Patent Description:
Normally a musical instrument string comprising one or more layers of plastic or metal wires and/or bands wound around a core with single or multi thread(s) is played-in ("playing-in" is a commissioning process, well known by musicians playing musical string instruments) over some time from the fixing and tuning on the instrument and subsequent use of the musical instrument string during a period of time, which causes the wire(s) and/or band(s) wound around the core and/or the different layers of the musical instrument string to be seated in a stable condition, where the wanted musical quality, string response and sound is achieved. This is time consuming.

<CIT> and <CIT> disclose a method for producing a musical instrument string comprising one or more layers of wire wound around a core, in which the the musical instrument string is clamped between two fixed points with a predefined constant pull force or a variable pull force in the longitudinal direction of the musical instrument string to keep the string taut.

Accordingly, it is the aim of the present invention to provide a method and an apparatus for accelerating the process towards the stable condition and the wanted stable sound as described above.

According to the invention, this aim is achieved by a method according to claim <NUM>.

According to the invention, this aim is further achieved by an apparatus for producing a musical instrument string according to claim <NUM>.

The present invention is based on the surprising knowledge that by using a so-called flexing process a stable condition with the wanted musical quality, response and sound, can be achieved. The flexing process is used for exercising and flexibly aligning the wire(s) and/or band(s) wound around musical instrument strings with one layer or with more layers wound upon each other. Use of the flexing process will accelerate achieving the wanted musical quality, response and sound.

Further features and advantages of the present invention will be clear from the accompanying claims and the following description of special embodiments in combination with the schematic drawings, in which.

The apparatus <NUM> shown in <FIG> could be an apparatus for artificial playing in a musical instrument string <NUM> comprising one or more wire(s) and/or band(s) wound around a core according to a special embodiment of the present invention or an apparatus for producing a musical instrument string <NUM> comprising one or more layers of wire(s) and/or band(s) wound around a core according to a special embodiment of the invention or part thereof. Said apparatus <NUM> comprises a string tensioning device <NUM> for clamping the musical instrument string <NUM> between two points P1 and P2 with a pull force fixed or variable in its longitudinal direction (in <FIG> corresponding to the horizontal direction) to keep it taut and a flexing device <NUM>. The string tensioning device <NUM> comprises two fastening points e. hooks <NUM> at the point P1 and the point P2, respectively. The longitudinal ends <NUM> of the musical instrument string <NUM> are attached to said hooks <NUM>. Said hooks <NUM> are connected to two motors, in this example two servomotors <NUM>, <NUM>, for turning said hooks <NUM>, <NUM> in such a way that the musical instrument string <NUM> can be rotated around its longitudinal axis. Said servomotors <NUM> and <NUM> are configured to run synchronously, and in this example servomotor <NUM> is the master and servomotor <NUM> is the slave. The apparatus <NUM> also comprises a control device (not shown) for controlling the operation of the servomotors <NUM> and <NUM>. In this example, the flexing device <NUM> comprises three rollers <NUM>, <NUM> and <NUM> for flexing the musical instrument string <NUM> clamped between the two points P1 and P2. Said rollers <NUM>, <NUM> and <NUM> are mounted on the respective axes 26a, 28a, 30a. In this example said axes 26a, 28a and 30a are parallel to each other in a plane along the musical instrument string <NUM> and a plane perpendicular to the musical instrument string <NUM> and spaced apart. In this open condition the flexing apparatus <NUM> is moved over the musical instrument string <NUM>, so that preferably none of the rollers <NUM>, <NUM> and <NUM> touches the musical instrument string <NUM> (see <FIG>). Said flexing device <NUM> is positioned in such a way that the axes 26a, 28a and 30a and thus the rollers <NUM>, <NUM> and <NUM> are spaced laterally and longitudinally with reference to a line <NUM> collinear to the longitudinal direction of the musical instrument string <NUM> in its original position (as shown in <FIG>) and the middle of the rollers <NUM>,<NUM> and <NUM> is positioned on the level with the musical instrument string <NUM>.

