Patent Publication Number: US-7213298-B2

Title: Clutchless self-propelled vacuum cleaner and nozzle height adjustment mechanism therefor

Description:
BACKGROUND OF THE INVENTION 
   This application is a divisional application of U.S. patent application Ser. No. 10/339,191 which was filed on Jan. 9, 2003 and is still pending. 

   The present invention relates to vacuum cleaners. More specifically, the invention relates to self-propelled vacuum cleaners. 
   Known self-propelled vacuum cleaners include an electric motor disposed in a nozzle base of the cleaner for driving a set of driven wheels. The drive motor, via a clutch, exerts a driving force on the driven wheels in the direction of movement desired by the operator. Some operators value self-propelled vacuum cleaners because they are easier to move from place to place while vacuuming a room. 
   In the prior art self-propelled vacuum cleaners, a clutch mechanism is provided to allow the motor, which normally rotates only in a single direction, to drive the vacuum cleaner in both a forward and a reversed direction. It is apparent that clutches add to the complexity of the vacuum cleaner power drive system. Accordingly, it would be desirable to have a clutchless direct drive type vacuum cleaner. 
   As is well known, vacuum cleaners also include height adjustment mechanisms to enable the vacuum cleaner to be employed on carpeting of various heights or on bare floors. Conventionally, the nozzle base had to include both drive wheels for the power drive mechanism and separate rollers or wheels which were coupled to the nozzle height adjustment mechanism of the vacuum cleaner. Accordingly, it would be desirable to provide a drive mechanism which can also serve as part of a height adjustment mechanism for the vacuum cleaner in order to reduce the number of parts in the nozzle base, thereby reducing both the complexity and the cost of manufacture of the nozzle base. 
   SUMMARY OF THE INVENTION 
   According to the present invention, a new and improved self-propelled vacuum cleaner is provided. More particularly, in accordance with one aspect of the invention, a clutchless direct drive, self-propelled vacuum cleaner comprises a nozzle base having a suction inlet and a housing pivotally mounted on the nozzle base. A suction source is mounted to one of the nozzle base and the housing. A filter chamber is located in one of the nozzle base and the housing. A drive motor is mounted to one of the nozzle base and the housing, the drive motor having an output shaft. A transmission is directly coupled to the output shaft of the motor and a driven wheel is directly coupled to the transmission. 
   In accordance with another aspect of the invention, a direct drive self-propelled vacuum cleaner is provided. More particularly, in accordance with this aspect of the invention, a nozzle base having a suction inlet is provided and a housing is pivotally mounted on the nozzle base. A suction source is mounted to one of the nozzle base and the housing. A filter chamber is located in one of the nozzle base and the housing. A drive motor is mounted to one of the nozzle base and the housing with the drive motor having an output shaft. A control is located in one of the housing and the nozzle base for directing a rotational direction and speed of the drive motor. A transmission is directly coupled to the output shaft of the drive motor. A driven wheel is directly coupled to the transmission. 
   In accordance with still another aspect of the invention, a height adjustment mechanism is provided for a self-propelled vacuum cleaner. The height adjustment mechanism comprises a nozzle base having a suction inlet, an upright housing pivotally mounted to the nozzle base and a suction source mounted to one of the nozzle base and the upright housing. A filter chamber is located in one of the nozzle base and the upright housing. A drive motor is mounted on a motor housing pivotally connected to the nozzle base. A driven wheel is connected to the drive motor. A height adjustment control is mounted to the nozzle base and a cam is connected to the height adjustment control. A height adjustment lifter is pivotally mounted to the nozzle base and cooperates with the cam. The height adjustment lifter contacts the motor housing to rotate same and thus adjust a height of the suction inlet in relation to an associated subjacent support surface. 
   In accordance with yet another aspect of the present invention, a height adjustment mechanism is provided for a self-propelled vacuum cleaner. More particularly, in accordance with this aspect of the invention, a nozzle base having a suction inlet is provided. At least one wheel is rotatably mounted to the nozzle base for supporting the nozzle base on an associated subjacent support surface. A housing is connected to the nozzle base and a suction source is mounted to one of the nozzle base and the housing. A filter chamber is located in one of the nozzle base and the housing. A drive motor is mounted to the nozzle base, the drive motor having an output shaft. A driven wheel is coupled to the drive motor output shaft. A height adjustment control is mounted to the nozzle base and a cam is connected to the height adjustment control. A height adjustment lifter is pivotally mounted to the nozzle base and cooperates with the cam, wherein the height adjustment lifter contacts the motor housing to rotate same and thus adjust a height of the suction inlet in relation to the associated surface. 
