ROTOR BOW COMPRISING A TUBULAR GUIDE ELEMENT, PARTICULARLY FOR A MACHINE FOR PROCESSING ELONGATE STRAND MATERIAL

Abstract

Flyer bow for a wire-braiding or cable-twisting machine, comprising a bow member that has a groove extending essentially along the entire longitudinal extension of the flyer bow in the longitudinal direction of the flyer bow. The flyer bow comprises a tubular guiding element, especially a coil spring, for guiding the elongate strand-type material that is placed in the groove without interruption, essentially along the entire longitudinal extension of the groove. The inner dimensions of the groove at any point along the longitudinal extension of the guiding element are greater than or equal to the outer dimensions of the guiding element at the same point. This makes it easy to remove and introduce, preferably pull out and insert, the guiding element from and into the groove.

Claims

1. A rotor bow, particularly for a machine for processing elongate strand material, comprising a groove in the body of the rotor bow which extends in the longitudinal direction of the rotor bow substantially over the entire longitudinal extension of the rotor bow and a tubular guide element for guiding the elongate strand material, wherein the guide element is arranged in the groove without interruption and substantially over the entire longitudinal extension of the groove. wherein the internal dimensions of the groove at any one point of the longitudinal extension of the guide element are greater than or equal to the external dimensions of the guide element at that point.

2. The rotor bow according to claim 1, wherein the guide element is positively connected to the body of the rotor bow by way of the groove over at least 60%, preferably over at least 70%, further preferably over at least 75%, as well as preferably over at most 90%, further preferably over at most 80% of the longitudinal extension of the rotor bow.

3. The rotor bow according to claim 1, wherein the cross section of the groove is configured with an overall length of at most 40%, preferably at most 30%, further preferably at most 25%, as well as preferably at least 10%, further preferably at least 20% of the longitudinal extension of the rotor bow in at least one removal area such that the guide element can be removed from the body of the rotor bow at each point of the removal area in a removal direction extending perpendicular to the longitudinal extension of the rotor bow without deformation to the cross section of the guide element (4) at this point.

4. The rotor bow according to claim 3, wherein at least one removal area is arranged in the region of one of the ends of the rotor bow.

5. The rotor bow according to claim 4, whrein a respective removal area is arranged in the region of both ends of the rotor bow.

6. The rotor bow according to claim 3, wherein at least one slot is arranged at least at one point in at least one removal area in the body of the rotor bow through which the guide element can be pushed in the removal direction.

7. The rotor bow according to claim 6, wherein the at least one slot is a through hole in the body of the rotor bow.

8. The rotor bow according to claim 1, wherein the guide element is a spring, a coil spring, a Bowden cable sheath, a flexible shaft sleeve, a plastic tube, a steel tube or a hose.

9. The rotor bow according to claim 1, werein the guide element is a coil spring of wire having a substantially round cross section.

10. The rotor bow according to claim 1, wherein the guide element is a wire coil spring having a cross section which is substantially linear on the outer side of the coil spring and runs substantially parallel to the longitudinal direction of the coil spring and exhibits a curvature at the inner side of the coil spring directed toward the interior of said coil spring.

11. The rotor bow according to claim 1, wherein the guide element is a wire coil spring having a cross section which is of basic rectangular shape and the cross section exhibits a curvature on the outer side of the coil spring directed toward the exterior or interior of the coil spring and a curvature on the inner side of the coil spring directed toward the interior of the coil spring.

12. The rotor bow according to claim 1, wherein the guide element is a coil spring, the coils of which are spaced apart from one another.

13. The rotor bow according to claim 1, wherein at least the inner surface of the guide element is coated with a friction-reducing and/or anti-wear material, in particular Teflon, or provided with a friction-reducing and/or anti-wear hardening.

14. The rotor bow according to claim 1, wherein the body of the rotor bow exhibits cross sections of different shape at different points along its longitudinal extension, in particular a substantially elliptical cross section at least at one point and a substantially rectangular cross section at another point.

15. A machine for processing elongate strand material comprising a rotor bow according to claim 1.

Description

[0046] Further advantageous embodiments will follow from the description below in conjunction with the figures. Shown are:

[0047] FIG. 1:

[0048] a) a side view of a rotor bow according to the invention with associated fixing devices on the rotor of the machine;

[0049] b) a cross section through the center region of the rotor bow;

[0050] c) an enlarged view of the inlet and deflection end of the rotor bow;

[0051] FIG. 2:

[0052] a) a side view of the body of an inventive rotor bow;

[0053] b) an enlarged view of the inlet and deflection end of the rotor bow body as seen from underneath;

[0054] c) three cross sections of the rotor bow body through the center region, the intake end and the deflection end respectively;

[0055] FIG. 3:

