Sweeping machine with movable recirculation flap

Abstract: A sweeping machine has a chassis (10), wheels (26) for supporting the chassis and a brush (30) mounted on the chassis for rotation to throw debris over the brush and into a debris hopper (32) mounted on the chassis behind the brush. There is a control lever (20) on the chassis for raising and lowering the brush relative to a surface to be swept. As the brush wears, a recirculation flap (54) is positioned between the brush (30) and the debris hopper (32) and located closely adjacent a rear portion of the brush to direct debris not reaching the debris hopper forwardly toward the brush sweeping zone. The recirculation flap (54) is moved toward and away from the brush concurrently with movement of the brush toward the surface being swept as the brush wears, whereby the space between the rear portion of the brush (30) and the recirculation flap (54) remains relatively constant.

Description: The present invention relates to sweeping machines and more specifically to what are known in the art as over-the-top sweepers. In such machines, the main sweeping brush throws debris up and over the top of the brush into a debris hopper behind the brush, rather than throwing debris directly forward into a hopper in front of the brush in what is known as a forward throw sweeper. Especially, the present invention relates to a movable recirculation flap which is positioned between the rear periphery of the brush and the debris hopper. Conventional over-the-top sweepers have what is known as a recirculation flap which slopes down and forward at about a 45-degree angle and is located immediately behind the main brush and between the rear periphery of the brush and the debris hopper. All sweepers tend to throw some debris over the brush. This debris would drop to the floor behind the brush and be lost, except that the recirculation flap directs it forward into the sweeping zone of the brush, so it will be swept up a second time and loaded into the hopper. A forward throw sweeper throws only a small part of the total debris over the brush, but an over-the-top sweeper throws all of it over the brush, and a percentage of such debris will drop between the brush and the front wall of the hopper. Thus, an effective recirculation flap is very important in an over-the-top sweeper. Normally, it is important to maintain a small clearance on the order of 6.125mm (1/4") or so between the rear periphery of the brush and the recirculation flap. It is also important to maintain this clearance as the brush wears down to a smaller diameter. In a particular size sweeper, a new brush may have a 269.5mm (11") diameter and the brush is considered to be worn down to an extent for replacement when its diameter is 196mm (8"). As this wear occurs, the clearance between the brush and a fixed recirculation flap will inevitably increase, which will dramatically reduce the sweeping efficiency of the machine. The present invention solves this problem by having a movable recirculation flap, which recirculation flap is moved concurrently with adjustment of the position of the brush relative to a surface to be swept. The main sweeping brush is mounted between a pair of brush arms which are pivotally mounted on the machine chassis. The brush arms are moved by a control lever accessible to the operator. Thus, the operator can control the position of the brush relative to the surface it is sweeping. Mounted on one of the brush arms is a lever which is in contact, through an intermediate lever, with an arm that extends out from the pivotal recirculation flap. The result of the interconnection described is that movement of the brush toward and away from a surface to be swept provides concurrent movement of the recirculation flap toward and away from the rear periphery of the sweeping brush, to the end that the gap between the brush and the recirculation flap remains essentially constant. A previously proposed sweeping mechanism is described in US-A-3,093,853 in which there is a power sweeper broom chamber with an extension close to the downward travel path of the broom, the lower part of which is flexible to accommodate sudden deflection due to obstacles. A further previously proposed sweeping mechanism is described in AU-B-29608/89 in which there is described an industrial sweeping apparatus with a flexible back skirt. The present invention relates to sweeping machines of the type known as over-the-top sweepers and especially to a movable recirculation flap for such a machine. A first aim of the present invention is to provide a recirculation flap for use in the described environment which is moved concurrently with adjustment of brush position relative to the surface being swept. A further aim of the present invention is to provide an over-the-top sweeper having a movable recirculation flap which moves concurrently with brush adjustment to maintain an