Abstract:
A fastening between a fan shroud and a heat exchanger, the fastening including a plurality of cooperating fastening devices about the outer edge of the shroud and heat exchanger. At least one of the cooperating fastening devices comprises a locking hook on one edge of the shroud, a mount on an edge of the heat exchanger corresponding to the shroud one edge, a stop on the corresponding heat exchanger edge spaced from the mount slot in a direction opposite a first direction, and an elastically flexible extension on the locking hook including a locking tab. The mount defines a slot adapted to receive the locking hook from the first direction. The extension is elastically biased toward an interfering position between the locking tab and the stop when the locking hook is received in the mount slot, and is manually engageable to flex the extension to a releasing position in which the locking tab does not interfere with the stop.

Description:
CROSS REFERENCE TO RELATED APPLICATION(S)  
         [0001]    Not applicable.  
         STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
         [0002]    Not applicable.  
         REFERENCE TO A MICROFICHE APPENDIX  
         [0003]    Not applicable.  
         TECHNICAL FIELD  
         [0004]    The present invention is directed toward fan assisted heat exchangers, and particularly toward fastening structures for mounting fan shrouds to heat exchangers.  
         BACKGROUND OF THE INVENTION AND TECHNICAL PROBLEMS POSED BY THE PRIOR ART  
         [0005]    Heat exchangers such as vehicle radiators having tubes extending between headers/collecting tanks and plate or serpentine fins are well known. In many applications, such heat exchangers are fan assisted whereby a fan may force air over heat exchange surfaces (e.g., the tube walls and fins) to facilitate heat transfer between the air and coolant or other fluid in the tubes.  
           [0006]    In many such applications, a fan shroud is provided to assist in guiding the fan air over the heat exchange surfaces. Secure and reliable fastening or mounting of the fan shroud relative to the heat exchanger is, of course, important, as is the ability to assemble and, perhaps years later, disassemble such a fastening.  
           [0007]    For example, one known radiator of the type just described is apparent from DE 42 44 037 C2, in which fastening devices on the edge of the fan shroud cooperate with fastening devices on the collecting tanks of the heat exchanger. Although assembly of the fan shroud in the known radiator is also possible when the radiator is also incorporated in a vehicle, disassembly of the fan shroud is difficult, since a tool must be used to loosen the elastic locking hooks molded onto the two collecting tanks to the heat exchanger in order to be able to free them from their locked position. Moreover, it appears that, with a radiator having standard dimensions, it would be difficult for a single assembly person to loosen both locking hooks simultaneously, such loosening being necessary to disassemble the fan shroud. In addition, the arms which run from the frame to the edge of the fan shroud occupy the housing in the vehicle (where space is very limited anyway). Still further, the arms pose a certain risk of injury to the assembly person, especially if they are not carefully deburred.  
           [0008]    A U-shaped housing is also proposed in DE 100 61 561 A1 or in WO 99/47875. One or more heat exchangers are positioned in the housing, and fastening devices which cooperate with fastening devices on the edge of the fan shroud are arranged in the housing. The housing depicted there has a cross arm as a single part that is mounted between the two free arms of the frame, in order to give the housing the necessary rigidity.  
           [0009]    The present invention is directed toward overcoming one or more of the problems set forth above.  
         SUMMARY OF THE INVENTION  
         [0010]    In one aspect of the present invention, a fastening between a fan shroud and a heat exchanger is provided. The fastening includes a plurality of cooperating fastening devices about the outer edge of the shroud and heat exchanger. At least one of the cooperating fastening devices comprises a locking hook on one edge of the shroud, a mount on an edge of the heat exchanger corresponding to the shroud one edge, a stop on the corresponding heat exchanger edge spaced from the mount slot in a direction opposite a first direction, and an elastically flexible extension on the locking hook including a locking tab. The mount defines a slot adapted to receive the locking hook from the first direction. The extension is elastically biased toward an interfering position between the locking tab and the stop when the locking hook is received in the mount slot, and is manually engageable to flex the extension to a releasing position in which the locking tab does not interfere with the stop.  
