DESC:FIELD OF THE INVENTION
[001] The present invention relates to electrical cable glands and, more particularly to electrical cable glands used with armored cables.
BACKGROUND OF THE INVENTION
[002] Cable glands are commonly used to anchor and secure the end of an electrical cable to an electrical equipment by passing through the wall of the electrical equipment enclosure. Cable gland also seals cable entries to junction boxes for increased safety, particularly in hazardous environments, and provide a leak proof seal to prevent the ingress of moisture and dirt into the interior of the electrical equipment.
[003] Cable glands are mechanical cable entry devices used throughout a number of industries in conjunction with cable and wiring in electrical instrumentation and automation systems. Cable glands may be used on all types of electrical power, control, instrumentation, data and telecommunications cables. They are used as a sealing and termination device to ensure that the characteristics of the enclosure which the cable enters can be maintained adequately. Cable glands are made of various materials including plastics, steel, brass or aluminum.
[004] An armored cable is an assembly of multiple stranded conductors in an extruded core of moisture resistant, flame resistant non-metallic material, covered with an overlapping metal armor and jacketed with an extruded non-metallic material that is resistant to destructive environmental conditions. The armor is usually made of interlocking or continuous aluminum or stainless steel, or a metal tape. It should also be noted that the wire shield consists of suitably wrapped grounding
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conductors. Such cable, because of the double jacketing and the grounding conductors situated between the two jackets, provides more mechanical protection to the conductors which are located at the cable core, in addition to providing a low impedance electrical path for ground fault currents.
[005] The use of armored cables with an elastomer sheath covering is nowadays common in the electrical industry where there is a need to withstand harsh environmental conditions. These cables need special connectors to provide the connection between the cable and the equipment enclosure.
[006] The cable glands for the armored cable referred herein as armored cable glands help to assemble the armored cable and fit to ensure electrical continuity for grounding of armor between the sheathing of the electrical equipment at which the cable terminates.
[007] Currently available cable glands include a main body with a cone body and a cone ring which is used to grab the armor. The cone of the cone body is housed inside the main body along with a sealing member, holding the entire assembly of cable gland. In total, around seven individual components of a cable gland come together to do the anchoring and sealing for ingress protection.
[008] More number of components increase the cost and complexity of the cable gland and if a single component is lost during installation then the gland is not usable and another cable gland needs to be used. So, it is better to have few components which can be installed and manufactured easily.
[009] Also having more number of components in cable glands further increases the complexity while installing, and hence increasing the installation time.
[0010] In view of the limitations inherent in the available armored
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cable glands, there exists a need for an improved armored cable gland, which overcomes the disadvantages of the prior art and which can be used in a simple, cost effective, reliable, secure, ease of installation and environmentally friendly manner.
[0011] The present invention fulfils this need and provides further advantages as described in the following summary.
SUMMARY OF THE INVENTION
[0012] In view of the foregoing disadvantages inherent in the prior arts, the general purpose of the present invention is to provide an improved combination of convenience and utility, to include the advantages of the prior art, and to overcome the drawbacks inherent therein.
[0013] A primary objective of the present invention is to provide a cable gland assembly for mounting a cable having a core, an armor and an outer cover on an enclosure wall having a hole which is simple and cost effective.
[0014] In one aspect, the present invention provides a cable gland assembly for mounting a cable having a core, an armor and an outer cover on an enclosure wall having a hole. The cable gland assembly includes a cone body having a hollow cylindrical portion having external threads, a conical portion and a hexagonal collar dividing the cylindrical portion into a first portion and a second portion, a lock nut having internal threads adapted to engage with the external threads of the first portion and mount the cone body in the hole of the enclosure wall, an IP seal to provide ingress protection to the cable gland assembly, a cone ring having a hollow cylindrical structure with external threads on its outer surface and a taper on its inner surface, the cone ring is adapted to grip the armor on the conical portion of the cone body, an end nut having a hollow cylindrical structure
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with internal threads adapted to engage with the external threads of the second portion of the cone body and contain the cone ring between the cone body and the end nut, a seal disposed adjacent to the cone ring for preventing any leakage of liquid and gas across the enclosure wall through the cable gland assembly and a retaining ring disposed inside the end nut to abut against the seal and compress the seal when the end nut is tightened to engage with the cone body.
[0015] In another aspect of the present invention, the core passes through the cone body and the cone body electrically connects the armor to a ground potential when the cable is installed.
