Abstract:
A suction nozzle unit for a vacuum cleaner unit includes a casing formed with a suction inlet, a pair of front wheels located at the front of the casing, and a pair of rear wheels located at the rear of the casing. The suction nozzle unit also includes a shaft pin for rotatably supporting the front wheels and an arrangement, for moving the casing up and down relative to the shaft pin so as to raise and lower the front end of the casing relative to the surface to be vacuumed. As a result the front end of the unit can be moved up and down as necessary depending, for example, on the depth of pile of a carpet being vacuumed, thereby increasing ability of the unit to travel over the carpet during vacuuming.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a suction nozzle unit for a vacuum cleaner, and more particularly, a suction nozzle unit for a vacuum cleaner having a mechanism for lifting up a front portion of the suction nozzle unit. 
     DESCRIPTION OF RELATED ART 
     The invention can perhaps be best understood by first considering a conventional vacuum cleaner as illustrated in FIGS. 5 to  7 . Referring to FIG. 5, a conventional vacuum cleaner  90  is comprised of a cleaner body  91 , inside of which a suction fan (not shown) and a filter (not shown) are installed, a suction nozzle unit  101  for sucking dust and debris from a surface to be cleaned, and a suction pipe  93  and a connection hose  97 , both of which connect the suction nozzle unit  101  to the cleaner body  91 . 
     The cleaner body  91  is provided with a pair of rollers  92  and the suction nozzle unit  101  is provided with a pair of front wheels  109  and a pair of rear wheels  106 . The roller  92 , the front and rear wheels  109  and  106  respectively enable the cleaner body  91  and the suction nozzle unit  101  to be moved over the surface to be cleaned. A handle  95  for a user is connected between the suction pipe  93  and the connection hose  97 . By grasping the handle  95 , the user can move the suction nozzle unit  101  on the surface to be cleaned. When the suction nozzle unit  101  is moved, dust and debris attached to the surface to be cleaned are sucked into the suction nozzle unit  101  by the suction force from the suction fan (not shown) installed in the cleaner body  91  and then moved into the cleaner body  91  through the suction pipe  93  and the connection hose  97 . 
     Referring to FIGS. 6 and 7, the conventional suction nozzle unit  101  is comprised of a casing  103  defining the outer appearance of the suction nozzle unit  101 , the above mentioned pair of front wheels  109  and pair of rear wheels  106 , for enabling the user to move the suction nozzle unit  101  over the surface to be cleaned, and a connector  107  to which the aforementioned suction pipe  93  is coupled. 
     The casing  103  is comprised of a lower casing  110  and an upper casing  120  coupled to the lower casing  110 . In the front bottom part of the lower casing  110  is formed a suction inlet  111  for sucking dust and debris from the surface to be cleaned. In the back of the suction inlet  111  are located a pair of oppositely disposed, substantially L-shaped partitioning walls  124 . Between side wall portions  124   a  of the partitioning walls  124  is formed a suction duct  113  which serves as a passageway for the dust and debris sucked through the suction inlet  111 . The top of the suction duct - 113  is covered with the duct cover  123 . In the back of the suction duct  113  is positioned a connector receiving part  125 , with which the connector  107  is rotatably coupled. 
     Between a front wall  110   a  and side walls  110   b  of the lower casing  110 , and front wall portions  124   b  of the partitioning walls  124  is formed a brush receiving part  115  in which a brush member  127  for removing the dust and debris from carpet pile or fiber  89  of a carpet  87  is rotatably installed. The brush member  127  is rotated by a brush motor (not shown). 
     In the front and back sides of the lower casing  110  are respectively installed wheel coupling parts  117  with which the front and rear wheels  109  and  106  are coupled. 
     With this configuration, the suction nozzle unit  101  sucks dust and debris from the surface to be cleaned by the suction force generated from the suction fan (not shown) installed in the cleaner body  91  and through the suction inlet  111 . The dust and debris vacuumed or sucked up from the carpet is transported into the cleaner body  91  through the suction duct  113  and the connector  107 . 
     A disadvantage of this kind of a conventional suction nozzle unit  101  is that the height of the bottom face of the lower casing  110  relative to the surface to be cleaned is so small that the suction inlet  111  closely contacts the surface to be cleaned, and therefore, movement of the suction nozzle unit  101  is restricted depending on the shape or nature of the surface to be cleaned. This is a particular problem in cleaning the deep pile carpet  87  depicted in FIG. 7, wherein all or a part of the carpet fibers  89  of the carpet  87  may be directed toward the suction inlet  111  of the lower casing  110 , thereby causing resistance against the movement of the suction nozzle unit  101 . Further, in the case of the deep pile carpet  87 , i.e., a carpet having relatively long carpet fibers as indicated  89 , stronger resistance will be caused against the movement of the suction nozzle unit  101 . For all these reasons, movement of the suction nozzle unit  101  can be difficult when vacuuming deep pile carpets. In addition, the user must exert himself or herself more vigorously to move the suction nozzle unit  101  in order to overcome the resistance against movement exerted on the suction nozzle unit  101 , and as a consequence, the job of vacuuming can become tiring and burdensome. 
