US449409A - Piano-tuning apparatus - Google Patents

Description

(No Model.)

A. PELLDIN.

PIANO. TUNING APPARATUS. No. 449,409. Patented Mar. 31,1891.

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ABRAHAM FELLDIN, OF AUBURN, l l llV YORK.

PIANO-TUNING APPARATUS.

SPECIFICATION forming part of Letters Patent No. 449,409, dated March 31, 1891.

Application filed March 28, 1890- Serial No. 345,768. (No model.)

T0 all who/)0 it 71mg concern:

Be it known that l, ABRAHAM FELLDIN, a citizen of the United States, and a resident of Auburn, in the county of Cayuga and State of New York, have invented new and useful Improvements in Piano-Tuning Apparatus, of which the following is a specification.

The object of my invention is to provide a simpler and more efficient tuning or stretching pin device for pianos and other stringed instruments than such as are now in use; and it consists of a metallic pin having a plain lower section fitted to a plain hole in the meia-llie frame or bar used for holding the pins; and it also consists in the improved auxiliary adjusting device for effecting finer adjustment of the strings than may be readily accomplished by the pins alone, all as hereinafter fully described, reference being made to the accompanying drawings, in which- Figure 1 is a plan view of a section of a stretching-frame and some strings adjusted with my improved apparatus. Fig. 2 is a longitudinal sectional elevation of the same. Fig. 3 is a sectional elevation of part of the same, showing a modified arrangement of the tuning or stretching pins. Fig. 4; is a plan of the auxiliary tuning device inverted. Fig. 5 is a side elevation of one of the tuning or stretching pins on an enlarged scale. Fig. 6 is a detail of Fig. 2 on an enlarged scale, illustrating the invention more fully.

A represents part of the metallic frame or plate for supporting the tuning or stretchingpins 1). It is bored at c for the pins, somewhat larger than the usual dimensions and preferably at the slight inclination usual for giving the pins a slight pitch in the direction opposite to the pull of the strings (I; but they may be in a perpendicular angle thereto, and they may be bored either partly through the plate, as in Fig. 2, or entirely through it, as in Fig. 3. The pins 1) are made with the lower plain section preferably slightly larger than the rest, and when the holes are not bored through the plate preferably a little shorter than the depth of the holes; but they may in this case be longer, and they should be longer when said holes are bored through, as in Fig. 3. The plain section is made sensibly smaller than the hole, and after being so made and otherwise fitted, as required, the pins are placed in their respective holes, and with a brace wrench applied to the upper end of each one separately and strongly pressed in the direction of the pull of the strings the pins are turned a few times by the brace, and thereby ground off at the angles 0, Figs. 2 and 5, or

grooved between the angles, as at f, Fig. 3, according as said angles or the plain surfaces between the angles are made to bear against the walls of the holes at g.

In the arrangement of Figs. 2 and 5 the angles of the lower plain parts of the pins also produce slight grooves in the walls of the holes, as more clearly seen in Fig. (5, and although the edges of the holes are slightly worn away in producing the grooves of Fig. 3 they engage the grooves of the pins, and in like manner the slightly-rounded angles of the arrangement in Figs. 2 and 5 engage the slight grooves they produce in the walls of the holes, and both alike constitute when subject to the stress of the strings an interlocking device, effectually preventing any tendency of the pins to rise and escape from the holes, such as plain pins would have in plain holes, through the influence'of the vibrations of the strings and supporting-frame and any shocks and jars, such as they are subject to in the handling of the instruments. At the same time the bearing-points thus produced have such limited area of surface-eontact that they have a slight abrading or biting effect, producing more friction under the stress of the strings, and therefore hold more effectually against the tendency of the strings to pull them slack than pins of a like character having largerbearingsurface. For the same reason and because it is preferred to make these pins somewhat larger than such pins are usually made, which also adds to their resistanceagainst being turned, it is desirable to provide a means of more sensitive adjustment than may be had with them alone without too much care. I therefore provide the tension-bar li, extending along over the strings (Z between the agraffe '2 and the bridge so as to touch or bear to some extent on the strings when stretched by the pins Z), and having a bored hole directly over each string, with a sliding pin 7; and ad justing-screw Z in each hole, the sliding pin having a slit in the lower end resting on the string to insure the alignment of the string across the end of the pin, and the screw extending above the bar and fitted for the ap plication of a key or socket wrench for turning it. These screws are fitted'so as to turn freely in the holes of the bar, and, having only the friction due to the thrust of the sliding pins on the ends, turn very freely and admit of being turned with a small light key and so as to effect much finer adjustment than can be well done with the pins b.

The bar It is attached to the base-plate A by stud-screws m at suitable intervals adapted to hold it against the stress of the strings and at asuitable height above the base.

I am aware that such an auxiliary tensionbar, adj ustin g-screws, and pins have been employed in an arrangement in which the strings are threaded in slots of the bar and through eyes of the pins above the lower surface of the bar, and I do not claim these devices, broadly, myinvention being a contrivance for greater simplicity in the construction and in adjusting the strings and for economy in the cost of making;

In my patent No. 343,805 holes for the pins are shown which are in part reamed or drilled larger than the rest of the holes, and I do not in this case claim such arrangement, it being an especial feature of the present invention that the holes for the pins are of uniform size throughout and just as produced by the drill.

I am also aware that in a bar located over the strings adjusting-screws have been made to extend through the bar and bear on the I strings, but not having the bearing-pins, without which the strings are liable to escape from the screws, which have to turn on the strings.

I claim 1. In a string stretching or tuning device, the combination, with the metallic supporting bar or frame having a plain bored hole for each pin, of a pin for each hole of uniform size throughout its length having a plain section inserted in the hole having bearings at the points therein where it hasv contact by the pull of the strings,substantially as described.

2. In a string stretching or tuning. device, the combination, with the metallic supporting bar or frame having a plain bored hole of uniform size throughout its length for each pin, of a pin for each hole having a plain section of the lower end shorter than'the depth of the hole and larger than the portion of the pin directly above it and having bearings at the angles of the larger section where it has contact by the pull of the strings, substantially as described.

3. The combination, with the strings, of

the auxiliary tension-bar placed over the strings and bored through for the pins and adjusting-screws, the loose pins in said holes and projecting from the lower side of thebar and bearing on the strings, and the adjusting-screws in said-holes above the pins, substantially as described.

In testimony that I claim the foregoing as my invent-ion I have signed myname, in presence of two witnesses, this 13th day of March,

r ABRAHAM FELLDIN. Witnesses:

A. C. ELLISON, J. RosEoRANs.

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