Light emitting diode (LED) based street light and other lighting applications

An LED lamp module for use with a threaded electrical socket connector is provided, which includes an LED light engine with a first electrical connector, a second electrical connector having a first end electrically engagable with the first electrical connector and a second end having a threaded outer surface compatible with a threaded electrical socket connector. The LED lamp module further comprises a sleeve surrounding the first electrical connector and the first end such that the sleeve allows for relative rotation between the first electrical connector and the first end in a loosened state, and restricts relative rotation between the first electrical connector and the first end in a tightened state. A method for installing a retrofit LED lamp module in a housing which physically restricts full rotation of an LED light engine is also provided. The method includes connecting a first electrical connector to a second electrical connector, wherein the first electrical connector is attached to an LED light engine, and wherein the second electrical connector further comprises a first end electrically engagable with the first electrical connector, and a second end having a threaded outer surface compatible with a threaded electrical socket connector. The method further comprises tightening this connection via a sleeve surrounding the first electrical connector and the first end such that the sleeve allows for relative rotation between the first electrical connector and the first end in a loosened state, and restricts relative rotation between the first electrical connector and the first end in a tightened state.

FIELD OF THE INVENTION

The present invention relates to the design and the installation of retrofit Light Emitting Diode (LED) modules to replace existing light sources including street lights, parking lot lights, and various other lighting applications. More particularly, the present invention relates to a method for installing a retrofit LED lamp module in a housing which physically restricts full rotation of an LED light engine.

BACKGROUND OF THE INVENTION

Light Emitting Diodes (LEDs) have been used in many applications to replace conventional incandescent lamps, fluorescent lamps, neon tube and fiber optics light sources in order to reduce costs and to increase reliability. Due to the fact that LEDs consume less electrical energy than most conventional light sources, while exhibiting much longer lifetime, many designs could be made for various applications, such as traffic signal lights, channel letters, conventional illuminated commercial signs, street name signs, and street lights.

In the case of street lights, parking lot lights and area illumination lights, most existing products utilize HID lamps as their respective light source. Cobrahead luminaires and shoebox luminaires are two frequently used outdoor luminaires for such applications. A cross section schematic drawing of a conventional cobrahead luminaire is provided inFIG. 1a. As illustrated, such a cobrahead luminaire comprises a lamp100, a lens110, incoming AC lines120, a cobra housing130, a reflector140, and a lamp socket150. InFIG. 1b, a cross section schematic drawing of a conventional shoebox luminaire is also provided. As illustrated, such a shoebox luminaire comprises a lamp200, a lens210, incoming AC lines220, a shoebox housing230, a reflector240, and a lamp socket250.

Major disadvantages of using these lamps, however, are 1) they need to be replaced often due to the shorter lifespan of the lamp; 2) part of the light from the HID lamp is wasted because it is aimed in directions not useful to the original lighting purpose; 3) some of them contain hazardous material; and 4) they exhibit a non-favorable spectrum at night. It is therefore desirable to replace existing HID lamps with long-lasting LED products.

Current LED retrofitting mechanisms are also limited. For example, current retrofitting methods require LED light engines to be screwed onto their respective housings. However, physical constraints of the housing sometimes do not allow for LED light engines to fully rotate. It is therefore desirable to also develop a retrofitting method wherein the LED light engine does not need to be fully rotated.

SUMMARY OF THE INVENTION

The present invention solves the aforementioned problems by providing an LED lamp module that does not require the LED light engine to attach to a housing via full rotation.

The LED lamp module of the present invention is for use with a threaded electrical socket connector and includes an LED light engine with a first electrical connector and having a plurality of LEDs mounted to a printed circuit board, a second electrical connector having a first end electrically engagable with the first electrical connector and a second end having a threaded outer surface compatible with a threaded electrical socket connector. The LED lamp module further comprises a sleeve surrounding the first electrical connector and the first end such that the sleeve allows for relative rotation between the first electrical connector and the first end in a loosened state, and restricts relative rotation between the first electrical connector and the first end in a tightened state.

Another aspect of the present invention is a method for installing a retrofit LED lamp module in a housing which physically restricts full rotation of an LED light engine. This method includes connecting a first electrical connector to a second electrical connector, wherein the first electrical connector is attached to the LED light engine, and wherein the second electrical connector further comprises a first end electrically engagable with the first electrical connector, and a second end having a threaded outer surface compatible with a threaded electrical socket connector. This method further comprises tightening this connection via a sleeve surrounding the first electrical connector and the first end such that the sleeve allows for relative rotation between the first electrical connector and the first end in a loosened state, and restricts relative rotation between the first electrical connector and the first end in a tightened state.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is an LED lamp module utilizing high power LEDs that is ideal for installation in conventional traffic signal lamps. Moreover, the present invention provides an improved connection mechanism for installing a retrofit LED lamp engine in a housing which physically restricts full rotation of an LED light engine.

