Patent Publication Number: US-7708578-B1

Title: Misalignment tolerant connector

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This application is a continuation of U.S. patent application Ser. No. 12/177,107 filed Jul. 21, 2008, which claims the benefit of U.S. Provisional Application No. 60/961,311, filed Jul. 19, 2007, the entire contents of which are hereby incorporated by reference herein. 

   TECHNICAL FIELD 
   Embodiments of the present invention are in the field of Electrical Connectors and, in particular, Tolerant Connectors for Solar Cells. 
   BACKGROUND 
   Environmentally sealed electrical connectors are widely used in a number of applications to exclude moisture and/or dirt, which could otherwise lead to shorting of a set of coupled connectors to ground or to another electrical circuit or could degrade the quality of the electrical connection. One application for environmentally sealed electrical connectors, for example, is to electrically couple arrays or modules of photovoltaic cells, commonly known as solar cells, to a power distribution network. Typically, an environmentally sealed electrical connector includes a flexible member, such as a polymer O-ring or boot, which is fixed to one of a pair of mating halves of the connector and sealingly engages the other half when the connectors are joined or mated. 
   One problem with existing environmentally sealed electrical connectors is that the flexible member may interfere with the proper orientation and coupling of the two halves of the connector. This is particularly problematic in applications such as electrically coupling solar modules, where one or both halves of the electrical connector are covered by the module being coupled to the electrical circuit or where one or both halves of the connector is not hand-accessible, making the proper orientation and insertion of one half of the electrical connector into another even more difficult. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1A  is a schematic block diagram of a cross-sectional side view of a first mating half of an environmentally sealed electrical connector, in accordance with an embodiment of the present invention. 
       FIG. 1B  is a schematic block diagram of a cross-sectional side view of a second mating half of an environmentally sealed electrical connector, in accordance with an embodiment of the present invention. 
       FIG. 2  illustrates a cross-sectional view representing a situation where the plug assembly and the socket assembly of an electrical connector for a photovoltaic module are misaligned in a blind setting. 
   

   DETAILED DESCRIPTION 
   A misalignment tolerant connector is described herein. In the following description, numerous specific details are set forth, such as material regimes, in order to provide a thorough understanding of embodiments of the present invention. It will be apparent to one skilled in the art that embodiments of the present invention may be practiced without these specific details. In other instances, well-known fabrication techniques, such as molding techniques, are not described in detail in order to not unnecessarily obscure embodiments of the present invention. Furthermore, it is to be understood that the various embodiments shown in the Figures are illustrative representations and are not necessarily drawn to scale. 
   Reference in the description to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of the phrase “in one embodiment” in various places in the specification do not necessarily all refer to the same embodiment. 
   Described herein is an electrical connector having a plug assembly and a socket assembly. The plug assembly may include a plug body and an outer barrel with an inner conductive receptacle electrically coupled to a first conductor in the plug body. In one embodiment, an elastomeric tip is disposed at the end of the outer barrel. The socket assembly may include a socket body movably held within an outer housing by a positioning ring, the socket body having a socket barrel with a second conductor fixed therein to be received in the conductive receptacle of the plug assembly. In one embodiment, the second conductor is electrically coupled to a third conductor through a flexible conductor extending from the socket body through the positioning ring. The plug assembly and the socket assembly may include alignment features to align the conductive receptacle and the second conductor during coupling of the socket assembly and the plug assembly. In one embodiment, the elastomeric tip of the plug assembly is provided to effect a compression fit in the socket barrel. In a specific embodiment, at least one of the plug assembly and the socket assembly is coupled with a photovoltaic module. 
   An electrical connector may be fabricated to have a high degree of tolerance to misalignment between separate, uncoupled mating halves of the connector. Furthermore, the electrical connector may be fabricated to be environmentally sealed upon mating of the halves of the connector. Thus, in accordance with an embodiment of the present invention, an environmentally sealed electrical connector is provided having a high tolerance to misalignment between uncoupled halves of the connector. In an embodiment, the plug assembly and the socket assembly include features, such as conical surfaces on the plug and socket bodies, to align the conductive receptacle of the plug assembly and the fixed conductor of the socket body during coupling of the assemblies. In an embodiment, the electrical connector further includes a ratcheting locking feature to secure the socket assembly and plug assembly in a coupled position. 
   In an aspect of the present invention, an electrical connector having a plug assembly and a socket assembly is provided.  FIGS. 1A and 1B  are schematic block diagrams of a cross-sectional side view of mating halves of an environmentally sealed electrical connector, in accordance with an embodiment of the present invention. Referring to  FIGS. 1A and 1B , an electrical connector includes a plug assembly  102  and a mating socket assembly  120 . Plug assembly  102  and socket assembly  120  include alignment features to align the assemblies during the coupling or mating thereof. 
