FR2767749A3 - Wheel spoke - Google Patents

Abstract

The wheel spoke, for a bicycle or moped and the like, has a flattened section (12) of part of its length with a cross section surface which is smaller than the cross section surface of the body (2) at one or both ends (3-5) of the spoke (1). The cross section surface of the flattened length (12) is at least 20% smaller than at the ends (3-5) of the spoke (1) or, even better, at least 40% smaller

Description

DESCRIPTION

  SPOKES, WHEELS THAT ARE PROVIDED WITH SPOKES OF THIS TYPE AND

  PROCESS FOR THE MANUFACTURE OF SUCH RADIUS

  The present invention relates to a spoke, more

specifically a wheel spoke.

  Firstly, it relates to a spoke which is intended for the wheels of bicycles, mopeds and the like; however, it is clear that this radius can also be

used in other wheels.

  More specifically, the invention relates to a spoke which is constituted by an oblong body which is provided at one end with a head for fixing the spoke to the hub of a wheel and which is provided at its other end with a screw thread for the application of a screw connection in order to

  fix the spoke near the rim of the wheel.

  Conventionally, the body of a spoke is produced by giving it a cross section of circular shape, the configuration being constant throughout

the length of the ray body.

  For some time now, it has also been known to flatten the body over most of its length, with the exception of the ends, so that a flattened cross section is obtained. Thus, we obtain the fact that, in any case, when the flattened cross-section is located in the correct direction, the air resistance to which the spoke is subjected during rotation of the wheel is reduced, which improves the aerodynamic behavior of the spoke. What has just been mentioned is especially of major importance in applications relating to racing bikes. Such a flattened radius also provides a particularly aesthetic effect. The flattened spokes known up to now are produced by bringing the round spokes into a press and by giving the part concerned, by means of a matrix, a more flattened shape such as for example a

ellipse, oval or the like.

  A major drawback associated with the flattened spokes known hitherto lies in the fact that they are not suitable for the usual hub openings. In order to be able to use these spokes despite everything, two recesses opposite one another are made in the hub openings, for example by means of a file, so that a passage is obtained for the flattened part. It is clear that this technique has the consequence of weakening the resistance of the flanges of the hub, that the application of recesses of this type is complicated and that no guarantee can no longer be

  supplied by the hub manufacturer.

  To reduce the resistance of the air undergone by a spoke and to be able nevertheless to fix this spoke in a conventional hub opening and by means of conventional screw fittings, it is also known to thin the spoke over part of its length. whether or not to keep the

rounded cross section.

  The subject of the present invention is a flattened spoke which is improved as regards the known embodiments, more specifically with regard to its aerodynamics and as to its resistance to fatigue, all of this by targeting a spoke which preferably

  corresponds to a normal hub opening.

  To this end, the invention relates to a spoke comprising a body which has a part which is flattened with respect to at least one end, more specifically with respect to the two ends of the spoke, characterized in that the area of the cross section of the flattened part is lower, more specifically considerably less than the area of a cross section taken through the body at the location of the corresponding end, respectively

from both ends of the spoke.

  By making a cross section whose area is smaller than the location of the flattened part, on the one hand, we keep the advantages linked to a flattened radius and, on the other hand, we also create the possibility

  to eliminate one or more of the aforementioned drawbacks.

  The inventor has also found that, by the combination of the above characteristics, more precisely on the one hand the fact that the radius is flattened and, on the other hand, the fact that the cross section of the flattened part has an area less than that of the cross section at the ends, we obtain a radius which manifests resistance considerably

  better at fatigue phenomena.

  In a preferred embodiment, the area of the cross section at the location of the flattened part will be at least 20% less than the area of the cross section at the location of the ends

  above, even better at least 40% lower.

  Particularly good results are obtained in the case where the cross-sectional area at the location of the flattened part represents less than half of the cross-sectional area at

  the location of the aforementioned ends.

  In the far preferred embodiment, the area of the cross section at the location of the flattened portion represents more than 40% of the area of the cross section at the location of the aforementioned ends, however less than 50%. Thus, an optimal compromise is obtained between, on the one hand, the resistance of the spoke and, on the other hand, other characteristics of the spoke, such as the aerodynamic resistance and the weight. In accordance with another preferred embodiment of the invention, the flattened part of the spoke represents a width which is less than or equal to the diameter of the conventional round opening made in the hub of the wheel for which this spoke is intended. Thus, we obtain the fact that, as already mentioned, we no longer have to make recesses in the circumference of the openings of the hub and, therefore, we

  no longer weakens the hub flanges.

  According to another preferred embodiment, the flattened part has a width which is less than or equal to 1.25 times the diameter measured at

  the location of the aforementioned ends.

  The invention also relates to a wheel, more specifically a bicycle wheel which is provided with

spokes according to the invention.

  Finally, the invention also relates to a method for producing spokes of this type, which is characterized by the fact that the flattened part is formed by thinning.

and flattening of the radius.

