Abstract:
The specification discloses an impeller for cleaning devices. A plurality of impeller segments are slipped over a twisted flat wire to provide the impeller. Each of the impeller segments preferably includes a plurality of paddles, and a central section with a non-cylindrical opening for receiving said twisted flat wire.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to debris impellers for vacuum cleaners, floor sweepers, surface cleaning extractors, or the like. 
     Floor cleaners are known which use a rotating brush with bristles thereon for lifting debris off a floor, or out of a carpet or rug. These rotating brushes also throw the debris into a dirt pan or bag. A problem with such brushes is hair, fur, lint and other debris tends to get caught in the bristles which prevents effective lifting and throwing of debris into the debris receptacle used therewith Combs have been used to remove debris caught in the bristles of such brushes. Although such combs remove the debris stuck in the bristles as the brush is rotated, these combs increase the amount of force required to turn the brushes, and thus increase the force required to move the cleaning device Use of a comb and brush is particularly a problem on slippery floors where the wheels which drive the brush will slide on the floor as the force required to turn the brushes through the comb is greater than the friction between the drive wheels and the floor. 
     An alternative to the bristle brush is an impeller constructed from elongated blades which are received in slots within a metal core. One such impeller is shown in U.S. Pat. No. 4,845,797 issued to Kobayashi which includes an extruded metal core having slots formed therein to receive blades. Another is shown in U.S. Pat. No. 1,267,304 issued to Adams which includes a core having slots for receiving blades having holes therein. United Kingdom Patent 642,819 shows another impeller which is an assembly of metal brackets which form channels for receiving blades therebetween. The elongated blades of these impellers may include dimples, lateral ribs, or holes for lifting debris. These blades, like the brushes described above, collect debris which must be removed in order for the blade to continue to effectively pick up debris. In order to remove such debris, a surface must be positioned to contact the blades as they rotate, which increases the force required to rotate the impeller, and thus has the disadvantage of increasing the force required to push the machine and turn the impeller drive wheels. Additionally, these impellers are relatively difficult to manufacture and consequently are relatively costly. Another disadvantage of some of these impellers is the blades are made from a material which mars the floor as the impeller rotates, or interact with the plasticizer in some floors, such as vinyl flooring when the impeller is at rest, which causes the blade material or coloring to transfer to the floor, or react with chemicals used to clean floors in residential or commercial settings. 
     SUMMARY OF THE INVENTION 
     The present invention comprises an impeller formed by a plurality of individual integrally molded impeller segments, each of which includes a central body and a plurality of paddles. Significant manufacturing advantages are realized by having a plurality of substantially identical molded impeller segments each of which has a non-cylindrical opening adapted to receive a twisted flat wire axle whereby said impeller may be assembled by slipping said segments over the axle. These and other objects, advantages and features will become apparent upon review of the following specification in conjunction with the drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a bottom perspective of a mechanical sweeper including impellers according to the invention; 
     FIG. 2 is a perspective view of an impeller assembly; 
     FIG. 3 is a side elevation of an impeller segment of the invention; 
     FIG. 4 is a plan view of a twisted axle of the invention; 
     FIG. 5 is an end view of an axle of the invention: and 
     FIG. 6 is a fragmentary side view of the remote end of a paddle designated by VI in FIG. 3. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring initially to FIG. 1, impellers 24 and 25, according to the invention, are illustrated in a mechanical sweeper 9. Mechanical sweeper 9 includes six wheels A front wheel 10, a middle wheel 11, and a back wheel 12 are provided on one side, and a front wheel 13, a middle Wheel 14 and a back wheel 15 are provided on the other side. Additionally, brushes 18, 19, 20 and 21 are provided to move debris which is located in the path of the wheels and outside the cleaning area of the impellers. Front impeller 24 and back impeller 25 are provided to pick up debris and throw it into a front dirt bin 27 and a back dirt bin 28, respectively. Impeller 24 is driven by a drive wheels 30 and 31, which in turn are driven by a middle wheels 11 and 14 when the sweeper is moving backward. Impeller 24 is illustrated with eleven impeller segments 34-44, although more or less than eleven segments may be provided. Impeller 25 includes eleven impeller segments 46-56. Impeller 25 is driven by drive wheels 57 and 58 which, in turn, are driven by middle wheels 11 and 14 when the mechanical sweeper is moving forward 
     A perspective of impeller 24 is illustrated in FIG. 2. Impellers 24 and 25 are substantially identical and thus only impeller 24 will be described in detail below. Impeller 24 includes eleven identical impeller segments 34-44 which are slipped over a twisted flat wire 45. Each segment includes a central hub 60 (FIG. 3), as well as six identical elastic paddles 61-66. The paddles have respective ends 69-74 which are thicker than respective mid-sections 77-82. The thicker ends have sufficient mass to provide momentum for throwing debris into debris bin 27 or for pushing liquids. Thin mid-sections 77-82 provide substantial flexibility and spring which allows ends 69-74 to throw debris deep into debris bin 27. Additionally, impeller segments 34-44 include a central opening 85 in central body 60 for receiving the twisted flat wire 45 and keyed to insure rotation of the segments with rotation of the flat wire. The front and back surfaces of each of the paddles, such as 69 and 76 of paddle 70 (FIG. 2), are substantially rectangular and arced inwardly, and thus as seen from the side of the paddles (FIG. 3), have a generally elliptical curve. As shown in FIG. 6, a tip 74a is flat and rectangularly shaped as seen from a direction orthogonal thereto. Tip 74a thus forms a first linear projecting, edge 74b where curved surface 74d meets flat tip 74a and a second linear projecting edge 74c where curved surface 74d meets the flat tip 74a. The paddles thus form a generally pointed end joined with a curved surface which digs into carpets and rugs, and scoop debris and liquids off of a hard floor. 
