Self-locking nipple for spokes of a spoked wheel and method for manufacturing such a nipple

Abstract

A nipple for a spoke of a spoked wheel includes an axially extending rod having an axially threaded bore formed therein. The threads of the threaded bore define a root diameter and a crest diameter. The nipple further includes a head that is wider relative to the rod and a deformable insert that is inserted into a seat that is axially aligned with the threaded bore. The insert has a passage for the threaded spoke end, at least when inserted into the seat. The inner diameter of the passage is smaller than the root diameter of the threads of the threaded bore so that an interference fit is formed between the spoke and the threads when the spoke is threaded into the threaded bore.

Description

[Technical Field]

[0001] The present invention relates to a self-locking nipple for the spokes of a spoked wheel and to a method for manufacturing such a nipple. [Background technology]

[0002] Self-locking nipples are widely used in spoke wheel construction to prevent loosening of nipples that thread onto the spokes without the use of thread locking agents or the like.

[0003] The same applicant's US Pat. No. 6,205,664 describes a self-locking nipple which is known and particularly appreciated in the field of bicycles and motorcycles.

[0004] Other nipples of the same type are described in EP 2525985, WO 2004 / 065138 and WO 2012 / 113599.

[0005] All of the nipples mentioned above have an axial threaded seat, to one end of which, generally in the region of the nipple's head, an insert is applied, generally made of a deformable resin such as polyamide resin. This insert is drilled to define a passage, the inside diameter of which is smaller than the crest diameter of the spoke threads. Thus, when the spoke is screwed into the nipple, it is inserted therein with an interference fit, deforming the walls of the passage in the insert.

[0006] The interference allows for the desired locking between the spoke threads and the nipple, preventing unintentional unthreading.

[0007] In all the above cases, the insert is applied to the axial end of the nipple, generally the end of the nipple itself furthest from the rod. For this reason, the spoke must be long enough to reach the insert and be introduced into its passage. If it is not long enough, the self-locking effect of the nipple will inevitably not be achieved.

[0008] To achieve this reliably, the spokes must be constructed to be significantly longer, and in particular, machined over a large portion of the threaded end so that the spoke threads engage the entire length of the nipple threads and are fully inserted into the passage of the plastic insert.

[0009] This technique therefore wastes some spoke material and increases the overall weight of the wheel, especially the weight distributed at the distal ends of the spokes relative to the hub, resulting in undesirable inertial effects and energy consumption and wear on the tools used to process spoke parts that do not actually contribute to the mechanical resistance of the wheel.

[0010] European Patent Application No. 1559582A1 describes a self-locking nipple for bicycle wheel spokes. An insert is applied to the nipple at an axially intermediate position. However, the insert's dimensions are too large relative to the diameter of the nipple's threaded hole, making the axial insertion process of the insert into the nipple substantially difficult. This is particularly difficult considering that the insert's material must provide a certain resistance to deformation to ensure proper engagement with the spoke threads after repeated screwing and unscrewing operations.

[0011] It would be desirable to provide a self-locking nipple that allows for fast and accurate application of an insert in a repeatable process.

[0012] It should further be noted that the nipple described in EP 1 559 582 A1 can only be operated by an instrument extending axially from the head of the nipple itself, and therefore cannot be operated without at least partial disassembly of the wheel.

[0013] It would be desirable to provide a self-locking nipple that allows adjustment of the tension in each spoke without disassembling the wheel. Summary of the Invention [Problem to be solved by the invention]

[0014] The technical problem addressed by the present invention is to provide a self-locking nipple for spokes of a spoked wheel that is structurally and functionally configured to at least partially overcome one or more of the drawbacks presented with reference to the cited prior art. [Means for solving the problem]

[0015] This problem is solved by the present invention, which comprises a nipple for a spoke of a spoked wheel, which comprises one or more of the features set out in the accompanying claims.

[0016] In one embodiment, the nipple includes an axially extending rod having an axially threaded bore formed therein. The threads of the bore define a root diameter and a crest diameter. The nipple also includes a head that is wider relative to the rod and a deformable insert that is inserted into a seat that is axially aligned with the bore. The insert has a passage for the threaded spoke end, at least when inserted into the seat. The insert has an inner diameter that is smaller than the root diameter of the threads of the bore so that an interference fit is formed between the spoke threads when the spoke is threaded into the bore. Preferably, the seat is formed at an intermediate location of the bore, more preferably at a location spaced from the head, i.e., between the head and an axially opposite opening of the bore.

[0017] It should be noted that in this specification, the term "intermediate position" of the screw hole is intended to preferably mean the axially intermediate position of the screw hole.