[0016] In yet another aspect of the present invention, the end nut comprises a front portion, a rear portion and a hexagonal collar separating the front portion and the rear portion.
[0017] In another aspect of the present invention, the front portion includes a step inside it along the length of the end nut located adjacent to the hexagonal collar, such that the step has internal threads adapted to engage with the external threads of the cone ring.
[0018] In yet another aspect of the present invention, the end nut further includes a cavity for housing the seal and the retaining ring in the end nut, the cavity starts after the step along the length of the end nut towards the rear portion of the end nut and ends with a recess proximal to the rear portion to prevent the seal and retaining ring coming out of the end nut on installation of the cable gland assembly.
[0019] In a further aspect of the present invention, the core passes through the cone body in such a way, that when the cable gland is installed, the first portion and the second portion of the cone body are located inside and outside of the enclosure wall respectively.
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[0020] In another aspect of the present invention, the seal consists of a hollow cylindrical structure with two walls at its ends radially extending above the diameter of the cylindrical structure, such that when the seal is compressed along the axial direction the two walls come closer to seal the cable gland assembly. The seal may be made of elastomer or similar material with a compression set 10% +/- 5% and hardness of 65 +/- 10 shore oA.
[0021] In yet another aspect of the present invention, the retaining ring consists of a cylindrical structure with a protruded ring at one end.
[0022] In another aspect of the present invention, the taper of the cone ring corresponds with the conical portion of the cone body.
[0023] In a further aspect of the present invention, the conical portion of the cone body includes axial grooves on its surface that assist in securing the cable armor on the cone body.
[0024] In another aspect of the present invention, the IP seal is mounted in a groove on the second portion of the cone body besides the hexagonal collar.
[0025] These together with other aspects of the invention, along with the various features of novelty that characterize the invention, are pointed out with particularity in the description annexed hereto and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be made to the accompanying drawings and descriptive matter in which there are illustrated exemplary embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
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[0026] The advantages and features of the present invention will become better understood with reference to the following more detailed description taken in conjunction with the accompanying drawings in which:
[0027] FIG. 1 illustrates an exploded view of the armored cable gland showing different components, according to one embodiment of the present invention;
[0028] FIG. 2 illustrates a schematic view of cone body, according to one embodiment of the present invention;
[0029] FIG. 3 illustrates a schematic view of cone ring, according to one embodiment of the present invention;
[0030] FIGs. 4A and 4B illustrates schematic and cross-sectional view respectively of the end nut, according to one embodiment of the present invention; and
[0031] FIG. 5 illustrates a schematic view of the assembled armored cable gland with cable, according to one embodiment of the present invention.
[0032] Like reference names refer to like parts throughout the several views of the drawings.
DETAILED DESCRIPTION OF THE DRAWINGS
[0033] In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without these specific details.
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[0034] As used herein, the term ‘plurality’ refers to the presence of more than one of the referenced item and the terms ‘a’, ‘an’, and ‘at least’ do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.
[0035] Reference herein to “one embodiment” or “another embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the invention. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Further, the diagrams representing one or more embodiments of the invention do not inherently indicate any particular order nor imply any limitations in the invention.
[0036] The terms “cable gland” or “cable gland assembly" interchangeably used in the present description, conveys the same meaning and both refer to the same object.
[0037] Referring to FIG. 1, which illustrates an exploded view of the cable gland assembly 10 showing different components, according to one embodiment of the present invention. The cable gland assembly 10 comprises a lock nut 12, a cone body 14, an IP seal 16, a cone ring 18, a seal 20, a retaining ring 22 and an end nut 24. The cable gland assembly 10 is used for mounting the cable 30 having a core 32, an armor 34 and an outer cover 36 on an enclosure wall (not shown) having an hole.
[0038] Referring to FIG. 2, the cone body 14 has a hollow cylindrical portion having external threads, a conical portion 14C and a hexagonal collar 14H dividing the cylindrical portion into a first portion 141 and a
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second portion 142. The first portion 141 is adapted to be engaged with the lock nut 12 and the second portion 142 with the end nut 24. The lock nut 12 is a hexagonal nut with internal threads such that the internal threads are adapted to engage with the external threads of the first portion 141 and mount the cone body 14 in the hole of the enclosure wall. The lock nut 12 holds and mounts the cable gland 10 on the enclosure.
