Abstract:
Floor cleaning apparatus ( 10 ) comprises a dispenser ( 50 ) for dispensing particulate cleaning material onto a floor surface. Particulate material is held in a hopper ( 52 ). Movable part ( 70, 71 ) is movable with respect to the hopper ( 52 ) to define a dispensing aperture ( 75 ) and for imparting movement to particulate material in the hopper towards the dispensing aperture ( 75 ). Adjustment means ( 80 ) are provided for adjusting the operational width of the dispensing aperture ( 75 ) so as to provide a range of dispensing settings. Adjustment means ( 80 ) is pivotally mounted to the movable part ( 70, 71 ) about a rotational axis ( 82 ) and has an outer surface which acts as a camming surface. The radius of the outer surface varies in value in different angular directions about the rotational axis ( 82 ). Adjustment means ( 82 ) provides a discrete set of different spacings between the cam ( 40 ) and movable part ( 71 ).

Description:
FIELD OF THE INVENTION 
   This invention relates to floor cleaning apparatus for dispensing particulate cleaning material onto a floor surface. 
   BACKGROUND OF THE INVENTION 
   Floor coverings such as carpets and rugs are prone to marks and stains. Floor coverings can be cleaned in a number of ways, which can be classified as ‘wet’ or ‘dry’ cleaning methods. Wet cleaning methods such as washing or shampooing the floor covering have the disadvantage that they can cause shrinkage of the floor covering. Dry cleaning generally involves depositing a powdered composition onto the floor covering which can readily absorb soil and contaminants from the floor covering. The powder is worked into the floor covering with the aid of a brush. Finally the dirty powder can then be removed from the floor covering by a vacuum cleaner. While such compositions are called ‘dry’, in that they flow as a powder at room temperature, they usually contain a quantity of liquid such as water or organic solvents. 
   The cleaning powder needs to be dispensed on to the floor covering. U.S. Pat. No. 4,268,935 and U.S. Pat. No. 5,101,532 describe powder-dispensing machines for use in cleaning carpets. In U.S. Pat. No. 5,101,532, the machine has a hopper on the front of the machine for storing dry-cleaning powder. At the front, lower part of the hopper there is a jaw which is formed by a lower flap which is hingedly fixed to the hopper. In use, the flap is oscillated about a mean gap width of around 4 mm so as to dispense powder onto the floor surface. The position of the lower flap is controlled by a user-operated control which moves the flap between one of two fixed positions: a dispense position, in which the flap is set to the 4 mm gap, and a grooming and vacuuming position in which the flap seals the hopper to prevent any powder escaping from the hopper. In use, the machine dispenses powder onto the floor surface at a controlled rate. The dispenser is designed to work well with a particular composition of dry cleaning powder, which has particular properties, such as the size of the particles. However, changes which are made to the composition of the powder, such as to improve cleaning performance of the powder, may change the physical properties of the powder which may in turn require changes to the design of the dispenser. This is undesirable for the manufacturer and for the user, who will be unable to take advantage of the improved cleaning powder without replacing their dispensing machine with a model which is more suited to the new powder. Also, while the controlled rate of dispensing powder may be generally suitable for normal use, there are occasions when a user would want to dispense a different amount of powder. 
   SUMMARY OF THE INVENTION 
   The present invention seeks to provide a floor cleaning apparatus in which a user has more control over the dispensing operation. 
   Accordingly, the present invention provides a floor cleaning apparatus comprising a dispenser for dispensing particulate cleaning material onto a floor surface, the dispenser comprising a hopper for holding the particulate material, a part which is movable with respect to the hopper to define a dispensing aperture and for imparting movement to particulate material in the hopper towards the dispensing aperture and wherein adjustment means are provided for adjusting the operational width of the dispensing aperture so as to provide a range of dispensing settings. 
   The adjustment means allows a user to vary the amount of particulate material that is dispensed from the hopper. For example, when treating heavily stained surfaces, the user can adjust the apparatus to dispense more material. Also, the adjustment means allows the apparatus to cope with different compositions of particulate material. A narrow gap can be used with fine particulate material and a wider gap can be used with coarser particulate material. 
