US3461768A - Piano plates - Google Patents

Description

C. ULTES, JR

Aug. 19., 1969 PIANO PLATES Filed June 10, l

FIG-1 3 9 3.

INVENTOR CARL ULTES,JR.

7 w, M gs ATTORNEYS United States Patent O 3,461,768 PIANO PLATES Carl Ultes, .lr., Springfield, Ohio, assignor to The 0. S. Kelly Company, Springfield, Ohio, a corporation of Ohio Continuation-impart of application Ser. No. 531,512, Mar. 3, 1966. This application June 10, 1968, Ser.

Int. Cl. Gc 3/08' US. Cl. 84188 3 Claims ABSTRACT OF THE DISCLOSURE A cast iron piano plate incorporates hitch pins or agratfes which can locate the string precisely with respect to the surface of the plate and surrounding parts. The pins or agraffes are formed from a material substantially more ductile than the cast iron and are driven into formed holes in the plate, the root section of the pin is knurled or serrated and is deformed as the pin is driven, thereby obtaining a tight fit, regardless of differences in hole diameters or out of round conditions of the hole, with risk of cracking the plate. The section of the pin protruding from the plate may also be serrated or knurled, .and can deform under pressure from the strings, thereby serving to locate the string on the pin and at any desired elevation with respect to the plate.

CROSS REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of copending application Ser. No. 531,512 filed Mar. 3, 1966 (now abandoned) for Piano Plates, and assigned to the same assignee as this application.

BACKGROUND OF THE INVENTION This invention relates to piano plates, particularly to improved piano plate constructions incorporating novel hitch pins, guide pins, and/or agraife pins.

One requirement of a piano plate is that of high vibration dampening capacities, so that the plates will not vibrate in resonance with the strings. Plates have been made of various metals but gray cast iron has the high dampening capacity while providing also the necessary strength for supporting the high loads exerted on the plate due to tensioning of the strings.

The strings are placed across one surface of the plate, which may receive tuning pins in a predetermined section thereof. The ends of the strings are suitably fastened to the tuning pins, and may pass around or through agraffe pins 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 at the top and bottom (or front and back in the case of grand plates) and ends of the strings, opposite the tuning pins, pass around or are secured to hitch pins which provide a fixed anchorage therefor.

It is customary to provide agraife pins, guide pins and hitch pins as separate individual pins, usually of steel, which are driven into individual holes formed in the plate. Some of these pins may be bent to predetermined angles in accordance with their desired function, or some of the holes may be drilled at a desired angle. It will be appreciated that the drilling of all the holes in the plate to re- "ice ceive agraffe and hitch pins, together with the fitting, placing and proper bending of pins, represents considerable time and cost in the manufacture of piano plates.

In order to assure properly sized holes for receiving the hitch pins, agraffes or other pins, the usual practice is to drill the holes to spots or dimples, and at times using a jig to locate the many holes for those steel pins. Both the jigs and the drills will wear and contribute to possible slight malformation of the holes, requiring that various sizes of pins be fitted. This involves further time and expense, and requires an inventory of a number of different size pins.

The assembler chooses the pin of the proper diameter to obtain the tight press fit in the holes in the plate. In fact he may find it necessary to use several ditferent sizes of pins in one plate, and in the course of this fitting he may destroy one or more pins.

This present system creates some difficulty in stocking and handling the materials, particularly since the pins may dilfer in diameter by a very small amount, not visible to the naked eye.

As to locating the strings above the plate surface, presently used pins are smooth and do not offer any chance for the string to locate along the protruding section of the pin before full tension is applied. The usual present practice is to bend the pin away from the run of the string, such that the string rides down into contact with the plate.

