Patent Publication Number: US-8540527-B2

Title: Jumper cable plug with moisture resistant seal

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is a continuation-in-part of U.S. patent application Ser. No. 13/022,629, filed Feb. 7, 2011 now U.S. Pat. No. 8,192,216, entitled JUMPER CABLE PLUG WITH MOISTURE RESISTANT SEAL, the contents of which are expressly incorporated herein in their entirety. 
    
    
     FIELD 
     The present invention relates to electrical plugs and sockets, such as, but not limited to, jumper cable plugs and sockets used to electrically connect jumper cables between and trailer and a tractor, truck, other trailer, etc. 
     BACKGROUND 
     Heavy duty trucks and tractor trailers typically involve a semi-trailer truck, or a tractor-trailer, having a trailer connected thereto. The trailer typically requires one or more electrical systems associated with turn signals, hazard signals, brake signals, braking systems, system monitoring, lighting, etc. These electrical systems are typically controlled or monitored from within the cab of the semi/tractor. Accordingly, an electrical connection is typically required between the semi/tractor and the trailer. Because the trailer is typically detachable from the semi/tractor, the electrical connection therebetween is also typically detachable. This detachable electrical connection typically takes the form of a plug-and-socket connection, wherein the socket may have one or more electrical connections (e.g., male pins) for mating with corresponding electrical connections (e.g., female terminals) of the plug. 
     A problem commonly associated with common plug-and-socket connections stems from moisture and debris reaching an interior of the socket cavity. The presence of moisture or debris may damage or corrode metallic connections, such as the electrical connections, which may in turn degrade or otherwise negatively effect the electrical connections between the semi/tractor and the trailer. 
     SUMMARY 
     Accordingly, there is a need for an improved jumper cable plug, wherein a moisture and debris resistant seal is formed when the plug is mated with a corresponding socket, thereby extending the useful life of the plug, the socket, and the electrical connections between the semi/tractor and the trailer. Although much of the following description describes jumper cable plugs and corresponding sockets, embodiments of the present invention may also take the form of other types of electrical plugs and corresponding sockets. 
     One embodiment of the present invention includes an electrical plug configured to be mated with a socket, the electrical plug including a substantially tubular plug housing having a front end, a rear end, a side wall between the front end and the rear end, and a housing protrusion on the side wall and configured to be inserted within a socket cutout of the socket, a groove proximate the front end of the housing, and a seal located in the groove and having a cross-section with an outer surface that is substantially similar to an outer surface of a cross-section of the side wall and the housing protrusion. 
     The plug may further include a substantially tubular electrical connection holder including a front, a rear, a side, and a connection holder protrusion on the side of the electrical connection holder, the housing may further include a housing cutout for accommodating the connection holder protrusion, and the electrical connection holder may be configured to be partially housed by the housing. 
     The electrical connection holder may further include a flange at the front of the electrical connection holder, the flange having an outer diameter approximately equal to an outer diameter of the housing, and the groove may be formed between the flange and the housing. 
     A portion of the connection holder protrusion may be within the groove, and the seal may have a seal cutout for accommodating the portion of the connection holder protrusion within the groove. 
     A portion of the side wall of the housing may define the housing protrusion and the housing cutout. 
     The side wall of the housing may have a first hole therethrough, wherein the side of the electrical connection holder has a second hole therein that is aligned with the first hole when the electrical connection holder is housed within the housing, and wherein the plug further includes a securing mechanism passing through the first hole into the second hole to fix the electrical connection holder to the housing. 
     The electrical connection holder may have a plurality of channels for receiving corresponding electrical terminals of the socket when the plug and the socket are mated. 
     Rotation of the electrical connection holder within the housing may be prevented when the connection holder protrusion is received by the housing cutout. 
     The housing protrusion and the socket cutout may ensure alignment of respective electrical connections of the plug and the socket when the plug and the socket are mated. 
     The plug may further include a pull tab on the housing. 
     A rear of the housing protrusion may be for engaging with a locking tab of the socket when the plug and the socket are mated. 
     The plug may further include a protuberance extending from the side wall of the housing farther than a front of the housing protrusion. 
     The seal and an interior of the socket may form a moisture resistant barrier when the plug is mated with the socket. 
