Abstract:
The invention is an improved housing for storage of an electronics interface package. The housing is attached to a sensor adaptor or connector, and rotatable about that sensor adaptor. The interface package is contained in the interior of the housing, and is orientatable in the interior to provide different angles of view.

Description:
[0001]    This application claims the benefit of provisional application for patent Ser. No. 61/138,004 filed on Dec. 16, 2008, which is incorporated by reference herein in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Many field processes use sensors located within the process environment, such as level sensors. These sensors are generally directly mounted in a tank or process line, or a portion of a sensor mounted to the outside of a tank that works in conjunction with a portion of the sensor in the tank (such as a magnetic level sensor that operates in conjunction with a magnetic float in the tank). The sensors are electrically connected to an electronic interface package which is stored in a housing to protect the electronics from the ambient environment. In a direct mount package, the sensor protrudes from the tank, and the housing mounts via a sensor adaptor or connector to the sensor. In other applications, a cable may be routed from the sensor through conduit to the housing holding the electronics. Power is generally provided to the housing as required for operation of the sensor and electronics. The housing may need to be mounted in a particular configuration, for instance, at the top of a process tank, at the bottom of a process tank, on the side of the process tank or offset from the process tank by a desired angle. See  FIG. 11 . Many sensor interface packages include components that provide manual interaction with the sensor at the housing, such as a visual indicator of the sensor readings (display screen or an alpha numeric display), or an input apparatus (such as a keypad or cable plug) to operate the sensor in manual mode, enter a calibration sequence, or invoke other functionality. When the sensor interface package includes such interactive components, the housing must be orientable to allow the user to access or view the interactive components. The most common manner to provide the needed degree of housing orientation is to have a separate housing model or construction for each needed orientation or installation. Shown in  FIG. 11  is multiple orientations for the housing/sensor package, including sensor  100  (here a long probe), the housing  110 , and a connector  120  between the housing and sensor. As shown in  FIG. 11   a - j , multiple mounting configurations are possible, but many require a different housing model to provide for bottom mount, top mount, or left/right side mount. The manufacturer will typically assemble and ship the unit as a package (sensor/housing/connector) based upon the customer&#39;s ordered configuration, to keep the unit&#39;s inner electronics being unnecessarily disturbed by the customer. 
         [0003]    The need to account for multiple mounting orientations requires that the manufacturer stock multiple models of the housing/adapter. Stocking multiple embodiments for the housing is inefficient. As can also be seen in  FIG. 11 , the housing  110  includes a view window  130  to allow an operator to view or operate the interactive components in the housing, such as a display. As can be seen, the orientation of that window  130  can be right-side up, upside down, left or right facing (e.g. sideways), depending on the mounting configuration. This makes viewing the display, for instance, difficult. 
       SUMMARY OF THE INVENTION 
       [0004]    The invention is an improved housing for storage of an electronics interface package. The housing is attached to a sensor adaptor or connector, and rotatable about that sensor adaptor. The interface package is contained in the interior of the housing, and is orientatable in the interior to provide different angles of view. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]      FIG. 1  is a perspective view of one embodiment of the housing 
           [0006]      FIG. 2  is a side cross section through the housing of  FIG. 1 . shows a cross section through one embodiment of the housing of the present invention. 
           [0007]      FIG. 3  is a cross section through the housing, but a perspective of the corresponding connector. 
           [0008]      FIG. 3  detail is a view of  FIG. 3  showing an alternative embodiment. 
           [0009]      FIG. 4A  is a perspective view of the housing showing the interior of the module compartment with an L shaped member installed in the compartment. 
           [0010]      FIG. 4B  is a perspective view of the housing showing the interior of the module compartment with an electronic module holder installed in the compartment. 
           [0011]      FIG. 5A  is a side view of the electronic module holder. 
           [0012]      FIG. 5B  is a bottom view of the electronic module holder. 
           [0013]      FIG. 6A  is a perspective view of one embodiment of an electronic module top. 
           [0014]      FIG. 6B  is a bottom view of an electronic module base. 
           [0015]      FIG. 6C  is a perspective view of one embodiment of a module puller. 
           [0016]      FIG. 7  is a cross section through the module compartment showing the installed components. 
           [0017]      FIG. 8A  is a perspective view of one embodiment of viewing glass cover for the module compartment. 
           [0018]      FIG. 8B  is a perspective view of one embodiment of a glass cover retainer ring 
           [0019]      FIG. 8C  is a cross section through one embodiment of a viewing glass cover for the interface electronic module compartment. 
           [0020]      FIG. 9  is a perspective view of the interior of the terminal compartment. 