[0039] The cone body 14 fits on the enclosure wall and is further held via the lock nut 12 from inside of the enclosure. It further provides additional support for griping cable armor 34 and electrically connects it to ground for any earth leakage current. The core 32 passes through the cone body 14 and the cone body 14 electrically connects the armor 34 to a ground potential when the cable 30 is installed. The inner and outer diameters of the cone body 14 are designed as per the diameter of the cable 30 and the hole for cable gland in the enclosure respectively. The part of the cone body 14 which is adapted to be engaged with the end nut 24, is the conical portion 14C on which the cable armor 34 rests and the cable core 32 passes through the hole of the cone body 14. In one embodiment of the present invention, the conical portion 14C includes axial grooves 14G on its surface that assist in securing the cable armor 34 on the cone body 14.
[0040] The lock nut 12 and the cone body 14 are placed on inner and outer sides of the enclosure wall respectively and the lock nut 12 is rotated to mount the cone body 14 on the enclosure wall. In one embodiment of the present invention, the IP seal 16 is mounted in a groove on the second portion 142 of the cone body besides the hexagonal collar 14H. The IP seal 16 provides the ingress protection to the cable gland assembly 10 from the joint between the cone body 14 and the end nut 24. This further adds to the sealing effect provided by the seal 20. The IP seal 16 may be made of Neoprene or any natural or synthetic rubber type material.
[0041] Referring to FIG. 3, that illustrates a schematic view of the
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cone ring 18. The cone ring 18 is a hollow cylindrical structure with external threads 181 on its outer surface and a taper 182 on its inner surface. In one embodiment of the present invention, the taper 182 of the cone ring corresponds with the conical portion 14C of the cone body. The cone ring 18 is adapted to grip the armor 34 on the conical portion 14C of the cone body. The end nut 24 pushes the cone ring 18 over the cable armor 34 and seals it from dust and outside environment. The inner surface of the cone ring 18 is tapering which provides knife-point anchoring. It further includes a plurality of slots 183 on the periphery of the ring along one of its edge. These slots assist in pre-assembly of cone ring 18 into the end nut 24. The cone ring 18 may include a chamfer on one of its side for easy insertion of cable 30 through it.
[0042] The seal 20 is disposed adjacent to the cone ring 18 for preventing any leakage of liquid and gas across the enclosure wall through the cable gland assembly 10 and a retaining ring 22 is disposed inside the end nut 24 to abut against the seal 20 and compress the seal when the end nut 24 is tightened to engage with the cone body 14.
[0043] In one embodiment of the present invention, the seal 20 consists of a hollow cylindrical structure with two walls at its ends radially extending above the diameter of the cylindrical structure, such that when the seal 20 is compressed along the axial direction the two walls come closer to seal the cable gland assembly 10. In one embodiment of the present invention, the seal 20 may be made of elastomer or similar material with a compression set 10% +/- 5% and hardness of 65 +/- 10 shore oA.
[0044] Referring to FIGs. 4A and 4B, that illustrates a schematic and cross-sectional views respectively of the end nut 24, according to one embodiment of the present invention. The end nut 24 is a hollow cylindrical structure with internal threads 50 adapted to engage with the external threads of the second portion 142 of the cone body and contain the cone
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ring 18 between the cone body 14 and the end nut 24. In one embodiment of the present invention, the end nut 24 comprises a front portion 241, a rear portion 242 and a hexagonal collar 24H separating the front portion 241 and the rear portion 242. The hexagonal collar 24H is located around the external surface, proximal to the rear portion 242 of the end nut and provides a grip while rotating the end nut 24 over the cone body 14 to form the cable gland assembly 10.
[0045] In one embodiment of the present invention, the front portion 241 includes a step 55 inside it along the length of the end nut 24 located adjacent to the hexagonal collar 24H, such that the step 55 has internal threads adapted to engage with the external threads of the cone ring 18. The step 55 is created in the end nut 24 at a predetermined distance along the length such that the step 55 has a diameter less than the internal threads of the front portion 50. The step 55 is straight and also includes threads on its surface hereafter referred to as ‘step threads’ 60. The diameter of the step 55 created is such that the step threads 55 corresponds with the outer threads of the cone ring 18. The cone ring 18 when inserted in the end nut 24 engages with the step threads 60 on rotation. The engagement of cone ring 18 with end nut 24 may be in either direction.
[0046] The dimensions of the step 55 and step threads 60 are decided based on the dimensions of the cone ring 18. The width of the step 55 may be less than the width of the cone ring 18. While engaged with the step threads 60, the cone ring 18 when rotated travels inside the end nut 24 towards the rear portion 242 of the end nut.
