Illumination device having elongated light pipe and one or more attachment wings

An illumination device that includes an elongated light pipe and attachment wings integrally formed on the sides of the light pipe so that the illumination device can be easily, yet securely, installed within a containment channel, such as those found on the underside of a vehicle step rail. The elongated light pipe is made of an optically transmissive material, the attachment wings are made of a different resilient material, and the overall device is a single extruded component that has a co-extrusion boundary separating the two materials. The illumination device illuminates the ground, for example, when passengers are entering or exiting the vehicle.

FIELD

The present invention generally relates to an illumination device and, more particularly, to an illumination device for installation on a vehicle, such as on the underside of a vehicle step rail.

BACKGROUND

Step rails and other vehicle components are sometimes designed to provide exterior lighting for when a user is entering and/or exiting the vehicle. For example, some step rail illumination devices include a series of individual lamps (e.g., light-emitting diodes (LEDs)) that are mounted on the underside of the step rail and emit light downwards so as to provide ground illumination; these devices are referred to here as ‘multi-lamp’ devices. Typically, each lamp in a multi-lamp device is mounted in an individual socket, is connected to other lamps by way of wire harnesses, and produces a localized light pattern beneath the lamp.

Although this type of arrangement may be useful for certain applications, it may also come with certain drawbacks. For instance, multi-lamp devices can sometimes produce a non-uniform light pattern underneath the device that undesirably includes a series of bright and dark spots corresponding to the different locations of the lamps; the non-uniformity of such a pattern can become exacerbated if one or more of the lamps burns out or otherwise malfunctions. In addition, multi-lamp devices with a series of interconnected lamps and wire harnesses can be expensive and difficult to install and connect.

The illumination device described below was designed with some of the aforementioned considerations in mind.

SUMMARY

According to one embodiment, there is provided an illumination device for installation in a containment channel, comprising: an elongated light pipe made of an optically transmissive material and having a reflecting side that reflects light within the light pipe, an illuminating side that allows light to escape the light pipe, a first attachment side, and a second attachment side; a first attachment wing made of a resilient material and having a first bridge portion that connects the first attachment wing to the first attachment side of the elongated light pipe, a first arm portion that extends away from the first bridge portion, and a first leg portion that extends away from the first bridge portion; and a second attachment wing made of a resilient material and having a second bridge portion that connects the second attachment wing to the second attachment side of the elongated light pipe, a second arm portion that extends away from the second bridge portion, and a second leg portion that extends away from the second bridge portion. The illumination device is configured so that, during installation of the illumination device in the containment channel, the first and second attachment wings resiliently snap into the containment channel and securely maintain the illumination device in place.

According to another embodiment, there is provided an illumination device for installation in a containment channel, comprising: an elongated light pipe made of an optically transmissive material and having a reflecting side that reflects light within the light pipe, an illuminating side that allows light to escape the light pipe, and at least one attachment side; and at least one attachment wing made of a resilient material and having a bridge portion that integrally joins the attachment wing to the attachment side of the elongated light pipe, the attachment wing is configured to help secure the illumination device in the containment channel. The illumination device is a single extruded component that has a co-extrusion boundary separating the optically transmissive material of the elongated light pipe from the resilient material of the attachment wing.

According to yet another embodiment, there is provided a method of manufacturing an illumination device, comprising the steps of: providing an optically transmissive material to an extruding machine; providing a resilient material to the extruding machine; co-extruding the optically transmissive material and the resilient material to form a single extruded component that includes an elongated light pipe, at least one attachment wing, and a co-extrusion boundary separating the optically transmissive material from the resilient material; and severing the co-extruded material at an axial end. The elongated light pipe is formed from the optically transmissive material and has a reflecting side that reflects light within the light pipe, an illuminating side that allows light to escape the light pipe, and at least one attachment side. The attachment wing is formed from the resilient material and has a bridge portion that integrally joins the attachment wing to the attachment side of the elongated light pipe, the attachment wing is configured to help secure the illumination device in a containment channel. The co-extrusion boundary is located in the bridge portion of the attachment wing.

DESCRIPTION

An illumination device is described herein that includes an elongated light pipe and one or more attachment wing(s) integrally formed on the sides of the light pipe so that the illumination device can be easily, yet securely, installed within a containment channel, such as the type found on the underside of a vehicle step rail. The elongated light pipe is made of an optically transmissive material, the attachment wing(s) are made of a different resilient material, and the overall device is a single extruded component that has a co-extrusion boundary separating the two materials. The illumination device may be used in vehicle and/or non-vehicle applications, in vehicle interior and/or exterior applications, as well as in a number of different vehicle applications, to cite a few possibilities. The vehicle step rail embodiment described below is merely one possibility, as other applications may include other vehicle exterior lighting applications (e.g., those in bumpers, truck beds, body panels, etc.), vehicle interior lighting applications (e.g., those in interior trim, door and roof panels, instrument panels, etc.), as well as lighting applications for buildings (e.g., down or track lighting, accent lighting, etc.). Further, vehicle implementations are not limited to pickup trucks (as shown inFIG. 1), as the illumination device may be used on any sports utility vehicle (SUV), cross-over vehicle, passenger vehicle, motorcycle, marine vehicle, aircraft, all-terrain vehicle, etc.

