The present disclosure relates generally to equipment used in fiber optic communications networks. More particularly, the present disclosure relates to strain relief devices used in securing fiber optic cables to telecommunications equipment.
Fiber optic communication systems are becoming prevalent in part because service providers want to deliver high band width communication capabilities to customers. Fiber optic communication systems employ a network of fiber optic cables to transmit large volumes of data and voice signals over relatively long distances. A typical fiber optic network may include a system of trunk fiber optic cables including optical fibers. Fiber optic networks may include drop cables that interconnect to fibers of the trunk cables at various locations along the lengths of the trunk cables. The drop cables can be routed from the trunk cables to subscriber locations or to intermediate structures such as drop terminals.
Optical fibers of cables (e.g., drop cables, trunk cables, etc.) may often be connected to optical fibers of other cables in the network via splices (e.g., fusion splices). Splices are typically supported within splice trays. Splice trays protect splices (e.g., fusion splices) and manage the optical fibers routed to and from splice locations.
Being part of a fiber optic network, cables routed to and from telecommunications equipment such as splice trays may be exposed to pulling forces. It is desirable to provide effective strain relief for fiber optic cables that are secured or anchored to devices such as splice trays to limit damage to optical fibers within the cables.
Certain aspects of the present disclosure relate to effective arrangements for providing strain relief to fiber optic cables secured to telecommunications equipment such as splice trays.
According to one inventive aspect, the disclosure relates to a strain relief device for anchoring a fiber optic cable to telecommunications equipment, the strain relief device comprising a base defining a base channel having an open top and configured to receive at least a portion of the fiber optic cable from the open top, the base channel defining a longitudinal axis generally parallel to a longitudinal axis of the fiber optic cable when the fiber optic cable is placed within the base channel, the base further defining a first sliding coupling structure extending at a generally acute angle with respect to the longitudinal axis of the base channel along a top to bottom direction. The strain relief device further includes a cover defining a cover channel having an open bottom and configured to receive at least a portion of the fiber optic cable from the open bottom, the cover channel defining a longitudinal axis generally parallel to the longitudinal axis of the fiber optic cable when the fiber optic cable is placed within the cover channel, the cover further defining a second sliding coupling structure extending at a generally acute angle with respect to the longitudinal axis of the cover channel along a top to bottom direction, the first and second sliding coupling structures configured to slidably mate for advancing the cover channel toward the base channel to clamp the fiber optic cable in between the base and the cover.
According to another inventive aspect, the disclosure relates to a strain relief device for anchoring a fiber optic cable to telecommunications equipment, the strain relief device comprising a base defining a top side and a bottom side, the base defining a base channel having an open top and a closed bottom and configured to receive at least a portion of the fiber optic cable from the open top, the base channel defining a longitudinal axis generally parallel to a longitudinal axis of the fiber optic cable when the fiber optic cable is placed within the base channel, the base further defining a first sliding coupling structure extending at a generally acute angle with respect to the longitudinal axis of the base channel along a top to bottom direction. The strain relief device further includes a cover defining a top side and a bottom side, the cover defining a cover channel having an open bottom and a closed top and configured to receive at least a portion of the fiber optic cable from the open bottom, the cover channel defining a longitudinal axis generally parallel to the longitudinal axis of the fiber optic cable when the fiber optic cable is placed within the cover channel, the cover further defining a second sliding coupling structure extending at a generally acute angle with respect to the longitudinal axis of the cover channel along a top to bottom direction, the first and second sliding coupling structures configured to slidably mate for advancing the closed top of the cover channel toward the closed bottom of the base channel to clamp the fiber optic cable in between the base and the cover.
According to another inventive aspect, the disclosure relates to a strain relief device for anchoring a fiber optic cable to telecommunications equipment, the strain relief device comprising a base defining a bore having a tapered profile, wherein the bore defines a larger cross dimension at a first end than at a second end of the bore and a clamp structure defining a body configured for insertion into the bore, the body defining a tapered profile, wherein the body defines a larger cross dimension at a first end than at a second end of the body, the clamp structure further including a throughhole extending generally along a direction from the first end to the second end of the body for receiving a fiber optic cable. The base and the clamp structure are configured such that when the clamp structure is slidably inserted into the bore in a direction extending from the first end toward the second end of the bore, a fiber optic cable extending through the throughhole of the clamp structure is radially clamped within the clamp structure.
A variety of additional inventive aspects will be set forth in the description that follows. The inventive aspects can relate to individual features and to combinations of features. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the broad inventive concepts upon which the embodiments disclosure herein are based.
The present disclosure relates to arrangements and methods for providing effective strain relief to fiber optic cables that are anchored to telecommunications equipment.
