Abstract:
A power line disconnect apparatus includes a housing; an electrical connector that projects from a surface of a connector plate coupled to the housing, the electrical connector configured to receive a plug of a power cable; an ejector pin configured to project through a first aperture in the connector plate and eject the plug from the electrical connector; a microswitch configured to activate and deactivate a power circuit associated with the power cable; and a sensor pin configured to project through a second aperture in the connector plate, the sensor pin having a sensor pin extension, the sensor pin extension configured to control the microswitch.

Description:
TECHNICAL FIELD 
     This disclosure is directed generally to electrical connections and more particularly to a power line auto-disconnect apparatus for use with an electrical power connection. 
     BACKGROUND 
     Emergency vehicles (such as fire trucks and ambulances), recreational vehicles, and power boats, often utilize power lines that are connected to stationary power sources for supplying electrical power for starting engines, charging batteries, and other purposes. However, such vehicles may need to uncouple swiftly from the power line when they are to be driven away in response to an emergency, or the like. Consequently, the mating power line plug should eject on activation of the vehicle&#39;s engine, and also should eject in a manner that reduces or eliminates drawing an arc between the plug and the vehicle connector. Arcing, if not suppressed, is a major source of wear on contacts in both the vehicle connector and the plug. It is this wear that significantly reduces the service life of these components. 
     SUMMARY 
     This disclosure provides a power line auto-disconnect apparatus for use in an electrical power connection. 
     In a first embodiment, a power line disconnect apparatus includes a housing; an electrical connector that projects from a surface of a connector plate coupled to the housing, the electrical connector configured to receive a plug of a power cable; an ejector pin configured to project through a first aperture in the connector plate and eject the plug from the electrical connector; a microswitch configured to activate and deactivate a power circuit associated with the power cable; and a sensor pin configured to project through a second aperture in the connector plate, the sensor pin having a sensor pin extension, the sensor pin extension configured to control the microswitch. 
     In a second embodiment, a vehicle includes an engine and a power line disconnect apparatus attached to a surface of the vehicle. The power line disconnect apparatus includes a housing; an electrical connector that projects from a surface of a connector plate coupled to the housing, the electrical connector configured to receive a plug of a power cable; an ejector pin configured to project through a first aperture in the connector plate and eject the plug from the electrical connector; a microswitch configured to activate and deactivate a power circuit associated with the power cable and the vehicle; and a sensor pin configured to project through a second aperture in the connector plate, the sensor pin having a sensor pin extension, the sensor pin extension configured to control the microswitch. 
     Other technical features may be readily apparent to one skilled in the art from the following figures, descriptions, and claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of this disclosure and its features, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  shows an external perspective view of an auto-disconnect apparatus for use in an electrical power connection, according to this disclosure; 
         FIG. 2  shows a perspective view of the auto-disconnect apparatus of  FIG. 1  from another angle; 
         FIG. 3  shows another perspective view of the auto-disconnect apparatus of  FIG. 1 ; 
         FIG. 4  shows yet another perspective view of the auto-disconnect apparatus of  FIG. 1  from a different angle; 
         FIG. 5  shows a side section view of the auto-disconnect apparatus of  FIG. 1  with a plug connected to the auto-disconnect apparatus; and 
         FIG. 6  illustrates an electrical schematic diagram of the auto-disconnect apparatus of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     The figures, discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of this disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any type of suitably arranged device or system. 
     As described above, some vehicles—particularly emergency vehicles—may need to quickly uncouple a connected power line when the vehicles are to be driven away in response to an emergency, or the like. Consequently, the mating power line plug should eject on activation of the vehicle&#39;s engine, but also it must eject in a manner that reduces or eliminates drawing an arc between the plug and the vehicle. Arcing, if not suppressed, is a major source of wear on contacts in both the vehicle connector and the plug. It is this wear that significantly reduces the service life of these components. 
     To address these and other issues, embodiments of this disclosure provide a power line auto-disconnect apparatus that includes a sealed housing on which an electrical connector is mounted. Typically, the power line auto-disconnect apparatus is mounted (or otherwise coupled) to a sidewall or other body portion of an emergency vehicle (e.g., a fire truck or ambulance), a recreational vehicle, or a power boat. During use, the electrical connector mates with an electrical plug that is part of a shore cable. Once connected, the shore cable is electrically coupled to an engine starting circuit or battery on the vehicle. Voltage that is applied to the starter when the engine is cranked is also applied to a solenoid in the automatic power line disconnect apparatus. The solenoid operates an ejector mechanism which is mounted in the housing. The ejector mechanism ejects the shore cable from the apparatus, and a switch that is mounted in the housing interrupts the current prior to the completion of the ejection action, thereby preventing arcing at the connector contacts and assuring long contact life. 
