Cable connector stress release system

Abstract

The cable connector includes a housing. The housing has a cable opening for receiving a cable through the cable opening, the cable having a plurality of wires. The terminal insert is connected to the housing at an insertion side of the housing. A plurality of terminals are disposed within the terminal insert, each of the terminals being connected to a respective conductor within one of the plurality of wires. A stress relief element is arranged within the housing and is designed to transfer a force into the housing. The stress relief element includes a plurality of through openings for the electrical wires. A plurality of wire sleeves are disposed within the housing, one of the wire sleeves each securely connected to one of the wires in an exposed wire section of the cable between the stress relief element and the terminal insert.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 435,109, filed on December 23, 2022, the content of which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates to a stress - relief system for cable connectors. Background Art

[0004] Cable connectors must meet the requirements of an industry with ever - increasing demands. For example, certain connectors must comply with the UL1682 standard. This standard applies to pin - and - sleeve - type plugs, receptacles, power inlets, and connectors with a rated current up to 800A and a rated voltage up to 600V, and the devices may include up to eight pilot contacts. These devices are intended to supply power from a branch circuit or to be directly connected to a branch circuit using copper conductors for use in indoor or outdoor non - hazardous locations.

[0005] Connectors may also have to comply with the UL 2875 standard. This standard covers modular multi - pole connectors for use with specific - identified cable types and forms the following modular cable system when assembled: The modular cable system consists of a cable, a field - installed or factory - assembled modular multi - pole connector, and other associated system devices. These modular cable systems are intended for installation within commercial and industrial locations, such as, for example, within material handling distribution systems and wind turbine towers.

[0006] The UL1682 standard and the UL 2875 standard require that connectors meet the cable safety, i.e., the "pull - test" requirements. For example, the cable safety test requires that connectors with a rated electrical load between 36A and 200A withstand a 667N pull on the cable in the connector for 60 seconds, thereby limiting the allowable axial displacement of the supply conductor, conductor insulator, or outer sheath of the cable to 2.4mm. Large connectors have met this requirement, but the industry demands that smaller connectors meet the same requirement. Summary of the Invention

[0007] A stress relief mechanism for a cable connector typically absorbs the tensile force acting on the cable into the connector housing. This prevents unwanted movement of the wires and terminals. For example, these wires and terminals carry an electrical load of up to 200 A. One method is to provide stress relief by clamping the cable and compressing the outer sheath of the cable with a clamping grommet. Then, the tensile force acting on the cable is transferred to the connector housing through friction from the clamping grommet. However, clamping of the cable outer sheath has several disadvantages. For example, compression of the wires inside the cable may cause a change in wire resistance and result in hot spots. The clamping grommet may severely deform the cable and cause damage to the outer sheath.

[0008] The present disclosure provides improved stress relief that does not rely on clamping the outer sheath of the cable. Instead, one or more wires within the cable are fixed to prevent stress. The wires can be fixed individually, or in groups of two or more wires.

[0009] In one example, a cable connector includes a housing. The housing has a cable opening for receiving a cable passing through the cable opening, the cable having a plurality of wires. A plurality of terminals are arranged within a terminal insert, each of the terminals being connected to a corresponding conductor within one of the plurality of wires. A stress relief element includes a plurality of through openings. A plurality of wire sleeves are connected to the wires, each of the wire sleeves being securely connected to one of the wires in an exposed wire section of the cable between the stress relief element and the terminal insert. The stress relief element can be in the shape of a plate.

[0010] Each of the through openings has a width and a length. The outer diameter of the wire sleeve exceeds the width of the corresponding through opening. However, the outer diameter of the wire sleeve can be shorter than the length of the corresponding through opening. The through opening can include a semi-circular portion, the diameter of which corresponds to the diameter of the wire.

[0011] An outer portion of the stress relief element is supported within the housing, for example, on a flange provided within the housing. When in use, the wire sleeve transfers the tensile force acting on the wire through the cable into the stress relief element. In turn, the stress relief element transfers the tensile force into the housing.

