this type of piano. this particular type of plate is described merely for purposes of explanation, and that the features of this invention may be applied to other plates, for example plates for grand pianos which may or may not be overstrung,

and which are normally mounted in a horizontal plane.

The plate is formed as an integral casting of gray cast iron and includes an upper string mounting section 10 and lower string mounting sections "12 "and 14. These sections are joined by cross bars 15, 16, 17 and 18 which provide the necessary top to bottom strength and rigidity, while leaving relatively large apertures through the plate, thereby reducing the weight theerof.

The main set of strings, some of which are shown at 20, extends from the upper mounting section 10 to the lower mounting section 12, while the longer strings, a few of which are indicated at 22, particularly the bass section extend from the upper section 10 to the lower section 14, passing over the main strings 20 intermediate their lengths. Hence, this type of string mounting and this type of plate is generally known as an overstrung construction. In the upper mounting section 10 there are formed a plurality of apertures 25 which receive tuning pins 27 (FIGS. 2 and 3) mounted in suitable bushings (not shown) and about which ends of the wire strings are engaged and wrapped.

The strings extend from one tuning pin downwardly and around hitch pin members indicated generally at 30, on the lower section 12, and thence back again to another tuning pin. In passing from the tuning pins the strings engage over a bearing surface or head 32 which may be conveniently formed as an integral inverted V-shaped bead projecting from the plate, and likewise -in the lower sections 12 and 14 the strings pass over and in engagement with a bearing surface which may be 'formed by an integral head 33 projecting from the surface of the string mounting section 12.

The strings 22, which are the heavier bass strings, are also engaged in appropriate tuning pins 27 and hooked around hitch pins 30 formed in the lower mounting section 14. The bass notes provided by the strings 22 may .be formed by single strings, in which case a loop is formed in known manner at the lower end of the strings and hooked over the appropriate hitch pin.

In such construction, and referring particularly to FIG. 2, the tuning pins are generally offset somewhat from the path along which the strings extend, particularly in the bass section, and before passing over the bearing surfaces, indicated by the general reference numeral 35, these strings are engaged around agraifes 38 which serve to position the strings in proper alignmentand redirect them over the bearing surface toward the lower mounting section 14.

In this-lower note section particularly, where there are notes formed by more than one string, the distance between the bearing surface and the wood bridge, which .engages with the strings and the sounding board, may

vary somewhat between strings of the same note, due

to'the angular direction of the upper mounting surface with respect to the path in which the strings are placed.

In accordance with the invention the multi-string notes may be provided with individual bearing surfaces, in the form of individual ridge-like projections 40 which extend essentially perpendicular to the strings, and which are of such length that they engage only those strings common to a particular note.

The hitch pin construction in accordance with this invention is shown in detail in FIGS. 4 and 5 as including integral projections from the lower string mounting sections 12m 14, of any suitable shape, and including a back or string'engaging surface 45 which extends out- ,wardly of the plate and at an angle away from the direction in which the strings extend. 'By forming these hitch pin members as integral parts of the gray cast iron plate the angle of this surface 45 may be such, particu- 1 larly at the juncture of the hitch pin member with the main surface of the plate, that the string, when tension surface.

Furthermore, by reason of the relatively small size of these 'protuberances or projections forming the hitch pin members, and also the agratfes and bearing surfaces, they will become chilled and hardened when the plate is cast, whereas the heavier areas (i.e. the major portion) of the plate cool more slowly and provide the desired high vibrational damping capacity. The hardened surfaces of the hit-ch pin members 30, agratfes 38, and the various bearing surfaces, provide desirable wear resistant characteristics and particularly are capable of resisting the high local pressures exerted thereon by the strings when tensioned, substantially preventingembedding of the strings in such surfaces.

FIGS. 6 and 7 illustrate other embodiments of hitch pin constructions which may be provided in accordance with the invention. In FIG. 6 the hitch pin members 30a include a depression or well-like construction 50, at

their base, which receive the lower end or turn in the string a as it passes over the slanted or inclined lower hitch pin surface 45a. In FIG. 7 the hitch pin member or projection 30b is formed from the lower edge of a plate mounting section 12b, projecting essentially parallel to the surface plane of the plate, rather than essentially transversely thereto as in the previously described constructions. In this embodiment the string 20b passes over the edge of the plate section 12b and around the hitch pin member 3011.