   The advantages and benefits of the present invention will become apparent to those of ordinary skill in the art upon a reading and understanding of the following detailed description of the preferred embodiment. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The drawings are only for purposes of illustrating a preferred embodiment of the present invention and are not to be construed as limiting same. The invention may take form in various components and arrangements of components and in various steps and arrangements of steps, a preferred embodiment of which will be illustrated in the accompanying drawings and wherein: 
       FIG. 1  is a perspective view illustrating a self-propelled upright vacuum cleaner in accordance with the present invention; 
       FIG. 2  is an enlarged exploded perspective view of an upper portion of the vacuum cleaner including a handle assembly; 
       FIG. 3  is an assembled side elevational view, in cross-section, of a handle assembly of  FIG. 2 ; 
       FIG. 4  is a side elevational view of the handle assembly of  FIG. 3 ; 
       FIG. 5  is an enlarged exploded perspective view of a base assembly of the vacuum cleaner of  FIG. 1 ; 
       FIG. 6  is an enlarged exploded perspective view of a drive motor and transmission assembly of the vacuum cleaner of  FIG. 1 ; 
       FIG. 7  is an enlarged side elevational view of the nozzle base of  FIG. 1 , in section, illustrating the drive wheels of a power drive assembly of the vacuum cleaner in an up position and a nozzle adjacent a floor surface; 
       FIG. 8  is an enlarged side elevational view of the nozzle base of  FIG. 1  illustrating the drive wheels of the power drive mechanism in a down position and the nozzle spaced from the floor surface; 
       FIG. 9  is an enlarged side elevational view of the nozzle base of  FIG. 8  along another section; 
       FIG. 10  is a reduced perspective view of the nozzle base of  FIG. 9 ; 
       FIG. 11  is an enlarged exploded perspective view of various height adjustment components and controls of the vacuum cleaner of  FIG. 10 ; and, 
       FIG. 12  is a developed view of a side wall of a nozzle height adjusting knob of the vacuum cleaner of  FIG. 11  illustrating a cam surface thereof. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring now to the figures wherein the showings are for purposes of illustrating a preferred embodiment of the present invention and not for purposes of limiting same,  FIG. 1  illustrates a self-propelled upright vacuum cleaner  10 . The upright vacuum cleaner includes a nozzle base  12  having a suction inlet  14 . An upright housing  16  is pivotally mounted on the base  12 . A suction source  18 , which conventionally includes a motor fan assembly is disposed in one of the base  12  and the upright housing  16 . As best shown in  FIG. 9 , the motor is mounted in a lower portion of the upright housing  16 . 
   A filter chamber  20  is mounted to one of the base and the upright housing. The suction source communicates the suction inlet  14 , through conduits, such as the hose illustrated at  21 , with the filter chamber  20 , as is well known in the art. The filter chamber  20  and its communication with the suction inlet is discussed in greater detail in application Ser. No. 10/224,483 which was filed on Aug. 20, 2002 and is entitled “Vacuum Cleaner Having Hose Detachable at Nozzle”. That application is incorporated herein by reference in its entirety. In order to allow a user to maneuver the vacuum cleaner, a handle assembly  22  is mounted to the upright housing  20 . Also, a pair of rear wheels  24  (see  FIG. 5 ) support the base  12  above the surface meant to be cleaned in order to facilitate movement of the vacuum cleaner across the surface. 
   With reference now to  FIG. 5 , the vacuum cleaner  10  includes a drive assembly  25  including a drive motor  26  operatively connected to driven wheels  28  and  30  such that the drive motor drives the wheels to propel the base. With reference again to  FIG. 1 , an operator of the vacuum cleaner can control the speed and direction of rotation of the wheels  28  and  30  by manipulating the handle assembly  22 . The drive motor  26  is in communication via circuitry (not shown) with a sensor assembly, which will be described in more detail below, located in the handle assembly  22 . As the operator manipulates the handle assembly  22 , the drive motor  26  reacts to propel the base accordingly. 
