Abstract:
A fan assembly that can be easily inserted into a mating slot comprises: a housing surrounding and supporting a fan, a least one grill positioned so as to restrict access to the fan, a grip surface on the housing, a latch on the housing and configured to engage the mating slot; and, and an electrical connector mounted in the housing. The grip surface is formed on a separate piece from the housing and is affixed to the housing by an integrally formed fastening device and the assembly comprising the housing, grill, grip surface, latch and connector can be assembled by hand without the use of separate fasteners.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
         [0001]    Not applicable.  
         STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
         [0002]    Not applicable.  
         BACKGROUND OF THE INVENTION  
         [0003]    1. Field of the Invention  
           [0004]    The present invention relates generally to a hot plug fan for use in a computer. More particularly, the present invention relates to a fan housing that includes a floating connector and can be rapidly assembled without the use of tools. Still more particularly, the present invention relates to a fan assembly that includes snap-together parts that form a housing that can releasably engage a slot in a computer housing.  
           [0005]    2. Background of the Invention  
           [0006]    Fans or other air moving devices for a file server or other computer are often mounted in a vertical fan support housing. For operational convenience and flexibility, each fan is typically “hot plug” connected within the support housing. As used herein the term “hot plug” or “hot-pluggable” refers to any type of electrical connection that permits the equipment in question to be removed and re-installed or replaced without disturbing the operation of other components.  
           [0007]    In conventional practice, each fan is mounted inside a fan cage, and includes a connector tethered on a cable. The connector is insertable into a back plane hot plug socket within the fan support housing. The fan cage must be assembled around the fan and connector and cable using several fasteners and the fan cage itself must then be inserted with precision, so that the tethered connector is properly aligned and connected. Some or all of the following problems, limitations and disadvantages are commonly associated with conventional hot plug fan assemblies of this general type:  
           [0008]    1. The assembly steps are time consuming and therefore costly and it is desirable to provide a fan assembly that can perform at least as well as conventional fan assemblies without requiring as much assembly time.  
           [0009]    2. In addition to requiring several assembly steps, the conventional fan cage requires a significant volume of space, which is then unavailable for use as part of the fan operating volume. As the cooling capability of the fan is a function of its size, it is desirable to reduce the amount of space required by the fan cage.  
           [0010]    3. Furthermore, the tethered connector that is used to make the hot plug must be manipulated into position in order to make the electrical connection. This make it necessary to achieve relatively tight tolerances in the manufacturing of the components so as to avoid mis-installing or damaging the connector. Tight tolerances, in turn, increase manufacturing costs. Hence, it is desired to provide a hot plug fan that can engage the corresponding hot plug socket without requiring tight tolerances.  
           [0011]    4. The use of a separate assembly for holding the tethered connector and fan tends to increase both the complexity and cost associated with removably supporting each fan, and typically presents wire ends, which the installer must carefully handle to avoid cable damage when installing and removing the fan from the cage. Hence, it is desired to provide a caged fan that does not require a separate connector assembly in its cage.  
           [0012]    5. On some caged fans, a considerable amount of manual pulling force is required to disconnect the board from its associated hot plug socket within the cage. Other conventional fans must be screwed or pinned to the support socket, thereby increasing the overall complexity and fabrication cost of the support system. Hence, it is desired to provide a fan that can be removed and replaced under hot plug conditions without undue force or the use of tools.  
           [0013]    It can be seen from the foregoing that it would be desirable to provide a hot plug fan assembly with a variety of operational, assembly, and safety improvements. It is accordingly an object of the present invention to provide hot plug-connected fan assembly incorporating such improvements.  
         BRIEF SUMMARY OF THE INVENTION  
         [0014]    The present invention provides a fan assembly having many desirable features. Specifically, the present invention provides a fan assembly that can perform at least as well as conventional fan assemblies and requires much less assembly time. The present fan assembly also reduces the amount of space required by the fan cage, thereby allowing a larger fan to be fit into a given slot size. In a preferred embodiment, the present fan assembly provides a hot plug fan that includes a floating connector that can engage the corresponding hot plug socket without requiring tight tolerances. The present fan assembly does not require a circuit board in its cage, and can be removed and replaced under hot plug conditions without undue force or the use of tools. For all of these reasons, the present fan assembly provides a variety of operational, assembly, and safety improvements.  