   Referring to  FIG. 1A , plug assembly  102  includes a plug body  104  and an outer barrel  106  which has an inner conductive receptacle  108  that is electrically coupled to a first conductor  110 . In accordance with an embodiment of the present invention, plug body  104  and outer barrel  106  are composed of a hard dielectric material such as, but not limited to, a hard thermoplastic. In one embodiment, outer barrel  106  further includes a rounded elastomeric tip  112  that at least partially surrounds conductive receptacle  108 . In a specific embodiment, as depicted in  FIG. 1A , conductive receptacle  108  further includes a positive contact feature  114  such as, but not limited to, a raised flexible conductive element or spring to ensure electrical contact between conductive receptacle  108  and a fixed conductor or pin from a socket assembly inserted therein. 
   Referring to  FIG. 1B , socket assembly  120  includes a socket body  122  movably held within an outer housing  124  by a compliant positioning ring  126 . In accordance with an embodiment of the present invention, outer housing  124  is composed of a material such as, but not limited to, a metal or a hard dielectric material (e.g., a hard thermoplastic, having the desired mechanical properties). In an embodiment, positioning ring  126  is composed of a number of metal or thermoplastic springs, or of an elastomeric material or foam as depicted in  FIG. 1B . Positioning ring  126  enables socket body  122  to move relative to outer housing  124  in a range of radial and angular motions while acting as a spring to center socket body  122  in its nominal resting position, concentric to outer housing  124 . In one embodiment, positioning ring  126  is held or adhered to socket body  122  such that socket body  122  cannot be separated therefrom by forces that would typically be encountered during coupling or de-coupling plug assembly  102  and socket assembly  120 . 
   In accordance with an embodiment of the present invention, socket body  122  is composed of a hard dielectric material such as, but not limited to, a hard thermoplastic and is recessed to include a socket barrel  128  with a fixed conductor  130  (e.g., a pin) protruding from a lower surface  132  of socket body  122 . Socket barrel  128  is sized and shaped to enable outer barrel  106  of plug assembly  102  to be inserted therein. In an embodiment, socket barrel  128  is sized and shaped to enable elastomeric tip  112  on the end of outer barrel  106  of plug assembly  102  to engage and seal with an inner surface  134  of socket barrel  128  when plug assembly  102  and socket assembly  120  are joined. In one embodiment, elastomeric tip  112  of plug assembly  106  is provided to effect a compression fit in socket barrel  128 . As depicted in  FIG. 1B , fixed conductor  130  is positioned, sized and shaped to be received in conductive receptacle  108  of plug assembly  102  when socket assembly  120  and plug assembly  102  are joined or coupled. In an embodiment, fixed conductor  130  is electrically coupled to a second conductor  136  through a flexible conductor  138  extending from socket body  122  to outer housing  124  through a void  140  in positioning ring  126 . In a specific embodiment, fixed conductor  130  further includes an insulating tip guard  142 , as depicted in  FIG. 1B . In another specific embodiment, socket body  122  further includes weep holes  144  to substantially prevent accumulation of moisture in socket body  122 . For example, in an embodiment, weep holes  144  are disposed in socket assembly  120  for water vapor transfer away from fixed conductor  130 . 
   In accordance with an embodiment of the present invention, the alignment features of plug assembly  102  and socket assembly  120  operate to align conductive receptacle  108  and fixed conductor  130  of socket body  122  during coupling of the assemblies. In the embodiment depicted, the alignment features include a projecting, exterior conical surface  116  on plug body  104  and a recessed, interior conical surface  146  on socket body  122 . In one embodiment, plug assembly  102  and socket assembly  120  are misaligned when thrust together for coupling. As a result, lateral forces generated by outer barrel  106  or conical surface  116  of plug assembly  102  striking conical surface  146  of socket body  122  act to move or deflect socket body  122  held within outer housing  124  by positioning ring  126 , thereby aligning fixed conductor  130  of socket body  122  relative to conductive receptacle  108  of plug assembly  102 . In accordance with an embodiment of the present invention, an electrical connector further includes a locking feature to secure socket assembly  120  and plug assembly  102  in a coupled position. For example, in one embodiment, the locking feature includes a ratcheting mechanism having a pair of tangs or pawls  148  on socket assembly  120  that engages sloped teeth  118  of plug body  104 , as depicted in  FIG. 1B , and to allow for a range of coupled positions. 
