GB2580185A - A mechanical joint closure - Google Patents

Abstract

A tool-less mechanical joint closure 1, such as used in telecommunications, comprises a casing 3 having an entry/exit port (figure 1, 5) and a plug 7 for closing the entry/exit port (figure 1, 5). The casing comprises a base 9, a cover 11 and a dedicated cable clamp 13 independently operable from the cover 11. The plug 7 comprises a two-part plug including a cable retention part 19 configured for engagement by the cable clamp 13 and a cable sealing part 21 configured for engagement by the cover 11. There may be a plurality of channels (figure 6, 37) and furrows (figure 6, 34) in the plug 7. The base 9 and cover 11 may be hinged. The base 9 and clamp 13 may be connected by a live hinge. There may be clips 25 for securing at various positions. The sealing part 21 may have an outer layer of deformable material, such as an elastomeric material, to form a seal. The geometry of the closure 1 and the plug 7 may vary between embodiments.

Description

"A mechanical joint closure"

Introduction

This invention relates to a tool-less mechanical joint closure of the type commonly used in the telecommunications industry.

When splicing the ends of two cables together outdoors, it is important to ensure that the cable splice, or "joint", is protected from the elements. Heretofore, it is common practice for the cable splice to be housed in a mechanical joint closure. The mechanical joint closure provides sufficient protection against water and dirt ingress, thereby protecting the joint. Typically, a high level of protection against water ingress is necessary as the mechanical joint closure may be subjected to high levels of rainfall or in some cases may be buried underground in which case the mechanical joint closure may, at times, be submerged under. water.

PCT Patent Application Publication No. W02005/006513 in the name of Tyco Electronics Raychem NV, discloses a cable splice closure and method of installation therefor. This closure provides a good level of protection against water ingress. PCT Patent Application Publication No. W02005/002017, also in the name of Tyco Electronics Raychem NV discloses a cable splice closure that also may be used to provide an effective level of protection against water ingress. There is however a problem with the known offerings of cable splice closure. Typically, in order to achieve the desired level of water ingress protection, it is necessary to surround the cables with a gel-type seal before closing the casing around the cables and gel-type seal. However, this presents numerous problems.

First of all, it is difficult to judge the correct amount of gel-type seal to use in order to achieve an adequate seal. Too little, and the desired level of water ingress protection will not be achieved. Too much, and the cost of providing the seal becomes prohibitive. It is possible to provide pre-cut lengths of the gel-type seal however these are expensive. Secondly, the gel-type seal is another material that the technician must keep and carry with them in their inventory which is undesirable. Thirdly, once the casing is opened, the seal will have to be redone. -2 -

In addition to the foregoing, another problem with the existing offering is that once the casing is opened, the cables will no longer be held relative to the casing and the casing will have to be put down or stored while the technician works on the cable splice. This is inconvenient and cumbersome, particularly if the technician is working at height.

Furthermore, once outside the casing, the cable splice will be vulnerable and more susceptible to damage.

It is an object of the present invention to provide a mechanical joint closure that overcomes at least some of the above-identified problems with the existing offerings and offers a useful choice to the consumer.

Statements of Invention

According to the invention there is provided a tool-less mechanical joint closure comprising a casing having an entry/exit port and a plug for closing the entry/exit port of the casing; the casing comprising a base, a cover and a dedicated cable clamp independently operable from the cover; the plug comprising a two part plug including a cable retention part configured for engagement by the cable clamp and a cable sealing part configured for engagement by the cover, the cable retention part and the cable sealing part being arranged in series axially along the length of the plug with the cable retention part being located adjacent the outermost end of the plug relative to the interior of the casing and the cable sealing part being located adjacent the innermost end of the plug relative to the interior of the casing.