           [0015]    According to one preferred embodiment, the present invention comprises a fan housed in a fan housing, and a fan grill, grip plate, and latch plate, all of which can be assembled to form the fan assembly in a few seconds without the use of tools.  
           [0016]    More particularly, one embodiment comprises a fan assembly that can be easily inserted into a mating slot. The assembly includes: a housing surrounding and supporting a fan, at least one grill positioned so as to restrict access to the fan blades, a grip surface on the housing, a latch on the housing configured to engage the mating slot, and a electrical connector mounted in the housing. The grip surface is formed on a separate piece from the housing and is affixed to the housing by an integrally formed fastening device and the assembly comprising the housing, grill, grip surface, latch and connector can be assembled by hand without the use of separate fasteners.  
           [0017]    In further embodiments, the latch is included on a latch piece that is separate from the housing, and may be affixed to the housing by an integrally formed fastening device, the connector is included on a connector piece that is separate from the housing and may be affixed to the housing by an integrally formed fastening device, and/or the grill is included on a grill piece that is separate from the housing and may be affixed to the housing by an integrally formed fastening device.  
           [0018]    In still further embodiments, the fan assembly includes a grip piece and the grill piece is maintained in alignment with the housing by the grip piece. Alternatively, or in addition, the fan assembly includes a latch piece, which may maintain the grip piece in engagement with the housing.  
           [0019]    It is preferred that the grill, the latch, and the grip are assembled sequentially, with each piece engaging the housing and maintaining the previously assembled pieces in engagement with the housing.  
           [0020]    The present fan assembly can also include an electrical connector that includes at least one pin. The electrical connector is mounted on the housing such that the connector can move in directions normal to the pin but is substantially restrained from moving in directions parallel to the pin. In a preferred embodiment, the electrical connector is held in place on the housing by a connector clip that snaps into the housing. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]    For a more detailed discussion of the preferred embodiments of the invention, reference will be made to the accompanying Figures, wherein:  
         [0022]    [0022]FIG. 1 is an exploded view of one embodiment of the present fan assembly;  
         [0023]    [0023]FIG. 2 is a perspective view of the assembled fan housing of FIG. 1;  
         [0024]    [0024]FIGS. 3 and 4 are bottom and perspective views, respectively, of the grill  50  of FIG. 1;  
         [0025]    [0025]FIGS. 5 and 6 are inner and side views, respectively, of the grip plate of FIG. 1;  
         [0026]    [0026]FIGS. 7 and 8 are outer and side views, respectively, of the latch plate of FIG. 1; and  
         [0027]    [0027]FIG. 9 is an exploded view of the connector of FIG. 1. 
     
    
     NOTATION AND NOMENCLATURE  
       [0028]    Certain terms are used throughout the following description and claims to refer to particular system components. As one skilled in the art will appreciate, computer companies may refer to a component by different names. This document does not intend to distinguish between components that differ in name but not function. In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . ”. Also, the term “couple” or “couples” is intended to mean either an indirect or direct electrical connection. Thus, if a first device couples to a second device, that connection may be through a direct electrical connection, or through an indirect electrical connection via other devices and connections.  
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0029]    Referring initially to FIG. 1, a preferred embodiment of the present fan assembly includes a fan  10  in a fan housing  20 , a grill  50 , grip plate  100 , and latch plate  150 .  
         [0030]    Fan  10  is a conventional motor-driven fan such as are commonly used to cool computer components. According to a preferred embodiment, fan  10  is factory-mounted within fan housing  20  so as to be rotatable within the housing. Fan housing  20  is typically substantially square shaped, so as to slide into a corresponding slot in the computer. It is preferred that the diameter of the fan be only slightly smaller than the width of fan housing  20 , so as to maximize the size of fan  10  within the available space.  
