Abstract:
A suction cleaner ( 60 ) comprising a body ( 50 ); a compartment ( 42 ) for accommodating a dust collection bag ( 44 ); and a source of suction ( 32 ) for causing suction airflow into a bag in the compartment, wherein the source of suction is disposed at least partially beneath the compartment and communicates therewith by a passage ( 46 ) which extends from an upper region of the compartment.

Description:
BACKGROUND 
     The invention relates to a suction cleaner, more specifically to a suction cleaner which filters entrained dust out of the cleaner&#39;s suction airflow by using a dust collection bag in which the dust is retained for disposal. The cleaner described hereafter is of the so-called drum or canister type, but it will be appreciated that the principles of the invention will be applicable to cleaners whose shape differs from that described. 
     In suction cleaners with dust collection bags, there is a suction creating means, usually an electric motor connected to drive a fan, which transfers air from inside the suction cleaner, discharging through vents to the outside. The suction creating means is in fluid communication with the exterior of a dust collection bag, which has porous walls designed to trap dust but allow airflow therethrough. The interior of the bag is in fluid communication with an inlet which in the case of an “upright” type of cleaner is a cleaning head part of the cleaner&#39;s body, or possibly a hose, or in the case of a drum or canister type of cleaner is a suction hose, which the user directs to the area requiring cleaning. The flow created takes dust-filled air through the collection bag wherein the dust is retained, and the resultant clean air, filtered by the bag, flows to the suction creating means and thence to the outside of the cleaner. 
     It will be appreciated that the term “dust” is used herein as a general term to cover all of the matter that a suction cleaner would be used to collect, rather than as a literal term referring solely to household dust. For example, the term “dust” will cover hair fibres, loose carpet fibres, food particles, soil particles, wood dust, wood shavings, and any other debris, of a size which may range from microns to millimetres. 
     In a suction cleaner, it is desirable to have a large dust-carrying capacity, so that it requires emptying less frequently. To address this requirement, a large collection bag could be provided, but this would require a larger volume inside the cleaner and thus create a larger suction cleaner as a whole, requiring more material to manufacture and more storage space. 
     A favourable solution therefore is to ensure that the bag provided is filled as close as possible to its capacity, referred to herein as a high “fill ratio”, and this is dependent upon the path of the airflow which carries the dust through the bag. To this end, many drum-type suction cleaners have the motor disposed overhead of the bag, because this configuration allows some of the volume above the centreline of the inlet port to be filled. However, as the motor is relatively heavy, this results in the cleaner&#39;s having a high centre of gravity, making it less stable. This makes it more likely that the cleaner will fall over in use when being pulled along by the hose, especially when the castors commonly used on such suction cleaners have to climb small level differences, such as passing over a cable on the floor, or a door threshold. 
     The cable for the motor must be relatively thick, due to the power required by the electric motor, which is generally above 1 kW. In addition, it is desirable to provide a long cable so that the operating range of the cleaner from a power supply socket is increased. These factors result in a heavy cable. Many suction cleaners have the cable storage towards the top of the device for ease of access by the user, but this also results in a high centre of gravity, and instability. 
     SUMMARY 
     The present invention aims to address the above-described problems. 
     According to one aspect of the invention, we provide a suction cleaner comprising a body; a compartment for accommodating a dust collection bag; and a source of suction for causing suction airflow into a bag in the compartment, wherein the source of suction is disposed at least partially beneath the compartment and communicates therewith by a passage which extends from an upper region of the compartment. 
     The arrangement, in a suction cleaner in accordance with the invention, of the dust-bag receiving compartment, the source of suction, and the passage therebetween, enables a high degree of filling of the dust bag to achieved in use. In addition, the disposition of the source of suction generally beneath the compartment gives the cleaner a low centre of gravity. 
     The passage between the compartment and source of suction may be afforded by a duct extending upwardly from the latter, terminating in the vicinity of an upper surface of the compartment. Preferably the duct terminates at a position generally opposite a hose inlet to the compartment. 