   With reference now to  FIG. 2 , the handle assembly  22  includes an upper handle  40 , a handle grip assembly  42 , a neutral return spring  44  and a sensor assembly  46  that communicates through known electrical circuitry (not shown) to control the speed and direction of rotation of the motor  26 . Additional description of the handle assembly, the neutral return spring and the sensor assembly is found in a patent application entitled “Self-propelled Vacuum Cleaner With Neutral Return Spring”, Ser. No. 10/339,749, filed on Jan. 9, 2003. The subject matter of that application is incorporated by reference hereinto in its entirety. 
   Briefly, a switch trigger  74  on the handle grip assembly  42  is employed to selectively actuate the drive motor  26 . The switch trigger actuates a switch  104  which is electrically connected via circuitry (not shown) to a power cord (not shown) that can connect to an external power source. The power source supplies power to the suction source  18  and to the drive motor  26 . To activate the switch  104 , and thus to power the drive motor  26 , the operator depresses the trigger  74  as depicted by arrow A in  FIG. 3 . Letting go of the trigger  74  will deactivate the drive motor  26 . A separate switch (not visible in  FIG. 1 ) is used to selectively power the suction source  18 . As described in the copending application referenced above, the sensor assembly  46  can include a Hall effect probe  170  and a pair of spaced magnets  174  and  176 . The neutral return spring has inherent damping characteristics to reduce the possibility of directing the motor to quickly change from a forward rotation to a backward rotation, and back again, instead of simply stopping its rotation when a pulling or pushing force, indicated by arrow Y in  FIG. 4 , on the hand grip assembly  42  is stopped by the operator. 
   As mentioned, the operator manipulates the handle assembly  22  to control the direction and speed of rotation of the drive motor  26 . To this end, and with reference again to  FIG. 5 , the drive motor  26  can be a brushless DC reversible motor. Accordingly, a rectifier (not shown) is positioned somewhere in the electronic circuitry to convert AC power of an external power source to DC power for the motor. Of course, it should be recognized that an AC motor could be provided as well, thus obviating the need for a rectifier. The motor  26  drives a transmission  232  which in turn drives the wheels  28  and  30 . The motor  26  is illustrated to be a direct drive motor, thus, eliminating the need for a clutch in the transmission to reverse the direction of rotation of the transmission and the driven wheels  28 ,  30 . 
   With reference now to  FIG. 6 , the transmission  232  includes a pinion gear  234  driven by an output shaft  236  of the motor  26 . The output shaft  236  is received in an opening  238  in the pinion gear  234 . The pinion gear drives a first gear  242  which includes a toothed extension  244 . The extension  244  intermeshes with and drives an intermediate gear  246 , that also includes an extension  248 . Intermeshing with the extension  248  is a sprocket  252  driven thereby. The first gear  242  and the extension  244  include an opening  254  to receive a first gear shaft  256 . The intermediate gear  246  and the extension  248  include an opening  258  to receive a second gear shaft  262 . A gear spacer  260  is positioned between the first gear  242  and its housing. 
   The sprocket  252  includes an opening  264  having a keyed notch  266 . Received in the opening  264  is an axle  268 . The axle  268  includes a bore  272  to receive a pin  274 . The pin  274  is received in the keyed notch  266  to lock the axle  268  to the sprocket  252 . Accordingly, as the sprocket  252  rotates, it turns the axle  268 . Mounted on the axle  268  are the driven wheels  28  and  30 . Although a specific type of transmission has been described herein, it should be apparent to one of ordinary skill in the art that the invention encompasses many different types of transmissions. 
   Included on the axle  268  is a first squared end  276  that is received in an opening (not shown) in the first wheel  28  and a second squared end  278  that is received in an axle opening in the second wheel  30 . A bearing  282 , a curved washer  284  and a flat washer  286  are received on the axle  268 . A wheel lock  288  and a retainer ring  292  are received on the squared end  276  to fasten the wheel  28  to the axle. A similar mounting arrangement is provided for the wheel  30 . Although a specific type of connection between the wheels  28  and  30  and the axle  268  has been disclosed, it should be apparent that the invention encompasses any type of connection between axles and wheels that is generally known in the art. 
