US2614449A

US2614449A - String instrument

Info

Publication number: US2614449A
Authority: US
Publication date: 1952-10-21
Anticipated expiration: 1969-10-21

Description

Oct. 1952 F. MACHALEK STRING INSTRUMENT I Filed April 12, 1949 Patented Oct. 21, 1952 UNITED STATES PATENT OFFICE Application April 12, 1949, Serial No. 87,045 Iniczechosloyakia April 12, 19 48:

61' Claims. 1

Stringed musical instruments are generally providedwith a. set of individual strings, which are :tuned to azcertain frequency andactuated in any known :way either. to produce sounds which are directly audible or to vibrate mechanically in a frequency range corresponding.v to inaudible sounds, in which case such vibrations are picked up electrically, electrostatically or electromagnetically andreproduced by means of. an. amplifier supplying a loud speaken.

Instruments of such a kind must be. rather frequently. tunedto keep their oscillating frequencies. on/the. desired value. especially if the strings'are. of different material and thickness and iftheyare subject to changes of temperature or moisture content inthesurrounding air.

Itis an object ofthe. invention to provide such an. instrument, where thetuningof the strings maybe either completely eliminated or at least reduced to ameasure, where the wholetuning may be carried out quickly andv more accurately.

In..accordance...with. known physical laws, the oscillating frequency ofa string is directly proportional tov the square. root of its tension and indirectly, proportional. to the length of. the string and to the squareroot of its mass. If a single stringis used, thediiferent partsof which are used for generatingdifierent frequencies, and an equal. tension of the different string parts is kept, themass. remains equal and. the resulting frequency is only. indirectly proportional. to the length of the respectivestringpart.

The invention isby. way. of example shown diagrammatically, in the accompanying drawing, showing. in Fig. lone suitable. arrangement, in Fig. 2. a detail of an arrangementof the bridge, in Figs. 3" and'4'other embodiments of the invention.

In the arrangement'shown in Fig. l a, string ,3 is stretched between two frame parts'I; 2 over two sets of rollers a1, a2, a3. a4 and b1, be, be, D4. The string 3' is fixed at 4 on the frame I and is guided consecutively overthe rollers b1. .121, D2 and soon until his "fixed'either" below the. roller a4 upon a'tuning' key, or tea weight'or any other force acting upon the end of the'string'. The distances between'the two sets of rollers are such,

that the" lengths of the" respective string parts stretched byy'aforce additionallyreduced by the friction of rollerbi; and so on.

Anequalization of. the stretching: forces may be obtained by-sounding, the strings, whereinsthe oscillations producedpractically perfectly equalize'the tension of all the stringparts.

If one frame part is used, where the line connecting the centres of therespectiveroller set is perpendicular to the; stringparts, twostrlng parts are always of the same length. If it is desired that every string part should cover a different tone, it is necessary toprovide bridgesv 101,122 p8 near one of the roller sets. As the angle, by which thestringpasses over the bridge.

does not differ much from the pressureof.

thestring upon. the bridge issmall, so thatthe bridges do not substantially increase the friction.

To make the equalization of. the tension of different string parts easier, it is possible to bring said bridges out offcontact with the string portions just for the time necessary for the equalization of thetension which may be carried out, for instance,,by sounding, the strings. An example of such an arrangement/is shown diagrammatically in Fig. 2.

The framepartZ carries theroller I), over which the string .3'is stretched in the manner as described with reference to Fig. l. The bridge p is arranged on ledge 5 held by'a bracket 6, fixed by means of hinges I to the frame 2. A helical spring B'Qctingupon this bracket'fi and guided by. thebolt I, provided. with a nut, is pressing this bracket against the frame 2 and brings simul taneously the bridge p in' engagement 'with the string 3'. By'overcoming' the pressure of the spring 8 by acting upon the bracketfiin th'e'direction of the'arrow',.the bridge"p may be removed from engagement withthe string. After equalizationof the tension of the'different string parts, the bridges '10 may be again broughtinto engagement withthestring 3.

Instead of the string 3 being fixed atone end and stretched bysome force-at the otherend, it "is possible to fixboth ends of the string on one frame part, carrying one set of rollers. Fig. 3 showssuch an arrangement. The'frame'parts I and '2 each carry'one'of the roller'sets a and b respectively. The-ends of thestring- 3-are fixed at the

points

4 and 10 on the-frame part I. The bridges p1, p2 of the frame part 'I which is'slidable against the frame part 2 in the direction of the pull of the strings. The frame partZ'is fixed whileon the frame part I a force Facts in the" downward direction to stretch the respective string parts. In some cases this force P may berepresented by the weight of the frame part I with its'accessories. Thus the" same effect may be 'obtalned as m are arranged on'extensionsin Fig. 1, but the effect of the frictional resistance of the rollers is minimized, and both ends of the string are fixed.

Instead of using two frame parts one of which is slidable with respect to the other in the direction of the pull of the strings, both frame parts may be arranged pivotally with respect to each other and held apart by a stable force. Fig. 4 shows such an arrangement. The frame parts I and 2 carry again each one roller set a and b respectively. Both frame parts I and 2 are pivotally connected and may be turned around the pivot II. The ends of the string 3- are fixed in the places 4 and It on the frame part i and guided consecutively over the roller sets a and b. Bridges p1 pa are arranged on an extension of the frame part I and a force P acts in the direction of the indicated arrows to hold both frame parts apart. In other respects this arrangement acts in the same Way as the arrangement described in the foregoing. It is to be noted that while in Figure 3 one frame part is slidably arranged with respect to the other, whereas in Figure 4 such frame parts are pivotally connected to each other, the common character of both these frames resides in that the said parts are collapsably arranged with respect to each other.

