CA2314812A1 - Non-silicone sealant for universal indoor-outdoor applications and insulation-displacement cross connector - Google Patents
Non-silicone sealant for universal indoor-outdoor applications and insulation-displacement cross connector Download PDFInfo
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- CA2314812A1 CA2314812A1 CA 2314812 CA2314812A CA2314812A1 CA 2314812 A1 CA2314812 A1 CA 2314812A1 CA 2314812 CA2314812 CA 2314812 CA 2314812 A CA2314812 A CA 2314812A CA 2314812 A1 CA2314812 A1 CA 2314812A1
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Abstract
The present invention discloses an environmentally sealed universal connector for electrical applications. The universal connector includes a support plate, a cover plate, contacts, and a universal sealant applicable for both indoor and outdoor use. The preferred universal sealant includes an isocyanate, a polybutadiene resin, and a diluent that is inert to reaction with isocyanate and polybutadiene resin. Hydrocinnamic acid can also be included. The universal sealant surrounds and seals the electrical contacts contained between the support plate and the cover plate.
Description
PATENT
Background The present invention relates to an electrical connector and a non-silicone sealant for the connector for indoor/outdoor use, in particular for telephone connectors.
It is desirable to protect connectors and the electrical contacts within the connectors from environmental influences and other adverse conditions occurring both indoors and outdoors. Even though the electrical contacts and other equipment may be contained in a protective housing, such arrangements are still prone to environmental contamination and corrosion.
Connectors for outdoor use suffer environmental effects such as corrosion, moisture, dirt, and heat.
Connectors for indoor use suffer from similar environmental effects but also are likely to suffer from electrical interference and migration of insulation as well as impact from the surroundings.
There are several known methods of protecting electrical conductors, and more particularly, splices between electrical conductors. Such methods include the use, of a wide variety of designs of connectors in combination with various insulators ~or sealants. Some insulators are pre-shaped members similar to the shape of the surface to be protected while others are low viscosity fluids or gels applied to the surface. Typical insulations include silicone gels, greases, or polyethylene surrounding the electrical conductors and the splices.
Components manufactured for outdoor applications are frequently environmentally sealed using a two-component silicone gel. The potential for migration and interference with electronic components in the indoor environment makes the silicone sealant unsuitable for indoor application.
Though gels have a three-dimensional network resulting in finite elongation properties that tend to maintain the gel in contact with the substrate being protected, there are numerous drawbacks to the gels currently being used in this art. Certain gels, especially when placed under an external load, tend to pull somewhat away from the substrate or leave voids over time, particularly as dynamic changes occur in both the substrate and the gel. These changes are a result of material creep, changes in volume due to temperature exposure, and other factors. Silicone compositions have a relatively high water permeability and tend to have low adhesion properties to common solid dielectric materials, such as polyethylene and polycarbonate.
Improvements for the transition to the indoor environment have been attempted using grease-based sealants. A drawback associated with greases is that their viscosity decreases as they are heated causing them to flow. Another typical problem with greases is that they lack virtually any three-dimensional structure and hence show no elongation. Greases tend to flow from the area that they are intended to environmentally protect and eventually to leak out of containment, especially when subjected to external forces. While greases are particularly effective at repelling water and tend.to be used in indoor application, their tendency to flow and leak due to their viscous nature creates a shortcoming. The value of grease sealants is further limited because a connector sealed with grease is not re-enterable, nor does it create an interface by sticking to the metal contacts.
These and other drawbacks are present with other sealants known in the art.
For example, polyethylene sealants are unlikely to provide sufficient uniformity and may fail when subjected to temperature cycling. Liquid butyl rubber and other substances tested for usefulness show similar behavior. Polyurethanes and polyolefinic block copolymers have also been tried. Polyurethane compositions containing olefinic unsaturates have relatively low heat stability that tends to limit their use when they are subjected to elevated temperature for extended periods of time. Polyurethane and PET sealants also tend to stress crack base materials such as polycarbonate.
Although a wide variety of compositions have been tried as sealants for indoor or outdoor use, there remains a need for a sealant that is universally useful such that it can be used both indoors and.outdoors while avoiding the drawbacks mentioned above.
In order to provide a connector and sealant for both indoor and outdoor application, there is a need for a soft material with low modulus in order to facilitate wire termination. There is a need for a material where the softness is maintained at extreme temperatures, such as between -40 degrees C and 80 degrees C. Sufficient cohesive integrity is needed over this temperature range such that the material does not leak out of the connector. A common problem associated with sealants is the short pot life of the materials once prepared. There is a need for a composition with a pot life of suffcient length to allow the material to remain workable for a reasonable time to facilitate machine dispensing and ease of manufacturing. There is a need for a composition that will not chemically attack or stress crack the housing material. A need exists for a universal connector utilizing the same sealant for both indoor and outdoor applications.
It is an object of the invention to eliminate the above-noted drawbacks and to provide an electrical connector and sealant for use with an indoor/outdoor connector to meet the stated needs and others. The sealant should be easily reenterable and should reheal after reentry.
Summary of the Invention The present invention discloses an environmentally sealed universal connector for electrical applications. One embodiment includes an electrical connector for connecting telecommunication wires wherein the connector has a housing with a cavity therein. A plurality of insulation displacement contacts are disposed in the cavity, each contact having a first pair of blades on a first end for receiving an insulated wire between them and a second pair of blades on a second end for received another insulated wire between them. The blades serve to strip insulation from the wires and establish continuity between the wires. The housing includes an access hole adjacent each pair of blades to allow for inserting the wires. A sealant fills the cavity to insulate the contacts and the wires. The sealant is an isocyanate, a polybutadiene resin, and a diluent that is inert to reaction with isocyanate and polybutadiene resin.