     A portion of a rear of the seal may abut a front of the housing protrusion. 
     According to another embodiment of the present invention, there is provided an electrical plug configured to be mated with a socket, the electrical plug including a substantially tubular plug housing including a front end, a rear end, a side wall between the front end and the rear end, and a housing protrusion located on the side wall and configured to be inserted within a socket cutout of the socket, and a groove proximate the front end of the housing and configured to receive a seal having a cross-section with an outer surface that is substantially similar to an outer surface of a cross-section of a combination of the side wall of the housing and the housing protrusion. 
     The plug may further include a substantially tubular electrical connection holder in the front end of the housing, and the groove may be between a front of the electrical connection holder and the front end of the housing. 
     The electrical connection holder may include a connection holder protrusion, and the housing may have a housing cutout on an interior of the housing configured to receive the connection holder protrusion. 
     A portion of the connection holder protrusion may be in the groove. 
     The plug may further include a screw for securing the electrical connection holder to the housing. 
     The housing protrusion may be configured to be stopped by a locking tab on a lid of the socket that is configured to cover an opening of the socket when the plug and the socket are unmated. 
     Accordingly, embodiments of the present invention an improved jumper cable plug capable of reducing the presence of moisture and debris at the electrical connections by use of a moisture resistant seal. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a socket and a jumper cable plug (shown an unmated position) in accordance with one embodiment of the present invention; 
         FIG. 2  is a side elevational view of the plug and the socket (shown in the mated position) of the embodiment shown in  FIG. 1 ; 
         FIG. 3  is a cross-sectional view of the plug and the socket of  FIG. 2  taken along line  3 - 3 ; 
         FIG. 4  is a cross-sectional view of the plug and the socket of  FIG. 2  taken along line  4 - 4 ; 
         FIG. 5  is a perspective view of the plug of the embodiment shown in  FIG. 1 ; 
         FIG. 6  is a side elevational view of the plug of the embodiment shown in  FIG. 1 ; 
         FIG. 7  is a perspective view of a plug housing of the plug of the embodiment shown in  FIG. 1 ; 
         FIG. 8  is a perspective view of the plug housing of the plug of the embodiment shown in  FIG. 1 ; 
         FIG. 9  is a perspective view a seal ring in accordance with an embodiment of the present invention; 
         FIG. 10  is a plane view of the seal ring of the embodiment shown in  FIG. 9 ; and 
         FIG. 11  is a partial perspective view of the electrical connection holder and a front of the plug housing of the embodiment shown in  FIG. 5  with seal ring removed. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the present invention will now be described with reference to the figures, wherein like reference numerals represent like elements. Furthermore, for ease of description, reference to a “front” of a plug, socket, or a component thereof, shall generally refer to a portion that is most proximate a mating end of the plug or socket, while reference to a “rear” of a plug, socket, or component thereof, shall generally refer to a portion that is least proximate the mating end of the plug or socket. 
     Exemplary embodiments of the present invention are described with reference to  FIGS. 1-11  below. Plugs (e.g., jumper cable plugs) of the exemplary embodiments of the present invention, as well as sockets of the exemplary embodiments of the present invention, incorporate numerous aspects, and it should be noted that the present invention is not restricted to the exemplary embodiments, as various combinations of the described aspects may be made without departing from the spirit and scope of the present invention. 
       FIG. 1  is a perspective view of an electrical connection interface  10  of an embodiment of the present invention having a socket  12  and a jumper cable plug  14 , which are shown in an unmated condition.  FIG. 2  is an elevated view of the socket  12  and the plug  14  of the embodiment shown in  FIG. 1 , the socket  12  and the plug  14  shown in a mated condition. The plug  14  includes a plug housing  54  having a key  28 , an electrical connection holder/electrical terminal holder  64  partially housed by the housing  54 , and a seal ring  92  about the electrical connection holder  64  between the housing  54  and a front of the electrical connection holder  64 , the seal ring  92  having a shape allowing a rear of the seal ring  92  to conform to the front  66  of the housing  54  (shown in  FIGS. 7 ,  8 , and  11 ) including the key  28 . Accordingly, when the plug  14  is mated with the socket  12 , an outer portion of the seal ring  92  is brought in close contact with an interior  30  of the socket  12  to form a moisture resistant seal. 