           [0011]    In one form of this aspect of the present invention, a housing is provided about the edge of the heat exchanger, wherein the mount is on the housing.  
           [0012]    In another form of this aspect of the present invention, the fastening mounts the fan shroud to the front of the heat exchanger, the first direction is generally up and the mount slot is upwardly open and spaced forwardly of the front of the heat exchanger at the corresponding heat exchanger edge, and the locking hook extends laterally from the shroud one edge.  
           [0013]    In a further form, the mount includes a front leg spaced forwardly of a rear leg with the mount slot defined between the legs, and the locking hook includes a lower portion having two arms spaced from the lower portion on opposite sides thereof, the lower portion being receivable between the front and rear legs with the front leg captured between the lower portion and two arms. In one further form, the mount front leg has a tapered upper surface adapted to guide the locking hook toward the heat exchanger when the locking hook is moved down into the mount slot. In a still further form, a continuation on the locking hook is substantially vertically aligned with the locking tab on a side of the locking hook opposite the locking tab, wherein the continuation extends to the mount front leg when the locking hook is received in the mount slot to secure the locking hook against unintended loosening.  
           [0014]    In yet another form of this aspect of the invention, the first direction is generally up and the stop is spaced above the mount slot. In a further form, the stop has a tapered upper surface adapted to flex the locking hook extension past the stop when the locking hook is moved into the mount slot.  
           [0015]    In still another form of this aspect of the invention, at least one other of the cooperating fastening devices comprise a pin and hook.  
           [0016]    In another form, the fan shroud is plastic and the locking hook is a protrusion molded on the one edge of the shroud.  
           [0017]    In yet another form, the heat exchanger is a heat exchanging device and a housing supporting the heat exchanging device in an installation.  
           [0018]    In still another form, the first direction is generally up, and the stop secures the one cooperating fastening device against separation due to relative vertical movement. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]    [0019]FIG. 1 is a perspective view of a heat exchanger with a fan shroud mounted thereon according to the present invention;  
         [0020]    [0020]FIG. 2 is an enlarged perspective view showing the locking hook of FIG. 1 when disassembled;  
         [0021]    [0021]FIG. 3 is an enlarged perspective view showing the locking hook of FIG. 1 when the shroud is assembled on the heat exchanger; and  
         [0022]    [0022]FIG. 4 is a simplified perspective view of a second embodiment of the invention in which a housing supports the heat exchanger with a fan shroud mounted to the housing according to the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0023]    A heat exchanging structure  10  in which the present invention is embodied is illustrated in FIG. 1. The structure  10  includes a heat exchanger  14  (such as a crossflow cooler) having collecting tanks or headers  20 ,  22  arranged vertically on opposite sides of the heat exchanger  14 , with a suitable core  26  extending therebetween. The core  26  may include a plurality of flat tubes  30  with suitable ribs  32  arranged in between (only some of which are shown in FIG. 1).  
         [0024]    The tubes  30  and ribs  32  may be of any suitable design according to the requirements of the structure  10  including, for example, round or flat tubes and/or serpentine or plate fins. Further, the heat exchanger  14  may be of any suitable material including, for example, plastic collecting tanks  20 ,  22 . Moreover, it should be recognized that the heat exchanger  14  with which the present invention may be used may be of virtually any suitable heat exchanging configuration.  
         [0025]    In the illustrated embodiment, an oil cooler  36  is also shown, and may be provided, for example, to cool transmission oil by means of the circulating coolant of the internal combustion engine (not shown).  
         [0026]    A fan shroud  40  made, for example, of plastic is secured in front of the heat exchanger  14  (i.e., when used in a vehicle, in front of the heat exchanger  14  relative to the direction of travel of the vehicle). The fan shroud  40  has a central opening  42  surrounded by a frame  44 . Reinforcing supports  46  may also be provided from the frame  44  to the central opening  44  in stellate fashion.  