A preferred embodiment of the universal connector includes a support plate, a cover plate, as well as the plurality of contacts. The support plate has a top surface, a bottom surface, and outer edges. A plwality of transverse protrusions extends along the support plate such that the protrusions define a plurality of slots along the outer edges. The support plate has a plurality of ridges extending from the top surface with the ridges running in a transverse direction between outer edges to partially surround the protrusions such that grooves are bound between adjacent ridges.
The cover plate, which has outer rims, has a plwality of transverse complementary protrusions.
The complementary protrusions define a plurality of complementary slots along the outer rims with the complementary slots generally aligning with the slots of the support plate in the assembled connector. A plurality of contacts generally align within the grooves, and a universal sealant, suitable for both indoor and outdoor use, fills the grooves substantially surrounding the contacts. The universal sealant acts to connect the cover plate to the top surface of the support plate as well as to environmentally protect the contacts.
By inserting wires into any pair of axially-opposed slots, the wires come into communication with the contact and complete the circuit. The number of contacts available in the environmentally sealed universal connector is increased substantially by arranging the bottom surface of the support plate similar to the top surface. This is achieved through the addition of a plurality of ridges extending transversely between outer edges on the bottom surface of the support plate. As on the top surface, the ridges on the bottom surface partially surround the protrusions such that grooves are bound between adjacent ridges. The ridges on the bottom surface are longitudinally staggered relative to the ridges on the top surface. Contacts generally align within the grooves and are substantially surrounded by the universal sealant. By staggering the ridges on the top surface relative to the bottom surface, the number of slots in communication with contacts is virtually doubled. A second cover plate connects to the bottom surface of the support plate with the universal sealant. The second cover plate has outer rims and transverse complementary protrusions, the protrusions defining a plurality of complementary slots along the outer rim that generally align with the slots of the support plate.
In a preferred embodiment, a plurality of short ribs are disposed between adjacent ridges, the short ribs extending partially through the grooves. The contacts include longitudinal indentions generally corresponding to the short rib such that, when the contacts are disposed within the grooves, motion of the contacts is partially constrained by the short ribs. Each contact is suspended from the short rib in the groove such that the groove is divided into an upper and lower space. In surrounding the contact, the universal sealant substantially fills the upper and lower space.
A preferred sealant of the invention is a non-silicone sealant suitable for use indoors as well as outdoors. As discussed above, one such universal sealant composition includes isocyanate, polybutadiene resin, and diluent that is inert to reaction with isocyanate and polybutadiene resin.
Hydrocinnamic acid can also be included. For the isocyanate, an aliphatic diisocyanate is preferred, in particular, one of molecular weight greater than 500.
The universal sealant of the invention preferably contains the isocyanate in an amount from 7 percent by weight to 16 percent by weight of the universal sealant, and the polybutadiene resin in an amount from 25 percent by weight to 54 percent by weight of the universal sealant. When hydrocinnamic acid is added, the hydrocinnamic acid is preferably in an amount from 0.5 percent by weight to 3 percent by weight of the universal sealant. The remainder of the universal sealant is largely the non-reactive diluent, such as heavy naphthenic distillates.
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 invention as claimed.
The following drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the invention and, together with the description, serve to explain the principles of the invention.
Brief Description of the Drawings Figure 1 is a perspective exploded view of pans of the connector of a preferred embodiment of the invention with dashed lines indicating how the components of the connector are assembled.
I Figure 2 is an enlarged exploded view of a portion of the connector of Figure 1.
Figure 3 is an enlarged plan view of a portion of the support plate.of the connector of Figure 1., with contacts assembled.
Figure 4 is a section view of a portion of the support plate taken along the line 3-3 of Figure 2.
Detailed Description of the Invention The disclosed invention includes an apparatus and composition useful for sealing and protecting telephone lines or other electrical applications at the terminal.
The absence of a silicon-based sealant makes the universal connector suitable for indoor applications in close proximity to active electronic components. The universal sealant of the invention is also effective for outdoor applications. This eliminates the need for two distinct connector products for indoor and outdoor use. The apparatus of the invention includes universal connector 1 as shown in Fig. 1 providing multiple contact points for incoming lines. When assembled along the dashed lines as shown in Fig.
l, support plate 2 connects to cover plate 3 with contacts 4 sandwiched between the support plate and cover plate. Support plate 2 and cover plate 3 are formed from an inert material such as polycarbonate, a preferred embodiment being the commercially available material under the trade name Lexan.
Support plate 2 has top surface 5 and outer edges 6. Outer edges 6 include protrusions 7 extending transversely from the support plate such that the protrusions define slots 8. The slots 8, bound by adjacent protrusions, are of sufficient width to receive an electrical wire, such as a standard insulated wire for telephone connectors.
Ridges 9 are located on top surface 5 of support plate 2. Ridges 9 run in a transverse direction across the support plate between outer edges 6 and partially around protrusions 7 such that grooves 20 are bound between adjacent ridges. Ridges 9 can be a single height or multiple heights, in order to conform to the inside surface of cover plate 3. Figs. 1 and 3 demonstrate ridge 9 as including a 'standing rib 10 that extends the height of lower ridge 70. Lower ridge 70 extends to partially surround the protrusion of the universal connector. The height of standing rib 10 is such that cover plate 3, when assembled, rests on the standing ribs 10. In a preferred embodiment, the inside surface (not shown) of cover plate 3 includes indentations generally corresponding to the shape of the standing ribs 10, thus increasing the contact area between the standing ribs 10 and the cover 3.
Another embodiment, particularly useful when the ridge 9 is of uniform height, includes a flat inside . HE0077 surface of the cover plate 3 that contacts the support plate 2. Yet another alternate includes other configurations for mating with the standing rib 10 or ridge 9.