[0012] The stress relief element may include two through openings that are connected by a connecting groove. An access groove may extend from the side of the stress relief element to the connecting groove. In one particular example, the stress relief element may include: two pairs of connected through openings that can be accessed from the side of the stress relief element through the engaging access grooves; and a single through opening that can be accessed from the side of the stress relief element through a separate access groove. The stress relief element may also include a spacer that extends forward from the center of the stress relief element.

[0013] In another example, the stress relief element may include a circular through opening that is centrally disposed between four stadium-shaped through openings.

[0014] The wire sleeve is preferably substantially composed of polyolefin, i.e., a heat-shrinkable material. A heat-melt adhesive layer may be disposed between the wire sleeve and the wire.

[0015] In another example, the stress relief element may include a single through opening. A single wire may extend through the single through opening and be fixed to prevent being pulled back through a single wire sleeve.

[0016] Multiple wires may also extend through a through opening and be held together jointly and fixed to prevent being pulled back through a wire sleeve.

[0017] A method for installing the disclosed cable connector to a cable includes several steps, and the several steps include:

[0018] Inserting the cable through the cable opening of the housing;

[0019] Arranging the wires of the cable to extend through the through openings of the stress relief element;

[0020] Sliding a plurality of wire sleeves onto the wires, with each of the wire sleeves in the cable's exposed wire section being placed on one or more of the wires in the cable;

[0021] Applying heat to the wire sleeves, thereby causing the wire sleeves to shrink and firmly connect to the wires;

[0022] Inserting the terminals of each wire into the terminal insert; and

[0023] Connecting the terminal insert to the housing.

[0024] These steps can be performed in any technically feasible order. For example, applying heat to the wire sleeve can be performed after arranging the wires of the cable to extend through the through-opening of the stress relief element. This allows the wires and the attached terminals to be routed through the through-opening of the stress relief element. Alternatively, arranging the wires of the cable to extend through the through-opening of the stress relief element can include laterally threading one of the wires into a slot and sliding it into one of the through-openings. Then, the wire sleeve can be secured to the wire even before the wire is inserted into the stress relief element.

[0025] Applying heat to the wire sleeve can include: melting an adhesive lining on the interior of the wire sleeve; and forming an adhesive bond between the wire sleeve and the wire.

[0026] The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Further, there is no intention to be bound by any theory presented in the foregoing background or the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a perspective front and side view of a cable connector.

[0028] Figure 2 is as Figure 1 in the perspective front and side view of the connector in which the connector housing is removed to show the interior of the cable connector.

[0029] Figure 3 is as in Figure 1 a detailed perspective rear view of the stress relief element used in the connector shown.

[0030] Figure 4 is a schematic view of a cable end.

[0031] Figure 5 is as Figure 1 in the perspective cross-sectional top view of the connector.

[0032] Figure 6 is a perspective side view of a second cable connector.

[0033] Figure 7 is as Figure 6 in the perspective rear and side cross-sectional view through the second connector.

[0034] Figure 8 is as in Figure 6 a detailed view of the stress relief element and wire sleeve used in the second connector shown. DETAILED DESCRIPTION

[0035] Figure 1The cable connector 1 is shown. The connector 1 includes a housing 10. A terminal insert 30 extends outward from the insertion side at the front of the housing 10. A cable grommet 20 is screwed into the rearward cable opening of the housing 10 on the cable outlet side of the connector 1.

[0036] Figure 2 The cable connector 1 as shown without the housing 10 Figure 1 is shown. Inside the housing 10, the terminal insert 30 is held within a frame 60. The frame 60 is fixed to the housing 10 by a snap lock 61.

[0037] A stress relief element in the form of a stress relief plate 40 is also arranged within the housing 10. In front of the stress relief plate 40, i.e., on the insertion side of the stress relief plate 40, there are a plurality of wire sleeves 50. During assembly, the wire sleeves 50 are firmly connected to the respective wires 74 of the cable 70.

