INTERDENTAL BRUSH HAVING AN OVAL WIRE CROSS SECTION, AND METHOD FOR PRODUCING THE SAME

Abstract

The present invention relates to an interdental brush (1, 1) having a brush part (2) comprising two twisted-together legs (4A, 4B) of a wire section (4) and brush filaments (5) held clamped between the legs (4A, 4B), and to a method for producing such an interdental brush (1, 1). In order to improve in particular the bending fatigue strength of the wire section (4), it is provided according to the invention that a wire section (4) made of an austenitic steel is used which has a chromium content of 15 to 17 wt. %, a manganese content of 12 to 16 wt. % and a molybdenum content of 0 to 4 wt. %, and that the wire section (4) is formed with an oval cross-section having an ovality O in a range between 0.4 to 0.9, wherein the ovality O is dimensioned as a ratio between a length (LQk) of a small transverse axis (Qk) to a length (LQg) of a large transverse axis (Qg) of the cross-section.

Claims

1-12. (canceled)

13. An interdental brush with a brush part comprising two twisted-together legs of a wire section and brush filaments held clamped between the legs whereby the wire section is made of an austenitic steel having a chromium content of 15 to 17 wt. %, a manganese content of 12 to 16 wt. %, a molybdenum content of 0 to 4 wt. %, and comprises an oval cross-section having an ovality in a range between 0.4 to 0.9, wherein the ovality is dimensioned as a ratio between a length of a small transverse axis to a length of a large transverse axis of the cross-section, and a wire of the wire section comprises an elliptical origin cross-section, wherein a ratio of a length of a major semi-axis of the ellipse to a length of a minor semi-axis of the ellipse is between 1.4 and 1.6.

14. The interdental brush according to claim 13, whereby the twisted legs comprise turns having a turn length, measured parallel to a longitudinal axis of the brush, which is smaller than 1.5 times a maximum outer diameter of the wire section.

15. The interdental brush according to claim 13, whereby a depth of the turns measured as a difference between the maximum outer diameter and a minimum inner diameter is smaller than 0.05 to 0.2 times the maximum outer diameter.

16. The interdental brush according to claim 13, wherein the ratio of the length of the major semi-axis of the ellipse to the length of the minor semi-axis of the ellipse is between 1.5 and 1.55.

17. The interdental brush according to claim 13, whereby a number of brush filaments per turn is greater than 10.

18. The interdental brush according to claim 13, whereby a useful length of the brush filaments measured transversely to the longitudinal axis of the brush between an outer contour of the twisted wire section and a free end of the brush filaments is between 3.8 and 16 times the maximum outer diameter.

19. The interdental brush according to claim 13, whereby a ratio between the maximum outer diameter and/or a maximum wire diameter of the wire and a maximum filament diameter of the brush filaments is between 4 and 4.6.

20. The interdental brush according to claim 13, whereby a free brush end comprises a rounding and a maximum rounding diameter of the rounding is larger than the maximum outer diameter.

21. The interdental brush according to claim 13, whereby the austenitic steel comprises a nitrogen content of 0.5 wt. %, a silicon content of 0.25 wt. %, a carbon content of 0.11 wt. % and a nickel content of less than 0.05 wt. %.

22. A method for producing an interdental brush, comprising for producing a brush part of the interdental brush two legs of a wire section are twisted together and brush filaments held between the legs are clamped, whereby the wire section made of an austenitic steel comprising a chromium content of 15 to 17 wt. %, a manganese content of 12 to 16 wt. % and a molybdenum content of 0 to 4 wt. % is used, and the wire section is formed with an oval cross section having an ovality in a range between 0.4 to 0.9, the ovality being dimensioned as a ratio between a length of a small transverse axis to a length of a large transverse axis of the cross section.

23. The method according to claim 22, whereby the brush part is stretched along the longitudinal axis of the brush after twisting.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] For a better understanding of the present invention, reference is made in the following to the drawings enclosed herewith. These merely show possible examples of embodiments of the object of the invention, whereby its features, as described above, can be combined with one another or omitted as desired according to the respective requirements.

