High deformation and high retention ferrules
Patent Information
- Application Number
- JP2024527768
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2021-11-16
- Filing Date
- 2022-11-16
- Publication Date
- 2025-09-10
AI Technical Summary
Existing open ferrules are weaker in cable retention, more difficult to manufacture, and provide insufficient electrical shielding due to exposed cable braid, while closed ferrules are costly and harder to install.
A U-shaped ferrule design with varying cross-sections and plastic deformation to enhance cable retention and shielding, featuring a closed seam and chamfered edges for improved fit and stability.
The design provides enhanced cable retention, improved electrical shielding, and reduced risk of electrical shorts, while maintaining cost-effectiveness in manufacturing and assembly.
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Abstract
Description
[Technical field]
[0001] FIELD OF THE DISCLOSURE This disclosure relates to electrical ferrules, and more particularly to open crimpable ferrules.
[0002] Ferrules are commonly used to crimp cables into connectors. Closed-tube (i.e., seamless) ferrules typically provide much stronger cable retention and improved electrical performance than open-tube ferrules. However, closed-tube ferrules are much more expensive to manufacture and are more difficult to install and crimp onto a cable. Conversely, open or U-shaped ferrules are more efficient to manufacture and assemble onto a cable than tube-type ferrules, but generally provide weaker cable retention. Also, it can be more difficult to obtain adequate electrical shielding performance with open-tube ferrules because the cable braid is typically exposed in the open-tube ferrule design compared to closed-tube ferrules, which completely house or cover the cable braid along their length. Incomplete ferrule closure is also common along splice joints, especially due to poor springback resistance. The resulting exposed braid is a significant problem as it significantly increases the chance of electrical shorts.
[0003] Therefore, what is desired is an improved open crimpable ferrule that addresses these shortcomings while remaining cost-effective to manufacture and assemble.
[0004] In one embodiment of the disclosure, the cable assembly includes a conductive cable including an exposed conductive first portion having a first cross-section and a second portion adjacent the first portion having a second cross-section different from the first cross-section. The ferrule is disposed over the conductive cable and includes a body defining a joint formed axially through the ferrule. The ferrule further includes a first body portion deformed to a cross-section corresponding to the first portion of the conductive cable and a second body portion deformed to a cross-section corresponding to the second portion of the conductive cable.
[0005] The invention will now be described, by way of example only, with reference to the accompanying drawings, in which: [Brief description of the drawings]
[0006] [Figure 1] FIG. 2 is a perspective view of a ferrule in a crimped or closed state according to one embodiment of the present disclosure. [Diagram 2] FIG. 2 is a perspective view of the ferrule of FIG. 1 in a pre-crimped or open state. [Diagram 3] FIG. 3 is a front view of the ferrule of FIG. 2 in a pre-crimped or open state. [Figure 4] FIG. 2 is a top view of the ferrule of FIG. 1 crimped onto a cable assembly. [Diagram 5] FIG. 1 is a perspective view illustrating a bonded joint of a ferrule according to one embodiment of the present disclosure. [Figure 6] FIG. 1 is a perspective view of a ferrule in a pre-crimped or open state according to one embodiment of the present disclosure. [Figure 7] FIG. 7 is a perspective view of the ferrule of FIG. 6 in a crimped or closed state. [Figure 8] FIG. 1 is a perspective view of a ferrule in a pre-crimped or open state according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0007] The embodiments of the present disclosure include a U-shaped ferrule and a method of using the same. The ferrule is adapted to be crimped into an O-shaped ferrule, which has an overall diameter change in the form of a material plastic deformation that changes the overall diameter and thickness of the ferrule in at least one region along its axial length. In this manner, one portion of the ferrule can be formed to the shape of, for example, a cable jacket or other component of a cable assembly (e.g., a connector component), while another portion of the ferrule can be rigidly secured to the exposed inner braid or conductor of the cable. The deformation of the ferrule prevents springback of the closed end, improves retention and shielding properties, and minimizes the risk of other failures, such as electrical shorts.
[0008] FIG. 1 illustrates a ferrule 100 in a closed or crimped position or a crimped or crimped position according to one embodiment of the present disclosure. In the closed position, the body 105 of the ferrule 100 defines a generally hollow tapered cylindrical shape and / or a partially tapered hollow cylindrical shape. The body 105 is formed from respective first and second sidewalls 120 and 130 extending from a curved base 110. More specifically, through crimping, stamping, or other processing, the body 105 has been plastically deformed into the configuration of the drawings, with the base 110, sidewalls 120, and sidewalls 130 curved into the generally cylindrical shape shown. As a result, the free edges or ends 140 of the opposing sidewalls 120 and free edges or ends 142 of the sidewalls 130 abut continuously along the length of the ferrule 100 to define a closed or generally closed seam 150.
[0009] The exemplary body 105 defines a first portion 160 having a generally hollow cylindrical cross-section of a first inner diameter and / or a first outer diameter. The second portion 170 extends continuously from the first portion 160 and defines a tapered hollow cylindrical cross-section of a tapered or varying inner and / or outer diameter. The third portion 180 of the body 105 extends continuously from the second portion 170 and defines another hollow cylindrical cross-section of a second inner and / or outer diameter that is larger than the first diameter of the first portion 160. The first portion 160, the second portion 170, and the third portion 180 of the body 105 define a coaxial central opening 200 that extends longitudinally or axially of the ferrule 100 and / or its associated cable.
