Patent Description:
Harps are well known musical instruments. A harp comprises a body, a neck, a post and strings. One end of the neck is connected to an upper part of the body. The other end of the neck is connected to an upper part of the post. The post is connected at its lower end to the body. The body forms a long case having a top known as a soundboard. The strings are attached at one end to the neck. The strings are attached at their other end to the body, typically via a strip member. The neck of the harp has a plurality of tuning pins. The strings are attached to these tuning pins. During playing of a harp, the strings are plucked to cause the strings to vibrate at different frequencies. The vibrations are transferred to the body which acts as a soundboard to provide the required tone from each of the strings. The frequency of vibration of the strings of given material properties varies with the vibrating length and tension of the strings. <CIT> discloses that there are a number of known devices for altering the frequency of vibration of the strings. As disclosed in the USA patent, the known devices operate by shortening the vibrating length of the strings and they have various disadvantages.

<CIT> teaches an electrified harp design which is simultaneously reliable, lightweight, low in cost, hum-free, feedback-resistant, and reproducible in quantity without excessive requirements of skill in workmanship. The harp taught increases the vibrational length of a string, however, teaches a method wherein the sting is abutted by a cam to stretch the string. Consequently, <CIT> teaches a harp which does not overcome known problems of distortion of the harp frame by torsional forces and decreased string lifespan.

<CIT> teaches a method and apparatus to hold a string of a stringed instrument and allow for precise tuning of the string as chose by the user. Concordant with <CIT>, <CIT> is silent with respect to solving known problems of distortion of the harp frame by torsional forces and decreased string lifespan.

It is an aim of the present invention to provide apparatus which reduces the disadvantages of the known different types of apparatus.

Accordingly, in one non-limiting embodiment of the present invention there is provided apparatus for lengthening the vibrating length of strings on a harp, which apparatus comprises;.

The apparatus of the present invention operates by lengthening the length of strings on a harp, as compared to the known apparatus which operates by shortening the vibrating length of strings on a harp. With the apparatus of the present invention, the lengthening is effected by stretching the stings. The degree of lengthening is small and is that required to increase the tension in the strings and thereby increase the frequency of a musical note that is able to be played by the strings.

The apparatus may be one in which, in use, the string non-lengthening position is one in which the string vibrates at non-adjusted frequency on the harp, and in which the string lengthening position is one in which the string is increased in length to increase tension in the string and thereby increase the frequency of a musical note that is able to be played by the string.

The apparatus may be one in which the securing locations are preferably holes. Other types of securing locations may be employed.

Preferably, the apparatus is one in which the securing locations are all in a straight line, and in which the adjuster members are of different shapes, with the different shapes increasing the length of the strings by different amounts. The securing means is preferably a securing plate. Securing means other than a securing plate may be employed.

The mounting means may comprise a pair of apertured lugs arranged one at each end of the apparatus. Other types of mounting means may be employed. When the mounting means is the pair of apertured lugs, then there may be one aperture in each lug. More than one aperture in each lug may be employed.

Preferably, when the securing means is a securing plate, then the lugs are formed as an integral part of the securing plate. Thus the securing means and the lugs are able to be formed as a single plate member which facilitates making the apparatus in a simple and cost-effective manner.

The apparatus may include fine tuning means. The apparatus may be one in which the fine tuning means is a screw which in use is located in a frame of the harp, and which has a head for abutting against the adjuster means. The screw is able to be screwed in or out in order to provide the fine tuning of the adjuster means. Other types of fine tuning means may be employed.

The present invention also extends to a harp when provided with the apparatus of the present invention.

Embodiments of the invention will now be described solely by way of example and with reference to the accompanying drawings in which:.

Referring to <FIG>, there is shown a harp <NUM> as disclosed in <CIT>. The harp <NUM> has a body <NUM>, a neck <NUM>, a post <NUM> and strings <NUM>. The neck <NUM> is connected at one end <NUM> to the upper end <NUM> of the body <NUM>. The other end <NUM> of the neck <NUM> is connected to the post <NUM> as shown. The post <NUM> has a lower end <NUM> which is connected to the lower end <NUM> of the body <NUM>. The strings <NUM> are connected at their upper ends to tuning pins <NUM>. The strings <NUM> are connected at their lower ends to a strip member <NUM> which is in turn connected to the face <NUM> of the body <NUM> as shown.

