Joint for spokes of a spoked wheel and method for manufacturing such a joint

Abstract

The present application relates to a spoke joint for a spoke of a spoked wheel and to a method for manufacturing the joint, the joint comprising a stem having an axial extension, a threaded hole axially formed in the stem, the threaded portion of the hole being defined with a root diameter and a top diameter, a head portion widening with respect to the stem, and a deformable insert inserted into a seat axially aligned with the hole and configured in an axial intermediate position of the hole. The insert has a passage for a threaded spoke end portion, the internal diameter of the passage being less than the root diameter of the threaded portion of the hole at least when the insert is inserted into the seat, so that the passage interferes with the threaded portion of the spoke when the spoke is screwed into the threaded hole.

Description

Technical Field

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

[0002] Self-locking couplings are widely used in the construction of spoked wheels to prevent the couplings screwed onto the spokes from loosening without the use of thread-locking fluids or the like.

[0003] A self-locking joint, known and particularly popular in the field of bicycles and motorcycles, is described in US6205664 from the same applicant.

[0004] Other connectors of the same type are described in EP2525985, WO2004 / 065138 and WO2012 / 113599.

[0005] All of the above-described joints have a threaded axial seat. At one end of the threaded axial seat, typically in the head region of the joint, an insert made of deformable resin, usually polyamide resin, is applied. The insert is drilled to define a channel, the inner diameter of which is smaller than the top diameter of the threaded portion of the spoke. In this way, when the spoke is screwed into the joint, the spoke is inserted into the channel of the insert in an interference fit, simultaneously deforming the walls of the channel.

[0006] This interference creates the necessary lock between the spoke threads and the joint, thus preventing the spoke threads and joint from being accidentally loosened.

[0007] In all the above cases, the insert is applied to the axial end of the connector, which is typically the end furthest from the connector's own stem. This involves the spokes being long enough to reach the insert and be guided into its channel; otherwise, the self-locking effect of the connector will inevitably be unavailable.

[0008] To ensure this effect, it is necessary to construct the spokes to be not too long and, in particular, to machine the threaded ends on the larger portion, so that the threaded portion of the spokes can engage with the entire length of the threaded portion of the connector and be fully inserted into the channel of the insert made of resin.

[0009] Therefore, this technology requires a certain degree of waste of spoke material, resulting in a larger overall wheel weight, especially with a greater weight distribution at the far end of the spokes relative to the hub. This leads to undesirable inertial effects and greater energy consumption and tool wear for machining the spokes, which does not actually contribute to the wheel's mechanical resistance.

[0010] EP1559582A1 discloses a self-locking connector for bicycle wheel spokes, wherein an insert is applied to the axial center of the connector. However, it is evident that the process of axially inserting the insert into the connector presents significant difficulties due to the excessively large diameter of the insert relative to the threaded hole of the connector, especially considering that the insert material must provide a given resistance to deformation to ensure adequate engagement with the threaded portion of the spokes even after repeated tightening and loosening of the connector.

[0011] Instead, the desired solution is to provide a self-locking connector in which inserts can be applied quickly and accurately through a repeatable process.

[0012] Furthermore, it must be noted that the joint described in EP1559582A1 can only be manipulated by means of a tool extending axially from the head of the joint itself. Therefore, the joint cannot be manipulated without at least partially disassembling the wheel.

[0013] Instead, the desired solution is a self-locking joint that allows for adjustment of the tension of the corresponding spokes without having to remove the wheel. Summary of the Invention

[0014] The technical problem solved by the present invention is to provide a self-locking joint for spokes of a spoked wheel, which is structurally and functionally configured to at least partially overcome one or more of the disadvantages listed in the prior art as referenced herein.

[0015] This problem is solved by the splicing of the spokes for spoked wheels according to the present invention.

[0016] In one embodiment, the connector includes: a rod having an axially extended portion; a threaded hole axially formed in the rod, the threaded portion of the hole defining a root diameter and a top diameter; a head that widens relative to the rod; and a deformable insert inserted into a seat aligned axially with the hole, the insert having a channel for a threaded spoke end, the inner diameter of the channel being smaller than the root diameter of the threaded portion of the hole, at least when the insert is inserted into the seat, so that the channel interferes with the threaded portion of the spoke when the spoke is screwed into the threaded hole. Preferably, the seat is formed at a central position in the hole, and even more preferably, the seat is formed at a position spaced apart from the head, that is, between the head and an axially opposite opening of the threaded hole.

[0017] It can be pointed out that, in this context, the term “intermediate position” of a hole is preferably intended to be understood as the axial intermediate position of the hole.

[0018] In one embodiment of the invention, when the insert is inserted into the seat, the channel of the insert has an inner diameter that is approximately the same as the top diameter of the threaded portion of the hole, and the channel forms an interference fit with the threaded portion of the spoke.