By having such a mechanical joint closure, the cables will still be held in a fixed relationship with the casing while the cover may be removed and the cables worked on inside the casing. In other words, the cover may be removed to expose a cable splice chamber that can be accessed without opening the cable clamp and disturbing the cable splice during maintenance. This provides greater protection to the cables and is less cumbersome for the technician to work on the cables. Furthermore, and importantly, by having the configuration of plug described, retention of the cables is not reliant on the force exerted by the casing on the cable sealing part. In other words, the functions of cable retention and cable sealing have been divided out. This has resulted in a -3 -significant improvement over the existing offerings as the seal material is no longer limited by physical characteristics necessary to adequately "grip" the cable through frictional resistance. More specifically, a softer, more pliable material that will form an effective seal may be used as the function of cable retention is dealt with elsewhere.

In one embodiment of the invention there is provided a tool-less mechanical joint closure in which the cable retention part comprises a plurality of elongate furrows, each furrow having a plurality of teeth dimensioned for engagement and retention of a cable therein.

In one embodiment of the invention there is provided a tool-less mechanical joint closure in which the cable sealing part comprises a plurality of elongate channels dimensioned for reception of a cable therein.

In one embodiment of the invention there is provided a tool-less mechanical joint closure in which the base and the cover are hingedly connected to each other.

In one embodiment of the invention there is provided a tool-less mechanical joint closure in which the base and the dedicated cable clamp are hingedly connected to each other.

In one embodiment of the invention there is provided a tool-less mechanical joint closure in which the base and the dedicated cable clamp are connected by way of a live hinge. This is seen as a particularly useful way of keeping the dedicated cable clamp and the base connected together.

In one embodiment of the invention there is provided a tool-less mechanical joint closure in which there is provided a gasket seal intermediate the base and the cover of the casing.

In one embodiment of the invention there is provided a tool-less mechanical joint closure in which there are provided a plurality of clips for securing the cover and the base in a closed configuration. -4 -

In one embodiment of the invention there is provided a tool-less mechanical joint closure in which there is provided a clip for securing the dedicated cable clamp and the base in a closed configuration.

In one embodiment of the invention there is provided a tool-less mechanical joint closure in which the clip is an over centre latch.

In one embodiment of the invention there is provided a tool-less mechanical joint closure in which the plug comprises a substantially rigid inner spine extending the length of the plug and, for the cable sealing part, an outer layer of resiliently deformable material. This is seen as a particularly simple construction of device that will be relatively simple and inexpensive to manufacture.

In one embodiment of the invention there is provided a tool-less mechanical joint closure in which the outer layer of resiliently deformable material is over-moulded onto the inner spine. This is seen as particularly advantageous. By over-moulding the outer later of resiliently deformable material onto the inner spine, there will automatically be an effective seal between the inner spine and the outer layer. Therefore, the only potential point for water ingress through the plug is around the cables between the cable and the outer layer and between the outer layer and the casing. As mentioned above, due to the fact that the cable retention action is performed elsewhere, the material used for the outer layer may be softer, more pliable that will provide an effective seal.

In one embodiment of the invention there is provided a tool-less mechanical joint closure in which the outer layer of resiliently deformable material is an elastomeric material. The resiliently deformable material will preferably be a soft rubber, elastic material that can stretch and return to it's original shape and that is, resilient against environmental impacts.

In one embodiment of the invention there is provided a tool-less mechanical joint closure in which the outer layer of resiliently deformable material is dimensioned to form a close fit in the casing thereby forming a seal with the cover and the base when the cover and the base are in a closed configuration. In this way, it will not be necessary to provide a wrap of gel-type sealant material. -5 -

In one embodiment of the invention there is provided a tool-less mechanical joint closure in which the inner spine comprises a hard thermoplastic material. The hard thermoplastic material must be UV stable and able to meet all environmental performance conditions during operation. The hard thermoplastic material may be, for example, polypropylene or a composite of polypropylene and glass fibre. This is seen as useful as it will be sufficiently hard wearing and robust to securely fasten the cable in position and prevent the cable being pulled out of the enclosure.

In one embodiment of the invention there is provided a tool-less mechanical joint closure in which the casing is constructed from a hard thermoplastic material. One substance that is seen as particularly useful for the casing would be polypropylene. This is seen as useful as the material is highly resistant to water ingress and therefore is particularly suitable for the present application.