[0010] As body 105 deforms during crimping, first portion 160 is compressed radially inward under a force greater than the force on third portion 180. As a result, the material thickness T2 of the peripheral sidewall of first portion 160 increases, i.e., becomes greater than the thickness T1 of the remainder of body 105 (i.e., the original material thickness of the entire uncrimped ferrule or stock). Thus, the formation of portions 160, 170, and 180 not only involves a change in the outer dimensions (including length) of the ferrule, but also changes the in-plane thickness of the substrate of the first portion.
[0011] 2 and 3, the ferrule 100' is shown in an open state prior to crimping or other forming operations. As shown, the body 105 of the ferrule 100' has a generally U-shaped profile or cross-section defined by respective sidewalls 120, 130 extending diagonally outwardly from respective sides of a base 110. The cross-section of the body 105 is continuous and uniform along its axial length. More specifically, the axial length of the base 110 and the axial lengths of the walls 120, 130 are uniform or equal, as are the respective heights of the sidewalls 120, 130. The body 105 may be formed by processing a single sheet of conductive material, such as copper, of uniform thickness T1. Each of the edges or ends 140, 142 of the walls 120, 130 may define a first chamfer C running the longitudinal or axial length of each edge, and / or a chamfer C' formed transverse to the axial direction at each corner of the walls 120, 130. The chamfers C, C', specifically chamfer C, may aid in holding the abutting walls 120, 130 as shown in FIG. 1 and may resist opening or springback of the ferrule 100 after crimping or forming. In other embodiments, as shown in FIG. 8, the uncrimped ferrule 100" may comprise a non-uniform cross-section. More specifically, the ferrule 100" may be generally defined by two U-shaped sections 160, 180 of different sizes joined by a central tapered portion 170. As noted above, ferrule 100" has a uniform thickness T1 despite varying cross-section in the uncrimped state. Forming ferrule 100" with a non-uniform cross-section is advantageous in that it allows ferrule 100" to fit more tightly against the cable jacket and / or cable shield or conductors inside the cable prior to the crimping operation. The remaining features of ferrule 100" are common to uniform ferrule 100' and crimped ferrule 100 and therefore will not be described further.
[0012] 4, a closed ferrule 100 is shown for use in or as part of a cable assembly 50. The cable assembly 50 may include a cable 10 having at least one outer (or intermediate) jacket 15 and at least one inner conductor 20, such as a multi-stranded braided center conductor. As shown, the conductor 20 is exposed by removal of the jacket 15 in at least one area. In an exemplary embodiment, the cable 10 is inserted into an open ferrule (ferrule 100'), which is crimped (e.g., in a die) or otherwise plastically deformed to form a first portion 160, a second portion 170, and a third portion 180 of the body 105. As shown, at least the first portion 160 of the body 105 has an inner diameter corresponding to the outer diameter of the conductor 20 and is deformed to an exemplary thickness T2. In this manner, the ferrule 100 securely holds the conductor 20 and establishes reliable electrical contact therewith. Similarly, the ferrule 100 is held firmly in place by the third portion 180 of the body 110, which has an inner diameter corresponding to the outer diameter of the jacket 15. The stepped nature defined by the second portion 170 of the body 110 helps prevent axial translation of the ferrule 100 along the cable 10. Additionally, the deformation defined by the second portion 170 improves the resistance of the ferrule to opening or springing back to at least a partially open state after crimping. As shown, seam 150 is closed uniformly along the length of body 105. In other embodiments, third portion 180 may be used to attach to an interior portion (e.g., shield or conductor) of a cable having a larger diameter than the jacket of the cable coupled to first portion 160.
[0013] 5, in one embodiment of the present disclosure, the free edges 140, 142 of the body of the ferrule 100 may define mating or corresponding protrusions and recesses extending along the respective longitudinal lengths of the sidewalls of the ferrule 100. Specifically, the exemplary edge 140 may define a protruding lip 141 that extends circumferentially and into a corresponding recess 143 formed in the opposing sidewall edge 142. As shown, the protrusion or lip 141 and recess 143 both extend longitudinally through the length of the ferrule and are radially offset relative to one another. In this manner, the closed ferrule 100 may maintain a uniformly circular outer profile to maximize closure of the joint 150. This configuration may also improve the braid retention of the ferrule when used with stranded conductors.
[0014] It should be understood that ferrules according to embodiments of the present disclosure may be mated with other types of components having other shapes without departing from the scope of the present invention. For example, referring to the embodiment of Figures 6 and 7, another ferrule 300, 300' is shown. In the open state shown in Figure 6, the ferrule 300' comprises a U-shaped body 305 having a base 310 and two side walls 320, 330 similar to those described above with respect to the ferrules 100, 100'. However, in the exemplary embodiment, the ferrule 300' may be configured to secure a first end to a pair of electrical connectors or terminals, or to a single connector or terminal configured to hold two conductors. This may be accomplished by forming (e.g., stamping) a set of recesses or channels 360 in the base 310. In the exemplary illustrated embodiment, the channels 360 are formed such that there are axially extending arcuate ribs 362. The channels 360 extend axially into the base 310 to a depth D, which corresponds to, for example, the desired depth of a terminal or connector to be captured by the ferrule 300'.
