Abstract:
A changeover valve, for an upright vacuum cleaner, comprises a movable valve member ( 31 ) connected via a flexible duct to a dirt separator of the cleaner, and a valve body ( 30 ) having inlet ports ( 32, 33 ) connected, respectively, to an air inlet in the underside of a floor-engaging unit of the cleaner and, via a flexible hose, a suction nozzle of the cleaner. The valve member ( 31 ) is movable relative to the valve body ( 30 ) for selective alignment with either of the inlet ports ( 32, 33 ).

Description:
BACKGROUND OF THE INVENTION 
   This invention relates to a vacuum cleaner and to a suction changeover valve for the vacuum cleaner. 
   Known vacuum cleaners are either of the so-called upright type or the so-called cylinder type. Upright vacuum cleaners comprise an upright body pivotally connected at its lower end to a wheeled floor-engaging unit for partial rotation forwardly and rearwardly about a transverse axis. The upright body encloses a motor/fan unit which develops suction for drawing air through an inlet in the floor-engaging unit of the cleaner and then through a dust separation device. A handle is provided at the upper end of the upright body for manoeuvring the cleaner. A motor-driven, rotary agitator brush is mounted across the inlet in the floor-engaging unit to beat and sweep the floor in the region of the airflow into the cleaner. 
   Cylinder vacuum cleaners comprise a body which encloses a motor/fan unit which draws air into a dust separation device though an elongate flexible hose. A plurality of tools are provided for fitting to the end of the hose. 
   Upright vacuum cleaners are better at cleaning carpets than cylinder vacuum cleaners because of the action of the rotating agitator brush. However, cylinder vacuum cleaners are better suited for above-floor cleaning and for cleaning in places where an upright cleaner cannot be used. 
   In order to provide a cleaner having the advantages of both upright and cylinder cleaners, it is known to provide an upright cleaner having an elongate flexible hose, the inlet of which can either be connected to the floor-engaging unit of the cleaner for conventional floor cleaning, or connected to an extension tube and/or cleaning tools for above-floor cleaning. 
   A disadvantage of this arrangement is that during conventional floor cleaning, the airflow though the cleaner is partially restricted by the elongate flexible hose, which is coiled for storage on the back of the cleaner. The coiled length of hose is also susceptible to blockage. 
   In order to overcome the above-mentioned problem, vacuum cleaners of the upright type are known which comprise a hose and a valve which can be actuated such that the suction is either applied to the hose for above-floor cleaning or to the floor-engaging unit of the cleaner for conventional floor cleaning. 
   European Patent No. 1,121,043 discloses an upright cyclonic vacuum cleaner of the above-mentioned type, comprising an elongate rigid tube, which is mounted vertically to the rear of the cleaner body and which forms a handle for manoeuvring the cleaner during conventional floor cleaning. The cyclonic separator is connected to the outlet of a first member of a two-way valve. The valve further comprises a second valve member having a first inlet port connected to the air inlet on the underside of the floor-engaging unit and a second inlet port connected to the elongate rigid tube. 
   The valve is arranged to connect the cyclonic separator to the air inlet on the underside of the floor-engaging unit when the upright body of the cleaner is pivoted rearwardly relative to the floor-engaging unit of the cleaner. In order to carry out above-floor cleaning, the upright body of the cleaner is pivoted forwardly into its upright position relative to the floor-engaging unit of the cleaner, to divert the suction airstream from the floor-engaging unit of the cleaner to the elongate rigid tube. 
   The outlet port of the first member of the valve is provided with a resilient seal. Wear and potential damage to the seal due to sliding contact with the second valve member is eliminated by providing a cam-and-follower mechanism whereby the seal is disposed out of sliding contact with the second valve member during changeover movements. This mechanism adds to the complexity of the valve. 
   U.S. Pat. No. 5,732,439 discloses a valve comprising a flap, which is responsive to the attitude of the cleaner handle (whether rearwardly inclined for floor cleaning, or upright for above-floor cleaning) to route the suction airstream to the separator unit from one or other of two inlets. The valve comprises a pivoted flap located in a chamber to which the separator inlet duct, and dirty air ducts from the floor nozzle and hose respectively, are connected. Dependent on the momentary position of the flap, one of the dirty air inlets is blocked whilst the other dirty air inlet remains open. The valve responds to a change in attitude of the cleaner handle, between upright and inclined positions, to switch the dirty air path from one dirty air inlet to the other. The mechanism required to effect reliable operation of such valve arrangements, with acceptable levels of sealing, is relatively complex, involving cams, springs and linkages to actuate the flap. 