In one embodiment of the invention there is provided a tool-less mechanical joint closure in which the channels are formed in the outer layer of resiliently deformable material and each channel is accessible through a corresponding elongate slit formed in the outer layer of resiliently deformable material. In this way, the cables may be inserted through the slit into the channel and the slit will "close over" once again after the cable has passed through into the channel. This will aid in providing a good seal between the cable and the outer layer of resiliently deformable material.

In one embodiment of the invention there is provided a tool-less mechanical joint closure in which there are provided a pair of inwardly depending, circumferentially extending partition walls inside the casing for location either side of the outer layer of resiliently deformable material. By having these walls, as the casing compresses the outer layer of resiliently deformable material, the walls will halt the spread of the outer layer in an axial direction along the casing, thereby compacting the outer layer into a smaller space and providing a more effective seal.

In one embodiment of the invention there is provided a tool-less mechanical joint closure in which the base and the plug are provided with complementary locators for alignment of the plug relative to the base. -6 -

In one embodiment of the invention there is provided a tool-less mechanical joint closure in which the cable retention part comprises a plurality of elongate furrows having different radial depths. In this way, a number of different diameter cables may be catered for.

In one embodiment of the invention there is provided a tool-less mechanical joint closure in which the cable sealing part comprises a plurality of elongate channels having different diameters. The channels can correspond to the furrows so that the channels are able to receive an appropriately sized cable and provide an effective seal therearound.

In one embodiment of the invention there is provided a tool-less mechanical joint closure in which the base is hingedly connected to the cover by way of hinge straps.

In one embodiment of the invention there is provided a tool-less mechanical joint closure in which the casing is an elongate casing and has an entry/exit port at each end of the casing, and in which there is provided a pair of plugs, one each of the entry/exit ports of the casing.

In one embodiment of the invention there is provided a tool-less mechanical joint closure in which the casing is substantially cuboid and there are provided a plurality of entry/exit ports arranged side by side along one face of the casing.

In one embodiment of the invention there is provided a tool-less mechanical joint closure in which the dedicated cable clamp comprises at least one inwardly depending tooth for engagement of the cable retention part of the plug. The tooth may be dimensioned to engage the cable as well, thereby providing a more effective grip on the cable. Ideally, the tooth would interlock with the cable retention part so that the cable is bent as it travels past the tooth.

In one embodiment of the invention there is provided a tool-less mechanical joint closure in which the cable retention part of the plug comprises a complementary tooth for engagement of the inwardly depending tooth of the dedicated cable clamp. -7 -

In one embodiment of the invention there is provided a tool-less mechanical joint closure in which there are provided a plurality of interchangeable plugs, each plug having a different configuration of furrows and channels to the other plugs. In this way, a technician may choose the configuration of plug that they require and use the most appropriate plug to suit the cable configuration.