[0038] Figure 4 The anatomy of the cable 70 is schematically illustrated. A plurality of wires 74 for carrying current are arranged within the cable 70. Each of the wires includes a conductor 73 within a wire insulator 72. The wires 74 are arranged within an outer sheath 71. For installation within the cable connector, the outer sheath 71 is stripped from the cable 70 to form an exposed wire section 75. The exposed wire section is arranged within the housing 10 on the insertion side of the cable grommet 20. Within the exposed conductor section 76 of the wire 74, the respective conductor 73 is connected to a terminal 31. Cable connector terminals are typically male but can also be female. The terminals can be of the screw terminal type, the crimp terminal type, or the cage clamp terminal type.

[0039] Figure 4 A single wire sleeve 50 attached to one of the three wires 74 is shown. In practice, more than one and preferably all of the wires 74 are fitted with respective wire sleeves 50. Alternatively, one wire sleeve 50 can be used with two or more wires 74. The wire sleeve 50 is firmly attached to the insulator 72 of the wire 74. The wire sleeve 50 can be a tubular heat shrink tube that has been shrunk onto the wire 74.

[0040] For optimal adhesion, the sleeve 50 can be a tubular heat shrink tube having an adhesive lining on its interior. During installation, when the tubular heat shrink tube is heated and shrunk, the adhesive lining melts and forms an adhesive layer 51 between the wire insulator 72 and the sleeve 50.

[0041] Now referring to Figure 3, the sleeve 50 cooperates with the stress relief plate 40 to prevent the wire 74 from being pulled backward out of the cable connector 1. For this purpose, the stress relief plate 40 includes a wire through-opening 41. The width of the through-opening 41 is just sufficient to accommodate a single wire 74, which includes an insulator 72 of the wire 74 within the exposed wire section 75 of the cable 70. The sleeve 50 rests on the stress relief plate 40 in the area adjacent to the through-opening 41. The tensile force applied to the cable 70 and transmitted through the cable 70 to the wire 74 is transferred into the stress relief plate 40 through the insulator 72 of the wire and the sleeve 50. The stress relief plate 40 is in turn supported on the circumferential outer portion by the connector housing 10.

[0042] As Figure 4 shown, a single through-opening 41 may have a semi-circular shape that extends into a rectangular slot 42. The rectangular slot 42 may form a radially entering slot 42 that is open at the side of the stress relief plate 40. The entering slot 42 allows the stress relief plate 40 to be installed after the sleeve 50 has been mounted on the wire. That is, the wire can be laterally pushed into the through-opening 41 along the length of the entering slot 42.

[0043] Also as Figure 4 illustrated, two adjacent through-openings 43, 44 may be connected by a generally rectangular connecting slot 45. The slot 45 may open outwardly into an engaging entering slot 46. In this configuration, two wires 74 can be inserted into the connecting slot 45 in a one-at-a-time manner laterally through the engaging entering slot 46 and from the connecting slot 45 into their final installed positions within the two adjacent through-openings 43, 44 of the two wires 74.

[0044] Figure 3 The stress relief plate 40 shown has a circular basic shape and is designed to accommodate a total of five wires. For this purpose, the stress relief plate 40 includes two pairs of connected through-openings 43, 44 and a single through-opening 41.

[0045] The spacer 47 extends forward from the center of the stress relief plate 40. As Figure 4 shown in the cross-sectional view, the tip 48 of the spacer 47 is pushed onto the terminal insert 30. At the same time, the circumferential outer portion 49 of the stress relief plate 40 abuts against the inwardly extending circular flange 11 of the housing 10. The stress relief plate 40 is thus firmly held within the cable connector 1 and is fixed to prevent tilting when subjected to asymmetric forces.

[0046] Figures 6 to 8Shows an alternative embodiment of a cable connector 2 having stress relief for each wire of a cable. The connector 2 includes a housing 110 and a terminal insert 130. A cable grommet 120 is connected to a rearward cable opening of the housing 110 by a cable grommet adapter 121.

