US2588440A - Piano tuning pin - Google Patents

Description

March 11, 1952 H. E. WARREN ET AL 2,588,440

PIANO TUNING PIN Filed DSC. 2, 1949 Patented Mar. 11, 1952 PIANO TUNING PIN Henry E. Warren, Lancaster, Pa., and Richard G. Warren, Bangor, Maine Application December 2, 1949, Serial No. 130,658

(Cl. Sli-205) Claims.

The present invention relates to piano tuning pins, and is concerned more particularly with improvements in tuning pins to permit a precise, screw-threaded adjustment of string tension.

The conventional tuning pin consists merely vof a short steel rod, around which one end of the string is Wrapped. The pins are mounted in closely-spaced staggered rows in the pin block of the piano, and are provided with squared ends to receive the tuning wrench. The pins are held from turning in the pin block solely by the friction between the pin and the block. As a consequence, it is essential that the pins t the pin block tightly enough to maintain the setting under the pull of the string, yet it must be possible for the tuner to rotate the pin without requiring excessive force on the wrench. Such arrangement is obviously lacking in precision oi adjustment, and increases the diiiiculty in tuning a piano. Furthermore, with the passage of time, the pin block may become worn to the extent that the pins fail to hold their setting.

In View of these diiculties, the present invention contemplates the provision of a piano tuning pin of novel and improved construction, wherein the adjustment for string tension may be made in the conventional manner, but with far greater ease and precision and with assurance that the setting will be maintained.

It is likewise an object of the invention to provide an improved piano tuning pin embodying screw-threaded adjusting means, the pin being of such construction and arrangement as will permit its use in the pin blocks of existing pianos, upon removal of the conventional pins.

A further object of the invention is to provide improved and simplified anchoring means for securing the string in the pin, so as to permit the pins readily to be installed in pianos as a replacement for the conventional pins.

The several features of the invention will appear from the following description, taken in conjunction with the accompanying drawings, in which Fig. 1 is a view in side elevation, partly broken way, of a portion of the pin block of a piano, showing our improved tuning pins mounted therein; Fig. 2 is a front View, showing the tops of the pins; Figs. 3, 4 and 5 are detail views in front, rear, and sectional elevation, respectively, of the pin; Figs. 6 and '7 are sectional details, taken on lines 6-6 and l-l', respectively, of the pin cross-section; Fig. 8 is a detail view in elevation of an alternative form of pin shank; Figs. 9 and 10 are detail views illustrating on a somewhat enlarged scale, one mode ci anchoring the string, and Figs. l1 and l2 are detail views, Fig. 11 being in section, illustrating an alternative method of anchoring the string end.

The tuning pin of the invention comprises a body I4 having an integral shank portion I6 which is adapted to be inserted in the pin block.

In existing pianos, the shank I6 will be inserted in the bores from which the conventional frictionally-held pins have previously been removed. The shank may be threaded as shown in Figs. 3, 4 and 5, or longitudinally iiuted as in Fig. 8, for ready insertion in the bores in the pin block. In the threaded form of shank, a left-hand thread is preferably although by' no means necessarily employed, for reasons that will appear.

The body portion Ill of the pin is preferably circular in cross-section, and is provided with a central bore or passage within which is received the adjusting screw I8. The screw is threaded for most of its length, and is provided at its lower end with a lug or key-like projection 20 which slides within a slot 22 formed in the body I4 of the pin. The base of the slot may conveniently be terminated in an enlargement 23, as by drilling a transverse passage to approximately the center of the pin, before milling out the slot. The engagement of the lug 20 with the slot 22 insures that the adjusting screw will not rotate within the pin during adjustment. The adjusting screw is provided with a central passage for the piano string, and the screw has at its upper end a nut 24 which bears against the top of the cylindrical body of the pin to draw the adjusting screw upwardly when the nut is tightened.

Adjacent the base of the body portion, the pin is provided with a small bore or passage 28 extending through the wall of the pin into the interior. As shown in Figs. 3 and 4, this passage is not on the center line of the pin, but slightly to one side, in order that suitable clearance may be provided between pins and strings when the pins are mounted in the pin block in the conventional staggered relation. See particularly Fig. 2. It is to prevent any tendency of the pin to loosen in the pin block, due to the offset of the line of pull of the string from the centerline of the pin, that a left hand thread is preferred for the shank I6. Where the fluted shank is einployed, the pin is oi course firmly secured against twisting.

In order that the direction of pull of the string may be changed through the approximately ninety degree angle between the direction of entry through passage 28 and the line of movement of the adjusting screw in the direction of the pin axis, a boss 30 of appreciable effective radius is provided. This boss is preferably of semi-cylindrical contour, and is disposed directly adjacent the passage 28 so that the bend may be as smooth as possible. To this end, the boss 30 is advantageously formed of round stock which is received within a transverse substantially semicylindrical recess in the body of the pin. The round stock may be secured in the recess by brazing or welding, after which the excess projecting material may be cut down to the same contour as the pin body, as shown in Fig. 7,

This construction provides the maximum cffective radius of the bend, while permitting the wire to lead smoothly into the central passage in the adjusting screw I8. Thus, even though the initial position of the adjusting screw be in fully retracted position within the pin, the pull of the string is directly along the axis of the screw, so as to minimize any tendency of the screw to bind during adjustment.

