Abstract:
A floor cleaning apparatus includes a nozzle assembly and a canister assembly. A suction generator is carried on the nozzle assembly or the canister assembly. A dirt collection vessel is also carried on the nozzle assembly or the canister assembly. Still further, a first agitator with a first internal drive motor and a second agitator with a second internal drive motor are both carried on the nozzle assembly. Additionally, a method is also provided. The method includes the steps of equipping a floor cleaning apparatus with first and second agitators and independently driving those agitators.

Description:
[0001]     This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/539,467 filed on Jan. 27, 2004. 
     
    
     TECHNICAL FIELD  
       [0002]     The present invention relates generally to the vacuum cleaner art and, more particularly, to a vacuum cleaner incorporating twin agitators with each agitator driven by an internal drive motor.  
       BACKGROUND OF THE INVENTION  
       [0003]     A vacuum cleaner is an electromechanical appliance utilized to effect the dry removal of dust, dirt and other small debris from carpets, rugs, fabrics or other surfaces in both domestic and industrial environments. In order to achieve the desired dirt and dust removal, a rotary agitator is provided to beat dirt and dust from the nap of the carpet and a pressure drop or vacuum is used to force air entrained with this dirt and dust into the nozzle of the vacuum cleaner. The particulate-laden air is then drawn through a bag-like filter, a dirt cup or a cyclonic separation chamber and filter combination which traps the dirt and dust, while substantially clean air is exhausted by an electrically operated fan that is driven by an on board motor. It is this fan and motor arrangement that generates the drop in air pressure necessary to provide the desired cleaning action. Thus, the fan and motor arrangement is commonly known as the vacuum or suction generator.  
         [0004]     Many advanced, high performance vacuum cleaners incorporate a dual motor system. In such a system, a separate agitator drive motor is provided in addition to the motor of the suction generator. In most designs the separate agitator drive motor is mounted on the nozzle assembly adjacent the agitator. A gear drive or more commonly a pulley and belt arrangement transmits the power from the agitator motor drive shaft to the agitator.  
         [0005]     While very effective for its intended purpose, the mounting of a separate agitator drive motor in front of or behind the agitator necessitates a significant increase in the fore-aft length of the nozzle assembly in order to accommodate the motor. This not only increases the overall weight of the nozzle assembly but also the wheelbase and/or the body overhang beyond the wheels. All of these characteristics negatively impact the ease of manipulation of the vacuum cleaner in and around furniture and, therefore, are a detriment.  
         [0006]     In contrast, it is possible to mount the agitator drive motor above the agitator. In this situation, no increase in the length of the nozzle assembly and/or the wheelbase thereof is necessary to accommodate the agitator motor. The height of the nozzle assembly must, however, be increased significantly to provide motor clearance. This unacceptably restricts the use of the vacuum cleaner as the resulting higher profile will not clear many overhanging obstructions such as bed frames, tables and chair frames. Accordingly, this is generally recognized to be an unacceptable solution.  
         [0007]     Another possible alternative is the mounting of the separate agitator drive motor within the agitator itself. Such an arrangement makes use of what would otherwise be lost space within the agitator. Further, it allows the agitator motor to be accommodated without any substantial increase in the height or length of the nozzle assembly. Thus, the vacuum cleaner may be more easily manipulated on a shorter wheel base and is of lighter overall weight. It also includes the desired low profile which allows cleaning under bed frames, tables, chairs and other such objects.  
         [0008]     More recently, it has been determined that vacuum cleaners equipped with multiple agitators provide a performance advantage resulting in enhanced cleaning efficiency. The present invention relates to a multi-agitator vacuum cleaner wherein each agitator is independently driven and includes its own internally mounted drive motor. Such a vacuum cleaner provides maximum cleaning performance while also limiting the height and footprint of the nozzle assembly. As a consequence, the vacuum cleaner is easy to maneuver and has a relatively low profile so as to allow cleaning under beds, chairs and the like.  
       SUMMARY OF THE INVENTION  
       [0009]     In accordance with the purposes of the present invention as described herein, an improved floor cleaning apparatus is provided. That floor cleaning apparatus comprises a nozzle assembly, a canister assembly and a suction generator carried on one of the nozzle assembly and the canister assembly. Additionally, the floor cleaning apparatus includes a dirt collection vessel also carried on one of the canister assembly and the nozzle assembly. Still further, a first agitator having a first internal drive motor is carried on the nozzle assembly. Additionally, a second agitator having a second internal drive motor is carried on the nozzle assembly.  
         [0010]     The canister assembly may be pivotally connected to the nozzle assembly. Further, the dirt collection vessel may take any of various forms including but not limited to a filter bag, a dirt cup and a cyclonic airflow chamber. Further, the cleaning apparatus itself may be a device selected from a group consisting of an upright vacuum cleaner, a canister vacuum cleaner, a hand-held vacuum cleaner and an extractor.  