The connector 1, without sealant, is secured in any way traditional in the art, the preferred method including sonic welding. Sonic welding allows the polycarbonate base material of the support plate 2 to link to the cover plate 3 with the contacts 4 in place.
Sonic welding is used to attach the cover plate 3 to the support plate 2 prior to the introduction of the universal sealant. As the polycarbonate material of the cover plate 3 and the material of the standing ribs 10 integrally bond into a seamless material with sonic welding, close contact and increased contact area ensure a strong bond.
The support plate and cover plate of a preferred embodiment also include gates 60 and 63, respectively, at each end. Cover plate gate 63 includes female connector 62 while support plate gate 60 includes corresponding male connector 61. Prior to sonic welding, the cover plate 3 and support plate,2 are held together by connecting the female connector 62 to the corresponding male connector 61.
A short rib 11 extends partially through the groove 20 (Fig. 1 and 3), the short rib 11 being of a height less than standing rib 10. Thus, each groove 20 is bordered by two adjacent ridges 9 with the short rib 11 protruding partially through groove 20. When the universal connector is assembled, contacts 4 generally align within grooves 20. Each contact 4 is preferably a relatively thin, flexible, conductive metal substantially similar.in shape to the' groove 20, preferably with indentions 40 generally corresponding to short rib 11 such that motion in the direction of the length of the support plate 2 is constrained by the short rib 11 and the standing rib 10.
While indention 40 generally corresponds to the shape of .short rib 11, indention 40 is of such a depth that the contact 4 is suspended in groove 20 as opposed to resting at the bottom of the groove. As short ribs 11 do not extend to the same height as standing ribs .10, the short ribs 11 and at least a substantial portion of the contact 4 do not touch the cover plate 3. Thus, the contact 4 suspended from the short rib 11 in the groove 20 acts to divide the groove 20 generally into upper space 21 and lower space 22. In surrounding the contact 4, the universal sealant substantially fills the upper and lower spaces.
Contacts 4 have first end 41 and second end 42. Each end is pronged such that the first end 41 has a first prong 45 and a second prong 46. Likewise, second end 42 has a first prong 45 and a second prong 46. The contact 4 readily permits connection or disconnection of a first insulated conductor to a second insulated conductor, such as in a conventional telephone circuit wire connector. The prongs 45, 46, being of a flexible material, can be pushed apart in the longitudinal direction of the support plate. -During installation, the installer inserts a wire into a desired slot 8 in the assembled connector 1 in a direction perpendicular to the longitudinal axis of the support plate 2. The wire pushes through any sealant that is present until reaching the contact 4. As the wire is forced into the base of the slot 8, the wire presses against the contact 4 forcing the prongs 45,46 of the contact 4 to flex providing necessary space for the wire. The prongs 45,46 also act as a blade by cutting through any coating on the wire such that the contact 4 securely touches the wire.
Excess wire extending beyond the universal connector can be trimmed away. Another wire is inserted in the opposite slot 8 placing contact 4 in communication with this second wire. The circuit between the two wires in then complete.
To efficiently increase the number of contacts 4 available on the connector 1, the bottom surface of the support plate 2 also has grooves 20 for receiving contacts 4.
As best seen in Fig. 3, the standing ribs 11 on the bottom surface are staggered relative to the standing ribs 11 on the top surface such that the number of slots 8 and thus contacts possible for the given length of the support plate is virtually doubled. .
A preferred embodiment for assembling the connector includes adding the sealant 50 to distribute evenly within each groove 20. The cover plate 3 of the preferred embodiment has holes 33, with at least one hole allowing access to each groove 20. During assembly, the contacts 4 are placed into their respective grooves 20 and the cover plate 3 is attached to the support plate 2. The sealant 50, in a pre-measured quantity, is then injected through holes 33 in the cover plate 3 to fill . HE0077 the grooves 20 and surround the contacts 4. Small quantities of the sealant are used, with 0.06 grams being prefenred.
The universal sealant material of the current invention exhibits multiple desirable characteristics. This material is environmentally stable in both indoor and outdoor applications, thus avoiding the common difficulty of requiring different sealants for indoor and outdoor usage. The material allows for rehealability so that reworking is possible. The material is also inert to silicon and polycarbonate. The gel is hydrophobic or moisture insensitive.
It can be seen that proper encapsulation of the contacts 4 and/or connectors 1 requires penetration of the insulating material into the highly intricate grooves and spaces in order to fully protect the contacts and connector. The sealant 50 of the current invention exhibits low viscosity suitable for conforming to such intricate spaces while curing to a stable compound that remains in place. In a termination block where multiple wires are connecting to respective contacts, the close proximity of the wires can create electronic noise or produce an electrical short circuit within the termination block. The universal sealant of the invention is also electrically insulating such that interference is minimized or eliminated.
The sealant of the invention is a two-part mixture of isocyanate with polybutadiene rubber, such as 4441 Gella Reenterable Encapsulating Compound distributed by 3M. This composition has been used in the prior art for encapsulating printed circuit board. Applicant has discovered that this sealant has a unique combination of properties useful in particular with electrical connectors. The composition is heat stable and can be used for sealing in locations subject to elevated temperatures for extended periods. Not only does the material show low water permeability, thus reducing the possibility of corrosion, but it also shows low oil permeability, waking it useful in applications where contact with oil is possible. The universal sealant is also an effective shock absorbing and insulating material.
The preferred composition is distributed as a two-part mixture, Part A and Part B, that are non-reactive until combined. Part A contains an isocyanate, preferably aliphatic diisocyanate. Part B is a polybutadiene resin. Part A and Part B both contain a non-reactive diluent base material of heavy naphthenic distillates. Part A also can contain a quantity of hydrocinnamic acid. The two-part liquid composition is prepared by mixing the ingredients, which then slowly react together. The composition of the invention has a suitable pot life in that the mixture remains viscous for a sufl;icient amount of time to allow pouring into the connector for encapsulating the components of the connector. Off ratio blending was also tested to evaluate modulus and other characteristics of the resulting blend. Preferred embodiments include mixtures of Part A and Part B of 4441 Gella in the range from 1 A: l B to 1.75A:1 B.