         [0027]    A driven fan  48  may be mounted in the central opening  42  in a suitable manner. The fan  48  draws in cooling air during operation through the core  26  of the heat exchanger  14 , whereby heat from a fluid within the heat exchanger tubes  30  may be exchanged/discharged to the air passing over the tube outer walls and fins  32 . When used with a vehicle, the cooling air is blown through the heat exchanger  14  in the direction of the engine compartment, where the cooling air can also be used for additional cooling purposes, and then taken off.  
         [0028]    The oil cooler  36  may also be suitably fastened to the fan shroud  40 .  
         [0029]    In accordance with the present invention, different cooperating fasteners  50  may be advantageously provided around the perimeter of the heat exchanging structure  10  for securing the fan shroud  40  to the heat exchanger  14 . That is, as illustrated in FIG. 1, cooperating fasteners  50   a - c  are provided between end plates  54  at the top and bottom of the heat exchanger  14  and the upper and lower portions of the shroud frame  44 . Further, cooperating fasteners  50   d - f  are provided between the collecting tanks  20 ,  22  and the side portions of the shroud frame  44 .  
         [0030]    It should be appreciated that fastener components secured to plastic components, such as those fasteners components on plastic collecting tanks  20 ,  22  and/or a plastic fan shroud  40 , may be integrally molded with such components so as to consist of a plastic material having a degree of elasticity. It should also be appreciated that the number of fasteners  50   a - f  provided for securing the shroud  40  to the heat exchanger  14  may vary depending on a variety of factors, and that the present invention is not limited to a specific number of such fasteners  50 .  
         [0031]    A number of the fasteners  50   d - e  may consist of an upwardly facing hook-like support formed, for example, on the collecting tanks  20 ,  22  which cooperate with tappet-like protrusions formed on the edge of the fan shroud  40 , whereby the tappet-like protrusions may be lowered into the cooperating hook-like supports when mounting the fan shroud  40  to the heat exchanger  14 . Further, the supports and/or protrusions may be advantageously designed so that tolerances between the heat exchanger  14  and the fan shroud  40  can be compensated.  
         [0032]    A locking fastener  60  may also be advantageously provided at an opening (not shown) in one or more of the fasteners  50   e  on the fan shroud  40  and a blind hole (not shown) in the collecting tank  22 . The fastener  60  may advantageously be located at an accessible site, such as the upper portion of the heat exchanger  14 , so that it can, in the case of disassembly, be readily accessed and removed with a single hand motion.  
         [0033]    The already mentioned upper fasteners  50   a  may be, for example, hooks that extend over the edge of the upper end plate  54 , and the lower fasteners  50   b - c  may be pins on the edge of the fan shroud  40  that are inserted into matching slits in the lower end plate  54 . The upper fasteners  50   a  may be arranged somewhat closer to the collecting tanks  20  or  22  than the lower fasteners  50   b - c.    
         [0034]    [0034]FIGS. 2-3 illustrate details of the fastener  50   f  between the left edge of the fan shroud  40  and the left collecting tank  20 .  
         [0035]    Specifically, a locking hook  70  is suitably supported on the fan shroud  40 , as by three protruding molded legs  72   a - c . The locking hook  70  includes a locking tab  76  facing in the X direction and, at about the same height (Z direction), has a rib  78  extending in the opposite direction. Above the height of the locking tab  76  is a manually engageable extension  80  which may be used to loosen the locking hook  70  as described further below.  
         [0036]    Beneath the locking tab  76 , the locking hook  70  may be advantageously formed in the shape of a “U” or a “C” with two arms  86 ,  88  on opposite sides of the locking hook  70 . As illustrated in FIGS. 2-3, the arms  86 ,  88  form a “C” as viewed from above.  
         [0037]    The fastener  50   f  on collecting tank  20  consist of a mount  90  for the locking hook  70  and a stop  92 , which may be advantageously molded integrally with the collecting tank  20  when made of plastic. The mount  90  consists of two legs  96 ,  98  projecting upwardly from a bottom  100 , with suitable support ribs  104  thereon.  