As shown in <FIG>, the neck <NUM> is provided with bridge pins <NUM>. There is one bridge pin <NUM> for each tuning pin <NUM>. Each bridge pin <NUM> has a tapered groove <NUM> which receives the string <NUM> and thereby precisely defines the vibrating length of the string <NUM>. The apparatus shown in the USA Patent operates by shortening the vibrating length of the strings <NUM> on the harp <NUM>. The apparatus is mounted directly below the bridge pins <NUM> for each of the strings <NUM>.

Referring now to <FIG>, there is shown first apparatus <NUM> not in accordance with the present invention. The apparatus <NUM> is for adjusting the tension in harp strings <NUM> on the harp <NUM>. The apparatus <NUM> operates by increasing the total length of the strings <NUM> and thereby increasing the tension in the strings <NUM> which increases the frequency at which the strings <NUM> vibrate. Thus the apparatus <NUM> is for increasing the length of the strings <NUM>, rather than reducing the vibrating length of the strings <NUM> as disclosed in the USA patent. In the apparatus <NUM>, the vibrating length of the strings <NUM> is kept constant by a rod member <NUM>. For ease of illustration, only one string <NUM> has been shown and only harp frame parts <NUM>, <NUM> have been shown.

The apparatus <NUM> comprises securing means <NUM> for securing one end <NUM> of the strings <NUM>. The apparatus <NUM> also comprises adjuster members <NUM> for increasing the length of the strings <NUM> in order to alter the frequency of vibration of the strings <NUM>. The apparatus <NUM> still further comprises mounting means <NUM> for mounting the apparatus <NUM> on the harp <NUM>.

There is one of the adjuster members <NUM> for each one of the strings <NUM>. The adjuster members <NUM> are pivotable adjuster members <NUM> which are pivotable between a string non-lengthening position which is shown in <FIG>, and a string lengthening position which is shown in <FIG>. The lengthening of the strings <NUM> is effected by rotating the adjuster members <NUM> in order to increase the tension in the strings <NUM>, and thereby to increase the frequency of a musical note that is able to be played by the strings <NUM>. The adjuster members <NUM> act on the securing means <NUM> for increasing the length of the strings <NUM>.

The securing means <NUM> comprises a plurality of finger members <NUM>. There is one of the finger members <NUM> for each one of the strings <NUM>. Each one of the finger members <NUM> is operated by one of the adjuster members <NUM>. The securing means <NUM> comprises a plurality of securing locations <NUM> for the strings <NUM>. There is one of the securing locations <NUM> for each one of the strings <NUM>. The securing locations <NUM> are at varying distances from the mounting means <NUM> as can be appreciated from <FIG>. The distance of each securing location <NUM> from the mounting means <NUM> determines the amount of lengthening of the string <NUM> and thereby the change in frequency of the string <NUM> and the change in the musical note that is able to be obtained from the string <NUM>. As can also be appreciated from <FIG>, the securing locations <NUM> are in the form of holes.

The securing means <NUM> is in the form of a securing plate. The adjuster members <NUM> are in the form of lever members. Each one of the lever members has a cam portion <NUM> which operates on the securing means <NUM>.

The apparatus <NUM> includes a rod member <NUM>. The adjuster members <NUM> are pivotably mounted on the rod member <NUM> as shown in <FIG> and <FIG>. Each one of the adjuster members <NUM> has a receiving slot <NUM> for receiving the rod member <NUM>.