         [0031]    According to a preferred embodiment, housing  20  includes a substantially flat front plate  24  and a substantially flat rear plate  26 , with a cylindrical fan shroud  28  extending between them. Housing  20  also includes at least one brace  30  extending between front and rear plates  24 ,  26 . In a preferred embodiment, a plurality of braces  30  are provided, with each brace being substantially planar and extending between front and rear plates  24 ,  26  in the comers defined between the perimeter of fan shroud  28  and the perimeter of front and rear plates  24 ,  26 . Braces  30  serve a variety of purposes, as discussed below, including providing mechanical strength and rigidity to housing  20 . Front plate  24  preferably includes one hole  33 ,  35 ,  37 ,  39  in each corner and a slot  34  adjacent to hole  33 . Likewise, rear plate  26  preferably includes holes  43 ,  45 ,  47 , and hole  49  (not shown) in each corner and a slot  44  (not shown) adjacent to hole  43 .  
         [0032]    It is further preferred that fan housing  20  include at least one fan guard or grill  22  that is formed integrally as part of fan housing  20 . It is more preferred that fan housing  20  include two grills, with one on each side of fan  10 , but it is believed that it will be more economical to manufacture fan housing  20  with an integral single grill.  
         [0033]    In view of this fact, a separate, a second, separate grill  50  is provided, as shown in FIGS.  1 - 2 . Grill  50  can be added after assembly of fan  10  in housing  20  is complete. Grill  50  includes a circular guard portion  52 , which prevents inadvertent contact with the fan blades, and an integrally formed substantially square plate  54 , which defined four comers around guard  52 . Grill  50  includes holes  55 ,  57 , and  59  (FIG. 4) in its comers, whose positions correspond to the positions of holes  35 ,  37 , and  39  on front plate  24 .  
         [0034]    Referring particularly to FIGS. 3 and 4, one corner of plate  54  is preferably provided with a split retaining pin  53  on its inside face. Split retaining pin  53  snaps into and releasably engages hole  33  in one corner of fan housing  20  and provides a means for maintaining grill  50  in a desired position on the face of fan housing  20  without requiring the use of tools to attach grill  50  to fan housing  20 . It will be understood that other snap-type mechanisms, including tabs or a snap ring, and other non-snap devices, such as adhesive, can be used to provide an easily engaged, releasable connection between grill  50  and fan housing  20 .  
         [0035]    If a split retaining pin  53  is used to hold grill  50  in place, it is preferred to provide only a single pin  53 , rather than, for example, a pin at each comer. Previous assemblies used up to four or five deformable plastic rivets to secure grill  50  to housing  20 . Using a single pin allows the connection between grill  50  and housing  20  to be made quickly, as only one pin needs to be aligned. Even though grill  50  can rotate about pin  53  with respect to fan housing  20 , in a preferred embodiment grill  50  is subsequently held in its desired position by other components, as discussed in detail below. In addition, it is preferred to provide one edge of plate  54  with at least one, and preferably two, fingers  58 , which snap over the edge of front plate  24  when split retaining pin  53  engages plate  24 . Fingers  58  help to align grill  50  with front plate  24 .  
         [0036]    Once fan housing  20  is equipped with two grills, grip plate  100  is installed. As shown in FIGS. 1, 5 and  6 , grip plate  100  preferably includes a substantially flat panel  102 , with a finger hole  103  near one end and a plurality of perpendicularly extending latching tabs  106 ,  108 ,  110 ,  112 . Tabs  106 ,  108 ,  110 ,  112  are preferably perpendicular to the inner surface of panel  102  and parallel to the long axis of panel  102 . Latching tabs  106  and  108  are adjacent to finger hole  103  and are approximately as far apart as the distance between the outer surface of grill  50  and the outer surface of rear plate  26 . Latching tabs  110  and  112  are at the opposite end of panel  102  and are also approximately as far apart as the distance between the outer surface of grill  50  and the outer surface of rear plate  26 . Tabs  110  and  112  each include a hole  137 ,  147  therethrough. Tabs  106  and  108  each include a boss  135 ,  145  extending from their inner surfaces toward finger hole  103 . Grip plate  100  also preferably includes a stop  148  extending perpendicularly to its inner surface and perpendicularly to its long axis.  