           [0021]      FIG. 10  is a cartoon depicting movement of the wiring in the interface component. 
           [0022]      FIG. 11  is a front view of several prior art mounting orientations of housing/sensor/connector. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0023]    Shown in  FIG. 1  is a prospective view of one embodiment of the housing. The housing body will generally be formed from cast stainless steel or aluminum, if used as an explosion proof housing, or it may be formed from a cast rigid plastic material that is non-reactive with the environment otherwise. As shown, the housing includes a body  1  that contains an interior that is partitioned into two compartments, an module compartment  10 , and a terminal compartment  30 . The two compartments are preferred but are not necessary. A single compartment could be used if the module compartment contained a terminal strip or a matching plug or socket to accommodate incoming wiring, sockets or plugs, or other cable connector. 
         [0024]    As shown in  FIG. 1 , both compartments have an opening that may be closed with removable covers  11  and  31 . As depicted in the housing cross section of  FIG. 2 , the module compartment  10  and terminal board compartment  30  are stacked, one above the other, with the two openings into the compartments orientated at an angle of about 75 degrees to each other. Other angles may be used depending of the specific housing design. A first channel  21  connects the two compartments, while a port  22  provides for entry into the module compartment. Terminal compartment  30  includes one or more ports  23  providing wiring access to the terminal compartment via attachable conduit to the port  23 . 
         [0025]    Removably mating with the housing  1  is a sensor connector  50  (shown in  FIG. 3 ). As shown sensor adapter is hollow right angle tube that is threadable into port  22  in the housing. The sensor connector  50  may be a straight connector or a connector formed with any desired angle. The sensor will generally directly attach to the sensor connector at opening  53  (such as a sensor top threading into opening  53 ). Alternatively, a conduit may be attached to opening  53  and be routed to the sensor  100 . In any event, wiring will operationally connect the sensor with equipment located in the housing (such as the module, later described). Located at the opposite end of the sensor connector  50  is an upstanding finger  51 . As shown, upstanding finger  51  projects upwardly from the rim of the threads  50 A. When the sensor adapter  50  is threaded into the port  22 , the finger  51  projects into module compartment  10  or is adjacent the interior of the module compartment  10 . The sensor connector  50  also has a slot  50 . 1  to accommodate a sealing ring, such as an “O” ring. A set screw may be used through housing  1  to contact and set the degree of rotation of the sensor connector  50  with respect to the housing  1 . However, because the fit of the sensor connector  50  to the housing  1  is designed to be a tight fit, a set screw, clamp or other means to fix the position of the sensor connector may not be required. 
         [0026]    As shown in  FIG. 4 , positioned on the bottom of the module compartment  10  are stops  13 . Rotatably mounted to the bottom of the module compartment on cylinder  14  is “L” shaped stop bracket  15 . Stop bracket  15  has a center opening to slide over cylinder  14 . Stop bracket  15  may be retained in place on cylinder  14  with a snap ring or other suitable retaining device (such as the module mount next described). The end of the stop bracket  15  includes a projecting finger  15 . 1  that couples with finger  51 . As shown, the stops  13  are angled to accommodate the movement of the stop bracket  15  and provide stops to the bracket at a desired angle of bracket movement or rotation. In use, the sensor connector  50  is first threaded into the housing  1  and the stop bracket  15  next installed. After installation of the stop bracket  15 , the sensor connector  50  may rotate with respect to the housing  1  until finger  51  contacts finger  15 . 1 , further rotation of sensor connector (or relatively, the housing) will rotate stop bracket  15  until bracket  15  contacts stop  13 . In this fashion, the housing is allowed to rotate with respect to the sensor connector through a fixed angular range, here through a range slightly greater than 360 degrees. Alternatively, the interior wall of the port  22  may have a downwardly projecting insertable finger (e.g. snap inserted in a corresponding groove) that interfaces with a rotatable ring inserted into a circumferential groove in the interior of the sensor connector—the rotatable ring would have an upstanding finger that interfaces with the port finger, providing almost 360 degrees of relative rotation (not shown). 
