Abstract:
A vacuum cleaning tool has a housing with a partition dividing an interior of the housing into a brush chamber and a turbine chamber. A vacuum connector is connected to the housing remote from the brush chamber. A working roller is arranged in the brush chamber. An air turbine is arranged in the turbine chamber and drives in rotation the working roller. A vacuum air flow enters the brush chamber, flows from the brush chamber through an intake window into the turbine chamber, flows within the turbine chamber through the air turbine, and exits from the turbine chamber to the vacuum connector. The turbine chamber has a chamber bottom with a ramp ascending toward the outlet window in the area where the vacuum airflow exits from the turbine chamber. The ramp is through-shaped and has a groove extending in the flow direction of the vacuum airflow.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The invention relates to a vacuum cleaning tool for a vacuum cleaning device comprising a housing in which a brush chamber and a turbine chamber are provided. A working roller, in particular, a brush roller, is arranged in the brush chamber transversely to the working direction of the vacuum cleaning tool. The working roller penetrates with a peripheral portion a suction slot provided in the bottom of the brush chamber. An air turbine is arranged in the turbine chamber for driving in rotation the working roller. A vacuum air flow of the vacuum cleaning tool enters the brush chamber via the suction slot, flows into the turbine chamber via an intake window provided in a partition between the brush chamber and the turbine chamber, and exits from the turbine chamber through an outlet window of a vacuum connector. In the flow direction of the vacuum airflow, the outlet window is positioned higher than the intake window. The turbine chamber has a chamber bottom and the chamber bottom has a ramp ascending toward the outlet window in the area where the vacuum airflow exits from the turbine chamber.  
           [0003]    2. Description of the Related Art  
           [0004]    In the housing of the vacuum cleaning tool according to U.S. Pat. No. 5,249,333, a brush chamber and a turbine chamber are formed. In the brush chamber a brush roller is arranged transversely to the working direction and penetrates to the exterior through a suction slot in the housing bottom of the brush chamber. For driving in rotation the brush roller, an air turbine is arranged in the turbine chamber which drives the brush roller by means of a belt drive. A vacuum airflow enters the brush chamber through the suction slot and flows into the turbine chamber through an intake window in the partition between the brush chamber and the turbine chamber. The vacuum air flow exits from the turbine chamber through an outlet window. The air turbine is formed as a so-called direct flow turbine, i.e., between two neighboring vanes a flow path is formed which opens into the center of the air turbine. The vacuum air flow therefore enters the vane-free center of the air turbine by flowing through the annular vane arrangement at one end and performs again work when exiting this center at the opposite end by flowing again through the annular vane arrangement.  
           [0005]    This known configuration of a vacuum cleaning tool ensures a great output of the air turbine which, for strong vacuum air flows, is within the magnitude of an electric motor which can be used as an alternative for driving the brush roller.  
         SUMMARY OF THE INVENTION  
         [0006]    It is an object of the present invention to further develop the vacuum cleaning tool of the aforementioned kind such that even for weaker vacuum air flows a strong turbine power output for driving the working roller is made available.  
           [0007]    In accordance with the present invention, this is achieved in that the ramp provided on the turbine chamber bottom is trough-shaped with a groove extending in the flow direction of the vacuum airflow.  
           [0008]    In the flow direction of the vacuum airflow the outlet window is positioned higher than the intake window so that the vacuum airflow is directed upwardly toward the outlet window. In this way, the vacuum airflow safely passes through the annular vane arrangement, enters the center of the turbine, and safely exits this center again. In the outflow area of the vacuum airflow the turbine chamber bottom is formed as a ramp and ascends to the outlet window wherein in the flow direction of the vacuum airflow the terminal edge of the ramp is positioned approximately at the level of the housing edge of the outlet window. In this way, the fault flow or secondary air which flows near the turbine chamber bottom is also guided in a directed way to the outlet window and can flow out without disruption. The deflected fault flow or secondary air therefore cannot impede the outflow of the vacuum airflow, which performs the work, so that indirectly the turbine power output is increased in this way.  
           [0009]    The ramp is expediently trough-shaped with a groove extending in the flow direction of the vacuum airflow wherein the groove advantageously is matched in the area of the air turbine to the width of the air turbine and at the outlet side to the size of the outlet window. In this connection, the trough-shaped groove can be guided into the outlet window, in particular, can penetrate into it.  
           [0010]    Preferably, the center of the outlet window is located as a point on the straight extension of the ramp surface which preferably symmetrically divides the outflow window at its center.  
           [0011]    In a further embodiment of the invention a connecting line between the upper edge of the outflow window and the upper edge of the intake window is positioned below the hub of the air turbine. The circle segment of the air turbine cross-section which is separated by this connecting line has a surface area which is approximately 30% to 45% of the cross-sectional surface area of the air turbine.  