In order that thelend of the string may be anchored effectively, it is essential to avoid sharp bends and twists, not only for ease of installation but also to avoid weakening the string. Furthermore, the mode of anchoring the string end must be such as can be carried out with all p-arts of the pin in place, with the adjusting screw in retracted position and with the wire end readily accessible to the operator. Also, the securing of the string must not develop any appreciable slack in the wire, as otherwise the range of adjustment of the screw will be used up before the string h-as been brought to the-desired tension.

One manner in which the string may effective- 1y be anchored is shown in Figs. 9 and 10. After the string has been inserted and the adjusting screw slid down over the string into the body of the pin, a steel washer 36 and a thin silver alloy washer 38 are placed on the string, with the steel Washer resting on the top of the adjusting screw. The electrodes d@ of a resistance Welder (not illustrated) are then touched on opposite sides of the steel Washer, bringing the latter very rapidly to a temperature sufdcient to melt the silver washer and cause it to flow around the string. There results a silver button 42 rmly soldered to the string, yet the string, because of the indirect application of heat, need not lbe raised to a temperature which will appreciably diminish its tensile strength.

As an alternative to the silver-soldered form of anchor, the arrangement shown in Figs. l1 and 12 may be employed to hold the string securely and Without sharp bends or turns. As shown in Fig. 11, the string is brought upwardly through the central passage in the screw and outat the top, over the edge 46 that has preferably been j rounded off slightly. The wire is then passed A through a transverse passage 48, drilled slightly off-center in order that the larger size wires may preciable slack in the string after the anchoring has been completed.

It will be apparent that the tuning pin which I have described provides all the expected advantages resulting from the precise and positive screw-threaded adjustment, yet is readily adapted for use as a replacement for the conventional friction tuning pin. This results from the extremely compact construction, both in crosssectional diameter and vertical height above the pin block. As a result, the pins may be employed in the same closely-spaced arrangement as conventional pins, with no interference between pins and strings and with the adjusting nut completely accessible. See particularly Figs. 1 and 2. The provision of the oli-center entrance of the i string aids in permitting a compact arrangement of pins.

The installation of the pin is likewise greatly simplified by the open-slot construction of the vpin body, since the string end may readily be threaded through the passage 28 and out through the slot. The string, under hand-tension, is then bent up around the boss 36 and the adjusting screw slipped over the wire end and inserted into the body of the pin, after which one or the other of the previously-described anchoring arrangements is carried out to anchor the string securely. The nut 24 is then tightened until the string tension is sufficient to give the desired pitch. Because of the large eiective radius of the boss around which the string is drawn, the tension in the short length of string between boss and anchor is not substantially greater than the tension in the vibrating section.

We have found that our improved pin permits the string to be adjusted easily and precisely to the desired pitch, and that the setting will be retained over long periods of time.

Having thus described our invention, we claim:

1. A piano tuning pin comprising a body having a longitudinal bore, a shank portion having means for securing the shank within a pin block of a piano, an adjusting screw slidable in the bore, screw-threaded means for drawing the adjusting screw outwardly along the bore, means for preventing rotation of the screw in the bore, a passage through the screw axially thereof, a transverse passage in the pin body adjacentthe base of the bore, and an abutment within the bore and adjacent the transverse passage, said abutment having a surface curving from the said passage through an arc of approximately ninety degrees to substantially the center line of the passage in the adjusting screw, thereby smoothly to lead the piano string from its point oi entry to the adjusting screw.

2. A piano tuning pin comprising a body having a longitudinal bore, a shank portion having means for securing the shank within the pin block of a piano, an adjusting screw slidable in the bore, screw threaded means for drawing the screw outwardly along the bore, means for preventing rotation of the screw within the bore, a passage extending transversely of the body of the screw and into the bore adjacent the base thereof, an abutment adjacent said passage and.

around which the piano string is drawn, an axial passage in the adjusting screw to receive the string from the abutment, and a transverse passage through the adjusting screw adjacent the outer end thereof through which the string end may be passed with the free end of the string tucked through the string loop intermediate the top of the screw and the transverse passage therebelow.

3. A piano tuning pin comprising a body circular in cross-section and having a longitudinal bore therein, a shank portion for insertion in a pin block, the body of the pin being slotted for the length of the bore, an adjusting screw axially slidable in the bore, the screw having at its inner end a lug projecting outwardly into the slot to prevent rotation of the screw relative to the body, an adjusting nut carried by the screw at the outer end of the pin body, a passage axially through the screw, a passage transversely of the pin body adjacent the base of the bore substantially opposite the slot and to one side of the axis of the pin, and an arcuate abutment adjacent the passage in the pin body and extending substantially tothe center line of the pin, around `which abutment the string may pass from the transverse passage in the pin body to the axi-al passage in the adjusting screw.