[0018] In one embodiment of the present invention, when the insert is inserted into the seat, the insert passage has an inner diameter approximately the same as the crest diameter of the threads of the threaded hole, so as to create an interference fit with the spoke threads.

[0019] Preferably, the seat that receives the insert has a radial depth such that the insert is axially retained within the seat.

[0020] Preferably, the inserts are also radially contractible, in particular elastic, so that they can be inserted into the respective seats from the outside via the axially threaded holes in the nipples.

[0021] This radial shrinkage is improved when the insert has a discontinuous outer shell, preferably cylindrical, and more preferably interrupted circumferentially by cutouts to facilitate radial shrinkage thereof. Note that, in this specification, the term "shell" is intended to refer to the wall of the insert, and more particularly, to the cylindrical wall of the insert.

[0022] As a result of the discontinuity in the outer shell, the insert can have a large radial contraction, which allows it to be easily and accurately inserted deep axially through the threaded hole of the nipple, although this radial contraction does not require the insert to be made of a particularly soft material.

[0023] The discontinuity in the outer shell provides radial contraction, allowing the insert to be constructed from a relatively stiff material, such as nylon, which has the advantage of being able to withstand repeated screwing and unscrewing of the spokes.

[0024] In one embodiment, the inserts have a metal core that can improve their spring back after being inserted into their respective seats, which has the advantage of improving the accuracy and repeatability of the process of inserting the inserts into their respective seats.

[0025] Preferably, the cores are circumferentially arranged and interrupted by cutouts in the shell.

[0026] Preferred materials for constructing the metal core of the insert include harmonic wire or spring steel.

[0027] Advantageously, the insert is made of a plastic material, preferably nylon.

[0028] A preferred method for manufacturing a nipple according to the present invention comprises: providing a workpiece formed to define a rod and a head that is wider than the rod; Axial drilling of the semi-finished product; forming a seat for the deformable insert within the formed axial bore at an intermediate position of the bore and spaced from the head; Tapping the axial hole; Inserting a radially shrinkable insert into the seat; Includes. [Brief explanation of the drawings]

[0029] The features and advantages of the present invention will become more apparent from the following detailed description of preferred and non-limiting embodiments, given by way of non-limiting example with reference to the accompanying drawings. [Figure 1] 1 is a view showing a portion of a nipple and spokes according to the present invention, the nipple being shown in axial cross section; [Figure 2] FIG. 2 is an exploded view of the nipple shown in FIG. [Figure 3] 3A to 3C are schematic diagrams showing manufacturing steps for the nipple shown in FIGS. 1 and 2. [Figure 4] 4 is a schematic diagram showing a manufacturing step different from that shown in FIG. 3 for the nipple shown in FIG. 1 and FIG. 2. [Figure 5] 5 is a schematic diagram showing a manufacturing step different from that shown in FIGS. 3 and 4 for the nipple shown in FIGS. 1 and 2. FIG. [Figure 6] 6 is a schematic diagram showing a manufacturing step different from that shown in FIGS. 3 to 5 for the nipple shown in FIGS. 1 and 2. FIG. [Figure 7] 1 and 2. FIG. 7 is a schematic diagram showing a manufacturing step different from that shown in FIGS. DETAILED DESCRIPTION OF THE INVENTION

[0030] In the figures, a nipple made in accordance with the invention is generally designated by the reference number 1. The nipple 1 is intended to be applied to the threaded ends 3 of spokes 2 to form a spoked wheel (not shown).

[0031] The nipple 1 comprises a rod 4 and a head 5 which is wider relative to the rod 4. Preferably, the head and rod are formed with operating keys 6a and 6b, respectively, for rotating the nipple 1 relative to the spoke for screwing. Preferably, the first operating key 6a is formed in an axial recess of the head 5 (although the head itself may be configured to have a polygonal shape, for example) and may have different known forms, such as a hex socket, a torx profile, a cross-shaped profile, or a notched profile. In this way, the nipple can be operated by an instrument extending from the first operating key 6a along the axis of the nipple.

[0032] Preferably, the second operating key 6b is configured in the form of a polygonal recess (for example a square recess as shown in FIG. 2, or a hexagonal recess) in the part of the rod axially opposite and distal to the head 5. In this way, when the nipple is mounted on the wheel to allow adjustment of the spoke tension, the nipple remains accessible and operable by an instrument extending from the second operating key 6b transversely to the axis of the nipple, without disassembling the wheel.

[0033] The nipple further has a tapped, axially threaded bore 7, which is preferably a through bore (or alternatively a blind bore) and extends from the opening 9 distally relative to the head 5 to the seat of the first operating key 6a. The threads of the threaded bore 7 define a root diameter D and a crest diameter d.

[0034] Furthermore, the nipple 1 is provided with an insert 10 made of a deformable resin, for example a polyamide resin.

