US172244A - Improvement in piano-fortes - Google Patents

Description

2 Sheets-Sheet 1.

s. P. BROOKS.

PIANO-FORTE.

Patented Jan.18,1876.

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PIANO-FORTE. No.172,244. Patented Jan. 18, 1876.

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srnrnnn'r. BROOKS, or BOSTON, MASSACHUSETTS.

IMPROVEMENT IN PIANO- FORTES.

Specification forming part of Letters Patent No. 172,244, dated January 18, 1876; application filed May 25, 1875. Y i

To all whom it may concern: Be it known that I, STEPHEN RBRooKs, of Boston, in the county of Suffolk and State of Massachusetts, have invented certain Improvements in Piano-Fortes, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, making part of this specification, in which a Figure 1 is a perspective view of a section of a piano-forte'with my improvements applied thereto, the hammer being represented in the position it occupies before the key is depressed. Fig. 2 is a vertical section through the same, representing; the position of the parts imme diately after theham mer has struck the strings. My present invention consists in arranging at different angles two sets of stringsone tuned an octave above the other, the plane of one set crossing the plane of the other set at the striking-point, so as to admit of all the strings being sounded simultaneously by the same hammer, which construction enables me to place the strings at a sufficient distance apart to prevent them from interfering with each other, and thus successfully employ two sets of strings for each note, a desideratum heretofore unattained.

My invention also consists in providing each set of strings with a separate and independent bridge or rest, placed at such distance from the strikingpoint as to give the required tone.

My invention also consists in the arrangement of the tuning-screws of the two sets of strings upon opposite sides of the string-plate, in order to economize space.

To enable others skilled in the art to under-- stand and use my invention I will proceed to describe the manner in which I have carried it out. i

In the said drawings, A represents a portion of the key-frame, towhich the key-lever B is pivoted at a in a well-known manner. From a point near the inner end of the lever B rises a post, 0, having its top inclined slightly down toward the front of the lever. Upon the upper surface of the key-lever, and at a short distance from the post 0, is secured a block, D, between ears I), at, the outer end of which is pivoted the lower end of the flystem at of the hammer H, the butt G being pivoted between the bifurcations e of a piece,

I, secured to the upper surface of the rail J.

K is the string-frame, provided with two parallel bridges. h 2', near its top, and two parallel bridges, is Z, near its bottom, over which are drawn two sets of strings, or a, there being two strings in each 'set. The pair of strings m are longer than the pair a, and are secured at their lower ends around a pin, 1?, and are tightened at their upper ends by means of tuning-screws r, at the back of the string-frame, the strings 112 being drawn over and resting upon the front of their upper and lower bridges h k. The bottom of the strings a pass down through the bridge 70, and are similarly secured around another pin, 8, and tightened at their tops by a pair of tuningscrews, t, in front of the string-frame; but these strings n are drawn over and rest on the back of their upper bridge t, and on the front of their lower bridge 1, by which construction suficient room is afforded to place and operate two sets of tuning-screws. an are guidepins, by which the two pairs of strings m a are secured to the sound-board L, and kept at the proper distance apart, the arrangement of the bridges being such that the strings do not at any point in their entire length lie in a common plane, excepting at their striking-points, where the plane of one set intersects that of the other, at which'point all four of the strings lie in one and the same plane, so that all are in a position to be struck simultaneously by the same hammer.

It will be seen that in order to tune two sets of strings so that one set will be an octave above the other, as is required to produce the proper tone, it is necessary to have the strings of the lower octave longer than those of the upper octave, and as each string must be struck by the hammer at a distance of about one-eighth of its length from its point of support, and as the striking-points of the strings of both sets must be in line so as to be struck simultaneously by the hammer, it is absolutely necessary to employ two separate and independent bridges,.h t, at one end, (one for each set of strings,) placed at diflerent distances from the 1 common striking-point, as above described,

and by this construction I am enabled successfully to employ two sets of strings for each note, without any liability of their interfering with each other when vibrated, and thereby greatly improve and perfect'the tone of the instrument.

When the front of the key-lever B is de-. pressed the top of the fly-lifter acts upon the notched portion or escapement of the butt in such manner as to swing the hammer on its pivot, and cause its point to advance toward and strike the four strings at the same time, as desired, the lower end of the butt, with its cushion 11, being simultaneously brought against a cushion or stop, w, on the end of an adjustable screw, 00. Immediately after the hammer strikes the four strings it is relieved by means of its escapement c from contact therewith, and recedes a slight distance therefrom, where it is held firmly by the post 0,

which has been raised so as to bring its inclined top into contact with the cushion c on the under side of the butt, the post 0 serving as a back catch to keep the hammer in close proximity to the wires, (see Fig. 2,) so that a note may be rapidly repeated, at the will of the player, by a very slight motion of the keylever.

What I claim as my invention, and desir to secure by Letters Patent, is- 1. In combination with the two sets of strings m n, arranged in different planes, the bridges h 'i and is Z, substantially as described, for the purpose set forth.

2. In combination with two sets of strings, on n, and the bridges h t and 70 l, the hammer H, arranged to operate substantially as described.

Witness my hand this 20th day of May, A. D. 1875.

STEPHEN P. BROOKS.

Witnesses:

N. W. STEARNS, W. J. CAMBRIDGE.

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