Patent Publication Number: US-6666704-B2

Title: Easily removable and attachable mechanical/electrical coupling

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority from U.S. Provisional Application Ser. No. 60/257,152 filed Dec. 22, 2000. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to couplings for mechanically supporting and electrically connecting electronic devices. The present invention has particular applicability to quick connect/disconnect devices for electronic equipment designed for use at one of multiple possible locations. 
     BACKGROUND ART 
     Certain electronic equipment, such as flat-panel monitors used in airplanes for business and entertainment purposes, is removably mounted so that it can be stowed for take-off and landing, and is electrically attached to a powered receptacle as desired by the user. Typically, an airplane is equipped with several such powered receptacles at different locations. To facilitate connection and disconnection of such electronic equipment, a device known as a “hot plug arm” has been employed which comprises a plug that mates with the permanently mounted powered receptacles to electrically connect the equipment and to provide mechanical support for the equipment. Hot plug arms typically also comprise a pivotable arm attached to the plug to allow the user to adjust the viewing position of the monitor. 
     Conventional hot plug arms provide simultaneous electrical and mechanical connections to the powered receptacle; in other words, when the plug of the hot plug arm is inserted into the receptacle so that the arm and the equipment mounted to it is securely supported, an electrical connector in the plug mates with a corresponding connector in the receptacle at the same time. Consequently, electrical power cannot be disconnected while the hot plug arm is plugged into the receptacle and is mechanically supporting the monitor. Since monitors typically do not have an on/off switch, this situation is problematic because it does not allow the user the flexibility of turning off the monitor without removing it from the receptacle and stowing it. To overcome this problem, a non-standard monitor with an on/off switch is sometimes provided. However, the limited availability and extra cost of such monitors renders this solution less than ideal. 
     There exists a need for a hot plug arm capable of supporting a monitor without providing power to the monitor. 
     SUMMARY OF THE INVENTION 
     An advantage of the present invention is a hot plug arm that allows removal of power from a piece of equipment, such as a monitor, attached to it without removal of the hot plug arm/monitor assembly from the receptacle into which it is plugged. 
     According to the present invention, the foregoing and other advantages are achieved in part by an apparatus comprising a first electrical connector portion; a second electrical connector portion for engaging with the first electrical connector portion to establish an electrical connection; a receptacle for mounting the first electrical connector portion; and a plug for engaging the receptacle such that the receptacle and plug form a substantially rigid coupling when engaged. The plug comprises a housing for mounting the second electrical connector portion, and the housing is movable from a first position where the first and second electrical connector portions are disengaged to a second position where the first and second electrical connector portions are engaged. 
    
    
     Additional advantages of the present invention will become readily apparent to those skilled in this art from the following detailed description, wherein only the preferred embodiment of the present invention is shown and described, simply by way of illustration of the best mode contemplated for carrying out the present invention. As will be realized, the present invention is capable of other and different embodiments, and its several details are capable of modifications in various obvious respects, all without departing from the invention. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Reference is made to the attached drawings, wherein elements having the same reference numeral designations represent like elements throughout, and wherein: 
     FIG. 1 a  is a cross-sectional view of an apparatus in accordance with an embodiment of the present invention. 
     FIGS. 1 b-c  are top and side views, respectively, of an apparatus in accordance with an embodiment of the present invention. 
     FIG. 2 is an exploded view of an apparatus according to an embodiment of the present invention. 
     FIG. 3 a  is a cross-sectional view of an apparatus in accordance with an embodiment of the present invention. 
     FIG. 3 b  is a side view of an apparatus in accordance with an embodiment of the present invention. 
     FIG. 4 a  is a cross-sectional view of an apparatus in accordance with an embodiment of the present invention. 
     FIG. 4 b  is a side view of an apparatus in accordance with an embodiment of the present invention. 
     FIG. 5 a  is a cross-sectional view of an apparatus in accordance with an embodiment of the present invention. 
     FIG. 5 b  is a side view of an apparatus in accordance with an embodiment of the present invention. 
     FIG. 6 a  is an exploded view of a locking mechanism in accordance with an embodiment of the present invention. 
     FIG. 6 b  is a top view of a locking mechanism in accordance with an embodiment of the present invention. 
     FIG. 6 c  is a cross-sectional view of a locking mechanism in accordance with an embodiment of the present invention. 
    
    
     DESCRIPTION OF THE INVENTION 
     Conventional hot plug arms for connection to a powered receptacle do not allow power to be disconnected from the electronic equipment carried by the arm without removing the hot plug arm from the receptacle. The present invention addresses and solves this problem of conventional plugs. 