[0019] Preferably, the seating portion for receiving the insert has a radial depth such that the insert is held axially within the seating portion.

[0020] Furthermore, it is preferable that the insert is radially retractable, particularly in an elastic manner, to allow the insert to be inserted from the outside into the corresponding seat through the axial hole of the connector.

[0021] This radial contractility is improved if the insert has a discontinuous cover and is preferably cylindrical, or even more preferably a cover that is interrupted in the circumferential direction by cuts to facilitate radial contraction of the insert. It can be noted that, in this context, the term "cover" is preferably intended to be understood as the wall of the insert and more specifically as the cylindrical wall of the insert.

[0022] Due to the discontinuity of the cover, the insert has a large radial shrinkage, which allows the insert itself to be easily and accurately axially inserted through the threaded hole of the connector in terms of depth. However, the aforementioned radial shrinkage does not presuppose that the insert is constructed of a particularly deformable material.

[0023] Therefore, due to the radially shrinkable nature provided by the discontinuity of the cover, the insert can also be constructed from a fairly tough material, such as nylon, which also has the advantage of withstanding repeated tightening and loosening of the spokes.

[0024] In one embodiment, the insert has a metal core that improves the elastic recovery of the insert after it has been inserted into the corresponding seat. Therefore, the metal core has the value of improving the accuracy and repeatability of the process of inserting the insert into the corresponding seat.

[0025] The core is preferably arranged circumferentially and is also interrupted at the cut of the cover.

[0026] The preferred materials for constructing the metal core of the insert are harmonic wire or spring steel.

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

[0028] A preferred method for manufacturing the connector according to the invention includes the following steps:

[0029] - Provide a semi-finished product, which is formed into a defined rod and a head that widens relative to the rod;

[0030] - Axial drilling is performed on the semi-finished product;

[0031] - A seat for a deformable insert is formed in the drilled axial hole, the seat being constructed in the middle position of the hole spaced apart from the head;

[0032] - Tap the axial hole;

[0033] - Insert the radially retractable insert into the seat. Attached Figure Description

[0034] The features and advantages of the invention will be better understood from the following detailed description of preferred but non-exclusive embodiments illustrated by way of non-limiting example with reference to the accompanying drawings, in which:

[0035] - Figure 1 This is a view of a portion of the spokes and the joint according to the invention, wherein the joint is shown in axial section;

[0036] - Figure 2 yes Figure 1 Exploded view of the connector;

[0037] - Figures 3 to 7 This is a schematic diagram of the connector in the aforementioned figure during different manufacturing steps of the connector. Detailed Implementation

[0038] In the accompanying drawings, a connector manufactured according to the invention is generally designated by 1. The connector 1 is intended to be applied to the threaded end 3 of the spoke 2 for constructing a spoked wheel (not shown).

[0039] The connector 1 includes a rod 4 and a head 5 that widens relative to the rod 4. Preferably, corresponding operating keys 6a and 6b are formed in the head and rod to rotate the connector 1 relative to the spokes for turning purposes. The first operating key 6a is preferably constructed in an axial recess of the head 5 (but can also be constructed, for example, by giving the head itself a polygonal shape), and the first operating key 6a can have different forms known per se, such as having a hexagonal insert, a Torqx-type profile, a Philips-type profile, a cut-out profile, etc. In this way, the connector can be operated by means of a tool extending from the first operating key 6a along the axis of the connector.

[0040] The second operating key 6b is preferably in the form of a polygonal recess (e.g., as shown in the image). Figure 2The square or hexagonal recess shown is constructed in the axial portion of the rod opposite to and at the distal end of the head 5. In this way, when the joint is mounted on the wheel, it remains accessible and operable, allowing the spoke tension to be adjusted by means of a tool extending from the second operating key 6b in a direction transverse to the axis of the joint without having to remove the wheel.

[0041] The connector also has a tapped axial hole 7, preferably a through hole (or alternatively a blind hole), which extends from the opening 9 to the distal end relative to the head 5, up to the seat of the first operating key 6a. The threaded portion of the hole 7 defines a root diameter D and a top diameter d.

[0042] The connector 1 is also provided with an insert 10, which is made of deformable resin, such as polyamide resin.

[0043] The insert 10 is preferably formed in a radially contractible cylindrical (annular) shape to allow for external mounting into a seat 11 formed in a hole 7, at an intermediate position between the head 5 and the opening 9. The seat 11 preferably has a shape with a cylindrical cover and a diameter 12, which is preferably larger than the top diameter d, and even more preferably, the diameter 12 is greater than or equal to the root diameter D of the threaded portion. In this way, the radial depth of the seat 11 allows the insert 10 to be axially held within the seat 11. The seat 11 also has an axial extension sufficient to receive and hold the insert 10.