FIG. 8 shows a further embodiment of the novel hitch pin construction. Here, the plate section 120 may include a bearing surface or bead 33c, and beyond this bearing surface a hole or holes 130 are provided in the plate casting. The hitch pin members 300 are cast on the back surface of the plate section 120 beyond these holes, and the strings, one of which is shown at 20c, pass over the bearing surface, through the hole 130 to the opposite or rear face of the plate, and into engagement with the hitch pin 30c, passing therearound, or being hitched thereto, as the case may be. Of course, with this construction it is possible to eliminate the bearing bead 330, if desired, since the strings are positively guided into engagement with a surface or edge of the plate in passage through the hole 136.

It should be understood that the above described parts, particularly the hitch pin members, are of variable width, and need not all be of essentially the same width as indicated for example in FIG. 5. Thus, taking the case of three string notes, which are used primarily in the treble section, one string may provide the lowest (in pitch) string of one note and the highest string of the next lower note. In order to space these strings apart somewhat over the plate, to direct the strings properly to the sound board bridge and to accommodate engagement of the strings with the hammers of the respective notes, it may be desirable to widen the hitch pin projection to accommodate such spacing. In constructions heretofore known, if such spacing were desired, a pair of adjacent hitch pins would be needed to form this required spacing.

From the foregoing description, it will be apparent that the present invention provides a novel piano plate construction which incorporates all of the desirable features of strength and high vibration damping capacity, while at the same time eliminating the inserted hitch pins, guide pins, and agratfe pins which heretofore had be be placed individually within separate holes drilled in the plate. By forming such parts integrally with the plate, all tendencies of such pins to loosen, with resultant loss of tune and/ or buzzing, misalignment of strings, etc., is avoided. Furthermore, the present invention provides for consistency and accuracy of alignment of the hitch pins, guide pins, agraffes, etc. There are no inserted pins to twist or bend, with resultant misalignment or misguidings of the strings. The use of a jig to locate the drill for pin receiving holes is eliminated, and the novel guide pins, hitch pins, etc., provided by this invention may be formed directly in the mold when the plate is cast. Heretofore, after some use the holes in such jig plates would tend to wear, with con sequent possible misguiding of the drill, and slight misplacement of the hitch pin holes, etc. At the same time, by reason of the elimination of the drilling and pin setting and inserting steps of manufacture, the cost of manufacture is reduced considerably.

While the forms of apparatus herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise forms of apparatus, and that changes may be made therein without departing from the scope of the invention as defined in the appended claims.

What is claimed is:

1. A gray cast iron piano plate comprising an integral casting having upper and lower string mounting sections joined by cross members and defining therewith a body on one face of which strings are adapted to be mounted under substantial tension, socket means in said upper string mounting section for receiving tuning pins to which the ends of strings are adapted to be attached and around which the strings are pulled for tensioning and tuning, and pin and agratfe members formed as integral projections from surfaces of said mounting sections over which strings are passed, said pin and agratfe members being cast in their final form and arranged at predetermined spaced locations aligned with said tuning pin socket means forming guide and/or anchorage elements about which the strings may be engaged and maintained in predetermined alignment under substantial tension, said pin and agraife members having surface portions which are harder than the remaining surface of said plate to resist imbedding of the strings therein.

2. A piano plate comprising an integral casting having spaced apart string mounting sections joined by cross members and defining therewith a rigid body over which strings are adapted to be mounted, socket means in said upper string mounting section for receiving tuning pins towhich the ends of strings are attached and around which the strings are pulled for tensioning and tuning, and hitch pin and agraffe members formed as relatively narrow integral projections from surfaces of said mounting sections over which strings are passed, said pin and agraffe members being arranged at spaced locations aligned with said tuning pin socket means forming guide and/or anchorage elements about which the strings may be engaged and maintained in predetermined alignment, and said pin and agraffe members being cast in their final form obtaining greater surface hardness than the major portions of said casting to resist embedding of the strings therein under the normal substantial tensions applied to the strings.