[0035] Preferably, the insert 10 is formed to have a cylindrical, tubular (annular) shape. It contracts radially so as to fit from the outside into a seat 11 formed in the bore 7 at a position intermediate the head 5 and the opening 9. Preferably, the seat 11 has a cylindrical shell shape and a diameter 12 that is preferably greater than the crest diameter d of the threads, and more preferably greater than or equal to the root diameter D of the threads. Thus, the radial depth of the seat 11 is such that the insert 10 is axially retained in the seat 11. Furthermore, the seat 11 has a sufficient axial extent to receive and retain the insert 10.

[0036] To allow the insert 10 to contract radially, the insert 10 can be configured to have a discontinuous outer shell, for example, by providing cutouts 13. Alternatively, the elasticity of the insert 10 itself or multiple partial discontinuities in its outer shell can be utilized.

[0037] A passage 14 is defined within the insert 10. The inner diameter of the passage 14 is smaller than the root diameter of the threads of the threaded hole 7 so that when the passage 14 is inserted into at least the seat 11 and the spoke 2 is threaded into the threaded hole 7, an interference fit is formed between the passage 14 and the threads 3 of the spoke 2, thereby creating a self-locking connection between the spoke and the nipple.

[0038] Preferably, the seat 11 is formed in the hole 7 axially midway between the head 5 and the opening 9. This arrangement allows the use of shorter spokes than those required with conventional self-locking nipples, while ensuring optimal self-locking function and a proper seal at the spoke-to-nipple connection. To allow for this connection, the seat 11 is positioned at least three or more threads away from the nipple opening 9.

[0039] In some embodiments, a metal core (not shown), such as a steel piano wire, is provided within the resin mass to facilitate expansion of the insert 10 after it has been inserted into the seat 11. This is preferably circumferentially disposed and embedded in the insert 10 at approximately its mid-diameter. In this way, the insert 10 contracts radially when inserted into the seat 11, and is urged to expand radially by both its own resilience and that of the metal core when released from the seat 11.

[0040] The metal core is also terminated at the cutout 13 of the insert.

[0041] To construct the nipple, a semi-finished product S obtained by molding from a previously straightened and cut metal rod is used as a basis. The semi-finished product S is formed to define the outer shape of the nipple, including the head 5, the rod 4 and the respective operating keys 6a and 6b.

[0042] The semi-finished product S is also axially drilled to provide holes 7 and openings 9, as shown in FIG.

[0043] Thereafter, the seat 11 is machined as shown in FIG. 4, and the hole 7 is tapped as shown in FIG.

[0044] 6, the insert is mounted in the loader C in a radially contracted state. The outer diameter of the loader C is smaller than the crest diameter d of the thread of the screw hole 7, which allows the insert to be introduced into the hole 7 preferably from the head 5 side to a position near the seat 11.

[0045] Preferably, to increase the accuracy and repeatability of the application process of the insert 10 in the nipple, the insert has a discontinuous outer shell (to improve radial contraction of the insert when inserted into the loader C) and a metal core (to improve elastic return of the insert after insertion into the respective seat 11).

[0046] In this way, the radially contracted insert is placed in the seat 11, where it expands radially, regaining an outer diameter equal to that of the seat 11 itself, and remains embedded in the seat between the shoulders formed by the end threads of the hole 7 in the vicinity of the seat 11 itself.

[0047] Figure 7 shows a nipple 1 ready to receive the threaded end 3 of a spoke 2. When the nipple is screwed onto the threaded end 3 of the spoke 2, the threads of the spoke are threaded into the threads of the nipple until they reach the insert 10.

[0048] The screwing action then continues in the insert's passage 14, deforming the insert's plastic material as a result of the interference effect between the insert's inner diameter and the spoke's threads. At the limit, the spoke's length is sufficient to allow it to be at least partially threaded into the nipple's insert 10 in order to obtain a self-locking connection. However, the spoke's length is preferably selected so that, with the wheel mounted, the nipple is threaded onto the spoke with engagement of both threads of the hole 7 remote from the seat 11.

[0049] Preferably, the loader C is configured to include a plurality of inserts 10, so that the inserts 10 can be placed one by one in the respective seats 11 of the nipple being processed after sliding into the loader C via the force exerted by the piston P.

[0050] Thus, the present invention solves the above-mentioned problems and achieves many of the following advantages: If the threaded end of the spoke does not reach the head of the nipple, a self-locking connection is obtained between the spoke and the nipple, which is safer. Reducing the longitudinal length of the spokes saves material and reduces the weight distributed to the distal ends of the spokes relative to the hub. The manufacturing method of the nipple can be simplified.

