Vented wireway grommet

Abstract

: The invention relates to a device and method for providing a vent tube in combination with a wire assembly in a luminaire grommet. In particular, the invention provides a wireway grommet design which enables access of both a vent tube and wire connections through a single access hole in the luminaire's housing.

Description

[0001] VENTED WIREWAY GROMMET

[0002] FIELD OF THE INVENTION

[0003] The invention relates to a device and method for providing a vent tube in combination with a wire assembly in a luminaire grommet. In particular, the invention provides a wireway grommet design which enables access of both a vent tube and wire connections through a single access hole in the luminaire’s housing. The tubular ventilation device of the present invention can be placed in the same area as the field supply wires and provide a method to release internal negative pressures without the intrusion of water or other contaminates.

[0004] BACKGROUND

[0005] Outdoor mounted electrical devices such as outdoor luminaires, need to be electrically connected in a manner that restricts water from entering the luminaire’s housing. Moreover, international standards EN 60529 (e.g., IP66 as per ANSI C136.25) define specifications on outdoor lighting that require highly demanding Water Ingress Protection. These specifications address the potential problem of water being sucked into a luminaire’s housing with large temperature swings during lab testing and field issues.

[0006] One way to overcome this problem is to vent the air pressure differential by using a hydrophobic vent pad, or vent assembly in the luminaire housing. In the prior art, these vents require a secondary through hole or machine threaded hole to match the vent’s interface. Similar holes in the housing are used for supply wire grommets, bushings or wire glands. The requirement of additional holes requires additional expense in manufacturing as well introduces further potential water access points due to improper alignment issues and / or deterioration of the connections.

[0007] This document describes systems and methods that are intended to address at least some issues discussed above and / or other issues as discussed below.

[0008] SUMMARY OF THE INVENTION

[0009] This invention is a design for consolidating the luminaire wire assembly and vent assembly functions into a single component that requires only one hole for installation. The design is providing a molded wireway grommet (i.e. bushings or wire glands) with a venting tube which stabilizes the light fixture internal pressure and the external atmospheric pressure. The single grommet combines the supply wires (or cable) and a tube. This tube can have various degrees of the water vapor protection. This tubular ventilation device can be situated alongside the field supply wires and functions as a reliable mechanism for releasing internal negative pressures, while preventing unwanted water or other impurities from infiltrating the system through a polytetrafluoroethylene (PTFE) membrane.

[0010] It should be appreciated that all combinations of the foregoing concepts and additional concepts discussed in greater detail below (provided such concepts are not mutually inconsistent) are contemplated as being part of the inventive subject matter disclosed herein. In particular, all combinations of claimed subject matter appearing at the end of this disclosure are contemplated as being part of the inventive subject matter disclosed herein. It should also be appreciated that terminology explicitly employed herein that also may appear in any disclosure incorporated by reference should be accorded a meaning most consistent with the particular concepts disclosed herein.

[0011] BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Further details, aspects, and embodiments of the invention will be described, by way of example only, with reference to the drawings. Elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. In the figures, elements which correspond to elements already described may have the same reference numerals. In the drawings,

[0013] Fig. 1 illustrates a cross sectional view of the invention attached to a luminaire opening;

[0014] Figs. 2a-2c illustrate various embodiments of the distal end of the vent tube exterior to the luminaire’s interior; and,

[0015] Figs. 3a and 3b illustrate an embodiment of the invention in which an adhesive-backed, disc-shaped membrane assembly is employed in combination with the vent tube.

[0016] DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0017] While this invention is susceptible of embodiment in many different forms, there are shown in the drawings and will herein be described in detail one or more specific embodiments, with the understanding that the present disclosure is to be considered as exemplary of the principles of the invention and not intended to limit the invention to the specific embodiments shown and described. In particular, the following discussion relates primarily to a molded grommet comprising input electrical wires and a vent tube for use in the installation of an outdoor luminaire. The invention is not so limited as other embodiments are contemplated by the invention.

