Abstract:
A motor-driven blower, particularly suited for carpet cleaners and other wet vacuuming appliances, includes a rotating separator cup to impede water droplets and foam from being drawn into the blower. The separator cup is removably connected to a spider bracket that is mounted more permanently to one end of the motor shaft. Since the separator cup is not directly connected to the motor shaft, the cup can be removed without disturbing the rest of the blower. Thus, the blower can be run either with or without the separator cup. Moreover, by not attaching the separator cup directly to the motor shaft, the shaft can be made shorter to minimize vibration and noise at high rpm&#39;s.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The subject invention generally pertains to motors for vacuum equipment and more specifically to a gas/liquid separator for such a motor. 
   2. Description of Related Art 
   Motor-driven fans for creating a vacuum in equipment known as wet/dry shop vacs, wet carpet cleaners, water filtration units, water extractor units, etc., are exposed to a significant amount of moisture-laden air or foam. To reduce the amount of moisture drawn into the fan and/or motor, a rotating separator can be attached to the end of the motor shaft at the fan&#39;s inlet. A typical separator includes a series of peripheral fins that centrifugally sling water droplets outward away from the fan&#39;s inlet while allowing the air, which is lighter than the droplets, to enter the fan by passing between the fins. 
   Examples of such separators are disclosed in U.S. Pat. Nos. 6,391,101; 6,174,350; 6,162,287; 5,902,386; 5,096,475; 5,090,974; 5,030,257; 2,945,553; 2,221,572; and 2,102,353. Although these patented separators may be effective for their intended purpose, they all seem to have at least one of the following drawbacks. 
   One, in order to attach the separator to the end of the motor shaft, the shaft may need to be extra long to extend beyond its bearings so that one end of the shaft can extend through the separator and attach to the separator&#39;s end cap. Since many vacuum motors run at over 20,000 rpm, such an overextended shaft is more easily bent and may tend to vibrate, especially when the end of the shaft carries the weight of a separator. 
   Two, when the separator is fastened to the motor shaft by a nut screwed onto the end of the shaft, removing the separator for periodic cleaning involves removing two parts, the nut and the separator. Although that may not seem like a significant problem, the nut is a relatively small part that may be accidentally dropped and lost in the dirt/water receptacle of the vacuum equipment. 
   Three, if the nut not only fastens the separator to the motor shaft but also fastens other parts to the shaft, such as an impeller, sleeve, seal, spider bracket, etc., then the separator may be required in order to properly assembly and run the motor. Not being able to run the motor without the separator can be a disadvantage in dry vacuum applications where the separator is not needed. Thus, a company that manufactures motors for vacuum equipment manufacturers may need to produce one type of motor shaft for dry applications and another, longer motor shaft for wet applications. 
   Four, having a motor shaft with a fixed length extension for holding a separator of a particular size limits a motor manufacturer&#39;s freedom to vary the design of the separator to meet the particular needs of their customers (e.g., vacuum equipment manufacturers). Some customers may want a motor with a tall, narrow separator, and others may want one with a much shorter separator. 
   Consequently, a need exists for a separator design that allows motor manufactures to vary the shape of the separator or even omit the separator altogether to meet the needs of their customers without having to also change the design of the motor shaft. 
   SUMMARY OF THE INVENTION 
   One object of some embodiments of the invention is to provide a separator design that accommodates separator cups of various shapes without having to change the motor shaft to which the separator cup attaches. 
   Another object of some embodiments is to provide a motor with a rotatable separator cup that can be removed without tools or without having to remove additional parts such as a nut. 
   Another object of some embodiments is to minimize a motor shaft&#39;s extension beyond its support bearings by not having the very end of the shaft directly connected to the separator cup. 
   Another object of some embodiments is to minimize the part count of a motor with a separator. 
   Another object of some embodiments is to provide a motor that can be run either with or without the separator cup. And when run without the separator cup, the motor shaft does not protrude a significant distance beyond the end of the motor housing or the shaft&#39;s support bearings. 
   Another object of some embodiments is to provide a motor with a separator, wherein the length of the motor shaft is minimized to reduce vibration, reduce noise, increase motor life, and increase efficiency. 
   Another object of some embodiments is to provide a separator assembly with an integral twist-on connection that allows the separator cup to be readily installed and removed from the motor. 
   Another object of some embodiments is to provide a separator assembly with an integral snap-on connection that allows the separator cup to be readily installed and removed from the motor. 
   Another object of some embodiments is to provide a separator assembly that includes a plastic separator cup and a metal spider bracket so that the separator cup is lightweight for minimizing its potential for creating an imbalance, and the spider bracket is relatively rigid and dimensionally stable for holding the separator cup at a properly centered location to minimize vibration. 