essentially constant gap between the flap and the rear of the sweeping brush. A further aim is an over-the-top sweeper having a manual control to adjust brush position relative to the surface being swept, which manual control simultaneously moves a recirculation flap immediately behind the brush to maintain a constant flap/brush gap. Accordingly the present invention is directed to a sweeping machine as described in Claim 1. Advantageous further features are described in sub-claims 2 to 8. An example of a sweeping machine made in accordance with the present invention will now be described in relation to the accompanying drawings, in which: Figure 1 is a side view, with portions broken away, of an over-the-top sweeping machine; Figure 2 is an enlarged partial side view illustrating the main sweeping brush and the mechanisms for moving the front flap and recirculation flap; Figure 3 is an enlarged partial side view, similar to Figure 2, showing the recirculation flap in a second position; Figure 4 is an exploded perspective illustrating the foot pedal and its connection to the front flap; Figure 5 is an enlarged side view illustrating the foot pedal and the front flap in a partially raised position; and Figure 6 is a side view, similar to Figure 5, illustrating the foot pedal and front flap in a full raised position. The present invention relates to sweeping machines and especially to what is known in the art as an over-the-top sweeper in that the debris is moved over the top of the brush as it transfers to the debris hopper which is located behind the brush. In Figure 1, the sweeper includes a chassis 10 having a front control module 12 mounting a steering wheel 14 and a control lever 16. There is an operator seat 18 and a control lever 20 for use in changing the position of the sweeping brush relative to the surface being cleaned. A foot pedal 22 is pivotally mounted, as at 24, to the chassis 10, as will be described in more detail hereinafter. The chassis 10 is mounted on wheels 26 and may include front side brushes 28 and a main sweeping brush 30. Directly behind the brush 30 is a debris hopper 32. The brush 30 will have a conventional drive mechanism, not shown herein, but common on machines of this type. The main sweeping brush 30 is mounted for rotation between a pair of arms, one of which is indicated at 34. Each of the arms 34 will pivot about a pivotal mounting 36. The two arms are joined together in a torsionally rigid manner by a cross bar indicated at 37, and suitable fasteners, not shown. One arm 34 is attached to a link 38 by means of a fastener 40, midway of the link 38, and a fastener 42 at the lower end of the link 38, with the fastener 42 being located in an elongated slot 44. The upper end of link 38 is pivotally attached to an arm 46, which in turn is pivotally attached to the control lever 20. The lever 20 pivotally mounts the arm 46 intermediate its opposite ends, as at 48, and the lever 20 is pivotally attached to the chassis 10, as at 50. Thus, as shown in Figure 2, pivotal movement of the lever 20 counterclockwise about its pivot point 50 has the effect of rotating the brush arms 34 about pivot point 36 in a counterclockwise sense. This movement is necessary to lower the brush as it becomes worn. Conventionally, sweeping brushes may wear from a 269.5mm (11") new diameter to a 196mm (8") worn diameter before the brush is discarded. In order to maintain the brush at the proper orientation relative to the surface to be cleaned, it is periodically lowered by the operator through manipulation of the lever 20. The above-described mechanism controls movement of the brush so that it is maintained in the proper location for sweeping. Over-the-top sweepers throw all of the debris moved by the brush over the top of the brush and a percentage of such debris will drop between the brush and the front wall of the hopper. This dictates that a recirculation lip or flap be located directly behind the brush and that there be minimal clearance between the brush and the recirculation flap. Such clearance is preferably on the order of 6.125mm (1/4") and must be maintained even when the brush is worn to a smaller diameter. The entrance into the debris hopper 32 is indicated at 52 and it is directly behind the brush 30. The recirculation flap is indicated generally at 54 and is located below and to the rear of the brush 30. The flap 54 is made of a rubber or rubber-like material and has two side walls, one of which is indicated at 58. Flap 54 is attached to a support plate 60 by bolts and a retainer strip 61. Plate 60 is bolted to a second support plate 63, which has a round rod 62 welded along its upper edge. A "living hinge" 65, made of flexible rubber or rubber-like material, extends along support plate 63 and contributes to sealing the area against dust leakage. Rod 62 is journaled in portions of chassis 10, and the recirculation flap assembly as described here