[0044] To enable the insert 10 to retract radially, the insert 10 is configured to have a discontinuous cover, for example, by providing a cutout 13. Alternatively, the elasticity of the insert 10 itself or multiple local discontinuities in the cover of the insert 10 are used.

[0045] A channel 14 is defined in the insert 10, and at least when the insert 10 is inserted into the seat 11, the inner diameter of the channel 14 is smaller than the root diameter of the threaded portion of the hole 7, so that when the spoke 2 is screwed into the threaded hole 7, the channel 14 interferes with the threaded portion 3 of the spoke 2. This creates a self-locking connection between the spoke and the connector.

[0046] The seat 11 is preferably formed in the bore 7 in a position axially intermediate between the head 5 and the opening 9. This positioning allows for the use of shorter spokes than are required for known self-locking joints, ensuring optimal self-locking and proper sealing of the spoke / joint connection in all cases. To allow this connection, the seat 11 is spaced apart from the opening 9 of the joint by at least three or more threads.

[0047] In some embodiments, to promote the widening of the insert 10 after it is inserted into the seat 11, a metal core (not shown) is provided in the resin block. This metal core is made of, for example, harmonic wire and is preferably arranged circumferentially and embedded in the insert 10 at approximately the middle diameter. In this way, the insert 10 contracts radially due to its insertion into the seat 11, but when the insert 10 is released from the seat 11, the elastic recovery of the insert 10 and the metal core causes the insert 10 to expand radially.

[0048] The metal core is also interrupted at the cut 13 of the insert 10.

[0049] To construct the connector, a semi-finished product S obtained by molding from a pre-straightened and cut metal rod is used as the base component; the semi-finished product S is formed to define the external geometry of the connector, including a head 5, a rod 4 and corresponding operating keys 6a and 6b.

[0050] Therefore, axial drilling is performed on the semi-finished product S to obtain hole 7 and opening 9, as follows. Figure 3 As shown in the image.

[0051] Then, the machining of the seating part 11 is performed, such as... Figure 4 As shown in the figure, and tapping is performed on hole 7, as... Figure 5 As shown in the image.

[0052] Simultaneously, an insert in a radially contracted state is provided in the loading component C. The outer diameter of the insert is smaller than the top diameter d of the threaded portion of the hole 7, so that it can be introduced into the interior of the hole 7. Preferably, the insert is introduced into the interior of the hole 7 from the head 5 side until it is close to the seat 11, such as... Figure 6 As shown in the image.

[0053] To improve the accuracy and repeatability of the process of applying the insert 10 to the connector, it is preferable that the insert has a discontinuous cover (to improve the radial shrinkage of the insert when it is inserted into the loading member C) and a metal core (to improve the elastic recovery of the insert after it is inserted into the corresponding seat 11).

[0054] Therefore, the radially contracted insert is placed in the seat 11, in which the insert radially expands to regain the same outer diameter as the seat 11 itself, so as to keep it fitted in the seat between the shoulder formed by the end threaded portion of the hole 7 near the end threaded portion of the seat 11 itself.

[0055] Figure 7The connector 1 is shown as being prepared to receive the threaded end 3 of the spoke 2. When the connector is screwed onto the threaded end 3 of the spoke 2, the threaded portion of the spoke is screwed into the threaded portion of the connector until it reaches the insert 10.

[0056] The tightening action then continues in the channel 14 of the insert, causing the plastic material of the insert to deform due to the interference effect between the inner diameter of the insert and the threaded portion of the spoke. In extreme cases, the spoke length is sufficient to allow the spoke to be at least partially tightened into the insert 10 of the connector to achieve a self-locking connection. However, it is preferable to select the spoke length such that, in the case of wheel mounting, the connector is tightened onto the spoke, and the spoke engages with both threaded portions of the hole 7 separated by the seat 11.

[0057] Preferably, the loading member C is configured to accommodate a plurality of inserts 10, so that after the inserts 10 slide into the loading member C, one insert 10 is placed at a time in the corresponding seat 11 of the joint being processed by means of the force applied to the inserts 10 by means of the piston P.

[0058] Therefore, the present invention solves the proposed problem and achieves several advantages, including:

[0059] - Greater security, because a self-locking connection between the spokes and the joint is achieved even when the threaded end of the spoke does not reach the head of the joint.

[0060] - This can reduce the longitudinal extension of the spokes, thereby saving material and reducing the weight distribution of the spokes at the far end relative to the hub;

[0061] - The method for manufacturing connectors is simplified.