     The plug  14  of the present embodiment includes a generally tubular/cylindrical housing  54 , while the socket  12  includes a wall  22  that defines a generally cylindrical cavity  20  for receiving the plug  14 , the cavity  20  being open at a front end of the socket  12 . The cavity  20  additionally includes a keyway  26  (e.g., a cutout) defined by an interior  30  of the wall  22  of the socket  12 . The keyway  26  is shaped to accommodate the key  28  (e.g., a protrusion/protuberance, which may be longitudinal) formed on a side of the housing  54  of the plug  14 . The key  28  may be integrally formed with the housing  54 . The keyway  26  and the key  28  allow proper orientation of the plug  14  and the socket  12  during mating of the plug  14  and socket  12 , and therefore also allow proper orientation of the electrical connections (e.g., male pins  36  and female terminals  38 , shown in  FIGS. 3-5 ) of the plug  14  and the socket  12 . Although the present embodiment depicts male pins  36  of the socket  12  and female terminals  38  of the plug  14 , other embodiments may include different arrangements, for example, wherein the plug comprises male terminals, and the socket comprises female terminals, or wherein electrical connections are made without pins and terminals. 
     The interior surface  30  of a socket barrel  16  of the socket  12  of the present embodiment includes a plurality of elongated ribs  42  that extend in a longitudinal direction of the socket  12  to facilitate drainage of moisture or water from the cavity  20 . In embodiments of the present invention, opposing ribs  42  may be provided on opposite sides of the interior surface  30  of the barrel  16  to ensure that the plug  14  remains properly spaced from interior surface  30 . However, other embodiments of the present invention may include an interior surface of a socket that does not include ribs  42 . 
     The socket  12  of the present embodiment includes one or more mounting holes  46  formed through a flange  40  of the socket  12  to facilitate mounting the socket  12  to an exterior wall of a semi/tractor or a trailer, although such mounting holes  46  are not necessary for the practice of invention. 
     The key  28  of the plug  14  of the present embodiment is formed on the plug housing  54  and extends longitudinally along the plug housing  54 . A rear of the key  28  of the present embodiment may also comprise an additional protrusion/protuberance  68 , which extends from the plug housing  54  further than a front of the key  28  (e.g., the protuberance  68  is thicker than the remainder of the key  28 ). Although the present embodiment includes the additional protrusion/protuberance  68  other embodiments of the present invention may include the key  28  without the additional protrusion/protuberance  68 , or with a differently located protrusion/protuberance. Furthermore, other embodiments may include differently shaped keys or key/protuberance combinations (such as a key that has a slope that evenly rises from front to back). 
     The socket  12  of the present embodiment may include a hinged lid  48  including a biasing member  34 , such as a torsional coil spring, to cause the lid  48  to cover an opening at the front of the cavity  20  when the socket  12  is unmated with the plug  14 . The lid  48  may further include a locking tab  52 , so that, while the plug  14  is mated to socket  12 , the biasing member  34  biases the lid  48  towards the plug  14  (e.g., towards an upper surface of the plug  14 ). The biasing member  34  causes the locking tab  52  to contact a surface of the housing  54  rearward of the protuberance  68  or the rear end of the key  28 , causing the locking tab  52  of the lid  48  to act as a stop by contacting the protuberance  68  or the key  28 , thereby reducing the likelihood of the plug  14  being inadvertently removed from the cavity  20  of the socket  12 . When the plug  14  is desired to be withdrawn from the socket  12 , the lid  48  may be lifted against the biasing force, allowing the protuberance  68  or the key  28  to clear the locking tab  52 . Although the locking tab  52  of the present embodiment is a part of the lid  48 , other embodiments of the present invention may include a differently located locking tab (e.g., on an interior of the socket). Although the protuberance  68  of the present embodiment extends from the housing  54  further than the key  28 , other embodiments of the present invention may include a key without an additional protuberance, which may be stopped by a locking tab of the socket when the plug and socket are mated. 