Referring to
As will be discussed in further detail below, according to certain example applications, a fiber optic cable 22 entering the tray 10 may clamped to the tray 10 so as to reduce strain on the optical fibers 20 if the cable is exposed to pulling forces away from the tray 10. Once clamped, a number of the fibers 20 of the cable 22 may be broken out and routed through the one or more fiber management structures 18 for further splicing to fibers of other cables. Portions of the cable 22 that are not broken out may continue to the other end of the tray 10, wherein the cable 22 may once again be clamped or anchored to reduce strain on fibers caused by pulling forces originating from an exterior of the tray 10.
Referring now to
In the depicted embodiment, the strain relief device 24 is configured to be coupled to the tray 10 via a snap-fit interlock. According to the depicted example embodiment, the strain relief device 24 includes a pair of elastically flexible cantilever arms 28 with ramped tab portions 30. The cantilever arms 28 are configured to flex elastically inwardly and outwardly when the cable clamp 24 is being coupled to or removed from the mount portion 26 of the tray 10. The ramped tab portions 30 of the arms 28 act as catches to prevent removal after the clamp 24 has been mounted to the tray 10.
As will be described in further detail below, the cable clamp 24, in the depicted embodiment, also includes a plurality of ribs 32 along a base portion 34 of the clamp 24 that are configured to fit within keying slots 36 defined at the cable clamp mount 26 of the tray 10 for keying with and nesting within the mount 26.
It should be noted that the fiber management or splice tray 10 shown is simply one example of a piece of telecommunications equipment which the strain relief device 24 may be used with and is referred to and illustrated herein to describe the inventive aspects of the strain relief device 24. The strain relief device 24 can be used with a variety of other telecommunications equipment wherein a fiber optic cable 22 is anchored or secured to the equipment.
It should also be noted that although the strain relief device 24 is shown herein as being coupled to the splice tray 10 with a snap-fit interlock, the strain relief device 24 may be coupled to a piece of telecommunications equipment such as the splice tray 10 via a variety of other methods such as via adhesive, via ultrasonic welding, etc. The attachment methods can provide for removability of the strain relief device 24 such as shown or may provide for more permanent fixtures.
Also, even though the snap-fit interlock between the tray 10 and the depicted strain relief device 24 is provided via structures in the form of elastically flexible cantilever arms 28 that have ramped retaining tabs 30, the snap-fit interlock may be provided via other arrangements.
According to one example embodiment, the fiber optic cable 22 includes an outer jacket 38 surrounding one or more optical fibers 20. It will be appreciated that the outer jacket 38 of the cable 22 can be made of any number of different types of polymeric materials. In one embodiment, the outer jacket 38 is made of polyethylene. In the example embodiment, the cable 22 also includes a strength member 40 (i.e., a tensile reinforcing member) positioned within the outer jacket 38. According to one embodiment, the strength member 40 may be formed from flexible Kevlar fibers.
According to one example embodiment, the outer diameter 42 of the outer jacket 38 may be between 2.0 mm and 9.5 mm. According to certain examples, the outer diameter 42 of the outer jacket 38 may be between 8.0 mm and 9.5 mm. According to certain examples, the outer diameter 42 of the outer jacket 38 may be between 6.0 mm and 7.5 mm. According to certain examples, the outer diameter 42 of the outer jacket 38 may be between 4.0 mm and 5.5 mm. According to other example embodiments, the outer diameter 42 of the outer jacket 38 may be between 2.0 mm and 3.0 mm.
As will be described in further detail below, the outer jacket 38 and the strength member 40 of the fiber optic cable 22 is anchored to the splice tray 10 via the strain relief device 24 of the present disclosure. The strain relief device 24 is configured such that after a portion of the outer jacket 38 has been stripped, exposing the one or more optical fibers 20 and the strength member layer 40, the jacket 38 and the strength member 40 are clamped to the tray 10 via the strain relief device 24 and the optical fibers 20 continue to be routed through the tray 10 for splicing.
Still referring to
Referring to
The base 34 defines a first sliding coupling structure (e.g., an elongate groove 66) on each of the right side 56 and the left side 58. As will be discussed further below, each first sliding coupling structure in the form of the groove 66 is configured to receive a second sliding coupling structure in the form of an elongate ridge 68 on each of right and left sides 70, 72 of the cover 44 for clamping the cable 22. The ridges and the grooves 68, 66 define generally a dove-tail configuration such that while they can move with respect to each other in the sliding direction, they cannot be separated in any direction that is perpendicular to the sliding direction. It should be noted that in the depicted example, although the first sliding coupling structure 66 of the base has been provided in the form of a groove and the second sliding coupling structure 68 of the cover has been provided in the form of a ridge, the grooves 66 and the ridges 68 can be interchanged in the other examples to provide for the same functionality.