   Alternative actuating mechanisms for changeover flap valves are known whereby removal of above-floor cleaning apparatus from its stored position on the body of the cleaner gives rise to switching of the valve. Such an arrangement is disclosed in United Kingdom Patent No. 2,291,336. Manually operable valves are also known. 
   SUMMARY OF THE INVENTION 
   We have now devised a vacuum cleaner having a changeover valve which is less complicated than changeover valves hitherto known in vacuum cleaners. 
   In accordance with this invention, as seen from a first aspect, there is provided a vacuum cleaner comprising: 
   a floor-engaging unit having a first air inlet on the underside thereof: 
   an upright body pivotally connected at its lower end to said floor-engaging unit; 
   a detachable handle upstanding from said upright body and having a rigid tubular duct extending between a second air inlet at one end of the handle and an outlet disposed remote from said one end; 
   an elongate flexible hose having a first end and a second end, the first end of the hose being connected to said outlet on said handle; and 
   a changeover valve comprising a movable valve member having an airflow outlet connected via a flexible duct to a separator for separating dirt and dust from an airflow through the cleaner, and a valve body having a first airflow inlet connected to said first air inlet on the underside of said floor-engaging unit and a second airflow inlet connected to said second end of said elongate flexible hose, said valve member being movable relative to the valve body for selective alignment of said airflow outlet with either of said airflow inlets. 
   The flexible duct permits the valve member to move relative to the valve body to switch the airflow between the first and second air inlets for floor and above-floor cleaning, respectively. 
   Preferably the first and second airflow inlets of the valve body extend at an inclined angle of preferably 90 degrees to each other, said valve member being rotatable relative to said valve body for selective alignment with said airflow inlets. 
   Preferably the valve member is moved by means arranged to engage said handle, such that removal of the handle for above-floor cleaning switches the airflow from the first air inlet to the second air inlet. 
   The airflow outlet of the movable valve member is preferably provided with a circumferential, resilient seal for sealing against valve seats with which the valve body is formed, for said first and said second airflow inlets of the valve. 
   Preferably the seal is out of contact with the valve seats of said first and second airflow inlets of the valve during relative movement of the valve member. 
   In one embodiment, the valve member is further arranged to move axially relative to said first and second airflow inlets during changeover, in order to prevent wear and to provide improved sealing. 
   In an alternative embodiment, the seal is arranged such that when suction is applied to the valve, a pressure differential arises across an edge zone of the seal to cause the seal to be brought into contact with the respective valve seat of the valve body. 
   Preferably the seal comprises a substantially annular lip, the lip normally extending radially outwardly and arranged to deform axially outwardly to seal against the respective valve seat of the valve body when suction is applied to the valve. 
   Also in accordance with this invention, as seen from a second aspect, there is provided a changeover valve comprising a first valve member having a first port, and a second valve member having second and third ports, said valve members being movable relative to each other for selective alignment of said first port with either of said second and third ports, a seal being provided on said first valve member which is normally out of contact with said second valve member when suction is applied to the valve via one of said ports. 
   Preferably the seal comprises a substantially annular lip, the lip normally extending radially outwardly and arranged to deform axially outwardly to seal against the second valve member when suction is applied to the valve. 
   An embodiment of the invention will now be described by way of example only and with reference to the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a side view of an upright vacuum cleaner in accordance with this invention, the cleaner being shown when configured for floor cleaning; 
       FIG. 2  is a similar view of the cleaner, when configured for above-floor cleaning; 
       FIG. 3  is sectional view through a changeover valve of the vacuum cleaner; and 
       FIG. 4  is a perspective view of a movable valve member of the valve of  FIG. 3 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring firstly to  FIGS. 1 and 2  of the drawings, there is shown an upright vacuum cleaner which comprises an upright body  10  pivotally mounted, at its lower end, to a floor-engaging unit  11 , enabling partial rotation of the upright body  10  forwardly and rearwardly relative to the floor-engaging unit  11 , about an axis which extends transverse the cleaner. A motor/fan unit is housed within the body  10 , to develop suction for drawing air into the cleaner and though a cylindrical, cyclone separation unit  14 , which is mounted to the front of the body  10  and serves to separate dirt and dust from the incoming airflow and to collect this dirt and dust. A first suction inlet  13  is provided on the underside of the floor-engaging unit  11  and a motor-driven, rotary agitator brush (not shown) is mounted across the unit  11 , in the inlet  13 . The floor engaging unit  11  is provided with a pair of floor-engaging wheels  11   a.    