         [0038]    During mounting of the fan shroud  40 , it is pushed in the direction of the arrow  110  in FIG. 2 (i.e., downward along the Z axis). As the locking hook  70  moves down, the two arms  86 ,  88  of the locking hook  70  first enclose the front leg  98  of the mount  90 . Further, the locking hook  70  beneath its locking tab  76  engages the upper, tapered portion  114  of the stop  92 , causing the locking hook  70  to flex forwardly (away from the stop  92 ) until, in the final position, the bottom of the locking hook  70  is limited by the mount bottom  100 . In that position, the locking tab  76  is beneath the stop  92 , and the locking tab  76  elastically flexes back to its original position, in which case it lies beneath the bottom of the stop  92  and is therefore blocked from being raised up out of the fastened position. Further, the interengagement of the locking hook  70  between the legs  96 ,  98  and the leg  98  between the locking hook arms  86 ,  88  may preferably have only limited play to ensure a secure fastening of the fan shroud  40  to the collecting tank  20 . Moreover, undesirable loosening of the fan shroud  40  (e.g., under the influence of vibrations during operation) is prevented.  
         [0039]    It should also be appreciated that the upper end of the front leg  98  is advantageously tapered, so as to facilitate initial movement of the locking hook  70  onto the mount  90 , and further to permit manual pivoting of the locking hook extension  80  to clear the locking tab  76  from beneath the stop  92  to allow the fan shroud  40  to be moved up to disengage it from the cooling tank  20  (e.g., during disassembly or maintenance). That is, if the fan shroud  40  is to be disassembled, a pressure force may be exerted on the locking hook extension  80  in the direction of the arrow  120  in FIG. 3, whereupon the locking tab  76  is released and the fan shroud  40  can be lifted up clear of the locking hook  70 , supported by continued grasping of the extension  80 . Such a procedure may be advantageously performed without a tool. The end of the extension  80  may therefore advantageously be formed with a cavity  124  for manual handling with a finger.  
         [0040]    Moreover, the fastener  50   f  such as described may be advantageously configured so as to be the only fastener which locks the fan shroud  40  to the heat exchanger  14 , whereby the other fasteners may freely release the shroud  40  when lifted. Accordingly, the shroud  40  may be securely maintained on the heat exchanger  14  and yet may also be easily removed when necessary for disassembly or maintenance. That is, by locating the fastener  50   f  as illustrated, the shroud  40  may be readily disassembled by a single person, without using any tool, by pressure on the locking hook extension  80  and removing the fan shroud  40  upward. Further, this enables the shroud  40  to be securely mounted with a minimal number of fasteners.  
         [0041]    [0041]FIG. 4 shows the principle of another practical example of the present invention in which a housing  130  (which can consist of, e.g., metal or plastic) having suitable supports with damping elements to support a heat exchanger (e.g., the radiator of a vehicle, not shown). The housing  130  has two ends  132  and  134  and a lower crosspiece  136  connecting them. Heat exchangers may be inserted and fastened in the housing  130  in a suitable manner (not shown) including, as is frequently desired, several heat exchangers arranged one behind the other in the direction of cooling air flow. The periphery of an exemplary heat exchanger is shown by the dotted line  140 , and the edge of a fan shroud according to the present invention and its central opening are marked with a dash-dot line  144 ,  146 . Suitable fasteners  50 ′ and a locking fastener  60 ′ such as previously described may be spaced around the periphery of the housing  130 , as may a fastener such as shown in FIGS. 2-3 (with the mount  90 ′ and stop  92 ′ arranged on the left end  132  of the housing  130  and cooperable with a fan shroud locking hook such as previously described). It should be appreciated that a fan shroud such as previously described may advantageously imparts desired rigidity to the housing  130  so that, in contrast to the prior art, an upper crosspiece need not be provided between the ends  132 ,  134 .  
         [0042]    Still other aspects, objects, and advantages of the present invention can be obtained from a study of the specification, the drawings, and the appended claims. It should be understood, however, that the present invention could be used in alternate forms where less than all of the objects and advantages of the present invention and preferred embodiment as described above would be obtained.