         [0037]    When grip plate  100  is added to the fan/grill assembly, boss  135  engages both holes  55  and  35  on grill  50  and front plate  24 , respectively. Boss  145  engages hole  45  on rear plate  26 . Tabs  110  and  112  bracket the fan/grill assembly. The engagement of bosses  135  and  145  maintains grip plate  100  in its desired position on housing  20 . The engagement of boss  135  also prevents grill  50  from rotating with respect to housing  20 . Because in a preferred embodiment grill plate  54  overlap the edge of front plate  24 , hole  55  is farther from the overlapping edge of plate  54  than it is from the adjacent edge. Grip panel  102  extends over this edge and thereby prevented from rotating about the axis defined by bosses  135 ,  145 . It will be understood that rotation of grip plate  100  with respect to the fan/grill assembly could be prevented in a variety of ways, such as by using square-sectioned bosses, or by not rounding the comers of either plate  54  or  24 , and the preferred construction is not intended to be limiting.  
         [0038]    Referring now to FIGS. 1, 7, and  8 , latch plate  150  includes a substantially flat panel  152  with tabs  156 ,  158 ,  160 , and  162  extending perpendicularly from its long edges. Tab  156  includes an outward dogleg  163  and a boss  157  extending perpendicularly from its inner surface. Tab  158  is substantially straight and includes a boss  159  extending perpendicularly from its inner surface. Tab  160  includes an outward dogleg  164  and a boss  167  extending perpendicularly from its inner surface. Tab  162  is substantially straight and includes a boss  169  extending perpendicularly from its inner surface. While the distance between each pair of tabs  156 ,  160  and  158 ,  162  substantially equal to the distance between the outer surface of grill  50  and the outer surface of rear plate  26 , dog legs  158  and  164  allow the ends of tabs  156 ,  160  to encompass all of the thicknesses of the assembled components.  
         [0039]    Latch plate  150  also includes a central spring-loaded latch member  170 . Latch member  170  is preferably formed by providing two parallel slots  172 ,  174  in from one short edge of panel  152 , and bending the resulting tongue  178  slightly outward, so that it does not lie in the plane of panel  152 . Tongue  178  preferably includes a outwardly extending boss  180 .  
         [0040]    When latch plate  150  is added to the fan/grill/grip assembly, boss  157  engages all three holes  135 ,  57  and  37 , boss  159  engages both holes  59  and  39 , boss  167  engages both holes  147  and  47 , and boss  169  engages hole  49 . Because the various bosses engage differing thicknesses of material, it is preferred that they have correspondingly different lengths. For this reason, it is further preferred that they engage their respective holes in the order recited above.  
         [0041]    Once all four bosses on latch plate have engaged their respective holes, the four components of the present fan assembly, namely fan housing  20 , grill  50 , grip plate  100  and latch plate  150  are substantially rigidly held in place. This configuration allows for adaptability of the parts and provides an assembly that is much faster and simpler to assemble than previously known assemblies. Because of the slight deformations that must occur as the components are snapped into place, it is preferred to construct the components from a substantially rigid but slightly flexible material, such as are known in the art.  
         [0042]    Referring now to FIGS. 9 and 10, a preferred connector clip  200  for use with the present assembly includes a substantially flat panel  202  with a substantially rectangular central opening  204  therethrough. Panel  202  is sized such that its width w is less than the length of one side of one corner of front plate  24  where it extends beyond fan shroud  28  and its length I is slightly less than the distance between the inner surface of front plate  24  and the inner surface of rear plate  26 . Each end of panel  202  includes a retaining finger  210  extending perpendicularly therefrom. Each retaining finger preferably includes an outwardly extending lip  212  with a tapered back surface  214 . The distance between the outer edges of lips  212  is preferably greater than the distance between front plate  24  and rear plate  26 .  