[0047] Figure 7 A cross-sectional view shows a stress relief plate 140 disposed within the housing 110. An outer portion 145 of the stress relief plate 140 abuts an inner end of a cable entry guide 111 of the housing 110. The cable grommet adapter 121 is fixed around an opposite outer end of the cable entry guide 111. A seal 112 may be disposed between the cable grommet adapter 121 and the housing to prevent contaminants from entering the connector 2.

[0048] Figure 8 Is a perspective front view of the stress relief plate 140. For illustrative purposes, only one of five wire sleeves 150 is shown. The stress relief plate 140 has a generally rectangular shape with rounded corners. A circular through-opening 141 is disposed within the center of the stress relief plate 140. The central through-opening 141 is a circular hole, i.e., the central through-opening 141 includes two connected semi-circular sides. Four elongated through-openings 142 are arranged in a 2x2 matrix around the central through-opening 141 within the stress relief plate 140. Each elongated through-opening 142 has a stadium-shaped cross-section including two semi-circular portions 143, the two semi-circular portions 143 being adjacent to a rectangular slotted portion 144.

[0049] As Figure 8As shown, the surface of the cylindrical wire sleeve 150 abuts against the stress relief plate 140 in the region surrounding the through openings 141, 142. The width of the central through opening 141 corresponds to the diameter of the wire extending through the central through opening 141 during assembly. The diameter of the wire is the same as the inner diameter of the wire sleeve 150 that has been shrunk onto the wire insulator. Similarly, the diameter of the semi-circular portion 143 of the elongated through opening 142 and the width of the rectangular slotted portion 144 correspond to the outer diameter of the wire and thus to the inner diameter of the corresponding cylindrical wire sleeve 150. The shape difference between the cylindrical wire sleeve 150 and the elongated through opening 142 causes the wire sleeve 150 to abut against the stress relief plate 140 only with the overlapping portion 155 of the wire sleeve 150. The non-overlapping portion 156 of the cylindrical wire sleeve 150 extends above the slotted portion 144. That is, the elongated through opening 142 is greater in the longitudinal direction than the through opening required to accommodate the wire extending through the elongated through opening 142. This allows the stress relief plate 140 to be assembled after the terminal has been crimped to the wire. The through openings 141, 142 are large enough to allow the terminal to pass through the respective openings 141, 142. At the same time, the through openings 141, 142 are small enough in the width direction to prevent the cylindrical wire sleeve 150 from moving backward within the connector 2.

[0050] The cylindrical wire sleeves 50, 150 can be formed from a heavy-duty shrink tube. Such a tube can have a shrink ratio of 3:1, which allows the wire sleeves 50, 150 to slide over the terminals that have been crimped to the wire. Then, the wire sleeves 50, 150 can be fixed to the wire by heating the cylindrical wire sleeves 50, 150 and causing the cylindrical wire sleeves 50, 150 to shrink. The cylindrical wire sleeves 50, 150 can be made substantially of an irradiated modified polyolefin. The cylindrical wire sleeves 50, 150 can include a hot melt adhesive lining located on the inside of the sleeve. Upon heating, the sleeve shrinks and the adhesive melts to form a secure bond with the wire insulator.

[0051] The assembly of the connector 2 with the disclosed stress relief involves several steps. These steps can be performed in any technically feasible order. In an early step, the cable grommet 120, the cable grommet adapter 121, and the housing 110 are placed on the cable. The end of the cable 70 is stripped by removing the outer sheath 71 of the cable 70 to expose the wires 74 in the exposed wire section 75. At the end of each wire 74, the insulator 72 is removed to expose the conductor 73 in the exposed conductor section 76. A terminal is crimped, screwed, or clamped onto the conductor 73. The retaining plate 140 is placed on the cable such that one wire slides through each of the through openings 141, 142. Thereafter, a wire sleeve 150 is placed on each wire. The wire sleeve 150 is aligned to rest on the stress relief plate 140. Then, the wire sleeve 150 is fixed in place by applying heat, for example by using a hot air gun. The heat causes the wire sleeve 150 to shrink and firmly attach to the insulator 72 of the wire 74. The heat can also cause the adhesive layer within the wire sleeve 150 to melt and form an adhesive bond between the respective polyolefin sleeve 150 and the wire insulator 72. The terminal 131 is inserted into the terminal insert 130, and in turn, the terminal insert 130 is fixed to the housing 110.