SUMMARY OF THE INVENTION The present invention provides novel piano plates wherein hitch pins or agrafies are firmly anchored to the plate and may include a head or protruding section formed to locate the string with respect to the surrounding areas of the plate and other parts. The invention also provides novel hitch pin and agraffe constructions which may be driven into previously formed holes in the plate and firmly anchored therein, regardless of slight differences in the size or shape of the holes. These pins incorporate a root section having portions provided with outwardly formed segments which are of a predetermined maximum diameter, and which are separated by other segments of a predetermined minimum diameter, and wherein the material from which the pin is formed is a metal substan tially softer or more ductile than the gray cast iron from which the pin is fabricated, whereby the greater diameter segments can deform into at least some of the maximum diameter segments to produce a tight fit of the pin in its hole in the plate regardless of differences in the size and shape of that particular hole from the nominal size thereof. Also, these pins may be provided with such structures at either end, whereby either end of the pin may be driven into a hole in the plate, and the opposite end provides a head section which may deform slightly under pressure from the string when the plate is strung and the strings are drawn to the proper tension, thereby assisting in locating the strings firmly in predetermined position with respect to the surrounding plate.

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

In the drawings FIG. 1 is a general view of a typical piano plate to which the present invention applies;

FIG. 2 is an enlarged sectional view showing a novel hitch pin placed in the plate according to the invention;

FIG. 3 is an enlarged view similar to FIG. 2, showing the pin and a portion of a related string;

FIGS. 4 through 7 are perspective views showing various forms of pins provided by the invention; and

FIG. 8 is an enlarged detail sectional view showing the manner in which a pin as in FIGS. 2 and 3 is drive fitted into a hole in the piano plate.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring to the drawings, FIG. 1 is an overall view of a so-called overstrung plate for an upright type of piano. It should be understood that this particular type of plate is described merely for purposes of explanation. 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, a relatively hard and brittle material, 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.

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 which receive tuning pins 27 mounted in suitable bushings (not shown) and about which ends of the wire strings are engaged and wrapped.

The strings 20 extend from one tuning pin downwardly to or around hitch pin members indicated generally at 30, on the lower section 12, and in some cases back again to another tuning pin. In passing from the tuning pins the strings engage over a bearing surface or bead 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 may pass over and in engagement with a bearing surface which may (if used) 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 (some of which are usually wrapped), 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 the tuning pins are generally offset somewhat from the path along which the strings extend, particularly in the base section, and in passing over the bearing surfaces, indicated by the general reference numeral 35, these strings are engaged around agraffe pins 38 which serve to position the strings in proper alignment and redirect them over the bearing surface toward the lower mounting section 14.

As previously mentioned, the holes 40 (FIG. 2) for the hitch pins or agraffe pins are usually drilled to spots or dimples in the cast iron plate, sometimes using a suitable jig to position the drill bits. As the drill bits become dull or chipped or for other reasons such as jig wear, the holes 40 may no longer be in truly circular cross-section. They may become distorted, out-of-round, or made oversized due to the drill bits runningolf center. In a typical application, a #24 drill is used, which when sharp and run true will produce a hole of 0.153 to 0.154 inch. In this hole a mild steel pin having a diameter of 0.157 inch is driven. In order to allow for the various malformed holes, due to the causes previously mentioned, several sizes of pins are used, with the minimum size having a diameter of 0.157 inch and the maximum having a diameter of 0.187 inch.

To attain a tight drive fit using only one size pin, the present invention provides novel hitch pins and agratfe pins which have an end or root section thereof, intended to be driven into the hole, formed with an irregular surface which has some segments at a maximum diameter, and intermediate segments at a minimum diameter. The pins are manufactured from a relatively mild steel which is sufficiently ductile that it will deform when driven into 'a hole in the cast iron. This is a necessary factor, since it must be the pin that deforms, otherwise the relatively hard and brittle casting may be cracked and damaged to such an extent that the entire plate would be useless.

In FIG. 4, a novel hitch pin 50 is shown having end portions 52 adapted to be driven into one of the holes 40. In this form the section 52 is formed by fluting, so that there are a number of ridges which extend beyond the initial diameter dimension of the pin 50, while in between these ridges there are depressions which have a minimum diameter less than the original. In one typical embodiment, the diameter of the stock from which the pin 50 is manufactured is 0.156 inch, and the maximum diameter of the outwardly extending ridges of the fluted section 52 is about 0.167 inch, with the depressions between these ridges being slightly less than 0.156 inch in diameter. The protruding section of the pin thus includes a part of somewhat greater diameter than the partially exposed center 53 of the pin. Similar pins have been used with the entire pin provided with a fluted configuration.

