Abstract:
An electronics module comprises an electronics assembly having a first connector and a second connector. The first and second connectors are disposed on opposite ends of the electronics assembly. A case encloses the electronics assembly. The first connector is accessible through a first side of the case and the second connector is accessible through a second side of the case. A locking tab is disposed on the case and is biased to an extended position. A sliding member is slidably coupled to the case and is operable to move the locking tab to a retracted position.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   Not applicable. 
   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
   Not applicable. 
   BACKGROUND OF THE INVENTION 
   The invention relates to methods and apparatus for retaining sub-components within an assembly. More specifically, embodiments of the invention are related to systems and apparatus for simplifying the installation and removal of an electronics assembly into a housing. 
   In oil and gas applications, flow computers are used for high-performance measurement and control functions, such as fiscal metering, custody transfer, batch loading, meter proving, multi-stream measurement, station monitoring/control and other applications. In order to provide flexible configurations and simplify maintenance, many of these flow computers utilize separate electronics modules to perform individual functions. Because a particular flow computer may only perform a limited number of functions, only those modules required to perform the needed functions are installed in the flow computer at a given time. 
   In order to provide a high level of configurability and customization, many flow computers are constructed so that the electronics modules can be easily changed or replaced. The electronics modules are often coupled to the flow computer by a retention system that supports field removal and replacement of electronics modules. Many of these retention systems utilize mechanical coupling mechanisms that require the use of a screwdriver, or other tool, to actuate. Many mechanical retention systems also take up valuable space within the flow computer housing, both for the retention system and for the space needed to provide tool access. In some instances the space needed for the retention system requires larger enclosures and system footprints. 
   Thus, the embodiments of the present invention are directed to methods and apparatus for retaining an electronics module that seek to overcome these and other limitations of the prior art. 
   SUMMARY OF THE PREFERRED EMBODIMENTS 
   Embodiments of the present invention include an electronics module comprising an electronics assembly comprising a first connector and a second connector. The first and second connectors are disposed on opposite ends of the electronics assembly. A case encloses the electronics assembly. The first connector is accessible through a first side of the case and the second connector is accessible through a second side of the case. A locking tab is disposed on the case and is biased to an extended position. A sliding member is slidably coupled to the case and operable to move the locking tab to a retracted position. 
   Other embodiments comprise an electronics block assembly comprising a backplane disposed within a housing. A sleeve is disposed within a receptacle in the housing. An electronics module is enclosed within a case that is insertable into the sleeve. A locking tab is disposed on the case and is biased to an extended position where the locking tab is engaged with the sleeves. A sliding member is slidably coupled to the case and operable to move the locking tab to a retracted position wherein the locking tab is not engaged with the sleeve. 
   Other embodiments include a method comprising disposing an electronics assembly within a case to form an electronics module. The case comprises a locking tab disposed on the case and biased to an extended position. A sliding member slidably coupled to the case and operable to move the locking tab to a retracted position. The method further comprises installing the electronics module into a sleeve disposed within housing, wherein the locking tab engages the sleeve when the locking tab is in the extended position. 
   Thus, the embodiments of the present invention comprise a combination of features and advantages that enable substantial enhancement of the installation and retention of electronics modules. These and various other characteristics and advantages of the present invention will be readily apparent to those skilled in the art upon reading the following detailed description of the preferred embodiments of the invention and by referring to the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a more detailed description of the present invention, reference is made to the accompanying Figures, wherein: 
       FIG. 1  is an isometric view of one embodiment of an electronics assembly constructed in accordance with embodiments of the invention; 
       FIG. 2  is a partial exploded view of the electronics block assembly of  FIG. 1 ; 
       FIG. 3  is a partial exploded view of select components of the electronics block assembly of  FIG. 1 ; 
       FIG. 4  is a partial sectional view of a portion of the electronics block assembly of  FIG. 1 ; 
       FIG. 5  is an isometric view of one embodiment an electronics module constructed in accordance with embodiments of the invention; 
       FIG. 6  is an isometric view of an electronics assembly constructed in accordance with embodiments of the invention; 
       FIG. 7  is an isometric view of a sliding member used with the electronics module of  FIG. 5 ; 
       FIG. 8  is an isometric view of a base used with the electronics module of  FIG. 5 ; 
       FIG. 9  is an isometric view of the sliding member of  FIG. 7  installed on the base of  FIG. 5 ; 
       FIG. 10  is a partial sectional view of an electronics module disengaged from a sleeve; 
       FIG. 11  is a partial sectional view showing the interaction of friction tabs and detents; 
       FIG. 12  is an isometric view of one embodiment of an electronics module constructed in accordance with embodiments of the invention; 
       FIG. 13  is a partial isometric view of the case of the electronics module of  FIG. 12 ; and 
       FIG. 14  is an isometric view of a sliding member used with the electronics module of  FIG. 12 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   In the description that follows, like parts are marked throughout the specification and drawings with the same reference numerals, respectively. The drawing figures are not necessarily to scale. Certain features of the invention may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in the interest of clarity and conciseness. 
