Musical instrument string and sports racket string, and method for producing said string

Abstract

Musical instrument string or sports racket string, comprising a core which comprises or is composed of a bundle of thermoplastic fibers, wherein at least some thermoplastic fibers of the bundle are at least partially, such as for example in a punctiform or linear manner, connected to one another in a materially integral manner, in particular by fusing on the boundary surfaces, and method for producing said string.

Claims

1. A string for a musical instrument or sports racket, comprising a string core, said string core further comprising a bundle of thermoplastic fibers with at least some said thermoplastic fibers of said bundle are partially-connected to one another in a materially integral manner by fusing the boundary surfaces of adjacent said thermoplastic fibers in a punctiform or linear manner wherein the elongation of said thermoplastic fibers at room temperature and at maximum tensile loading is less than 20%, and the elongation at break of said thermoplastic fibers is less than 25%.

2. The string of claim 1, further comprising said bundle of said thermoplastic fibers forms an inherently bonded flexible strand.

3. The string of claim 1, wherein said string core comprises a plurality of said bundles of said thermoplastic fibers, wherein said bundles of thermoplastic fibers form a plurality of inherently bonded flexible strands.

4. The string of claim 1 further comprising said thermoplastic fibers are highly oriented.

5. The string of claim 1 further comprising said thermoplastic fibers of said bundle are twisted in single-ply or two-ply form.

6. The string of claim 1 further comprising at least one of said thermoplastic fibers has a core/casing structure further comprised of a fiber core and a fiber casing.

7. The string of claim 6, further comprising said fiber core of said core/casing structure comprises a first thermoplastic material, and said fiber casing of said core/casing structure comprises a second thermoplastic material.

8. The string of claim 6, further comprising the volumetric proportion of said fiber casing of said core/casing structure is one of less than 60% by volume, less than 30% by volume, and less than 20% by volume.

9. The string of claim 7, further comprising said fiber casing contains solid matter particles of ferromagnetic particles or ferrimagnetic particles.

10. The string of claim 9, further comprising said solid matter particles have a primary particle diameter which is less than 500 nm.

11. The string of claim 7, further comprising said first thermoplastic material and said second thermoplastic material are identical.

12. The string of claim 1 further comprising said thermoplastic fibers comprise one of polyaryletherketone (PAEK), polyetheretherketone (PEEK), polyamide (PA), polyimide (PI), polyphenylene sulfide (PPS), and polyvinylidene fluoride (PVDF).

13. The string of claim 1 further comprising at least one sheathing disposed or wound helically about said string core and said sheathing comprises at least one plastic material or at least one metal.

14. A method for producing a string for a musical instrument or sports racket, comprising: orienting thermoplastic fibers into a bundle such that the elongation of the thermoplastic fibers at room temperature and at maximum tensile loading is less than 20%, and the elongation at break of the thermoplastic fibers is less than 25%; creating a string core by arranging the bundle of thermoplastic fibers; at least partially connecting some of thermoplastic fibers to one another by fusing the boundary surfaces of adjacent thermoplastic fibers in a punctiform or linear manner by heating the bundle of thermoplastic fibers continuously or in a batch-wise manner with a magnetic induction installation.

15. The method of claim 14, wherein at least one of the thermoplastic fibers has a core/casing structure of a fiber core and a fiber casing wherein when heating the thermoplastic fibers having the core/casing structure at least the fiber casing is heated and at least slightly fused on account of the heating from the magnetic inductive installation.

16. The method of claim 15, wherein thermoplastic fibers without a core/casing structure are at least partially fused and connected in a materially integral manner to the fiber casings of surrounding thermoplastic fibers having the core/casing structure.

17. The method of claim 14, wherein heating of the thermoplastic fibers by the induction heating installation sets the tension within the thermoplastic fibers.

18. The method of claim 14, wherein the thermoplastic fibers are conjointly twisted prior to fusing.

19. The method of claim 14, wherein the string core is formed from a plurality of bundles that are arranged to form a single strand.

20. The method of claim 14 wherein the surface of the string core is sanded and/or polished by machining.

21. The method of claim 14 wherein the string core is provided with a first sheathing helically wound about the string core and the first sheathing is from one of a round wire, a flat wire, and a polymer monofilament.

22. The method of claim 21, wherein the string core is provided with at least one other sheathing that is helically wound so as to be parallel or crossed about the first sheathing and the at least one other sheathing is from one of a round wire, a flat wire, and a polymer monofilament.