The exemplary step rail assembly10shown inFIGS. 1-3is mounted on a vehicle12and includes a step rail14, a containment channel16, and an illumination system18. The step rail14, also referred to as a ‘running board’, is an elongated component that typically extends along a length of the vehicle12(e.g., under front and/or rear passenger doors) and includes an upper surface30for passengers to step on as they enter or exit the vehicle, as well as a lower surface32, side surfaces34,36, and an interior space38. In this particular embodiment, the step rail14has a rectangular cross-sectional shape and the lower surface32includes an opening or slot40that extends along a length of the step rail and is designed to accommodate the containment channel16so that the illumination system18can emit light downwards towards the ground, as illustrated inFIGS. 1 and 3.

Containment channel16is also an elongated component that extends for a length of the step rail14and similarly includes an upper surface50, a lower surface52, side surfaces54,56, and an interior space58. Like the larger step rail14, the containment channel16may also have a generally rectangular cross-sectional shape where the lower surface52includes an opening or slot60that extends along a length of the containment channel and is designed to accommodate the illumination system18. As best illustrated inFIG. 3, the lower surface52of the containment channel16includes a pair of flanges62,64that are parallel to and are separated from one another across the width of the opening60.

In one embodiment, the step rail14is manufactured separate from the containment channel16so that the two components can later by welded, bolted or otherwise secured to one another. The step rail14and/or the containment channel16may be made from aluminum, an aluminum-based alloy, or some other suitable material. The cross-sectional shape of the step rail14and/or the containment channel16may be rectangular, as shown and described, but this is not required. Because step rails and their installation on vehicles are generally known in the art, they will not be described further here. It should be appreciated that terms of relative direction and position, such as “upper,” “lower,” “front,” “rear,” “above,” “below,” and the like are generally used in the context of the longitudinal axis A of the vehicle and are not intended to be limiting.

Turning now toFIG. 2, there is shown an exploded schematic view of an upside down step rail14and the illumination system18, where the illumination system includes a wiring harness70, light engines72, an illumination device74, and end caps76. The wiring harness70is routed and secured within the containment channel16located on the underside of the step rail14. The wiring harness70is designed to connect the illumination system18with the vehicle electrical system and includes one or more sealed connectors80for providing power and/or control signals to the light engines72. The light engines72are electrically connected to the wiring harness70by way of the sealed connectors80and are arranged to shine light into axial ends of the illumination device74so that the light can be transmitted within the illumination device according to principals of total internal reflection (TIR). According to one embodiment, each of the light engines70is maintained within a sealed housing and includes light emitting diodes (LEDs) or other suitable light sources that can generate enough light to be uniformly distributed along the length of the illumination device74. The illumination device74includes an elongated light pipe90, first and second attachment wings92,94, and first and second axial ends100,102, as will be described in greater detail. Each axial end100,102is preferably laser cut to include snaps or tabs104that facilitate connection with a corresponding light engine housing. The end caps76are designed to slide into axial ends of the step rail14so that the interior space38inside of the step rail is generally sealed off at the ends. It should be appreciated that the aforementioned description of illumination system18is non-limiting and is simply provided as an example of how such a system could be structured. Other illumination systems, including those with different combinations of components, may be used with the illumination device described and claimed herein.

With reference toFIGS. 4 and 5, there is shown an embodiment of the illumination device74that is designed to resiliently fit within a channel, such as containment channel16located on the underside of the step rail14, and includes an elongated light pipe90and first and second attachment wings92,94. One potential advantage of the present design is that the overall illumination device74is preferably made as a single extruded component having a co-extrusion boundary located between the different materials of the elongated light pipe90and each of the attachment wings92,94. By extruding or otherwise manufacturing the device as a unitary component, the present design is able to reduce the number of parts involved, minimize the complexity of the assembly process, and improve the overall durability or robustness of the device, to cite several possibilities. Since the first and second attachment wings92,94are generally the same, except for being connected on opposing sides of the light pipe90, only one of the wings is described below with the understanding that the description applies to both.

