1. Field of the Invention
The present invention relates to a cable gland, which may be employed on fiber optic cables, coaxial cables, twisted pair cables, or other types of cables or elongated objects. More particularly, the present invention relates to a cable gland having a two-piece fitting and two-piece compression nut, which can be assembled around any portion of a cable.
2. Description of the Related Art
Cable glands are well known in the existing arts. A cable gland is generally a structure which is mechanically fixed to an outer jacket of a cable, typically by a frictional fit or possibly an adhesive. The cable gland also has attachment features which allow the cable gland to be attached to a secondary object, such as a housing, plate, or guide. The cable gland thereby provides strain relief to the cable. In other words, a pulling force applied to the cable's jacket will be transmitted, via the jacket, to the cable gland and hence to the secondary object (e.g., housing). Therefore, the pulling force on the cable will not pass beyond the secondary object (e.g., into the housing to disturb a termination of the cable to the equipment within the housing).
As seen in
A second end of the fitting 16 is provided with a second male thread 20 for receiving a compression nut 21 having a complimentary female thread 25. A longitudinal bore through the fitting 16 is substantially uniform from the outer end of the first male thread 15 to a point intermediate the projecting section 17 and the outer end of the second male thread 20. Then, the bore is outwardly tapered at the compression nut end of the fitting 16 to form a conical seat 22. The conical seat 22 is similar in shape to a conical body portion 23 of a deformable gland 24. The gland 24 is formed of a resilient elastomer, such as Neoprene, and includes a bore 26 extending along its central axis. The bore 26 has a diameter which is slightly greater than the outer diameter of the largest cable 13 that the gland 24 is designed to accommodate.
When the gland 24 is placed in the fitting 16 without compression, the conical body portion 23 seats against the conical seat 22 of the fitting 16, and the gland 24 projects outwardly from the fitting 16 by about one-half of its length. When the gland 24 is axially compressed by screwing the compression nut 21 onto the second male thread 20, the gland wall defining the bore 26 presses tightly upon the outer jacket of the cable 13 and thereby seals that interface against the passage of liquid. Concurrently, the conical body potion 23 of the gland 24 compresses tightly in the conical seat 22 of the fitting 16 and seals that interface against the passage of liquid.
The outer end of the gland 24 may include a short taper 27. The short taper 27 matches an internal taper formed within the compression nut 21, as best seen in
The Applicants have appreciated one or more drawbacks associated with the designs of the prior art.
With cable glands of the prior art, the cable gland must be installed over the cable prior to terminating the cable. In other words, the component parts of the cable gland must be threaded over the cable 13 before the electrical conductors 11 are terminated to connectors. This requirement can be particularly troublesome in the case of preterminated cables.
Many customers of fiber optic cables prefer that the cables have factory installed terminals, such as ST-type or LC-type terminals, at each end. Customers may believe that factory installed terminals are of a higher quality than terminals installed by a field technician. Therefore, the customer may purchase standard length preterminated fiber optic cables, such as a 6 foot fiber optic cable having ST-type connectors at each end. If a field technician is required to install this preterminated fiber optic cable between two female connectors, there is no structure available in the existing art to permit a cable gland to be subsequently installed mid-span of the cable and used along the length of the preterminated cable.
One solution would be to preinstall the cable gland components onto the fiber optic cable at the factory prior to installing the two end terminals. However, this is not an optimum solution in that not all fiber optic cables will need a cable gland in the final installation and then the component parts go unused and are left dangling on the cable. This creates excess bulk in the cable management space and is seen as undesirable by the customer. Also, in some installations a single preterminated fiber optic cable may require two or more cable glands. It is not economically feasible for installers to inventory, store and carry multiple lengths of preterminated fiber optic cables with various numbers of loose cable gland parts preinstalled thereon.
The Applicants have appreciated a need in the art for a cable gland having component parts which can be installed laterally over any mid-span portion of a cable to permit a user to fix the cable to a secondary object, instead of having to thread a cable end through a bore within the component parts of the cable gland.
It is an object of the present invention to address one or more of the drawbacks of the prior art cable gland designs and/or Applicants' appreciated needs in the art.