To cure the sealant, the universal connector with the sealant added is baked at 65 degrees C
for ten to twenty minutes. If baking is not desired, the sealant is self curing at room temperature over a longer period of time. Higher temperatures of baking reduce the time for curing. The preferred temperature for baking is 65 degrees C as the baked universal connector with sealant can be readily handled by personnel after baking and the time required to cure is optimized.
. Positive results were obtained when testing the universal sealant with the connector for various qualities. Leakage testing included sealing the composition in the connector and curing.
The sealed connector was placed on an indicator paper in an oven at 80 degrees C to observe any leakage. No leakage was observed for the composition of the invention. Tests performed to evaluate stress included bending the component for constant stress over the entire length of the connector side to test the stress corrosion of the plastic materials with the universal sealant. After curing, the universal sealant is generally inert and chemical attack to the polycarbonate material is not expected.
For testing purposes, uncured universal sealant was used to provide an aggressive environment. No cracking was observed using the universal sealant with polycarbonate material.
A thirty day salt fog test was also successfully completed, as was a temperature-humidity cycling test.
I From the foregoing it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth, together with other advantages that are obvious and that are inherent to the apparatus and structure.
l0 It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.
Because many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.
For example, an alternate embodiment would include pre-curing the gel with the contacts in a form corresponding to the shape of tk~e connector. Likewise, extenders and plasticizers can be added to the gel. The gel can contain moisture scavengers, antioxidants, fillers, pigments, tackifier, and fungicides.
An alternate embodiment of the contacts includes a slit through the contact generally aligning with the short rib. The contact is then placed over the short rib.
This is particularly useful if the sealant is pre-cured before assembly.
The universal connector can be jacketed with an external non-conductive protective jacket when extra protection from elements, interference or shock is desirable. The universal sealant of the invention is nonreactive with silicone or greases allowing such sealants to be used in near proximity, such as in securing a jacket.
The universal sealants can also be used to environmentally protect other designs of electrical connectors or the like.
Background The present invention relates to an electrical connector and a non-silicone sealant for the connector for indoor/outdoor use, in particular for telephone connectors.
It is desirable to protect connectors and the electrical contacts within the connectors from environmental influences and other adverse conditions occurring both indoors and outdoors. Even though the electrical contacts and other equipment may be contained in a protective housing, such arrangements are still prone to environmental contamination and corrosion.
Connectors for outdoor use suffer environmental effects such as corrosion, moisture, dirt, and heat.
Connectors for indoor use suffer from similar environmental effects but also are likely to suffer from electrical interference and migration of insulation as well as impact from the surroundings.
There are several known methods of protecting electrical conductors, and more particularly, splices between electrical conductors. Such methods include the use, of a wide variety of designs of connectors in combination with various insulators ~or sealants. Some insulators are pre-shaped members similar to the shape of the surface to be protected while others are low viscosity fluids or gels applied to the surface. Typical insulations include silicone gels, greases, or polyethylene surrounding the electrical conductors and the splices.
Components manufactured for outdoor applications are frequently environmentally sealed using a two-component silicone gel. The potential for migration and interference with electronic components in the indoor environment makes the silicone sealant unsuitable for indoor application.
Though gels have a three-dimensional network resulting in finite elongation properties that tend to maintain the gel in contact with the substrate being protected, there are numerous drawbacks to the gels currently being used in this art. Certain gels, especially when placed under an external load, tend to pull somewhat away from the substrate or leave voids over time, particularly as dynamic changes occur in both the substrate and the gel. These changes are a result of material creep, changes in volume due to temperature exposure, and other factors. Silicone compositions have a relatively high water permeability and tend to have low adhesion properties to common solid dielectric materials, such as polyethylene and polycarbonate.
Improvements for the transition to the indoor environment have been attempted using grease-based sealants. A drawback associated with greases is that their viscosity decreases as they are heated causing them to flow. Another typical problem with greases is that they lack virtually any three-dimensional structure and hence show no elongation. Greases tend to flow from the area that they are intended to environmentally protect and eventually to leak out of containment, especially when subjected to external forces. While greases are particularly effective at repelling water and tend.to be used in indoor application, their tendency to flow and leak due to their viscous nature creates a shortcoming. The value of grease sealants is further limited because a connector sealed with grease is not re-enterable, nor does it create an interface by sticking to the metal contacts.
These and other drawbacks are present with other sealants known in the art.
For example, polyethylene sealants are unlikely to provide sufficient uniformity and may fail when subjected to temperature cycling. Liquid butyl rubber and other substances tested for usefulness show similar behavior. Polyurethanes and polyolefinic block copolymers have also been tried. Polyurethane compositions containing olefinic unsaturates have relatively low heat stability that tends to limit their use when they are subjected to elevated temperature for extended periods of time. Polyurethane and PET sealants also tend to stress crack base materials such as polycarbonate.
Although a wide variety of compositions have been tried as sealants for indoor or outdoor use, there remains a need for a sealant that is universally useful such that it can be used both indoors and.outdoors while avoiding the drawbacks mentioned above.
In order to provide a connector and sealant for both indoor and outdoor application, there is a need for a soft material with low modulus in order to facilitate wire termination. There is a need for a material where the softness is maintained at extreme temperatures, such as between -40 degrees C and 80 degrees C. Sufficient cohesive integrity is needed over this temperature range such that the material does not leak out of the connector. A common problem associated with sealants is the short pot life of the materials once prepared. There is a need for a composition with a pot life of suffcient length to allow the material to remain workable for a reasonable time to facilitate machine dispensing and ease of manufacturing. There is a need for a composition that will not chemically attack or stress crack the housing material. A need exists for a universal connector utilizing the same sealant for both indoor and outdoor applications.