Claims

1. A nipple (1) for a spoke of a spoked wheel, The nipple (1) comprises an axially extending rod (4), A screw hole (7) is formed in the rod (4) in the axial direction. the threads of said threaded hole (7) define a root diameter (D) and a crest diameter (d); The nipple (1) further comprises a head (5) that is widened relative to the rod (4) and a deformable insert (10) inserted into a seat (11) that is axially aligned with the threaded hole (7), The insert (10) has passages (14) for threaded spoke ends, at least when inserted into the seat (11), The inner diameter of the passage (14) is smaller than the root diameter (D) of the thread of the screw hole (7) so that an interference is formed between the spoke and the thread of the screw hole (7) when the spoke is screwed into the screw hole (7); The seat portion (11) is formed at an axially intermediate position of the screw hole (7), The insert (10) has a radially shrinkable, discontinuous outer shell; The insert (10) is radially contractible due to the discontinuous outer shell. Nipple (1).

2. 2. A nipple (1) according to claim 1, wherein when the insert (10) is inserted into the seat (11), the passage (14) of the insert (10) has an inner diameter substantially the same as the crest diameter (d) of the threads of the screw hole (7) so as to form an interference fit with the threads of the spoke.

3. 3. A nipple (1) according to claim 1 or 2, wherein the seat (11) receiving the insert (10) has a radial depth such that the insert (10) is axially retained within the seat (11).

4. A nipple (1) according to any one of claims 1 to 3, wherein the insert (10) is cylindrical and has an outer shell interrupted circumferentially by cutouts (13) to facilitate its radial contraction.

5. Nipple (1) according to any one of claims 1 to 4, wherein the insert (10) is made of a plastic material.

6. 6. The nipple (1) according to claim 5, wherein the insert (10) is made of nylon.

7. 5. The nipple (1) according to claim 4, wherein the insert (10) has a metal core.

8. 8. The nipple (1) according to claim 7, wherein the metal core is arranged circumferentially and is interrupted at the cutouts (13) in the outer shell.

9. A nipple (1) according to claim 7 or 8, wherein the metal core of the insert (10) is made of piano wire or spring steel.

10. A nipple (1) according to any one of claims 1 to 9, wherein the head (5) and the rod (4) are respectively formed with a first operating key (6a) and a second operating key (6b) for rotating the nipple (1) relative to the spoke for screwing.

11. 11. Nipple (1) according to claim 10, characterized in that the first operating key (6a) is formed in an axial recess of the head (5) or is constituted by giving the head a polygonal shape.

12. 12. The nipple (1) according to claim 10 or 11, wherein the second operating key (6b) is configured in the form of a polygonal recess in the part of the rod (4) axially opposite and distal to the head (5).

13. A nipple (1) according to any one of claims 5 to 12 when dependent on claim 4, wherein the cutout portion (13) extends axially between both end portions of the insert (10).

14. A method for manufacturing a nipple (1) according to any one of claims 1 to 13, comprising the steps of: providing a semi-finished product (S) formed to define a rod (4) and a head (5) that is wider relative to said rod (4); A step of drilling holes in the semi-finished product (S) in the axial direction; providing a radially shrinkable insert (10) having a discontinuous outer shell and being radially shrinkable by said discontinuous outer shell; forming a radially contractible seat (11) for said insert (10) in the formed axial bore (7) at a position spaced from said head (5) and intermediate said bore (7); tapping the hole (7); Inserting the radially contractible insert (10) into the seat (11); A method comprising:

15. 15. The method according to claim 14, further comprising forming the semi-finished product (S) to define an outer shape of the nipple (1) including the head (5), the rod (4), and a first operating key (6a) and a second operating key (6b) provided on the head (5) and the rod (4), respectively, for rotating the nipple (1) relative to the spoke for threading.

16. 16. The method according to claim 15, further comprising forming the first operating key (6a) in an axial recess of the head (5) or forming the first operating key (6a) by giving the head a polygonal shape.

17. 17. The method according to claim 15 or 16, further comprising forming the second operating key (6b) in the form of a polygonal recess in a portion of the rod (4) axially opposite and distal to the head (5).

18. The method according to any one of claims 14 to 17, further comprising the steps of: providing a loader (C) having an outer diameter smaller than a crest diameter (d) of the thread of the hole (7); and introducing the insert (10) in a radially contracted state into the loader (C) in the hole (7) to a position adjacent to the seat (11).

19. 19. The method according to claim 18, comprising the steps of providing a piston (P) and configuring the loader (C) to include a plurality of the inserts (10), wherein the plurality of inserts (10) are disposed one by one in the seats (11) of each of the nipples being processed after sliding into the loader (C) via a force exerted by the piston (P).

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