Abstract:
A memory module attaches as a component to a printed circuit board. An apparatus is disclosed for securing a memory module to a memory module socket. The apparatus includes a bracket device securely holding the memory module against the memory module socket. The memory module cannot disengage from the memory module socket without first removing the bracket.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This disclosure claims the benefit of U.S. Provisional Application No. 61/835,691 filed on Jun. 17, 2013 which is hereby incorporated by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to SODIMM memory modules. The disclosure particularly relates to a device for securing SODIMM memory modules in high shock and vibration environments while inserted into a SODIMM socket. The device can additionally provide an improved method of cooling the memory module. 
     BACKGROUND 
     The statements in this section merely provide background information related to the present disclosure. Accordingly, such statements are not intended to constitute an admission of prior art. 
     SODIMM memory modules are used throughout the computer industry in various applications. The most prevalent application would be in laptop computers. The current industry standard method of connecting and securing SODIMM modules is by way of the standard SODIMM sockets. There are applications where these modules are excluded because they do not meet high shock and vibrations requirements when used with SODIMM sockets. For that reason the majority of harsh industrial and military applications has declared the standard SODIMM socket to be unacceptable and will not allow them to be used in those types of applications. In those applications the industry requires that the individual memory chips must be soldered directly to the main PCB board to meet the shock and vibration specifications set forth by those perspective industries. 
     Standard SODIMM sockets incorporate a form of a spring clip to secure the device in the socket. It has been proven that the current method will not pass the requirements of high shock and vibration applications. 
     SUMMARY 
     A memory module attaches as a component to a printed circuit board. An apparatus is disclosed for securing a memory module to a memory module socket. The apparatus includes a bracket device securely holding the memory module against the memory module socket. The memory module cannot disengage from the memory module socket without first removing the bracket. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       One or more embodiments will now be described, by way of example, with reference to the accompanying drawings, in which: 
         FIG. 1  illustrates a typical memory module socket that is standard in the industry, in accordance with the present disclosure; 
         FIG. 2  illustrates an exemplary securing device installed to a memory socket and memory module, the securing device preventing the memory module from accidentally disengaging from the memory socket, in accordance with the present disclosure; 
         FIG. 3  illustrates in cross-section the components of  FIG. 2 , in accordance with the present disclosure; 
         FIG. 4  illustrates an alternative embodiment of a securing device including tabs for securing to locator cut-outs on either side of a memory module, in accordance with the present disclosure; 
         FIG. 5  illustrates an additional alternative embodiment of a securing device including heat dissipation fins, in accordance with the present disclosure; 
         FIG. 6  illustrates an additional alternative embodiment of a securing device in combination with layers of TIM, in accordance with the present disclosure; 
         FIG. 7  illustrates an additional alternative embodiment of a securing device including a pair of side brackets, in accordance with the present disclosure; 
         FIG. 8  illustrates an additional alternate embodiment of a securing device including a slotted frame bracket and leaving spring clips off of the memory socket, in accordance with the present disclosure; 
         FIG. 9  illustrates in cross-section the components of  FIG. 8 , in accordance with the present disclosure; 
         FIG. 10  illustrates the securing device of  FIG. 8  with a different memory socket maintaining spring clips, in accordance with the present disclosure; 
         FIG. 11  illustrates an alternative memory socket configuration including a first memory module and memory socket and a second memory module and memory socket, in accordance with the present disclosure; 
         FIG. 12  illustrates the memory socket configuration of  FIG. 11  in assembly view, in accordance with the present disclosure; 
         FIG. 13  illustrates an alternative memory socket configuration including alternative memory module, in accordance with the present disclosure; 
         FIG. 14  illustrates an additional alternative embodiment of a securing device including a pair of brackets, each bracket securing one spring clip, in accordance with the present disclosure; 
         FIG. 15  illustrates an additional alternative embodiment of a securing device including a sliding bracket sitting between a memory module and the circuit board, in accordance with the present disclosure; and 
         FIGS. 16-19  illustrate various exemplary attachments that can secure a bracket device or devices to a PCB, in accordance with the present disclosure; 
         FIG. 16  illustrates a first set of screws fastening a first bracket device to a PCB and a second set of screws fastening a second bracket device to the first bracket device; 
         FIG. 17  illustrates an exemplary adhesive affixing a bracket device to a PCB; 
         FIG. 18  illustrates an exemplary set of rivets affixing a bracket device to a PCB; and 
         FIG. 19  illustrates an exemplary set of vibration weld joints securing a bracket device constructed of a polymer to a PCB. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure resolves the issues of using memory modules such as small outline dual in-line memory modules (SODIMM) in high shock and vibration environments. Devices securing modules to boards are known to include spring clips that permit manual retention. A user pressing a finger against the module or against a spring clip can cause the known securing device to release the memory module. 