   The term ‘floor surface’ is intended to cover any type of floor covering such as carpet or a rug which may be present on the actual surface of the floor. 
   Preferably the movable part comprises a cam follower which cooperates with a cam to move the movable part and the adjustment means is operable to vary the spacing between the cam and the movable part. 
   Preferably the adjustment means comprises a member which is pivotally mounted to the movable part about a rotational axis, the member having an outer surface which acts as a camming surface, the radius of the outer surface varying in value in different angular directions about the rotational axis. 
   Preferably the adjustment means provides a discrete set of different spacings between the cam and the movable part. More preferably, the adjustment means is resiliently held in each of a plurality of positions corresponding to the positions where the adjustment means provides a different spacing and the positions are labelled, such as by letters or numbers. This allows a user to quickly and reliably adjust the operating width of the aperture. A user can simply refer to an operating manual which states the recommended setting label for the particular type of cleaning material that they are using or the degree of cleaning they require, and set the adjustment means to that setting. Alternatively, with an adjustment means in the form of an adjuster screw, the adjustment means can provide a continuous range of settings for the operating width of the aperture. 
   Preferably the dispenser is pivotably mounted to a main body of the apparatus to expose the adjustment means. 
   The dispenser can be an integral part of the floor cleaning apparatus or it can be a removable attachment to the apparatus. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: 
       FIG. 1  shows a vacuum cleaner incorporating dispensing apparatus according to an embodiment of the invention; 
       FIG. 2  shows the dispensing apparatus with the dispensing aperture open; 
       FIG. 3  is a cross-section through the dispensing apparatus of  FIG. 2 ; 
       FIG. 4  shows the adjustable part of the dispensing apparatus of  FIGS. 2 and 3 ; 
       FIGS. 5 and 6  show alternative forms of the adjustable part of the dispensing apparatus of  FIGS. 2 and 3 ; 
       FIG. 7  shows just the dispensing plate of the dispensing apparatus of  FIGS. 2 and 3 ; 
       FIG. 8  shows an alternative position for the separating means; 
       FIG. 9  is a cross-section through an alternative embodiment of the dispensing apparatus of the invention; and 
       FIG. 10  shows an alternative arrangement to the fixed wire. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  shows a vacuum cleaner  10  which includes a dispenser  50  for dispensing particulate dry cleaning material onto a floor surface. The vacuum cleaner  10  is largely of a conventional design. The main body  11  has a motor housing  12  at its lower end. A cleaner head  15  is rotatably mounted to the motor housing to allow the cleaner head to remain in contact with the floor surface as the main body  11  is moved rearwardly into a normal operating position for upright cleaning. The cleaning head  15  includes an inlet  18  through which dirty air can be drawn into the cleaner and a brush bar for beating the floor surface. The main body  11  supports separating apparatus  20  which separates dirt and dust from the dirty air. The separating apparatus is preferably cyclonic separation apparatus using two cyclonic separation stages although it can take the form of a bag or other form of separator. Cyclonic separators have been found to be particularly effective at separating the dirty dry cleaning powder from the air drawn in to the cleaner  10 . The separating apparatus  20  is removable from the main body  11  to allow the separating apparatus to be emptied. 
   The vacuum cleaner  10  is modified with respect to a normal cleaner to support dispenser  50 . The dispenser  50  is more clearly shown in  FIGS. 2–10 . The dispenser  50  fits onto the upper face of the cleaner head  15  and extends transversely across the cleaner head  15 , parallel to the floor surface. A lug on each side of the dispenser  50  fits in a slot on each forward corner of the upper face of the cleaner head  15 . These slots are shaped to allow the dispenser  50  to pivot from a generally upright position in which the dispenser  50  is inoperable to an operable position in which the dispenser  50  lies flush with the cleaner head  15 . The dispenser  50  is shown in the operable position in  FIG. 1 . In the operable position an arm  53  on each side of the dispenser  50  fits in a recess on the side of the cleaner head  15  and a flange on the rear face of the dispenser  50  is received by a clamp on the cleaner head  15 . The clamp is linked to a foot pedal  40  so that when a user presses on the foot pedal  40  the clamp is opened to release the dispenser  50 . As shown in  FIG. 3 , the dispenser  50  comprises a hopper housing  52  whose rear face is defined by a plate  70  which is pivotally mounted to the housing  52  about an axle  73 . The forward, upper face of the hopper is defined by a lid  55  which is pivotally mounted to the housing  52 , the lid  55  opening from the uppermost end. The chamber  60  defined by the housing  52 , plate  70  and lid  55  has a volume which is sufficient to receive a useful quantity of dry-cleaning powder. An arm  71  (best seen in  FIG. 7 ) extends from the plate  70 . 