     The housing  54  may have an interior space  62 , and may include one or more pull tabs  76  that extend outwardly from the plug housing  54  to facilitate removal of the plug  14  from socket  12 , although other embodiments of the present invention may lack pull tabs  76 . The plug  14  of the present embodiment includes opposing pull tabs  76  adjacent a rear of housing  54  and extending from the sides of the housing  54 , allowing a user to remove the plug  14  from the socket  12  without pulling on the wires exiting the rear of the housing  54 , potentially damaging the electrical connection between the wires and the electrical terminals (e.g., female terminals  38 ) of the plug  14 . 
     Referring to  FIGS. 3-8  and  11 , the plug  14  of present embodiment also includes the electrical connection holder/electrical terminal holder  64  near a front end/portion  66  of the housing  54 . The electrical connection holder  64  of the present embodiment is configured to substantially block the opening at the front end  66  of the housing  54  by being inserted into the interior space  62  of the plug housing  54 . However, in other embodiments, the electrical connection holder  64  may be integrally formed with, or otherwise coupled to, the plug housing  54 . In the present embodiment, a screw  88  (shown in  FIG. 6 ) is configured to fix the electrical connection holder  64  in a stable position within the housing  54 . The electrical connection holder  64  of the present embodiment includes channels  70  of the plug  14  that match the pin pattern of the male pins  36  of the socket  12  and that are sized to receive metallic female terminals  38 . Other embodiments of the present invention may include more than one screw, or may secure the electrical connection holder  64  to the housing  54  by other means. 
     The electrical connection holder  64  of the present embodiment is generally cylindrical/circular, and has a flange  99  at a front of the electrical connection holder  64  that has a diameter that is slightly greater than a diameter of the rest of the electrical connection holder  64 . Accordingly, an annular groove  78  may be formed behind the flange  99 , between the front of the electrical connection holder  64  and the front portion  66  of the plug housing  54  (see  FIG. 11 ), such that the annular groove  78  may be within the socket cavity  20  when the plug  14  is mated with the socket  12 . In the present embodiment, a cross-section of the electrical connection holder  64  has a shape similar to that of the plug housing  54  and key  28 , although the size of the cross-section of the electrical connection holder  64  is smaller than that of the plug housing  54 . Accordingly, the shape of the groove  78  tracks the outer profile of the plug housing  54 /key  28 , and will similarly have a key  82  on a side of the electrical connection holder  64  and extending from the flange  99  (see  FIG. 11 ). The key  82  will correspond to a keyway  84  of the plug housing  54  located beneath the key  28 , and on an interior  62  of the plug housing  54  (e.g., a portion of the side wall of the plug housing  54  that defines the keyway  84  on the interior  62  of the housing  54  also defines the key  28  on the exterior of the housing  54 ). Accordingly, a cross-section of the interior  62  of the plug housing  54  of the present embodiment has a shape similar to, albeit having smaller dimensions than, a cross-section of the interior  30  of the socket  12 . Just as the plug  14  may be aligned with and inserted into the socket  12 , the electrical connection holder  64  may be aligned with and inserted into the plug housing  54 . 
     In this embodiment, because the key  82  of the electrical connection holder  64  extends from the flange  99  of the electrical connection holder  64  into the plug housing  54 , the key  82  is present at a portion of annular groove  78  (see  FIG. 11 ). The presence of the key  82  in the groove  78  is used to position and help retain the seal ring  92  within the annular groove  78 . Accordingly, and referring to  FIGS. 9 and 10 , the seal ring  92  of the embodiment shown in  FIGS. 1 ,  3 - 6 ,  9 , and  10  includes a corresponding recess  91  for receiving a portion of the key  82  of the electrical connection holder  64  proximate the flange  99 , and a cross-section of the seal ring  92  has a substantially uniform thickness that is slightly more than the depth of the groove  78  (e.g., slightly more than the width of the side wall of the housing  54 ). Because the groove  78  tracks the outer profile of the plug housing  54 , so does the seal ring  92 , wherein the outer profile of the seal ring  92  is slightly further from a central axis of the plug housing  54  than an exterior of the plug housing  54 . In other embodiments, protuberance  82  may be located in other positions of the groove  78 , with the corresponding keyway  84  of the housing  54  being correspondingly located. Further, more than one protuberance  82  and more than one corresponding recess in the seal ring  92  may be employed in other embodiments of the present invention. 
