Abstract:
A vacuum cleaner having a main body and a handle, the main body being formed with a nozzle which delivers a stream of dirt-laden air through a dirt duct through a motor-fan inlet, the handle being supported on the motor-fan assembly and housing a filter bag which communicates with the motor-fan assembly for receiving the dirt-laden air, the motor-fan assembly having a motor housing, a motor with commutated brushes which give off carbon dust particles, a motor cooling fan for drawing a cooling airstream and a working fan for drawing the dirt-laden air, the vacuum comprising: an opening formed in the motor housing for receiving the cooling airstream; a cooling outlet formed in the motor housing through which the cooling airstream exists; means for directing the existing cooling airstream into the dirt-laden air; a collar extending axially outwardly from the motor housing, the collar allowing pivotal rotation of the motor housing relative to the main body.

Description:
TECHNICAL FIELD 
     The present invention relates generally to a motor-fan assembly in an upright vacuum cleaner. More particularly, the present invention relates to a motor-fan assembly that directs the cooling air from the motor-fan assembly into a filter bag of a vacuum cleaner. 
     DISCLOSURE OF INVENTION 
     In the vacuum cleaner art, a motor-fan assembly is typically used as a vacuum source for drawing dirt laden air through a nozzle formed in the main body of the vacuum cleaner and directing that air into a filter bag. Known motor-fan assemblies, therefore, have a fan driven by a motor that draws the dirty working air into the motor housing and expels the dirty air through a motor fan outlet into the filter bag. To cool the motor, a cooling fan draws relatively cool air though an intake, across the components of the motor for cooling thereof before expelling the heated air out an exhaust vent. During its passage across the components of the motor, the cooling air may pick up particles discharged by the motor such as carbon or copper particles and carry these particles out the exhaust vent. 
     To prevent the venting of these particles into the atmosphere, it is known to route the cooling air into the working air intake, thus routing the cooling air into the filter bag along with the working air. In this manner, the particles discharged by the motor are captured in the filter bag. To perform the carbon capture, it is known to provide a vacuum cleaner motor within a fixedly mounted casing formed with a plurality of air inlets or vents. The motor drives a working fan which communicates with and draws air through a vacuum chamber. A channel extends between the motor housing compartment and the vacuum chamber creating a passage for the cooling air to be drawn into the vacuum chamber. As the working fan rotates within the fan compartment, a partial vacuum is created within the chamber which either by itself or in cooperation with a cooling fan draws the cooling air through the air inlets and is drawn into the motor casing to cool the motor. This air then flows through the channel into the vacuum chamber where it is discharged through a dirty air duct and into a vacuum cleaner filter bag. 
     Heretofore, these prior art arrangements that direct the cooling air, into the filter bag have been adequate for the purpose for which they are intended, however in many upright vacuum cleaners the motor-fan casing is attached to the upper housing of the vacuum cleaner and rotates relative to the foot of the vacuum cleaner. Because the prior art arrangements were incorporated into vacuum cleaners having a stationary motor-fan casing, these prior art arrangements are not suitable for uprights wherein the motor hosing rotates relative to the foot, as a constant communication must be maintained between the exhaust vents of the rotating motor casing and the stationary working air ducts of the foot. 
     Therefore, the need exists for an upright vacuum cleaner which directs cooling air from the motor-fan assembly into the filter bag yet permits rotational movement between the motor-fan casing and the foot. 
     SUMMARY OF THE INVENTION 
     The present invention, therefore provides, an improved vacuum cleaner having a main body and a handle. The main body being formed with a nozzle which delivers a stream of dirt-laden air through a dirt duct into a motor-fan inlet. The handle being supported on the motor-fan assembly and housing a dirt collecting container which communicates with the motor-fan assembly via an outlet for receiving the dirt-laden air. The motor-fan assembly includes a motor housing, a motor with commutator brushes which give off carbon dust particles, a motor cooling fan for drawing a cooling airstream and a working fan for drawing the dirt-laden airstream. An opening is formed in the motor housing for receiving the cooling airstream. A cooling outlet is formed in the motor housing through which the cooling airstream exits the motor housing. A duct directs the existing cooling airstream into the dirt-laden airstream and includes a sleeve extending axially outwardly from the motor housing. The sleeve allows for pivotal rotation of the motor housing relative to the main body. 