       FIGS. 1 through 5  illustrate various views of an auto-disconnect apparatus  100  for use in an electrical power connection, according to this disclosure. The embodiments of the auto-disconnect apparatus  100  illustrated in  FIGS. 1 through 5  are for illustration only. Other embodiments could be used without departing from the scope of this disclosure. 
       FIG. 1  shows an external perspective view of the auto-disconnect apparatus  100 . The auto-disconnect apparatus  100  includes a housing comprising a front housing  102  and a rear housing  104 . A part of the housing (e.g., the front housing  102 ) includes multiple wire ports  106 . Typically, there are two wire ports  106 , although in some embodiments there may be more or fewer wire ports  106 . As shown in  FIG. 1 , a plug  108  is engaged with the front housing  102  of the auto-disconnect apparatus  100 , concealing a male connector (which is shown in  FIG. 4  as the male connector  404 ). The plug  108  is at the end of a shore cable  110 . The plug  108  and the shore cable  110  are not part of the auto-disconnect apparatus  100 . 
     The auto-disconnect apparatus  100  is typically coupled to a vehicle  112  (e.g., mounted to a sidewall of the vehicle  112 ) and electrically coupled to a battery charger or other device on the vehicle  112  that requires alternating current power. The auto-disconnect apparatus  100  may include one or more mounting or attachment components (e.g., brackets, fasteners, mounting holes, and the like) to secure the auto-disconnect apparatus  100  to the vehicle  112 . 
       FIG. 2  shows a perspective view of the auto-disconnect apparatus  100  from another angle with the rear housing  104  removed and the front housing  102  shown in transparent view. In  FIG. 2 , various internal components of the auto-disconnect apparatus  100  are visible, including a microswitch  202 , an ejector arm  204 , a support bracket  206 , a pin  208 , and tension springs  212 . 
     The microswitch  202  activates and deactivates a power circuit that includes the shore cable  110 , the auto-disconnect apparatus  100 , and the vehicle  112 , as described in greater detail below. When the microswitch  202  activates the power circuit, power can be supplied from the cable  110  through the auto-disconnect apparatus  100 , to the vehicle  112 . When the microswitch  202  deactivates the power circuit, no current flows from the cable  110  to the vehicle  112 . In some embodiments, the microswitch  202  includes three contacts: normally open (NO), normally closed (NC), and common (C). 
     One end of the ejector arm  204  is pivotally mounted on the support bracket  206  by means of the pin  208 . The ejector arm  204  makes contact with the ejector pin  210  at approximately a mid-point of the ejector arm  204 . The ejector pin  210  is configured to move longitudinally back and forth, as indicated by the dashed arrows. A pair of tension springs  212  (only one of which is visible in  FIG. 2 ) coupled to the second end of the ejector arm  204  provide continuous force on the ejector arm  204  and the ejector pin  210  in the direction of the plug  108 . 
       FIG. 3  shows a perspective view of the auto-disconnect apparatus  100  with both the front housing  102  and the rear housing  104  removed. In this view, it can be seen that the microswitch  202  includes a microswitch arm  302 , one end of which is connected to and selectively activates and deactivates the microswitch  202  in response to movement of the microswitch arm  302 . The microswitch arm  302  extends away from the microswitch  202  and, at the end of the microswitch arm  302 , makes contact with a sensor pin extension  304 . The sensor pin extension  304  is fixedly coupled to and extends laterally outward from a sensor pin  402 , which is not visible in  FIG. 3 , but can be seen in  FIGS. 4 and 5 . The sensor pin  402  is configured to move longitudinally within a sensor pin guide  306 , in a direction of movement that is substantially parallel to the movement of the ejector pin  210 , as indicated by the dashed arrows in  FIG. 5 . The sensor pin guide  306  is generally cylindrical and fixedly secured inside the auto-disconnect apparatus  100 . The sensor pin guide  306  constrains and guides the movement of the sensor pin  402 . The sensor pin guide  306  also includes a side opening  308  that extends through and longitudinally along a wall of the sensor pin guide  306 . The sensor pin extension  304  protrudes from the sensor pin  402  through the side opening  308  and extends to make contact with the microswitch arm  302 , as shown in  FIG. 3 . 