[0052] The assembly of connector 1 generally follows the same steps performed in any technically feasible order. In the case where the stress relief plate 40 is used in connector 1, the wires do not need to be routed through any through openings 41, 43, 44. Instead, the respective wires can be laterally inserted through the corresponding entry slots 42, 46 and pushed into place. This allows the stress relief plate 40 to be installed even after the wire sleeve 50 has been fixed to the wire 74. In contrast, the entry plate 140 must be placed on the wire 74 before the wire sleeve 150 is fixed to the wire 74. Either connector 1 or 2 allows the terminals 31, 131 to be installed before the respective stress relief plates 40, 140 are placed on the wire 74.

[0053] Although connectors 1 and 2 are shown as having a rear-facing cable outlet, the disclosed stress relief system can be applied, with necessary modifications, to connectors having a cable side outlet.

[0054] Although connectors 1 and 2 are shown as having a common cable grommet providing a sealed fit of the cable to the housing, other cable entry protection concepts can also be used. For example, a clamping cable grommet can be used to provide a second form of stress relief.

[0055] Connectors 1 and 2 are shown as having stress relief plates 40 and 140. This only illustrates one possible shape of the stress relief element, and various other shapes can be used. For example, a hemispherical stress relief element can be used. In this case, the flat front face of the hemispherical stress relief element can support one or more wire sleeves. The spherical back of the hemispherical stress relief element can be supported in a corresponding spherical socket of the housing.

[0056] Connectors 1 and 2 are shown as having a stress relief element that is a separate part from the housing. This is also just one possible configuration. In an alternative configuration, the stress relief element can be an integrally formed part of the housing. For example, the housing and the stress relief element can be injection molded as one piece.

[0057] Figure 2 The terminal insert 30 is shown as being held within the frame 60 and the frame 60 is fixed to the housing 10. Of course, the terminal insert can also be directly fixed to the housing without using an intermediate frame. The terminal insert is generally an insulator adapted to hold terminals.

[0058] Although the invention has been described with reference to exemplary embodiments, it will be apparent to those skilled in the art that the invention is not limited to the disclosed or illustrated embodiments, but rather, the invention is intended to cover many other modifications, alternatives, variations, and broad equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A cable connector (1, 2), comprising: A housing (10, 110) having a cable opening for receiving a cable (70) passing through the cable opening, the cable (70) having a plurality of wires (74); A terminal insert (30, 130); A plurality of terminals (31, 131) arranged within the terminal insert (30, 130), each of the terminals (31, 131) being connected to a respective conductor (73) within one of the plurality of wires (74); A stress relief element (40, 140) including through openings (41, 43, 44, 141, 142); And A wire sleeve (50, 150) firmly connected to one or more of the wires (74) in an exposed wire section (75) of the cable (70) between the stress relief element (40, 140) and the terminals (31, 131).

2. The cable connector (1, 2) according to claim 1, Among them, The through openings (41, 43, 44, 141, 142) have a width and a length, and Wherein, an outer diameter of the wire sleeve (50, 150) exceeds the width of the through openings (41, 43, 44, 141, 142).

3. The cable connector (1, 2) according to claim 1, Among them, The through openings (41, 43, 44, 142) have a width and a length, the length being greater than the width, and Wherein, an outer diameter of the wire sleeve (50, 150) exceeds the width of the through openings (41, 43, 44, 142) and is shorter than the length of the through openings (41, 43, 44, 142).