     As illustrated in FIGS. 4 and 5, twisted flat wire 45 includes ends 90 and 91 which are oriented at an angle of approximately 90° with respect to each other. Ends 90 and 91 are connected by a substantially continuous helical curve therebetween. However, end portions 92 and 93 of twisted wire 45 near ends 90 and 91 may be substantially straight for receiving drive wheels 30 and 31 (FIG. 1) of impeller 24. The flat wire is twisted such that the paddles of the impeller segments will not be oriented linearly with respect to each other. The twist is such that when mounted on axle 45, impeller 34 and impeller 44 are rotationally positioned with respect to each other by greater than, or equal to, 360° divided by the number of paddles on each impeller segment and less than two times 360 divided by the number of paddles on each impeller segment. Thus, where six paddles are provided on each segment, the twist in wire 45 will position paddles 70 (FIG. 2) and 75 with an angle which is greater than 59° and less than 120°  therebetween 
     In operation, as mechanical sweeper 9 (FIG. 1) is moved over a surface in a forward direction, middle wheels 14 and 11 will be pressed against drive wheels 57 and 58 of rear impeller 25 which will drive impeller 25 to throw debris into bin 28. When the sweeper is moved in the opposite direction, drive wheels 11 and 14 will swing into contact with wheels 30 and 31 of impeller 24, causing impeller 24 to rotate and throw debris into bin 27. When impeller 25 is being driven by wheels 11 and 14, the floor will cause impeller 24 to rotate upon motion of the sweeper, whereas impeller 25 will be driven by the motion of the middle wheels. Similarly, when impeller 24 is driven by middle wheels 11 and 14, the floor causes impeller 25 to roll with the motion of the sweeper, whereas impeller 24 is driven by middle wheels 11 and 14. The paddles of segments 34-44 of impeller 24, and segments 46-56 of impeller 25, will sequentially come into contact with the floor as the respective impellers are rotated. The narrow portion 77-82 (FIG. 3) of the impeller paddles will be the point of flex and as the impeller paddles come off the floor ends 69-74 will spring back to the at rest position and thus throw the dirt into the dirt bins. 
     Impeller 24 is assembled in a relatively simple manner. A flat wire 45 of appropriate length is twisted to provide an axle for receiving impeller segments 34-44. Each of the impeller segments 34-44 are identical and thus the same mold is used to make all the segments. To assemble the impeller, segments 34-44 are slid over the twisted flat wire 45 and the angle of the segments with respect to each other is provided by the twist in the flat wire itself. The drive wheels 30 and 31 are then slid onto the ends of the twisted flat wires. Drive wheel 30 is preferably molded plastic, and includes a channel which receives an axle carried by the chassis of the mechanical sweeper. Drive wheel 31 is preferably molded plastic and has an axle which is received by a channel carried by the chassis of the mechanical sweeper. The impellers are most preferably made from a material which is non-marring, is non-migrating, and will not react with chemicals used for cleaning floors in commercial and residential settings. One material which may be advantageously used is Santaprene 201-55, which is a fully vulcanized polyolefinic material which has a hardness of 55 on the Share A scale, is colorable, and most preferably has a color concentrate added thereto Thus, the impeller segments will not damage the surface which is being cleaned when paddles move across or rest thereon Axle 45 may be brushed aluminum or painted steel flat-wire. 
     Impeller 25 is assembled in the same manner as impeller 24. Segments 46-56 are slid over a twisted flat wire axle. Drive wheels 57 and 58 are then slid onto the ends of the twisted flat wire axle. Drive wheel 57 includes a channel which receives an axle carried by the chassis of the sweeper, and drive wheel 58 has an axle which is received in a channel carried by the chassis of the mechanical sweeper. 
     Thus, it can be seen that an impeller is disclosed which is easy to manufacture, and thus can be provided at a relatively low cost. Additionally, the impeller includes impeller segments which have paddles providing a significant amount of lift and throwing force which will propel debris into the debris receptacle used therewith. 
     The above description is considered that of the preferred embodiment only. Modifications of the invention will occur to those who make or use the invention. Therefore, it is understood that the embodiments shown in the drawings and described above are merely for illustrative purposes and are not intended to limit the scope of the invention which is defined by the following claims as interpreted according to the principles of patent law.