           [0012]    When the annular vane arrangement has approximately 10 to 14 vanes and a connecting line is drawn between approximately the center of the intake window and approximately the center of the outlet window, this connecting line will intersect the air turbine as a secant. The circle segment which is separated by the secant has a circular arc which corresponds to the spacing of four to six, preferably five vanes, of the annular vane arrangement of the air turbine. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0013]    In the drawing:  
         [0014]    [0014]FIG. 1 is a longitudinal section of a first embodiment of a vacuum cleaning tool according to the invention;  
         [0015]    [0015]FIG. 2 is an enlarged perspective illustration of a detail of the vacuum cleaning tool according to FIG. 1;  
         [0016]    [0016]FIG. 3 is a longitudinal section of a second embodiment of a vacuum cleaning tool according to the invention; and  
         [0017]    [0017]FIG. 4 is a perspective illustration of the vacuum cleaning tool according to FIG. 3. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0018]    The illustrated vacuum cleaning tools according to FIGS. 1 through 4 have the same basic configuration which is therefore explained only in connection with FIG. 1.  
         [0019]    The vacuum cleaning tool  1  has a housing  4  which is comprised of a bottom housing part  2  and a top housing part  3 . In the housing  4  a brush chamber  5  and a turbine chamber  6  are provided. In the working direction  7  of the vacuum cleaning tool  1  the brush chamber  5  is arranged at the leading end and has a working roller  11  arranged therein extending transversely to the working direction  7 . In the illustrated embodiment the working roller  11  is a brush roller. The brush roller  11  has a bristle arrangement  12  which penetrates with its peripheral portion  10  a suction slot  9  provided in the housing bottom  8 . The suction slot  9  extends transversely to the working direction  7  across the entire width of the vacuum cleaning tool  1 .  
         [0020]    In the inferior of the housing  4 , the brush chamber  5  is separated from the turbine chamber  6  by an inner partition  13 . An intake window  14  is provided within the partition  13  near the bottom  28  of the turbine chamber  6 , and in the illustrated embodiment it is positioned at the level of the turbine chamber bottom  28 . The turbine chamber bottom  28  thus forms a boundary the intake window  14 .  
         [0021]    An air turbine  15  is arranged in the turbine chamber  6  which is driven by a vacuum airflow  19 . The air turbine  15  has an axis of rotation  16  positioned transversely to the working direction  7  and is secured and supported in the axial sidewalls  13 ′ of the turbine chamber  6 . By means of the belt drive  18 , which is only schematically illustrated, the air turbine  15  drives in rotation the working roller  11  about its bearing axle  17 . The turbine chamber  6  has at its end facing away from the partition  13  a vacuum connector  23  whose tube end is rotatably supported about an axis of rotation  29  in a part-cylindrical swivel part  25 . The swivel part  25  is movable about a swivel axis  30  so that the vacuum connector  23  can be moved up and down. The outlet window  24  of the vacuum connector  23  is positioned within the swivel part  25  such that the center of the outlet window  24  is at the same time the point of intersection of the swivel axis  30  of the swivel part  25  and of the axis of rotation  29  of the vacuum connector  23 .  
         [0022]    The annular vane arrangement  21  of the air turbine  15  has a plurality of vanes  20  arranged about its circumference at an equidistant spacing to one another, wherein preferably approximately 10 to 14 such vanes  20  are arranged within the annular vane arrangement  21 . In the illustrated embodiment,  12  such vanes  20  are provided. Between neighboring vanes  20 , open flow paths  22  are formed which open toward the center  50  of the air turbine  15  so that the vacuum airflow  19  on its way from the intake window  14  to the outlet window  24  will flow through the vane-free center  50  of the air turbine  15 .  
         [0023]    In order to ensure flow of the vacuum airflow  19  through the air turbine  15 , it is suggested to position the mantle surface  48  of the air turbine  15  at a minimal distance a from the turbine chamber bottom  28 . The lower edge  36  of the intake window  14  is positioned approximately at the level of the turbine chamber bottom  28  while the upper edge  26  of the intake window  14  in the flow direction is positioned approximately below the lower edge  27  of the outlet window  24 . In this connection, the cross-section of the preferably circular outlet window  24  is larger, preferably several times larger, than the cross-section of the preferably rectangular intake window  14 .  
         [0024]    A connecting line  45  between the upper edge  37  of the outlet window  24  and the upper edge  26  of the intake window  14  extends below the axis of rotation  16  or the hub  39  of the air turbine  15 . The connecting line  45  separates a circle segment  44  from the cross-section of the air turbine  15  wherein the surface area of the circle segment  44  is approximately 30% to 45% of the cross-sectional surface area of the air turbine  15 .  