   The cleaner head  15  includes a cam  40  for moving the arm  71  of the hopper plate  70  of the dispenser  50 . The cam  40  is driven by way of the main motor (not shown) of the cleaner  10  and a drive shaft  45 . The cam  40  is mounted inside the cleaner head  15 , and a slot extends inwardly from the outer casing of the cleaner head towards the cam  40 . A cam guard  30  is mounted within the slot and serves as both a cam follower and a guard. Cam guard  30  is pivotable about axle  32  and is normally biased, by spring  34 , into a position in which it lies flush with the outer surface of the cleaner head  15 . When the dispenser is mounted on the cleaner head  15 , the cam guard  30  is pressed inwardly against the spring  34 , to lie against the cam  40  and can then follow the shape of the cam  40 . The guard makes it impossible for a user or a child to trap a finger or an object between the cam and the casing, thus preventing injury to a user and damage to the cleaner. 
   The lower parts of the hopper plate  70  and housing  52  form a jaw which defines a dispensing aperture  75 . The aperture is defined by a flange  72 , which extends outwardly from the lower, forward part of housing  52 , and end  74  of hopper plate  70 . 
   Plate  70  is driven by the cam  40  in the cleaner head  15 , motion of the cam being transmitted to the plate  70  via the cam guard  30  and adjustment wheel  80 . Motion of the plate  70  is constrained by spring  56  which fits between the plate  70  and housing  52 . Plate  70  also carries a wire  90 . The wire extends across the full width of the plate, parallel with the plate and the floor surface. The purpose of the wire  90  is to separate clumps of powder prior to the powder being dispensed onto the floor surface. Rapid movement of the plate  70 , and therefore the wire  90 , serves to cut through the powder. 
   In use, the width of aperture  75  will vary as the plate  70  is driven by the cam  40  in the cleaner head  15 . Aperture  75  has a mean width, the width increasing or decreasing a small amount from this mean width as the plate  70  is driven. The mean width of the aperture has an effect on the rate at which powder is dispensed. The mean width of aperture  75  is controlled via adjustment wheel  80 . Adjustment wheel  80  fits between the arm  71  and the cam guard  30  and, in addition to performing a cam following function, it controls the distance between these parts, which in turn controls the spacing between part  74  of plate  70  and flange  72 , i.e. the width of the aperture  75 . The adjustment wheel can be set in one of a number of different positions, each position providing a different distance between the cam guard  30  and plate  70 . The adjustment wheel  80  is pivotably mounted about an axle  82  which is supported on arm  71 . The wheel  80  has a different radius in different angular directions about the axle and is resiliently held in each of the differently dimensioned positions.  FIG. 4  shows the wheel in more detail. The wheel is generally rectangular in shape and comprises two spaced apart members  83 ,  84  which are separated by a gap  85 . The outer surface of the members  83 ,  84  is used to press against the cam follower of the cleaner head. The wheel  80  is mounted eccentrically about axle  82  to provide four differently dimensioned positions which are labelled in  FIG. 4  as d 1 , d 2 , d 3 , d 4 . Within the gap  85  there is a spider-like part  86  which has the function of retaining the wheel  80  in the differently dimensioned positions. The spider  86  has four grooves around its outer surface which cooperate with a projection  87  carried by arm  71 . The wheel can be snapped in to each of the positions by rotating wheel  80  against the resilience of projection  87 . Each of the positions of the wheel are labelled, such as by numbering, to aid a user in selecting an appropriate setting for the dispenser. Typically, each setting of the adjustment wheel changes the mean width of aperture  75  by 1 mm. 