     A securing bracket device is disclosed, wherein the device includes a bracket that securely holds the module to a surface and wherein the device is fastened to the surface. Exemplary configurations include fasteners, rivets, adhesive, or thermally activated joints affixing the bracket in place. The disclosed securing bracket device firmly holds the memory module against and electronically engaged to the corresponding memory socket until or unless the bracket is first removed. The disclosed securing device also allows for a lower cost, higher quality, and improved serviceability. 
     SODIMM modules and sockets will be disclosed for use with the disclosed securing device. It will be appreciated that the devices disclosed herein can be used with other types of memory modules or other modularly attachable computer components within a computerized unit, and the disclosure is intended to cover any and all similar connections of components to a computerized unit. 
     SODIMMs are mass produced and used in high volume and hence are less costly. The alternative of buying and soldering down memory chips directly on the main printed circuit board (PCB) is very costly along with other unwanted side effects. Allowing SODIMM sockets to be used will remove a considerable amount of design time from the main board design, speeding up time to market. SODIMM memory modules have the majority of the high-speed memory design requirements already incorporated into the module. The specific timing requirements for the memory modules themselves on the SODIMM are stored on a device that is also present on the module freeing the design engineer from dealing with timing issues on the main PCB. The timing requirements of the memory are simply read from the device on the SODIMM module by the CPU (Central Processing Unit). 
     The use of secured but modularly replaceable SODIMMS as disclosed herein frees the user from having to pick the correct amount of memory at time of order. Such modular installation allows for the ease of future upgrades. Soldered down memory chips cannot be changed where SODIMM modules can be exchanged for higher capacity SODIMM modules. 
     Issues caused by the discontinuation or end-of-life of a particular memory device are greatly reduced. Standard memory chips are frequently discontinued, challenging the designer to find new chips or to redesign the main board to accommodate newer chips, if the memory chips have been soldered directly to the main PCB. By allowing the use of standard SODIMM modules in high shock and vibration environments, the designer simply finds a similar, compatible SODIMM module and plugs it in. 
     Another benefit of the disclosed device is space savings. Space on a PCB is extremely valuable in most applications. SODIMM modules in a stacked configuration as disclosed herein can save board space in high shock and vibration applications that previously required the memory chips to be spread out and soldered to the PCB. 
     An additional benefit of the disclosure relates to cooling of the SODIMM modules(s). The disclosed device along with the use of TIM (Temperature Interface Material) the module is more secure as well as conducting heat away from the memory chips on the modules. Heat spreaders have long been known in the industry to help cool the module but current designs with heat spreaders still use the clips included with the sockets to secure the device. One embodiment of the disclosure provides a method of holding the SODIMM and also provides a heat path for all the memory chips on the modules to be spread and conducted into the copper planes within the PCB. 
     The disclosed securing device solves the issues of using memory modules also referred to as SODIMM modules with the use of standard memory sockets in high shock and vibration applications. The disclosed device includes a module-securing bracket that restricts movement of the memory module in all three axis X, Y, and Z. The disclosed device also provides a means to which the modules can be conduction cooled. Memory modules are designed to meet industry standard specifications like JEDEC MO-268. The disclosed device is designed to comply with those standards by providing a method to secure and cool the modules that typical memory sockets do not provide. 
     Referring now to the drawings, wherein the showings are for the purpose of illustrating certain exemplary embodiments only and not for the purpose of limiting the same,  FIG. 1  illustrates a typical memory module socket that is standard in the industry. Memory socket  20  is illustrated attached to PCB  5 . Memory socket  20  includes spring clips  30   a  and  30   b  integrally attached to the memory socket and including features configured to securely hold locator cut-outs  14   a  and  14   b  on either side of a matching memory module. Memory module  10  is illustrated, with connector region  12  plugged into connector slot  22  of socket  20 . Socket  20  firmly grips connector region  12  of module  10  when the module is fully engaged and the module is held in line with spring clips  30   a  and  30   b  and snuggly pushed against socket  20 . However, spring clips  30   a  and  30   b , which snuggly pushes module  10  against socket  20  when the spring clip features are engaged to locator cut-outs  14   a  and  14   b , are specifically configured to easily release module  10  when a user depresses one of the spring clips. 