  In the far preferred embodiments of this method, thinning and flattening is accomplished by two separate treatments; preferably one proceeds first to thinning, then to flattening. In order to better indicate the characteristics according to the invention, a number of preferred embodiments are described below, by way of example, without any limiting character, with reference to the appended drawings in which: FIG. 1 represents a radius according to the invention; Figure 2 shows a view taken along arrow F2 in Figure 1; 3 shows a wheel in which spokes are inserted according to Figure 1; FIG. 4 represents a cross section on a larger scale of the part which is indicated in FIG. 3 by the arrow F4; Figure 5 shows, on a larger scale, a cross section taken along the line V-V in Figure 1; Figures 6, 7 and 8 show, on the same large scale, cross sections taken respectively along the lines VI-VI, VII-VII and VIII-VIII in Figure 2; FIG. 9 represents a variant of a spoke according to the invention in a view similar to that of FIG. 1; FIG. 10 schematically represents the method according to the invention; Figure 11 shows, on the same scale as that of Figures 5 to 8, a cross section taken along the line XI-XI in Figure 10; Figure 12 also shows a radius along

the invention.

  As shown in Figures 1 and 2, the invention relates to a spoke 1 which consists of an oblong body 2 which is provided at one end 3 with a head 4 and which

  is provided at its other end 5 with a screw thread 6.

  As is generally known and as shown in FIG. 3, spokes 1 of this type are used to form a connection, in a wheel 7, between the hub 8 and the rim 9. As shown in the enlargement of FIG. 4 , the spokes 1 are plugged in this case in openings 10 provided for this purpose in the hub 8 so that they come to be arranged with their

  head 4 behind the edge of the opening 10 in question.

  The spokes 1 are fixed to the rim 9 in a known manner by means of screw connections 11 which are screwed onto the

  ends 5 provided with a screw thread 6.

  As shown in Figures 1 and 2 and more specifically in the cross sections of Figures 8, the radius 1, in particular the body 2, has a flattened part 12 relative to the ends 3-5, which extends approximately over all the length of

body 2.

  The characteristic of the invention resides in the fact that the cross section of the flattened part 12 has an area S1 which is remarkably or considerably less than the area S2 of the

  cross section at the ends 3 and 5.

  As already mentioned in the introduction, the area S1 will preferably be at least 20% smaller than the area S2 and, even better, by 40%

lower.

  In the far preferred embodiment, the value of the area S1 itself will be less than half the value of the area S2. Thus, for example, in the case where the area S2 has a value of 11.34 mm2, the flattened part 12 will have a cross section whose area Sl has a

  value which is less than 5.67 mm2.

  Furthermore, it is preferable that the area Sl does not represent less than 40% of the area S2 in order to

  keep a radius 1 still sufficiently rigid.

  Preferably, the flattened part 12 also has a thickness T which is less than half the maximum diameter of the radius 1 at the location of the ends 3 and 5, in other words a thickness T which is less than half the diameter D indicated. More

  specifically, the thickness T will be approximately 1 mm.

  As shown in the figures, it is preferable that the flattened part 12 has a width B which is greater than or equal to the diameter D. More specifically,

  this width B will be equal to or less than 2.4 mm.

  Thus, in any case we obtain the possibility of easily inserting the spokes 1 through the hub openings 10 having a conventional dimension without having to widen these openings 10. Openings 10 of this type have, in the normal embodiments of the hubs, in any case of diameters Dl which are between 2.4 and

2.6 mm.

  It will be noted that the ends 3 and 5 of the radius 1, including the folded part 13, preferably have a circular cross section, as can be clearly seen in Figures 5, 6 and 8; however, it is not excluded to give another form to these ends. The particularity ensuring that the part 12 is flattened with respect to the ends 3-5 or with respect to at least one of these ends 3-5 means in any case that the thickness T is less than the smallest diameter of the radius at l location of the ends 3-5, measured in the same direction. By this is meant that the invention does not exclude the fact that the ends 3-5 are slightly flattened, while the part 12 is flattened to a greater extent. This flattening relates to the overall configuration of the corresponding cross-sections and not whether the sides of

  the flattened part 12 is curved or flat.

  In a normal embodiment, the diameter D will have a value of 2 to 2.2 mm. As shown in FIG. 7, the flattened part 12 will preferably have a cross section under

  the shape of an ellipse, an oval or the like.

  Other flattened configurations are not excluded, however. It is clear that the flattening of the part 12 takes place in a direction such that, in the mounted state of the radius 1, the longitudinal axis 14 is parallel or mainly

parallel to the plane of the wheel 7.

  Note that the invention can be applied to curved spokes as well as straight spokes. In figure 9,

  an example of the latter case is shown.

  The head 4 can also take a different shape, for example a spherical shape, as shown in FIG. 1, or a pyramidal shape, as shown in

figure 9.

  Preferably, the spokes 1 according to the invention are produced in accordance with the process which is shown

schematically in Figure 10.

  In this case, a steel wire 16 wound on a spool 15 is first guided through a device 17 in which the steel wire 16 is drawn in a straight line and thinned, respectively, over a determined length. As shown diagrammatically, this process is carried out by pulling the steel wire 6 using pliers 18 capable of reciprocating through clamping rollers 19, the latter being pressed each time over a defined distance from the travel of the steel wire 16. Next, the steel wire 16 is cut into pieces 21

in a cutting direction 20.