As shown in
Referring now to
When the cover 44 is slid over the base 34 in a direction from first end 48 toward the second end 50 of the base 34, the tapering interaction between the ridges 68 and the grooves 66 provides a radial clamping force on the outer jacket 38 of the cable 22. As the cover 44 is slid in a direction from the first end 48 toward the second end 50 of the base 34, due to the interaction between the ridges 68 and the grooves 66, the V-shaped channel 80 of the cover 44 gets closer to the V-shaped channel 60 of the base 34, applying a radial clamping force on the cable 22.
Regarding clamping of the strength member 40 that is exposed after the outer jacket 38 has been stripped, the base 34 defines a plurality of strength member retention structures 84 at the first end 48 thereof. In the depicted embodiment, the strength member retention structures 84 include a pair of forwardly extending posts 86 and a finger 88 having a downwardly extending portion provided generally thereinbetween.
The posts 86 and the finger 88 are configured such that individual strands of a portion of the exposed strength member 40 of the cable 22 can be wrapped therearound (e.g., in a figure-eight configuration) before directing the strength member 40 rearwardly through the channel 60 of the base 34 (see
The remaining portion of the strength member 40 that is exposed after the cable 22 is clamped can extend out from the second end 50 of the base 34 away from the telecommunications device.
As noted above, the base 34 may include a pair of elastically flexible cantilever arms 28 with ramped tab portions 30, one provided on each of the right side 56 and the left side 58. The cantilever arms 28 are configured to flex elastically inwardly and outwardly when the stain relief device 24 is being coupled to or removed from the mount portion 26 of the tray 10. The ramped tab portions 30 of the arms 28 act as catches to prevent removal after the clamp 24 has been mounted to the tray 10. As illustrated in
Although illustrated and described with a removable snap-fit interlock, the strain relief device 24 may be coupled to a piece of telecommunications equipment such as the splice tray 10 via a variety of other methods such as via adhesive, via ultrasonic welding, etc. The attachment methods can provide for removability of the strain relief device 24 such as shown or may provide for more permanent fixtures. In other embodiments, portions of the strain relief device 24 such as the base 34 may be integrally formed (e.g., injection molded) with telecommunications equipment such as the splice tray 10.
Also, even though the snap-fit interlock between the tray 10 and the depicted strain relief device 24 is provided by elastically flexible cantilever arms 28 that have ramped retaining tabs 30 and slots 90, the snap-fit interlock may be provided via other arrangements.
As also noted above, the cable clamp 24, in the depicted embodiment, also includes the plurality of ribs 32 along a base portion 34 of the clamp 24 that are configured to fit within keying slots 36 defined at the cable clamp mount 26 of the tray 10 for keying with and nesting within the mount 26.
As noted previously, fiber optic cables 22 may be provided in different sizes, wherein the outer jackets 38 of the cables 22 may define different diameters 42. For example, according to one embodiment, the outer diameter 42 of the outer jacket 38 may be between 8.0 mm and 9.5 mm. According to another embodiment, the outer diameter 42 of the outer jacket 38 may be between 6.0 mm and 7.5 mm. According to yet another embodiment, the outer diameter 42 of the outer jacket 38 may be between 4.0 mm and 5.5 mm.
As shown in
As shown, the base 34 defines a cutout 92 at each of the first end 48 and the second end 50 that receives a complementary structure at each of the first and second end 94, 96 of an insert 46 for removably placing the insert 46 within the base 34.
The channel 60 defined by the base 34 (as shown in
Each insert 46 also defines a generally V-shaped channel 95 and is configured to change the size of the channel 60 of the base 34 when used. Each insert 46 defines a plurality of notches 97 along the bottom of the insert 46 that are configured to fit over the teeth 64 of the base 34 when placed therein. Each insert 46 also defines similar teeth 99 along the channel 95 thereof for biting into the outer jacket 38 of the cable 22.
Referring now to
As noted previously, the strain relief device 100 may be mounted to the splice tray 10 via a variety of methods including a snap-fit interlock, via adhesives, via ultrasonic welding, etc. In the depicted embodiment, the strain relief device 100 is illustrated with a pair of elastically flexible cantilever arms 102 for providing a snap-fit interlock with another clamp mount 150 of the splice tray 10, as shown in
Still referring to
Referring now to
Each bore 110 defines a tapered configuration extending from the first end 112 of the base 106 to the second end 114 such that the bore 110 defines a larger cross dimension 124 at the first end 112 that tapers down to a smaller cross dimension 124 at the second end 114, forming a generally conical shape. Above each bore 110 is also defined an elongate groove 126 that extends along the top side 116 of the base 106. The groove 126 communicates with the conical bore 110. As will be discussed in further detail, the groove 126 is configured to provide a keying function with respect to each first clamp structure 104.