[0018] In the following, for the sake of understanding, elements of embodiments are described in operation. However, it will be apparent that the respective elements are arranged to perform the functions being described as performed by them.

[0019] Further, the invention is not limited to the embodiments, and the invention lies in each and every novel feature or combination of features described herein or recited in mutually different dependent claims.

[0020] Fig. 1 shows a molded grommet 100 in accordance with one embodiment of the present invention, attached to an access hole in the housing of a luminaire. The grommet 100 in use, is used to make electrical connections to a luminaire. To that end, the grommet comprises electrical wires 110 used to make electrical connections between a power source (not shown) and the interior of the luminaire 120. The grommet further comprises an over molded resin 160 encapsulating the wires 110 and vent tube or vent tube assembly 130 which provides an air passage way to vent the interior of the luminaire. In the embodiment illustrated in Fig. 1, the end of the vent tube, exterior to the luminaire, comprises a hydrophobic breather 140, thereby preventing water from entering the luminaire via the vent tube 130. In the embodiment of the invention depicted in Fig. 1, the hydrophobic breather 140 is secured in place with an adhesive shrink tube 315. The As discussed below, other terminations of the vent tube are contemplated by the invention.

[0021] The molded grommet 100 can be circular and include a snap-in portion 101, and a back-stop portion 102. The snap-in portion 101, for example, has a predetermined diameter and the back-stop portion 102 has a larger diameter. When properly inserted in the access hole, the grommet 100 in combination with the edges of the luminaire access hole 50 creates a sealed enclosure wall 150 with the interior of the luminaire. In particular, the snap- in portion 101 is pushed or inserted into the luminaire access hole 50 and the back portion 102, 103 both stop the molded grommet 100 from completely entering through the access hole and creates the seal with the access hole 50 and the enclosure wall 150 of the luminaire.

[0022] Figs. 2a-2c illustrate various embodiments of the distal end of the vent tube, that is, the end exterior to the luminaire’s interior. In Fig. 2a, the vent tube 130 terminates at its distal end 200 in a simple cut — there is no additional component added to the distal end 200. This embodiment would be employed in situations where the tube is venting directly into a waterproof space, such as the luminaire’s supply junction box to which the luminaire is mounted.

[0023] In Fig. 2b, tube 130 is constructed to form a cavity which filters out water vapor. Such a cavity terminates in a polytetrafluoroethylene (PTFE) filter 210 or, which can be made from a sealed decal 300 comprising a PTFE layer (as illustrated in Fig. 3a and discussed below). The hydrophobic breather 140 is secured in place with an adhesive shrink tube 315.

[0024] In additional embodiments, the distal end of tube 130 is constructed to include one or more features to hold a hydrophobic breather component 220 onto the tube end. Fig. 2c illustrates one such embodiment in which a pressed fit is employed.

[0025] Further embodiments are depicted in Figs. 3a and 3b in which an adhesive backed, disc-shaped membrane assembly is employed. Such PTFE porous products are manufactured by NITTO DENKO under the product name “TEMISH” and by W. L. Gore & Associates under the product name “Gore-Tex.” As illustrated in Fig. 3a, the product comprises a layer of Silicone adhesive with polyester film substrate 320 which encircles the bottom layer of a PTFE porous membrane 330. A Polyester net 340 is also shown.

[0026] Fig. 3b illustrates how the disc-shaped membrane assembly is employed to cover the distal end 200 of the vent tube In particular, the PTFE porous membrane layer 330 is positioned to cover all or part of the opening of the vent tube at its distal end 200. The discshaped membrane is then bent and crimped so that the adhesive layer bonds to the vent tube 130 and to itself, thereby making a secure air-tight connection but for air passing through the membrane 330.

[0027] The above discussion referenced a “molded grommet” throughout. In a preferred embodiment of the invention, the construction of the grommet occurs by an “overmolding process.” Such a process is well-known. Overmolds are usually made of thermoplastics like PVC and TPE that bond to the wire jacket, thus forming a watertight seal. Because overmolds are produced from custom tooling that resembles injection and compression molded members, sealing surfaces such as lips or ribs can be molded in to the overmold. In the current invention, the vent tube, in addition to the electrical wires, are positioned and sealed in the overmolding process.