         [0027]    As described, the interaction of the sensor connector finger  51  with the bracket  15  and stops  13  creates a means to allow rotation of the sensor connector within a fixed range, here the range is slightly in excess of 360 degrees. The movable stop bracket allows a minimum of one full 360 degree rotation. Other means to allow rotation of the sensor connector with respect to the housing, within a fixed range, may be employed. For instance the sensor connector  50  may have a finger  50 . 3  projecting from the base of the connector adjacent the housing exterior (shown dashed in  FIG. 3  detail). The exterior of the housing could have a slot into which a downwardly projecting finger  50 . 2  may be inserted and fixed (such as by a screw, or snap-in). This downwardly projecting finger or stop bracket would be inserted after assembly, and act as a stop to the upward projecting finger. In this fashion, the rotational motion of the assembled sensor connector/housing may rotate through a fixed range of about 360 degrees. The 360 degree rotation allows for great flexibility in setting the orientation of the housing/sensor for various mounting orientations, but no so great to allow wiring, for instance between the sensor and housing, to become tangled within the housing. Alternatively, a pivoting stop bracket and with stops may be mounted on the exterior of the housing and interface with a projecting finger such as finger  50 . 1  (the position of the finger and stop bracket may be interchanged), however, this is not preferred as the pivoting bracket is exposed to the external environment and may be damaged. 
         [0028]    As shown in  FIG. 4A , the inner sidewall of the compartment  10  contain detents or notches  55  located at various positions on the sidewall. Their functionality will be described later. Additionally inner sidewall has threads  54  to accommodate a cover. Threads could be on the outer sidewall, or another means of removably covering the opening into the compartment  10  could be used. 
         [0029]    Shown in  FIGS. 5A  &amp; B is module holder  40 . As shown, holder  40  is an “U” shaped arm. Located on the bottom of the arm are shown two inserts  42  (a single insert can be employed) to retain an electrical plug, connector or socket, and a hollow cylinder mount  43 . Additionally, coaxial cable connectors can be included in the arm. Module holder  40  is rotatably mounted in the chamber  10  by sliding cylinder mount  43  onto cylinder  14 , and may be secured to cylinder via screw (threaded into cylinder  14 ), a snap ring, or other retaining device. It is preferred that the module holder  40  be raised from the floor of the compartment  10  to accommodate wiring to be positioned between the rotatable module holder  40  and the floor of the compartment  10 , later described. For this reason, the cylinder  14  may be a “stepped cylinder” such as shown in detail  4 C. Each upstanding arm of the “U” shaped module holder  40  includes an outward facing finger or bump  44 , located on the arms at a height to fit into the notches  55  in the inner wall of the compartment  10  (a single arm may be so equipped, but it is preferred to use two arms, both so equipped). The arms are somewhat flexible, allowing the notches  55  and projecting fingers act as a “click stop” or detent mechanism to fix the location of the rotatable module holder  40  with respect to the housing. The inward facing surface of the upstanding arms contains a projecting finger or bump  47 , designed to interface a similarly positioned notch or depression in the module to retain the module in the module holder  40  in a click-lock arrangement. Obviously, the bumps and notches could be interchanged and accomplish the same result. Instead of bumps on the inner walls of the module holder&#39;s arms, the top of the module holder&#39;s arms may have inward projecting flanges designed to retain a module, next described. An alternative design is to have an outwardly projecting tab or ear at the top of each arm of the U shaped module holder (or only on one arm) (not shown). These tabs would ride on a ledge formed in the sidewall of the module compartment. The click stop arrangement of bumps and notches could be employed in the tab/ledge relationship, or alternatively, the ledge may have cutouts sized to accommodate the tab portion, so that as the tab rotates, it would fall into a corresponding cutout to lock the position of the module holder in the module compartment. All of these arrangements are considered a means to engage the module holder with the module compartment. The module holder may also comprise an “L” shaped holder, having only a single upstanding arm. 
         [0030]    Positioned onto module holder  40  is a electronic module  60  (see  FIG. 6 ). As shown in  FIGS. 6A and 6B , module includes a top  66 , and a base,  67 , and an electronics package that slides into the cover (not show). Module  60  will contain the electrical components to allow a user to interact with the sensor, and allow the sensor to interact with the module. The particular module  60  shown is designed to interface a level sensor, and contains a screen or alpha numeric display to display the sensors return signal. For this reason, module top  66  has a viewing window  61 , and interface buttons  62  to manually interact with the electronics in the module  60 , and plugs  62 . 1  to allow a user to interact via another plug-in instrument. Located on the bottom of the module ( FIG. 6B ) are one or two electrical connectors or sockets  65  (such as a male adapter) designed to interface a corresponding connector (such as a female adapter) positioned in the insert  42  on the module holder  40 . Two connectors are preferred, one to connect the module  60  with the sensor wiring, the other to connect the module  60  to the wiring from the terminal compartment. When the module  60  is positioned in the module holder  40 , the module  40  will snap into place in the holder  40 , aligning the plugs or pins  65  in the module  60  with plugs or pins positioned in the inserts  42  in the module holder  40 . Other arrangements of, or multiple connectors, may be used to fit the particular needs of the level sensor. This includes separate connectors for wireless antennas or a special communications link, for example. 