4. Anchoring and adjusting means for a piano string comprising a body portion having a bore therein and a shank portion for insertion in the pin block of a piano, an adjusting screw axially slidable within the bore in the pin body, an adjusting nut carried by the screw and bearing against the outer end cf the pin body, a passage for leading the piano string transversely into the bore in the pin body, an arcuate abutment adjacent said transverse passage around which the string passes to the adjusting screw, said screw having an open axial passage through which the string leads to the top of the screw, and securing means for the string comprising a washer surrounding the string and seated on the top of the screw, and a metallic bond between the string and the washer.

5. A piano tuning pin comprising a body circular in cross-section and having a longitudinal bore therein, a shank portion for insertion in a pin block, the body of the pin being slotted for the length of the bore, an adjusting screw axially slidable in the bore, the screw having at its inner end a lug projecting outwardly into the slot to prevent rotation of the screw relative to the body, an adjusting nut carried by the screw at the outer end of the pin body, a passage axially through the screw, a passage transversely of the pin body adjacent the base of the bore substantially opposite the slot and to one side of the axis of the pin, and an arcuate abutment adjacent the passage in the pin body and extending substantially to the center line of the pin, around which abutment the string may pass from the transverse passage in the pin body to the axial passage in the adjusting screw, the shank portion of the pin being longitudinally fluted to prevent rotation of the pin body when inserted in the pin block of a piano.

6. A piano tuning pin comprising a body circular in cross-section and having a longitudinal bore therein, a shank portion for insertion in a pin block, the body of the pin being slotted for the length of the bore, an adjusting screw axially slidable in the bore, the screw having at its inner end a lug projecting outwardly into the slot to prevent rotation of the screw relative to the body, an adjusting nut carried by the screw at the outer end of the pin body, a passage axially through the screw, a passage transversely of the pin body adjacent the base of the bore substantially opposite the slot and to one side of the axis of the pin, and an arcuate abutment adjacent the passage in the pin body and extending substantially to the center line of the pin, around which abutment the string may pass from the transverse passage in the pin body to the axial passage in the adjusting screw, the shank portion of the pin being threaded in a direction which results in tightening the pin body within the pin block of a piano under the axially displaced pull of the string in the transverse passage.

7. A piano tuning pin comprising a body having a longitudinal bore therein, a shank portion for insertion in a pin block, the body of the pin being slotted for the length of the bore, an adjusting screw axially slidable in the bore, the screw having at its inner end a lug projecting outwardly into the slot to prevent rotation of the screw relative to the bodyl an adjusting nut carried by the screw at the outer end of the pin body, a passage axially through the screw, means adjacent the outer end of the screw for anchoring the string in the screw, a passage transversely of the pin body adjacent the base of the bore substantially opposite the slot and to one side of the axis of the pin, and an arcuate abutment adjacent the passage in the pin body and extending substantially to the center line of the pin, around which abutment the string may pass from the transverse passage in the pin body to the axial passage in the adjusting screw.

8. A piano tuning pin comprising a body having a longitudinal bore thereiny a shank portion for insertion in a pin block, the body of the pin being slotted for the length of the bore, an adjusting screw axially slidable in the bore, the

' screw having at its inner end a lug projecting outwardly into the slot to prevent rotation of the screw relative to the body, an adjusting nut carried by the screw at the outer end of the pin body, a passage axially through the screw, a transverse passage through 'the adjusting screw adjacent the outer end thereof for anchoring the string in the screw, a passage transversely of the pin body adjacent the base of the bore substantially opposite the slot and to one side of the axis of the pin, and an arcuate abutmentl adjacent the passage in the pin body and extending substantially to the center line of the pin, around which abutment the string may pass from the transverse passage in the pin body to the axial passage in the adjusting screw.

9. A piano tuning pin comprising a body having a longitudinal bore therein, a shank portion for insertion in a pin block, the body of the pin being slotted for the length of the bore, an adjusting screw axially slidable in the bore, the screw having at its inner end a lug projecting into the slot to prevent rotation of the screw relative to the body, an adjusting nut carried by the screw at the outer end of the pin body, a passage axially through the screw, means for securing the string at the top of the screw, a passage transversely of the pin body adjacent the base of the bore, said passage being directed to one side of the axis of the pin and aligned with the open slot in the pin body, and an arcuate abutment within the bore and around which the string is drawn to the adjusting screw in a curve substantially tangential to the transverse passage in the body of the pin.

l0. A piano tuning pin comprising a body having a longitudinal bore therein, a shank portion for insertion in a pin block, the body of the pin being slotted for the length of the bore, an adjusting screw axially slidable in the bore, the screw having at its inner end a lug projecting into the slot to prevent rotation of the screw relative to the body, an adjusting nut carried by the screw at the outer end of the pin body, a passage axially through the screw, means for securing the string at the top of the screw, a passage transversely of the pin body adjacent the base of the bore, said passage being directed to one side of the axis of the pin and aligned with the open slot in the pin body, and an abutment substantially semi-circular in cross-section secured in a transverse recess in the pin body above the transverse passage therethrough, around which abutment the string is drawn through approximately ninety degrees from said passage to the adjusting screw.

HENRY E. WARREN. RICHARD G. WARREN.

No references cited.

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