Abstract:
An impeller assembly including a pair of plates with one of the plates having a plurality of blades and an interlock structure for aligning and coupling the plates together. A disclosed example of the interlock structure includes a plurality of latch members extending from one plate and locking into apertures of the other plate. The interlock structure may also include a plurality of channels engaging the blades. The blades of the impeller may engage a pair of latch members in a saddle manner. A method of using the impeller assembly within an air blower is also disclosed.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims priority under 35 U.S.C. 119(e) from provisional U.S. Patent Application No. 60/893,349 filed Mar. 6, 2007 the contents of which are incorporated herein by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates to impeller devices for moving fluids. More specifically, the invention relates to the assembly of impeller components. 
       BACKGROUND OF THE INVENTION 
       [0003]    Impellers are a rotating component of a pump, fan, or other device that moves fluids. Impellers transfer energy from a prime mover to a fluid. A radial impeller forces the fluid generally outwards from the center of rotation. There are several types of impellers that are commonly found in various operations. One type of impeller uses one shroud which is a backplate mounted on the side of the blades opposite to the side of the impeller where the air enters. A second type uses two shrouds, a backplate and a cone that is mounted on the side of the blades where the air enters the impeller. A third type uses a single backplate in the center of the blades and two cones on the ends of the blades. 
         [0004]    Impellers that have both a backplate and a wheel cone typically have blades between the plates. In many applications, the blades are formed integrally with one or both cover plates. Fluid to be pumped is introduced into the impeller housing at one side thereof. The shaft rotates so as to rotate the impeller thereby creating regions of high and low pressure within the impeller housing and impelling fluid through the assembly. 
         [0005]    Both impellers with cones and without cones have advantages and disadvantages relative to each other. It is less expensive to manufacture impellers without cones but they require tighter assembly tolerances for fans with low specific speeds. Impellers with cones are significantly more expensive to manufacture as they require welding or other time intensive manufacturing processes to form them. Further, the welding or connection point of the cone to the impeller is often the weakest link of the impeller. However, they are usually more efficient than impellers without cones especially for impellers with low specific speeds. 
       BRIEF SUMMARY OF THE INVENTION 
       [0006]    The present invention is directed to an apparatus and method for forming a closed faced impeller. In one example, a pair of plates is provided with one of the plates being adapted for coupling to a shaft means and the other plate having a concentric aperture adapted to pass a fluid there through. One of the pair of plates is provided with a plurality of blades for engaging a fluid. Preferably the blades are formed integrally with a plate. Alternatively, the blades may be formed on a separate backplate which is disposed between the upper and lower cover plates. The other pair of plates is provided with a plurality of blade interlocks adapted to couple the upper and lower cover plates together. In one embodiment, the interlocks are defined as resilient latches. 
         [0007]    The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0008]    For a more complete understanding of the present invention, reference is now made to the following descriptions taken in conjunction with the accompanying drawing, in which: 
           [0009]      FIG. 1  is an isometric view of an impeller assembly according to one embodiment of the invention; 
           [0010]      FIG. 2  is an isometric view of the backplate portion of the impeller assembly of  FIG. 1 ; 
           [0011]      FIG. 3  is an isometric view of the backplate portion of the impeller assembly of  FIG. 1 ; 
           [0012]      FIG. 4  is an isometric view of the cover plate portion of the impeller assembly of  FIG. 1 ; 
           [0013]      FIG. 5  represents an enlarged portion of  FIG. 4  as indicated by circle, C 5 ; 
           [0014]      FIG. 6  represents an enlarged portion of  FIG. 5  as indicated by circle, C 6 ; 
           [0015]      FIG. 7  is a cross sectional view of a portion of the impeller assembly of  FIG. 1 ; 
           [0016]      FIGS. 8 and 9  are a cross sectional views of the impeller assembly of  FIG. 1 ; 
           [0017]      FIG. 10  is a blower apparatus incorporating an impeller assembly of  FIG. 1 ; and 
           [0018]      FIG. 11  is the blower apparatus of  FIG. 10  with a portion removed. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0019]    Referring to the drawings,  FIG. 1  illustrates an impeller  100  according to one example of the present invention. Impeller  100  includes a lower backplate  10 , an upper cover plate  12  and a plurality of blades  14  between the plates  10 ,  12 . In the context of this specification, the terms “upper” and “lower” do not indicate a particular orientation of the components or assembly, or a particular relative position, but are employed for distinguishing purposes. 
         [0020]    Referring to  FIG. 2 , blades  14  of backplate  10  may be formed integrally on an upper surface face of backplate  10 . Backplate  10  may be of pressed metal construction or manufactured from a polymeric material. In the illustrated embodiment, at least a portion of the blades  14  are of sufficient height to extend between the backplate  10  and cover plate  12 , and so form passageways between backplate  10  and cover plate  12 . During impeller operation, fluid is moved from the center of the impeller to the outer edge of the impeller via the passageways. Blades  14  may be radially aligned (as shown in this example) or involute and serve to create regions of high and lower pressure within the impeller assembly during impeller operation, so as to impel fluid through the impeller assembly 
         [0021]    Backplate  10  also includes a center hub  22  with blades  14  extending in a generally radial manner from center hub  22  to an outer edge  26  of backplate  10 . Backplate  10  includes a center aperture  28  adapted to receive a drive shaft (not shown). Center aperture  28  may be splined or include other coupling structures useful to transfer torque from a drive shaft to impeller assembly  100 . In another example of the invention, center hub  22  may be separated from blades  14 . 