         [0031]    As shown in  FIG. 6A , the module  60  has two lengthwise slots  69  to accommodate the arms of the module holder  40 . Slots have notches  69 . 1  to accommodate the fingers or bumps on the module holder&#39;s arms. Also shown are two lengthwise channels  68 . Sliding in each of these channels is a module puller  90  (see  FIG. 6C ). Module pullers  90  have a projecting stop  92  that will retain the bar  90  in the channel  68 , preventing upward removal of the bar. Module pullers  90  are use to assist removal of a module  60  installed in the module holder  40 , when positioned in the compartment  10 . To remove a module  60 , the module pullers  90  are slid upwardly until the stop  92  catches on the module cover  66 . Further upward force on the module pullers  90  will overcome the click stop frictional arrangement between the module holder&#39;s arms and compartment sidewalls, allowing removal of the module from the module holder. The module pullers  90  provide a grasping surface, and other mechanical means can be used, such as a grasp hook pivotably mounted to the module holder case, finger grip ridges molded in the module case, etc. 
         [0032]    It is preferred that the fit between the module holder  40 , the module  60 , and compartment  10  chamber be close, so that the insertion of the module  60  into the holder  40  will force the fingers or bumps  44  of the holder&#39;s arms into the notches  55  in the compartment wall, thereby fixing the position of the interlocked module  60  and module holder  40  with respect to the compartment  10 . Further rotation of the module/holder is thus prevented. In this arrangement, the module holder, module and housing are locked into a desired position, and any change of this relationship requires removal of the module  60  from the holder  40 . 
         [0033]      FIG. 7  is a cross section through the housing showing the relationship of the assembled parts. A cover  70  is then put over the opening in the compartment  10 , thus enclosing the components therein. If an explosion proof arrangement is not needed, the cover may simply be a retaining ring threaded or snapped onto or into the top of the compartment  30  opening, thus allowing the user to view and interact with the module. 
         [0034]    The module holder as described is locked into a desired orientation by the click stop or detent relationship between the module holder  40  and inner sidewalls of the compartment  10 . Other mechanical means may be used to accomplish this task. For instance, the module top  66  may have a ridges that snap into channels in the sidewall of the compartment  10  (or vice versa) in an interlocking arrangement, such as a dovetail-type joint. These channels in the sidewall may be placed at various locations on the sidewall, for instance, at 15 degree intervals, to permit the module to snap in place at various orientations (0 degrees, 15 degrees, 30 degrees, etc.). In this arrangement, the module holder  40  may be dispensed with. A sufficient length wiring harness (attached to the module or the compartment) may be employed to electrically connect the module and compartment wiring, and allow the module to be removed form the compartment before disconnecting the wiring. For instance, the module may incorporate one or two plugs that connect with matching plugs or blocks in the housing, with a sufficient length of cable attached to the plugs to allow the module to be removed, and then unplugged. Alternatively, each ridge in the module cover may include a plug that snaps into place in a matching plug located in the corresponding sidewall channel (each channel preferably having such a plug to allow for different orientations of the module in the compartment). Alternatively, the module may have a series of pins positioned on the module bottom, where each pin is positioned to touch one of a series of annular conductors mounted on a fixed plate (e.g. a flat slip ring disk) in the compartment bottom (of vice versa, e.g., the bottom of the module cover has positioned a series of annular conductors, etc). Alternatively, other slip ring or commentator arrangements may be employed between the module and a module holder. The above embodiments provide the ability to position the module at a selected orientations within the module compartment. The cooperation of the module with module compartment, or the module holder with the module compartment, provides a means to fix the position of the module in the module compartment at a select one of several positions. This “means” thus allow the user to set and fix the position of the module in the module compartment at a desired orientation. 
         [0035]    Compartment  30  may be closed by a blank cover since this compartment does not typically provide any display for the user. For an explosion proof housing, it is preferred that cover for compartment  10  include a glass window to provide a view port in the cover  70 . A preferred window cover is shown in cross section in  FIGS. 8A , B, and C. Cover  70  includes an annular ring  71 , with an opening therethrough. The ring is threaded, and has a top rim  75  to retain a glass insert  72 . Positioned between top rim surface and glass  72  is an “O” ring  73 . “O” ring  73  is retained in a circular channel cut in the underside of the ring  71  top. The inside sidewall of the ring  71  also has a grooves  78 . 1  into the side wall to accommodate the flats  77 . 1  of the locking ring  77  (next described). A channel(s) in the sidewall  76  enters the bottom portion of the grooves. The channel  76  may be circumferential, or each groove  78 . 1  will have an associated short channel  76  exiting the bottom of the groove  78 . 1  to accommodate the flats  77 . 1  of the locking ring in a locked position. 