The apparatus <NUM> includes a rod member <NUM> which acts a guide for causing the strings <NUM> precisely to engage the rod member <NUM> and thereby define exactly the vibrating length of the strings <NUM>. This overall physical length of the strings <NUM> is then only increased, for example by <NUM> - <NUM>, when it is required to increase the tension in the strings <NUM> and thereby alter the frequency of vibration of the strings <NUM>. As shown in <FIG>, there is one of the rod members <NUM>, <NUM> positioned on either side of the strings <NUM>. The mounting means comprises a pair of apertured lugs <NUM>, <NUM>. The apertured lugs <NUM>, <NUM> are arranged one at each end of the apparatus <NUM> as shown in <FIG>. There is one aperture <NUM> in each of the lugs <NUM>, <NUM>. The lugs <NUM>, <NUM> are formed as an integral part of the securing means <NUM> which is in the form of the securing plate.

The apparatus <NUM> includes fine tuning means <NUM>. The fine tuning means <NUM> is in the form of a screw having a threaded shank <NUM> which screws into the frame part <NUM> as shown in <FIG>. The fine tuning means <NUM> also has a head <NUM> which abuts against the adjuster means <NUM> as shown in <FIG> in order to provide fine tuning of the adjuster means <NUM>. This fine tuning is able to be achieved by screwing the fine tuning means <NUM> into or out of the frame part <NUM>.

The strings <NUM> are able to be connected at their ends <NUM> via the securing locations <NUM> by any suitable and appropriate fastener means. <FIG> and <FIG> show how the securing means <NUM> in the form of the plate is able to be secured to the frame part <NUM> via the mounting means <NUM> and the lugs <NUM>, <NUM>. As can be appreciated from <FIG> and <FIG>, when the adjuster members <NUM> are pushed upwardly, they push the securing means <NUM> upwardly, and this in turn stretches the strings <NUM>. <FIG> shows the illustrated adjuster member <NUM> in a sharp position. <FIG> shows the adjuster member <NUM> in a neutral position. The neutral position is also shown in <FIG> in broken lines. <FIG> shows the neutral position <NUM> in broken lines. <FIG> also shows the adjuster member <NUM> in a position between the position shown in <FIG> and the position shown in <FIG>, The adjuster members <NUM> are able to give precision adjustment of their strings <NUM>. The amount of tension to be increased can be fine tuned by the fine tuning means <NUM>, for example to give a precise semi-tone increase after installation of the apparatus <NUM> on the harp <NUM>.

In order to facilitate manufacture of the apparatus <NUM> at an optimum low cost, the adjuster members <NUM> are the same for every string <NUM>. The distance from the securing locations <NUM> to the frame part <NUM> determines the amount of tension increase to the strings <NUM> and this is different for each string <NUM>. The mounting means <NUM> in the form of the sheet metal plate is attached to the frame part <NUM> on its side as shown.

<FIG> shown second apparatus <NUM> not in accordance with the present invention. The apparatus <NUM> is basically the same as the apparatus <NUM> except that the apparatus <NUM> has been shown with specific size dimensions which are given in millimetres. Similar parts as in the apparatus <NUM> have been given the same reference numerals for ease of comparison and understanding.

In both the apparatus <NUM> and the apparatus <NUM>, it will be seen that the rod members <NUM>, <NUM> and <NUM> extend between, and are mounted on, end members <NUM>, <NUM>.

Referring now to <FIG> there is shown the apparatus <NUM> of the present invention. Similar parts as in the apparatus <NUM> have been given the same reference numerals for ease of comparison and understanding.

In the apparatus <NUM>, it will be seen that the rod members <NUM>, <NUM> from the apparatus <NUM>, <NUM> have been omitted. This can best be appreciated from a comparison of <FIG> with <FIG>. Also from a comparison of <FIG> with <FIG>, it will be seen that the adjuster members <NUM> still pivot about the rod member <NUM> but the adjuster members <NUM> do not have the receiving slots <NUM>. The adjuster members <NUM> in the apparatus <NUM> have different shapes. More specifically the adjuster members <NUM> have different cam profiles <NUM>. This compares to the single cam profile <NUM> in the apparatus <NUM>. Because the cam profiles <NUM> are different to each other, they are able to increase the length of the strings <NUM> by different amounts, and thereby alter the frequency or vibration of the strings <NUM> by different amounts.