     According to one embodiment of the present invention, a hot plug arm comprises a plug portion inside of which is slidably mounted a connector housing carrying an electrical connector half through which electrical signals may pass. The plug further comprises a lever for sliding the housing between an engagement position, in which the electrical connector half engages a mating electrical connector half in a receptacle, and a non-engagement position where the connector halves are apart. 
     The plug has retractable nubs on its exterior which engage grooves in the receptacle to retain the plug in the receptacle. Each of the nubs is biased outward to the engagement position by a spring-like backing plate attached to the nub disposed in the interior of the plug near the walls of the slidable housing. When the housing is in the non-engagement position, the nubs and their backing plates are allowed to retract with a modest force to allow the plug to be engaged with or removed from the receptacle. However, when the housing is slid via the lever to the engagement position, the housing walls prevent the nubs from retracting by abutting the backing plates. 
     Thus, the lever can be operated to engage or disengage the electrical connector halves when the plug and receptacle are engaged, without removing the plug from the receptacle. Furthermore, if the lever is operated to move the housing to the engagement position while the plug and receptacle are engaged, the plug cannot then be removed from the receptacle (since the nubs are locked in engagement with the grooves in the receptacle), thereby providing a positive locking function for the plug and receptacle. Still further, when the housing is in the engagement position and the plug and receptacle are apart, the plug cannot be inserted into the receptacle, because the nubs do not retract to allow insertion, thereby preventing inadvertent electrical connection. 
     An embodiment of the present invention will now be described in detail with reference to FIGS. 1 a - 5   b . As shown in FIGS. 1 a-c , a hot plug arm according to this embodiment of the present invention comprises a male plug  100  having an electrical connector portion  101 , such as a male electrical connector. Plug  101  is removably engageable with a female receptacle  200  having a second electrical connector portion  201 , such as a female electrical connector, which is engageable with male electrical connector portion  101 . A hollow shaft  300  is rigidly attached to plug  200  at one end and is pivotably connected to an elongated member  400  at its other end. Elongated member  400  is generally tubular and pivotably connected at one end to a mounting structure  500  for an electronic device, such as a flat-panel monitor (not shown). Elongated member  400  and shaft  300  are configured to allow an electrical cable to be connected to connector portion  101  to pass through their respective interiors from the electronic device. The inventive hot plug arm can also include additional elongated structures (not shown) pivotally mounted between the distal end of elongated member  400  and mounted structure  500 . Receptacle  200  is rigidly attachable to a base structure (not shown), such that when plug  100  and receptacle  200  are engaged, they form a coupling for supporting shaft  300 , elongated member  400 , mounting structure  500  and the monitor. 
     Referring now to FIGS. 2,  3   a ,  3   b  and  4   a , receptacle  200  comprises a pair of opposing walls  200   a , each wall  200   a  having a recess  200   b , which alternatively can be a through-hole as shown in FIG. 3 b . Plug  100  comprises a plug body  102  having a pair of opposing walls  102   a  which are slidable between receptacle walls  200   a  to engage plug  100  and receptacle  200 , and substantially abut receptacle walls  200   a  when plug  100  and receptacle  200  are engaged. Plug body opposing walls  102   a  each have an aperture  102   b  proximal to their bottom end corresponding to a receptacle wall recess  200   b , and a nub  103  attached to a flat spring  104  mounted to the inside surface of wall  102   a  such that nubs  103  are biased to protrude through apertures  102   b . Springs  104  allow nubs  103  to retract, thereby allowing plug  100  and receptacle  200  begin to engage, and springs  104  allow nubs  103  to engage receptacle wall recesses  200   b  when plug  100  and receptacle  200  are fully engaged (as shown in FIG. 4 a ). Thus, nubs  103  act to maintain engagement of plug  100  and receptacle  200 . Further mechanical stability is provided for the coupling of plug  100  and receptacle  200  by a substantially vertical pin  200   c  mounted in receptacle  200 , which fits into a hole in a substantially vertical wall  102   d  in plug body  102 . 