Detailed Description of the Invention

The invention will now be more clearly understood from the following description of some embodiments thereof given by way of example only with reference to the accompanying drawings, in which:-Figure 1 is a perspective view of a tool-less mechanical joint closure according to the invention in a closed configuration; Figure 2 is a perspective view of a tool-less mechanical joint closure according to the invention in an open configuration but with the cable clamp engaged; Figure 3 is a perspective view of a tool-less mechanical joint closure according to the invention in an open configuration with the cable clamp disengaged; Figure 4 is a perspective view of a tool-less mechanical joint closure casing according to the invention; Figure 5 is a perspective view of a tool-less mechanical joint closure plug according to the invention; Figure 6 is a perspective view of a tool-less mechanical joint closure plug according to the invention without cables; Figure 7 is an exploded view of the tool-less mechanical joint closure plug of Figure 6; -8 -Figures 8(a) to 8(c) inclusive are sequential diagrammatic representations of a cable being inserted into the plug; Figures 9(a) to 9(f) inclusive are perspective views of alternative plugs for use in the tool-less mechanical joint closure, Figure 10 is a perspective view of a plug being located in the casing; Figure 11 is an end view of a tool-less mechanical joint closure and plug; Figure 12 is a perspective view of an alternative embodiment of tool-less mechanical joint closure according to the invention; Figure 13 is a perspective view of the tool-less mechanical joint closure of Figure 12 in an open configuration but with the cable clamps engaged; Figure 14 is a perspective view of the tool-less mechanical joint closure of Figure 12 in an open configuration with the cable clamps disengaged; Figure 15 is a perspective view of the tool-less mechanical joint closure casing of the alternative embodiment shown in Figure 12; Figure 16 is a perspective view of a third embodiment of tool-less mechanical joint closure according to the invention with the casing in a closed configuration; Figure 17 is a perspective view of the tool-less mechanical joint closure of Figure 16 with the casing in an open configuration but with the cable clamps engaged; Figure 18 is a perspective view of the tool-less mechanical joint closure of Figure 16 with the casing in an open configuration ready to engage a plug in one of the ports, -9 -Figure 19 is a perspective view of the tool-less mechanical joint closure of Figure 16 in an open configuration but with the plugs inserted and the cable clamps engaged; Figure 20 is a perspective view of the tool-less mechanical joint closure of Figure 16 in a closed configuration; Figure 21 is a perspective view of a fourth embodiment of tool-less mechanical joint closure according to the invention with the casing in a closed configuration; Figure 22 is a perspective view of the tool-less mechanical joint closure of Figure 21 with the casing in an open configuration; Figure 23 is a perspective view of a fifth embodiment of tool-less mechanical joint closure according to the invention with the casing in a closed configuration; Figure 24 is a perspective view of the tool-less mechanical joint closure of Figure 23 with the casing in an open configuration; and Figure 25 is an enlarged view of part of the tool-less mechanical joint closure of Figure 23 with a cassette being introduced into the casing.

Referring to Figures 1 to 4 inclusive, there is shown a tool-less mechanical joint closure, indicated generally by the reference numeral 1, comprising a casing 3 having an entry/exit port 5 and a plug 7 for closing the entry/exit port. The casing comprises a base 9, a cover 11 and a cable clamp 13 independently operable from the cover. The base 9 is hingedly connected to the cover 11 by way of hinge straps 15 and the base is hingedly connected to the cable clamp 13 by way of a live hinge joint 17. The plug 7 is a two part plug consisting of a cable retention part 19 and a cable sealing part 21, as will be described below with reference to Figures 5 to 9.

In use, a plurality of cables are inserted into the plug 7 and the plug is placed in the casing. Once the plug is located correctly in the casing, the cable clamp 13 is closed and a corresponding latch, in this case an over centre latch 23, is used to secure the cable -10 -clamp 13 in position. The cable clamp 13 engages the cable retention part 19 of the plug 7 thereby securing it in position relative to the casing 3. Once the plug is in position, the cover 11 is placed in engagement with the base 9 and a plurality of latches, in this case over centre latches 25, are closed to secure the cover to the base. A gasket seal 27 is positioned on the base to provide a watertight seal for the casing once the cover and the base are brought together. When the cover and the base are brought together and the plurality of over centre latches 25 are secured, the cable sealing part 21 of the plug 7 will prevent water ingress into the interior of the casing past the cables 29.

Referring now to Figures 5 to 7 inclusive, there is shown a plug 7 having a cable retention part 19 and a cable sealing part 21. Referring specifically to Figure 7, the plug 7 comprises a substantially rigid inner spine 31 extending the length of the plug and an outer layer 33 of resiliently deformable material. The outer layer of resiliently deformable material 33 is over-moulded directly onto the inner spine 31 and in this way, a seal is formed between the outer layer 33 and the inner spine 31.

Referring specifically to Figure 6, the cable retention part 19 comprises a plurality of elongate furrows 34 each having a plurality of teeth 35 operable to engage a cable 29 (as illustrated in Figure 5). Ideally, the teeth are dimensioned so that they will "dig in" to the surface covering of the cable 29. In other words, the teeth are spaced apart from each other a distance less than the maximum diameter of the cable to be engaged. The cable sealing part 21 comprises the resiliently deformable outer layer 33 with channels 37 for reception of cables therein. The channels 37 are accessed via elongate slots 39 formed in the outer layer 33.