  It will be noted that these pieces 21 present at this moment, in their middle part, a thinned part 22 whose cross section is as shown in FIG. 11. Then, these pieces 21 are guided through devices 23 and 24 by which these pieces 21 of a head 4 and a screw thread 6, so that we

gets a radius.

  Only then does the radius thus flattened by compressing it flat in a press 25 on

a defined length.

  An important feature here is that the process itself first provides for

  thinning and only then a flattening.

  This technique offers the advantage that one can work with spokes made with materials

very hard.

  However, it is clear that, in a defined embodiment, the use of other devices by which the thinning and the flattening takes place, for example, is not excluded.

  simultaneous, for example using hammers.

  The present invention is in no way limited to the embodiments described above and shown in the drawings; a department of this type, as well as the aforementioned methods, can be implemented in accordance with different variants without departing from the scope of the invention. Thus it is not excluded, for example, to provide a flattened part 12 which has a cross-section with a smaller surface area only relative to one of the ends 3 or 5. This is for example the case when the end 3 is made with a cross section, as shown in Figures 5 and 6, when the flattened part is made with a cross section as shown in Figure 7 and when the end 5 is made with a

  cross section as shown in figure 11.

  It is not excluded either to provide for several parts

flattened on a single spoke.

  It will also be noted that the flattened part 12 does not necessarily have to be situated in a single plane, for example in a particular embodiment which is shown in FIG. 12, the flattened part 12 will be twisted, in other words twisted. Thus, not only is a particularly aesthetic effect created, but the radius 1 is also given greater rigidity. In a preferred embodiment of this feature, the overall diameter of the twisted or twisted part will be maintained at such a small point that this radius 1 can also be plugged into a conventional hub opening. The twisted part can extend as well over the entire length of the flattened part 12 as over a part of the latter. So,

  for example, the spoke could be twisted only at a single point, for example in the middle, for example on a half-twist. The twist can also be carried out with a different pitch.

Claims (17)

  1. A spoke comprising a body (2) which has a part (12) which is flattened with respect to at least one end, more specifically with respect to the two ends (3-5) of the spoke (1), characterized in that the area (Sl) of the cross section of the flattened part (12) is considerably less than the area (S2) of a cross section taken through the body (2) at the location of the corresponding end, respectively of the two ends (3-5) of the department (1).   2. Radius according to claim 1, characterized in that the area (S1) of the cross section at the location of the flattened part (12) is at least 20% less than the area (S2) of the cross section at the aforementioned ends (3-5),   even better at least 40% lower.   3. Radius according to claim 2, characterized in that the area (S1) of the cross section at the location of the flattened part (12) represents less than half of the area (S2) of the section   transverse to the aforementioned ends (3-5).   4. Department according to any one of the claims   above, characterized in that the area (S1) of the cross section at the location of the flattened part (12) represents at least 40% of the area (S2) of the cross section at the location of the ends cited above (3-5).   5. Department according to any one of the claims   above, by which this spoke (1) is provided, at one end (3), with a head (4) and by which this end (3) is intended to cooperate with a round opening (10) formed in a hub ( 8), and through which this opening (10) has a well defined diameter (D1), characterized in that the width (B) of the flattened part (12) is less than or equal to the diameter   (Dl) of the aforementioned round opening (10).   6. Department according to any one of the claims   previous, characterized in that the flattened part (12) has a thickness (T) which is less than half the diameter (D) measured at the ends cited above (3-5).   7. Department according to any one of the claims   previous, characterized in that the flattened part   (12) has a thickness (T) of about 1 mm.   8. Department according to any one of the claims   above, characterized in that the flattened part (12) has a width (B) which is greater than or equal to the diameter (D) measured at the ends cited above (3-5).   9. Department according to any one of the claims   above, characterized in that the flattened part (12) has a width (B) which is less than or equal to 2.4 mm.   10. Department according to any one of the claims   previous, characterized in that the ends (3-5) of the spoke (1) have cross sections of circular shape or of approximately circular shape.   11. Department according to any one of the claims   previous, characterized in that the flattened part (12) has a cross section in the form   an ellipse, an oval or the like.   12. Department according to any one of the claims   above, characterized in that the flattened part (12) has a width (B) which is less than or equal to 1.25 times the diameter (D) measured at the location of the aforementioned ends (3-5).   13. Department according to any one of the claims   previous, characterized in that the flattened part (12) is twisted over at least part of its length.   14. Wheel, more specifically bicycle wheel, characterized in that it is provided with spokes (1) such   as described in any one of claims 1 to 13.   15. Method for manufacturing a spoke such as   described in claims 1 to 13, characterized in   that form the flattened part (12) by thinning and flattening of the radius (1).   16. Method according to claim 15, characterized in that the thinning and the flattening is carried out means of separate treatments.   17. Method according to claim 16, characterized in that   that the flattening is carried out after the thinning.