     Plug  100  further comprises a housing  105 , to which male connector portion  101  is mounted, having a pair of opposing walls  105   a  slidable between plug body opposing walls  102   a . Opposing walls  105   a  each have an aperture  105   b  and a retainer  106 , such as a plastic spring, biased to protrude through aperture  105   b . Retainers  106  engage recessed portions  102   c  of plug body opposing walls  102   a  to retain housing  105  in a first position within plug body  102  where connector portions  101  and  201  are disengaged, as depicted, for example, in FIG. 4 a . A lever  107  is provided for moving housing  105  within plug body  102 , lever  107  being pivotably mounted to plug body  102  at a first end  107   a , as by screws  108 , and pivotably mounted to the housing&#39;s opposing walls  105   a  between first end  107   a  and a second end  107   b , as by pins  109 . Lever  107  is used to slide housing  105  within plug body  102  between the first position described above and shown in FIG. 4 a  to a second position where connector portions  101  and  201  are engaged, as depicted in FIG. 5 a . More particularly, when housing  105  is in the first position and lever  107  is pushed downwards, retainers  106  retract to allow housing  105  to slide to the second position. 
     When the user desires to couple plug  100  and receptacle  200 , lever  107  is pulled upward, as shown in FIG. 3 b , such that retainers  106  engage recessed portions  102   c  of plug walls  102   a  and housing  105  is in the first position (see FIG. 3 a ). Plug body  102  is then inserted into receptacle  200  until nubs  103  engage recesses or slots  200   b  (see FIG. 4 a ). At this point, plug body  102  and receptacle  200  are mechanically coupled and support the monitor via elongated member  400 , but the monitor is not electrically connected. Next, lever  107  is pushed down, retainers  106  retract, housing  105  moves to the second position, and connector portions  101 ,  201  mate to provide an electrical connection to the monitor (see FIGS. 5 a-b ). Of course, lever  107  can be pulled up to separate connector portions  101  and  201  and terminate the electrical connection, while plug  100  and receptacle  200  remain coupled. 
     As shown in FIG. 5 a , when housing  105  is in the second position, housing walls  105   a  abut springs  104  proximal to nubs  103 , preventing nubs  103  from retracting. Consequently, plug  100  and receptacle  200  cannot be disengaged when housing  105  is in the second position. This feature of the present invention provides a positive lock for the plug/receptacle coupling. Likewise, when plug  100  and receptacle  200  are apart, as shown in FIGS. 3 a  and  3   b , and housing  105  is in the second position (or in any position except the first position), housing walls  105   a  prevent nubs  103  from retracting, thereby preventing plug body  102  from being engaged with receptacle  200 . This feature of the present invention prevents inadvertent electrical connection between connector portions  101  and  201 , since plug  100  and receptacle  200  must first be physically connected prior to an electrical connection being established. 
     Next, with reference to FIGS. 3 b ,  4   b ,  5   b  and  6   a - 6   c , a locking device will be described for positively retaining housing  105  in the second position. The locking device is for engaging lever  107  for substantially immobilizing lever  107  when lever  107  is operated to move housing  105  to the second position. The locking device comprises a push button locking member  601  on lever  107  that incorporates a slot  601  a for engaging a hook  610  attached to plug body  102  for locking lever  107  in the “down” position. A spring  602  between locking member  601  and lever  107  biases locking member  601  towards engagement with hook  610 . Plate  603  retains spring  602  and locking member  601  in place on lever  107 . A sloped surface  601   b  on locking member  601  and a corresponding sloped surface  610   a  on hook  610  allows locking member  601  to move out of the way to engage hook  610  when lever  107  is pushed down (see FIG. 6 c ). Once hook  610  and locking member  601  are engaged, the bias of spring  602  forces slot  601   a  of locking member  601  under hook  610 , locking lever  107  in place. To release lever  107 , locking member  601  is pushed towards the centerline of plug body  102 , allowing slot  601   a  to clear hook  610  and permit raising of lever  107 . 
     The present invention is applicable to various types of hot plug arms, particularly those for removably mounting electronic equipment such as flat screen monitors for use on airplanes. 
     The present invention can be practiced by employing conventional materials, methodology and equipment. Accordingly, the details of such materials, equipment and methodology are not set forth herein in detail. In the previous descriptions, numerous specific details are set forth, such as specific materials, structures, chemicals, processes, etc., in order to provide a thorough understanding of the present invention. However, it should be recognized that the present invention can be practiced without resorting to the details specifically set forth. In other instances, well known processing structures have not been described in detail, in order not to unnecessarily obscure the present invention. 
     Only the preferred embodiment of the present invention and but a few examples of its versatility are shown and described in the present disclosure. It is to be understood that the present invention is capable of use in various other combinations and environments and is capable of changes or modifications within the scope of the inventive concept as expressed herein.