     FIGS. 1 and 2  illustrate one embodiment of an electronics block assembly  10  that is used in a flow computer.  FIG. 2  shows a partially exploded view of block assembly  10 . Electronics block assembly  10  comprises housing  12 , backplane  14 , receptacles  16 , sleeves  18 , and electronic modules  20 . Support rack  22  couples backplane  14  to housing  12 . Backplane  14  comprises printed circuit board  24  having module connectors  26 , alignment holes  28 , accessory connectors  30 , and expansion connector  32 . Sleeves  18  are disposed within receptacles  16  of housing  12  and receive electronics modules  20 . Electronic modules  20  comprise an electronics assembly  34  disposed within case  36 . Electronics assembly  34  comprises external connectors  38  and internal connectors  40 , both of which are accessible through case  36 . 
   In certain embodiments, electronics assemblies comprise circuitry that provides high-performance measurement and control functions. External connectors  38  on the external end of module  40  and provide connection points for electrical leads and other components. For example, external connectors  38  may be a termination block that provides connection points for various sensors, meters, and other instrumentation. In general, these sensors and other instrumentation provide raw data to electronics assembly  34  and allow control signals to return to the connected equipment. The circuitry within electronics assembly  34  manipulates the raw data and converts the data into useful information for functions such as fiscal metering, custody transfer, batch loading, meter proving, multi-stream measurement, station monitoring/control. 
   When electronics modules  20  are disposed within sleeves  18 , internal connectors  40  are disposed within housing  12  and are engaged with module connectors  26  on backplane  14 . Backplane  14  interconnects the plurality of electronics modules  20  so as to allow communication between electronics assemblies  34  as well as provide a single location through which the information can be transmitted or communicated. 
   Housing  12  and electronics modules  20  are configured so as to simplify the connection of the electronics modules to backplane  14 . Therefore, block assembly  10  may include one or more features that aid in the alignment and engagement of electronics modules  20  with backplane  14 . In order to ensure that internal connectors  40  align with and engage module connectors  26 , sleeves  18  and electronics modules  20  comprise one or more alignment features. Referring now to  FIG. 3 , sleeve  18  comprises alignment pins  42 . When sleeve  18  is disposed within housing  12  (as shown in  FIG. 1 ), alignment pins  42  engage alignment holes  28  (see  FIG. 2 ) on backplane  14 . The interface of alignment holes  28  and pins  42  fixes the position of sleeve  18  relative to module connectors  26  (see  FIG. 2 ). Electronics module  20  further comprises key  44  that aligns with and engages slot  46  on sleeve  18 . Key  44  and slot  46  prevent module  20  from being installed in sleeve  18  in an incorrect orientation. 
   Block assembly  10  may also include one or more retention mechanisms that secure electronics module  20  to housing  12 . The retention system retains electronics module  20  within sleeve  18  of housing  12  but also allows for simple disengagement and removal of the module when desired. Components of the retention system can be seen in  FIG. 3  where case  36  of electronics module  20  comprises locking tab  48  that engages aperture  50  on sleeve  18 . The engagement of locking tab  48  and aperture  50  is shown in  FIG. 4 .  FIG. 4  also shows groove  52  on sleeve  18  engaging flange  54  of housing  12  in order to couple the sleeve to the housing. 
   Referring now to  FIG. 5 , electronics module  20  comprises electronics assembly  38  disposed within case  32 . Case  32  comprises base  54 , cover  56 , and sliding member  58 . One embodiment of electronics assembly  38  is shown in  FIG. 6  and comprises circuit board  60 , external connectors  38 , and internal connectors  40 . In certain embodiments, circuit board comprises processors and other electronic devices that process data that is transmitted through connectors  38  and  40 . 
   Sliding member  58  is shown in  FIG. 7  and comprises retention tabs  62 , locking tab ramp  64 , friction tab detents  66  and  67 , flange  68 , fill tabs  70 , and gripping surface  72 . Base  54  is shown in  FIG. 8  and comprises locking tab  48 , engagement member  74 , actuation cam  76 , friction tabs  78 , and key  44 . Sliding member  58  is assembled onto base  54  so that retention tabs  62  overlap and engage wall  80  on both sides of the base as shown in  FIG. 9 . Sliding member  58  can slide relative to base  54  from a first position to a second position. Retention tabs  62  fit within a slot located on cover  56  (not shown) when case  32  is assembled as shown in  FIG. 5 . The engagement of retention tabs  62  and the slot on cover  56  also limit the sliding movement of sliding member  58  as it moves from the first position to the second position. 