[0056] a) an oblique view from the removal area of a section of an inventive rotor bow at the transition from the center region to a removal area during the inserting of a guide element;

[0057] b) the view of the rotor bow from FIG. 4a) with inserted guide element;

[0058] c) the view of the rotor bow from FIG. 4a) when the guide element is being pushed out of the removal area by a tool;

[0059] FIG. 4:

[0060] a) a section of a guide element in the form of a closed coil spring in oblique view and in cross section;

[0061] b) a section of a guide element in the form of an open coil spring in oblique view and in cross section;

[0062] c) four sections of guide elements in the form of wire coil springs of differing longitudinal cross sections;

[0063] FIG. 5:

[0064] a) a comparison table of power consumption values for a rotor bow according to the prior art and a rotor bow according to the invention at different twist rates;

[0065] b) depiction of the values from the FIG. 5a) table as a bar chart.

[0066] FIG. 1a shows a side view of a rotor bow 1 according to the invention having a body 2 which extends in curved form between a left inlet-side end (as the bunched or stranded elongate strand material enters into the rotor bow 1 at this end) and a right, deflection-side end (as the bunched or stranded elongate strand material is deflected at this end and led to a take-up reel). The body 2 of the rotor bow 1 consists of fiber-reinforced plastic in the example embodiment and is configured as a solid component without cavities (apart from a groove 3, fixing slots 8 and further bore holes as described further below).

[0067] The rotor bow is preferably suitable for the processing of bare, e.g. seven-wire strands, preferably of copper alloys such as CuMg, in particular CuMg02 (i.e. with a magnesium content of 0.2%), CuAg, CuSn or the like, having small cross sections of no more than 1.5 mm.sup.2, at high twist rates, preferably 6500 twists per minute (corresponding to 3250 revolutions in a double-twist bunching machine). However, other materials having other material and/or process parameters, preferably twist rates of 7000 or more twists per minute, can also be processed.

[0068] The rotor bow is further preferably applicable to machines for spools of 630 mm diameter. However, the rotor bow is also suitable for other machine sizes, whereby larger-dimensioned machine sizes generally employ lower twist rates and smaller-dimensioned machine sizes generally employ higher twist rates.

[0069] An inlet-side removal area 5 is additionally provided at the inlet end of the rotor bow 1 as is a deflection-side removal area 6 at the deflection end of the rotor bow 1, which will be described in greater detail below.

[0070] FIG. 1b shows a cross section through the rotor bow 1 at the approximate center of its longitudinal extension. At this point, the body 2 of the rotor bow 1 exhibits a substantially elliptical cross section (when disregarding the groove 3). A groove 3 is embedded at the center of a longitudinal side of the cross section. The groove 3 has a circular cross section, from which a circular section smaller than a semicircle has been cut out at the open side of the groove 3. A tubular guide element 4 of circular cross section is arranged in the groove 3. In the example embodiment, the guide element 4 consists of a coil spring wound from spring steel wire. The groove 3 has a slightly larger diameter than the guide element 4 (not discernible in the figure) such that the guide element 4 has a small amount of play in the groove 3 and can thus be pushed into or out of the groove 4 in the longitudinal direction with little effort. The groove 3 encloses the guide element 4 in the cross section by more than half such that there is a positive connection between the guide element 4 and the groove 3.

[0071] FIG. 1c shows enlarged depictions of the inlet-side removal area 5 and the deflection-side removal area 6. The rotor bow 1 is affixed to the machine rotor in these areas by different fixing devices 7. Since the fixing devices 7 are only of lesser importance in the context of the present invention, they will not be described in any greater detail here.

[0072] The rotor bow 1 and thus also the groove 3 and the guide element 4 have a longitudinal extension of approximately 1672 mm in the example embodiment. The inlet-side removal area 5 has a longitudinal extension of approximately 226 mm and the deflection-side removal area 6 has a longitudinal extension of approximately 141 mm. The width of the rotor bow, corresponding to the long axis of the substantially elliptical cross section, or the long side of the substantially rectangular cross section respectively, amounts to approximately 28 mm, and the thickness of the rotor bow, corresponding to the short axis of the substantially elliptical cross section, or the narrow side of the substantially rectangular cross section respectively, amounts to approximately 6.5 mm. The inner diameter of the groove 3 is approximately 6.2 mm and the outer diameter of the guide element 4 is approximately 6 mm. The wall thickness of the body 2 between the closed side of the groove 3 and the opposite exterior of the body 2 amounts to approximately 1.4 mm.

[0073] FIG. 2a shows an isolated depiction of the body 2 of an inventive rotor bow 1 in a side view.

[0074] Two fixing slots 8 can in each case be seen in the inlet-side removal area 5 and in the deflection-side removal area 6 on the front outer side of the body 2 depicted in FIG. 2a.