     The present invention further provides a motor fan assembly in a vacuum cleaner which includes a motor having commutator brushes located within a motor housing. The motor housing has a cooling inlet located near the commutator brushes, a working air inlet, and a working air outlet formed therein. The working air outlet fluidly communicates with the working air inlet and a working fan is positioned between the working air inlet and working air outlet. The working fan is driven by the motor wherein the working fan draws dirt laden working air into the motor housing through the working air inlet and blows the working air out of the motor housing through the working air outlet. A cooling outlet is formed opposite the working air inlet, wherein cooling air entering the cooling inlet exits the motor housing through the cooling outlet. A duct is rotatably supported on the motor housing adjacent said cooling outlet and communicates with the cooling outlet and the working air inlet, whereby air exiting the cooling outlet is directed into the dirt laden airstream and blown out the working air outlet to a dirt collecting container. 
     The present invention further provides a motor-fan assembly for a vacuum cleaner which includes a motor housing having a cooling air inlet, a working air inlet, and a working air outlet formed therein. The working air outlet fluidly communicates with the working air inlet. A motor is positioned within the housing having a motor shaft. A cooling fan is positioned adjacent the cooling air inlet and is coupled to the motor shaft. The cooling fan draws cooling air into the motor housing through the cooling air inlet to cool the motor. A working fan is positioned between the working air inlet and the working air outlet and is coupled to the shaft. The working fan drawing working air into the motor housing through the working air inlet and blows the working air out of the motor housing through the working air outlet. At least one hole is formed in the working fan allowing the cooling air to flow through the working fan and be blown out the working air outlet. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a complete understanding of the objects, techniques and structure of the invention, reference should be made to the following detailed description and accompanying drawings wherein: 
     FIG. 1 is a perspective view of an upright vacuum cleaner; 
     FIG. 2 is a perspective view of a prior art motor fan assembly; 
     FIG. 3 is a side elevational view of the prior art motor fan assembly of FIG. 2; 
     FIG. 4 is a sectional view of the main body of the vacuum cleaner, of FIG. 1 depicting the internal components of the prior art motor fan assembly of FIG. 2; 
     FIG. 5 is a perspective view of a first embodiment of a motor fan assembly according to the present invention; 
     FIG. 6 is a side elevational view thereof; 
     FIG. 7 is a perspective view of a second embodiment of a motor fan assembly according to the present invention; 
     FIG. 8 is a side view thereof; 
     FIG. 9 is a perspective view of a first embodiment of a duct for capturing cooling air exiting the motor fan assembly depicted in FIGS. 5 and 6; 
     FIG. 10 is a perspective view similar to FIG. 7 showing a second embodiment of the duct; 
     FIG. 11 is a perspective view of the assembled first embodiment of the motor fan assembly and first embodiment of the duct; 
     FIG. 12 is a top elevational view of the main body of the vacuum of FIG. 1 with the motor cover and handle removed depicting the first embodiment of the duct in section and a portion of a working air inlet broken away to show the communication of the duct and inlet and further depicting the captured flow of cooling air entering the working air inlet; 
     FIG. 13 is a sectional view taken along line  11 — 11 , FIG. 10 depicting the cooling airstream exiting the duct and being drawn into the working fan; 
     FIG. 14 is a perspective view of a second embodiment of the motor fan assembly; 
     FIG. 15 is a side elevational view thereof;. 
     FIG. 16 is a sectional view of the main body of the vacuum cleaner of FIG. 1 depicting the internal components of the second embodiment of the motor fan assembly and further depicting the path of the cooling air; 
     FIG. 17 is a left side elevational view of the motor fan assembly depicted in FIGS. 12-14 with the working end of the housing and fan removed showing holes within the housing wall that allow the cooling air to exit the motor chamber and enter the working fan chamber; and 
     FIG. 18 is a left side elevational view similar to FIG. 15 with the fan in place depicting the flow of cooling air though the holes in the fan and out of the working chamber through an outlet. 