Referring now to Figures 8(a) to 8 (c), there is illustrated the steps of placing a cable 29 into a plug 7. The cable 29 is first inserted into the cable retention part 19 of the plug by pushing the cable into the furrow 34. The teeth 35 will grip the outer surface of the cable 29. The channel 37 is opened by a user peeling open the channel 37 (as illustrated in Figure 8(a)) at the slot 39 and the cable 29 is fed into the slot (Figure 8(b)). Once the cable 29 is in the channel 37, the resiliently deformable material will close the slot once more, as illustrated in Figure 8(c). A range of blanking plugs (not shown) is available to seal unused cable entry ports where a cable is not installed.

In the embodiments shown in Figures 5 to 8 inclusive, there are four furrows 34 and four channels 37. Two of the furrows 34 are of a first size (20 pair gauge) and the other two furrows 34 are of a different, second size (5 pair gauge). The channels 37 correspond to the sizes of the furrows 34. However, more or less furrows 34 of different sizes or similar sizes may be provided if desired, as will be understood by reference to Figures 9(a) to 9(f). In Figure 9(a), there are seven furrows and channels in total, one 5 pair gauge furrow/channel and the remainder are smaller, narrower furrows. In Figure 9(b), there are three furrows and three channels, all of which are dimensioned to fit 10 pair gauge cable. In Figure 9(c), there are again three furrows and three channels, however, all of which are dimensioned to fit 20 pair gauge cable. In Figure 9(d), there are again three furrows and three channels, however, in this case, all of the furrows 34 and their corresponding channels are dimensioned to fit cables of different diameters. In Figure 9(e), there is shown an embodiment of plug 7 similar to that illustrated in Figures 5 to 8 having four furrows and four channels, two furrow/channel combinations in one size and the other two furrow/channel combinations in another size. Finally, in Figure 9(f), there are again four furrows and four channels, however, all of the furrows and channels are the same size. These are merely exemplary of the range on offer and other combinations will be readily envisaged.

Referring to Figures 10 and 11, there is shown an expanded view and an end view, respectively of the plug and the casing. In Figure 10, it can be seen that the plug 7 has a locator spigot 41 and the casing has a complementary locator receiver 43. Once the locator spigot 41 is located in the locator receiver 43, the operator knows that the plug and the casing are correctly aligned and may be closed together to effectively seal the casing.

Referring now to Figures 12 to 15 inclusive, there is shown a second embodiment of mechanical joint enclosure according to the invention, indicated generally by the reference numeral 51, where like parts have been given the same reference numeral as before. The mechanical joint enclosure 51 differs from the mechanical joint enclosure 1 in that the mechanical joint enclosure is open at both ends and there is provided a pair of plugs 7, one for either end of the mechanical joint enclosure, and a pair of cable clamps 13. The operation of the cable clamps, the plugs and the mechanical joint enclosure are -12 -essentially the same as described above with the difference that a plug and cables are inserted into the opposite ends of the mechanical joint enclosure 51 Referring now to Figures 16 to 20 inclusive, there is shown a third embodiment of mechanical joint enclosure according to the invention, indicated generally by the reference numeral 61, where like parts have been given the same reference numeral as before. The mechanical joint enclosure 61 differs from the mechanical joint enclosures 1 and 51 in that the casing 63 is substantially cuboid in shape as opposed to the substantially cylindrically-shaped casings 3 of the previous embodiments. Furthermore, the casing 63 has a plurality of entry/exit ports 5 arranged side by side along one side of the casing 63. The base 65 of the casing is attached to the cover 67 by hinge joint 69. There are further provided four separate cable clamps 71, one for each port 5 of the casing. A plurality of casing clamps 73 are provided to maintain the cover and the base of the casing in a fixed relationship with respect to each other. A gasket seal 75 around the periphery of the casing provides a seal between the interior and the exterior. In the embodiment shown, there are ports only located on one side however it will be understood that there may be ports on an opposing or other face as well if desired.

