Patent Publication Number: US-2006016043-A1

Title: Electric vacuum cleaner and cyclonic dust collecting apparatus

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to an electric vacuum cleaner and a cyclonic dust collecting apparatus to be mounted in the electric vacuum cleaner.  
      2. Description of the Related Art  
      Electric vacuum cleaners include, for example, a main body having an electric fan, a suction member to be moved along a floor surface, and a connection hose which connects the suction member to the main body, and a disposable filter bag is mounted in the main body. When an electric vacuum cleaner of this type is driven, outside air (air on the floor surface) is sucked from the suction member by driving the electric fan provided in the main body, and taken into the main body from a suction port of the main body through the connection hose. An inlet of the disposable filter provided in the main body communicates with the suction port. When the air sucked from the suction port passes through the disposable filter, dust entrained in the air is captured by the disposable filter (see, for example, Japanese Examined Utility Model Publication No. 5-20279 (1993)).  
      However, the electric vacuum cleaners of this type are uneconomical and disadvantageous in terms of environmental protection, because the cleaners utilize the disposable filter. Further, the disposable filter is not replaced until a certain amount of dust is collected in the filter. Therefore, the suction force and hence the dust collecting efficiency are reduced, as the amount of the collected dust is increased.  
      There has recently been known an electric vacuum cleaner including a cyclonic dust collecting apparatus which is capable of swirling air sucked from a suction port to separate dust from the air by a centrifugal force and capture the dust. The dust collected in the cyclonic dust collecting apparatus can be easily discarded by detaching the dust collecting apparatus from a main body and performing a predetermined operation. The electric vacuum cleaner including the cyclonic dust collecting apparatus is advantageous in that the reduction of the dust collecting efficiency is prevented by frequently discarding the dust collected in the cyclonic dust collecting apparatus (e.g., whenever the cleaner is used for a cleaning operation).  
      With the electric vacuum cleaner including the cyclonic dust collecting apparatus, however, it is cumbersome to detach the dust collecting apparatus and discard the collected dust whenever the cleaning operation is performed.  
      Hence, there is a demand for an electric vacuum cleaner with a cyclonic dust collecting apparatus, which is improved so as to prevent the reduction of the dust collecting efficiency even if dust is collected in the cyclonic dust collecting apparatus.  
      For more convenience, it is desirable to improve the electric vacuum cleaner with the cyclonic dust collecting apparatus so that a disposable filter can be temporarily used.  
     SUMMARY OF THE INVENTION  
      In view of the foregoing, it is a first object of the present invention to provide an electric vacuum cleaner and a dust collecting apparatus which are improved in dust collecting efficiency.  
      It is a second object of the present invention to provide an electric vacuum cleaner and a dust collecting apparatus which are improved in convenience.  
      It is a third object of the present invention to provide an electric vacuum cleaner and a dust collecting apparatus which are improved in ease of removing dust collected in the dust collecting apparatus.  
      An electric vacuum cleaner according to the present invention comprises a main body including an electric fan incorporated therein, and a dust collecting apparatus removable from the main body.  
      The dust collecting apparatus comprises a suction port, a cyclonic flow path for swirling air sucked from the suction port to separate dust from the air by a centrifugal force, a dust collecting chamber in which the separated dust is collected, an air outlet port provided in a wall of the dust collecting chamber for discharging the air sucked from the suction port, and a filter attached to the air outlet port. The main body has a wall opposed to the wall of the dust collecting chamber and having an opening smaller than the air outlet port in opposed relation to the air outlet port for feeding the air downstream by the electric fan. The air outlet port has a region opposed to the opening and a region not opposed to the opening, and a guide passage is provided for guiding air discharged from the region of the air outlet port not opposed to the opening toward the opening.  
      The inventive electric vacuum cleaner is adapted to selectively utilize the cyclonic dust collecting apparatus and a disposable dust collecting apparatus having a mouth cardboard and a filter bag attached to the mouth cardboard. The main body has an accommodating portion for accommodating either of the dust collecting apparatuses, and the accommodating portion has a fixing member for fixing the disposable dust collecting apparatus when the disposable dust collecting apparatus is mounted in the main body. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a sectional view of an electric vacuum cleaner according to a first embodiment of the present invention, the sectional view being taken along an anteroposterior vertical plane and seen from a right side;  
       FIG. 2  is a sectional view of the electric vacuum cleaner taken along a horizontal plane and seen from an upper side;  
       FIG. 3  is a perspective view of a filter holder as obliquely seen from a front upper side;  
       FIG. 4  is a perspective view illustrating the filter holder and a filter held by the filter holder partly in section taken along a horizontal plane;  
       FIG. 5  is a sectional view of an electric vacuum cleaner according to a second embodiment of the present invention, the sectional view being taken along an anteroposterior vertical plane and seen from a right side;  
       FIG. 6  is a plan view of the electric vacuum cleaner of  FIG. 5  with its dust cover removed;  
       FIG. 7  is a sectional view of the electric vacuum cleaner of  FIG. 5  taken along the anteroposterior vertical plane and seen from the right side with a disposable filter mounted therein;  
       FIG. 8  is a front view of a dust collecting apparatus to be mounted in the electric vacuum cleaner of  FIG. 5 ;  
       FIG. 9  is a right side view of the dust collecting apparatus;  
       FIG. 10  is a sectional view of a portion A in  FIG. 8 ;  
       FIG. 11  is a sectional view of the electric vacuum cleaner of  FIG. 5  taken along the anteroposterior vertical plane and seen from the right side with the dust collecting apparatus to be mounted therein;  
       FIG. 12  is a sectional view of the electric vacuum cleaner of  FIG. 5  taken along the anteroposterior vertical plane and seen from the right side with the dust collecting apparatus mounted therein;  
      FIGS.  13 ( a ) and  13 ( b ) are diagrams respectively illustrating states of a packing deformed when the dust collecting apparatus is mounted and when the disposable filter is mounted;  
      FIGS.  14 ( a ) and  14 ( b ) are diagrams illustrating a variation of the packing;  
       FIG. 15  is a plan view of an electric vacuum cleaner according to a first variation of the second embodiment with its dust cover removed;  
       FIG. 16  is a sectional view of an electric vacuum cleaner according to a second variation of the second embodiment with neither the dust collecting apparatus nor the disposable filter mounted therein, the sectional view being taken along an anteroposterior vertical plane and seen from a right side;  
       FIG. 17  is a sectional view of a dust cover as seen along a line D-D in  FIG. 16 ;  
       FIG. 18  is a sectional view of the electric vacuum cleaner of  FIG. 16  taken along the anteroposterior vertical plane and seen from the right side with the disposable filter mounted therein;  
       FIG. 19  is a sectional view of the electric vacuum cleaner of  FIG. 16  taken along the anteroposterior vertical plane and seen from the right side when the dust cover is to be closed with the dust collecting apparatus mounted in the cleaner;  
       FIG. 20  is a sectional view of the electric vacuum cleaner of  FIG. 16  taken along the anteroposterior vertical plane and seen from the right side when the dust cover is completely closed with the dust collecting apparatus mounted in the cleaner;  
       FIG. 21  is a sectional view of an electric vacuum cleaner according to a third variation of the second embodiment with neither the dust collecting apparatus nor the disposable filter mounted therein, the sectional view being taken along a horizontal plane and seen from an upper side;  
       FIG. 22  is a sectional view taken along a line E-E in  FIG. 21  with neither the dust collecting apparatus nor the disposable filter mounted in the electric vacuum cleaner;  
       FIG. 23  is a sectional view taken along the line E-E in  FIG. 21  with the disposable filter mounted in the electric vacuum cleaner;  
       FIG. 24  is a sectional view of the electric vacuum cleaner of  FIG. 21  taken along the horizontal plane and seen from the upper side with the dust collecting apparatus mounted therein;  
       FIG. 25  is a sectional view taken along a line F-F in  FIG. 24  with the dust collecting apparatus mounted in the electric vacuum cleaner;  
       FIG. 26  is a vertical sectional view of an upright electric vacuum cleaner to which the present invention is applied, the vertical sectional view being seen from a right side;  
       FIG. 27  is a back view of a main body of the upright electric vacuum cleaner of  FIG. 26  with a dust collecting apparatus detached;  
       FIG. 28  is a right side view of the detached dust collecting apparatus; and  
       FIG. 29  is a front view of the dust collecting apparatus with a filter cover being opened. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
      The present invention will hereinafter be described in detail with reference to the attached drawings.  