This and other objects are accomplished by a removable cable gland including a two-piece fitting which may be laterally assembled over a cable, as opposed to a cable being fed through an opening in the fitting. A two-piece compression nut may also be laterally assembled over the cable. The two pieces of the compression nut are slid together along a longitudinal direction of the cable by a tongue and groove arrangement. The two pieces of the fitting are plugged together in a direction perpendicular to the longitudinal direction of the cable. Once first threads of the fitting are engaged to second threads of the compression nut, the two-piece fitting is locked together by the surrounding compression nut. Simultaneously, the two-piece compression nut is locked together, such that the tongue may not slide longitudinally relative to the groove, due to the first and second thread engagement.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limits of the present invention, and wherein:
The present invention now is described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
Like numbers refer to like elements throughout. In the figures, the thickness of certain lines, layers, components, elements or features may be exaggerated for clarity. Broken lines illustrate optional features or operations unless specified otherwise.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the specification and relevant art and should not be interpreted in an idealized or overly formal sense unless expressly so defined herein. Well-known functions or constructions may not be described in detail for brevity and/or clarity.
As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. As used herein, phrases such as “between X and Y” and “between about X and Y” should be interpreted to include X and Y. As used herein, phrases such as “between about X and Y” mean “between about X and about Y.” As used herein, phrases such as “from about X to Y” mean “from about X to about Y.”
It will be understood that when an element is referred to as being “on”, “attached” to, “connected” to, “coupled” with, “contacting”, etc., another element, it can be directly on, attached to, connected to, coupled with or contacting the other element or intervening elements may also be present. In contrast, when an element is referred to as being, for example, “directly on”, “directly attached” to, “directly connected” to, “directly coupled” with or “directly contacting” another element, there are no intervening elements present. It will also be appreciated by those of skill in the art that references to a structure or feature that is disposed “adjacent” another feature may have portions that overlap or underlie the adjacent feature.
Spatially relative terms, such as “under”, “below”, “lower”, “over”, “upper”, “lateral”, “left”, “right” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is inverted, elements described as “under” or “beneath” other elements or features would then be oriented “over” the other elements or features. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the descriptors of relative spatial relationships used herein interpreted accordingly.
The fitting 31 includes a first thread track 39 on one end of its outer circumferential surface, which is sized to cooperate with a second thread track 41 on an inside surface of the compression nut 33. The fitting 31 also includes a third thread track 43 on the other end of its outer circumferential surface, which is sized to cooperate with a fourth thread track 45 on an inside surface of the retention nut 37. An outwardly projecting abutment 47 is located proximate a mid-portion of the fitting 31. The fitting 31, compression nut 33 and retention nut 37 are preferably formed of a rigid material, like a plastic, such as nylon, filled nylon, or acrylonitrile-butadiene-styrene (ABS).
In a preferred embodiment, the first thread track 39 is a first screw thread and the second thread track 41 is a second screw thread. Therefore, the compression nut 33 may be moved along the fitting 31 by relative rotation between the compression nut 33 and the fitting 31. Also, the third thread track 43 is a third screw thread and the fourth thread track 45 is a fourth screw thread. Therefore, the retention nut 37 may be moved along the fitting 31 by relative rotation between the retention nut 37 and the fitting 31. The retention nut 37 may be screwed onto the fitting 31 toward the abutment 47, so that a secondary structure can be sandwiched between the retention nut 37 and the abutment 47.
The gland 35 is a generally conical member, sized to fit partially within the fitting 31 and the compression nut 33. The gland 35 includes a bore 49 being centrally located about a longitudinal axis of the conical shape. The gland 35 is preferably formed of an elastic material, such as a thermoplastic elastomer (TPE), rubber, NEOPRENE or Nitrile.
The procedure of the mounting the assembled component parts 31, 33, 35 and 37 of
As illustrated in
The compression nut 33 includes at least a third piece 61 with a third threaded portion 63 and a fourth piece 65 with a fourth threaded portion 67. The fourth piece 65 includes one or more tongues 69 protruding therefrom. The third piece 65 includes one or more grooves 71 formed therein to receive the tongues 69 when the third piece 61 and the fourth piece 65 are in a compression nut mating position. The grooves 71 may include stops 73 to abate further movement of the tongues 69 within the grooves 71 when the third and fourth pieces 61 and 65 reach the compression nut mating position. Preferably, a protrusion 70 is provided on an end edge of at least one of the tongues 69. In the compression nut mating position, the protrusion 70 snaps into a recess formed in a bottom wall of the mating groove 71 to form a detent arrangement, which holds the third and fourth pieces 61 and 65 together, such that the third and fourth pieces 61 and 65 may later be separated by a manual force. In the compression nut mating position, the third threaded portion 63 cooperates with the fourth threaded portion 67 to form the second thread track 41.