As shown in <FIG>, the axes 26a, 28a and 30a and thus the rollers <NUM>, <NUM> and <NUM> are then moved in the transversal direction of the musical instrument string <NUM> towards the musical instrument string <NUM> so that the rollers touch the musical instrument string <NUM> and press against its surface, and at the same time give the musical instrument string <NUM> a defined deflection. This can be achieved, because the rollers <NUM>, <NUM> and <NUM> are configured to be positioned in such a way that the musical instrument string <NUM> is stretched alternately to one side and to the other side of the line <NUM>. In other words, as the flexing device <NUM> is placed in a defined position, the rollers <NUM>, <NUM> and <NUM> are closed around the musical instrument string <NUM> with a defined movement of said <NUM>, <NUM> and <NUM>. Furthermore, the pull force in the longitudinal direction of the musical instrument string <NUM> may be readjusted to a defined pull force or during the process running adjusted to a defined pull force by a corresponding device or means (not shown).

The flexing device <NUM> is now ready for the flexing process.

As can be seen in <FIG>, the flexing rollers <NUM>, <NUM> and <NUM> can be moved forth and back simultaneously in the direction of the line <NUM>.

After that, the flexing device is moved a defined stroke in the longitudinal direction of the musical instrument string and in a defined area of the musical instrument string. The flexing device is moved a defined number of times in a forwarding and reciprocating movement in the longitudinal direction of the musical instrument string, while the closing position of the flexing apparatus is kept constant and the pull force in the longitudinal direction of the musical instrument string is kept constant or readjusted (see <FIG>).

Furthermore - according to <FIG> - the musical instrument string <NUM> can be rotated by for example <NUM>° around the line <NUM> by way of simultaneously rotating the hooks <NUM>, <NUM> through the servomotors <NUM> and <NUM>. Said rotation can for example be done after a single pass of moving the rollers <NUM>, <NUM> and <NUM> in one direction along the line <NUM> or after a multi pass. The rollers can be kept in closed position and thus in contact with the musical instrument string or opened, so there is no contact with the musical instrument string during the rotation. The servomotors <NUM> and <NUM> rotate the hooks <NUM>, and the musical instrument string <NUM> for example <NUM>°, and the musical instrument string <NUM> is then ready for the next step in the flexing process with a defined number of forwarding and reciprocating movements (see <FIG>). For simultaneous movement of said rollers <NUM>, <NUM> and <NUM> they could be arranged on a carriage (not shown).

The flexing process is carried out on the surface of the musical instrument string <NUM> and can be carried out in the whole or part of the length of the musical instrument string <NUM>. It can be carried out on each of the different wound layers on the musical instrument string <NUM> or only on the last layer. The flexing process is carried out with the flexing device <NUM> with forwarding and reciprocating movements in the longitudinal direction of the musical instrument string <NUM> and from one or more sides.

The flexing process can be carried out in the production of musical instrument strings with one or multiple core threads, (rope) core with an arbitrary number of for example metal or plastic threads/wires or for example multifilament core with an arbitrary number of for example synthetic fibers with wound arbitrary material in one to six layers upon each other.

Already during production of the musical instrument string use of the flexing process will accelerate the stable condition, and thus the musical instrument string will be played in and achieve the desired stable musical quality, response and sound.

During production of a musical instrument string the flexing process can be carried out on an arbitrary layer of wire and/or band wound around a musical instrument string core or wound on top of earlier wound layer(s) or primarily on the last wound layer.

The flexing process is carried out while the musical instrument string is kept clamped in the longitudinal direction preferably with the defined fixed or variable pull force in the longitudinal direction preferably during the whole flexing progress.

In order to be able to make a forwarding and reciprocating flexing movement the musical instrument string is preferably held between two hooks with a defined pull force while the flexing rollers <NUM>, <NUM>, <NUM> are making forwarding and reciprocating movements controlled by the flexing apparatus/control device.

The flexing process may be carried out with more movements forwarding and reciprocating on the surface of the musical instrument string and in more positions of the musical instrument string rotated around its longitudinal axis, either with a consecutive rotation or rotation of the musical instrument string in steps between one or more flexing movements (see also <FIG>). The flexing process may be carried out with a variable adjusted flexing force (pressure from the flexing device <NUM>), which is fixed during the whole flexing process or is carried out with a variable adjusted force, which moreover can be varied during the flexing process itself. The flexing process may be carried out arbitrarily chosen one or more times forwarding and reciprocating on the musical instrument string.

The flexing process should be carried out in the whole length of the musical instrument string, in the playable area of the musical instrument string or just in one or more small arbitrary area(s) of the string.