       FIG. 1  is a sectional view of an electric vacuum cleaner  1  according to a first embodiment of the present invention, the sectional view being taken along an anteroposterior vertical plane and seen from a right side.  FIG. 2  is a sectional view of the electric vacuum cleaner  1  taken along a horizontal plane and seen from an upper side. A left side and a right side in  FIG. 1  are respectively defined as a front side and a rear side of the electric vacuum cleaner  1 . An upper side and a lower side in  FIG. 2  are respectively defined as a left side and a right side of the electric vacuum cleaner  1 .  
      Referring to  FIGS. 1 and 2 , the electric vacuum cleaner  1  includes a main body  3  having an electric fan  2 , and a connection hose  5  having one end inserted into a suction port  4  provided at a front end of the main body  3  (in  FIG. 2 , the connection hose  5  is not shown). The connection hose  5  is an elongated tubular member with at least a part thereof having a bellows shape. Though not shown, a suction member is attached to the other end of the connection hose  5 . When a cleaning operation is performed, the suction member is moved along a floor surface with the electric fan  2  in the main body  3  being driven. Thus, dust on the floor surface is sucked together with air from the suction member. The air sucked from the suction member flows through the connection hose  5  into the main body  3  from the suction port  4 . A plurality of wheels  6  are provided at lower positions of the main body  3 . The wheels  6  are rolled along the floor surface, whereby the main body  3  is moved along the floor surface.  
      The electric vacuum cleaner  1  is adapted to receive a cyclonic dust collecting apparatus  7  which swirls the air sucked from the suction port  4  to separate the dust from the air by a centrifugal force and capture the dust. A fan accommodating chamber  8  in which the electric fan  2  is accommodated is defined in a rear portion of the main body  3 , and a dust collecting chamber  9  in which the dust collecting apparatus  7  is accommodated is defined in a front portion of the main body  3 . The electric fan  2  is disposed in a right side space occupying about two thirds of the fan accommodating chamber  8 , and a cord accommodating portion  11  in which an electric cord  10  for power supply to the electric vacuum cleaner  1  from the outside is accommodated is defined in a left side space occupying about one third of the fan accommodating chamber  8 . In the cord accommodating portion  11 , a cord reel  12  is disposed rotatably about a laterally extending rotation shaft  12 A. When the electric vacuum cleaner  1  is not in use, the electric cord  10  is wound around the cord reel  12  in the cord accommodating portion  11 .  
      The dust collecting chamber  9  has a top opening, which is covered with a dust cover  13 . A front wall  9 A defining a front face of the dust collecting chamber  9  has a generally round opening  14  which communicates with the suction port  4 . The opening  14  is oriented slightly upward with respect to a vertical plane, i.e., inclined forward toward the upper side.  
      The dust collecting apparatus  7  has a generally round air inlet  15  formed in a front face thereof, and a tubular inlet pipe  16  projecting forward from the inlet  15 . A front edge of the inlet pipe  16  is inclined forward toward the upper side as corresponding to the inclination of the opening  14 . The dust collecting apparatus  7  is inserted into the dust collecting chamber  9  from the upper side through the top opening with the dust cover  13  being opened. Since the opening  14  and the front edge of the inlet pipe  16  are inclined with respect to the vertical plane as described above, interference between a peripheral edge of the opening  14  and the inlet pipe  16  is prevented even if the dust collecting apparatus  7  is inserted vertically downward into the dust collecting chamber  9 . A generally annular packing  17  is attached to the peripheral edge of the opening  14 . With the dust collecting apparatus  7  accommodated in the dust collecting chamber  9 , the front edge of the inlet pipe  16  is pressed against the packing  17 , so that a gap between the opening  14  and the front edge of the inlet pipe  16  is sealed.  
      The dust collecting apparatus  7  includes a hollow casing  18  of a resin, for example, in which air is swirled, a filter  20  which permits passage of air to be discharged from an air outlet port  19  provided in a rear face of the casing  18  to capture dust entrained in the air, and a filter holder  18 B which surrounds the outer periphery of the filter  20  to hold the filter  20 . The filter  20  is composed of, for example, a urethane-containing material.  
      The inlet  15  is provided in a front face of the casing  18 , and the inlet pipe  16  projects forward from the inlet  15 . A cyclonic flow path  21  is defined by a partition wall in the casing  18 . More specifically, the air entering the casing  18  from the inlet  15  is swirled clockwise about a swirl axis  22  (see  FIG. 2 ) as seen from the front side along the cyclonic flow path  21 . A terminal end of the cyclonic flow path  21  communicates with a dust collecting portion  23  spreading immediately upstream of the air outlet port  19  (just in front of the air outlet port  19 ).  
      The dust entrained in the air flowing into the casing  18  from the inlet  15  passes through an outer portion of the cyclonic flow path  21  (a radially outward portion about the swirl axis  22 ) by a centrifugal force when the air is swirled along the cyclonic flow path  21 . A generally cylindrical filter  24  (see  FIG. 2 ) is disposed along the swirl axis  22  in the casing  18 . The filter  24  is, for example, a mesh filter prepared by combining metal wires into mesh. A rear end of the filter  24  faces toward a portion of the dust collecting portion  23  immediately upstream of the air outlet port  19 . With this arrangement, the dust entrained in the air swirled along the cyclonic flow path  21  is swirled in the outer portion of the cyclonic flow path  21  and, therefore, guided into the dust collecting portion  23  without passing through the filter  24 . A part of the air (from which the dust is separated) swirled in an inner portion of the cyclonic flow path  21  (adjacent to the swirl axis  22 ) passes through the filter  24 , and flows inside the filter  24  to be guided to the portion immediately upstream of the air outlet port  19 . Therefore, the dust entrained in the air flowing into the casing  18  from the inlet  15  is separated by the centrifugal force and captured by the dust collecting portion  23 , while the air from which the dust is separated is guided through the filter  24  toward the air outlet port  19 . Thus, the dust can be advantageously captured.  
       FIG. 3  is a perspective view of the filter holder  18 B as obliquely seen from a front upper side.  FIG. 4  is a perspective view illustrating the filter holder  18 B and the filter  20  held by the filter holder  18 B partly in section taken along a horizontal plane.  
      Referring to  FIGS. 3 and 4 , the filter holder  18 B includes a rear plate  25  of a generally rectangular shape and a side plate frame  26  projecting forward from an outer peripheral edge of the rear plate  25 , and the rear plate  25  and the side plate frame  26  are integrally formed of, for example, a resin. The filter  20  is fitted in the filter holder  18 B with its outer peripheral surface fitted along an inner peripheral surface of the side plate frame  26 . A front surface of the filter  20  is substantially flush with a front edge of the side plate frame  26  with the filter  20  fitted in the filter holder  18 B. The side plate frame  26  has a positioning projection  27  provided on the inner peripheral surface thereof (in a lower left corner thereof). The filter  20  has a recess  28  in association with the positioning projection  27  (in a lower left corner thereof). With the positioning projection  27  fitted in the recess  28 , the filter  20  can be fitted in the filter holder  18 B in a correct orientation with respect to lateral, vertical and anteroposterior directions.  
      The side plate frame  26  has attachment members  29  provided at laterally opposite ends of a lower edge thereof for pivotally attaching the filter holder  18 B to the casing  18 . The side plate frame  26  further has an operation portion  30  projecting from a transversely middle portion of an upper edge thereof. When the dust collected in the dust collecting apparatus  7  (in the casing  18 ) is to be removed, the dust cover  13  is opened, then the dust collecting apparatus  7  is taken out of the dust collecting chamber  9 , and the casing  18  is opened by pulling the operation portion  30  rearward to pivot the filter holder  18 B about the attachment members  29 . In this state, the dust can be easily removed from the casing  18 . Further, the filter  20  is detached from the filter holder  18 B to remove dust adhering to the filter  20 .  
      The rear plate  25  of the filter holder  18 B has a generally rectangular opening  31 . A plurality of vent holes for passing air discharged from the air outlet port  19  through the filter  20  are defined in the opening  31  by a plurality of ribs extending vertically (vertical ribs  32 A) and a plurality of ribs extending transversely (transverse ribs  32 B). Front surfaces of the respective transverse ribs  32 B are located forwardly of front surfaces of the respective vertical ribs  32 A. A frame rib (peripheral rib  32 C) is provided on a peripheral edge of the opening  31  as projecting forward. A front surface of the peripheral rib  32 C is located forwardly of the front surfaces of the respective transverse ribs  32 B. With this arrangement, the front surfaces of the respective transverse ribs  32 B abut against a rear surface of the filter  20 , and the peripheral rib  32 C intrudes into a peripheral portion of the rear surface of the filter  20  with the filter  20  fitted in the filter holder  18 B. In this state, the rear surface of the filter  20  is spaced a predetermined distance (e.g., about 6 mm) from the vertical ribs  32 A.  