The first piece 51 of the fitting 31 also includes a fifth threaded portion 75. The second piece 55 of the fitting 31 also includes a sixth threaded portion 77. In the fitting mating position, the fifth threaded portion 75 cooperates with the sixth threaded portion 77 to form the third thread track 43.
The retention nut 37 includes at least a fifth piece 79 with a seventh threaded portion 81 and a sixth piece 83 with an eighth threaded portion 85. Similar to the compression nut 33, the sixth piece 83 includes one or more tongues 87 protruding therefrom. The fifth piece 79 includes one or more grooves 89 formed therein to receive the tongues 87 when the fifth piece 79 and the sixth piece 83 are in a retention nut mating position. The grooves 89 may include stops 91 to abate further movement of the tongues 87 within the grooves 89 when the fifth and sixth pieces 79 and 83 reach the retention nut mating position. A detent mechanism may also be provided between the two pieces 79 and 83 of the retention nut 37 in a same or similar manner as the detent mechanism described in relation to the two pieces 61 and 65 of the compression nut 33. In the retention nut mating position, the seventh threaded portion 81 cooperates with the eighth threaded portion 85 to form the fourth thread track 45.
As best seen in
Once the pieces of the component parts of the cable gland 30 are installed around a cable, the component parts are assembled one to another. As illustrated in
As illustrated in the cross sectional view of
When the component parts of the cable gland 30 are assembled as illustrated in
The first and second pieces 51 and 55 of the fitting 31 are free to be separated one from the other when the first and third thread tracks 39 and 43 are free of the compression nut 33 and retention nut 37. The first and second pieces 51 and 55 may be separated by applying a manual force to overcome the detent engagement caused by the protrusion 60. Of course, the detent engagement caused by the protrusion 60 is only optional in the present invention. If no protrusion 60 is provided, the first and second pieces 51 and 55 of the fitting 31 would simply separate when the compression nut 33 and retention nut 37 are freed from the fitting 31. The third and fourth pieces 61 and 65 of the compression nut 33 are free to be separated one from the other when the compression nut 33 is removed from the fitting 31. The third and fourth pieces 61 and 65 may be separated by applying a manual force to overcome the detent engagement caused by the protrusion 70. The fifth and sixth pieces 79 and 83 of the retention nut 37 are free to be separated one from the other when the retention nut 37 is removed from the fitting 31 by applying a manual force to overcome any detent engagement therebetween.
One modification of the present invention would be to remove the abutment 47 of the fitting 31. Instead of using an abutment 47, the cable gland 30 could be attached to a secondary structure 10 by two retention nuts 37 and 37′.
Although
Although the foregoing discussion has focused primarily on the use of the cable gland 30 with a fiber optic cable, it should be appreciated that the cable gland 30 could also work in combination with other cables, such as a coaxial cable, a jacketed twisted pair cable, a jacketed composite cable or a power cable. Although continuous thread tracks 39, 41, 43 and 45 have been illustrated, discontinuous thread tracks could be employed with brief gaps existing all along the thread track to conserve material costs and reduce the amount of material present to produce smoke in the case of a fire. Further, the thread tracks along the parting lines of a component (e.g., fitting, compression nut) could be removed. In other words, where the thread tracks of the two pieces of a component part come together, the thread tracks could be removed to prevent flash from entering the thread region and not allowing the compression nut 33 to screw onto the fitting 31. In the case of the fitting 31, this would basically be an extension of the flat spots 97 along the entire length of the fitting 31 along the seam between the two parts forming the fitting 31. Although a two piece retention nut 37 has been illustrated, the retention nut 37 could be replaced by a u-shaped clip which is screwed onto the second thread track 43 to sandwich a secondary structure between the u-shaped clip and the abutment 47. Although the bore 49 through the gland 35 has been illustrated with a circular cross sectional shape, the bore 49 could have other cross sectional shapes (e.g., oval), so that the cable gland could function with cables or other objects having outer cross sectional shapes other than circular, which match the cross sectional shape of the bore 49.
Although
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.