         [0011]     Alternatively, the present invention may be described as a floor care cleaning apparatus comprising a nozzle assembly, a canister assembly, a suction generator carried on one of the nozzle assembly or the canister assembly and a dirt collection vessel carried on one of the nozzle or the canister assembly. The apparatus further includes a first agitator and first agitator drive motor and a second agitator and second agitator drive motor. Thus, the two agitators are independently powered.  
         [0012]     In accordance with yet another aspect of the present invention, a method is disclosed for providing an improved floor cleaning apparatus. The method includes the steps of equipping the floor cleaning apparatus with a first agitator and a second agitator and independently driving those two agitators. The agitators may be driven at different speeds and/or in different directions.  
         [0013]     Advantageously, the floor cleaning apparatus provides enhanced cleaning performance and a relatively low profile and compact nozzle assembly that is easily maneuvered over a surface to be cleaned and has the necessary clearance to be used under beds, chairs and the like.  
         [0014]     In the following description there is shown and described a preferred embodiment of this invention, simply by way of illustration of one of the modes best suited to carry out the invention. As it will be realized, the invention is capable of other different embodiments and its several details are capable of modification in various, obvious aspects all without departing from the invention. Accordingly, the drawings and descriptions will be regarded as illustrative in nature and not as restrictive. 
     
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0015]     The accompanying drawing incorporated in and forming a part of the specification, illustrates several aspects of the present invention, and together with the description serves to explain certain principles of the invention. In the drawing:  
         [0016]      FIG. 1  is a perspective view of a floor cleaning apparatus of the present invention, illustrated in the form of an upright vacuum cleaner;  
         [0017]      FIG. 2  is a transverse sectional view of the vacuum cleaner through the first agitator; and  
         [0018]      FIG. 3  is a detailed cross-sectional view of the first agitator and gear drive showing the engagement therebetween. 
     
    
       [0019]     Reference will now be made in detail to the present preferred embodiment of the invention, an example of which is illustrated in the accompanying drawing.  
       DETAILED DESCRIPTION OF THE INVENTION  
       [0020]     Reference is now made to  FIG. 1  showing a floor cleaning apparatus  10  of the present invention. As illustrated, that floor cleaning apparatus  10  takes the form of an upright vacuum cleaner. It should be appreciated, however, that the floor cleaning apparatus may also take the form of a canister vacuum cleaner, a hand-held vacuum cleaner or even an extractor.  
         [0021]     The overall basic design of the floor cleaning apparatus  10  is generally well known in the art. In the typical arrangement, the floor cleaning apparatus  10  includes a housing  14  that comprises the nozzle assembly  16  and the canister assembly  18 . The canister assembly  18  further includes the handle  20  and the hand grip  22 . The hand grip  22  carries a control switch  24  for turning the floor cleaning apparatus  10  on and off. Of course, electrical power is supplied to the floor cleaning apparatus  10  from a standard electrical wall outlet through a cord (not shown). Alternatively, the floor cleaning apparatus  10  could be powered by an onboard battery.  
         [0022]     At the lower portion of the canister assembly  18 , rear wheels (not shown) are provided to support the weight of the floor cleaning apparatus  10 . A second set of wheels (also not shown) allow the operator to raise and lower the nozzle assembly  16  through selective manipulation of the height adjustment switch  28 . Such a height adjustment mechanism is well known in the art and is exemplified, for example, by the arrangement incorporated into the Kenmore Progressive vacuum cleaner currently available in the marketplace. To allow for convenient storage of the floor cleaning apparatus  10 , a foot latch  30  functions to lock the canister assembly  18  in an upright position, as shown in  FIG. 1 . When the foot latch  30  is released, the canister assembly  18  may be pivoted relative to the nozzle assembly  16  as the floor cleaning apparatus  10  is manipulated to clean the floor.  
         [0023]     The canister assembly  18  also carries an internal chamber  32  that houses a suction generator  33  (i.e. a state of the art fan and motor combination) and a dirt collection vessel  34  for removing dirt or dust entrained in the air stream as it passes from the nozzle assembly  16  to the suction generator. The canister assembly  18  may also carry a final filtration cartridge  48  to trap small particulates and prevent their reintroduction into the environment through the exhaust air stream.  
         [0024]     The nozzle assembly  16  includes a nozzle and agitator cavity  36  that houses multiple rotating agitators  38 . The agitators  38  shown are each independently and rotatably driven by a motor  40  and cooperating gear drive  42  housed within the agitator and described in greater detail below (see  FIGS. 2 and 3 ). In the illustrated floor cleaning apparatus  10 , the scrubbing action of the rotary agitators  38  and the negative air pressure created by the suction generator  33  cooperate to brush and beat dirt and dust from the nap of the carpet being cleaned and then draw the dirt and dust laden air from the agitator cavity  36  to the dirt collection vessel  34 . Specifically, the dirt and dust laden air passes serially through a suction inlet and hose and/or an integrally molded conduit in the nozzle assembly  16  and/or canister assembly  18  as is known in the art. Next, it is delivered into the dirt collection vessel  34  held in the chamber  32 . The vessel  34  serves to trap the suspended dirt, dust and other particles inside while allowing the now clean air to pass freely through the porous wall thereof and then through the suction generator  33 , final filtration cartridge  48  and ultimately to the environment through the exhaust port  50 .  