      Referring again to  FIGS. 1 and 2 , when the dust collecting apparatus  7  is inserted in the dust collecting chamber  9 , a rear surface of the filter holder  18 B abuts against a rear wall  9 B defining a rear face of the dust colleting chamber  9 . The rear wall  9 B has a generally rectangular opening  33  formed in a portion thereof extending rightward from a center portion thereof (opposed to a space in which the electric fan  2  is disposed in the fan accommodating chamber  8 ) as having a size smaller than the area of the filter  20  (air outlet port  19 ). The dust collecting chamber  9  and the fan accommodating chamber  8  communicate with each other through the opening  33 . The opening  33  is opposed to a suction port  2 A of the electric fan  2  disposed in the fan accommodating chamber  8 . The opening  33  is covered with a filter  34  having a pleat structure formed by folding filter paper into a bellows shape.  
      In this embodiment, the dust collecting apparatus  7  (casing  18 ) has the greatest possible size (the dust collecting apparatus  7  occupies a wider area of the dust collecting chamber  9  from the left side to the right side) to ensure that the air sucked from the suction port  4  of the main body  3  can be properly swirled for improvement of the dust collecting efficiency. Further, the air outlet port  19  has a great size (the air outlet port  19  is provided in the entire rear surface of the dust collecting apparatus  7 ) to ensure that the air from the dust collecting apparatus  7  can be properly discharged. Since the air outlet port  19  has a great size, the size of the filter  20  covering the air outlet port  19  can be increased. Therefore, clogging of the filter  20  can be suppressed.  
      On the other hand, the fan accommodating chamber  8  which is located behind the dust collecting chamber  9  with the intervention of the rear wall  9 B is required to have a space for accommodating components other than the electric fan  2  (e.g., the cord accommodating portion  11  in which the cord reel  12  is disposed). Therefore, the opening  33  formed in the rear wall  9 B has a smaller size than the air outlet port  19 . In this case, a portion of the air outlet port  19  opposed to the opening  33  ensures proper air flow to the opening  33  through the filter  20 , but the other portion of the air outlet port  19  not opposed to the opening  33  is liable to prohibit the proper air flow.  
      In this embodiment, the rear surface of the filter  20  is spaced from the vertical ribs  32 A, so that a guide passage  35  is defined for guiding the air discharged through the filter  20  from the portion of the air outlet port  19  not opposed to the opening  33  toward the opening  33 . Therefore, the air flow from the portion of the air outlet port  19  not opposed to the opening  33  can be ensured by the guide passage  35 , thereby suppressing the reduction of the suction force to improve the dust collecting efficiency.  
      In particular, the rear surface of the filter holder  18 B abuts against the rear wall  9 B, so that the dust collecting apparatus  7  can be firmly fixed in the dust collecting chamber  9 . Further, the guide passage  35  can be defined by the space between the vertical ribs  32 A and the filter  20 .  
      Since the peripheral rib  32 C of the filter holder  18 B intrudes into the rear surface of the filter  20 , there is no gap between the peripheral portion of the filter  20  and the filter holder  18 B. Therefore, the peripheral rib  32 C serves as a barrier to prevent the dust from leaking from the dust collecting apparatus  7  between the peripheral portion of the filter  20  and the filter holder  18 B.  
      In this embodiment, the vertical ribs  32 A and the transverse ribs  32 B which serve as a filter cover are formed integrally with the filter holder  18 B. Thus, the number of components can be reduced, thereby reducing the production costs.  
      In this embodiment, a portion (left portion) of the dust collecting portion  23  not opposed to the opening  33  is narrower than a portion (right portion) of the dust collecting portion  23  opposed to the opening  33 . The space of the dust collecting portion  23  has a cross section which progressively decreases toward the portion of the dust collecting portion  23  not opposed to the opening  33  (see  FIG. 2 ). In general, the air swirled in the dust collecting apparatus  7  tends to flow toward a narrower space. With the aforesaid arrangement, the air can be positively guided toward the portion of the air outlet port  19  not opposed to the opening  33  in which the air communication is poorer, so that the air can be discharged from the entire air outlet port  19  including not only the portion of the air outlet port  19  opposed to the opening  33  but also the portion of the air outlet port  19  not opposed to the opening  33 . Thus, the collected dust is also guided toward the narrower space. Therefore, the dust is first gradually accumulated in the space not opposed to the opening  33 , and finally captured by the entire filter  20 . Thus, the dust collecting efficiency is improved.  
      The construction of the dust collecting apparatus  7  is not limited to the construction described above, but the dust collecting apparatus  7  may have the same construction as a dust collecting apparatus  107  according to a second embodiment to be described in detail with reference to FIGS.  8  to  10 .  
       FIG. 5  is a sectional view of an electric vacuum cleaner  101  according to the second embodiment of the present invention, the sectional view being taken along an anteroposterior vertical plane and seen from a right side.  FIG. 6  is a plan view of the electric vacuum cleaner  101  with its dust cover  113  removed. A left side and a right side in  FIG. 5  are respectively defined as a front side and a rear side of the electric vacuum cleaner  101 . An upper side and a lower side in  FIG. 6  are respectively defined as a left side and a right side of the electric vacuum cleaner  101 .  
      Referring to  FIGS. 5 and 6 , the electric vacuum cleaner  101  includes a main body  103  having an electric fan  102 , and one end of a connection hose (not shown) is inserted into a suction port  104  provided at a front end of the main body  103 . The connection hose is an elongated tubular member with at least a part thereof having a bellows shape. Though not shown, a suction member is attached to the other end of the connection hose. When a cleaning operation is performed, the suction member is moved along a floor surface with the electric fan  102  in the main body  103  being driven. Thus, dust on the floor surface is sucked together with air from the suction member. The air sucked from the suction member flows through the connection hose into the main body  103  from the suction port  104 . A plurality of wheels  106  are provided at lower positions of the main body  103 . The wheels  106  are rolled along the floor surface, whereby the main body  103  is moved along the floor surface.  
      One feature of the electric vacuum cleaner  101  is that a commercially available disposable filter  40  (not shown in  FIGS. 5 and 6 ) such as a paper pack and a cyclonic dust collecting apparatus  107  (not shown in  FIGS. 5 and 6 ) which is capable of swirling the air sucked from the suction port  104  to separate dust from the air by a centrifugal force and capture the dust are selectively mounted in the electric vacuum cleaner  101 . With this arrangement, a user is permitted to mount either the dust collecting apparatus  107  or the disposable filter  40  according to user&#39;s preference. Therefore, the electric vacuum cleaner  101  is more convenient to use.  
      A fan accommodating chamber  108  in which the electric fan  102  is accommodated is defined in a rear portion of the main body  103 , and a dust collecting chamber  109  in which the dust collecting apparatus  107  or the disposable filter  40  is accommodated is defined in a front portion of the main body  103 . When the electric vacuum cleaner  101  is not in use, an electric cord  110  for power supply to the electric vacuum cleaner  101  from the outside is accommodated in a wound state in a left side portion of the fan accommodating chamber  108 .  
      The dust collecting chamber  109  has a top opening, which is covered with a dust cover  113 . The dust cover  113  is attached pivotally to the main body  103  at its rear edge. The dust collecting chamber  109  is covered and uncovered by pivoting the dust cover  113  (in  FIG. 5 , the dust cover  113  is opened). A front wall  109 A defining a front face of the dust collecting chamber  109  has a generally round opening  114  which communicates with the suction port  104 . The opening  114  is oriented slightly upward with respect to a vertical plane, i.e., inclined forward toward the upper side. A generally annular packing  117  is attached to a peripheral edge of the opening  114 .  