     A suction cleaner in accordance with the invention may further comprise a storage device for electrical cable, preferably in a lower part of the body of the cleaner. Such disposition of a cable storage device, conveniently a cable reel, also assists in achieving a low centre of gravity for the cleaner as a whole. The cable reel may provide for winding of the cable onto the cable reel by rotation of the latter, which rotation may be effected by a manually operable rotary member such as a crank handle. 
     Such a manually operable rotary member may be disposed at a side part of the body of the cleaner, rotatable about an axis which extends generally transversely of the body and also generally transversely of the axis of rotation of the cable reel. 
     A one-way drive device may be operative between the rotary member and cable reel, so that when cable is drawn off the cable reel the cable reel may be rotated in one direction without causing rotation of the rotary member. When cable is to be wound onto the cable reel, the rotary member may drive the cable reel in the direction to cause such winding. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features of the invention will now be described, by way of example only, with the reference to the accompanying drawings, of which: 
         FIG. 1  is an exploded view of an embodiment of suction cleaner according to the invention, from the front; 
         FIG. 2  is an exploded view of the suction cleaner according to the invention from the rear; 
         FIG. 3  is a cutaway view of the suction cleaner according to the invention from the left, with a visual representation of paths of airflow therein; 
         FIG. 4  is a cutaway view of the suction cleaner according to the invention from above, with a visual representation of the paths of airflow therein; 
         FIG. 5  shows the suction cleaner according to the invention from the front; 
         FIG. 6  shows the suction cleaner according to the invention from the left; 
         FIG. 7  shows the suction cleaner according to the invention from the rear; 
         FIG. 8  shows the suction cleaner according to the invention from the right; 
         FIGS. 9 and 10  show, diagrammatically, from different viewpoints the relationship between operative components of a cable winding assembly of the suction cleaner according to the invention; and 
         FIG. 11  illustrates a one way drive mechanism which may be incorporated in the cable winding assembly of the cleaner according to the invention. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to the drawings, these show the main components of a suction cleaner  60  according to the invention. It comprises an outer body  50 , which conveniently is a plastics moulding of hollow and generally cylindrical configuration, and which defines an internal volume when fitted with a lid  54 . The lid  54  is releasably connected to the main body  50  by means of clips  56  and is provided with a carrying handle  58 . 
     At the lower end of the body, there is a base  29  which is provided with wheels  62  and castors  64 , the base  29  having a portion  31  which fits within the lower edge of the body  50 , and a central recess  33 . A bottom cover  28  beneath the base  29  supports an annular cable reel  24  for rotation about an upright axis, the cable reel having supporting rollers  26  ( FIG. 9 ) which engage the bottom cover  28 , so that the cable reel is mounted inside a compartment defined between base  29  and cover  28 . 
     A suction creating device in the form of an electric motor  32 , drivingly connected to a fan or impeller, is disposed in a lower portion of the cleaner  60 , mounted concentrically within the cable reel  24  and supported in the recess  33  of the base  29 . The cable reel  24 , rotatably supported by its rollers  26  surrounds the motor  32  and is rotatable by a user operating a winding mechanism  10 , described hereafter. 
     Referring now to  FIG. 3 , the operative internal components of the invention can be seen. A hose inlet  52  near the uppermost edge of the body  50  provides fluid communication from an external suction hose to a bag-receiving compartment  42 , inside which a dust collection bag  44  is disposed. The motor  32  is housed in a compartment partially below the bag-receiving compartment  42 , separated therefrom by wall  34 , and is in fluid communication with the bag-receiving compartment  42  by way of a duct  46  and motor compartment air inlet aperture  40 , the duct inlet  48  being disposed adjacent the top of bag-receiving compartment  42  facing the lid  54 . The path of suction airflow in the cleaner is shown at A in the drawings, entering the suction cleaner  60  through the hose inlet  52 , passing through the upper corner of bag  44  and into duct inlet  48 . The air passes downwardly through duct  46 , which is shaped to direct the air radially inwards and into the motor  32  through motor compartment air inlet  40 . 
       FIG. 4  shows the path of exhaust airflow from the motor/fan assembly  32 . The inlet air path A is shown, and the exhaust airflow B is through an exhaust duct  38  leading to exhaust outlet vents  36 A and  36 B. 