InFIG. 2a, a schematic of an LED retrofitted cobrahead luminaire in accordance with the present invention is provided. As illustrated, such a cobrahead luminaire comprises an LED light engine300, an LED array305, a lens310, incoming AC lines320, a cobra housing330, a reflector340, and a lamp socket350. InFIG. 2b, a schematic of an LED retrofitted shoebox luminaire is also provided. Within this embodiment, the shoebox luminaire comprises an LED light engine400, an LED array405, a lens410, incoming AC lines420, a shoebox housing430, a reflector440, and a lamp socket450. Details of connection mechanisms in accordance with the present invention for each of these two types of luminaires are summarized below.

FIG. 3ashows a schematic cross section of one embodiment of a connection mechanism in accordance with the present invention. Within such embodiment, an LED light engine500further comprises a flanged end510with an electrical connector from the LED light engine500. Flanged end510electrically connects to a first end of a retrofit threaded screw-in electrical connector530. The second end of electrical connector530then connects to the original housing lamp socket550of the luminaire.

A sleeve560having a flanged end561and a threaded end562is used to secure the mechanical and electrical connection between LED light engine500and electrical connector530. As illustrated inFIG. 3a, threads531and532are provided on opposite ends of electrical connector530. The threads532on the first end of connector530mate with the threads562of sleeve560. By tightening sleeve560against the threads on connector530, the flange end561of sleeve560grabs the flanged end510of LED light engine500.

It should be noted that if tightening sleeve560is in a tightened state, the frictional force between LED light engine500, connector530, and sleeve560will restrict rotation (unless the rotational force exceeds the breaking point force of either LED light engine500, connector530, or sleeve560). For LED light engines that cannot be fully rotated in a housing, such a tightening mechanism is an improvement over the prior art. And although the present invention does allow for LED light engine500to rotate relative to connector530while in a loosened state, the extent to which this relative rotation is needed is minimal. Moreover, while the present invention allows for LED light engine500to be finely rotated for alignment purposes while in a loosened state, the prior art requires full rotation in order for LED light engine500to be securely connected to the desired housing.

In an alternative embodiment, threads601may also be placed on the near side of LED light engine600as shown inFIG. 3b. Such an arrangement is a reverse of the mechanism described inFIG. 3a, wherein flange610is now located at the first end of connector630. Accordingly, by tightening sleeve660against the threads601of LED light engine600, the flanged end661of sleeve660grabs flange610at the first end of connector630. The second end of electrical connector630then connects to the original housing lamp socket650of the luminaire.

In another embodiment illustrated inFIG. 3c, electrical connector730comprises an indented hollow cavity720at its first end. Such an embodiment is similar to the embodiment described inFIG. 3aexcept for the existence of indented hollow cavity720. Thus, flange710is again located on the near end of LED light engine700, and threads732are again located on the first end of connector730. Here, however, flange710further comprises a male end which mates with cavity720when sleeve760is tightened. The second end731of electrical connector730then again connects to the original housing lamp socket750of the luminaire.

In yet another embodiment illustrated inFIG. 3d, the first end of connector830comprises both indented hollow cavity820and flange810. Such an embodiment is similar to the embodiment described inFIG. 3cexcept for the existence of threads801on the end of the LED light engine. Moreover, as sleeve860is tightened here, threads801on the near end of LED light engine800mate with threads862on sleeve860, and a male end of LED light engine800mates with cavity820. The second end831of electrical connector830then connects to the original housing lamp socket850of the luminaire.

In each of the above embodiments, it should be appreciated that various ways could be used to arrange the electrical contacts between the retrofit LED light engine unit and the screw-in electrical connector.FIG. 4a, for example, shows the rear end of a screw-in electrical connector930comprising a ring contact910of first polarity and an axial contact920of second polarity. In another embodiment as illustrated inFIG. 4b, connector1030comprises a pair of half ring contacts,1010and1020, which respectively provide a first and second polarity. In yet another embodiment shown inFIG. 4c, connector1130comprises two round contact regions,1110and1120, having a first and second polarity, respectively, as. And instead of using round contact regions, connector1230may also use square contacts,1210and1220, as shown inFIG. 4d.

When the LED retrofit light engine unit is too heavy for the strength of the existing lamp socket mechanical structure, an adaptor or similar equipment could be used to help secure the LED retrofit unit onto the luminaire, as illustrated inFIG. 5a. As illustrated, an adaptor1300is used to hold the retrofit LED light engine unit1310onto the front window rim1320of a cobrahead luminaire using the clips1330with a clip screen1340equipped for the cobra lens. It should, however, be appreciated that some cobrahead housings are equipped with screws1340instead of clips1330to hold the front lens as shown inFIG. 5b.

The present invention addresses the need for a high power LED lamp module that fits inside a conventional traffic signal lamp reflector, and which facilitates a fast and simple retrofit thereof. The advantages of the present invention are particularly apparent in housings which physically restrict full rotation of an LED light engine. And although several embodiments have been described, it is to be understood that the present invention is not limited to these embodiments, but rather encompasses any and all variations falling within the scope of the appended claims.