      An engagement member  41  for fixing the disposable filter  40  when the disposable filter  40  is accommodated in the dust collecting chamber  109  is provided on an upper front portion of the dust collecting chamber  109  (at a front edge of the top opening) pivotally about a laterally extending pivot shaft (not shown). The engagement member  41  includes a laterally extending base  42 , a pair of engagement projections  43  projecting rearward from laterally opposite ends of the base  42 , and an operation portion  44  projecting upward from a transversely middle portion of the base  42 , and these portions  42 ,  43 ,  44  are integrally formed. The engagement member  41  is biased clockwise as seen in  FIG. 5  by a resilient member such as a spring. Where the disposable filter  40  is not fixed, the engagement member  41  is kept at a position (initial position) shown in  FIG. 5 . Claws  43 A for hooking an upper edge of the disposable filter  40  respectively project from lower surfaces of the engagement projections  43 .  
       FIG. 7  is a sectional view of the electric vacuum cleaner  101  taken along the anteroposterior vertical plane and seen from the right side with the disposable filter  40  mounted therein.  
      As shown in  FIG. 7 , the disposable filter  40  includes a generally rectangular cardboard base  40 A and a paper bag filter  40 B having an open portion fixed to a rear face of the cardboard base  40 A. The cardboard base  40 A has a generally round inlet  45  provided in a center portion thereof as corresponding to the opening  114 . A rear side of the inlet  45  is covered with the paper filter  40 B.  
      Referring to FIGS.  5  to  7 , a pair of guide members  46  for guiding laterally opposite edges of the cardboard base  40 A when the disposable filter  40  is mounted in and demounted from the dust collecting chamber  109  project from laterally opposite edges of the front wall  109 A of the dust collecting chamber  109  as extending vertically. A pair of stoppers  47  for preventing rearward displacement of a lower edge of the cardboard base  40 A of the disposable filter  40  when the disposable filter  40  is mounted in the dust collecting chamber  109  project from a front edge of a bottom of the dust collecting chamber  109 .  
      When the disposable filter  40  is to be accommodated in the dust collecting chamber  109 , the pair of engagement projections  43  are first retracted from a disposable filter (cardboard base) insertion path by pulling the operation portion  44  forward and pivoting the engagement member  41  counterclockwise as seen in  FIG. 5 . In this state, the disposable filter  40  is inserted into the dust collecting chamber  109  from the upper side through the top opening, and the laterally opposite edges of the cardboard base  40 A are slid downward along the pair of guide members  46 . After the lower edge of the cardboard base  40 A is thus brought into abutment against a bottom portion of the dust collecting chamber  109  in front of the pair of stoppers  47 , a force applied to the engagement member  41  is released, and the engagement member  41  is pivoted toward the initial position (clockwise as seen in  FIG. 5 ), whereby the claws  43 A of the respective engagement projections  43  are engaged with an upper edge of the cardboard base  40 A. As a result, the cardboard base  40 A is pressed against the packing  117  by a force applied forward by the engagement projections  43 . Thus, a front peripheral edge of the inlet  45  of the cardboard base  40 A is pressed against the packing  117 , whereby a gap between the opening  114  and the inlet  45  is sealed.  
      When the electric vacuum cleaner  101  is driven (the electric fan  102  is driven) with the disposable filter  40  mounted therein, the air sucked from the suction member flows into the main body  103  through the connection hose and the suction port  104  thereby to be introduced into the paper filter  40 B of the disposable filter  40  from the opening  114  through the inlet  45 . When the air introduced into the paper filter  40 B passes through the paper filter  40 B, the dust entrained in the air is captured by the paper filter  40 B.  
       FIG. 8  is a front view of the dust collecting apparatus  107  to be mounted in the electric vacuum cleaner  101 .  FIG. 9  is a right side view of the dust collecting apparatus  107 .  
      Referring to  FIGS. 8 and 9 , a generally round air inlet  50  through which air is introduced into the dust collecting apparatus  107  is provided in a front face of the dust collecting apparatus  107 , and a tubular inlet pipe  51  projects forward from the inlet  50 . A front edge of the inlet pipe  51  is inclined forward toward the upper side as corresponding to the inclination of the opening  114 .  
      The dust collecting apparatus  107  includes a hollow casing  52  in which the air is swirled, a filter  54  which permits passage of air to be discharged from an air outlet port  53  provided in a rear face of the casing  52  and captures dust entrained in the air, and a filter holder  55  which surrounds the outer periphery of the filter  54  to hold the filter  54 . The filter  54  is composed of, for example, a urethane-containing material. Attachment members  56  for pivotally attaching the filter holder  55  to the casing  52  respectively project downward from laterally opposite portions of a lower surface of the filter holder  55 . Fixing members  57  for pivotally fixing the attachment members  56  of the filter holder  55  respectively project downward from laterally opposite ends of a rear lower edge of the casing  52 .  
      In this embodiment, it is possible to hold tissue paper between the casing  52  and the filter holder  55  (immediately upstream of the filter  54 ) and press a peripheral portion of the tissue paper held between the casing  52  and the filter holder  55  by a metal press frame  58  extending along the outer periphery of the casing  52 . The press frame  58  has a left end portion bent rightward and a right end portion bent leftward. The left and right end portions of the press frame  58  respectively serve as pivot shafts  63  of the press frame  58 . The press frame  58  is pivotally attached to the casing  52  and the filter holder  55  with its left end portion (left pivot shaft  63 ) pivotally attached to the left attachment member  56  and the left fixing member  57  and with its right end portion (right pivot shaft  63 ) pivotally attached to the right attachment member  56  and the right fixing member  57 .  
       FIG. 10  is a sectional view of a portion A in  FIG. 8 .  
      As shown in  FIG. 10 , the attachment members  56  provided on the filter holder  55  each include a pair of clamp portions  56 A,  56 B spaced a predetermined distance in laterally opposed relation. The clamp portions  56 A,  56 B respectively have generally cylindrical pivot shafts  59  which project toward each other coaxially from lower portions of opposed surfaces thereof.  
      The fixing members  57  provided on the casing  52  each include an insertion portion  57 A inserted between the pair of clamp portions  56 A and  56 B of the attachment member  56 , and a through-hole portion  57 B through which the pivot shaft  63  of the press frame  58  extends. The insertion portion  57 A has a through-hole  60  laterally extending through a lower end portion thereof. The insertion portion  57 A is inserted between the pair of clamp portions  56 A and  56 B of the attachment member  56 , whereby the pivot shaft  59  of the left clamp portion  56 A is inserted into the through-hole  60  from the left side and the pivot shaft  59  of the right clamp portion  56 B is inserted into the through-hole  60  from the right side. Thus, the filter holder  55  can be pivotally attached to the casing  52 .  
      The through-hole portion  57 B has a through-hole  61  laterally extending through a lower portion thereof. Of the pair of clamp portions  56 A,  56 B, the clamp portion  56 A adjacent to the through-hole portion  57 B has an insertion hole  62  opening toward the through-hole portion  57 B. The pivot shaft  63  of the press frame  58  extends through the through-hole  61  with a distal end thereof inserted in the insertion hole  62 . Thus, the pivot shaft  63  is pivotally held by the through-hole  61  and the insertion hole  62 . With this attaching arrangement, the pivot shaft  63  is engaged with both the casing  52  and the filter holder  55 . Therefore, the pivot shaft  63  is hardly disengaged, so that a robust structure can be provided.  
      Since the pivot shaft  63  is inserted through the through-hole  61  into the insertion hole  62 , the pivot shaft attaching operation can be easily performed as compared with a case in which the pivot shaft  63  is attached with the use of a fixing member such as an E-ring.  
      Further, the end portion of the pivot shaft  63  is inserted in the insertion hole  62  and, therefore, even if the end portion is formed with burrs, the burrs are not exposed outside. This makes the attaching arrangement safer.  
      While the attaching arrangement associated with the left attachment member  56  and the left fixing member  57  has been described with reference to  FIG. 10 , the attaching arrangement associated with the right attachment member  56  and the right fixing member  57  has substantially the same structure.  
      When the dust collected in the dust collecting apparatus  107  (in the casing  52 ) is to be removed, the dust cover  113  is opened, then the dust collecting apparatus  107  is taken out of the dust collecting chamber  109 , and the casing  52  is opened by pivoting the filter holder  55  about the pivot shafts  59  of the attachment members  56 . In this state, the dust can be easily removed from the casing  52 . Further, the filter  54  is detached from the filter holder  55  to remove dust adhering to the filter  54 .  