It is an object of the invention to eliminate the above-noted drawbacks and to provide an electrical connector and sealant for use with an indoor/outdoor connector to meet the stated needs and others. The sealant should be easily reenterable and should reheal after reentry.
Summary of the Invention The present invention discloses an environmentally sealed universal connector for electrical applications. One embodiment includes an electrical connector for connecting telecommunication wires wherein the connector has a housing with a cavity therein. A plurality of insulation displacement contacts are disposed in the cavity, each contact having a first pair of blades on a first end for receiving an insulated wire between them and a second pair of blades on a second end for received another insulated wire between them. The blades serve to strip insulation from the wires and establish continuity between the wires. The housing includes an access hole adjacent each pair of blades to allow for inserting the wires. A sealant fills the cavity to insulate the contacts and the wires. The sealant is an isocyanate, a polybutadiene resin, and a diluent that is inert to reaction with isocyanate and polybutadiene resin.
A preferred embodiment of the universal connector includes a support plate, a cover plate, as well as the plurality of contacts. The support plate has a top surface, a bottom surface, and outer edges. A plwality of transverse protrusions extends along the support plate such that the protrusions define a plurality of slots along the outer edges. The support plate has a plurality of ridges extending from the top surface with the ridges running in a transverse direction between outer edges to partially surround the protrusions such that grooves are bound between adjacent ridges.
The cover plate, which has outer rims, has a plwality of transverse complementary protrusions.
The complementary protrusions define a plurality of complementary slots along the outer rims with the complementary slots generally aligning with the slots of the support plate in the assembled connector. A plurality of contacts generally align within the grooves, and a universal sealant, suitable for both indoor and outdoor use, fills the grooves substantially surrounding the contacts. The universal sealant acts to connect the cover plate to the top surface of the support plate as well as to environmentally protect the contacts.
By inserting wires into any pair of axially-opposed slots, the wires come into communication with the contact and complete the circuit. The number of contacts available in the environmentally sealed universal connector is increased substantially by arranging the bottom surface of the support plate similar to the top surface. This is achieved through the addition of a plurality of ridges extending transversely between outer edges on the bottom surface of the support plate. As on the top surface, the ridges on the bottom surface partially surround the protrusions such that grooves are bound between adjacent ridges. The ridges on the bottom surface are longitudinally staggered relative to the ridges on the top surface. Contacts generally align within the grooves and are substantially surrounded by the universal sealant. By staggering the ridges on the top surface relative to the bottom surface, the number of slots in communication with contacts is virtually doubled. A second cover plate connects to the bottom surface of the support plate with the universal sealant. The second cover plate has outer rims and transverse complementary protrusions, the protrusions defining a plurality of complementary slots along the outer rim that generally align with the slots of the support plate.
In a preferred embodiment, a plurality of short ribs are disposed between adjacent ridges, the short ribs extending partially through the grooves. The contacts include longitudinal indentions generally corresponding to the short rib such that, when the contacts are disposed within the grooves, motion of the contacts is partially constrained by the short ribs. Each contact is suspended from the short rib in the groove such that the groove is divided into an upper and lower space. In surrounding the contact, the universal sealant substantially fills the upper and lower space.
A preferred sealant of the invention is a non-silicone sealant suitable for use indoors as well as outdoors. As discussed above, one such universal sealant composition includes isocyanate, polybutadiene resin, and diluent that is inert to reaction with isocyanate and polybutadiene resin.
Hydrocinnamic acid can also be included. For the isocyanate, an aliphatic diisocyanate is preferred, in particular, one of molecular weight greater than 500.
The universal sealant of the invention preferably contains the isocyanate in an amount from 7 percent by weight to 16 percent by weight of the universal sealant, and the polybutadiene resin in an amount from 25 percent by weight to 54 percent by weight of the universal sealant. When hydrocinnamic acid is added, the hydrocinnamic acid is preferably in an amount from 0.5 percent by weight to 3 percent by weight of the universal sealant. The remainder of the universal sealant is largely the non-reactive diluent, such as heavy naphthenic distillates.
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 invention as claimed.
The following drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the invention and, together with the description, serve to explain the principles of the invention.
Brief Description of the Drawings Figure 1 is a perspective exploded view of pans of the connector of a preferred embodiment of the invention with dashed lines indicating how the components of the connector are assembled.
I Figure 2 is an enlarged exploded view of a portion of the connector of Figure 1.
Figure 3 is an enlarged plan view of a portion of the support plate.of the connector of Figure 1., with contacts assembled.
Figure 4 is a section view of a portion of the support plate taken along the line 3-3 of Figure 2.
Detailed Description of the Invention The disclosed invention includes an apparatus and composition useful for sealing and protecting telephone lines or other electrical applications at the terminal.
The absence of a silicon-based sealant makes the universal connector suitable for indoor applications in close proximity to active electronic components. The universal sealant of the invention is also effective for outdoor applications. This eliminates the need for two distinct connector products for indoor and outdoor use. The apparatus of the invention includes universal connector 1 as shown in Fig. 1 providing multiple contact points for incoming lines. When assembled along the dashed lines as shown in Fig.
l, support plate 2 connects to cover plate 3 with contacts 4 sandwiched between the support plate and cover plate. Support plate 2 and cover plate 3 are formed from an inert material such as polycarbonate, a preferred embodiment being the commercially available material under the trade name Lexan.
Support plate 2 has top surface 5 and outer edges 6. Outer edges 6 include protrusions 7 extending transversely from the support plate such that the protrusions define slots 8. The slots 8, bound by adjacent protrusions, are of sufficient width to receive an electrical wire, such as a standard insulated wire for telephone connectors.