     Such an easily releasable configuration can be acceptable in a laptop or other commercial/consumer application. Most people guard against dropping a laptop, and if they do, any resulting loss of connection between a SODIMM module and its socket is an easily recoverable condition. Such a risk is widely accepted in the consumer world. However, in military and industrial applications, loss of memory chip function can be catastrophic. For example, a tank in combat includes many electronic systems and modules, for example, for maneuvering the vehicle, for controlling the turret, for communicating, and for identifying and tracking targets. If the tank is struck by an enemy shell or if the tank collides with a barrier, the resulting mechanical shock to the tank could cause a standard SODIMM socket to release its memory module, thereby causing an unacceptable system crash. Similarly, a crane lifting multi-ton logs on a worksite depends upon computerized systems to maneuver, to control a lifting arm, and to communicate with workers around the crane. If vibration causes a memory module to be released from the associated SODIMM socket, the user could lose control of the crane and the logs being lifted. 
       FIG. 2  illustrates an exemplary securing device installed to a memory socket and memory module, the securing device preventing the memory module from accidentally disengaging from the memory socket. Memory socket  20  is illustrated attached to PCB  5 . Memory socket  20  includes spring clips  30   a  and  30   b  integrally attached to the memory socket and including features configured to securely hold locator cut-outs on either side memory module  10 . Securing device  100  is illustrated in location to be lowered upon module  10  and securingly hold module  10  against socket  20 . Device  100  includes holes  106  and  108  which line up with holes  102  and  104 , respectively, on PCB  5 , such that fasteners  110  and  112  can be used to securely affix device  100  to PCB  5 . Device  100  includes features to prevent module  10  from moving away from socket  20 . Device  100  can include features to secure spring clips  30   a  and  30   b  such that the clips cannot be activated to release the module  10  when the device is affixed to the PCB  5 . 
       FIG. 3  illustrates in cross-section the components of  FIG. 2 . Device  100  is illustrated attached to PCB  5  and holding module  10  against socket  20 . Device  100  includes a portion  120  that covers a top side of module  10  and prevents movement of module  10  away from PCB  5 . Device  100  includes portion  124  which acts as a spacer between module  10  and PCB  5 , preventing the module from moving closer to the PCB. Device  10  includes portion  122  which prevents module  10  from moving away from socket  20 . Socket  20  prevents module  10  from moving to one side or the other of socket  20  (in the direction of the viewer or away from the direction of the viewer in  FIG. 3 ) so long as module  10  is engaged to socket  20 , but device  100  can include further features to prevent side-wards movement of module  10 . 
       FIG. 4  illustrates an alternative embodiment of a securing device including tabs for securing to locator cut-outs on either side of a memory module. If a socket is utilized that does not include spring clips, features can be added to a securing device to grip a memory module by its locator cut-outs. Securing device  200  is illustrated including cavity  210  for holding a memory module. Walls  216 ,  218 , and  220  are configured to a particular size of memory module and abut securely to the sides of the module. Features  212  and  214  are configured to fit into locator cut-outs for the module. Holes  202 ,  204 ,  206 , and  208  are provided to affix device  200  to a PCB. 
       FIG. 5  illustrates an additional alternative embodiment of a securing device including heat dissipation fins. Securing device  300  is illustrated attached to PCB  5  and securely holding module  10  to socket  20 . Holes  302  and  304  are illustrated to securely affix device  300  to PCB  5 . Memory chips and the associated module generate heat, and methods to transfer heat away from a memory module can be beneficial. Device  300  can be constructed of any material known for use in computers. Materials can be used such as copper or aluminum that are conductive to heat and that will transfer heat away from the module. Fins  310  are illustrated increasing a surface area of device  300  to improve heat conduction from device  300  into surrounding air. 