      Where the dust collecting apparatus  107  is used with the tissue paper held between the casing  52  and the filter holder  55  (immediately upstream of the filter  54 ) and with the peripheral portion of the tissue paper pressed by the press frame  58 , the air flowing through the casing  52  to the air outlet port  53  passes through the tissue paper before passing through the filter  54 . Therefore, the dust entrained in the air is mostly captured by the tissue paper. In this case, when the dust collected in the dust collecting apparatus  107  (in the casing  52 ) is to be removed, the casing  52  is opened by pivoting the filter holder  52 . Thus, the dust in the casing  52  can be easily removed. Further, the peripheral portion of the tissue paper is released by pivoting the press frame  58 . Thus, the tissue paper can be removed to be discarded. With this arrangement, the dust hardly adheres to the filter  54 , so that the need for removing the dust from the filter  54  is obviated to improve the convenience.  
      Referring again to  FIGS. 8 and 9 , the casing  52  includes a front member  52 A defining a front portion thereof and a rear member  52 B defining a rear portion thereof. The front member  52 A and the rear member  52 B are bonded (e.g., fuse-bonded) to each other. More specifically, the front member  52 A and the rear member  52 B respectively have a bonding rib  64 A projecting from the entire rear outer peripheral edge of the front member  52 A and a bonding rib  64 B projecting from the entire front outer peripheral edge of the rear member  52 B for bonding the front member  52 A and the rear member  52 B to each other. A predetermined fuse-bonding process is performed with the bonding ribs  64 A,  64 B in abutment with each other. Thus, the bonding ribs  64 A,  64 B are fuse-bonded to each other to combine the front member  52 A and the rear member  52 B.  
      In this embodiment, laterally opposite lower edge portions of the bonding rib  64 A of the front member  52 A are extended downward to define a pair of legs  65 . With this arrangement, when the dust collecting apparatus  107  is demounted from the electric vacuum cleaner  101  and placed on a floor surface for cleaning the dust collecting apparatus  107 , the dust collecting apparatus  107  can be held upright by the pair of legs  65  and other portions of the casing  52  (the attachment members  56  and the fixing members  57 ). Therefore, the dust collecting apparatus  107  is prevented from falling down to scatter the dust out of the dust collecting apparatus  107 . Thus, the removal of the dust from the dust collecting apparatus  107  is facilitated.  
      In this embodiment, lower end portions of the respective legs  65  are extended to the same level as the lowermost ends of the other portions (the attachment members  56  and the fixing members  57  of the casing  52 ), whereby the inlet  50  of the dust collecting apparatus  107  is oriented generally horizontally with the dust collecting apparatus  107  held upright by the pair of legs  65 . With this arrangement, the dust is prevented from being scattered out of the dust collecting apparatus  107  from the inlet  50  with the dust collecting apparatus  107  held upright by the pair of legs  65 . Therefore, the removal of the dust from the dust collecting apparatus  107  is further facilitated. With the dust collecting apparatus  107  held upright by the pair of legs  65 , the inlet  50  of the dust collecting apparatus  107  is not necessarily required to be oriented generally horizontally, but may be oriented upward (or obliquely upward).  
      In this embodiment, a cleaning device  66  (e.g., a brush) to be used for cleaning the dust collecting apparatus  107  is retained on rear faces of the legs  65 . With this arrangement, the cleaning device  66  is not retained on a wall of the dust collecting chamber  109 , but retained on the dust collecting apparatus  107 . Therefore, when the disposable filter  40  is mounted in the dust collecting apparatus  107 , damage to the paper filter  40 B of the disposable filter  40  is prevented which may otherwise occur when the paper filter  40 B is brought into contact with the cleaning device  66  retained on the wall of the dust collecting chamber  109 .  
      Since parts of the bonding ribs  64 A are extended to define the pair of legs  65 , simple structures can be provided for keeping the dust collecting apparatus  107  upright and for retaining the cleaning device  66  on the dust collecting apparatus  107 , as compared with a case in which the legs are provided as separate members.  
      The inlet  50  is provided in a front face of the casing  52  (front member  52 A), and the inlet pipe  51  projects forward from the inlet  50 . A cyclonic flow path  67  is defined by a partition wall in the casing  52 . More specifically, the air entering the casing  52  from the inlet  50  is swirled clockwise about an anteroposteriorly extending swirl axis  68  as seen from the front side along the cyclonic flow path  67  and indicated by an arrow in  FIG. 8 . A terminal end of the cyclonic flow path  67  communicates with a dust collecting portion  69  spreading immediately upstream of the air outlet port  53  (in front of the air outlet port  53 ).  
      The dust entrained in the air flowing into the casing  52  from the inlet  50  passes through an outer portion of the cyclonic flow path  67  (a radially outward portion about the swirl axis  68 ) by a centrifugal force when the air is swirled along the cyclonic flow path  67 . A generally cylindrical filter  70  is disposed along the swirl axis  68  in the casing  52 . The filter  70  is, for example, a mesh filter prepared by combining metal wires into mesh. A rear end of the filter  70  faces toward a portion of the dust collecting portion  69  immediately upstream of the air outlet port  53 . With this arrangement, the dust entrained in the air swirled along the cyclonic flow path  67  is swirled in the outer portion of the cyclonic flow path  67  and, therefore, guided into the dust collecting portion  69  without passing through the filter  70 . A part of the air (from which the dust is separated) swirled in an inner portion of the cyclonic flow path  67  (adjacent to the swirl axis  68 ) passes through the filter  70 , and flows inside the filter  70  to be guided to the portion immediately upstream of the air outlet port  53 . Therefore, the dust entrained in the air flowing into the casing  52  from the inlet  50  is separated by the centrifugal force and captured by the dust collecting portion  69 , while the air from which the dust is separated is guided through the filter  70  toward the air outlet port  53 . Thus, the dust can be advantageously captured.  
      A cover  71  which covers a front portion of the filter  70  is openably attached to the front face of the casing  52  (front member  52 A). With the cover  71  being opened to uncover the front portion of the filter  70 , the filter  70  is drawn forward for cleaning thereof. The casing  52  (front member  52 A) has a rib  72  projecting forward from the front face thereof on a lateral side (right side) of the inlet  50 . The rib  72  vertically extends (in the direction of the insertion of the dust collecting apparatus  107 ), and its distal edge extends to the vicinity of the front edge of the inlet pipe  51 . A handle  73  to be held when the dust collecting apparatus  107  is mounted and demounted is provided on an upper side of the casing  52  as extending anteroposteriorly.  
       FIG. 11  is a sectional view of the electric vacuum cleaner  101  taken along the anteroposterior vertical plane and seen from the right side with the dust collecting apparatus  107  to be mounted therein.  FIG. 12  is a sectional view of the electric vacuum cleaner  101  taken along the anteroposterior vertical plane and seen from the right side with the dust collecting apparatus  107  mounted therein.  
      Referring to  FIGS. 11 and 12 , the dust collecting apparatus  107  is inserted into the dust collecting chamber  109  from the upper side through the top opening with the dust cover  113  being opened. That is, the dust collecting apparatus  107  is slid vertically downward (diametrically of the inlet  50 ) with respect to the dust collecting chamber  109  thereby to be accommodated in the dust collecting chamber  109 . A distance between the pair of engagement projections  43  of the engagement member  41  is greater than the outer diameter of the inlet pipe  51  of the dust collecting apparatus  107 . When the dust collecting apparatus  107  is inserted into the dust collecting chamber  109 , the inlet pipe  51  is passed between the pair of engagement projections  43  as indicated by a one-dot-and-dash line in  FIG. 11 . With this arrangement, when the disposable filter  40  is accommodated in the dust collecting chamber  109 , the cardboard base  40 A of the disposable filter  40  is fixed by the pair of engagement projections  43 . When the dust collecting apparatus  107  is accommodated in the dust collecting chamber  109 , the inlet pipe  51  of the dust collecting apparatus  107  is prevented from interfering with the pair of engagement projections  43  which are adapted to fix the cardboard base  40 A of the disposable filter  40 . Therefore, either the dust collecting apparatus  107  or the disposable filter  40  can be properly mounted.  
      With the dust collecting apparatus  107  mounted in the dust collecting chamber  109 , the gap between the opening  114  and the front edge of the inlet pipe  51  is sealed, as shown in  FIG. 12 , by pressing the front edge of the inlet pipe  51  against the packing  117 . As described above, the opening  114  is oriented slightly upward with respect to the vertical plane, i.e., inclined forward toward the upper side, and the front edge of the inlet pipe  51  is also inclined forward toward the upper side as corresponding to the inclination of the opening  114 . Therefore, even if the dust collecting apparatus  107  is inserted vertically downward into the dust collecting chamber  109 , the interference between the peripheral edge of the opening  114  and the inlet pipe  51  can be prevented.  