[0075] It can be seen from FIG. 2b, which shows the removal areas 5 and 6 in an enlarged depiction from underneath, two respective fixing slots 8 each of semicircular cross section are provided at the rotor bow's front side and rear side in each removal area 5, 6. A fastening clip 9 affixed to the rotor engages in these fixing slots 8 in order to secure the rotor bow 1 to the rotor. This does away with the need for further fixing elements on or in body 2 such as threading which could structurally weaken the fiber-reinforced plastic.

[0076] The body 2 of the rotor bow 1 has a substantially rectangular cross section in the respective removal areas 5, 6 and a substantially elliptical cross section in its center region between the removal areas 5, 6. This is again illustrated in the three sectional views of FIG. 2c by the center region, the inlet-side removal area 5 and the deflection-side removal area 6 respectively. However, different cross-sectional shapes are of course also possible in the respective areas.

[0077] Further seen in FIG. 2c is that the cross section of the groove 3 in the removal areas 5, 6 does not taper at the open side of the groove 3 as in the center region of the body 2 but rather exhibits straight lateral edges at the open side. This thereby enables the guide element 4 here with circular cross section to be easily inserted into and/or taken out of the removal area 5, 6.

[0078] FIG. 3 again illustrates the insertion/removal procedure for the guide element 4.

[0079] Therein, FIG. 3a shows the body 2 of a rotor bow 1 at the transition between the central region and the deflection-side removal area 6 just as the guide element 4, in this case a wire coil spring, is being inserted through the removal area 6 into the groove 3 by being pushed in toward the other end of the rotor bow 1, indicated by the arrow.

[0080] FIG. 3b shows the body 2 with a fully inserted guide element 4.

[0081] FIG. 3c shows the body 2 just as a user is manually pushing the guide element 4 out of the removal area 6. The user is using a pin-like tool 11 here, preferably a simple Allen wrench, and presses it into the groove 3 through a (not shown) bore hole connecting the groove 3 to the opposite outer side of the body 2, whereby the guide element 4 can be pushed out of the groove 3 and thus easily removed manually.

[0082] This makes it very easy to replace the guide element 4, preferably upon it becoming worn, and without any special tool being required to do so.

[0083] FIG. 4 shows two different variations of a guide element 4 configured as a coil spring, namely a closed coil spring in FIG. 4a, in which the coils are directly adjacent, as well as an open coil spring in FIG. 4b, in which there is free space between adjacent links. A respective perspective view as well as cross section are shown in each case.

[0084] FIG. 4c shows four different variations of a longitudinal section through a guide element 4 in the form of a coil spring: In the first variant (upper left representation), the cross section of the wire, from which the coil spring is wound, is linear at the outer side and convex at the inner side such that the curvatures 10 project into the interior of the guide element 4 and provide a smaller contact surface for the elongate strand material.

[0085] In the second variant (lower left representation), the flat wire coil spring is wound to have an approximate rectangular cross section, which lends particularly high stability to the coil spring.

[0086] In the third variant (upper right representation), the cross section of the wire exhibits concave curvatures 10 on the outer side and convex curvatures 10 on the inner side, all oriented toward the interior of the guide element 4.

[0087] In the fourth variant (lower right representation), the wire cross section is linear at the outer and inner side and exhibits convex curvatures 10 toward the front/rear on the front and rear side of the cross section when seen in the longitudinal direction of the guide element 4.

[0088] FIG. 5 constitutes a comparison of the power consumed by a bunching machine, wherein the machine is firstly equipped with a prior art rotor bow and then secondly with an inventive rotor bow provided with a spring coil as a guide element. The rotor bow from the prior art, on the other hand, comprises discrete guide elements which cover a groove in the body of the rotor bow at specific spacings, yet thereby protrude considerably beyond the cross section of the rotor bow body.

[0089] The same measured values are depicted in a table in FIG. 5a and as a bar chart in FIG. 5b.

[0090] To this end, the consumption values for various rotor bow twist rates (corresponding to double the respective number of revolutions in a double-twist bunching machine) of between 1000 and 6500 twists per minute (corresponding to 500 to 3250 revolutions) were measured. The power consumed in kW as well as the difference in performance values between the different rotor bows for the respective rotor bow at the respective number of twists is depicted in the three columns on the right in the table and by the three respective bars in the bar chart. One recognizes that particularly at high numbers of twists, a significant amount of power is saved with the rotor bow according to the invention.

LIST OF REFERENCE NUMERALS

[0091] 1 rotor bow [0092] 2 rotor bow body [0093] 3 groove [0094] 4 guide element [0095] 5 inlet-side removal area [0096] 6 deflection-side removal area [0097] 7 fixing device [0098] 8 fixing slot [0099] 9 fastening clip [0100] 10 wire curvature [0101] 11 pin-like tool