Ridges 9 are located on top surface 5 of support plate 2. Ridges 9 run in a transverse direction across the support plate between outer edges 6 and partially around protrusions 7 such that grooves 20 are bound between adjacent ridges. Ridges 9 can be a single height or multiple heights, in order to conform to the inside surface of cover plate 3. Figs. 1 and 3 demonstrate ridge 9 as including a 'standing rib 10 that extends the height of lower ridge 70. Lower ridge 70 extends to partially surround the protrusion of the universal connector. The height of standing rib 10 is such that cover plate 3, when assembled, rests on the standing ribs 10. In a preferred embodiment, the inside surface (not shown) of cover plate 3 includes indentations generally corresponding to the shape of the standing ribs 10, thus increasing the contact area between the standing ribs 10 and the cover 3.
Another embodiment, particularly useful when the ridge 9 is of uniform height, includes a flat inside . HE0077 surface of the cover plate 3 that contacts the support plate 2. Yet another alternate includes other configurations for mating with the standing rib 10 or ridge 9.
The connector 1, without sealant, is secured in any way traditional in the art, the preferred method including sonic welding. Sonic welding allows the polycarbonate base material of the support plate 2 to link to the cover plate 3 with the contacts 4 in place.
Sonic welding is used to attach the cover plate 3 to the support plate 2 prior to the introduction of the universal sealant. As the polycarbonate material of the cover plate 3 and the material of the standing ribs 10 integrally bond into a seamless material with sonic welding, close contact and increased contact area ensure a strong bond.
The support plate and cover plate of a preferred embodiment also include gates 60 and 63, respectively, at each end. Cover plate gate 63 includes female connector 62 while support plate gate 60 includes corresponding male connector 61. Prior to sonic welding, the cover plate 3 and support plate,2 are held together by connecting the female connector 62 to the corresponding male connector 61.
A short rib 11 extends partially through the groove 20 (Fig. 1 and 3), the short rib 11 being of a height less than standing rib 10. Thus, each groove 20 is bordered by two adjacent ridges 9 with the short rib 11 protruding partially through groove 20. When the universal connector is assembled, contacts 4 generally align within grooves 20. Each contact 4 is preferably a relatively thin, flexible, conductive metal substantially similar.in shape to the' groove 20, preferably with indentions 40 generally corresponding to short rib 11 such that motion in the direction of the length of the support plate 2 is constrained by the short rib 11 and the standing rib 10.
While indention 40 generally corresponds to the shape of .short rib 11, indention 40 is of such a depth that the contact 4 is suspended in groove 20 as opposed to resting at the bottom of the groove. As short ribs 11 do not extend to the same height as standing ribs .10, the short ribs 11 and at least a substantial portion of the contact 4 do not touch the cover plate 3. Thus, the contact 4 suspended from the short rib 11 in the groove 20 acts to divide the groove 20 generally into upper space 21 and lower space 22. In surrounding the contact 4, the universal sealant substantially fills the upper and lower spaces.
Contacts 4 have first end 41 and second end 42. Each end is pronged such that the first end 41 has a first prong 45 and a second prong 46. Likewise, second end 42 has a first prong 45 and a second prong 46. The contact 4 readily permits connection or disconnection of a first insulated conductor to a second insulated conductor, such as in a conventional telephone circuit wire connector. The prongs 45, 46, being of a flexible material, can be pushed apart in the longitudinal direction of the support plate. -During installation, the installer inserts a wire into a desired slot 8 in the assembled connector 1 in a direction perpendicular to the longitudinal axis of the support plate 2. The wire pushes through any sealant that is present until reaching the contact 4. As the wire is forced into the base of the slot 8, the wire presses against the contact 4 forcing the prongs 45,46 of the contact 4 to flex providing necessary space for the wire. The prongs 45,46 also act as a blade by cutting through any coating on the wire such that the contact 4 securely touches the wire.
Excess wire extending beyond the universal connector can be trimmed away. Another wire is inserted in the opposite slot 8 placing contact 4 in communication with this second wire. The circuit between the two wires in then complete.
To efficiently increase the number of contacts 4 available on the connector 1, the bottom surface of the support plate 2 also has grooves 20 for receiving contacts 4.
As best seen in Fig. 3, the standing ribs 11 on the bottom surface are staggered relative to the standing ribs 11 on the top surface such that the number of slots 8 and thus contacts possible for the given length of the support plate is virtually doubled. .
A preferred embodiment for assembling the connector includes adding the sealant 50 to distribute evenly within each groove 20. The cover plate 3 of the preferred embodiment has holes 33, with at least one hole allowing access to each groove 20. During assembly, the contacts 4 are placed into their respective grooves 20 and the cover plate 3 is attached to the support plate 2. The sealant 50, in a pre-measured quantity, is then injected through holes 33 in the cover plate 3 to fill . HE0077 the grooves 20 and surround the contacts 4. Small quantities of the sealant are used, with 0.06 grams being prefenred.
The universal sealant material of the current invention exhibits multiple desirable characteristics. This material is environmentally stable in both indoor and outdoor applications, thus avoiding the common difficulty of requiring different sealants for indoor and outdoor usage. The material allows for rehealability so that reworking is possible. The material is also inert to silicon and polycarbonate. The gel is hydrophobic or moisture insensitive.
It can be seen that proper encapsulation of the contacts 4 and/or connectors 1 requires penetration of the insulating material into the highly intricate grooves and spaces in order to fully protect the contacts and connector. The sealant 50 of the current invention exhibits low viscosity suitable for conforming to such intricate spaces while curing to a stable compound that remains in place. In a termination block where multiple wires are connecting to respective contacts, the close proximity of the wires can create electronic noise or produce an electrical short circuit within the termination block. The universal sealant of the invention is also electrically insulating such that interference is minimized or eliminated.