   Enclosing the transmission  232  is a transmission housing  302  ( FIG. 5 ). The transmission housing  302  includes a first half  304  and a second half  306  of a clam shell type housing. The first half  304  includes a well  308  to receive the motor  26 . The well abuts a wall  312  of the first clam shell half on one end. Protruding through an opening  314  in the wall  312  is the output shaft  236  of the motor  26 . The first half  304  of the housing also includes an axle housing  316  which comprises a hollow cylindrical portion that receives the axle  268 . A motor cover  318  mounts over the well  308  to secure the motor  26  in place when it is positioned in the well. 
   The second clam shell housing half  306  also includes an axle housing  320  to receive the axle  268 . Included in the second half  306  is a first shaft opening  322  to receive the gear shaft  256  of the first gear  242  and an intermediate shaft opening  324  to receive the gear shaft  262  of the intermediate gear  246 . Further, the second half also includes openings  326  that align with openings  328  on the first half  304  to receive conventional fasteners  330  for attaching the first housing half to the second housing half. 
   With reference now briefly to  FIG. 8 , the base  12  includes a cavity  334  to house a brushroll  336 . As shown in  FIG. 5 , a circuit board  342  is mounted to the base  12  and is electronically connected to the sensor assembly  46  described above. The sensor assembly  46 , which could also be termed a detector assembly, delivers a signal to the circuit board  342  which translates the signal to control the direction of rotation and speed of the motor  26 . The circuit board  342  can include various circuits to treat the electrical signal sent to the motor  26  and other controls for the motor. Such circuits and controls are disclosed in copending applications entitled “Control Circuitry for Enabling Drive System For Vacuum Cleaner”, Ser. No. 10/339,097, filed on Jan. 9, 2003 and “Electronically Commutated Drive System For A Vacuum Cleaner”, Ser. No. 10/339,122, filed on Jan. 9, 2003. The subject matter of these two applications is incorporated hereinto by reference in their entireties. 
   With reference now to  FIG. 9 , also provided on a nozzle base  12  is at least one roller  343  which is mounted in a roller well  344  defined on a bottom face  345  of the housing  12 . A roller axle  346  pivotally mounts the roller. It is apparent from  FIG. 9  that the roller is located behind the brushroll  336  but in front of the drive wheels  28  and  30 . Two such rollers can, if desired, be located on the nozzle base bottom face  345 . The rollers are meant to support the nozzle base adjacent its nozzle opening  14  so as to prevent the nozzle opening from approaching a subjacent surface  347  too closely. 
   With reference now to  FIG. 10 , a height adjustment control  350  includes a top wall  352  extending from which is a knob  354 . Also provided is a side wall  356 . With reference now also to  FIG. 12 , defined in the side wall is a cam surface  358 . The cam surface includes first through fifth sections  360 – 366 , which are of different heights. 
   With reference now to  FIG. 11 , cooperating with the height adjustment control  350  is a height adjustment lifter  370  which includes a first end  372 . Defined in a first end, on opposed sides thereof, are stubs  374 . A central portion  376  of the lifter has a reversed D-shaped opening  378 . A first projection  380  extends from a first face  381  of the lifter  370 . A contact surface  382  is provided on a distal end of the projection  380 . As also shown in  FIG. 7 , a second projection  390  extends from a second surface  391  of the lifter. The second projection includes a contact surface  392 . Positioned opposite the first end  372  is a second end  394  of the lifter. 
   Connecting the lifter to the nozzle base  12  is a lifter clamp  400 . The clamp has an upper surface  402  and a lower surface  404 . Defined in the lower surface are channel sections  406 . The channel sections are meant to accommodate the lifter first end stubs  374  so as to allow a pivoting motion of the lifter first end in the channel sections. Transverse apertures  408  extend through opposed ends of the clamp for accommodating suitable fasteners (not illustrated) in order to secure the clamp in place on a pair of bosses (not visible) extending from an upper surface  412  ( FIG. 10 ) of the nozzle base  12 . 