       FIG. 4  shows another perspective view from a different angle of the auto-disconnect apparatus  100  with both the front housing  102  and the rear housing  104  removed. In this view, the plug  108  is not coupled to the auto-disconnect apparatus  100 . Without the plug  108 , it can be seen that the auto-disconnect apparatus  100  includes the sensor pin  402  and a male connector  404 . The male connector  404  extends outside of the front housing  102  so as to be visible from the exterior. Of course, in some embodiments, the male connector  404  may be protected by a cover that is moveable to reveal the male connector  404 . A connector plate  406  is coupled to the front housing  102  and surrounds the male connector  404 . The sensor pin  402  and the ejector pin  210  pass through respective apertures of the connector plate  406 . The sensor pin  402  is spring loaded to be biased in an outward position, such as shown in  FIG. 4 . The male connector  404  is configured to engage with a female connector at the end of the plug  108 .  FIG. 5  shows a side section view of the auto-disconnect apparatus  100  with the plug  108  connected to the auto-disconnect apparatus  100 . When connected, the male connector  404  and the plug  108  form an electrical connection for electrical current to flow from the shore line  110  to the auto-disconnect apparatus  100  and to the vehicle  112 . Typically, the electrical current is provided at 110V or 220V, although any suitable electrical source at any suitable voltage could be used. 
     As shown in  FIG. 4 , the contacts of the male connector  404  are significantly longer than the projection of the sensor pin  402 . However, the exposed portion of the ejector pin  210  is longer than the contacts of the male connector  404  when the ejector pin  210  is fully extended outward. In one aspect of operation, as the plug  108  is inserted for engagement with the auto-disconnect apparatus  100 , the plug  108  first makes contact with the ejector pin  210  and then with the contacts of the male connector  404 . As the plug  108  is inserted, the plug  108  pushes the ejector pin  210  inward and the female connector of the plug  108  slides over the contacts of the male connector  404 . The movement of the ejector pin  210  pushes the ejector arm  204  inward, against the force of the tension springs  212 . As the plug  108  is further inserted, the plug  108  contacts the sensor pin  402  and pushes the sensor pin  402  inward, while also continuing to depress the ejector pin  210 . The sensor pin  402  moves with the connected sensor pin extension  304 , which in turn depresses the microswitch arm  302  inward. When the plug  108  is fully engaged against the connector plate  406 , a trigger locks the ejector arm  204  into position. With the microswitch arm  302  depressed inward, the microswitch  202  and corresponding power circuit are activated to apply power from the plug  108  to the auto-disconnect apparatus  100  and to the vehicle  112 . Any electrical arcing that may result from the activation of the electrical current when the plug  108  is engaged with the auto-disconnect apparatus  100  would occur inside the microswitch  202 , which is constructed to absorb arcing occurrences. 
     Typically, when the shore cable  110  is plugged into the auto-disconnect apparatus  100 , the shore cable  110  will remain plugged in until the vehicle  112  is started. When the vehicle  112  is started (e.g., when the vehicle&#39;s engine is started), a solenoid (not shown) in the auto-disconnect apparatus  100  releases the trigger that frees the ejector arm  204  from its locked position. The tension springs  212  cause movement of the ejector arm  204  towards the plug  108 , which in turn causes the ejector arm  204  to advance the ejector pin  210  toward the plug  108 . This is turn pushes the plug  108  out, and decouples the plug  108  from the male connector  404  and the auto-disconnect apparatus  100 . 
     In some similar auto-disconnect systems, if a shore cable is manually unplugged and the vehicle is not started, the current through the shore cable would continue to flow until the moment that the plug is disconnected from the auto-disconnect system. This situation could create an arc at the male connector and/or the plug, thereby shortening the life of the connectors. 