For each of the bores 110, the base 106 defines a notch 128 at a bottom side of the bore 110 that extends from the first end 112 to the second end 114 of the base 106. As will be discussed in further detail below, the notch 128 is configured to accommodate a strength member 40 of a fiber optic cable 22 that is anchored using the strain relief device 100.
Referring now to
A throughhole 140 of the first clamp structure 104 is configured to receive the outer jacket 38 of the fiber optic cable 22. In the depicted embodiment, once receiving the cable 22 therein, the first clamp structure 104 is slid into the bore 110, with the ridge 138 aligned with the groove 126, in a direction from the first end 112 toward the second end 114. As the first clamp structure 104 is slid toward second end 114 of the base 106, the intermating conical shapes of the bore 110 and the main body 130 provides a radial clamping force on the main body portion 130. This, in turn, provides a clamping force on the outer jacket 38 that is within the throughhole 140.
In the depicted example embodiment, the first clamp structure 104 receives the outer jacket 38 in a direction from the second end 134 to the first end 132 with the exposed fibers extending away from the first end 132 toward a piece of telecommunications device for splicing. In this manner, if the outer jacket 38 is pulled along a direction from the first end 132 toward the second end 134, away from the second end 134, the cable 22 is clamped even tighter due to the tapering interface between the main body 130 and the bore 110.
After the first clamp structures 104 have been inserted into the base 106, as noted above, the cover 108 may be used to limit removal of the first clamp structures 104 from the base 106. The portions of the base 106 that form the elongate grooves 126 and the elongate ridges 138 of the first clamp structure 104 are configured to provide spacing 142 around the top perimeter of the base 106 for receiving the cover 108. The cover 108 can be snap-fit to the base 106 via tabs 144 provided at a bottom side 146 of the cover 108, as shown in
Also, the bottom side 118 of the base 106 of the strain relief device 100 can be configured similar to the bottom side 146 of the cover 108 such that two strain relief devices 100 can be stacked on top of each other, as shown in
Regarding the clamping of the strength member 40 that is exposed after the outer jacket 38 has been stripped, the first clamp structure 104 defines a cutout 148 at the first end 132 of the main body 130. The cutout 148 is configured to accommodate a downwardly folded portion of the exposed strength member 40. After the strength member 40 is folded downwardly, the strength member 40 is folded rearwardly underneath the first clamp structure 104 as shown in
According to one example method of clamping the fiber optic cable, in order to facilitate the placement of the strength member 40 within the strain relief device 100, the portion of the strength member 40 that is exposed after the outer jacket 38 has been stripped is first folded downwardly and rearwardly underneath the first clamp structure 104. The portion of the strength member 40 that protrudes from the second end 134 of the main body 130 of the first clamp structure 104 after it has been folded is first inserted into the bore 110 and then the first clamp structure 104 is slidably placed within the bore 110, clamping the strength member 40 underneath thereof. And, as the first clamp structure 104 is further slid within the bore 110 of the base 106, the cable 22 gets clamped radially inwardly within the throughhole 140 of the first clamp structure 104.
Thus, according to the embodiments of the strain relief devices 24, 100 discussed above, the devices 24, 100 include a first structure that is moved with respect to a second structure to clamp a cable 22 in between the first structure and the second structure. A strength member 40 of the cable 22, after the outer jacket 38 of the cable 22 has been stripped and the strength member 40 has been exposed, can be folded back and clamped with the cable 22 against strain relief device, while optical fibers of the cable can continue to a piece of telecommunications equipment for splicing. The strain relief devices 24, 100 are configured such that farther the first structure is moved with respect to the second structure, the tighter the cable 22 and the strength member 40 get clamped to the strain relief device 24, 100.
Although in the foregoing description, terms such as “top”, “bottom”, “front”, “back”, “right”, “left”, “upper”, and “lower” may have been used for ease of description and illustration, no restriction is intended by such use of the terms. As discussed previously, the telecommunications equipment such as the strain relief devices and the fiber management trays described herein can be used in any orientation, depending upon the desired application.
From the foregoing detailed description, it will be evident that modifications and variations can be made in the devices or methods of the disclosure without departing from the spirit or scope of the inventive aspects.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2012/074547 | 12/5/2012 | WO | 00 | 6/19/2014 |
Number | Date | Country | |
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61577523 | Dec 2011 | US |