   The cleaner further comprises an elongate handle  12  which is shown, in  FIG. 1 , inserted into a vertical socket  16  formed in the rear of the upright body  10  of the cleaner. A catch  17  is provided, adjacent the top of the socket  16 , to engage a barb  18  on the side of the handle  12 , to retain the latter in the socket  16 . The catch  17  may be released manually, to enable the handle  12  to be removed from its socket  16 . The handle  12  comprises a tubular suction inlet  20  formed at its rearward end as a handgrip  19 : the forward end of the tubular suction inlet  20  is tapered and changes from a circular cross-section to form a so-called crevice tool  21 . A flexible suction hose  26  is connected at one end to an outlet  25  formed in the side of the tubular suction inlet  20 , adjacent its junction with the handgrip  19 , and is connected at its other end to the upright body  10  of the cleaner. When the handle  12  is retained in its socket  16 , the handgrip  19  serves for manoeuvring the cleaner over the floor: when the handle  12  is removed from its socket  16 , the handgrip  19  serves for manoeuvring the tool  21 . 
   A changeover valve is housed within the upright body  10  of the cleaner, and in one position serves to communicate suction to the inlet  13  in the floor-engaging unit  11  for use of the cleaner in floor cleaning, whilst in a second position serves to communicate suction to the flexible hose  26  and hence to the suction inlet  20  and tool  21  for use of the cleaner in above-floor cleaning. When the handle  12  is inserted into the socket  16 , as shown in  FIG. 1 , its end bears on an actuating member of the changeover valve and depresses this actuating member against a spring bias: depression of the actuating member serves to hold the valve in its first position, in which suction is communicated to the inlet  13  in the floor-engaging unit  11 . When the handle  12  is removed from the socket  16 , as shown in  FIG. 2 , the actuating member of the valve is free to move under its spring bias, and changes the valve to its second position, in which suction is communicated to the tool  21  via the flexible hose  26 . 
     FIGS. 3 and 4  show the changeover valve of the vacuum cleaner. Referring to  FIG. 3 , the valve comprises a movable valve member  31  and a valve body  30 . The valve member  31  is tubular and is rotatably mounted to the valve body  30  for rotation about an axis A-A which extends perpendicular to a flow duct extending through the valve member  31 . 
   The valve body  30  comprises a first air inlet port  32  of tubular form, connected to the air inlet  13  on the underside of the floor-engaging unit  11  of the cleaner, and a second air inlet port  33  of tubular form, connected via the flexible hose  26  to the tool  21  for above-floor cleaning. The ports  32 ,  33  are arranged at 90 degrees to each other. 
   The valve member  31  is connected at one end  31   a  to the dust separation device via a flexible hose  36  which allows the first valve member  31  to rotate freely. 
   The opposite end of the valve member  31  is arcuate in side view and is provided with a circumferential seal  34  for sealing against the valve body  30 , and in particular against annular seats with which the valve body is formed, at the inner ends of the respective tubular inlet ports  32 ,  33 , these seats also being arcuate in side view to complement the arcuate end profile of the valve member  31 . 
   Referring to  FIG. 4  of the drawings, the seal  34  comprises a lip  35  which normally extends radially outwardly in its as-formed condition but which is arranged to deform axially outwardly to seal against one or other of the annular seats of the valve body  30  when suction is applied to the valve. 
   In its normal configuration, the lip  35  is disposed a small distance away from the valve body  30  and thus the valve member  31  can rotate freely between the ports  32 ,  33 . This also prevents wear on the seal  35 . However, when the valve member  31  is aligned with one of the ports  32  or  33  and the cleaner is activated, the suction applied to the valve causes the lip  35  to deform axially outwardly to seal against the respective annular seat of the valve body  30 . 
   It will be appreciated that the changeover valve which has been described is of simple construction yet effective in use and its sealing arrangement will experience minimal wear.