   Referring now to  FIG. 4 , sliding member  58  is shown in the first position where actuation cam  76  is disposed adjacent to ramp  64 . In the first position, locking tab  48  is in a position substantially flush with base  54  and engagement member  74  is fully extended from base  54 . With sliding member  58  in the first position, electronics module  20  can be inserted into sleeve  18 . As the angled leading edge of engagement member  74  contacts sleeve  18 , locking tab  48  will deflect inward. Once electronics module  20  is fully inserted into sleeve  18 , engagement member  74  aligns with aperture  50  and the bias of locking tab  48  will return the engagement member to its extended, first position. Thus, in the first position, engagement member  74  of locking tab  48  engages aperture  50  on sleeve  18  and retains electronics module  20  within the sleeve. In certain embodiments, surface  75  of engagement member  74  is tapered such that as electronics module  20  moves upward the engagement of aperture  50  and the tapered surface prevents the engagement member from dislodging from the aperture. 
   Sliding member  58  is shown in the second position in both  FIGS. 9 and 10 .  FIG. 9  shows the relationship between sliding member  58  and base  54 .  FIG. 10  is a partial sectional view illustrating the disengagement electronics module  20  from sleeve  18 . Sliding member  58  is moved from the first position to the second position (as shown in  FIG. 9 ) by sliding the sliding member relative to base  54 . As the sliding member  58  slides relative to base  54 , actuation cam  76  engages ramp  64 . The movement of actuation cam  76  along ramp  64  urges locking tab  48  inward into the interior of base  54 . This inward movement causes engagement member  74  to retract and disengage from sleeve  18  as is shown in  FIG. 10 . Once engagement member  74  is disengaged from sleeve  18 , electronics module  20  can be removed from the sleeve. When in the second position, fill tabs  70  are removed from sleeve  18  so as to allow electronics module  20  to move slightly relative to the sleeve in order to make removal easier. 
   Referring now to  FIG. 11 , friction tabs  78  and detents  66  and  67  give sliding member  58  a taught feel and provide a snap-action as a position indicator at both the first and second positions. When sliding member  58  is in the first position, friction tab  78  is disposed within detent  66 . As sliding member  58  is moved relative to base  54 , friction tab  78  deflects inward so that the tab disengages detent  66 . Once sliding member  58  reaches the second position, friction tabs  78  engages detent  67 . 
   Referring now to  FIG. 12 , electronics module  100  comprises electronics assembly  102 , case  104 , and sliding member  106 . Electronics assembly  102  is disposed within case  104  and comprises external connectors  108  and internal connectors  110 , both of which are accessible through case  104 . Sliding member  106  is preferably positioned off of the centerline of case  104 . The off-center positioning allows two adjacent electronics modules  100  to be placed in close proximity as their respective sliding members  106  would not interfere when the adjacent modules are positioned back-to-back. 
   Referring now to  FIG. 13 , sliding member  106  comprises slide tabs  112 , ramp  118 , and pull tab  120 . As shown in  FIG. 14 , case  104  comprises recessed area  122 . Locking tab  124  is disposed within recessed area  122  and comprises actuation cam  126 , stop member  128 , and engagement member  130 . Slots  132  allow slide tabs  112  to pass therethrough so that slide tabs  112  are engaged in groove  134 . 
   Sliding member  106  can slide relative to case  104  from a first position to a second position. In the first position, actuation cam  126  is disposed adjacent to ramp  118  in ramp aperture  136 . In the first position, locking tab  124  is in a position substantially flush with recessed area  122  and engagement member  130  is fully extended. Sliding member  106  is moved from the first position to the second position by sliding the sliding member relative to case  104 . As sliding member  106  slides relative to case  104 , actuation cam  126  engages and slides along ramp  118  until stop member  128  contacts the edge  138  of ramp aperture  136 . Stop member  128  and edge  138  act as a slide limiter to limit the movement of sliding member  106 . The movement of actuation cam  126  along ramp  118  deflects locking tab  124  inward into the interior of case  104  and retracts engagement member  130  into case  104 . 
   The preferred embodiments of the present invention relate to apparatus for connecting an electronic module to a block assembly. The present invention is susceptible to embodiments of different forms. There are shown in the drawings, and herein will be described in detail, specific embodiments of the present invention with the understanding that the present disclosure is to be considered an exemplification of the principles of the invention, and is not intended to limit the invention to that illustrated and described herein. 
   The embodiments set forth herein are merely illustrative and do not limit the scope of the invention or the details therein. It will be appreciated that many other modifications and improvements to the disclosure herein may be made without departing from the scope of the invention or the inventive concepts herein disclosed. Because many varying and different embodiments may be made within the scope of the inventive concept herein taught, including equivalent structures or materials hereafter thought of, and because many modifications may be made in the embodiments herein detailed in accordance with the descriptive requirements of the law, it is to be understood that the details herein are to be interpreted as illustrative and not in a limiting sense.