The flexing process may be carried out while the musical instrument string is kept still (no rotation). However, the flexing process can also be carried out while the musical instrument string rotates around its longitudinal axis, or the flexing process can be carried out in turn from more sides of the musical instrument string arbitrarily rotated in the positions for example <NUM>°-<NUM>°-<NUM>°-<NUM>° between the flexing movements, preferably <NUM>° at a time.

The flexing process may be carried out with a flexing apparatus, which is working either manually or automatically.

The flexing process may be carried out with for example rollers like <NUM>, <NUM> and <NUM> which roll on the surface of the wire and/or band wound around the musical instrument string. The rollers are displaced from each other in the longitudinal direction and in the transversal direction of the musical instrument string, and are placed on two or more sides of the musical instrument string so that the rollers apply a defined force on the musical instrument string in the transversal direction and a defined bending of the musical instrument string around part of the rollers on the flexing device.

The transversal force from the rollers is defined by the number of the rollers and the position of the rollers. The transversal force on the surface of the musical instrument string can be varied by adjusting the position of the rollers between each other around the musical instrument string, the bending of the musical instrument string around the rollers on the flexing device and the pull force in the longitudinal direction of the musical instrument string.

The longitudinal force on the string, the transversal force on the string, the bending around the rollers, the number of rollers, the number of flexing movements and the flexed area on the string define how effective the process of alignment and seating of the wire(s) and/or band(s) is carried out.

The longitudinal force on the musical instrument string can be between <NUM> N to <NUM> N, preferably between <NUM> N to <NUM> N.

The flexing process is carried out with two or more flexing rollers that roll on the surface of the musical instrument string and in that way exercise the musical instrument string. The number of the rollers can be chosen from <NUM> rollers to <NUM> rollers, preferably <NUM> rollers to <NUM> rollers.

The diameter of the rollers and the longitudinal distance between the rollers as well as the overlap of the rollers perpendicularly to the longitudinal direction of the musical instrument string determine the bending of the musical instrument string and in that way how much the musical instrument string is flexed at each flexing movement (pass).

The diameter of the rollers can vary from about <NUM> to about <NUM>, preferably <NUM> to <NUM>. The diameter of the different rollers in the flexing apparatus may be the same or different.

The longitudinal distance A between the rollers center to center, as for example the rollers <NUM> and <NUM> shown in <FIG>, and where A can be between <NUM> to <NUM> (depending of the diameter of the rollers), preferably between <NUM> to <NUM>.

The overlap of the rollers perpendicularly to the longitudinal direction of the musical instrument string is defined by the transversal distance B between the rollers center to center, as for example the rollers <NUM> versus <NUM> and <NUM> shown in <FIG>, and where B can be between <NUM> to <NUM> (depending of the diameter of the rollers), preferably between <NUM> to <NUM>.

The distance C between the opposite rollers on each side of the musical instrument string, as for example the rollers <NUM> and <NUM> or <NUM> and <NUM> shown in <FIG>, and where C can be between <NUM> to <NUM> (depending of the diameter of the rollers), preferably between <NUM>,<NUM> to <NUM>.

As exemplarily shown in <FIG>, the rollers <NUM>, <NUM> and <NUM> on the flexing apparatus may be designed for example with a smooth surface, with a V-shaped track, a half-round track or a square track in the surface (shown from left to right in <FIG>). In order to reduce wear on the roller surface, the roller surface can be coated or hardened.

As shown exemplarily in <FIG>, the number of rollers may be chosen arbitrarily, and the rollers may be arbitrarily placed on two or more sides of the musical instrument string.

The flexing process may be carried out simultaneously from more sides on the musical instrument string with the flexing rollers placed at arbitrarily chosen angles in proportion to one another and still rolling on the string surface or for example in the positions <NUM> × <NUM>°, <NUM> × <NUM>°, <NUM> × <NUM>° or <NUM> × <NUM>° between the rollers <NUM>, <NUM>, <NUM>, <NUM> as exemplarily shown in <FIG>, preferably <NUM> × <NUM>° or <NUM> × <NUM>°.

The flexing process may be carried out in extension of the winding processes for each of the wound layers or as a flexing process on the surface of the finished musical instrument string, before any grinding of the surface of the musical instrument string is taking place. In an example not forming part of the claimed invention, the flexing process can be carried out during the grinding of the musical instrument string.