[0028] The foregoing detailed description has set forth a few of the many forms that the invention can take. The above examples are merely illustrative of several possible embodiments of various aspects of the present invention, wherein equivalent alterations and / or modifications will occur to others skilled in the art upon reading and understanding of the present invention and the annexed drawings. In particular, regard to the various functions performed by the above described components (devices, systems, and the like), the terms (including a reference to a "means") used to describe such components are intended to correspond, unless otherwise indicated to any component, such as hardware or combinations thereof, which performs the specified function of the described component (i.e., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the illustrated implementations of the disclosure.

[0029] Although a particular feature of the present invention may have been illustrated and / or described with respect to only one of several implementations, such feature may be combined with one or more other features of the other implementations as may be desired and advantageous for any given or particular application. Furthermore, references to singular components or items are intended, unless otherwise specified, to encompass two or more such components or items.

[0030] As used herein in the specification and in the claims, “or” should be understood to have the same meaning as “and / or” as defined above. For example, when separating items in a list, “or” or “and / or” shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as “only one of’ or “exactly one of,” or, when used in the claims, “consisting of,” will refer to the inclusion of exactly one element of a number or list of elements. In general, the term “or” as used herein shall only be interpreted as indicating exclusive alternatives (i.e. “one or the other but not both”) when preceded by terms of exclusivity, such as “either,” “one of,” “only one of,” or “exactly one of.” “Consisting essentially of,” when used in the claims, shall have its ordinary meaning as used in the field of patent law.

[0031] As used herein in the specification and in the claims, the phrase “at least one,” in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase “at least one” refers, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, “at least one of A and B” (or, equivalently, “at least one of A or B,” or, equivalently “at least one of A and / or B”) can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc.

[0032] It should also be understood that, unless clearly indicated to the contrary, in any methods claimed herein that include more than one step or act, the order of the steps or acts of the method is not necessarily limited to the order in which the steps or acts of the method are recited.

Claims

CLAIMS:

1. A molded grommet to be used in wire connections to an electrical device, the electrical device comprising a housing having an access hole allowing wire passage, the molded grommet comprising: a snap-in portion, and a back-stop portion, wires for providing an electrical connection to an external source; and, a vent tube; wherein the vent tube has a proximate end located inside of the housing and a distal end located outside the housing; wherein the molded grommet creates a substantially waterproof connection with each of the wires and with the vent tube using a molded resin that individually encapsulates the wires and vent tube; and wherein the snap-in portion of molded grommet is pushed / inserted into the access hole thereby creating a substantially waterproof connection with the housing and the back-stop portion of the molded grommet.

2. A molded grommet according to claim 1 wherein the device is a luminaire.

3. A molded grommet according to claim 2 wherein: the luminaire is mounted to a supply junction box having a substantially water-proof interior; and, the distal end terminates in the interior of the supply junction box.

4. A molded grommet according to claim 2 wherein the vent tube is constructed to include a cavity having a filter which filters out water vapor.

5. A molded grommet according to claim 4 wherein the filter comprises a sealed chamber of polytetrafluoroethylene (PTFE).

6. A molded grommet according to claim 5 wherein the distal end of the tube comprises a PTFE porous membrane layer.

7. A molded grommet according to claim 6 wherein the PTFE porous membrane layer is a component of a filter assembly, which filter assembly comprising a polyester net layer and an adhesive layer.

8. A molded grommet according to claim 7 wherein the filter assembly is a discshaped filter assembly and wherein the filter assembly is attached to the distal end of the tube by employing the adhesive layer.

9. A molded grommet according to claim 6 wherein the distal end of the vent tube comprises a shrink tube which secures the PTFE porous membrane layer in place.

10. A molded grommet according to claim 1 wherein the grommet is constructed by an overmolding process.

11. A molded grommet according to claim 1 wherein the grommet is constructed using a rubber over-mold plastic injection process.

Images