     SUMMARY OF THE INVENTION 
     An important object of the present invention is to overcome the above-described problems and, to this end, a suction nozzle unit is provided for a vacuum cleaner which enables easier and more convenient vacuuming by reducing the resistance against the movement of the suction nozzle unit so as to enhance the movability thereof. 
     This object of the present invention is accomplished through the provision of on an improved suction nozzle unit for a vacuum cleaner comprising a casing including a suction inlet, a pair of front wheels at the front of the casing and a pair of rear wheels at the rear of the casing, wherein the suction nozzle unit further comprises a shaft pin for rotatably supporting the front wheels, and means for moving the casing up and down relative to the shaft pin so as to vary the height of the front end of the casing relative to the surface to be vacuumed(e.g., a carpet). 
     Preferably, the moving means comprises a rotation shaft extending parallel to the shaft pin and mounted in the casing for movement up and down along with the casing, a rotation arm connecting the rotation shaft and the shaft pin together, and means for rotating the rotation shaft relative to the shaft pin to move the casing up and down. 
     Preferably, the rotating means comprises an operating lever extending radially from the rotation shaft, and a driving means for rotating the operating lever. 
     Preferably, the driving means comprises an adjusting knob disposed on the casing, having a shaft with a spiral groove formed in the outer circumference thereof and a handle provided at s first end of the shaft for rotating the shaft, and a slider member having a spiral rib on the inner circumference thereof engaging the spiral groove of said shaft and being mounted so as to move up and down along said shaft, responsive to rotation of said shaft, to thereby cause rotation of the operating lever. 
     Preferably, an engagement projection is provided at one end of the slider and is adapted to be engaged with the operating lever. 
     Preferably, the driving means further comprises a coil spring having a first end connected to the operating lever and a second end connected to a bottom wall of the casing, for resiliently biasing the operating lever in a upwardly direction away from the said bottom wall. 
     Preferably, the driving means further comprises rotational angle adjusting means for adjusting the rotational angle of the shaft. Preferably, the rotational angle adjusting means includes an adjusting protrusion extending outwardly from the second end of the shaft, and an adjusting protrusion receiving member provided in the casing and including a plurality of adjusting grooves for receiving the adjusting protrusion. 
     In accordance with a further aspect of the invention, a vacuum cleaner suction nozzle is provided wherein the unit comprises: a casing having a front end and a rear end, and including first and second front wheels at the front end of the casing, and at least one wheel located at the rear end of the casing and defining a rotation axis; first and second shaft pins for supporting said first and second front wheels for rotation about said first and second shaft pins, respectively; a shaft connecting said shaft pins together and being rotatable about said shaft pins; coupling means for coupling said shaft to said casing so that rotation of said shaft about said shaft pins produces pivoting of the casing about the axis of said at least one rear wheel and resultant elevation of the front end of said casing; and operator controlled control means for providing selected rotation of said shaft about said shaft pins to produce selected elevation of said front end of said casing. 
     Further features and advantages of the present invention will be set forth in, or apparent from, the detailed description of preferred embodiments thereof which follows. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded perspective view of a suction nozzle unit for a vacuum cleaner according to the present invention; 
     FIG. 2 is an enlarged perspective view of the part “A” of the suction nozzle unit in FIG. 1, indicated at “A” in FIG. 1; 
     FIG. 3 is a side elevational view, partially in cross section, of suction nozzle unit of FIG. 1; 
     FIG. 4 is a side elevational view, partially in cross section, of the elevated state of the suction nozzle unit of FIG. 3; 
     FIG. 5 which was described above, is a schematic side elevational view of a conventional vacuum cleaner; 
     FIG. 6 which was described above, is an exploded perspective view of a conventional suction nozzle unit for a vacuum cleaner; and 
     FIG. 7 which was described above, is a side elevational view, partially in cross section, of the conventional suction nozzle unit of FIG.  6 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIGS. 1 to  3 , there is shown a suction nozzle unit  1  for a vacuum cleaner constructed according to a preferred embodiment the present invention and comprised of a casing or housing  3  defining the external appearance of the unit  1 , respective pairs of front wheels  9  and rear wheels  6  for enabling the suction nozzle unit  1  to be moved over the surface to be cleaned, and a connector  7  to which a suction pipe (corresponding to the suction pipe  93  of FIG. 5) is coupled. 