4. The cable connector (1, 2) according to any one of claims 1 to 3, Among them, An outer portion (49, 145) of the stress relief element (40, 140) is supported within the housing (10, 110), Wherein, the wire sleeve (50, 150) transfers a tensile force acting on the one or more wires (74) through the cable (70) into the stress relief element (40, 140), and Wherein, the stress relief element (40, 140) transfers the tensile force into the housing (10, 110).

5. The cable connector (1, 2) according to any one of claims 1 to 4, Among them, The through openings (41, 43, 44, 141, 142) include semi-circular portions, a diameter of the semi-circular portions corresponding to a diameter of a corresponding one of the wires (74).

6. The cable connector (1, 2) according to any one of claims 1 to 5, Among them, The stress relief element (40) includes a plurality of through openings (41, 43, 44), Among them, two through openings (43, 44) of the plurality of through openings are connected by a connecting groove (45), and Among them, an access groove (46) extends from the side of the stress relief element (40, 140) to the connecting groove (45).

7. The cable connector (1, 2) according to any one of claims 1 to 6, Among them, The stress relief element (40) includes a plurality of through openings (41, 43, 44), Among them, the plurality of through openings (41, 43, 44) include: Two pairs of connected through openings (43, 44), which can enter the two pairs of connected through openings (43, 44) from the side of the stress relief element (40) through the engaging access groove (46), and A single through opening (41), which can enter the single through opening (41) from the side of the stress relief element (40) through the access groove (42).

8. The cable connector (1, 2) according to any one of claims 1 to 4, Among them, The stress relief element (140) includes a plurality of through openings (141, 142), Among them, the plurality of through openings (141, 142) include: A circular through opening (141), and the circular through opening (141) is centrally arranged between the following through openings: Four stadium-shaped through openings (142).

9. The cable connector (1, 2) according to any one of claims 1 to 8, further includes a spacer (47), and the spacer (47) extends forward from the stress relief element (40).

10. The cable connector (1, 2) according to any one of claims 1 to 9, Among them, The wire sleeves (50, 150) are substantially made of polyolefin.

11. The cable connector (1, 2) according to any one of claims 1 to 10, It further includes a hot melt adhesive layer (51) located between the wire sleeves (50, 150) and one or more of the wires (74) in the wire (74).

12. A method for installing a cable connector (1, 2) to a cable (70), the method includes: Inserting the cable (70) through the cable opening of the housing (10, 110); Arranging the wires (74) of the cable (70) to extend through the through openings (41, 43, 44, 141, 142) of the stress relief element (40, 140); Sliding a plurality of wire sleeves (50, 150) onto the wires (74), and each of the wire sleeves (50, 150) is placed on one of the wires (74) in the exposed wire section (75) of the cable (70); Applying heat to the wire sleeves (50, 150), thereby causing the wire sleeves (50, 150) to shrink and firmly connect to the wires (74); Inserting the terminals (31, 131) of each wire (74) into the terminal inserts (30, 130); And Connect the terminal insert (30, 130) to the housing (10, 110).

13. The method according to claim 12, Among them, applying heat to the wire sleeve (150) is performed after arranging the wire (74) of the cable (70) to extend through the through openings (141, 142) of the stress relief element (140), and wherein arranging the wire (74) of the cable (70) to extend through the through openings (141, 142) of the stress relief element (140) includes routing the wire (74) and the attached terminals (31, 131) through the through openings (141, 142) of the stress relief element (40, 140).

14. The method according to claim 12, Among them, arranging the wire (74) of the cable (70) to extend through the through openings (41, 43, 44) of the stress relief element (40) includes laterally passing one of the wires (74) through an entry slot (42, 46) and sliding it into one of the through openings (41, 43, 44).

15. The method according to any one of claims 12 to 14, Among them, applying heat to the wire sleeve (50, 150) includes: melting an adhesive lining on the interior of the wire sleeve (50, 150), and forming an adhesive bond between the wire sleeve (50, 150) and the wire (74).

Images