    
    
     Similar numerals refer to similar parts throughout the drawings. 
     DETAILED DESCRIPTION OF THE INVENTION 
     A conventional vacuum cleaner is shown in FIG.  1  and is indicated generally at  5 . It will be understood that vacuum cleaners are well known in the art and thus vacuum cleaner  5  will be described in general terms. With reference to FIG. 13, vacuum cleaner  5  includes a conventional floor engaging main body or foot  6  having a nozzle  7  formed with a nozzle opening  8 . An agitator  9  is rotatably mounted within nozzle  7 . A dirt duct  10  is formed in main body  6  and communicates at one end with nozzle  7  and at an opposite end with a vacuum generating means in the form of a motor-fan assembly  20 . The motor-fan assembly  20  communicates with dirt duct  10  to draw a flow of dirt laden air, indicated by arrows A, through the main body  6  and into a dirt collecting filter bag  24  (FIG.  1 ). Filter bag  24  is housed within a vacuum cleaner upper housing  22  (FIG.  1 ). Referring back to FIG. 13, a vacuum pressure is generated at the nozzle  7  to draw dirt and debris loosened from a floor surface by agitator  9  through the nozzle opening  8  and dirt duct  10 . The motor-fan assembly  20  then transmits the dirt laden air from the main body  6 , through an air duct  26  and into the dirt collecting filter bag  24  which communicates with air duct  26 . 
     The dirt collecting filter bag is formed of an air pervious material such as, for example, paper or cloth and functions to filter all the dirt laden air and collect the dirt, dust and other particles therein. Alternatively, the dirt laden air may be blown into a container or dirt cup that is largely impervious to air with the exception of an opening that communicates externally of the dirt cup through a filter. Typically in this type of bagless vacuum cleaner a cyclonic action is used in combination with a filter for separating the particulate and traping these particles within the dirt cup. For simplicity, a dirt cup and a filter bag will be referred to generally as filter bag. Referring to FIG. 1, the filter bag may be supported on a substantially vertically extending pivoting handle  28 . Motor-fan assembly  20  is rotatably supported within the main body  6  and may further be provided with a detent  32  (FIGS. 2 and 3) for restricting the rotation of motor-fan assembly  20  which, in turn, restricts the rotation of handle  28 . 
     Referring specifically to FIG. 4, motor fan assembly  20  includes a motor housing  34  which encloses a motor  35 . Motor  35  includes a field coil, diagrammatically represented at  36 , a commutator  37  and a pair of carbon brushes  39  which ride on the commutator  37  to connect the rotor coil to a stationary circuit by a near frictionless contact, as is known in the art. Motor  35  rotatably drives a shaft  42  to which a working fan  45  is suitably coupled such that the working fan  45  rotates with shaft  42 . Working fan  45  may be separated from motor  35  by a wall  47  substantially defining a working fan chamber  49  between the wall  47  and housing  34 . A working air inlet  50  is formed within the housing  34  near working fan  45  for receiving the dirt laden air. Working air inlet  50  communicates with nozzle opening  8 , such that, when the motor  35  drives fan  45 , the fan  45  draws dirt laden air through nozzle opening  8  and dirt duct  10  and blows the dirt laden air or working air out air duct  26 , as shown by arrows A of FIG.  4 . 