The sealant of the invention is a two-part mixture of isocyanate with polybutadiene rubber, such as 4441 Gella Reenterable Encapsulating Compound distributed by 3M. This composition has been used in the prior art for encapsulating printed circuit board. Applicant has discovered that this sealant has a unique combination of properties useful in particular with electrical connectors. The composition is heat stable and can be used for sealing in locations subject to elevated temperatures for extended periods. Not only does the material show low water permeability, thus reducing the possibility of corrosion, but it also shows low oil permeability, waking it useful in applications where contact with oil is possible. The universal sealant is also an effective shock absorbing and insulating material.
The preferred composition is distributed as a two-part mixture, Part A and Part B, that are non-reactive until combined. Part A contains an isocyanate, preferably aliphatic diisocyanate. Part B is a polybutadiene resin. Part A and Part B both contain a non-reactive diluent base material of heavy naphthenic distillates. Part A also can contain a quantity of hydrocinnamic acid. The two-part liquid composition is prepared by mixing the ingredients, which then slowly react together. The composition of the invention has a suitable pot life in that the mixture remains viscous for a sufl;icient amount of time to allow pouring into the connector for encapsulating the components of the connector. Off ratio blending was also tested to evaluate modulus and other characteristics of the resulting blend. Preferred embodiments include mixtures of Part A and Part B of 4441 Gella in the range from 1 A: l B to 1.75A:1 B.
To cure the sealant, the universal connector with the sealant added is baked at 65 degrees C
for ten to twenty minutes. If baking is not desired, the sealant is self curing at room temperature over a longer period of time. Higher temperatures of baking reduce the time for curing. The preferred temperature for baking is 65 degrees C as the baked universal connector with sealant can be readily handled by personnel after baking and the time required to cure is optimized.
. Positive results were obtained when testing the universal sealant with the connector for various qualities. Leakage testing included sealing the composition in the connector and curing.
The sealed connector was placed on an indicator paper in an oven at 80 degrees C to observe any leakage. No leakage was observed for the composition of the invention. Tests performed to evaluate stress included bending the component for constant stress over the entire length of the connector side to test the stress corrosion of the plastic materials with the universal sealant. After curing, the universal sealant is generally inert and chemical attack to the polycarbonate material is not expected.
For testing purposes, uncured universal sealant was used to provide an aggressive environment. No cracking was observed using the universal sealant with polycarbonate material.
A thirty day salt fog test was also successfully completed, as was a temperature-humidity cycling test.
I From the foregoing it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth, together with other advantages that are obvious and that are inherent to the apparatus and structure.
l0 It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.
Because many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.
For example, an alternate embodiment would include pre-curing the gel with the contacts in a form corresponding to the shape of tk~e connector. Likewise, extenders and plasticizers can be added to the gel. The gel can contain moisture scavengers, antioxidants, fillers, pigments, tackifier, and fungicides.
An alternate embodiment of the contacts includes a slit through the contact generally aligning with the short rib. The contact is then placed over the short rib.
This is particularly useful if the sealant is pre-cured before assembly.
The universal connector can be jacketed with an external non-conductive protective jacket when extra protection from elements, interference or shock is desirable. The universal sealant of the invention is nonreactive with silicone or greases allowing such sealants to be used in near proximity, such as in securing a jacket.
The universal sealants can also be used to environmentally protect other designs of electrical connectors or the like.
Claims (17)
1. Electrical connector for connecting telecommunication wires comprising:
a housing defining a cavity;
a plurality of insulation displacement contacts in the cavity, each contact having a first pair of blades on a first end for receiving an insulated wire between them and a second pair of blades on a second end for received another insulated wire between them, the blades cutting through insulation from the wires and establishing continuity between them;
an access hole in the housing adjacent each pair of blades for inserting of the wires; and a sealant filling the cavity to insulate the contacts and the wires, the sealant comprising an isocyanate, a polybutadiene resin, and a diluent that is inert to reaction with isocyanate and polybutadiene resin.
a housing defining a cavity;
a plurality of insulation displacement contacts in the cavity, each contact having a first pair of blades on a first end for receiving an insulated wire between them and a second pair of blades on a second end for received another insulated wire between them, the blades cutting through insulation from the wires and establishing continuity between them;
an access hole in the housing adjacent each pair of blades for inserting of the wires; and a sealant filling the cavity to insulate the contacts and the wires, the sealant comprising an isocyanate, a polybutadiene resin, and a diluent that is inert to reaction with isocyanate and polybutadiene resin.
2. The electrical connector of claim 1 wherein the isocyanate is an aliphatic diisocyanate.
3. The electrical connector of claim 2 wherein the aliphatic diisocyanate has a molecular weight greater than 500.
4. The electrical connector of claim 1 wherein the isocyanate is in an amount from 7 percent by weight to 16 percent by weight of the sealant; and the polybutadiene resin is in an amount from 25 percent by.weight to 54 percent by weight of the sealant.
5. The electrical connector of claim 1 wherein the sealant further comprises:
hydrocinnamic acid.
hydrocinnamic acid.
6. The electrical connector of claim 5 wherein the hydrocinnamic acid is in an amount from .5 percent by weight to 3 percent by weight of the sealant.