      FIGS.  13 ( a ) and  13 ( b ) are diagrams respectively illustrating states of the packing  117  deformed when the dust collecting apparatus  107  is mounted and when the disposable filter  40  is mounted. Particularly,  FIG. 13 ( a ) illustrates a portion B in  FIG. 7  on an enlarged scale to show the packing  117  deformed when the disposable filter  40  is mounted, and  FIG. 13 ( b ) illustrates a portion C in  FIG. 12  on an enlarged scale to show the packing  117  deformed when the dust collecting apparatus  107  is mounted.  
      The packing  117  is composed of an elastic material such as rubber, and includes a cylindrical base  117 A fitted in the opening  114 , a cylindrical portion  117 B projecting from a rear face of the base  117 A, an annular resiliently deformable portion  117 C projecting radially outward from a rear edge of the cylindrical portion  117 B, and an annular projection  117 D projecting rearward from a junction between the cylindrical portion  117 B and the annular resiliently deformable portion  117 C, and these parts  117 A,  117 B,  117 C,  117 D are integrally formed. The annular projection  117 D has a convexly curved cross section (generally arcuate cross section).  
      When the disposable filter  40  is mounted, as shown in  FIG. 13 ( a ), the annular projection  117 D bites the inner periphery of the inlet  45  of the disposable filter  40 , and the front surface of the cardboard base  40 A (the peripheral edge of the inlet  45 ) abuts against the entire rear surface of the annular resiliently deformable portion  117 C, whereby the annular resiliently deformable portion  117 C is pressed forward to be resiliently deformed. On the other hand, the inlet pipe  51  of the dust collecting apparatus  107  has substantially the same size as the inlet  45  of the disposable filter  40  or a greater size than the inlet  45  of the disposable filter  40 . When the dust collecting apparatus  107  is mounted, as shown in  FIG. 13 ( b ), the front edge of the inlet pipe  51  abuts against the rear surface of the annular resiliently deformable portion  117 C, whereby the annular resiliently deformable portion  117 C is pressed forward to be resiliently deformed. With this arrangement, when either the dust collecting apparatus  107  or the disposable filter  40  is mounted, the peripheral edge of the inlet  45  or the front edge of the inlet pipe  51  is pressed with a sufficient resilient force by the packing  117 . Therefore, the air is advantageously prevented from leaking from the peripheral edge of the inlet  45  or the front edge of the inlet pipe  51 , thereby improving the dust collecting efficiency.  
      The annular projection  117 D has a convexly curved cross-section and, therefore, even if the peripheral edge of the inlet  45  or the front edge of the inlet pipe  51  interferes with the annular projection  117 D when the dust collecting apparatus  107  or the disposable filter  40  is slid into the dust collecting chamber  109 , the annular projection  117 D rides over the annular projection  117 D along the convexly curved surface. Therefore, the dust collecting apparatus  107  or the disposable filter  40  can be properly mounted.  
      FIGS.  14 ( a ) and  14 ( b ) are diagrams illustrating a variation of the packing  117 . Particularly,  FIG. 14 ( a ) is a rear view of a packing  217  according to the variation, and  FIG. 14 ( b ) is a sectional view of the packing  217  as seen along a line G-G in  FIG. 14 ( a ).  
      Referring to FIGS.  14 ( a ) and  14 ( b ), the packing  217  according to this variation is composed of an elastic material such as rubber. Like the packing  117  according to the aforesaid embodiment, the packing  217  includes a cylindrical base  217 A fitted in the opening  114 , a cylindrical portion  217 B projecting from a rear face of the base  217 A, an annular resiliently deformable portion  217 C projecting radially outward from a rear edge of the cylindrical portion  217 B, and an annular projection  217 D projecting rearward from a junction between the cylindrical portion  217 B and the annular resiliently deformable portion  217 C, and these parts  217 A,  217 B,  217 C,  217 D are integrally formed. The annular projection  217 D has a convexly curved cross section (generally arcuate cross section).  
      A feature of the packing  217  according to this variation is that an upper edge portion of the annular resiliently deformable portion  217 C projects further outward (upward) than the other portion of the annular resiliently deformable portion  217 C to define a guide portion  217 E. The guide portion  217 E is curved to be inclined forward toward the upper side.  
      This arrangement provides the same effects as the packing  117  according to the aforesaid embodiment. In addition, when the dust collecting apparatus  107  or the disposable filter  40  is mounted, the front edge of the inlet pipe  51  of the dust collecting apparatus  107  inserted from the upper side or the cardboard base  40 A of the disposable filter  40  can be slid along the curved rear surface of the guide portion  217 E thereby to be properly guided toward the annular resiliently deformable portion  217 C. Therefore, either the dust collecting apparatus  107  or the disposable filter  40  can be properly mounted.  
       FIG. 15  is a plan view of an electric vacuum cleaner  101 A according to a first variation of the second embodiment with its dust cover  113  removed.  
      The electric vacuum cleaner  101 A is characterized in that the pair of guide members  46  are used instead of the engagement member  41  of the second embodiment as the fixing member for fixing the cardboard base  40 A of the disposable filter  40 . Therefore, the electric vacuum cleaner  101 A has substantially the same construction as the second embodiment, except that the engagement member  41  is omitted and the pair of guide members  46  each have a modified shape. Hence, like components will be denoted by like reference characters, and no explanation will be given thereto.  
      Referring to  FIG. 15 , rear end portions of the respective guide members  46  (a left guide member  46 L and a right guide member  46 R) projecting rearward from the laterally opposite edges of the front wall  109 A of the dust collecting chamber  109  are bent generally perpendicularly toward each other. That is, the left guide member  46 L has a rear end portion  48 L bent rightward, and the right guide member  46 R has a rear end portion  48 R bent leftward.  
      When the disposable filter  40  is to be accommodated in the dust collecting chamber  109 , the disposable filter  40  is inserted into the dust collecting chamber  109  from the upper side through the top opening, and the laterally opposite edges of the cardboard base  40 A are slid downward along the pair of guide members  46  (along front surfaces of the respective bent portions  48 L,  48 R). After the lower edge of the cardboard base  40 A is thus brought into abutment against the bottom portion of the dust collecting chamber  109  in front of the pair of stoppers  47 , the dust cover  113  is closed. The dust cover  113  has an engagement member (not shown) provided on an interior surface thereof (which faces toward the dust collecting chamber  109  when the dust cover  113  is closed) for fixing the upper edge of the cardboard base  40 A of the disposable filter  40 . When the dust cover  113  is closed, the upper edge of the cardboard base  40 A of the disposable filter  40  is pressed forward by the engagement member. With the dust cover  113  thus closed, the cardboard base  40 A is pressed against the packing  117  by a force applied forward by the engagement member. Thus, the peripheral edge of the inlet  45  provided in the front face of the cardboard base  40 A is pressed against the packing  117 , whereby the gap between the opening  114  and the inlet  45  is sealed.  
      In this variation, a distance between distal ends of the respective bent portions  48 L and  48 R is greater than the outer diameter of the inlet pipe  51  of the dust collecting apparatus  107 , so that the inlet pipe  51  passes between the bent portions  48 L and  48 R when the dust collecting apparatus  107  is inserted into the dust collecting chamber  109 . With this arrangement, when the disposable filter  40  is accommodated in the dust collecting chamber  109 , the disposable filter  40  can be fixed by the pair of bent portions  48 L,  48 R. Further, when the dust collecting apparatus  107  is accommodated in the dust collecting chamber  109 , the inlet pipe  51  of the dust collecting apparatus  107  is prevented from interfering with the pair of bent portions  48 L,  48 R which are adapted to fix the cardboard base  40 A of the disposable filter  40 . Therefore, either the dust collecting apparatus  107  or the disposable filter  40  can be properly mounted.  
       FIG. 16  is a sectional view of an electric vacuum cleaner  101 B according to a second variation of the second embodiment with neither the dust collecting apparatus  107  nor the disposable filter  40  mounted therein, the sectional view being taken along an anteroposterior vertical plane and seen from a right side.  FIG. 17  is a sectional view of a dust cover  113  as seen along a line D-D in  FIG. 16 .  