     FIGS. 5 &amp; 6  show alternatives to the adjustment wheel  80  which also achieve the same effect of varying the distance between the arm  71  and cam guard  30 . In  FIG. 5 , an adjustment screw  180  is received in a threaded bore through the arm  71  of the hopper plate  70 . By turning the screw, the distance d can be varied. In use, the rapid vibration of the arm  71  may cause the screw to rotate, thereby altering the distance d and the width of aperture  75 . To prevent this rotation, the screw  180  has a tab  185  which engages with ribs on the upper surface of arm  71 . Tab  185  can project radially outwardly from the head of the screw  180 , axially between the screw head and the upper surface of the arm  71  or a combination of these, as shown in  FIG. 5 . In  FIG. 6  part  280  of arm  71  represents the end of arm  71  which lies alongside the cam guard  30  of the cleaner head. Part  280  is rotatable with respect to the remainder of the arm  71  about axis  282 . As with the adjustment wheel  80 , part  280  is mounted eccentrically with respect to axis  282  so that each position of part  280  provides a different distance d 1 , d 2 , d 3 , d 4  between the arm and the cam follower  30 . In each of these embodiments it will be appreciated that the cam guard  30  could be omitted and the adjustment means itself, whether it is the adjustment wheel  80 , adjustment screw  180  or rotatable part  280  directly follows the cam  40 . 
   The dispenser  50  has a self-closing action. Spring  56  acts on arm  71  of the hopper plate  70  at all times. When the dispenser  50  is removed from the cleaner head, spring  56  acts on arm  71  so as to maintain plate  70  in a closed position where edge  74  of the plate  70  is sealed against, or rests closely to, the edge of flange  72 . This prevents cleaning powder from escaping from the dispenser  50 . This closed position is shown in  FIG. 9 . When the dispenser  50  is fitted to the cleaner head in preparation for use, arm  71  is urged upwards (as viewed in  FIG. 3 ) against the bias of spring  56  which moves edge  74  of plate  70  away from flange  72  of the housing  52 , thereby opening the dispensing aperture  75 . The position of the wire  90  upstream of the flange  72  allows the plate  70  to properly close, while the wire still provides an effective separating action on powder at the aperture  75 . The biasing action of spring  56  could be achieved with an alternative form of resilient device. The biasing action could also be achieved by positioning the spring in a different position to the one shown in  FIG. 3 . For example, a spring could be coiled around axle  73 , the ends of the spring acting on the plate  70  and housing  52 , although this alternative position loses the mechanical levering advantage that is gained from the position shown in  FIG. 3 . 
   As described above, a wire  90  extends across the dispenser  50  in the region of the dispensing aperture  75 . A particularly effective separating action on the cleaning powder has been experienced using a wire having a diameter of 0.6 mm which is spaced from the plate  70  by a distance of 7 mm. However, it will be appreciated that a wire having a different diameter and separated from the plate by a different distance would also provide similar advantages. A braided wire has been found to offer the required durability although it is possible to use single strand wire. A synthetic cord such as Nylon would also be suitable. 
     FIG. 7  shows just the hopper plate  70  and the parts which fit to the plate. A ferrule  92  is crimped to each end of a length of wire  90 . The ferrule  92  is retained in a recess  76  on each side of the hopper plate  70 . The wire  90 , is spaced from the surface of the plate  70  by supports  77  which extend outwardly from the plate  70  into the chamber  60 . The outer surface of each support is grooved so as to retain the wire  90  in position. The wire  90  is of such a length that it is retained under tension between the supports  77 . This ensures that the wire is taut at all times, which improves the cutting action of the wire  90  on the cleaning powder. 
   While the wire has been found to be particularly effective when it is carried by the plate  70 , it could alternatively be attached to each side of the housing  52  near to the flange  72 , as shown in  FIG. 8 . In this alternative embodiment, any clumps of powder on the plate  70  are moved upwardly towards the wire where they are separated by the fixed wire. While a single wire  80  is shown in the FIGS., it is possible to use two or more wires which are spaced apart perpendicularly from the surface of plate  70  or laterally along the plate  70 . 