[0028] It shows:

[0029] FIG. 1 a schematic perspective view of an interdental brush according to the invention;

[0030] FIG. 2 a schematic side view of a brush part of the interdental brush shown in FIG. 1;

[0031] FIG. 3 a schematic cross-sectional view of an untwisted wire section of the interdental brush shown in FIGS. 1 and 2;

[0032] FIG. 4 a schematic cross-sectional view of a brush filament of the interdental brush shown in FIGS. 1 to 3;

[0033] FIG. 5 a schematic side view of a brush part of a further embodiment of an interdental brush according to the invention;

[0034] FIG. 6 a schematic cross-sectional view of an untwisted wire section of the interdental brush shown in FIG. 5;

[0035] FIG. 7 a schematic cross-sectional view of a brush filament of the interdental brush shown in FIGS. 5 and 6;

[0036] FIG. 8 a schematic side view of a detail of an interdental brush according to the invention;

[0037] FIG. 9 a schematic cross-sectional view of the interdental brush shown in FIG. 8 along the line of intersection A-A drawn in FIG. 8;

[0038] FIG. 10 a schematic cross-sectional view of twisted wire sections of an interdental brush according to the invention; and

[0039] FIG. 11 a schematic perspective view of a device for measuring buckling resistance forces of interdental brushes according to the invention.

WAYS TO CARRY OUT THE INVENTION

[0040] FIG. 1 shows a schematic perspective view of an interdental brush 1 according to the invention with a brush part 2 and a handle part 3, which is accommodated in a handling device 3A. The brush part 2 comprises a wire section 4 to which brush filaments 5 are held. At least brush part 2 and handle part 3 extend substantially parallel to a longitudinal brush axis L of the interdental brush 1.

[0041] FIG. 2 shows a schematic side view of the brush part 2 of the interdental brush 1 shown in FIG. 1. Here it is clear that the brush filaments 5 extend radially away from the wire section 4, running essentially perpendicular to the longitudinal axis L of the brush. At the same time, the brush filaments 5 together form a kind of spiral winding around the wire section 4. An outer diameter DB of the brush part 2 measured transversely to the longitudinal axis of the brush is approximately 2.5 mm in the embodiment example of the interdental brush 1 shown in FIG. 2.

[0042] FIG. 3 shows a schematic cross-sectional view of a wire section 4A, 4B of the interdental brush 1 shown in FIGS. 1 and 2 in an untwisted state U. The untwisted wire section 4A, 4B of the interdental brush 1 has an elliptical cross-sectional shape. In the present embodiment example, a major semi-axis of the ellipse has a length LHg of about 0.26 mm, while a minor semi-axis of the ellipse has a length LHk of about 0.17 mm.

[0043] FIG. 4 shows a schematic cross-sectional view of one of the brush filaments 5 of the interdental brush 1 shown in FIGS. 1 to 3. In the present embodiment, the brush filament 5 has a cross-section with a filament diameter DF of approximately 0.0635 mm.

[0044] FIG. 5 shows a schematic side view of a brush part 4 of a further embodiment of an interdental brush 1 according to the invention. Here it is again clear that the brush filaments 5 extend radially away from the wire section 4, running essentially perpendicular to the longitudinal axis L of the brush. At the same time, the brush filaments 5 together form a kind of helix or helix winding around the wire section 4. An outer diameter DB of the brush part 2 measured transversely to the longitudinal axis of the brush is approximately 2.2 mm in the embodiment example of the interdental brush 1 shown in FIG. 5.

[0045] FIG. 6 shows a schematic cross-sectional view of the wire section 4A, 4B of the interdental brush 1 shown in FIG. 5 in the untwisted state U. The untwisted wire section 4A, 4B of the interdental brush 1 also has an elliptical cross-sectional shape. In the present embodiment example, a large half-axis of the ellipse has a length LHg of about 0.23 mm, while a small half-axis of the ellipse has a length LHk of about 0.15 mm.

[0046] FIG. 7 shows a schematic cross-sectional view of a brush filament 5 of the interdental brush 1 shown in FIGS. 5 and 6. In the present embodiment example, the brush filament 5 has a cross-section with a filament diameter DF of approx. 0.0508 mm.

[0047] FIG. 8 shows a schematic side view of a detail of the interdental brush 1, 1 according to the invention. The wire section 4 is in a twisted state V with its legs 4A, 4B, in which the legs 4A, 4B together with brush filaments 5 held clamped between them wind spirally about the longitudinal axis L of the brush. In the present embodiment, a turn length S of the turns measured substantially parallel to the brush longitudinal axis L is smaller than 1.5 times a maximum outer diameter DD of the wire section 4.

