US503167A - Agraffe - Google Patents

Description

(No Model.) 2 Sheets-Sheet 1. F. SCHIMMEL & S. F. NELSON.

AGRAPFB.

.P'atentd Aug. 15, 1893.

m l. [Ul/l @ummm Y (No Model.) 2 Sheets-Sheet 2.

F, SGHIMMEL & S. P. NELSON. AGRAPFE.

No. 503,167. Patented Aug. 15, 1893.

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FRIDOLIN SCHIMMEL AND SEARICK F. NELSON, OF MINNEAPOLIS, MINNESOTA.

AG RAFFE.

SPECIFICATION forming part of Letters Patent No. 503,16*?, dated August 15, 1893.

Application filed September 27, 1892. Seria1N0.447,018. (No model.)

To @ZZ whom t may concern:

Be it known that we, FEIDOLIN SCHIMMEL and SEAEICK F. NELSON, of the city of Minneapolis, county of Hennepin, State of Minnesota, have invented a certain new and Imfproved Agraife, of which the following is a specification.

Our invention relates to pianos and in particular toa new and reliable means for exerting an even and adequate tension upon each string of a piano.

The object of the invention is to replace the old style agraffe or tension bar by one of greater simplicity and cheapness, and which by its peculiar construction and attachment will give to a piano an evenness and softness of tone unattainable where bars of the ordinary type are employed; and a further object which we have in view is to provide a perfect scale from one end of the key-board to the other, without the inaccuracy of pitch which exits in the pianos of the present day. This we accomplish as shown in an actual piano of our construction.

Our invention consistsin general in the constructions and combinations hereinafter described and particularly pointed out in the claims, and will be more readily understood by reference to the accompanying drawings, in which Figure l is a front view of a piano string board or frame of the construction embodying our invention. Fig. 2 is a sectional view thereof on the line :nof Fig. l. Fig. 3 is an enlarged vertical section on line a--e of Fig. l. Fig. 4: shows the agraffe or pressure bar solid with the iron frame. Fig. 5 shows a modified form of our invention.

In the drawings, 2 represents the iron frame of the piano placed over the wooden back frame 3, having the pin block portion a in which are the pins 5, arranged in the usual manner so that the strings are` formed in groups of three. For clearness a great many of the strings are left out in the drawings. The lower edge or shoulder of the pin-block opening 6 in the iron frame is provided with the seat projections or parts 7, preferably three in number and equal-distances apart, like seats being formed at the end of the open ing to receive the ends of the agraffe bar 8,

which is provided with the holes for thelarge screws 9, passing through the iron frame into the wooden frame of the piano. The bar has a general inclination downwardly so as to cross the strings at as nearly right angles as possible, and has the long ogee curved form shown accurately in Fig. 1. The lower corner of the bar is scalloped out giving the bar the cross section and strength of an angle bar without unnecessary weight. The back of the bar has surfaced seats to engage the surface projections on the plate, which are broad and aiford a solid bearing therefor. On the rear side of the bar and preferably ranging along the upper edge thereof is the narrow bead or edge l0, having a comparatively sharp edge to bear against the strings ll. Beneath this rim the bar is out back to remove it from contact with the strings extending beneath the same and over the sharp bridge l2 formed integrally with the iron frame. This bridge instead of being carried along parallel with the agraffe bar departs therefrom gradually, beginning at the upper end where the longest strings engage it, so that at the lower right hand end the bridge stands a considerable distance away from the agraffe bar leaving a much longer length of string between the pins and the bridge. By this regular lengthening of the distances between the bridge and the agraffe bar it will be seen thata regularpress ure equal at all points is obtained by the bar. The purchase of the agraife bar upon the strings becoming' greater as a string grows shorter, until at the last short group of strings, the distance between the pins and the bridge is so great that the movement of the bar against the same in this secured position is very slight, the requisite tensionIupon the strings being obtained without putting the same at too great an angle of strain beneath the sharp rear edge of the agraffe bar. In

consequence of this construction the life of the strings is len gthened, a greater latitude of adjustment secured for obtaining the proper pitch or tone of each string. From this easy IOO of the cross section shown in Fig. 5,in which the sharp edge 15 corresponding to the rib 10 of Fig 3, is arranged about midway on the back of the bar, being equally sharp with the other and about in line with the screws. We prefer the first construction, however, as we find in placing the bar upon the strings that the lower corner 16 of the agraffe bar (Fig. 3), strikes the seats upon the plate in advance of the upper edge, so that the rib 10 is brought down through a short arc of a circle; admit-` ting of a finer adjustment than can be obtained with the bar shown in Fig. 5. Both of these bars are of very large cross section as compared to any of the devices before employed and combine the qualities of perfect solidity and inflexibility, with that of neatness.

In some cases where it is desired to still further rednce the cost of construction, we cast the agraffe bar 18 Fig. 4 integral with the plate or frame, finishing only the sharp rib on the back of the bar and edge of the bridge 12. One of the great advantages of either of our constructions is that we are enabled to exert an even tension without the employment of the great number of screws now found in pianos, which of themselves rattling in their places do much toward producing the harsh metallic sound, which we in our pianos fully avoid.

Having thus described our invention, we claim as new and desire to secure by Letters Patent- 1. The combination, with the metal piano frame or board, of the pins and strings, agraffe bar arranged on said frame, and a bridge arranged angularly with respect to said agraife bar, being farthest away therefrom at the point where the shortened strings cross the same, substantially as and for the purpose specified.

2. The combination, with the piano frame, of the single cast metal agraffe bar, provided with the continuous rib on its under side, the strings, and the bridge 12 departing from said bar as described,and both beingcurvedfsubstantially as and for the purpose specified.

3. The combination with the metal piano frame and the pin block, of abridge, the pins, the strings extending therefrom over said bridge, the seats 7 arranged upon said metal frame and an agraife consisting of a single infiexible metal bar, having a broad and substantially fiat back provided with an integral sharp rib 10 to engage the strings, and said bar having the shoulders or projections 16 to rest upon said seats and five screws extending therethrough into the seat portions substantially as and for the purpose specified.

In testimony whereof I have hereunto set my hand this 17th day of September, 1892.

FRIDOLIN SCHIMMEL.

In presence of H. M. LAUBENHEINER, E. C. HAMBURGHER. In testimony whereof l have hereunto set my hand this 13th day of September, 1892.

SEARICK F. NELSON. In presence of- O. G. HAWLEY, F. S. LYON.

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