       FIG. 6  illustrates an additional alternative embodiment of a securing device in combination with layers of TIM material. Socket  420  is illustrated holding an alternative memory module  408 . Sheets  430  and  432  of TIM material are illustrated provided between module  408  and securing device  400  and between module  408  and substrate surface  405 , respectively. The TIM material is known in the art for improving heat transfer between two surfaces. Further, the TIM material can be used to take up space between layers such as between the module and PCB. By taking up this space, the module is less likely to move relative to the memory socket and the PCB and instead will tend to move in unison with the PCB. Device  400  includes features for holding locator cut-outs  414   a  and  414   b  of module  408 , and device  400  includes holes  420 ,  422 ,  424 , and  426  to receive fasteners  440  which are installed from a bottom side of substrate  405 . 
       FIG. 7  illustrates an additional alternative embodiment of a securing device including a pair of side brackets. Socket  20  is illustrated attached to PCB  5 . Brackets  400  and  410  are shown in approximate locations to affix a memory module to socket  20 , each bracket affixing to a short side of the memory module, with the brackets  400  and  410  flipped over to reveal details of the brackets. Features  402  and  412  are provided to hold locator cut-outs on a module. Holes  404 ,  406 ,  414 , and  416  are provided to attach the brackets to PCB  5 . When installed, both brackets  400  and  410  would be flipped over with features  402  and  412  pointing down toward the PCB and pointing inward toward each other. As disclosed in relation to  FIG. 6 , TIM material can be used between the PCB and the module to dissipate heat and take up the space between the PCB and the module. 
       FIG. 8  illustrates an additional alternate embodiment of a securing device including a slotted frame bracket and leaving spring clips off of the memory socket. Socket  520  without any spring clips installed thereto and memory module  510  are illustrated. A securing device embodied as slotted frame bracket  500  is illustrated snuggly holding module  510  against socket  20 . Bracket  500  includes a flat wall surface  506  configured to match an end  512  of module  510 . SODIMM modules have areas that can be contacted by a bracket and other areas that cannot due to electronic features on the module. According to one embodiment of SODIMM modules, the end of module  510  adjacent to surface  506  cannot be contacted on top or bottom surfaces by the bracket  500 . By presenting surface  506  against the narrow end surface of module  510 , the bracket can retain the module  510  against the socket  20  without violating the rules against contacting the module on the top or bottom of the module. Bracket  500  includes holes  502  and  504  for holding the bracket to the PCB. While holes and fasteners are illustrated as easy ways to affix a securing device to a PCB or other substrate, it will be appreciated that any mechanical system for securing the device can be utilized. 
       FIG. 9  illustrates in cross-section the components of  FIG. 8 . Device  500  and socket  520  are illustrated affixed to PCB  5 . Device  500  includes flat wall surface  506  abutting end  512  of module  510 . Device  500  and socket  520  securely hold module  510  from all sides and prevent any movement of the module relative to PCB  5 . By locating a flat wall to an end of the memory module distal to the connection to the socket, the bracket device can prevent the memory module from accidentally disengaging from the socket. 
       FIG. 10  illustrates the securing device of  FIG. 8  with a different memory socket maintaining spring clips. Socket  20  with spring clips  30   a  and  30   b  installed thereto and memory module  510  are illustrated. Slotted frame bracket  500  is illustrated snuggly holding module  510  against socket  20 . Bracket  500  includes holes  502  and  504  for holding the bracket to the PCB. A securing device such as bracket  500  can be configured for use with sockets with or without spring clips installed to the socket. 
       FIG. 11  illustrates an alternative memory socket configuration including a first memory module and memory socket and a second memory module and memory socket. Stacked socket configurations are known for providing augmented memory capacity to a computerized device while limiting space used on the PCB. Socket  630   a  is illustrated to engage a first memory module  610   a , and a second socket engages illustrated second memory module  610   b . Securing devices  600  and  620  are illustrated for holding modules  610   a  and  610   b , respectively, against their respective sockets. Device  600  includes features for securely holding locator cut-outs  614   a  and  614   b  of module  610   a . Device  620  similarly includes features for securely holding module  610   b . Device  620  includes holes  622   a ,  624   a ,  626   a , and  628   a  such that fasteners can hold the device to the PCB. Device  600  includes holes  602 ,  604 ,  606 , and  608  such that fasteners can hold the device to the PCB. Device  620  includes holes  622   b ,  624   b ,  626   b , and  628   b  such that the fasteners holding down device  600  can pass through device  620 . In another embodiment, screws on an opposite side of the PCB could pass through open holes on the PCB and engage to threaded holes on device  620  to hold device  620  to the PCB, and other screws could pass through open holes on device  600  and engage to threaded holes on device  620  to hold device  600  to device  620 . A number of methods to affix bracket devices as disclosed herein to a PCB, a substrate, or to another device are envisioned, and the disclosure is not intended to be limited to the particular examples provided herein. 