         [0036]    Locking ring  77  may be similar to an open snap ring, or be a closed circular ring  77 . The locking ring  77  depicted in  FIG. 8B  is a closed ring and includes projecting flats  77 . 1 , and cutouts  77 . 2 . To install, the locking ring flats  77 . 1  are aligned with the corresponding grooves  78 . 1 , the locking ring  77  is slid down the interior sidewall  78  of the outer ring  70  until the locking ring is even with channel  76 , and then the locking ring is rotated, placing the ring flats  77 . 1  in the channel  76  or short channels  76 , thereby by retaining the locking ring  77  in ring  71 . The locking ring&#39;s outer diameter is smaller then the inner diameter of the ring  71 , leaving a gap  79  between the locking ring  77  and inner sidewall  78  of the ring  71 . After the cover  70  is assembled, epoxy  80  may be easily inserted (such as by a syringe though this gap  79 ) between the glass  72 , the inner sidewall  78 , and the top rim  75 . This epoxied fit is needed to comply with standards set by the International Electrotechnical Commission (IEC) for explosion proof standards, particularly IEC 60079-1, hereby incorporated by reference. The cutouts  77 . 2  are used to manipulate an installed ring. Projecting flats  77 . 1  may be inclined at a slight angle with respect to the locking ring  77  to help retain an installed ring in the channel. 
         [0037]    The cover may have internal threads or external threads to intermate with suitably positioned threads on the housing. The threadable join is needed for explosion proof housings, but other means of attaching a cover, know to those of skill in the art, may be used in a non-explosion proof embodiment. The locking ring shown is a completely closed ring, however, the locking ring may be a snap ring with projecting flats. If a snap ring is used as a locking ring, the grooves  78 . 1  in the sidewall may be dispensed with, as the locking ring can be compressed to allow the projecting flats  77 . 1  to clear the sidewall  78  when installing. Alternatively, the channel  76  may be dispensed with and the grooves  78 . 1  retained, in which event the snap ring should have sufficient expansive force, when installed, to force the flats in a tight relationship in the grooves  76  to retain the snap ring. 
         [0038]    Another embodiment includes a two piece snap ring comprising two co-planar inner and outer rings, offset from each other by a gap, and joined together at discrete intervals. The outer ring is sized to be insertable into the channel  76  in the sidewall  78  of the cover, and the inner ring is sufficiently offset from the outer ring so that the gap between the inner/outer rings is adjacent the sidewall of the cover, thereby providing the needed space for injection of epoxy adjacent the glass. With this dual ring embodiment, the projecting flanges are not needed. The interior of the terminal compartment  30  is detailed in  FIG. 9 . Two ports  23  allow access to the interior of this compartment, while channel  21  allows wiring to be passed from this compartment to the module compartment. As shown, this compartment has a raised flat flange  32 , on which a semicircular terminal block, circuit board or wafer board may be attached. Wiring (such as for power and communications) is brought into the terminal compartment through ports  23  (generally through a single port). One of the ports may be used for a mounting an antenna to allow for wireless communications. Wiring from the board (or from the outside through port  23 ) travels into the module compartment via port  21  to provide power/communications to the electronic module in the module compartment. Generally, once the wiring is in place between the two compartments, the port  21  will be filled with sealant or epoxy to environmentally isolate the two compartments. In a single compartment design, (i.e. no terminal compartment), wiring (such as power) would be brought directly into the module compartment, either through port  22 , of via a port positioned as needed into the module compartment. 
         [0039]    Because the module may rotate slightly over 360 degrees, it is necessary to accommodate the internal wiring in the module compartment  20  to allow for rotation of the module. Shown in  FIG. 10  is the module compartment  10 , with center cylinder  14 . The module holder  44  is shown dashed. Also shown are the inserts  42  on the module holder into which the electrical connectors are positioned. The wiring  100  connects to the electrical connectors in the inserts  42 . Wiring  100  is preferably a ribbon type cable with sufficient length within the chamber to accommodate the movement of the electrical connector in the links  42 . A round cable or cable bundle may also be employed, and posts in the floor of the module compartment may be used to guide cable movement. For an explosion proof housing, the cover  70  should include the sealing features disclosed the provisional application entitled “Explosion Proof Housing Cover Seal” application No. 61/122,958 filed on Dec. 16, 2008 (hereby incorporated by reference).