There are several advantages and uses of this type pin. First, the double-ended pin eliminates the need to be selective; either end can be driven into a hole. Second, the fluted part of the protruding section presents ridges or portions that are somewhat thin and deformable under pressure from the tensioned wire strings. The strings can embed in the pin surface, and thus be located at a desired elevation with respect to the surrounding plate. Third, as an alternative arrangement, the string can be located around the exposed part of the center section, and the string will be prevented from riding up the pin.

These features minimize or eliminate the need to bend the pins or to insert them at an angle, as has previously been necessary, and this simplifies the construction of the assembled plate and pins.

FIG. 5 shows another embodiment of the invention wherein the pin 50a has end sections 52a knurled to provide a number of outwardly extending diamond shaped parts that protrude to the maximum diameter, while the segments in between these parts are of the minimum diameter. This configuration is particularly good where it is desired to locate the string on the exposed section 52a. The rough surface aids in holding the string which is being placed .and brought to proper tension.

FIG. 7 shows another configuration in which the main portion 50b of the pin has a deformed end 52b which is deformed in a spiral configuration, such that the outer edges of the spiral are formed out to the maximum diameter, while the valleys or depressions in between are at the minimum diameter.

FIG. 6 shows a further embodiment in which the head 500 is also provided with upper and lower shoulders 54 and '55. Below the shoulder 55 the pin is deformed in a number of annular rings 52c, again with the outer diameter of these rings being at the maximum desired diameter, and the areas in between being at the minimum diameter. In this case, the shoulder 55 can provide a seat or limit which will engage the surface of the plate around the hole and serve as a guide to the depth to which the pin is driven, as well as covering any burrs that may form. The upper shoulder 54 serves as the stop to prevent the string from riding up off the end of the pin. Such an arrangement also facilitates the use of machines for driving the pins into the plate. Similarly, the shoulder 55 in this case will automatically limit the depth to which the pin can be driven so that the adjustment of a machine for driving the pins is simplified. Obviously, the shoulders can also be provided if desired on the other configurations of the pm.

As shown particularly in FIG. 8 the diameter of the hole in the plate is indicated at 55, and the initial maximum diameter of the pin 50 is indicated at 56. When the pin is driven, some of the segments of the fluted end will be forced into the depressed segments therebletween. Since the metal of the pin is sufficiently ductile, the material will flow in this manner to form a tight drive fit between the pin and the hole in the plate. The amount of deformation of the pin will depend upon the actual size and degree of deformation of the hole, but in any event there is sufiicient latitude provided that in all cases the pins will be firmly seated in the holes, without the need to select many different sizes of pins.

From the foregoing it will be seen that the pins provided by the invention are unique particularly with respect to the surface configuration formed on the pin which ultimately becomes the root section driven into a hole in the plate. Where the same configuration is employed throughout the length of the pin, placing the string against this surface configuration on the protruding section of the pin can result in the string, once it is brought to the proper tension, being partially embedded in this protruding section of the pin, and thus forming an anchor point which keeps the string from riding up or down the pin. In some instances this may be sufficient to properly locate or anchor the string without need for bending the pin further, although the pin can be bent similar to plain prior art pins, for example as shown in FIG. 2. In those configurations, where the pins are provided with some uneven surface configuration at both ends, and the metal of the pin remains smoother at the center, this same arrangement, where the string embeds in the irregular surface of the protruding part, can be employed, or the string can engage immediately beneath this irregular end configuration on the protruding section, and since it is of somewhat larger diameter than the central section of the pin, this also can prevent the string from riding up off the pin.

It should be understood that the invention is not limited to the precise forms of pins shown, and many different types of irregular surfaces may be formed on the pins to produce the desired result. Likewise, the pins do not necessarily have to be formed from round stock, but may be oval, octagonal, or other suitable shapes in cross-section.

While the form of apparatus herein described constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form of apparatus, and that changes may be made therein without departing from the scope of the invention.