     To avoid such an occurrence, the auto-disconnect apparatus  100  uses the position of the sensor pin  402  and the sensor pin extension  304  to control the current into the auto-disconnect apparatus  100 . When the sensor pin  402  is depressed by the plug  108 , the sensor pin extension  304  presses on the microswitch arm  302 , thereby activating the power circuit, which applies power from the plug  108  to the auto-disconnect apparatus  100  and to the vehicle  112 . When the shore cable  110  is unplugged, as the plug  108  is decoupled from the connector plate  406 , the spring-biased sensor pin  402  moves outward and the connected sensor pin extension  304  moves with the sensor pin  402 . The movement of the sensor pin extension  304  causes the microswitch arm  302  to move outward and causes the microswitch  202  and corresponding power circuit to be deactivated. This stops the current flow through the male connector  404 , the plug  108 , and the shore cable  110 . Because the full movement of the sensor pin  402  is less than the length of the contacts of the male connector  404 , the outward movement of the microswitch arm  302 , sensor pin extension  304 , and sensor pin  402  are completed (and thus the power circuit is interrupted) before the plug  108  is fully disengaged from the male connector  404 . This ensures that no arcing can occur at the male connector  404  and/or the plug  108 . 
     Because the sensor pin  402  and sensor pin extension  304  are not directly coupled to the ejector pin  210  or the ejector arm  204 , the movement of the pin  402  and extension  304  (and their control of the microswitch  202 ) is not dependent on the position of the ejector pin  210  or the ejector arm  204 . Stated another way, the control of the microswitch  202  and the power circuit are independent of the position of the ejector pin  210 . Thus, even if the plug  108  is manually removed and the ejector pin  210  is not released, the power circuit will still be interrupted before the plug  108  is completely removed. Thus, the potential for arcing at the male connector  404  and/or the plug  108  is negligible regardless of whether the plug  108  is manually removed or auto-ejected by the start of the vehicle  112 . 
       FIG. 6  illustrates an electrical schematic diagram of the auto-disconnect apparatus  100 . As shown in  FIG. 6 , the plug  108  includes neutral, line, and ground connections that are configured to couple with corresponding contacts in the male connector  404 . The microswitch  202  includes three contacts: normally open (NO), normally closed (NC), and common (C). The NC contact is not used in normal operation. A fault indicator  602  is connected to the NC contact. In some embodiments, if the plug  108  is inserted and a fault occurs in the power circuit of the auto-disconnect apparatus  100 , the fault indicator  602  will illuminate. A power indicator  604  is connected to the NO contact. When the plug  108  is inserted and the auto-disconnect apparatus  100  is operating correctly, the power indicator  604  will illuminate. In some embodiments, the fault indicator  602  and the power indicator  604  are LED lamps. However, any other suitable indicator could be used. 
     Although  FIGS. 1 through 6  illustrates one example of an auto-disconnect apparatus  100  for use in an electrical power connection, various changes may be made to the figures. For example, certain ones of the various components of the auto-disconnect apparatus  100  may be combined, rearranged, duplicated, separated into sub-components, or replaced with other components. 
     In some embodiments, various functions described above are implemented or supported by a computer program that is formed from computer readable program code and that is embodied in a computer readable medium. The phrase “computer readable program code” includes any type of computer code, including source code, object code, and executable code. The phrase “computer readable medium” includes any type of medium capable of being accessed by a computer, such as read only memory (ROM), random access memory (RAM), a hard disk drive, a compact disc (CD), a digital video disc (DVD), or any other type of memory. A “non-transitory” computer readable medium excludes wired, wireless, optical, or other communication links that transport transitory electrical or other signals. A non-transitory computer readable medium includes media where data can be permanently stored and media where data can be stored and later overwritten, such as a rewritable optical disc or an erasable memory device. 
     It may be advantageous to set forth definitions of certain words and phrases used throughout this patent document. The terms “application” and “program” refer to one or more computer programs, software components, sets of instructions, procedures, functions, objects, classes, instances, related data, or a portion thereof adapted for implementation in a suitable computer code (including source code, object code, or executable code). The terms “transmit” and “receive,” as well as derivatives thereof, encompass both direct and indirect communication. The terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation. The term “or” is inclusive, meaning and/or. The phrase “associated with,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, have a relationship to or with, or the like. The phrase “at least one of,” when used with a list of items, means that different combinations of one or more of the listed items may be used, and only one item in the list may be needed. For example, “at least one of: A, B, and C” includes any of the following combinations: A, B, C, A and B, A and C, B and C, and A and B and C. 
     While this disclosure has described certain embodiments and generally associated methods, alterations and permutations of these embodiments and methods will be apparent to those skilled in the art. Accordingly, the above description of example embodiments does not define or constrain this disclosure. Other changes, substitutions, and alterations are also possible without departing from the spirit and scope of this disclosure, as defined by the following claims.