      The electric vacuum cleaner  101 B is characterized in that, when the dust collecting apparatus  107  is not accommodated in the dust collecting chamber  109  and the cardboard base  40 A of the disposable filter  40  is not fixed to the engagement member  41 , a stopper  80  provided on the dust cover  113  prevents the dust cover  113  from being closed and, when the dust collecting apparatus  107  is mounted in the dust collecting chamber  109  or the cardboard base  40 A of the disposable filter  40  is fixed to the engagement member  41 , the stopper  80  permits the dust cover  113  to be closed. Thus, the electric vacuum cleaner  101 B has substantially the same construction as the second embodiment except for an arrangement associated with the stopper  80 . Therefore, like components will be denoted by like reference characters, and no explanation will be given thereto.  
      Referring to  FIGS. 16 and 17 , the dust cover  113  has an attachment member  81  projecting from a laterally middle front portion of the interior surface thereof for attaching the stopper  80 . A laterally extending rotation shaft  82  is attached to a lower portion of the attachment member  81 . The stopper  80  has an anteroposteriorly elongated shape, and is rotatably retained by the rotation shaft  82  at a position slightly forward of a middle portion thereof. A tubular portion of a twist coil spring  83  is fitted around the rotation shaft  82 . The stopper  80  is biased clockwise as seen in  FIG. 16  by a biasing force of the twist coil spring  83  by fixing one end of the twist coil spring  83  to the attachment member  81  and fixing the other end of the twist coil spring  83  to the stopper  80 . Where no external force other than the biasing force from the twist coil spring  83  acts on the stopper  80 , an upper front surface portion of the stopper  80  abuts against a lower surface of a front wall  81 A of the attachment member  81  to prevent the stopper  80  from further rotating clockwise from a position shown in  FIG. 16 .  
      When the dust cover  113  is closed in this state, the operation portion  44  of the engagement portion  41  is located in the path of a front end of the stopper  80 . That is, if an attempt is made to close the dust cover  113  when the dust collecting apparatus  107  is not accommodated in the dust collecting chamber  109  and the cardboard base  40 A of the disposable filter  40  is not fixed to the engagement member  41 , the front end of the stopper  80  abuts against the upper edge of the operation portion  44  of the engagement member  41  to prevent the closing of the dust cover  113 . The stopper  80  has a projection  80 A projecting downward from a lower front end portion thereof. Thus, even if an external force is further applied to the dust cover  113  in a closing direction with the front end of the stopper  80  in abutment against the upper edge of the operation portion  44 , the projection  80 A prevents the operation portion  44  from forwardly riding over the stopper  80 .  
       FIG. 18  is a sectional view of the electric vacuum cleaner  101 B taken along the anteroposterior vertical plane and seen from the right side with the disposable filter  40  mounted therein.  
      When the disposable filter  40  is mounted, as shown in  FIG. 18 , the upper edge of the cardboard base  40 A of the disposable filter  40  is fixed by the pair of engagement projections  43 , so that the engagement member  41  is located in a position (fixing position) offset counterclockwise from the position shown in  FIG. 16 . If an attempt is made to close the dust cover  113  in this state, the dust cover  113  is permitted to be closed without the abutment of the front end of the stopper  80  against the engagement member  41  (operation portion  44 ).  
      The rear end of the stopper  80  is chamfered to be smoothly curved, so that breakage of the paper filter  40 B can be prevented which may otherwise occur when the paper filter  40 B of the disposable filter  40  accommodated in the dust collecting chamber  109  is brought into contact with the rear end of the stopper  80 .  
       FIG. 19  is a sectional view of the electric vacuum cleaner  101 B taken along the anteroposterior vertical plane and seen from the right side when the dust cover  113  is to be closed with the dust collecting apparatus  107  mounted in the cleaner.  FIG. 20  is a sectional view of the electric vacuum cleaner  101 B taken along the anteroposterior vertical plane and seen from the right side when the dust cover  113  is completely closed with the dust collecting apparatus  107  mounted in the cleaner.  
      As shown in  FIG. 19 , when the dust cover  113  is to be closed with the dust collecting apparatus  107  accommodated in the dust collecting chamber  109 , the casing  52  (an upper edge of the front member  52 A) of the dust collecting apparatus  107  is located in the path of the rear end of the stopper  80 . That is, when the dust cover  113  is closed with the dust collecting apparatus  107  accommodated in the dust collecting chamber  109 , the stopper  80  is rotated counterclockwise as seen in  FIG. 19  against the biasing force of the twist coil spring  83  by an action force from the casing  52  with the rear end of the stopper  80  in abutment against the casing  52 .  
      When the dust cover  113  is closed in the state shown in  FIG. 19 , the rear end of the stopper  80  is slid along the surface of the casing  52  to be lifted upward, whereby the stopper  80  is rotated counterclockwise as seen in  FIG. 19 . When the dust cover  113  is completely closed, the stopper  80  is in a state as shown in  FIG. 20 . If an attempt is thus made to close the dust cover  113  with the dust collecting apparatus  107  mounted, the stopper  80  is rotated by the action force from the dust collecting apparatus  107 , whereby the front end of the stopper  80  is displaced to be brought out of abutment with the engagement member  41  (operation portion  44 ). Thus, the dust cover  113  is permitted to be closed.  
      With this arrangement, the dust cover  113  can be closed when either the dust collecting apparatus  107  or the disposable filter  40  is mounted. However, when neither the dust collecting apparatus  107  nor the disposable filter  40  is mounted, the dust cover  113  cannot be closed. Therefore, the start of the operation of the electric vacuum cleaner  101 B is prevented with neither the dust collecting apparatus  107  nor the disposable filter  40  mounted. Thus, the electric vacuum cleaner  101 B is more convenient to use.  
      It is noted that the biasing means for applying the biasing force to the stopper  80  is not limited to the twist coil spring  83 , but any other resilient member may be used as the biasing means.  
       FIG. 21  is a sectional view of an electric vacuum cleaner  101 C according to a third variation of the second embodiment with neither the dust collecting apparatus  107  nor the disposable filter  40  mounted therein, the sectional view being taken along a horizontal plane and seen from an upper side.  FIG. 22  is a sectional view taken along a line E-E in  FIG. 21  with neither the dust collecting apparatus nor the disposable filter mounted in the electric vacuum cleaner  101 C.  
      The electric vacuum cleaner  101 C is characterized in that, when the dust collecting apparatus  107  is not accommodated in the dust collecting chamber  109  and the cardboard base  40 A of the disposable filter  40  is not fixed to the engagement member  41 , a stopper  90  provided in the dust collecting chamber  109  prevents the dust cover  113  from being closed and, when the dust collecting apparatus  107  is accommodated in the dust collecting chamber  109  or the cardboard base  40 A of the disposable filter  40  is fixed to the engagement member  41 , the stopper  90  permits the dust cover  113  to be closed. Hence, the electric vacuum cleaner  101 C has substantially the same construction as the second embodiment except for an arrangement associated with the stopper  90 . Therefore, like components will be denoted by like reference characters, and no explanation will be given thereto.  
      Referring to  FIGS. 21 and 22 , a stopper retainer  91  for retaining the stopper  90  is attached to a right side portion of the front wall  109 A of the dust collecting chamber  109  on the left side of the right guide member  46 R. The stopper  90  is retained pivotally about a laterally extending rotation shaft  92  attached to the stopper retainer  91 . An engagement projection  93  to be engaged with the stopper  90  projects from a front interior surface portion of the dust cover  113 . The stopper  90  has a vertically elongated shape, and its lower portion is retained pivotally about the rotation shaft  92 . The stopper  90  has a columnar projection  90 A provided on a front surface of the lower portion thereof. A compression coil spring  94  is provided between the stopper retainer  91  and the stopper  90  with its front end abutting against a rear surface of the stopper retainer  91  and with its rear end portion fitted around the columnar projection  90 A, whereby the stopper  90  is biased counterclockwise as seen in  FIG. 22  by a biasing force of the compression coil spring  94 . Where no external force other than the biasing force from the compression coil spring  94  acts on the stopper  90 , a distal edge of a rib  90 B projecting from a front upper surface portion of the stopper  90  abuts against the rear surface of the stopper retainer  91 . Thus, the stopper  90  is prevented from further pivoting counterclockwise from a position as shown in  FIG. 22 .  