   With reference again to  FIG. 5 , a stub  422  extends from the upper surface  412 . The stub is suitably shaped and sized so as to fit through the opening  378  in the height adjustment lifter  370 . A suitable fastener (not illustrated) secures the height adjustment control  350  to the stub  422  thereby trapping the height adjustment lifter  370  in place. This is best illustrated in  FIGS. 7 and 8 . A stop  426  is defined on an upper surface  428  of the stub  422  to limit rotation of the control  350 . 
   The drive assembly, including the drive motor  26  and the transmission housing  302  to which the motor is mounted, together with the wheels  28  and  30 , is pivotally mounted on the nozzle base  12 . To this end, the transmission housing includes stubs  430  and  432 , as best shown in  FIG. 6 . The stubs are mounted in respective supports  434  and  436  ( FIG. 5 ) that are secured via fasteners (not shown) to the nozzle base  12 . Thus, the drive assembly can pivot in relation to the nozzle base  12 . 
   In order to bias the power drive assembly (including the motor  26  and the wheels  28  and  30 ) towards the nozzle base, a spring  440  is provided. As best shown in  FIG. 8 , the spring has a first end  442  which extends over a hollow protrusion  444  of the nozzle base  12 . A second end  446  of the spring is connected to the first half  304  of the transmission housing. For this purpose, an ear  450  defined on the first half  304  is provided with an aperture  452  to accommodate the spring second end  446 , as best shown in  FIG. 5 . 
   With reference again to  FIG. 5 , a speed selector switch  502  can be mounted to the nozzle base  12 . The selector switch can control the rotational speed of the motor  26 . Also mounted to the nozzle base is an enable switch  512 . With reference now also to  FIG. 9 , the enable switch  512  has an arm  514  which extends into a recess  520  defined in the upper housing  16 . To this end, when the upper housing is rotated towards a substantially upright position so that it is substantially perpendicular to the subjacent surface  347 , the arm  514  will contact a wall  522  of the recess thereby deactivating the drive motor  26 . As is evident from  FIG. 11 , a housing  530  encloses the enable switch  512  except that, defined in a rearwardly angled and a rear surface  534  upper surface  532  of the housing  530  is a slot  536 . As shown in  FIG. 10 , the arm  514  protrudes through the slot  536 . 
   As the height adjustment control  350  is rotated, various ones of the cam surface sections  360 – 366  come into contact with the contact surface  382  of the first projection  380  of the height adjustment lifter  370 . Since the control  350  is rotatably mounted on the stub  422  of the nozzle base  12 , and the cam surface sections  360 – 366  are disposed at different heights along the side wall  356 , the height adjustment lifter  370  is constrained to pivot up and down in relation to the nozzle base  12 . Such pivoting will cause the second projection contact surface  392  to push on the axle housing  316  of the transmission  232 . The drive assembly  25  is thus rotated downwardly against the bias of spring  440 , as is evident from a comparison of  FIGS. 7 and 8 . When the height adjustment control is again rotated to a lower height setting, both gravity and spring  440  will urge the drive assembly  25  to retract into the nozzle base  12 , thus lowering the suction opening  14  towards the floor surface  347 . Thus, the drive motor  26  serves two purposes, both as a means for propelling the nozzle base and as part of the height adjustment mechanism for the nozzle base. 
   While the motor  26  is illustrated as driving two wheels  28  and  30 , it should be appreciated that the motor could drive only a single wheel or more than two wheels if so desired. Also, while the power drive motor is illustrated as being mounted to the nozzle base, it could, instead, be mounted to a suitably configured upright housing if so desired. In a design where the upright housing carries the rear wheels of the vacuum cleaner, the drive motor could be coupled to the rear wheels or to one or more separate wheels. In such a design, if coupled to the rear wheels, no extra drive wheels would be required. However, the drive mechanism would not then form part of the height adjustment system of the vacuum cleaner. While the preferred embodiment has been described with reference to such terms as “upper”, “lower”, “vertical”, and the like, these terms are used for better understanding of the invention and with respect to the orientation of the vacuum cleaner and the surface to be cleaned. However, these terms are not meant to limit the scope of the invention. 
   The invention has been described with reference to a preferred embodiment. Obviously, modifications and alterations will occur to others upon a reading and understanding of the preceding detailed description. It is intended that the invention be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims and the equivalents thereof.