         [0025]    In order to provide a high power output of the air turbine  15 , it is proposed to configure in particular the outlet area of the turbine chamber  6  in a flow-enhancing way. Since the outlet window  24  is positioned higher than the intake window  14 , the height difference must be bridged in a flow-enhancing way. For this purpose, it is proposed to embody the turbine chamber bottom  28  in the outlet area of the turbine chamber  6  as a ramp  31  which ascends toward the outlet window  24 . In the flow direction of the vacuum airflow  19 , the terminal edge  33  of the ramp  31  is positioned at the level of the housing edge  34  or the lower edge  27  of the outlet window  24  or the vacuum connector  23 . In order to provide also a lateral guiding of the vacuum airflow  19  into the outlet window  24 , the ramp  31  is trough-shaped with a groove  32  extending in the flow direction of the vacuum airflow  19 . In this connection, as illustrated in particular in FIGS. 2 and 4, the maximum opening width W of the groove  32  measured transverse to the flow direction of the vacuum airflow  19  is slightly greater than the width B of the air turbine  15  measured in the direction of the axis of rotation  16 . The opening width of the groove  32  near the air turbine  15  is greater than at the outlet end facing the outlet window  24 . As illustrated in FIG. 2, the groove  32  tapers from its maximum opening width W in the area of the air turbine  15  to its outlet width A at the outlet window  24 . For a lateral guiding action at the outlet end of the groove  32 , sidewalls  35  are provided which extend to approximately half the height of the outlet window  24  (FIG. 1). Expediently, the terminal edge  33  projects past the housing edge  34  by an amount s, as shown in FIG. 2. The trough-shaped groove  32  can also extend into the outlet window  24 , in particular, can penetrate into it, in order to avoid power-reducing air turbulence in the area of the transition of the groove  32  into the outlet window  24 . At the level of the outlet window  24 , respectively, shortly before the outlet window  24 , the cross-section of the groove  32  corresponds to approximately half a cross-section of the outlet window  24 . The groove cross-section or the terminal edge  33  of the groove  32  in the flow direction of the vacuum airflow  19  substantially covers the edges of the outlet window  24  or the housing edge  34  of the outlet window  24 .  
         [0026]    The base  31 ′ of the ramp  31  is positioned in the flow direction of the vacuum airflow  19  downstream of the axis of rotation  16  and ascends from there substantially uniformly up to the level of the housing edge  34 . The air that is flowing at the level of the air turbine  15  is already guided in the area of the ramp base  31 ′ in the direction toward the outlet window  24  so that a good direction of the exiting vacuum airflow is provided. In addition to the direction of the vacuum airflow in the direction of the outlet window  24 , the groove  32  o provides a collecting function. In the outlet area of the vacuum air flow  19  from the annular vane arrangement  21 , non-directional flow portions of the vacuum airflow  19  are caught and guided in the direction toward the outlet window  24 . The close positioning of the mantle surface  48  of the air turbine  15  relative to the turbine chamber bottom  28  ensures in connection with the ramp  31  an easy flow action through the air turbine  15 . The area between the turbine chamber bottom  28  and the mantle surface  48  of the air turbine  15  presents a disturbing resistance for the vacuum air flow  19  so that the vacuum airflow  19  is instead forced through the air turbine  15  in a power-increasing way. In this connection, the ramp at the outlet of the vacuum air flow provides an ordered flow into the vacuum connector  23  wherein, as a result of the selected large cross-section of the outlet window  24 , a resistance disturbing the exit flow is substantially prevented.  
         [0027]    As a result of the arrangement of the air turbine  15  at the level of the longitudinal center axis  38  an excellent initial position for an power-efficient operation is selected. The longitudinal center axis  38  is positioned at the level of the axis of rotation  29  of the vacuum connector  23 . The center Z of the outlet window  24  is positioned also on or near the longitudinal center axis  38 .  
         [0028]    The embodiment according to FIGS. 3 and 4 differs in regard to the length of the ramp from the embodiment according to FIGS. 1 and 2. For same parts the same reference numerals are used.  
         [0029]    The ramp  131  ends at a spacing x before the housing edge  34  of the outlet window  24 . The embodiment of the ramp is configured such that the center Z is a point on the extension  46  of the ramp surface. As a result of the selected incline of the ramp  31  with alignment of the ramp surface relative to the center Z of the outlet window  24 , the spacing x can be bridged without causing great air turbulence. Such a spacing x to the ramp  131  is expedient for a larger movement range of the swivel part  25  in order to increase the movability of the socket of the vacuum connector  23 .  
         [0030]    An advantageous spatial arrangement of the outlet window  24 , the intake window  14 , and the air turbine  15  results when the annular vane arrangement  21  of the air turbine comprises approximately 10 to 14, preferably 12, vanes and when a connecting line  40  between approximately the center of the intake window  14  and approximately the center of the outlet window  24  intersects the cross-section of the air turbine  15  as a secant  41 . The circle segment  43  separated by the secant  41  has a circular arc  42  whose length corresponds to the spacing of four to six, preferably five vanes  20 .  
         [0031]    The ramp  31  has a ramp surface  47  whose extension line  46  extends through the center of the outlet window  24 . Preferably, the imaginary extension line  46  of the ramp surface  47  divides the outlet window  24  at the center, in particular, symmetrical thereto.  
         [0032]    While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.