7. An environmentally sealed universal connector for electrical applications comprising:
a support plate having a top surface, a bottom surface, and outer edges, said support plate having a plurality of transverse protrusions, the protrusions defining a plurality of slots along the outer edges, the top surface including a plurality of ridges extending transversely between outer edges to partially surround protrusions such that grooves are bound between adjacent ridges;
a cover plate having outer rims, said cover plate having a plurality of transverse complementary protrusions, the protrusions defining a plurality of complementary slots along the outer rims;
a plurality of contacts generally aligning within the grooves; and a universal sealant generally filling the grooves and substantially surrounding the contacts, said universal sealant acting to connect the cover plate to the top surface of the support plate such that the slots of the support plate and the complementary slots of the cover plate are generally aligned, said universal sealant being a non-silicone sealant suitable for use indoors as well as outdoors.
a support plate having a top surface, a bottom surface, and outer edges, said support plate having a plurality of transverse protrusions, the protrusions defining a plurality of slots along the outer edges, the top surface including a plurality of ridges extending transversely between outer edges to partially surround protrusions such that grooves are bound between adjacent ridges;
a cover plate having outer rims, said cover plate having a plurality of transverse complementary protrusions, the protrusions defining a plurality of complementary slots along the outer rims;
a plurality of contacts generally aligning within the grooves; and a universal sealant generally filling the grooves and substantially surrounding the contacts, said universal sealant acting to connect the cover plate to the top surface of the support plate such that the slots of the support plate and the complementary slots of the cover plate are generally aligned, said universal sealant being a non-silicone sealant suitable for use indoors as well as outdoors.
8. The environmentally sealed universal connector or claim 7 further comprising:
a second cover plate having outer rims, said second cover plate having a plurality of transverse complementary protrusions, the protrusions defining a plurality of complementary slots along the outer rims that generally align with the slots of the support plate, said second cover being connected to the bottom surface of the support plate by the universal sealant;
wherein the bottom surface of the support plate includes a plurality of ridges extending transversely between outer edges to partially surround protrusions such that grooves are bound between adjacent ridges, the ridges on the bottom surface being longitudinally staggered relative to the ridges on the top surface.
a second cover plate having outer rims, said second cover plate having a plurality of transverse complementary protrusions, the protrusions defining a plurality of complementary slots along the outer rims that generally align with the slots of the support plate, said second cover being connected to the bottom surface of the support plate by the universal sealant;
wherein the bottom surface of the support plate includes a plurality of ridges extending transversely between outer edges to partially surround protrusions such that grooves are bound between adjacent ridges, the ridges on the bottom surface being longitudinally staggered relative to the ridges on the top surface.
9. The environmentally sealed universal connector of claim 8 further comprising:
a plurality of short ribs disposed between adjacent ridges, the short ribs extending partially through the grooves;
wherein the contacts include a longitudinal indention generally corresponding to the short rib such that motion of the contacts is partially constrained by the short ribs, the contact being suspended from the short rib in the groove such that the groove is divided into an upper and lower space.
a plurality of short ribs disposed between adjacent ridges, the short ribs extending partially through the grooves;
wherein the contacts include a longitudinal indention generally corresponding to the short rib such that motion of the contacts is partially constrained by the short ribs, the contact being suspended from the short rib in the groove such that the groove is divided into an upper and lower space.
10. The environmentally sealed universal connector of claim 7 wherein the universal sealant comprises:
an isocyanate;
a polybutadiene resin; and a diluent that is inert to reaction with isocyanate and polybutadiene resin.
an isocyanate;
a polybutadiene resin; and a diluent that is inert to reaction with isocyanate and polybutadiene resin.
11. The environmentally sealed universal connector of claim 10 wherein the universal sealant further comprises:
hydrocinnamic acid.
hydrocinnamic acid.
12. An environmentally sealed universal connector for electrical applications comprising:
a support plate having a top surface;
a cover plate that, when attached to said support plate, defines a cavity between the cover plate and support plate;
a plurality of insulation displacement contacts in the cavity, each contact having a first pair of blades on a first end for receiving an insulated wire between them and a second pair of blades on a second end for received another insulated wire between them, the blades stripping insulation from the wires and establishing continuity between them;
an access hole in the housing adjacent each pair of blades for inserting of the wires; and a sealant filling the cavity to insulate the contacts and the wires, the sealant comprising an isocyanate, a polybutadiene resin, and a diluent that is inert to reaction with isocyanate and polybutadiene resin.
a support plate having a top surface;
a cover plate that, when attached to said support plate, defines a cavity between the cover plate and support plate;
a plurality of insulation displacement contacts in the cavity, each contact having a first pair of blades on a first end for receiving an insulated wire between them and a second pair of blades on a second end for received another insulated wire between them, the blades stripping insulation from the wires and establishing continuity between them;
an access hole in the housing adjacent each pair of blades for inserting of the wires; and a sealant filling the cavity to insulate the contacts and the wires, the sealant comprising an isocyanate, a polybutadiene resin, and a diluent that is inert to reaction with isocyanate and polybutadiene resin.
13. The electrical connector of claim 12 wherein the isocyanate is an aliphatic diisocyanate.
14. The electrical connector of claim 13 wherein the aliphatic diisocyanate has a molecular weight greater than 500.
15. The electrical connector of claim 12 wherein the isocyanate is in an amount from 7 percent by weight to 16 percent by weight of the sealant; and the polybutadiene resin is in an amount from 25 percent by weight to 54 percent by weight of the sealant.
16. The electrical connector of claim 12 wherein the sealant further comprises:
hydrocinnamic acid.
hydrocinnamic acid.
17. The electrical connector of claim 16 wherein the hydrocinnamic acid is in an amount from .5 percent by weight to 3 percent by weight of the sealant.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US38210599A | 1999-08-24 | 1999-08-24 | |
| US09/382,105 | 1999-08-24 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2314812A1 true CA2314812A1 (en) | 2001-02-24 |
Family
ID=23507539
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2314812 Abandoned CA2314812A1 (en) | 1999-08-24 | 2000-08-02 | Non-silicone sealant for universal indoor-outdoor applications and insulation-displacement cross connector |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2314812A1 (en) |
-
2000
- 2000-08-02 CA CA 2314812 patent/CA2314812A1/en not_active Abandoned
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| Date | Code | Title | Description |
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