3. A piano plate of the character described comprising a unitary casting of metal which provides a high vibration damping capacity and which has sufficient strength to resist relatively great forces exerted by mounting of strings under substantial tension from the top to the bottom across one face thereof, said casting including upper and lower string mounting sections between which the piano strings are extended, reinforcing cross members extending between said mounting sections for strengthening thereof and defining therewith substantially large openings through said casting which reduce the total weight thereof while maintaining the desired strength, socket means formed in said upper section for receiving tuning pins to which the ends of strings are attached and around which the strings are pulled for tensioning and tuning, and a plu rality of integral relatively narrow projections having hardened string engaging surfaces capable of resisting high local pressures exerted thereon by tensioning of the strings in contact therewith, said projections being formed from surfaces of said mounting sections over which strings are passed and being located in predetermined alignment with said socket means forming guiding, bearing, and/ or anchorage elements against which the strings may be engaged and maintained in predetermined alignment for positioning the strings forming separate notes with respect to each other and providing bearing surfaces which determine one end of the speaking length of the strings.

4. A piano plate comprising a cast metallic member having spaced apart string mounting sections, each of said sections having a string bearing portion integral with said plate, one of said mounting sections having tuning pin mounting means thereon and the other of said mounting sections having hitch pins thereon about which strings are adapted to be strung, and said hitch pins being formed integrally from said plate and having the surface portion which is harder than that of the remaining portions of said plate.

5. In a piano plate as defined in claim 4, integrally formed spacing hitch pins adapted to space two adjacent extents of a string which are adapted to form portions of different notes, said spacing hitch pins being formed as single members integral with the remainder of said plate and of greater width than the other hitch pins to provide the requisite spacing for adjacent speaking portions of a string.

6. A piano plate as defined in claim 4, in which said integrally formed hitch pins are provided with hardened string engaging surfaces extending from the associated mounting section in angular relation to the surface thereof oppositely from the direction in which the strings are adapted to be passed.

7. A piano plate comprising a cast metallic member having spaced apart string mounting sections, each of said sections having a string bearing portion integral with said plate, one of said mounting sections having tuning pin mounting means thereon and the other of said mounting sections having hitch pins thereon about which strings are adapted to be strung, and agraffes formed integrally with said one mounting section in predetermined alignment with said tuning pin mounting means, said agrafi'es having string engaging surface portions which are harder than the surface of the remainder of said plate.

References Cited by the Examiner UNITED STATES PATENTS 719,977 2/03 Ziegler 84-188 2,532,070 11/50 Moore et a1. 84-188 2,679,688 6/54 Buschman. 2,858,723 11/58 Wickham 84-188 LEO SMILOW, Primary Examiner.

CHARLES W. ROBINSON, LEYLAND M. MARTIN,

Examiners.

Claims (1)

1. A GRAY CAST IRON PIANO PLATE COMPRISING AN INTEGRAL CASTING HAVING UPPER AND LOWER STRING MOUNTING SECTIONS JOINED BY CROSS MEMBERS AND DEFINING THEREWITH A BODY ON ONE FACE OF WHICH STRINGS ARE ADAPTED TO BE MOUNTED UNDER SUBSTANTIAL TENSION, SOCKET MEANS IN SAID UPPER STRING MOUNTING SECTION FOR RECEIVING TUNING PINS TO WHICH THE ENDS OF STRINGS ARE ADAPTED TO BE ATTACHED AND AROUND WHICH THE STRINGS ARE PULLED FOR TENSIONING AND TUNING, AND PIN AND AGRAFFE MEMBERS FORMED AS INTEGRAL PROJECTIONS FROM SURFACES OF SAID MOUNTING SECTIONS OVER WHICH STRINGS ARE PASSED, SAID PIN AND AGRAFFE MEMBERS BEING CAST IN THEIR FINAL FORM AND ARRANGED AT PREDETERMINED SPACED LOCATIONS ALIGNED WITH SAID TUNING PIN SOCKET MEANS FORMING GUIDE AND/OR ANCHORAGE ELEMENTS ABOUT WHICH THE STRINGS MAY BE ENGAGED AND MAINTAINED IN PREDETERMINED ALIGNMENT UNDER SUBSTANTIAL TENSION, SAID PIN AND AGRAFFE MEMBERS HAVING SURFACE PORTIONS WHICH ARE HARDER THAN THE REMAINING SURFACE OF SAID PLATE TO RESIST IMBEDDING OF THE STRINGS THEREIN.

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