   One or more of these and/or other objects of the invention are provided by a motor-driven blower that includes a removable separator cup and a more permanently mounted spider bracket to which the separator cup can be attached. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a cross-sectional view taken along line  1 - 1  of  FIG. 2 . 
       FIG. 2  is a bottom view of a motor-driven blower with a removable separator cup. 
       FIG. 3  is a perspective view of the blower of  FIG. 1  installed in a vacuum appliance. 
       FIG. 4  is a perspective view of a spider bracket used in the blower of  FIG. 1 . 
       FIG. 5  is a cross-sectional side view similar to  FIG. 1  but showing the separator cup disconnected from the rest of the blower. 
       FIG. 6  is a partial cross-sectional view taken along line  6 - 6  of  FIG. 2 . 
       FIG. 7  is a partial cross-sectional side view similar to  FIG. 1  but of another embodiment. 
       FIG. 8  is a partial cross-sectional side view similar to  FIG. 5  but showing the embodiment of  FIG. 7 . 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to  FIGS. 1 and 2 , a motor-driven blower  10  for moving air  12  and separating moisture or water droplets  14  therefrom includes a rotating separator cup  16  attached to a spider bracket  18 . Bracket  18  is attached to the blower&#39;s rotor shaft  20  so that as shaft  20  rotates an impeller  22  for forcing air  12  from an inlet opening  24  to a discharge outlet  26 , shaft  20  also rotates spider bracket  18  and separator cup  16 . Fins  28  on separator cup  16  centrifugally sling water droplets  14  outward away from inlet  24  while allowing air  12 , which is lighter than the droplets, to enter inlet  24  by passing through a plurality of separator openings  30  between the fins. In a currently preferred embodiment, blower  10  can be for a vacuum appliance  32  ( FIG. 3 ) such as a wet/dry shop vac, wet carpet cleaner, water filtration unit, water extractor unit, etc. Additional information about separator cup  16  and spider bracket  18  will be explained after a brief description of other components of blower  10 . 
   Although the structural details of blower  10  may vary greatly, in this particular example blower  10  comprises a stator  34 , a rotor  36  that includes a commutator  38  and rotor shaft  20 , a motor housing  40  made of plastic or some other material, and a commutator bracket  42  also made of plastic or some other material. Housing  40  may comprise an outboard housing section  40   a  attached to an inboard housing section  40   b . Two tie rods  44  are each threaded at one end so that they can screw into housing  40  for clamping stator  34  between housing  40  and bracket  42 . 
   Commutator  38  on rotor shaft  20  is engaged by a pair of commutator brushes (not shown) to deliver electrical current to the rotor. The commutator brushes can be of any type including, but not limited to, those that are well known to those of ordinary skill in the art. The brushes, for example, can be carbon bars that are spring biased radially against commutator  38 . 
   An inboard bearing  46  in housing  40  and an outboard bearing  48  in bracket  42  supports the rotor within stator  34 . An annular bearing retainer  50  made of sheet metal is attached to housing  40  by way of a bearing retainer fastener  52 . Bearing retainer fastener  52  represents any fastener for holding bearing retainer  50  to housing  40 . Examples of fastener  52  include, but are not limited to, a rivet, a screw and nut assembly, a self-tapping screw, etc. 
   A threaded nut  54  screws onto an inboard end  56  of shaft  20  to clamp impeller  22  and spider bracket  18  between nut  54  and inboard bearing  46  that is axially backed by a shoulder  58  on shaft  20 . For multistage blowers, a stack of two or more axially offset impellers could be clamped between nut  54  and bearing  46 . Nut  54  may also clamp a sleeve  60  that axially positions impeller  22  within housing  40 . Impeller  22  may comprise a series of fan blades  62  interposed between an ouboard fan disc  64  and an annular inboard fan disc  66 . In this example, nut  54  clamps outboard fan disc  64  between sleeve  60  and a hub  68  of spider bracket  18 . To do this, spider bracket  18  extends through a suction opening  70  of inboard fan disc  66 . 
   Alternatively, nut  54  could be omitted by providing hub  68  with a threaded hole so that hub  68  can screw onto shaft  20  in place of nut  54 . In that case, hub  68  would clamp impeller  22  (and sleeve  60 ) between bearing  46  and spider bracket  18 . 
   Referring to  FIG. 4 , spider bracket  18  has a plurality of spokes  72  and a plurality of spider bracket openings  74  between hub  68  and an outer perimeter  76  of bracket  18 . Spider bracket openings  74  permit air  12  to enter the blower. 
   Referring to  FIG. 5 , separator cup  16  comprises an end cap  78 , a rim  80 , and a sidewall  82  extending between cap  78  and rim  80 . Sidewall  82  defines the plurality of separator openings  30  between fins  28 . In some cases, an annular rib  85  helps reinforce sidewall  82 . 