What is claimed is:

1. In a piano plate formed from a relatively hard and brittle material such as gray cast iron, said plate having formed therein a plurality of holes of predetermined dimension and in a predetermined pattern to provide sockets for hitch pins, agraffe pins, and the like, wherein said holes may vary in diameter and/ or in concentricity up to several hundredths of an inch, pins mounted in and protruding from said holes and formed of a relatively ductile and substantially less hard material than said plate as, for example, from a mild steel; the improvement comprising said pins having a root section thereof inserted in a hole and formed with an irregular surface which has an outer diameter initially slightly greater than the largest diameter of said holes and an inner diameter at its depressions which is less than the smallest diameter of said holes, said pins having their said root sections driven into the holes and at least some portions of the irregular surface of said pins being permanently deformed by forced contact with the relatively harder material defining the holes in said plates into regions between the wall of the holes and the portions of the pins of lesser diameter whereby the deformed metal of the pin is compacted and distributed within the hole to provide a firm anchorage for said pins regardless of variation in diameter among the holes, said pins having a central section adjoining said root section and protruding from said plate, and said pins having an end part on the central section and located exteriorly of said plate, said end part being formed with an irregular surface corresponding to said root section prior to deformation thereof whereby the end part provides an exposed larger diameter section for engagement with a string.

2. In the art of manufacture of piano plates wherein a plate is formed of gray cast iron material having .a relatively great hardness and being relatively brittle, and wherein said plate is formed with a plurality of holes of nominal diameter in predetermined locations, said holes varying in size and/or shape due to inaccuracies in the operation by which the holes are formed; the improvement comprising pins adapted to be drive fitted into said holes with a substantial section of the pin protruding from the plate and formed of a material such as a mild steel which is ductile and has substantially less hardness than the gray iron from which said plate is formed, the root section of said pins intended to be driven into said holes having an irregular surface formed by a plurality of depressed segments therein with the metal between the segments being formed outward from the initial diameter of the pin to a diameter somewhat greater than the nominal diameter of said holes and the diameter between diametrically opposite ones of said segments being slightly smaller than the nominal diameter of the holes, said outwardly formed metal of the pins being adapted for permanent deformation into the segments therebetween during drive fitting of said pins into holes in the plate to provide a rigid drive fit connection of each pin into its respective hole, means providing a shoulder on said pins spaced from said one end thereof and arranged to be located spaced above the surface of the plate surrounding the holes into which the pins are driven, said means providing a shoulder being a corresponding irregular surface formed by a plurality of depressed segments formed on the other ends of the pins, whereby either end of the pins may be driven into a hole in the plate and the other projecting end forms the shoulder.

3. In the art of manufacture of piano plates wherein a plate is formed of gray cast iron material having a relatively great hardness and being relatively brittle, and wherein said plate is formed with a plurality of holes of nominal diameter in predetermined locations, said holes varying in size and/or shape due to inaccuracies in the operation by which the holes are formed; the improvement comprising pins adapted to be drive fitted into said holes with a substantial section of the pin protruding from the plate and formed of a material such as a mild steel which is ductile and has substantially less hardness than the gray iron from which said plate is formed, the root section of said pins intended to be driven into said holes having an irregular surface formed by a plurality of depressed segments therein with the metal between the segments being formed outward from the initial diameter of the pin to a diameter somewhat greater than the nominal diameter of said holes and the diameter between diametrically opposite ones of said segments being slightly smaller than the nominal diameter of the holes, said outwardly formed metal of the pins being adapted for permanent deformation into the seg- 7 ments therebetween during drive fitting of said pins into holes in the plate to provide .a rigid drive fit connection of each pin into its respective hole, means providing a shoulder on said pins spaced from said one end thereof and arranged to be located spaced above the surface of 5 the plate surrounding the holes into which the pins are driven, said means providing a shoulder is a head on the other end of the pins, and said head also including a lower shoulder adapted to seat against the surface of the plate surrounding the holes.

8 References Cited UNITED STATES PATENTS 1,989,018 1/1935 Norwood 855 3,204,508 9/1965 Ultes 84--188 RICHARD B. WILKINSON, Primary Examiner EDITH C. SIMMONS, Assistant Examiner US. Cl. X.R.

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