     The casing  3  is comprised of a lower casing  10 , and an upper casing  20  when covers the lower casing  10 . In the front bottom part of the lower casing  10  is formed a suction inlet  11  for sucking dust and debris from the surface to be cleaned. 
     In the back of the suction inlet  11  are located a pair of oppositely disposed, substantially L-shaped partitioning walls  24 . Between side wall portions  24   a  of the partitioning walls  24  is formed a suction duct  13  which serves as a passageway for the dust and debris sucked through the suction inlet  11 . The top of the suction duct  13  is covered with a duct cover  23 . In the back of the suction duct  13  is positioned a connector receiving part  25  for rotatably receiving the connector  7 . In a part of the upper casing  20  covering the lower casing  10  is provided an opening or aperture  22  through which extends an adjusting knob  72  for a driving part  45  will be described later. 
     Between a front wall  10   a  and side walls  10   b  of the lower casing  10 , and front wall portions  24   b  of the partitioning walls  24  is formed a brush receiving part  15  in which is rotatably installed a brush member  27  for removing dust and debris from a carpet  87  as shown in FIG.  4 . The brush member  27  is rotated by a brush motor (not shown). 
     The rear wheels  6  disposed at the rear side walls of the lower casing  10  are coupled to wheel coupling parts  17  so as to roll along a carpeted surface to be cleaned. The front wheels  9  disposed at the front side walls of the lower casing  10  are supported by shaft pins  35  so as to roll along a carpeted surface. Relative up and down movement between the shaft pins  35  and the lower casing  10  is provided by an elevating mechanism  30 . More particularly, as referenced to the surface to be cleaned, the lower casing  10  is caused to move up and down relative to the shaft pins  35 . 
     As shown in FIG. 2, the elevating mechanism  30  is comprised of a rotation shaft  31 , rotation arms  33  and a rotation mechanism generally denoted  40 . The rotation shaft  31  is rotatably installed in a shaft housing part  12  formed on a bottom portion of the lower casing  10 , and extends parallel to the shaft pins  35  which rotatably support the front wheels  9 . The rotation arms  33  connect respective ends of the rotation shaft  31  to the shaft pins  35 . The rotation mechanism  40  rotates the rotation shaft  31  so that the rotation arms  33  rotate about shaft pins  35  and the ends of arms  33  connected to rotation shaft  31  move up and down relative to shaft pins  35 . As a result, the front portion of the lower casing  10  moves up and down relative to the surface to be cleaned. Preferably, the rotation shaft  31 , the rotation arms  33  and the shaft pins  35  are formed integrally in the shape of crankshaft. 
     The rotation mechanism  40  is comprised of an operating lever  41  and a driving part  45  for driving the operating lever  41 . The operating lever  41  is extends perpendicular to the rotation shaft  31  and projects to the backside of the lower casing  10  from the rotation shaft  31  through an opening  14  formed by cutting out an upper part of the shaft housing part  12 . 
     The driving part  45  is comprised of a slider receiving element  50  which extends vertically with respect to the lower casing  10  adjacent to the operating lever  41 , a slider member  60  slidably received in the slider receiving element  50  so as to rotate the operating lever  41  in response to the sliding movement thereof, and an adjusting knob  70  for adjusting the sliding movement of the slider member  60 . 
     The slider receiving element  50  has a rectangular cross section and is open at the top thereof. A vertical guide slit  51  is formed in one side wall of the slider receiving element  50 , and faces the operating lever  41 . 
     The slider member  60  has the shape of rectangular column, and along the center line thereof, a through hole or opening  63  is formed. On the lower part of the slider  60 , opposite to the guide slit  51  of the slider receiving element  50  is formed an engagement protrusion or projection adapted to engage the operating lever  41 , and extending through the guide slit  51  of the slider receiving elements  50 . A spiral rib or thread  65  is formed on the inner circumference of the through hole  63  in the slider  60 . 
     The adjusting knob  70  comprises a spiral or threaded shaft  73  and a handle  72  located at the top of the spiral shaft  73  for adjusting the rotation of the spiral shaft  73 . The shaft  73  has a spiral groove  75  at its outer circumference corresponding to the spiral rib  65  of the slider member  60 , and moves up and down in the through hole  63  of the slider  60 . A flange  74  is formed between the shaft  73  and the handle  72 . The lower surface of the flange  74  contacts the periphery of the hole  22  in the upper casing  20 , so that the movement of the adjusting knob  70  is prevented. With this arrangement, when the spiral shaft  73  rotates relative to the slider member  60 , the slider member  60  moves up and down in the slider receiving element  50 . In response to this movement, the engagement protrusion or projection  61  of the slider member  60  moves up and down along the guide slit  51  to rotate the operating lever  41  and to thus rotate the rotation shaft  31  and lift or lower the ends of the rotation arms  33  connected thereto, as shown in FIGS. 3 and 4. Casing  3  pivots around the axis of the rear wheels  6  and, as a result, the front part of the lower casing  10  moves up and down relative to the front wheels  9  and to the surface to be cleaned. 