Elongated light pipe90is designed to receive light from a light engine72at an axial end100,102and to transmit and distribute the light along its axial length so that it can illuminate the ground below. Because the light pipe90needs to transmit or convey light along at least a part of its axial length according to principals of total internal reflection (TIR), the light pipe is preferably made of an optically transmissive material, such as poly(methyl methacrylate) (PMMA). Of course, light pipe90is not limited to PMMA, as other transparent materials, including various types of thermoplastics, acrylics and/or glass compounds could be used instead. According to the non-limiting example shown inFIG. 4, the elongated light pipe90is an extruded optical core that generally has a circular cross-sectional shape and includes a reflecting side110, an illuminating side112, and first and second attachment sides114,116.

Reflecting side110is located towards the upper portion of the light pipe90and is designed to reflect or otherwise guide light back into the body of the light pipe. With reference toFIG. 4, the reflecting side110may include an outer surface of the upper half of the light pipe90anywhere between the first and second attachment sides114,116, as indicated by the curved bracket associated with reference numeral110. In some instances, the reflecting side110may be coated along a portion of its axial length with a metallic or other reflective coating designed to promote internal reflection of the light. In other instances, the reflecting side110may be manufactured with various optics, such as laser or machine etched grooves or channels, configured to reflect light towards the illuminating side112so that it exits the light pipe. The exact positioning and arrangement of such optics may depend on a number of factors, including the relative axial distance from the light engine72. Any suitable reflecting side feature may be employed to achieve the desired light distribution pattern.

Illuminating side112is located towards the lower portion of the light pipe90, opposite the reflecting side112, and is designed to allow light to escape the light pipe in order to illuminate the area below. The illuminating side112may include an outer surface of the lower half of the light pipe90anywhere between the first and second attachment sides114,116, as indicated by the curved bracket associated with reference numeral112. The illuminating side is shown in the drawings as having a semi-circular shape, however, this is not mandatory. It is possible, for example, for the illuminating side to have a flat or other contoured shape; an example of which is shown in dashed lines and is identified as112′. It is also possible for the illuminating side112to be coated with a suitable coating to promote refraction out of the light pipe or to be equipped with optics, like those on the opposing reflecting side110, to control or influence the illumination pattern or distribution.

First and second attachment sides114,116are located on the lateral portions of the light pipe90and are designed to connect with attachment wings92,94, respectively. Because the first and second attachment sides114,116of this embodiment are of the same design, only side114is described below. It should be understood, however, that the following description applies to side116as well. The first attachment side114is integrally formed with the first attachment wing92and it can extend the entire axial length of the light pipe90; the enlarged perspective view towards the bottom ofFIG. 2illustrates this lateral connection along the length of the light pipe. In addition to serving as a structural connection with the first attachment wing92, the first attachment side114is proximate a transition region that includes a co-extrusion boundary132separating the different materials of the elongated light pipe90and the attachment wing92. First attachment side114is illustrated inFIGS. 4 and 5with a solid line that generally denotes a boundary or beginning of the transition region; however, it should be appreciated this line is for purposes of illustration, as actual manufactured parts may not contain such a definitive boundary or line at114. The exact positioning of the co-extrusion boundary132can impact the optical performance of the light pipe, as well as the resiliency of the connection between components90and92, as explained below in more detail.

First and second attachment wings92,94are designed to resiliently snap into the containment channel16so that the illumination device74can be easily and securely installed on the underside of the step rail14. Because the attachment wings92,94need to flex slightly when they are snapped into the containment channel16, but also need to be strong enough to firmly maintain the illumination device74in place, the attachment wings are preferably made of a strong resilient material, such as acrylonitrile butadiene styrene (ABS). Furthermore, it is desirable to prevent light within the elongated light pipe90from leaking into the attachment wings92,94, thus, instead of being made of optically transmissive material, the attachment wings are preferably made of a reflective and/or opaque material, such as a extruded-in-white ABS. Of course, the attachment wings are not limited to white ABS, as other types of strong, tough, resilient and/or opaque plastic materials could be used instead. According to the non-limiting example shown inFIG. 4, the first attachment wing92is a wing-like component that includes a bridge portion120, an arm portion122, and a leg portion124. Since the first and second attachment wings92,94of this embodiment are of the same design, only wing92is described below. It should be understood, however, that the following description applies to wing94as well.