After one or more flexing movements (forwarding and reciprocating movements) the musical instrument string may be rotated a defined number of degrees around the longitudinal direction of the musical instrument string, and the flexing process is repeated with the defined number of flexing movements, while the closing position, the bending of the string and the pull force in the longitudinal direction of the string are kept. This process can be repeated after rotating the musical instrument string a number of degrees around the longitudinal direction of the musical instrument string. The flexing process is stopped, and the flexing apparatus is opened (see <FIG>), so that all the rollers are free of the musical instrument string, and the flexing apparatus is moved away from the musical instrument string.

By way of an example, it is explained how the musical instrument string is wound with one or more layers of wire and/or band wound upon previous layers, and then the mentioned flexing process is repeated for each layer. The finished musical instrument string is then grinded.

<FIG> show several steps of a method for producing a musical instrument string comprising one or more layers of wire(s) and/or band(s) wound around a core according to a special embodiment of the present invention. For example, the apparatus shown in <FIG> can be used for carrying out said method. In step <NUM> (see <FIG>) a core <NUM> is set up between two hooks, for example the hooks <NUM>, <NUM> shown in <FIG>. In step <NUM> a first layer <NUM> with for example round wire is helically wound on the core <NUM>, clockwise or counter-clockwise (see <FIG>). In step <NUM> (see <FIG>) the musical instrument string <NUM> with said first layer <NUM> is flexed by way of for example the apparatus shown in <FIG>. In step <NUM> (see <FIG>) the musical instrument string <NUM> is turned for example <NUM>° and the flexing process is repeated on the first layer <NUM>. In step <NUM> (see <FIG>) a second layer <NUM> with wire or band is helically wound on the first layer <NUM>. In step <NUM> (see <FIG>) the flexing process is carried out on the second layer <NUM>. In step <NUM> (see <FIG>) the musical instrument string <NUM> is turned for example by <NUM>° and the flexing process is repeated on the second layer <NUM>.

Then - in step X - (where X can be <NUM>, <NUM> or <NUM>) (see <FIG>) a further layer <NUM> wire or band can be wound on the musical instrument string <NUM>. In step X+<NUM> (see <FIG>) the flexing process is carried out on the further layer <NUM>. In step X+<NUM> (see <FIG>) the musical instrument string <NUM> is turned for example <NUM>°, and the flexing process is repeated on the further layer <NUM>. The number of layers can be from <NUM> to <NUM> layers.

Finally, as shown in <FIG>, a last layer <NUM> (which for example could be layer <NUM>) is wound with a metal band, flexed on two sides and then grinded.

<FIG> show an alternative to the method shown in <FIG>. They show the production of a musical instrument string <NUM> with two layers of wire(s) and/or band(s) and flexing on only the last wound layer. In step <NUM> (see <FIG>) a core <NUM> is setup between hooks, for example the hooks <NUM>, <NUM> of the apparatus shown in <FIG>.

In step <NUM> (see <FIG>) a first layer <NUM> with wire or band is wound around the core <NUM>. In step <NUM> (see <FIG>) a second and last layer <NUM> with metal band is wound around the musical instrument string <NUM>.

Then in step <NUM> (see <FIG>) the flexing process is carried out on the last layer <NUM>.

In step <NUM> (see <FIG>) the musical instrument string <NUM> is turned for example <NUM>°, and the flexing process is repeated on the last layer <NUM>.

Finally, as shown in <FIG>, the last layer <NUM> is grinded.

Claim 1:
Method for producing a musical instrument string (<NUM>) comprising one or more layers (<NUM>, <NUM>, <NUM>, <NUM>) of wire(s) and/or band(s) wound around a core (<NUM>), in which the method comprises carrying out a flexing process on the musical instrument string (<NUM>) while the musical instrument string (<NUM>) is clamped between two fixed points (P1, P2) with a predefined constant pull force or a variable pull force in the longitudinal direction of the musical instrument string to keep the string taut, during the production as an integrated part of the production at the winding process or after winding the last layer on the musical instrument string (<NUM>);
characterised in that the flexing process takes place before grinding of the surface of the musical instrument string (<NUM>), wherein the flexing process comprises applying a defined force on the musical instrument string (<NUM>) in a direction transversal to the musical instrument string (<NUM>) with a flexing device (<NUM>) comprising at least two spaced apart flexing elements, in which the at least two flexing elements are rollers (<NUM>, <NUM>, <NUM>);
and wherein the flexing process comprises bending the musical string around part of a roller simultaneously to both one side and to the other side of a line (<NUM>) representing the original position of the musical instrument string (<NUM>), when being clamped between said two points (P1, P2).