         [0043]    Connector clip  200  engages and supports an electrical connector  220  (FIG. 11), which provides multiple electrical connections between wires  222  and a corresponding plurality of sockets using a plurality of pins  223  (shown in phantom). The mating side of connector  220  preferably has a chamfered mouth, so as to facilitate alignment of the electrical connectors. Wires  222  provide power and control signals to fan  10 , as is known in the art. The method of engagement between clip  200  and connector  220  can be any suitable devices, but is preferably one that allows some movement of connector  220  with respect to clip  200 . For example one such engagement is made by providing an opening  204  in panel  202  that is at somewhat larger than the outer dimensions of connector  220  and providing snap-in type connections  224  between connector  220  and clip  200 , so that once connector  220  is snapped into clip  200  it has a small range of movement in two lateral directions, but is prevented from moving out of the plane of clip  200 . Alternative ways to achieve this type of connection include, but are not limited to elastomeric connections, or other types of retaining mechanisms that allow some movement of connector  200 , such as a retaining bar or lid.  
         [0044]    With connector  220  snapped into or otherwise engaging connector clip  200 , clip  200  is preferably mounted on the present fan assembly by inserting panel  202  between front plate  24  and rear plate  26  such that one retaining finger  210  engages each of slots  34  and  44 . More specifically, tapered back surfaces  214  engage the edges of plates  24  and  26  and cause fingers  210  to flex inward until the edges of lips  212  fit between front plate  24  and rear plate  26 . Connector clip  200  is inserted until lips  212  snap into slots  34  and  44  as fingers  210  return to their un-flexed state.  
         [0045]    The width of fingers  210  is preferably slightly less than the width of slots  34  and  44 . This feature, along with the fact that the length of panel  202  is less than the distance between front plate  24  and rear plate  26  allows connector clip  200  to move in both the x and y directions, but not in the z direction. As drawn, the z direction is parallel to the axes of the pins in the connectors. This arrangement is desirable for the reasons discussed below.  
         [0046]    With the fan assembly fully assembled, including grill  50 , latch plate  150 , grip plate  100 , connector  220  and connector clip  200 , it is ready to be installed in a computer. The fan assembly is preferably slid into a slot (not shown) in a computer such that the face of housing  20  that is opposite grip plate  100  is at the rear or bottom of the slot. In this position, boss  180  on latch tongue  178  engages a corresponding latching mechanism on one side of the slot and grip plate  100  faces outward. Because connector  220  has a chamfered opening, it will tend to be guided into the correct alignment as the fan assembly is lowered into the slot and connector  220  begins to engage its corresponding connector. This in turn is possible because of the play or movement that is designed into the structure supporting connector  220 . The fan assembly is slid into the slot until the connector  220  fully engages a corresponding connector, preferably on a circuit board, and latch tongue  178  snaps into engagement with the slot.  
         [0047]    Latch tongue  178  serves to keep the fan assembly from falling out of or being inadvertently removed from the slot. When it is desired to remove the present fan assembly from the slot, removal may be accomplished by inserting one thumb or finger into finger hole  103  and squeezing the free end of tongue  178  toward finger hole  103 . Because finger hole  103  is generally aligned with tongue  178  across the width of the assembly, this can comfortably be accomplished using one hand. This disengages tongue  178  from the slot and the fan assembly can be lifted or slid out of the slot. Because connector  220  is prevented from moving in the z direction with respect to the housing, it will be disconnected from the circuit board as the fan assembly is withdrawn from the slot.  
         [0048]    The present fan assembly is hot-pluggable, which means that it can be removed from the computer in which it operates with out disrupting operation of that computer. Because the present fan assembly can be connected to the computer both electrically and mechanically without the use of tools, it provides significant advances over the previous state of the art. Both the electrical connection and the mechanical connection can be hot-plugged without any need to adjust alignment or tighten fasteners.  
         [0049]    While the fan support apparatus representatively described above provides hot plug connections for the fans, it will readily be appreciated by those skilled in this art that it could also be employed using non-hot plug socket connections for the fans if desired.