     Referring still to FIG. 4, as motor  35  rotates within housing  34 , heat is generated between the commutator  37  and carbon brushes  39  as well as between the armature and field winding of motor  35 . To prevent overheating of motor  35 , a cooling fan  52  is provided on the end of shaft  42  opposite working fan  45 . Cooling fan  52  draws a stream of cooling air, indicated by arrows B of FIGS. 2 and 4, into housing  34  through a plurality cooling air inlets  55  (FIG. 2) formed in a front face  56  of the motor housing  34 . The cooling air flows across commutator  37 , carbon brushes  39 , field coil  36  and the armature of motor  35  and is expelled from motor housing  34  through a plurality of exhaust openings  58  (FIGS. 2 and 3) which are formed in an exhaust end  59  of motor housing  34 . Exhaust end  59  is located on an end of housing  34  opposite working air inlet  50 . As shown in FIGS. 2 and 3, a collar  63  extends outwardly from the exhaust end  59  of housing  34  and includes a plurality of radially extending support ribs  64 . A stepped portion  65  extends outwardly from the center of collar  63  and include a plurality of radially extending support ribs  66 . Exhaust openings  58  are formed between ribs  64  of collar  63  and ribs  66  of stepped portion  65 . As the commutator turns and is contacted by the carbon brushes, the brushes emit carbon dust which gets picked up by the cooling air and blown out exhaust openings  58 . 
     In accordance with the invention, it is desirable to capture this cooling air exhaust and the carbon particles contained therein and filter the carbon dust laden cooling air through the filter bag  24 . One embodiment of a motor fan assembly which provides for directing the cooling air exhaust into a filter bag is shown in FIGS. 5-8 and  11 - 13  and is indicated generally at  70 . Motor fan assembly  70  is substantially similar to motor fan assembly  20  and includes a cooling air inlet opening  72  (FIG. 5) formed in the front face  56  of motor housing  34 . The inlet opening  72  is located substantially over the commutator  37  and carbon brushes  39  so as to specifically direct the cooling air across the commutator and brushes to reduce the heat created there between. By pinpointing the hottest locations of the motor and directing the cooling air across these hot spots, motor fan assembly  70  is more efficiently cooled, thus requiring less airflow thereacross. Inlet opening  72  may be a single opening, a number of openings, or may be constructed of plurality of perforations. As shown in FIG. 5, inlet opening  72  may extend radially along the front face  56  of housing  34  to cover a large radial section of the housing  34 . Referring to FIGS. 5 and 6, stepped portion  65  of the exhaust end  59  of the motor housing has its exhaust openings  58  sealed to prevent air flow therethrough. The exhaust openings formed in collar  63  remain open requiring all of the cooling air exhaust to flow between the ribs  64  of the collar. 
     Referring now to FIG. 11, a duct  80  is rigidly mounted on main body  6  and fluidly connects to exhaust end  59  of the housing  34  to capture the cooling air exhaust as the cooling air passes through exhaust openings  58 . It will be appreciated that duct  80  may be of any shape limited to an extent by the interior of the main body  6  and the housing  34 . As shown in FIG. 9, duct  80  includes a sleeve or hood  82  having a hollow radial end portion  84  shaped to matingly engage exhaust end  59  of housing  34  (FIG.  9 ). Particularly, sleeve  82  is provided with an opening  86  sized to rotatably receive the stepped portion  65  housing exhaust end  59 , as shown in FIG. 9 . Opening  86  allows sleeve  82  to fit snugly over stepped portion  65  for providing fluid communication between exhaust openings  58  and duct  80 . Sleeve  82  includes an inner edge  88  (FIG. 12) which abuts the end of housing  34  to substantially seal the fluid connection between the duct  80  and the exhaust openings  58 . The abutting contact between the inner edge  88  of sleeve  82  and the rotatable non-rigid engagement between opening  86  and stepped portion  65  allow motor fan assembly  70  to rotate relative to main body  6  when upper housing  22  pivots during use of vacuum cleaner  5 . Thus, sleeve  82  allows the motor fan assembly to rotate with the upper housing while maintaining constant fluid communication between the exhaust openings and duct  80  allowing duct  80  to continuously capture the carbon dust laden cooling air. 