Bridge portion120connects the first attachment wing92to the first attachment side114of the light pipe90and is also part of a transition region that includes a co-extrusion boundary between the materials of components90and92. The bridge portion120may be located towards the middle of the first attachment wing92and is preferably thick enough to create a strong and resilient connection with the first attachment side114of the light pipe. For example, a light pipe90with a diameter of about 10 mm should have a bridge portion120with a thickness of about 2 mm. According to the illustrated embodiment, the bridge portion120laterally or outwardly extends from the first attachment side114of the light pipe to an outer end130and includes a co-extrusion boundary132located therebetween. The co-extrusion boundary separates the optically transmissive material of the light pipe90with the resilient material of the attachment wing92and may be a definitive boundary or interface or it may be a transitional region where one material fades into the other. By locating the co-extrusion boundary132in the transition region, the boundary or material interface is close enough to the light pipe so that the overwhelming majority of light in the light pipe is prevented from leaking out through the bridge portion. Depending on the materials and applications involved, the co-extrusion boundary132can be adjusted to optimize device performance. An example of this optimization is illustrated by boundary132which is located a position that is closer to the attachment side114of the light pipe90(distance D1) than it is to the outer end130of the attachment wing92(distance D2) so that the majority of light incident on side114is reflected back into the light pipe and does not leak out through the bridge portion120. Co-extrusion boundary132′, on the other hand, is located about halfway between side114and end130and is spaced from the light pipe by a distance D3which may allow somewhat more light leakage, but can potentially provide more resiliency to the bridge portion.

Arm portion122extends upwards and away from the bridge portion120and, during installation within containment channel16, is designed to resiliently flex within the channel. The exact configuration of the arm portion122can vary from the exemplary embodiment shown in the drawings, but according to that design, the arm portion122includes a series of bends or transitions140,142,144that culminate in a downwardly turned flange146.

Leg portion124is the converse of arm portion122and extends downwards and away from the bridge portion120and is also designed to resiliently flex somewhat during installation of the illumination device74in the containment channel16. The leg portion124preferably includes a stepped flange150that is sized and shaped to interact with the flange62of the containment channel16. This interaction is described in the following paragraph in conjunction withFIGS. 6-9.

During manufacturing, the illumination device may be formed using one of a number of different co-extrusion process. For example, a method may include the following steps: providing an optically transmissive material to an extruding machine; providing a resilient material to the extruding machine; co-extruding the optically transmissive material and the resilient material to form a single extruded component that includes an elongated light pipe, at least one attachment wing, and a co-extrusion boundary separating the optically transmissive material from the resilient material (a non-limiting example of such a component is described above); and severing the co-extruded material at an axial end.

During installation, the illumination device74is first partially inserted into an axial end of the containment channel16and is then slid into place. This stage corresponds toFIG. 6, where it is seen that the arm portions122of the first and second attachment wings92,94are fully inserted within the interior space58of the containment channel16, whereas the leg portions124of the same attachment wings are not. Next, an upward force F is applied to the illumination device74so that the leg portions124of the first and second attachment wings92,94are resiliently urged or squeezed together so that they fit through the elongated opening60in the containment channel16. This stage is illustrated inFIG. 7. Continued upward force F causes the arm portions122of the first and second attachment wings92,94to contact an interior surface of the containment channel surface50and deflect slightly downwards, towards leg portions124; this downward deflection or urging may also result in the flanges146of wings92,94spreading out from one another. At the same time, the leg portions124have been pushed far enough up into the interior space58of the containment channel16so that stepped flanges150clear the elongated opening60and nest with the pair of flanges or edges62,64in the channel. This stage is reflected inFIG. 8. At this stage, the upward force F that is used to install the illumination device74into the containment channel16can be removed and the illumination device will remain aligned and firmly secured within the channel, as shown inFIG. 9.

It should be appreciated that the aforementioned installation process can be carried out without the need for additional mounting hardware, sealant or adhesives to attach the illumination device74and/or illumination system18to the underside of the step rail14. Thereby reducing complexity for both assembly and installation.

It is to be understood that the foregoing is a description of one or more preferred exemplary embodiments of the invention. The invention is not limited to the particular embodiment(s) disclosed herein, but rather is defined solely by the claims below. For example, even though all of the illustrated embodiments show two attachment wings that are mirror images of one another, it is possible for the illumination device to include more or less than two attachment wings and/or to include attachment wings that are not mirror images and are, thus, different from one another. As another example, one or more of the different components of the illumination device, such as the elongated light pipe, may have a non-uniform cross-sectional shape and/or size along its length. It is also possible for various types of known optics or other light reflecting and/or refracting features to be applied to the illumination device described herein, as well as elongated and transparent covers or lens to enclose openings40and/or60. The statements contained in the foregoing description relate to particular embodiments and are not to be construed as limitations on the scope of the invention or on the definition of terms used in the claims, except where a term or phrase is expressly defined above. Various other embodiments and various changes and modifications to the disclosed embodiment(s) will become apparent to those skilled in the art. All such other embodiments, changes, and modifications are intended to come within the scope of the appended claims.