       FIG. 12  illustrates the memory socket configuration of  FIG. 11  in assembly view. Module  610   a  is connected to socket  620   a , and module  610   b  is connected to socket  620   b . Device  620  is positioned to securely hold module  610   b  to a PCB or substrate. Device  600  is positioned to securely hold module  610   a  to a PCT or substrate. Layers  630  of TIM material are positioned above and below both modules to facilitate heat transfer away from the modules. 
       FIG. 13  illustrates an alternative memory socket configuration including an alternative memory module. Memory modules can include different configurations than SODIMM modules, such as DIMM modules commonly used in desktop computers. DIMM sockets have flip up levers that secure DIMM modules by swinging upward as the module is pushed into the socket. However, these manually activated tabs can similarly dislodge when subjected to shock or heavy vibration. DIMM module  710  is illustrated inserted into DIMM socket  720 , with two flip up levers of the socket engaging sides of the DIMM module. Bracket device  700  is illustrated, including surfaces  701 ,  703 , and  705  which engage to module  710  and/or the flip up levers of socket  720  according to similar embodiments of the disclosure to prevent the memory module from disengaging from the socket without the bracket first being removed. Screws  712  are illustrated for attachment of the bracket device  700  to PCB  705  though holes  720  and  704  to threaded screw holes  708  and  706 , respectively. 
       FIG. 14  illustrates an additional alternative embodiment of a securing device including a pair of brackets, each bracket securing one spring clip. Memory module  10  is illustrated engaged to socket  20  which is attached to PCB  5 . A securing device embodied as brackets  800  and  802  is illustrated, wherein the brackets each secure and reinforce one of the spring clips  30   a  and  30   b . Brackets  800  and  802  can include cavities  804  and  806 , respectively, to locate to features of the socket and spring clips. By securing and immobilizing the spring clips, brackets  800  and  802  secure module  10  and prevent module  10  from being dislodged from socket  20  by shock or vibration. 
       FIG. 15  illustrates an additional alternative embodiment of a securing device including a sliding bracket sitting between a memory module and the circuit board. Socket  20  including slot  22  is illustrated. Securing device  900  is illustrated slidingly attached to PCB  5 . Device  900  includes slots  910  and  912  with fasteners  914  and  916 , respectively, selectively securing a position of device  900  in relation to the PCB board by either permitting or restricting movement of the device by the fasteners sliding through the slots. When a module is placed in slot  22  of socket  20 , device  900  can be slid toward socket  20 , with wall  918  pressing against the module and with tabs  920  and  922  capturing the module and preventing the module from moving up away from the PCB  5 . Flat surface  917  supports the module and prevents the module from moving toward the PCB. Depending upon a height of device  900 , a heightened socket or a spacer  905  may have to be used to compensate socket position for any added distance that the memory module is moved away from PCB  5  by device  900  being located under the module. Once the module is in place, fasteners  914  and  916  can be tightened to securely fasten the module in place. In one embodiment, slots  910  and  912  can each have a depression configured to the head of fasteners  914  and  916 , such that the bracket can be locked into place with the memory module secured against the socket. 
     As described in relation to  FIG. 9 , a memory module can include requirements that nothing contact certain areas of the module. Tabs  920  and  922  can be moved or configured upon the side of device  900  close to slots  910  and  912  for such modules. In future iterations of modules which may have requirements that nothing touch along the sides of the module, tabs such as tabs  920  and  922  can be utilized. The brackets and any affixing features disclosed herein are exemplary and can be adjusted to fit and affix to later iterations of memory modules not yet in service. 