can pivot about it. Rod 62 includes a bent end 64 which extends upwardly and forwardly and is in contact with a T-shaped lever 68. The lever 68 is pivoted, as at 70, to a portion of the chassis 10 and has an upper end 72 in contact with an arm 74 which is bolted, as at 76, to the brush support arm 34. Figure 2 illustrates the relationship of the recirculation flap 54 and the brush 30 in a position in which the brush is new and it is at its full unused diameter. As the brush is worn, it will be periodically rotated about pivot point 36 so that it maintains a proper relationship to the surface being swept. Figure 3 illustrates the brush in such a moved position. As the brush is pivoted about point 36 by movement of control lever 20, the arm 74, which is attached to the brush support arm 34, will also rotate in a counterclockwise sense. Movement of arm 74 will cause lever 68 to rotate in a clockwise direction, with the difference in position of this lever being shown by a comparison of Figures 2 and 3. As lever 68 moves in a clockwise direction, a lower portion thereof, indicated at 78, will cause counterclockwise movement of the arm 64 of rod 62. This in turn will pivot the recirculation flap in a counterclockwise sense so that it will maintain its proper orientation relative to the outer circumference of the brush 30. The difference in flap positions between Figs. 2 and 3, and the difference in brush positions in the same two figures, illustrates the related movement of the brush and the recirculation flap brought about by the combination of arm 74 attached to the brush support arm 34, the pivotal lever 68, and the rod 64 which is attached to the recirculation flap 54.

Claims: A sweeping machine including a chassis (10), wheels (26) for supporting the chassis (10), a brush (30) mounted on the chassis (10) for rotation in a direction to throw debris over the brush (30) and into a debris hopper (32) mounted on the chassis (10) behind the brush (30), a pair of brush support arms (34) on the chassis (10) for raising and lowering the brush (30) relative to a surface to be swept, a recirculation flap (54) positioned between the brush (30) and the debris hopper (32) and located closely adjacent a rearward portion of the brush (30) and adjacent to the debris hopper (32) to direct debris thrown by the brush (30) and not reaching the debris hopper (32), characterised by a control lever (20) for moving the recirculation flap (54) and the brush (30) relative to each other and relative to the surface to be swept, the flap (54) being movably connected to the brush support arm (34) via a rod (62) and a further lever (68), the rod (62) having an end (64) being in contact with the further lever (68), and the further lever (68) having an end (72) in contact with an arm (74) of the brush support arm (34), whereby movement of the control lever (20) moves the sweeping brush (30) toward and away from the surface to be swept, and whereby movement of the sweeping brush (30) toward and away from the surface to be swept causes concurrent movement of the recirculation flap (54) toward and away from the brush (30) periphery, such that the gap between the rearward portion of the brush (30) and the recirculation flap (54) remains essentially constant as the brush diameter is reduced to wear. A sweeping machine according to claim 1, characterised in that the brush arms (34) are spaced and pivotally mounted on the chassis (10), with the brush (30) being mounted for rotation between the spaced brush arms (34). A sweeping machine according to claim 1 or claim 2, characterised in that the recirculation flap (54) is pivotally mounted on the chassis (10). A sweeping machine according to claim 3, characterised in that the movement of the recirculation flap (54) is a pivotal movement. A sweeping machine according to claim 4, characterised in that the arm (74) extends radially outwards from the brush arm (34), and the further lever (68) is pivotally mounted on the chassis (10). A sweeping machine according to claim 5, characterised in that rotation of the brush support arm (34) moves the further lever (68) on the chassis (10), which rotates the rod (62) to pivot the recirculation flap (54). A sweeping machine according to claim 1, characterised in that the control lever (20) is pivotally mounted on the chassis (10), one of the spaced brush arms (34) being pivotally connected to the control lever (20). A sweeping machine according to any preceding claim, characterised by further including side walls (58) on opposite ends of the recirculating flap (54) to funnel debris thrown by the brush (30) and not reaching the debris hopper (32) toward the brush sweeping zone.

Inventors: BASHAM MICHAEL T, D COSTA JOSEPH F, DURENBERGER DONALD F, BASHAM, MICHAEL T., D'COSTA, JOSEPH F., DURENBERGER, DONALD F.
Applicants: TENNANT CO, TENNANT COMPANY
Application year: 1999
Main classification: E01H1
IPC codes: E01H1