[0048] Furthermore, the brush filaments 5 have a useful length LN with which they extend radially away from the wire section 4 in the twisted state V, measured essentially perpendicularly to the longitudinal axis L of the brush. Advantageously, the useful length LN is between 3.8 and 16 times the maximum outer diameter DD of the wire section 4. Preferably, the useful length LN is between 4 and 10 times the maximum wire diameter. Furthermore, a free brush end 6 is provided with a rounding 7, which is formed, for example, by upsetting and/or other plastic deformation, preferably as cold deformation, in order not to damage the brush filaments, which are generally made of a synthetic material.

[0049] FIG. 9 shows a schematic cross-sectional view of the interdental brush 1, 1 shown in FIG. 8 along the section line A-A drawn in FIG. 8. Here it is clear that the rounding comprises a rounding diameter DA measured perpendicular to the longitudinal axis L of the brush, which exceeds the maximum outer diameter DD of the wire section 4. A seam 8 formed between the legs 4A, 4B in the twisted state V has a depth T measured perpendicular to the brush longitudinal axis L, which is a difference between the maximum wire diameter DD and a minimum diameter or inner diameter Di of the wire section 4 measured at the bottom of the seam 8.

[0050] FIG. 10 shows a schematic cross-sectional view of the legs 4A, 4B of the interdental brush 1, F in the twisted state V. Here it is clear that the legs 4A, 4B each comprise an oval cross-section with a large transverse axis Qg and a small transverse axis Qg with a length LQg and LQk respectively. An ovality O of the cross section, measured as the ratio between the length LQk of the small transverse axis Qk to the length LQg of the large transverse axis Qg, is preferably between 0.4 and 0.9.

[0051] FIG. 11 shows a schematic perspective view of a device 100 for measuring buckling resistance forces FW of the interdental brush 1, 1. The interdental brush 1, F is held fixed with its handle part 3A in a holder (not shown), which in turn is movable relative to the device 100 in a direction substantially parallel to the longitudinal axis L of the brush. The device comprises a punch 101, a receiving plate 102 and two clamping jaws 103A, 103B. The plunger 101 is fixed in a received manner in the receiving plate 102. The receiving plate 102 is held clamped between the clamping jaws 103A, 103B.

[0052] The free brush end 6 rests on top of the plunger 101. With the aid of the plunger 102 and/or the receiving plate 102, a buckling force FK directed substantially parallel to the brush longitudinal axis L and acting on the free brush end 6 can be measured, which is counteracted by a buckling resistance force FW applied by the interdental brush 1, F or its brush part 2 when the interdental brush 1, F is moved in the direction of the device 100. If the buckling force FK exceeds the buckling resistance force FW, the wire section 4 of the brush part 2 buckles.

[0053] The buckling resistance force FW can be used as an indicator for the flexural fatigue strength of the interdental brushes 1, F or their wire section 4. The buckling resistance force FW and the flexural fatigue strength should generally be proportional to each other. In other words, the higher the buckling resistance force FW, the higher the bending fatigue strength of the wire section 4.

[0054] Buckling tests carried out with the device 100 have shown that interdental brushes 1, F according to the invention produced from wires with an elliptical original cross-section apply significantly higher buckling resistance forces FW than interdental brushes produced according to the prior art from wires with round cross-sections. For example, interdental brushes 1, F according to the invention, which are produced from an elliptical wire, the cross-section of which has a small semi-axis with a length LHk of 0.15 mm and a large semi-axis with a length LHg of 0.25 mm, produce buckling resistance forces FW of 2.52 Newton on average, with a measured minimum value of 2.17 Newton, a measured maximum value of 2.69 Newton and a standard deviation of 0.19 Newton. In contrast, with a wire diameter of 0.18 mm from the wire cross-sectional area, comparable interdental brushes with a round wire cross-section according to the prior art only generate buckling resistance forces FW of 1.63 Newton on average with a measured minimum value of 1.58 Newton, a measured maximum value of 1.70 Newton and a standard deviation of 0.05 Newton. Consequently, interdental brushes 1, 1 according to the invention are clearly superior to interdental brushes according to the prior art in terms of the buckling resistance forces FW applied by them and therefore also in terms of their flexural fatigue strength.

[0055] Modifications of the above-described examples are possible within the scope of the invention.