       FIGS. 16-19  illustrate various exemplary attachments that can secure a bracket device or devices to a PCB.  FIG. 16  illustrates a first set of screws fastening a first bracket device to a PCB and a second set of screws fastening a second bracket device to the first bracket device. A first bracket device  1010  and a second bracket device  1012  are illustrated aligned with matching open screw holes on PCB  1005 . Screws  1009  can be pushed through the open screw holes on the PCB and threaded into screw holes on device  1012 . By tightening screws  1009 , bracket  1012  is affixed to PCB  1005 . Screws  1008  can be pushed through open screw holes on device  1010  and threaded into screw holes on device  1012 . By tightening screws  1008 , bracket  1010  is affixed to bracket  1012 . By separately attaching each bracket, one memory module can be serviced while the other remains independently affixed to the PCB. In another embodiment, a single longer set of screws could go through both a first device and a second device and attach to an adjacent PCB. 
       FIG. 17  illustrates an exemplary adhesive affixing a bracket device to a PCB. Bracket device  1110  is illustrated adjacent to PCB  1105 . An exemplary epoxy-resin adhesive  1108  is illustrated joining device  1110  to PCB  1105 . Any known adhesive that can be used proximately to a circuit board can be used to adhere the device to the PCB. An electrically inert adhesive can be used to avoid any contamination or shorting on the module. 
       FIG. 18  illustrates an exemplary set of rivets affixing a bracket device to a PCB. Bracket device  1210  is illustrated attached to PCB  1205  with rivets  1208 . While rivets are not as easily serviced as a set of screws that can be removed with a screwdriver, rivets still permit a user to use and benefit from a modular SODIMM module instead of soldering chips directly to the board. Additionally, while rivets may be difficult to service in the field, a technician could remove the PCB and remotely pop the rivets before replacing the rivets and reinstalling the PCB to the same or a similar vehicle or application. 
       FIG. 19  illustrates an exemplary set of vibration weld joints securing a bracket device constructed of a polymer to a PCB. PCB  1305  is illustrated including a set of plastic plates  1306  affixed to the PCB. Polymer bracket device  1310  is illustrated including connecting areas  1308  located proximately to plates  1306 . By joining methods known in the art such as vibration or sonic welding, portions of areas  1308  and plates  1306  melt and are sealed to each other, thereby affixing device  1310  to PCB  1305 . 
     The disclosed device is illustrated securing a SODIMM module to a circuit board. It will be appreciated that the disclosed device could be modified for any number of module or module configurations wherein the module or module is subject to being dislodged from a circuit board by shock, vibration, or other environmental factors. In one embodiment, the disclosed device can include a structure to seal around the module and prevent dust or other contaminants from infiltrating between the module and the proximate socket. 
     The bracket disclosed herein can be constructed of any known material. In one embodiment, the bracket can be constructed of a material encouraging heat conduction away from the module being fastened. Aluminum, copper, and related alloys are envisioned as being materials used for the bracket. In another embodiment, steel can be used. 
     In one embodiment, where heat removal is of great concern, the disclosure can be constructed from aluminum with an internal fin cavity, allowing the passage of a cooling liquid to enable the disclosure to both restrain the SODIMM module and provide liquid cooling. In another embodiment, one side of the disclosure can be mated to a SODIMM memory module and the other side to a thermoelectric cooling element that in turn is matched to a larger heat exchanger. 
     In other embodiments wherein heat conduction is not as critical as other issues, such as cost or weight, one can use plastics or other polymers to construct the bracket. Such a polymer configuration can include holes or vents in the bracket to permit convection of air past the contained module to mitigate any thermal insulation caused by use of the polymer bracket. The examples of materials used to construct the bracket is intended as non-limiting examples of how the device may be constructed. 
     In one embodiment, the disclosed device comprises a bracket including a feature for securely holding the module, and wherein the device is affixed to the circuit board. In one embodiment, the disclosed device is configured to securely hold the module against a socket configured to electronically connect with the module. The feature can include a module shaped cavity in the bracket. The feature can include a first cavity on a first bracket shaped to a small portion of the module and a second cavity on a second bracket shaped to another small portion of the module, wherein the two brackets together opposingly pinch or otherwise grip the module to keep it in place. 
     The disclosure has described certain preferred embodiments and modifications of those embodiments. Further modifications and alterations may occur to others upon reading and understanding the specification. Therefore, it is intended that the disclosure not be limited to the particular embodiment(s) disclosed as the best mode contemplated for carrying out this disclosure, but that the disclosure will include all embodiments falling within the scope of the appended claims.