Claims

1. A spoke connector (1) for a spoked wheel, the connector (1) comprising: A rod (4) having an axially extended portion; a threaded hole (7) axially formed in the rod (4), the threaded portion of the hole (7) defining a root diameter (D) and a top diameter (d); a head (5) widening relative to the rod (4); and a deformable insert (10) inserted into a seat (11) axially aligned with the hole (7), the insert (10) having a channel (14) for the threaded spoke end, at least in the insert (10) being When inserted into the seat (11), the inner diameter of the channel (14) is smaller than the root diameter (D) of the threaded portion of the hole (7) so that when the spoke is screwed into the threaded hole (7), the channel (14) and the threaded portion of the spoke form an interference fit. The seat (11) is formed in the axial middle position of the hole (7), wherein the insert (10) is radially retractable, and the insert (10) has a discontinuous cover portion, wherein the insert (10) is made to be radially retractable due to the discontinuous cover portion.

2. The connector (1) according to claim 1, characterized in that, When the insert (10) is inserted into the seat (11), the channel (14) of the insert (10) has the same inner diameter as the top diameter (d) of the threaded portion of the hole (7), and the channel (14) forms an interference fit with the threaded portion of the spoke.

3. The connector (1) according to claim 1 or 2, characterized in that, The radial depth of the seat (11) for receiving the insert (10) is such that the insert (10) is held axially in the seat (11).

4. The connector (1) according to claim 1 or 2, characterized in that, The insert (10) is cylindrical and has a cover that is interrupted in the circumferential direction by a cut (13) to facilitate radial contraction of the insert (10).

5. The connector (1) according to claim 1 or 2, characterized in that, The insert (10) is constructed of plastic material.

6. The connector (1) according to claim 5, characterized in that, The insert (10) is made of nylon.

7. The connector (1) according to claim 1 or 2, characterized in that, The insert (10) has a metal core.

8. The connector (1) according to claim 4, characterized in that, The insert (10) has a metal core that is arranged circumferentially and is interrupted at the cut (13) of the cover.

9. The connector (1) according to claim 7, characterized in that, The core of the insert (10) is constructed of harmonic wire or spring steel.

10. The connector (1) according to claim 1 or 2, characterized in that, Corresponding operating keys are formed in the head (5) and the rod (4) to rotate the joint (1) relative to the spokes for the purpose of screwing.

11. The connector (1) according to claim 10, characterized in that, The first control key (6a) of the control keys is constructed in the axial recess of the head (5), or the first control key (6a) of the control keys is constructed by giving the head itself a polygonal shape.

12. The connector (1) according to claim 10, characterized in that, The second control key (6b) of the control keys is constructed in the form of a polygonal recess in the portion of the rod (4) that is axially opposite to the head (5) and located at the distal end.

13. The connector (1) according to claim 4, characterized in that, The cut (13) extends axially between opposite ends of the insert (10).

14. A method for manufacturing the connector (1) according to any one of claims 1 to 13, characterized in that, The method includes the following steps: - Provide a semi-finished product (S) which is formed to define an extension rod (4) and a head (5) that widens relative to the rod (4); - Axial drilling is performed on the semi-finished product (S); - Provides a radially retractable insert (10) having a discontinuous cover portion, wherein the insert (10) is made to be radially retractable due to the discontinuous cover portion; - A seat (11) for radially retractable insertion (10) is formed in the drilled axial hole (7), the seat (11) being constructed in the middle position of the hole (7) spaced apart from the head (5). - Tap the hole (7); - Insert the radially retractable insert (10) into the seat (11).

15. The method according to claim 14, characterized in that, The method includes: forming the semi-finished product (S) to define the external geometry of the connector (1), the connector (1) including the head (5), the rod (4) and a corresponding operating key, so as to rotate the connector (1) relative to the spokes for the purpose of twisting.

16. The method according to claim 15, characterized in that, The method includes: constructing the first control key (6a) of the control keys in the axial recess of the head (5), or constructing the first control key (6a) of the control keys by giving the head itself a polygonal shape.

17. The method according to claim 15, characterized in that, The method includes: a second control key (6b) of the control keys is constructed in the form of a polygonal recess in the portion of the rod (4) that is axially opposite to and distal to the head (5).

18. The method according to any one of claims 14 to 17, characterized in that, The method includes: providing a loading member (C) having an outer diameter smaller than the top diameter (d) of the threaded portion of the hole (7), and introducing the insert (10) in the loading member (C) in a radially contracted state into the interior of the hole (7) until it is close to the seat (11).

19. The method according to claim 18, characterized in that, The method includes: providing a piston (P) and configuring the loading member (C) to receive a plurality of inserts (10) so that, after the plurality of inserts (10) slide into the loading member (C), one insert (10) is placed at a time in a corresponding seat (11) of the joint being processed by means of a force applied to the insert (10) by means of the piston (P).

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