[0015] In FIG. 7, the ferrule 300 is shown in a closed or crimped state. At a first end of the ferrule 300, the portion of the ferrule associated with the groove 360 extending to a depth D is plastically deformed to correspond in shape or cross section to an electrical terminal or connector 390 defined by at least two semicircular bodies. At the opposite or second end of the ferrule 300 (i.e., corresponding to the third portion 180 of the ferrule 100), the side walls 320, 330 are deformed to a corresponding generally cylindrical shape for securing a cable or cable jacket 380. The middle or central portion 370 of the ferrule 300 forms a continuous transition profile between the first and second ends. Despite the different cross sections of the first and second ends, the controlled crimping or deformation process keeps the seam 350 closed over the axial length of the ferrule 300, improving electrical shielding and the overall mechanical stability of the ferrule.
[0016] In view of the above embodiments, a method of forming a ferrule for use in a cable or cable assembly is also provided. The method includes the step of mounting a conductive cable to an uncrimped ferrule. As shown throughout the figures, the uncrimped ferrule has a generally uniform U-shaped cross-section. In one or more crimping steps, a first portion of the ferrule is crimped to a cross-section corresponding to a first cross-section of a first portion of the cable, and a second portion of the ferrule is crimped to a cross-section corresponding to a second cross-section of a second portion of the cable that is different from the first cross-section. Through either the crimping step or a separate closing step, opposing edges of the ferrule abut along the longitudinal or axial direction of the cable (or ferrule) to continuously close the ferrule around itself along its length.
Claims
1. A method of forming a ferrule (100, 300) for use in a cable assembly (50), comprising the steps of: crimping a first portion (160) of the ferrule (100) to a cross-section corresponding to a first cross-section of a first portion (20) of the cable assembly (50); crimping a second portion (180) of the ferrule (100) to a cross-section that is different from the first cross-section and corresponds to a second cross-section of the second portion (15) of the cable assembly (50); continuously closing the ferrule (100) around its circumference and along its length by abutting opposing edges (140, 142) of the ferrule along its length; A method comprising:
2. 2. The method of claim 1, wherein in an uncrimped state of the ferrule, the first portion and the second portion of the ferrule comprise a substantially uniform material thickness.
3. After the step of crimping the first portion (160) and the step of crimping the second portion (180), the thickness (T １ ) is the thickness (T ２ 3. The method of claim 2, wherein the .lambda.
4. The method of claim 3, wherein the uncrimped ferrule (100, 300) comprises a generally uniform U-shaped cross-section.
5. The method of claim 4 , wherein the first cross-section comprises a generally circular cross-section of a first diameter and the second cross-section comprises a generally circular cross-section of a second diameter greater than the first diameter.
6. The method of claim 3, further comprising the step of attaching a conductive cable (10) to the uncrimped ferrule (100, 300).
7. The method of claim 6, wherein the first portion of the conductive cable (10) comprises an exposed conductor (20).
8. The method of claim 7, wherein the second portion of the conductive cable (10) comprises a cable jacket (15).
9. 3. The method of claim 2, wherein the crimped ferrule (100, 300) is constructed from a single plastically deformed copper sheet.
10. 2. The method of claim 1, wherein the step of closing the ferrule (100, 300) around itself includes engaging a protrusion (141) with a corresponding recess (143) on each edge (140, 142) along the length of the ferrule (100, 300).
11. A conductive cable (10), a conductive first portion (20) having a first cross section; a second portion (15) having a second cross section different from the first cross section; a conductive cable (10) including: A ferrule (100) disposed over the conductive cable (10) and including a body (105), the body (105) comprising: a seam (150) formed axially through said body (105); a first body portion (160) formed with a cross section corresponding to the first portion (20) of the conductive cable (10); a second body portion (180) formed with a cross section corresponding to the second portion (15) of the conductive cable (10); A ferrule (100) defining A cable assembly (50) comprising:
12. 12. The cable assembly (50) of claim 11, wherein the joint (150) is defined by continuously abutting free edges (140, 142) of annular walls (120, 130) of the body (105) to continuously close the ferrule (100) around itself along its axial length.
13. 13. The cable assembly (50) of claim 12, wherein the abutting free edges (140, 142) of the body (105) define opposing protrusions (141) and recesses (143) extending along the axial length of the body (105), and each protrusion (141) is inserted into each corresponding recess (143) by the ferrule (100).
14. 12. The cable assembly (50) of claim 11, wherein the first cross-section comprises a generally circular cross-section of a first diameter and the second cross-section comprises a generally circular cross-section of a second diameter greater than the first diameter.
15. 12. The cable assembly (50) of claim 11, wherein the third body portion (170) of the ferrule (100) includes an annular profile that tapers between the first body portion (160) and the second body portion (180).