Description

(1) Further features and advantages of the invention are derived from the appended claims and from the description hereunder in which a plurality of exemplary embodiments of the invention are explained by means of the schematic drawings in which:

(2) FIG. 1 shows a cross-sectional view of an individual thermoplastic fiber having a core/casing structure of the string core of a string (musical instrument string or sports racket string) according to one particular embodiment of the present invention;

(3) FIG. 2 shows a cross-sectional view of a bundle of thermoplastic fibers having the core/casing structure of the string core of a string (musical instrument string or sports racket string) according to one further particular embodiment of the present invention in a preliminary product stage;

(4) FIG. 3 shows a cross-sectional view of a bundle of thermoplastic fibers having the core/casing structure of the string core of a string (musical instrument string or sports racket string) according to one further particular embodiment of the present invention, after heating and fusing together the individual thermoplastic fibers at least partially along the boundary surfaces;

(5) FIG. 4 shows a cross-sectional view through a plurality of bundles (a plurality of individual strands, in the present case seven) of thermoplastic fibers of FIG. 3;

(6) FIG. 5 shows a cross-sectional view or a plurality of bundles (a plurality of individual strands, the present case nineteen) of thermoplastic fibers of FIG. 3;

(7) FIG. 6 shows a cross-sectional view of a multiplicity of thermoplastic fibers with and without the core/casing structure of the string core of a string (musical instrument string or sports racket string) according to one particular embodiment of the present invention in a preliminary product stage;

(8) FIG. 7 shows a cross-sectional view of a string core from a plurality of thermoplastic fibers with and without a core/casing structure and fibers, composed of one further material, one string (musical instrument string or sports racket string) according to one further particular embodiment of the present invention in a preliminary product stage; and

(9) FIG. 8 shows a partial longitudinal sectional view of a musical instrument string according to one particular embodiment of the present invention.

(10) The thermoplastic fiber 10 illustrated in FIG. 1 in this example has a circular cross section and a core/casing structure, wherein the fiber core 12 is composed of a first thermoplastic material, and the fiber casing 14 is composed of a second thermoplastic material and ferromagnetic particles incorporated therein, only some of said ferromagnetic particles being identified by the reference sign 16. The ferromagnetic particles in this example are uniformly distributed exclusively in the fiber casing.

(11) FIG. 2 shows a string core 18 which is being created and is composed of a plurality of thermoplastic fibers 10 as are shown in FIG. 1. The thermoplastic fibers 10 in the stage shown in FIG. 2 are not yet connected to one another. In FIG. 3, the thermoplastic fibers 10 shown in FIG. 2 in the longitudinal direction are at least partially fused together on the boundary surfaces 20. The fusing together can take place, for example, by running through a magnetic induction installation (not shown). On account of the ferromagnetic particles 16, the fiber casing 14 is exclusively heated when running through the induction installation and is at least partially fused as well as connected in a materially integral manner to directly neighboring thermoplastic fibers. The thermoplastic fibers form a bundle 22. On account of the fiber casing being heated exclusively, the high mechanical strength properties of the fiber core that have been achieved in the orientation process are preserved.

(12) A string core 18 of a string is shown being created in FIG. 4. Said string core 18 is composed of a plurality of bundles 22 according to FIG. 3, and each bundle 22 forms an inherently bonded flexible strand. While the string core 18 in FIG. 4 is assembled from seven bundles 22, or strands, respectively, the string core 18 in FIG. 5 is even composed of nineteen bundles 22 of this type.

(13) FIG. 6 shows a string core 18 of a string being created. Said string core 18 comprises thermoplastic fibers to having a core/casing structure as well as thermoplastic fibers 11 without said core/casing structure.

(14) In the variant shown in FIG. 7, the string core 18 of a string comprises thermoplastic fibers to having a core/casing structure as well as thermoplastic fibers 11 without a core-casing structure and fibers 24 which are composed of a further material, for example a metal, glass, or a non-thermoplastic plastics material.

(15) FIG. 8 finally shows a musical instrument string 26 having a string core 18, the composition thereof not being illustrated in more detail, as well as having a first sheathing 28, a second external sheathing 30 that surrounds the first sheathing 28, and an external third sheathing 32 that surrounds the second sheathing 30. The first sheathing 28 and the second sheathing 30 are in each case composed of a wrap-spun arrangement of metallic round wire or polymer monofilament, while the third sheathing 32 is composed of a wrap-spun arrangement of metallic flat wire or polymer tape.

(16) The features of the invention that have been disclosed in the above description, in the drawings, as well is in the claims, can be relevant to the implementation of the invention in the various embodiments thereof individually as well as in the arbitrary combinations.

LIST OF REFERENCE SIGNS

(17) 10 Thermoplastic fiber 11 Thermoplastic fiber 12 Fiber core 14 Casing 16 Particles 18 String core 20 Boundary surfaces 22 Bundle 24 Fibers 26 Musical instrument string 28 First sheathing 30 Second sheathing 32 Third sheathing