In the embodiments shown, the outer layer of resiliently deformable material of the plug is ideally an elastomeric material, the casing is preferably constructed from polypropylene and the spine is preferably constructed from a composite hard thermoplastic material, such as, but not limited to, a composite of polypropylene and glass fibre.

Referring to Figures 2, 4, 13 and 15, there are provided a pair of inwardly depending, circumferentially extending partition walls 81 inside the casing for location either side of the outer layer of resiliently deformable material. By having such partition walls, as the casing compresses the outer layer of resiliently deformable material, the walls will halt the spread of the outer layer in an axial direction along the casing, thereby compacting the outer layer into a smaller space and providing a more effective seal with the casing.

It can be further seen from Figures 3, 4, 10, 14 and 15 that the dedicated cable clamp comprises at least one inwardly depending tooth 83 for engagement of the cable retention part of the plug. The tooth may be dimensioned to engage the cable as well, -13 -thereby providing a more effective grip on the cable. Ideally, the tooth would interlock with the cable retention part so that the cable is bent as it travels past the tooth Referring now to Figures 21 and 22, there is shown a fourth embodiment of tool-less mechanical joint closure, indicated generally by the reference numeral 91, where like parts have been given the same reference numeral as before. The mechanical joint closure is a so-called "in-line" mechanical joint closure similar to the embodiment of mechanical joint closure shown in Figures 12 to 15 inclusive in that it has an entry/exit port at each end of the casing. The mechanical joint closure 91 of Figures 21 and 22 differs from the mechanical joint closure of Figures 12 to 15 inclusive in that the mechanical joint closure 91 of Figures 21 and 22 has a casing 93 with a pair of entry exit ports 5 at each end of the casing 93 and a pair of cable clamps, one for each of the entry exit ports 5, at each end of the casing 93.

Referring now to Figures 23 to 25 inclusive, there is shown a fifth embodiment of tool-less mechanical joint closure, indicated generally by the reference numeral 101, where like parts have been given the same reference numeral as before. The tool-less mechanical joint closure 101 is a so-called "end cap" mechanical joint closure similar to the embodiment of mechanical joint closure shown in Figures 1 to 11 and 16 to 20 inclusive in that it has an entry/exit port at only one end of the casing. The mechanical joint closure 101 of Figures 23 to 25 differs from the mechanical joint closure of Figures 16 to 20 inclusive in that the mechanical joint closure 101 of Figures 23 to 25 also has four entry/exit ports 5 however the entry/exit ports, rather than being arranged in a row, are arranged in a matrix of two columns and two rows. Furthermore, the casing 103 of the mechanical joint closure 101 further comprises a cassette 105 which is releasably detachable from the casing. The cassette 105 receives the plurality of plugs (not shown) and there are provided a plurality of cable clamps 13 operable to hold the cable in a fixed relationship with respect to the cassette. The cassette 105 has a groove 107 formed therein for engagement by an upstanding inwardly depending wall 109 on the casing 109. The wall 109 and the groove 107 together ad to retain the cassette in the casing 103.

In use, the operator will insert plugs into the entry/exit ports 5 and retain those plugs in the cassette using the cable clamps 13. The cassette will then be inserted into the -14 -casing 103 by aligning the wall 109 with the groove. The two parts of the casing will then be brought together and the over centre latches 25 are secured, thereby holding the cassette in place and sealing the casing.

It will be understood that various modifications may be made to the embodiments hereinbefore described without departing from the scope of the appended claims. Throughout the specification, the mechanical joint closure is described as being a "tool-less" mechanical joint closure. By this, what is meant is that the mechanical joint closure does not require any tools such as a screwdriver or an alien (hex) key to open or close fasteners of the mechanical joint closure. Instead, the mechanical joint closure can be opened and closed by an operator using only their hands.

In this specification the terms "comprise, comprises, comprised and comprising" and the terms "include, includes, included and including" are all deemed totally interchangeable and should be afforded the widest possible interpretation.

The invention is not limited to the embodiments hereinbefore described but may be varied in both construction and detail within the scope of the appended claims.