[0047] The end nut 24 further includes a cavity 65 for housing the seal 20 and the retaining ring 22 in the end nut 24. The cavity starts after the step 55 along the length of the end nut 24 towards the rear portion 242 of the end nut. The retaining ring 22 consists of a cylindrical structure with a protruded ring at one end. The cavity 65 ends with a recess 70 proximal
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to the rear portion 242 to prevent the seal 20 and retaining ring 22 to come out of the end nut on installation of the cable gland 10. The protruded ring of the retaining ring 22 abuts against the recess 70 and prevents any movement outside the end nut 24. Both the seal 20 and the retaining ring 22 may be made from an elastically deformable material known in the art, such as rubber or plastic.
[0048] As the end nut 24 is tightened, the interior threads 50 of the front portion 241 of the end nut engages with the external threads of the cone body 14 and the cone ring 18 is being pushed to firmly fasten the cable armor 34 over the conical portion 14C of the cone body to provide overall anchoring arrangement to the cable gland 10. This facilitates fastening and electrical grounding effects. It is to be noted that the cone ring 18 may be made of any metallic material such as brass or nickel-plated brass material.
[0049] Referring to FIG. 5, that illustrates a cross sectional view of the assembled cable gland 10 with the armored cable 30, according to one embodiment of the present invention. The lock nut 12 engages with the cone body 14 to mount it on an enclosure wall. The retaining ring 22 and the seal 20 are inserted in the cavity 65 of the end nut as per their predefined positions and then the cone ring 18 is also installed on the step threads 60 of the end nut. Now the prepared armored cable 30 with its armor 34 peeled up to predefined length, is inserted from the rear portion 242 of the end nut, such that the cable core 32 passes from the end nut through the retaining ring 22, seal 20 and the cone ring 18 to the cone body 14 with the cable armor 34 resting on the conical portion 14C of the cone body.
[0050] The cable armor 34 is gripped between the inner wall of the cone ring 18 and the outer surface of the conical portion 14C of the cone body. The IP seal 16 is mounted on the groove on the cone body 14. Now when the end nut 24 is aligned with the cone body 14 and rotated, the cable armor 34 gets gripped tightly between the cone body 14 and the cone ring
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18 and on further rotation of end nut 24, the cone ring 18 also rotates along the step threads 60 of the end nut. The outer threads of the cone ring 18 engaged with the step treads 60 of the end nut, allows a free rotation of the cone ring 18 over the armor 34 of the cable until a contact is made between the armor 34 and the cone ring 18. Further the cone ring 18 firmly fastens the armor 34 in the cone body 14 and playing a role in both retention of the cable and enabling the ground shield effect. Further rotation of the end nut 24 allows free rotation over threads of cone ring 18 while the cone ring 18 stays in place over anchored armor 34 while simultaneously the seal 20 is pushed and squeezed against the cone ring 18 by the end nut 24. This action squeezes the seal 20 and the retaining ring 22 to provide the necessary sealing to the cable gland thus completing the installation of cable gland. The IP seal 16 also gets squeezed between the cone body 14 and the end nut 24. The rotation of the end nut 24 on the cone body 14 provides a dual function of pushing the cone ring 18 over the armor 34 and squeezing the seal 20 in the cavity 65 of the end nut.
[0051] The cable gland 10 of the present invention may be made of any material, such as plastic, nylon or any metal more preferably, brass, stainless steel, aluminum, copper, etc.
[0052] In one embodiment of the present invention, the seal 20 and retaining ring 22 are inserted in the cavity 65 of the end nut and the cone ring 18 is also installed to on the step threads 60, for retaining the seal 20 and retaining ring 22 in the cavity. This assembly may be provided as pre-assembled components of the cable gland, which reduces the installation steps to just inserting the cable 30 through the end nut 24 and tightening the cone body 14 over it. The pre-assembly may also reduce the time and labor required for installing the cable gland 10 at the site location. Since four of the components viz end nut 24, seal 20, retaining ring 22 and cone ring 18 are pre-assembled into one component, the chances of misplacing or losing any small component during transport or installation are significantly
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reduced.
[0053] The reduced number of components in the cable gland 10 of the present invention as compared to the cable gland of prior art also gives advantage in terms of reduction in weight and cost of material for the cable gland.