     Referring to FIGS. 9,  11  and  12 , the hollow interior of sleeve  82  communicates with a transverse portion  90  of the duct  80  which extends within main body  6  generally perpendicular to sleeve  82 . Transverse portion  90  of duct  80  includes a distal end  92  which communicates with an opening  94  (FIGS. 12 and 13) formed in an inner side wall  96  of dirt duct  10 . As shown in FIGS. 12 and 13, the opening  94  allows the cooling air exhaust (indicated by arrows B) flowing through duct  80  to be combined with the working air and blown into the filter bag  24  by working fan  45 , as described above. By combining the carbon dust laden cooling air with the working air the carbon particles can be separated from the air flow by the filter bag  24  thus providing cleaner overall emissions from the vacuum cleaner  5 . It is understood that duct  80  may be a separate member, as shown in FIGS. 9 and 11 or may be integrally molded with main body  6  (FIG.  12 ). Sleeve  82  provides for a continuous sealed relationship between the stationary duct  80  and the motor housing  34  yet allows rotational movement of motor fan assembly  70  relative to main body  6 . 
     It is well known that electric motors discharge ozone gas. This ozone gas which is discharged from motor  35  combines with the carbon dust laden cooling air and is blown out of motor housing  34  through exhaust openings  58 . As described above, duct  80  captures the exhaust air from motor fan assembly  70 , and thus the ozone gas, and directs the combined cooling air exhaust and ozone gas into filter bag  24 . It is also well known in the art that ozone gas acts as an odor neutralizer which, when blown into the filter bag  24 , will assist in killing bacteria and neutralizing odors which are emitted by the dust, dirt and debris picked up by vacuum cleaner  5 . 
     Duct  80  is shown in FIGS. 9 and 11 as an integrally formed one-piece member but it is understood that duct  80  may also be formed of several pieces without affecting the concept of the invention. Such a several piece duct is shown in FIG.  10  and is indicated generally at  100 . Duct  100  includes a sleeve  102  substantially similar to sleeve  82  of duct  80  and includes a nipple  104  extending outwardly perpendicular to the front end of sleeve  102 . A flexible tube or hose  106  engages nipple  104  and extends transversely across main body  6 . Flexible tube  106  may be formed of any suitable flexible hose or tubing, such as a corrugated tubing or a smooth rubber or plastic hose. A connector  108  having a nipple  110  and a rigid flange  112  attaches to the end of tube  106  opposite sleeve  102 . Flange  112  may be slidably received within a groove (not shown) formed on each side of opening  94  for attaching the end of duct  100  to the wall of dirt duct  10 . 
     The ducts  80  and  100  may be otherwise placed in communication with the working air inlet  50  such that, as shown in FIG. 11, the cooling air is directed into the working airstream. In this way, the cooling air exhausted from the motor is blown into the filter bag  24  by the motor fan assembly  70 . Any particulate such as carbon from the commutator brushes may be trapped within the filter bag  24  preventing these particles from entering the atmosphere. Further, ozone produced by the motor  35  may be directed into the working airstream killing bacteria entrained in the working air. 
     First and second ducts  80  and  100  which fit around stepped portion  65  of housing  34  permit rotational movement of the motor housing  34  while maintaining communication between the cooling air outlet  58  and the dirt duct  10 . An opening  94  may be formed in the dirt duct  10  to establish communication between the dirt duct and transverse portion  90  and hose  106 . In either embodiment, the ducts  80  and  100  are stationary on the main body  6  of vacuum cleaner  5 . With the duct fixed, the step portion  65  of motor housing  34  rotates within the duct when the handle  28  is pivoted during use of vacuum cleaner  5 . Since the cooling outlet  58  is covered by the ducts  80  and  100 , the ducts maintains fluid communication with the outlet  58  throughout rotation. To ensure that the ducts do not occlude the cooling air inlet  55 , the transversely extending portions of the ducts may be spaced radially outward from the motor housing  34  to provide a gap through which air can reach the cooling inlet  55 . Alternatively, the cooling air inlet may be provided with a cover for directing air peripherally along the surface of motor housing  45  and preventing the transverse portion of the ducts from contacting the cooling inlet  55 . By determining the hotspots of the motor  35  the cooling air can be directed to these hotspots for providing a more efficient cooling of motor  35 . As shown in FIG. 11, the cooling air inlet  55  is formed radially in the front face  56  of the motor housing  34  at a location overlying the commuator  37  and carbon brushes  39 . 