The bridges pi, 192 shown in Figs. 1, 3 and 4, may be replaced by rollers, thus reducing still more their effect upon the tension of the string and providing fo' more easily equalizing the tension.

When using a string stretched according to any of the methods described, it is possible to change the pitch of all strings simultaneously by increasing or decreasing their tension, whereby the ratio of their lengths remains constant. The sounding of the strings may be done in any known way, for example, by a keyboard.

t is obvious, that the arrangement as described may be changed in many ways within the scope of the invention. It is, for instance, possible to use no bridges at all and arrange the rollers at such a distance, that the distances between the rollers determine the length of the individual string parts only. If each string 1: rt has to be used for a different frequency, the connecting lines of the centers of the rollers must not be at a right angle to the respective string parts. Instead of individual bridges a common bridge may be used for all parts of a string. Similarly there may be the possibility of adjusting the active length of each string part by adjusting the position of the bridge.

All of the above discussed embodiments are considered to be understood by those skilled in the art to which the present invention is a contribution.

Instruments of this kind show a high degree of stability, the different string parts are influenced by outside conditions in the same way, so that they react to those influences equally and said string parts do not become mutually out of tune by any changes of moisture of the air, or by differences of temperature. The tuning if required at all is done quickly and effectively.

Having now particularly described and ascertained the nature of my said invention, and in what manner the same is to be performed, I declare, that what I claim is:

1. A string instrument, comprising in combination, a frame including two parts pivotally connected to each other; two sets of rollers arranged on said parts, respectively, opposite to each other, the distances between a roller of one of said sets and the opposite roller of the other one of said sets forming an increasing progression; a string having the ends thereof secured to one or" said parts and forming a zig-zag line engaging alternately a roller of one of said sets and a, roller of the other one of said sets so as to be subdivided into succeeding ortions having increasing lengths; and means for exerting a force on said parts of said frame urging said parts asunder whereby the portions of said string are tensioned so as to produce frequencies in the ratio of the lengths of the portions of said string.

2. A frame for use in a, stringed musical instrument, comprising two distinct parts adjustably arranged with respect to each other, two sets of rollers rotatably arranged on said parts, respectively, opposite to each other, the distances between a roller of one of said sets and the opposite roller of the other one of said sets forming an increasing progression, a vibratable string having both its ends secured to one of said parts and forming a zig-zag line engaging alternately a roller of one of said sets and a roller of the other one of said sets so as to be subdivided into succeeding portions having lengths corresponding to their frequencies of vibration and means for simultaneously stretching all of said portions so as to produce frequencies in the ratio of the lengths of said portions.

A frame for use in a stringed musical instrument, comprising two distinct parts adjustably arranged with respect to each other, one of said parts carrying a pm at one of its ends and a tuning key at its other end, two sets of rollers rotatably arranged on said parts, respectively, opposite to each other, the distances between a roller of one of said sets and the opposite roller of the other one of said sets forming an increasing progression, a vibratable string having its ends fixed on said pin and on said key, respectively, and forming a zig-zag line engaging alternately a roller of one of said sets and a roller of the other one of said sets so as to be subdivided into succeeding portions having lengths corresponding to their frequencies of vibration.

4. A frame for use in a stringed musical instrument, comprising two distinct parts collapsably arranged with respect to each other, two sets of rollers rotatably arranged on said parts, respectiveiy, opposite to each other, the distances between a roller of one of said sets and the opposite roller of the other one of said sets forming an increasing progression, a vibratable string having both its ends secured to one of said parts and forming a zig-zag line engaging alternately a roller of one of said sets and a roller of the other one of said sets so as to be subdivided into succeeding portions having lengths corresponding to their frequencies of vibration and means for exerting a force on said parts of said frame urging said parts asunder whereby the portions of said string are tensioned so as to produce frequencies in the ratio of the lengths of the portions of said string.

5. A frame for use in a stringed musical instrument, comprising two distinct parts arranged for translatory motion with respect to each other, two sets of rollers arranged on said parts, respectively, opposite to each other, the distance between a roller of one of said sets and the opposite roller of the other one of said sets forming an increasing progression; a string having the ends thereof secured to one of said parts and forming a zig-zag line engaging alternately a roller of one of said sets and a roller of the other one of said sets so as to be subdivided into succeeding portions having increasing lengths, and means for exerting a force on said parts of said frame urging said parts asunder whereby the portions of said string are tensioned so as to produce frequencies in the ratio of the lengths of the portions of said string.

6. A frame for use in a stringed musical instrument comprising two distinct parts collapsably arranged with respect to each other, two sets of rollers rotatably arranged on said parts, respectively, opposite to each other, the distances between a roller of one of said sets and the opposite roller of the other one of said sets forming an increasing progression, a vibratable string having both its ends secured to one of said parts and forming a zig-zag line engaging alternately a roller of one of said sets and a roller of the other one of said sets so as to be subdivided into succeeding portions having lengths corresponding to their frequencies of vibration, bridges ar- REFERENCES CITED The following references are of record in the file of this patent:

FOREIGN PATENTS Number Country I Date 2,512 Great Britain June 5, 1801 304,862

Germany Apr. 12, 1918