[0054] The cable gland 10 of the present invention may provide advantages as below:
- Novel design with reduced components encompassing all cable gland working features results in overall weight reduction
- Cost of making an extra component, i.e. main body which was in the prior art cable glands is also reduced and hence reducing the overall cost and manufacturing process steps
- Ease of installation: Pre-assembled components needs less effort to install the cable gland at site
- Tools: No expensive or complex tools are required for installing tightening the cable gland. Existing tools are sufficient for installation.
[0055] Although an exemplary embodiment of the invention has been disclosed in detail for illustrative purposes, it will be recognized to those skilled in the art that variations or modifications of the disclosed invention, including the rearrangement in the configurations of the parts, changes in steps and their sequences may be possible. Accordingly, the invention is intended to embrace all such alternatives, modifications and variations as may fall within the spirit and scope of the present invention.
[0056] The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching.
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[0057] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the appended claims. ,CLAIMS:WE CLAIM:
1. A cable gland assembly (10) for mounting a cable (30) having a core (32), an armor (34) and an outer cover (36) on an enclosure wall having a hole, the cable gland assembly (10) comprising:
- a cone body (14) having a hollow cylindrical portion having external threads, a conical portion (14C) and a hexagonal collar (14H) dividing the cylindrical portion into a first portion (141) and a second portion (142);
- a lock nut (12) having internal threads adapted to engage with the external threads of the first portion (141) and mount the cone body (14) in the hole of the enclosure wall;
- an IP seal (16) to provide ingress protection to the cable gland assembly,
- a cone ring (18) having a hollow cylindrical structure with external threads on its outer surface and a taper on its inner surface, the cone ring (18) is adapted to grip the armor (34) on the conical portion (14C) of the cone body;
- an end nut (24) having a hollow cylindrical structure with internal threads (50) adapted to engage with the external threads of the second portion (142) of the cone body and contain the cone ring (18) between the cone body (14) and the end nut (24);
- a seal (20) disposed adjacent to the cone ring (18) for preventing any leakage of liquid and gas across the enclosure wall through the cable gland assembly; and
- a retaining ring (22) disposed inside the end nut (24) to abut against the seal (20) and compress the seal when the end nut (24) is tightened to engage with the cone body (14).
2. The cable gland assembly according to claim 1, wherein the core (32) passes through the cone body (14) and the cone body electrically connects the armor (34) to a ground potential when the cable (30) is installed.
3. The cable gland assembly (10) according to claim 1, wherein the end nut (24) comprises a front portion (241), a rear portion (242) and a hexagonal
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collar (24H) separating the front portion (241) and the rear portion (242).
4. The cable gland assembly (10) according to claim 3, wherein the front portion (241) includes a step (55) inside it along the length of the end nut located adjacent to the hexagonal collar (24H), such that the step (55) has internal threads (60) adapted to engage with the external threads of the cone ring (14).
5. The cable gland assembly (10) according to claim 4, wherein the end nut (24) further includes a cavity (65) for housing the seal (20) and the retaining ring (22) in the end nut, the cavity (65) starts after the step (55) along the length of the end nut towards the rear portion (242) of the end nut and ends with a recess (70) proximal to the rear portion to prevent the seal and retaining ring coming out of the end nut on installation of the cable gland assembly.
6. The cable gland assembly according to claim 1, wherein the core (32) passes through the cone body (14) in such a way, that when the cable gland (10) is installed, the first portion (141) and the second portion (142) of the cone body are located inside and outside of the enclosure wall respectively.
7. The cable gland assembly according to claim 1, wherein the seal (20) consists of a hollow cylindrical structure with two walls at its ends radially extending above the diameter of the cylindrical structure, such that when the seal (20) is compressed along the axial direction the two walls come closer to seal the cable gland assembly.
8. The cable gland assembly according to claim 1, wherein the seal is made of elastomer or similar material with a compression set 10% +/- 5% and hardness of 65 +/- 10 shore oA
9. The cable gland assembly according to claim 1, wherein the retaining ring
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consists of a cylindrical structure with a protruded ring at one end.
10. The cable gland assembly according to claim 1, wherein the taper of the cone ring corresponds with the conical portion of the cone body.
11. The cable gland assembly according to claim 1, wherein the conical portion (14C) of the cone body includes axial grooves (14G) on its surface that assist in securing the cable armor (34) on the cone body (14).
12. The cable gland assembly according to claim 1, wherein the IP seal (16) is mounted in a groove on the second portion (142) of the cone body besides the hexagonal collar (14H).