     As shown in FIGS. 7 and 8, motor fan assembly  70  may also include cooling air inlets  114  which are formed substantially around the circumference of motor housing  34 . A rounded hood  116  may protrude outwardly from the curved side walls of motor housing  34  forming a channel  118  therebetween. By forming cooling air inlets  114  substantially around the circumference of the motor housing, the cooling air can be more effectively directed about the commutator, amature and field windings thus resulting in more effective cooling of motor  35 . 
     In an alternative embodiment, depicted in FIGS. 14-18 the cooling air is directed into the working air by so called “reverse flow.” A motor fan assembly  120  which is similar to motor fan assembly  70  described above includes a housing  134  enclosing a motor  135  (FIG. 16) having a field coil  136 , a commutator  137 , carbon brushes  139  and a shaft  142 . A working fan  145  having blades  146  is coupled to shaft  142  and separated from motor  135  by a wall  147 . The wall  147  and housing  134  substantially define a working air chamber  149  having a working air inlet  150  formed therein. Working air inlet  150  is in communication with the nozzle opening  7  such that the fan  145  draws a dirt laden stream of working air into the working air chamber  149 , represented by arrows A, FIG.  16 . As discussed in the previous embodiment, the working airstream is blown from the chamber  149  to filter bag  24 . 
     As shown in FIGS. 14 and 15, the cooling air inlets formed in the front face of the motor housing are sealed as are the openings formed in stepped portion  65  of the motor housing  134 . An end  159  of the motor housing, which functioned as the exhaust end of motor fan assembly  70  now functions as the cooling air inlet end of motor fan assembly  120 . An opening  158  which functioned as the exhaust openings of motor fan assembly  70  now functions as the cooling air inlet of motor fan assembly  120 . The opening or cooling air inlet  158  may be a single opening, a plurality of openings, or a series of perforations  156  formed in housing  134 . A lint screen (not shown) may be placed near the inlet  158  such that it filters incoming particulate and prevents the particulate from entering the motor. 
     Referring back to FIG. 16, a cooling fan  152  is found within the motor chamber of housing  134  and coupled to shaft  142 . The cooling fan  152  includes blades  153  formed to draw cooling air into the motor chamber (arrows C) directing the cooling airstream across the motor  135 . Alternatively, a conventional exhaust cooling fan may be operated in reverse to draw air into the housing  134 . Referring to FIG. 17, a plurality of holes  160  are formed in wall  147 . Referring to FIG. 18, a plurality of holes  162  are formed in working fan  145 . Holes  160  and  162  allow the cooling airstream C to enter the working fan chamber  149  (FIG.  14 ), where it can be combined with the working airstream (arrows A), flow out of the motor housing  134 , as indicated by arrows D, and into the filter bag  24 . As will be appreciated holes  160  of the wall  147  may be located at a position on wall  147  including near the perimeter, near the shaft  142 , or in an intermediate location as shown. The holes  160  may further be spaced to distribute the flow around the motor  135 . As with holes  160 , holes  162  of working fan  145  may be located anywhere on fan  145 . As shown in FIG. 16, holes  162  may be placed between blades  146  and located near the central axis of fan  145  or near shaft  142 . As best shown in FIG. 18, the cooling airstream passes through holes  160  and  162  and is directed toward the filter bag  24  by the rotation of fan  145  as indicated by arrows D. 
     In this embodiment, the cooling air is drawn over substantially the entire exterior surface of the motor  135  resulting in more efficient cooling of the motor  135 . The cooling air is then directed into the filter bag  24  by working fan  145  capturing any waste produced by the motor  135  in the filter bag. For example, the carbon particulate given off by a motor having commutator brushes may be collected in filter bag  24 . Also, ozone produced by the motor  135  is combined with the working airstream where it may kill entrained bacteria. 
     Thus it can be seen that at least one of the objects of the invention have been satisfied by the structure presented hereinabove. While in accordance with the patent statutes, the best mode of the invention has been presented and described in detail, the invention is not limited thereto or thereby. Accordingly, for an appreciation of the true scope and breadth of the invention, reference should be made to the following claims.