From a comparison of <FIG> with <FIG>, it will be seen that in the apparatus <NUM>, the securing locations <NUM> are in a straight line. This compares with the curved line for the securing locations <NUM> in the apparatus <NUM>. In the apparatus <NUM>, the finger members <NUM> are still sprung finger members <NUM>. Referring to <FIG>, in use of the apparatus <NUM>, the distance <NUM> from the centre <NUM> of the cam head <NUM> of each adjuster member <NUM> to the top of the cam profile <NUM> where it touches the finger member <NUM> determines the amount of length increase and therefore tension increase for each string <NUM>. This distance is different for each string <NUM> and this different distance causes the strings <NUM> to vibrate at different required frequencies in order to obtain the different required tones from each of the strings <NUM>. Increasing the tension in a string <NUM> increases the frequency of the musical note that is produced. As in the apparatus <NUM>, <NUM>, <NUM> the amount of tension for each string <NUM> is able to be fine-tuned by the fine tuning means <NUM>. From a comparison of <FIG> and <FIG> with <FIG>, it will be seen that in the apparatus <NUM>, the shape of the finger members <NUM> as viewed from above is different from the shape of the finger members <NUM> as viewed from above in the apparatus <NUM>. The finger members <NUM> may be of other shapes.

The apparatus <NUM> of the present invention may be used to allow the frequency of individual strings <NUM> to increase by one or two semitones. The apparatus <NUM> operates by stretching the strings <NUM> instead of shortening the vibrating length. Stretching the strings increases the tension and therefore the pitch. The apparatus <NUM> provides the possibility of three pitches per string, i.e. flat, neutral and sharp. The apparatus <NUM> may be produced at a decreased cost compared with known apparatus which shortens the vibrating length of the strings. This cost reduction may be achieved by a decrease in the amounts of parts required for the apparatus of the present invention, and also in the ability to standardise some of the component parts. The apparatus <NUM> is easily adjusted by the fine tuning means <NUM>. The apparatus <NUM>, <NUM>, <NUM> is able to be robust in use and provide better fall protection because the adjuster means <NUM> in the form of the levered cams do not stick out in the neutral position shown in <FIG>.

The apparatus of the present invention allows for the strings to be centrally placed in the harp, supported equally at both sides. This may provide structural advantages, for example the absence of a resulting torque on the frame as in the non-central known apparatus, which in turn means lower material property requirements for the overall harp frame and thereby may reduce cost. Also, the strings are not mechanically pressed at one point repeatedly to shorten the vibrating length, which may result in longer string life.

The apparatus of the present invention may be produced as an inexpensive low threshold apparatus for entry level use of an electric harp, for example for children. Apparatus for changing the vibrating length of strings on a harp typically forms a major component cost part for the harp. The ability of the apparatus of the present invention to reduce this cost is a major advantage. A further advantage is the ability to change the tension in the strings as a primary mechanism for instantly shifting the pitch by semitones.

Claim 1:
Apparatus for lengthening the vibrating length of strings (<NUM>) on a harp (<NUM>), which apparatus comprises:
(i) securing means (<NUM>) for securing one end of the strings;
(ii) adjuster members (<NUM>) for increasing the length of the strings in order to increase the tension in the strings and thereby alter the frequency of vibration of the strings;
(iii) a rod member (<NUM>);
and
(iv) mounting means (<NUM>) for mounting the apparatus on the harp,
and characterised in that:
(v) the adjuster members are lever members;
(vi) there is one of the lever members for each one of the strings;
(vii) the securing means comprises a plurality of finger members (<NUM>), in which there is one of the finger members for each one of the strings of the harp, and in which each finger member is operated by one of the lever members;
(viii) the lever members have a cam portion (<NUM>) which operates the securing means;
(ix) the lever members have a receiving slot for receiving the rod member;
(x) the lever members being pivotably mounted on a rod member;
and whereby:
(xi) the lever members are pivotable adjuster members which are pivotable between a string non-lengthening position and a string lengthening position;
(xii) the lever members act on the securing means in order to increase the length of the string.