     The resilient seal ring  92  of the present embodiment has a width corresponding to that groove  78  in which it is located (e.g., the distance between a rear of the flange  99  of the electrical connection holder  64  and the front of the housing  54 ) so that the seal ring  92  may be received by the groove  78 . Further, the seal ring  92  has a cross-section of a shape and size that is substantially similar to that of the plug housing  54 , and has an interior contour that corresponds to the cross-sectional profile of the annular groove  78  so that the seal ring  92  can be tightly fitted around the electrical connection holder  64  between the flange  99  of the electrical connection holder  64  and the front  66  of the plug housing  54  within annular groove  78 . Because the seal ring  92  is seated within the groove  78 , and as shown in  FIGS. 2-4 , when the plug  14  is mated with the socket  12 , the resilient seal ring  92  will be positioned within the cavity  20 . 
     Although not required, embodiments of the present invention may utilize an adhesive to bond the seal ring  92  within the annular groove  78 . Alternatively, and according to other embodiments, instead of being adhesively bonded, the seal ring  92  may be over-molded onto the annular groove  78 , or may be co-molded with the electrical connection holder  64  so that the electrical connection holder  64  is injection molded around the seal ring  92 . Alternatively, if a material with a sufficient glass transition temperature is used, the seal ring  92  may be co-molded with the plug housing  54  so that the plug housing  54  is injection molded around the seal ring  92 . In this way, the seal ring  92  may provide features which improve the mechanical bonding between the seal ring  92  and plug housing  54 . 
     Referring to  FIGS. 9-10 , the resilient seal ring  92  of the present embodiment includes a base portion  93 , which seats in the annular groove  78  and a plurality of flexible ribs  94  integrally formed therewith. The flexible ribs  94  extend radially outward from the base  93  about its circumference. In the present embodiment, three flexible ribs  94  are provided, and the seal ring  92  (including the ribs  94 ) is made from a rubber material, such as EPDM rubber or silicone rubber, although other resilient materials can be used to make the resilient seal ring  92  in other embodiments. In other embodiments, other forms of seal rings may be employed. For example, a different number of ribs may be used. Furthermore, the seal ring  92  of the present embodiment includes a plurality of relief cuts  96  that are formed in the ribs  94  of the seal ring  92  and that are positioned and sized to align with and receive the ribs  42  of the socket  12  when the plug  14  and the socket  12  are mated, although other embodiments of the present invention may lack the relief cuts  96 . 
     When the plug  14  is inserted into the cavity  20  of the socket  12 , a substantially sealed internal volume  98  is formed due to the resilient seal ring  92 . Because the seal ring  92 , including the ribs  94 , is made of a generally resilient material, the seal ring  92  conforms to the profile of the interior surface  30  of wall  22  to form a water-resistant, if not water-tight, seal. Furthermore, by using a plurality of ribs  94  (e.g., three in the seal ring of the present embodiment), each rib  94  may form a separate seal with the interior  30  of the socket  12 , thereby providing redundant protection from moisture and debris. Therefore, when the plug  14  is mating with the socket  12 , the female terminals  38  of plug  14  and the male pins  36  of the socket  12  will be protected from moisture in the environment, thereby reducing the potential for corrosion that moisture and debris may cause. 
     While embodiments of the invention presented above have been shown and described as comprising a plug with female terminals so that a mating socket has male pins, it is within the scope of the invention for the electrical terminals to be reversed so that the plug has male pins and the mating socket has female terminals, or for the plug and the socket to have other electrical connections. If the plug  14  is constructed to comply with a particular SAE or ISO standard, then the plug  14  will mate with any socket that has also been constructed according to the standard. Thus, the plug  14  of the present patent document will provide water-resistant, if not water-tight seals when coupled to sockets used with existing trucks or trailers. 
     Furthermore, although the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that features of different embodiments may be combined to form further embodiments, and that various changes, modifications and adaptations in form and details of the invention are possible without departure from the spirit and scope of the invention. Thus the present invention has been described by way of illustration and not limitation, and is defined by the following claims and their equivalents.