       FIGS. 7, 8, 9 and 10  show the operative components of the cable reel  24  and its winding mechanism  10  according to the invention. The winding mechanism  10  comprises a gear wheel  14  having a handle  12  and peripheral teeth  16 , the gear wheel  14  being rotatably supported on the body  50  by a bearing assembly  17 , behind an access panel  15 . The gear wheel&#39;s teeth  16  engage with the teeth of a smaller-diameter portion  18  of a secondary gear wheel also having a larger-diameter portion  20 , whose teeth engage with teeth  22  on the cable reel  24 . These gears allow the rotational movement provided by the user to be translated into rotation of the cable reel  24  at a convenient gear ratio. 
     The cable reel as above-described provides for storage of a sufficient length of flexible electrical power supply cable or cord to enable the cleaner to be moved around and used within a reasonable distance, e.g. a few metres, of a mains electrical power supply socket outlet. When substantially all the length of such a cable is stored on the reel within the body of the cleaner, the plug connector at the end thereof may fit in a receiving formation provided at an externally-accessible part of the body  50  or base  29 , accessible so that by pulling the plug and cable sufficient of the cable for use of the cleaner in the required position can be drawn from the cable reel. After use of the cleaner, the user may turn the handle  12  of gear wheel  14  to rotate the cable reel  24  and thereby wind the cable back onto the reel. 
     To avoid rotation of the gear wheel  14  with its handle  12  when the cable is being drawn off the cable reel, a one-way operable driving mechanism may be incorporated in the drive train between the handle  12  and the cable reel.  FIG. 11  illustrates one arrangement by which such one-way drive mechanism may be provided in association with the gear wheel  14 . 
       FIG. 11  shows, diagrammatically, the gear wheel  14  with its gear teeth  16  on its external periphery. In its interior, it has a number of circumferentially spaced engagement formations  70  each with a circumferentially extending wall portion  72 , a drive wall  74  inclined so as to define slightly less than a right angle between it and the circumferential wall  72 , and a lead-in wall  76  defining an obtuse angle between it and the circumferential wall  72 , facing the interior of the gear wheel  14 . 
     The handle  12  is connected to a hub part  78  in a central region of the gear wheel  14 , and operatively interposed between the hub part  78  and gear wheel  14  there is a drive member  80  which carries three circumferentially spaced drive elements indicated generally at  82 . The drive elements  82  are supported in recesses in the drive member  80  and each has a nose portion  84  shaped to engage the acute angle between the circumferential wall  72  and drive wall  74  of each of the recesses  70  in the gear wheel  14 . The drive elements are moveable in their respective recesses and are lightly spring biased inwardly of their respective recesses by springs  86 , so that their nose portions  84  are clear of the engagement formations  70  in the gear wheel. The hub member  78  has engagement faces  88  which are engageable with rear portions of the drive elements  82 , so that when the hub portion  78  is turned in the anti-clockwise direction (with reference to  FIG. 11 ) by the handle  12  it moves angularly relative to the drive member  80  so that the drive elements are urged outwardly of their recesses in the member  78  into engagement with the drive walls and circumferential walls of the most closely-adjacent ones of the formations  70  in the gear wheel  14 , so that continuing rotation of the handle  12  in the anti-clockwise direction will turn the gear wheel  16  thereby causing the cable reel to be rotated in the direction to cause the cable to be wound onto the reel. When such rotation of the cable has ceased, e.g. when the cable has been completely wound onto the reel, cessation of turning of the handle  12  will enable drive elements  82  to retract back into their recesses in the member  78 , so that there is no driving connection between the handle and the gear wheel  14 . The cable may be drawn off the reel without causing rotation of the handle  12 . 
     In use of the cleaner described above, the disposition of the inlet  48  leading to the suction-creating means at the upper end of the bag-receiving compartment at  42  has the effect that a high fill ratio of the bag can be attained. In addition, the disposition of electric motor and fan assembly  32  at the base of the cleaner gives the cleaner a low centre of gravity, assisted by the disposition of the cable reel around the motor. 
     When used in this specification and claims, the terms “comprises” and “comprising” and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components. 
     The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.