   To either attach or remove separator cup  16  from spider bracket  18 , the cup/bracket assembly (i.e., cup  16  and bracket  18 ) includes a disconnectable joint  84  between rim  80  and outer perimeter  76 . Joint  84  permits separator cup  16  to be separated from spider bracket  18  without diminishing the blower&#39;s ability to move air  12 , whereby blower  10  can be operated either with or without separator cup  16 . Joint  84  can achieved by any of a variety of fastening systems including, but not limited to releasable tabs, clips, snaps, pins, screws, threaded fasteners, threads between cup  16  and bracket  18 , friction, wedge connection, etc. 
   In a currently preferred embodiment, joint  84  is a twist-on connection  86  that permits removing cup  16  from spider bracket  18  by rotating cup  16  relative to bracket  18 . The term, “twist-on” refers to a connection where two parts can be joined or separated by rotating one relative to the other and preferably but not necessarily by rotating less than one full turn.  FIG. 5  illustrates that when even cup  16  is removed, the remainder of blower  18  is still intact and fully functional to move air  12 . 
   In the preferred embodiment, spider bracket  18  includes a plurality of fingers  88  that protrude through openings  90  or slots in rim  80  and engage a plurality of finger-engaging surfaces  92 . Fingers  88  are integral extensions of spider bracket  18  such that fingers  88  and the rest of bracket  18  are a unitary piece. Likewise, finger-engaging surfaces  92  are an integral part of separator cup  16  such that surfaces  92  and the rest of cup  16  comprise a unitary piece. Thus, separator cup  16  can be installed and removed from bracket  18  without tools and without having to handle a separate fastener dedicated to holding cup  16  and bracket  18  together. 
   Although fingers  88  are shown extending from spider bracket  18 , alternatively, similar fingers could extend from the separator cup and overlay finger-engaging surfaces on the spider bracket that could include openings or slots similar to openings  90 . 
   To help maintain the concentric alignment and thus the balance of the separator and spider bracket assembly, separator cup  16  and spider bracket  18  include mating beveled surfaces  94  and  96  respectively. 
   Referring to  FIG. 6 , the contact surfaces or interface between fingers  88  and surfaces  92  lie at a frictionally self-holding shallow angle of less than ten degrees and ideally at two degrees. Fingers  88  preferably point in a direction opposite to that of the shaft&#39;s direction of rotation so that starting blower  10  tends to tighten rather than loosen connection  86 . When installing separator cup  16 , the relative rotation and axial movement of cup  16  is represented by arrows  98  and  100  respectively, and the normal rotation of the rotor is represented by arrow  102 . 
   In operation, impeller  22  forces air  12  to travel in series through separator openings  30 , spider bracket openings  74 , inlet opening  24 , across fan blades  62 , through discharge opening  26 , and then to atmosphere. Although air  12  travels in series through openings  30 ,  74  and  24 , the flow is not necessarily in that order. Spider bracket openings  74 , for instance, could either be upstream or downstream of inlet opening  24 , depending on how far the spoke portion of spider bracket  18  protrudes past housing  40   a  in an axial direction. 
   Other features of separator cup  16  include end cap  78  being of a smaller diameter than that of the cup&#39;s rim  80 , which makes cup  16  easier to manufacture by way of a plastic injection molding process. Also, end cap  78  can be hole-free because there is no need for shaft  20  to protrude through cap  78 . A hole-free end cap provides separator cup  16  with a cleaner appearance. 
   In another embodiment, shown in  FIGS. 7 and 8 , a spider bracket  18 ′ replaces spider bracket  18 , and separator cup  16 ′ replaces cup  16 . The assembly of bracket  18 ′ and cup  16 ′ includes a disconnectable joint  104  made possible by way of a snap-on connection  106  that permits installing or removing separator cup  16 ′ from spider bracket  18 ′. The term, “snap-on” refers to a connection that involves resilient deflection of at least one of two mating parts. In this case, a latch  108  can resiliently deflect to reach around and engage a backside  110  of spider bracket  18 ′. Latch  108  is an integral extension of separator cup  16 ′ so that latch  108  and the rest of cup  16 ′ is a unitary piece. Although latch  108  includes an edge  112  that points radially inward to engage the backside of spider bracket  18 ′, it is conceivable to have latch  108  protrude through openings in spider bracket  18 ′ and have the latch&#39;s edge point outward rather than inward to engage the backside of bracket  18 ′. 
   Although the invention is described with reference to a preferred embodiment, it should be appreciated by those of ordinary skill in the art that various modifications are well within the scope of the invention. In some cases, for example, at least some portion of outer perimeter  76  protrudes radially beyond at least some portion of rim  80  so that one hand can manually grip the protruding portion of perimeter  76  to hold spider bracket  18  stationary while the other hand can untwist and remove cup  16  from spider  18 . Therefore, the scope of the invention is to be determined by reference to the following claims.