         [0025]     As illustrated, the dirt collection vessel  34  takes the form of a dust or filter bag of a type well known in the art. Of course, it should be appreciated that the dirt collection vessel could also be a dirt cup or even a cyclonic separation chamber if desired. Essentially substantially any vessel capable of collecting dirt may be utilized.  
         [0026]     Reference is now made to  FIGS. 2 and 3  which show the mounting of the agitator motor  40  and associated gear drive  42  in one of the agitators  38  in detail. As shown, the agitator  38  is mounted for rotation relative to the nozzle assembly  16 . Specifically, a first end of the agitator  38  includes an end cap  52  which is supported on bearings  54  on a stub shaft  55  held in mounting block  56  keyed into slot  58  in the side of the nozzle assembly  16 . An end cap  60  at the opposite end of the agitator  38  is supported on bearings  62  mounted on the housing  64  of the motor  40 . As should be appreciated, the motor  40  is fixed to the nozzle assembly  16  by means of the mounting block  66  fixed to the motor housing  64  and keyed in the slot  68  in the side of the nozzle assembly.  
         [0027]     The motor  40  drives a shaft  70  including gear teeth  72 . The drive shaft  70  extends through a bearing  74  held in the hub  76  of the planetary gear set carrier  78 . In the most preferred embodiment a fan  80  is keyed or otherwise secured to the distal end of the drive shaft  70 .  
         [0028]     The planetary gear set carrier  78  includes three stub shafts  82  that each carry a planetary gear  84 . Each of the planetary gears  84  include teeth that mesh with the gear teeth  72  of the drive shaft  70 . Additionally, the planetary gears  82  mesh with the teeth of an annular gear  86  that is fixed to the agitator motor housing  64  by pin or other means. Thus, it should be appreciated that as the drive shaft  70  is driven by the motor  40 , the planetary gears  84  are driven around the annular gear  86 , thereby causing the planetary gear set carrier  78  to rotate. Planetary gear set carrier  78  also includes a drive ring  88  and associated rubber drive boot  87  which includes a series of spaced channels  89  that receive and engage axial ribs  91  projecting inwardly radially from the inner wall of the agitator  38 . Thus, the rotation of the planetary gear set carrier  78  is transmitted by the drive ring  88  and drive boot  87  directly to and causes like rotation of the agitator  38 . The rubber drive boot  87  provides the necessary damping to insure the smooth transmission of power to the agitator. Simultaneously with the rotation of the planetary gear set carrier  78  and agitator  38 , the drive shaft  70  also drives the fan  80  at a ratio of between 4-1 to 10-1 (e.g. 6-1) with respect to the agitator  38 . The resulting rapid rotation of the fan  80  helps to ensure proper cooling of the agitator motor  40  during its operation.  
         [0029]     More specifically, the floor cleaning apparatus  10  of the present invention incorporates a novel air cooling system or circuit, which will now be described in detail. Specifically, air is drawn into the floor cleaning apparatus  10  through a vent  90  at the upper rear face of the nozzle assembly  16  by operation of the suction generator  33  (note action arrow A in  FIG. 2 ). Specifically, the air first passes through a filter (not shown) of foam rubber or other appropriate material into the illumination compartment  94  defined between the upper transparent window  96  and the lower transparent window  98  which allow viewing of the operation of the agitator  38 . This air then passes over and around the light source  100  so as to provide cooling thereto (note action arrows B in  FIG. 2 ). Next, the air is drawn through the passageway  102  in the nozzle assembly  16  and around and through an opening  104  in the end cap  52  (note action arrow C). The air then moves through the lumen of the agitator  38  to the fan  80  driven by means of the agitator drive motor  40  (note action arrows D). The fan  80  forces the air through openings  106  in the planetary gear set carrier  78  (see also  FIG. 3 ) and then around the annular gear  86  before it passes through the housing  64  of the motor  40  (note action arrows E and F).  
         [0030]     After passing over the windings and other internal components (not shown) of the agitator motor  40  for purposes of heat exchange and cooling, the air passes through the passageway  108  into the manifold  110  (note action arrow G). Manifold  110  includes an outlet (not shown) in fluid communication with the agitator cavity  36 . Of course, as noted above, the agitator cavity  36  is in direct fluid communication with a suction inlet  44  that leads through the hose  46  into the dirt collection vessel  34  in chamber  32 .  
         [0031]     While only one agitator  38  has been illustrated and described in detail, it should be appreciated that both agitators  38  have identical structures: that is, each agitator  38  has its own drive motor. As a result, the agitators  38  are independently driven. The agitators  38  may be driven by their individual, independent internal motors in different directions and/or even at different speeds as desired to provide the greatest cleaning efficiency. Thus, design flexibility and performance are all maximized.  
         [0032]     The foregoing description of a preferred embodiment of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. For example, while two agitators are illustrated, it should be appreciated that three or even more could be provided.  
         [0033]     The embodiment was chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally and equitably entitled.