         [0022]    In the illustrated embodiment, each blade  14  includes a generally flat ridge portion  30  and a downwardly tapering portion  32  which extends toward the outer edge  26  of backplate  10 . Each blade  14  of backplate  10  also defines a pair of generally flat blade side surfaces  33 ,  34 . Blade  14  also includes apertures  36 , each defined near the base of blade  14 . Apertures  36  are sized to receive portions of an interlock structure of cover plate  12  as described hereinafter. 
         [0023]      FIG. 3  is an illustration of backplate  10  of  FIG. 2  and illustrates the generally radial nature of aperture  36  locations relative to center aperture  28 . 
         [0024]    Referring to  FIG. 4 , cover plate  12  includes a central aperture  39  through which fluid passes during impeller operation. Cover plate  12  includes an interlock structure for coupling the backplate  10  to the cover plate  12 . In this example, the interlock structure includes a plurality of torque transfer components  40  and a plurality of latch members  42 . In the example of  FIG. 4 , torque transfer components  40  are radially aligned and spaced and sized to receive upper portions of blades  14  upon assembly. Channels  44  of torque transfer components  40  are shown as continuous channels, while in alternative embodiments, the channels  44  may be broken. The torque transfer components  40  are of sufficient integrity so as to transfer some of the torque applied to backplate  10  to cover plate  12  during impeller rotation. Another purpose of torque transfer components  40  is to align backplate  10  with cover plate  12  during assembly 
         [0025]      FIG. 5  represents an enlarged view of  FIG. 4  as represented by circle, C 5 , in  FIG. 4 . In this example, latch members  42  are shown as a pair of extending tines with detents  50  at uppermost portions of the tines. Latch members  42  are resilient and allow each tine to deflect away from each other during impeller assembly. Detents  50  are sized and shaped to cooperate with apertures  36  so as to lock the cover plate  12  to the backplate  10 . As 
         [0026]      FIG. 6  represents an enlarged view of  FIG. 5  as represented by circle, C 6 , in  FIG. 5 . Pairs of tines of latch members  42  include opposed surfaces  52  at detents  50 . Surfaces  52  of latch members  42  engage a portion of blade  14  within apertures  36 , as shown by  FIG. 7  which is a cross sectional view taken generally perpendicular to a base surface of impeller  100 . 
         [0027]    During assembly of impeller  100 , backplate  10  and cover plate  12  are aligned and brought together so that tines of latch members  42  engage blades  14  and deflect away from blades  14  until detents  50  engage flat surfaces  59  of apertures  36 , whereupon the times return to position. At the same time, channels  44  of the torque transfer components  40  engage the sides  33 ,  34  of blades  14  as the backplate and cover plate are brought together. As shown in  FIG. 8 , the resilient latch members  42  have snapped into the apertures  36  to hold the cover plate  12  and backplate  10  during rotation such that separation of the two components is minimized. 
         [0028]      FIG. 8  also illustrates the relationship between a curved portion  80  of cover plate  12  and a correspondingly curved section within downwardly tapering portions  32  of back plate  10 . As a consequence cover plate  12  engages back plate  10  throughout the tapering portion  32  of back plate  10 . 
         [0029]      FIG. 9  is another cross sectional view of the example of the invention showing the mating relationship between blades  14  of backplate  10  and channels  44  of cover plate  12 . 
         [0030]      FIG. 10  illustrates an example of a blower apparatus incorporating impeller  100 . Housing  60  defines a aperture  61  into which impeller  100  is located. Housing  60  includes a fluid inlet  62  and a fluid outlet  63 . Conduits of a fluid system (not shown) are in fluid communication with inlet  62  and outlet  63 .  FIG. 11  is a cross-sectional illustration of the blower apparatus of  FIG. 10 . A drive shaft is coupled to the impeller at hub  22 . As the drive shaft is rotated, impeller  100  rotates within housing  60  drawing fluid from inlet  62  and through the impeller  100  prior to exit at outlet  63 . Some amount of torque supplied by drive shaft at backplate  10  effectively is transferred via the blades  14  and torque transfer components  40 . 
         [0031]    In alternative examples of the invention, the torque transfer components and latch members may be combined. In another example, the torque transfer components may engage only a single side of the blades, instead of opposed sides of the blades as disclosed herein. Torque transfer components are preferably configured to engage one or more surfaces of the blades. Torque transfer components may assume different sizes or shapes, though a smaller profile is desirable to minimize disturbances to fluid flowing through the impeller. 
         [0032]    In another example of the invention, latches extend from backplate  10  and engage apertures or cavities of cover plate  12 . In another example, detent surfaces similar to surfaces  52  of the aforementioned example may engage a back surface of backplate  10  instead of blades  14 . Other examples of the present invention may include fewer latch members than blades  14  or an even number of blades  14 . In another example of the invention, the latch members would not make contact with the sides  33 ,  34  of blades  14 , but instead be located between adjacent blade  14  pairs. In yet another example of the invention, the latch members may be outwardly inclined as opposed to inwardly inclined as in the example of  FIG. 4 . In another example, latch members may extend into generally perpendicular contact with the backplate relative, for example, to a back surface of the backplate  10 . In another example of the invention, the latches  42  could be pinned in place, secured with threaded fastener(s), or coupled in other means. 
         [0033]    Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.