   A further alternative to the fixed wire is shown in  FIG. 10 . An L-shaped part  192  is pivotably mounted to each side of the hopper housing  52 . A wire  190  is secured to each of the parts  192 . One of the arms of parts  192  is biased by spring  196  so that it rests against the surface of hopper plate  70 . Movement of the hopper plate  70 , shown as  197 , causes the parts  192  to move in the manner shown by arrow  198 , which in turn causes the wire  190  to move in the manner shown by arrow  199 . Thus, movement of the hopper plate  70  causes wire  190  to perform a cutting action. By appropriate selection of the lengths of the two L-shaped arms of part  192 , a levering advantage is gained, such that a small movement of the hopper plate  70  is converted into a larger movement of wire  190 . The arm which contacts the plate  70  is shorter than the arm which carries the wire  190 . As an alternative to using a wire, a cord, blade or some other material which provides a cutting action could be used. 
   The operation of the cleaner will now be described. To fill the dispenser  50 , a user opens the lid  55  and pours cleaning powder into the hopper, filling chamber  60  of the hopper. The cleaner is operable in the following modes: dispense, groom and vacuum. 
   In dispense mode, the cleaner operates to dispense cleaning powder from the dispensing hopper  50 . Dispenser  50  is fitted to the cleaner head  15 . The separating apparatus  12  is removed from the main body  11  of the cleaner  10 . The cleaner detects the removal of the separating apparatus  12  and turns off the suction fan (not shown). Alternative means can be used to control the cleaner to turn off the suction fan, such as by a manually operated control switch or a switch which is responsive to the position of the dispensing apparatus on the cleaner head. A user pushes the hopper  50  so that it is grasped by the clamp on the cleaner head  15 . In this position, plate  70  and adjustment wheel  80  press against cam guard  30  and the cam guard  30  is pressed into an operational position against the cam  40  in the cleaning head  15 . Plate  70  is moved, against the action of the spring  56 , into a dispensing position in which dispensing aperture  75  is open. When operated, the cleaner head cam  40  rotates, causing plate  70  to vibrate at high speed. Typically, the plate vibrates at a rate of around 3000 rpm. Vibration of the plate  70  agitates powder in the cleaning dispenser and causes the powder to move downwardly towards dispensing aperture  75 . Flange  72  at the dispensing jaw regulates the flow of powder from the dispenser. Wire  90 , carried by plate  70 , serves to separate the powder before it is dispensed, thus preventing clumps from being dispensed or from forming in the dispensing aperture  75 . A user pushes the cleaner across the floor surface where they require cleaning and powder is dispensed from hopper  50  through aperture  75  on to the floor surface in an even and controlled manner. 
   In groom mode, the cleaner operates to brush the dispensed powder into the floor covering, with the brush bar in the cleaner head  15  operating at a reduced speed to achieve this grooming action. The user operates foot pedal  40  and lifts the dispenser  50  forwardly from the clamp. As soon as the dispenser is lifted, plate  70  moves under the bias of spring  56  into a position in which it closes the dispensing aperture  75 . The dispenser can sit on the cleaner head  15  in this inoperable position or it can be removed. In either case, the dispensing aperture  75  remains closed. The user moves the cleaner across the region of the floor surface where powder was dispensed so as to groom the powder into the carpet. If a user finds that they have not properly covered the floor surface with cleaning powder and would like to dispense more cleaning powder, they can push the dispenser  50  into the engaged position on the cleaner head, whereby plate  70  moves to open dispensing aperture  75  and the dispenser will function. 
   In vacuum mode the cleaner operates in a conventional manner to draw dirty air into the cleaner via the cleaner head  15 . The dispenser  50  can be used in its inoperable position or it can be removed from the cleaner, as described above for groom mode. The separation apparatus  12  is returned to an operational position on the main body  12  of the cleaner. The user moves the cleaner across the region of the floor surface where powder has been dispensed and groomed. The brush bar operates at normal speed and serves to agitate the floor covering. A combination of the agitation and the vacuum serve to draw dirty cleaning powder from the floor covering and into the cleaner  10  via the cleaning head  15 . The separating apparatus  12  separates the dirty powder from the air and exhausts cleaned air to the atmosphere. 
   Variations will be apparent to a person skilled in the art and are intended to fall within the scope of the present invention.