   In an aspect of the present invention, in operation, when plug assembly  102  is inserted approximately axially to socket assembly  120  but is somewhat misaligned, plug assembly  102  causes socket body  120  to move radially and angularly by imposing a force on conical surface  146  of socket body  122 . This force may guide elastomeric tip  112  of plug assembly  102  towards socket barrel  128 . Upon the tip of plug assembly  106  reaching socket barrel  128 , the design is such that socket barrel  128  and the tip of plug assembly  106  are nominally aligned. As the tip of plug assembly  106  enters socket barrel  128 , positioning ring  126  compensates for any remaining misalignment. Fixed conductor  130  and conductive receptacle  108  are designed such that there is a range of positions that are suitable to make a good electrical connection, thus compensating for situations where fixed conductor  130  cannot be fully inserted into conductive receptacle  108 . In an embodiment, positive contact feature  114  enables the functioning of a range of positions that are suitable to make a good electrical connection. In one embodiment, elastomeric tip  112  substantially seals the electrical connection over a range of insertion positions. In an embodiment, locking features on plug assembly  106  and socket assembly  120 , if present, are designed to engage over a range of insertion positions. 
   In an aspect of the present invention, a misalignment tolerant connector enables the positioning of photovoltaic modules in such a manner as to minimize the gaps between modules and the base on which they rest, as well as minimize the gaps between modules. In one embodiment, both types of gaps are minimized in order to maximize the area of a photovoltaic array relative to the area of a roof or support structure, e.g. for optimal energy capture, and to minimize the vertical space consumed by the modules. Such close spacing of photovoltaic modules may also improve aesthetics. However, in one embodiment, because modules are closely spaced to each other and the mounting surface, it is often laborious to make electrical connections between modules and extra cabling must be provided to allow connections to be made by hand. Thus, designs that allow for electrical connections to be easily made are desirable because they eliminate the need for hand connections, and also eliminate extra cabling that adds material cost, is subject to damage, and can be unsightly. 
   However, because the modules are spaced so closely together, the point at which electrical connections are made is often visually obscured. In order to make reliable electrical connections “blind,” the connectors must be capable of tolerating and correcting misalignment during the mating process.  FIG. 2  illustrates a cross-sectional view representing a situation where the plug assembly and the socket assembly of an electrical connector for photovoltaic modules are misaligned in a blind setting. Referring to  FIG. 2 , an electrical connector is composed of a plug assembly  202  in a frame  204  coupled to a photovoltaic laminate  206 . A socket assembly  208  is housed in a frame  210  coupled to another photovoltaic laminate  212 . A first cable  214  is coupled to plug assembly  202  and a second cable  216  is coupled to socket assembly  208 . As depicted in  FIG. 2 , plug assembly  202  and socket assembly  208  are misaligned. However, in accordance with an embodiment of the present invention, plug assembly  202  has a structure similar to the structure of plug assembly  102  and socket assembly  208  has a structure similar to the structure of socket assembly  120 , both of which are described above in association with  FIG. 1 . In one embodiment, an electrical connection can still be made between plug assembly  202  and socket assembly  208 , even though they are misaligned. 
   Thus, an electrical connector having a plug assembly and a socket assembly has been described. In accordance with an embodiment of the present invention, the plug assembly includes a plug body and an outer barrel with an inner conductive receptacle electrically coupled to a first conductor in the plug body. An elastomeric tip is disposed at the end of the outer barrel. The socket assembly includes a socket body movably held within an outer housing by a positioning ring, the socket body having a socket barrel with a second conductor fixed therein to be received in the conductive receptacle of the plug assembly. The second conductor is electrically coupled to a third conductor through a flexible conductor extending from the socket body through the positioning ring. The plug assembly and the socket assembly include alignment features to align the conductive receptacle and the second conductor during coupling of the socket assembly and the plug assembly. The elastomeric tip of the plug assembly is provided to effect a compression fit in the socket barrel. In a specific embodiment, at least one of the plug assembly and the socket assembly is coupled with a photovoltaic module. 
   Advantages of the electrical connector of the present invention over previous or conventional connectors include the ability to provide a reliable and environmentally sealed electrical connection under circumstances in which there may be significant, axial misalignment between the uncoupled halves of the connector. The connector is particularly advantageous for use in situations in which the connection is not hand-accessible. The inventive connectors are particularly useful for electrically connecting solar or photovoltaic modules to an electrical power grid or distribution network. Such an electrical connector may be used for module-to-module connections, series string connections, or to connect a module to a “bus” integrated in a mounting member, such as a rail.