      If an attempt is made to close the dust cover  113  in this state, an upper end of the stopper  90  is located in the path of the lower end of the engagement projection  93 . That is, if an attempt is made to close the dust cover  113  when the dust collecting apparatus  107  is not accommodated in the dust collecting chamber  109  and the cardboard base  40 A of the disposable filter  40  is not fixed to the engagement member  41 , the lower end of the engagement projection  93  abuts against an upper end face of the stopper  90  to prevent the closing of the dust cover  113 . The stopper  90  has projections  95  projecting upward from front and rear edges of the upper end face thereof. Thus, even if an external force is further applied to the dust cover  113  in a closing direction with the lower end of the engagement projection  93  in abutment against the upper end face of the stopper  90 , the projections  95  prevent the engagement projection  93  from forwardly or rearwardly riding over the stopper  90 .  
       FIG. 23  is a sectional view taken along the line E-E in  FIG. 21  with the disposable filter  40  mounted in the electric vacuum cleaner  11 C.  
      The stopper  90  is located in an insertion path along which the cardboard base  40 A of the disposable filter  40  is inserted. When the cardboard base  40 A is slid downward along the guide members  46  to mount the disposable filter  40 , the front face of the cardboard base  40 A is brought into sliding contact with a rear face of the stopper  90 . Thus, the stopper  90  is rotated clockwise from a position (initial position) shown in  FIG. 22  against the biasing force of the compression coil spring  94  by an action force from the disposable filter  40  (cardboard base  40 A) during the mounting of the disposable filter  40 . With the disposable filter  40  thus mounted, as shown in  FIG. 23 , the entire rear face of the stopper  90  abuts against the front face of the cardboard base  40 A of the disposable filter  40 . If an attempt is made to close the dust cover  113  in this state, the closing of the dust cover  113  is permitted without the abutment of the lower end face of the engagement projection  93  against the upper end face of the stopper  90 .  
       FIG. 24  is a sectional view of the electric vacuum cleaner  101 C taken along the horizontal plane and seen from the upper side with the dust collecting apparatus  107  mounted therein.  FIG. 25  is a sectional view taken along a line F-F in  FIG. 24  with the dust collecting apparatus  107  mounted in the electric vacuum cleaner  101 C.  
      As described with reference to FIGS.  8  to  10 , the rib  72  extending vertically (in the direction of the insertion of the dust collecting apparatus  107 ) projects forward from the front face of the dust collecting apparatus  107  (casing  52 ) on the lateral side (right side) of the inlet  50 . The stopper  90  is located in an insertion path along which the rib  72  of the dust collecting apparatus  107  is inserted. When the dust collecting apparatus  107  is slid downward to be mounted, the distal end face (front end face) of the rib  72  is brought into sliding contact with the rear face of the stopper  90 . Thus, the stopper  90  is rotated clockwise from the position (initial position) shown in  FIG. 22  against the biasing force of the compression coil spring  94  by the action force from the dust collecting apparatus  107  (rib  72 ) during the mounting of the dust collecting apparatus  107 . With the dust collecting apparatus  107  thus mounted, as shown in  FIG. 25 , the entire distal end face of the rib  72  of the dust collecting apparatus  107  abuts against the rear face of the stopper  90 . If an attempt is made to close the dust cover  113  in this state, the closing of the dust cover  113  is permitted without the abutment of the lower end face of the engagement projection  93  against the upper end face of the stopper  90 .  
      With this arrangement, the dust cover  113  can be closed when either the dust collecting apparatus  107  or the disposable filter  40  is mounted. However, the dust cover  113  cannot be closed when neither the dust collecting apparatus  107  nor the disposable filter  40  is mounted. Therefore, the start of the operation of the electric vacuum cleaner  101 C is prevented with neither the dust collecting apparatus  107  nor the disposable filter  40  mounted. Thus, the electric vacuum cleaner  101 C is more convenient to use.  
      The biasing means for applying the biasing force to the stopper  90  is not limited to the compression coil spring  94 , but any other resilient member may be used as the biasing means.  
      In the embodiments described above, the electric vacuum cleaners have been described, which include the connection hose attached to the main body and are operated by handling the connection hose while dragging the main body. However, the present invention is of course applicable to a so-called upright electric vacuum cleaner.  
       FIG. 26  is a vertical sectional view of an upright electric vacuum cleaner  300  to which the present invention is applied, the vertical sectional view being seen from a right side. The upright electric vacuum cleaner  300  includes a vertically elongated main body  301 , a handle  302  connected to an upper portion of the main body  301 , and a suction head  303  projecting from a lower front portion of the main body  301 . An electric fan  304  is incorporated in a lower portion of the main body  301 . A removable dust collecting apparatus  305  is attached to a back side of the main body  301 . The dust collecting apparatus  305  has a suction port  306 , a cyclonic flow path  307  for swirling air sucked from the suction port  306  to separate dust from the air by a centrifugal force, a dust collecting chamber  308  in which the separated dust is collected, an air outlet port  310  provided in a wall (front wall) of the dust collecting chamber  308  as having a great size, and a filter  311  attached to the air outlet port  310 .  
      The dust collecting apparatus  305  can be detached from the main body  301  by holding a handle  312  and pivoting an upper portion of the apparatus  305  rearward about a lower edge of the apparatus  305 .  
       FIG. 27  is a back view of the main body  301  with the dust collecting apparatus  305  detached.  
      Referring to  FIGS. 26 and 27 , the main body  301  has an inner wall  313  which is opposed to the air outlet port  310  and the filter  311  of the dust collecting apparatus  305  when the dust collecting apparatus  305  is attached. The inner wall  313  is positioned vertically, and includes an upper wall  314  and a lower wall  315 . As shown in  FIG. 26 , the upper wall  314  is located slightly forward of the lower wall  315  in the main body  301 , and the lower wall  315  is stepped slightly rearward with respect to the upper wall  314 . The upper wall  314  is opposed to upper portions of the air outlet port  310  and the filter  311  of the dust collecting apparatus  305 , and the lower wall  315  is opposed to lower portions of the air outlet port  310  and the filter  311  of the dust collecting apparatus  305 . The upper wall  314  has a multiplicity of openings  316 . That is, the upper wall  314  permits passage of air through the openings  316 , but the lower wall  315  does not permit air passage.  
      An air flow path  317  is defined in a front portion (on the left side in  FIG. 26 ) of the main body  301  partitioned by the inner wall  313 , and communicates with a lower flow path  318 . When the electric fan  304  performs a sucking operation, the air entering the dust collecting apparatus  305  flows through the air outlet port  310  and the filter  311  into the flow path  317  from the openings  316  of the upper wall  314 , and is discharged out of the main body  301  through the flow path  318 .  
      In this embodiment, with the dust collecting apparatus  305  attached to the main body  301 , a guide passage  319  is defined between the lower wall  315  of the inner wall  313  of the main body  301  and the portions of the air outlet port  310  and the filter  311  of the dust collecting apparatus  305  opposed to the lower wall  315 . The guide passage  319  which has a small width increases the flow rate of the air passing through the guide passage  319 . When the air flows forward (leftward in  FIG. 26 ) from the dust collecting chamber  308  through the lower portions of the air outlet port  310  and the filter  311 , the air swiftly flows upward through the guide passage  319  and smoothly flows into the flow paths  317 ,  318  through the multiplicity of openings  316  of the upper wall  314 . This is because the narrow guide passage  319  is provided in front of the filter  311 .  
      Although the air outlet port  310  and the filter  311  are not entirely opposed to the openings  316  of the inner wall  313 , the air flows from the dust collecting chamber  308  through the entire air outlet port  310  and the entire filter  311  toward the inner wall  313  of the main body  301 , and is properly discharged out of the electric vacuum cleaner through the flow paths  317 ,  318 .  
       FIG. 28  is a right side view of the dust collecting apparatus  305  detached from the main body  301 .  FIG. 29  is a front view of the dust collecting apparatus  305  with a filter cover  320  being opened. In  FIG. 29 , a reference numeral  308  denotes the dust collecting chamber. The air outlet port  310  which has a great size is provided in a front wall  309  of the dust collecting chamber  308 . The filter cover  320  is attached to a lower side of the air outlet port  310  to be opened pivotally about an axis  321 . The filter cover  320  has ribs  322 ,  323 , and the filter  311  (not shown in  FIG. 29 ) is held by the ribs  322 ,  323 .  
      Thus, the present invention is applicable to the upright electric vacuum cleaner.  
      It should be understood that the present invention be not limited to the embodiments described above, but various modifications may be made within the scope of the present invention defined by the appended claims.  
      This application corresponds to Japanese Patent Application No. 2004-217798 filed with the Japanese Patent Office on Jul. 26, 2004, the disclosure of which is incorporated herein by reference.