     At the location of the slider receiving element  50  and the knob  70  is formed a rotational angle adjusting member  80  for adjusting a rotational angle of the knob  70  so as to adjust the amount of the relative movement provided wherein the front wheels  9  to the lower casing  10 . The rotational angle adjusting member  80  comprises an annular adjusting protrusion receiving element  81  provided on the bottom face of the slider receiving element  50 . Element  81  engages a lower part of the spiral shaft  73  of the adjusting knob  70 , and has a plurality of adjusting grooves  83  formed at uniformly paced intervals around the inner circumference thereof. An adjusting projection or protrusion  85  radially protrudes from a lower part of the spiral shaft  73  to engage with the adjusting grooves  83  of element  81 . 
     In the operation of the rotational angle adjusting member  80 , the adjusting protrusion  85  of the spiral shaft  73  engaged with one of adjusting groove  83  is caused to resiliently or elastically engage the next adjacent adjusting groove  83  of the adjusting protrusion receiving element  81  when the adjusting knob  70  is rotated by the user, so that the slider  60  moves by a desired distance. In this way, adjustment is provided of the movement of the lower casing  10  relative to the front wheels  9 . 
     The operating lever  41 , operated by the driving part  45 , is resiliently or elastically biased upwards by a compression coil spring  43 . The end of the coil spring  43  are respectively coupled to one end of the operating lever  41  and the bottom of the lower casing  10 . With this coupling arrangement, the coil spring  43  is extended upwardly when the operating lever  41  is moved upwardly in response according to the elevation of the slider  60  of the driving part  45 , and is compressed when the slider  60  of the driving part  45  is moved downwardly. 
     In operation, and assuming that the casing  3  is in the position shown in FIG. 3, when the handle  72  of the adjusting knob  70  is rotated in a first rotational direction, the spiral shaft  73  of the adjusting knob  70  is for example, rotated clockwise relative to the slider member  60  and the slider member  60  is slidably moved upwardly within the slider  60  the slider receiving element  50 . The engagement protrusion  61  of the lower part of the slider  60  also moves upwardly, so that the operating lever  41 , which is connected to the rotation shaft  31 , rotates upwardly in response to the restoring force produced by the coil spring  43 . As the rotation shaft  31  rotates upwardly together with the operating lever  41 , the rotation arms  33  also rotate upwardly. Accordingly, the front part of the lower casing  10 , which includes the suction inlet  11 , is separated from the surface  87  to be cleaned, as shown in FIG.  4 . 
     At this time, the adjusting protrusion or projection  85  of the spiral shaft  73  of the adjusting knob  70  is released from engagement with the adjusting grooves  83  of the adjusting protrusion receiving member  81  and rotates therein. If the user stops rotation of the knob  70 , the adjusting protrusion  85  becomes engaged with one of the plurality of adjusting grooves  83 . In this manner, the movement of the slider  60  relative to the knob  70 , and thus, the relative movement of the front part of the lower casing  10  with respect to the surface to be cleaned can be adjusted as desired. 
     If the adjusting knob  70  is rotated in the second, opposite direction, that is, counterclockwise, the slider  60  and the engagement protrusion  61  thereof, move downwardly, and the operating lever  41  also moves downwards compressing the coil spring  43 . The front part of the lower casing  10  then moves toward the front wheels  9  and the surface to be cleaned, and the distance or spacing between the lower casing  10  and the surface to be cleaned is made smaller. 
     According to the present invention, because the front part of the lower casing  10  can be elevated from the surface to be cleaned depending on the length of the pile  89  of the carpet  87 , as illustrated in FIG. 4, the resistance created when the carpet fibers  89  of the carpet  87  are pulled under the front bottom part of the lower casing in the conventional suction nozzle unit can be prevented, thereby improving the movability of the suction nozzle unit. 
     In the above-described embodiments, the elevating mechanism is comprised of the rotation shaft, the rotation arms, the operating lever, the adjusting knob and the slider. In an alternative, non-illustrated embodiment, the elevating mechanism can be comprised of a rack coupled to the shaft pin, a pinion engaged with the rack, and a driving motor for driving the pinion. A solenoid (not shown) can also be used to provide the driving force for the elevating mechanism. The shaft pin may also be installed to slidably move in the casing of the suction nozzle unit. 
     Although the present invention has been described in connection with a preferred embodiments thereof, it will be appreciated by those skilled in the art that additions, modifications, substitutions and deletions not specifically described hereinabove can be made in this embodiment without departing from the spirit and scope of the invention.