Patent Application
20080083084
Turning now to the drawing figures,
The fan 14 is powered by the motor 16. An intake 21 of the fan 14 pulls air from the hopper 22, pushes the air through a hood entry and passes the air through the hood 18 back through the return 28 into the hopper 22. Within the hopper 22, a filter filters the air prior to passing the air through the intake 21. In this manner, the air that enters the fan 14 is filtered from small debris which may have been picked up through the air if the intake was vented to atmosphere. The motor 16 is configured to power the re-circulating air sweeper system, but is not responsible for propulsion of the sweeper 10. However, fluid reservoirs meant to supply both the motor 16 and the engine of the sweeper 10 may be shared between these two components.
Turning now to
Opposite the skirt end 42 on left section 30, at top surface 40 along its long axis, mating structures 50 are configured to connect sections 30 and 32 via central mating section 34. Therefore, as may be seen, central mating section 34 attaches the left and right sections 30 and 32 to each other. The central mating section 34 also allows for each side section 30 and 32 to be removed individually from the hood 18 as opposed to a single piece type hood where the entire hood would need to be removed to repair any damage to the hood.
The central mating section 34 is configured to overlay portions of the side sections 30 and 32 and are connected so that the hood 18 is structurally stiff. However, the connectors 50 between the central mating section 34 and the side sections 30 and 32 may be configured to shear forces exerted on the side sections 30 and 32 such that damage does not occur to side sections 30 and 32, but instead cause damage to a simple connector. The sections, then, are relatively resilient to direct impacts while maintaining stiffness during normal operating conditions.
If a side section 30 or 32 is damaged, then repair may be achieved quicker and more cost effectively by having to only replace a single side portion 30 or 32. Access to a single side portion 30 or 32 is less labor intensive than fully removing the entire hood. In addition, replacing only a single side section 30 or 32 does not require removing additional connections between the hood 18 and the sweeper. Moreover, the lower costs associated with shipping smaller parts at less weight also reduce the total cost of maintenance.
As more clearly shown in
As shown in the figures, flap 36 is held in stationary position by bracket rod 74 relative to middle flap 76, which is fixed. Fasteners 60 may be loosened and moved rearward within the slot 35 formed in portions 31,33 to allow flap 36 to fall vertically under its own weight, thereby lengthening flap 36. Since flap 76 is raised slightly relative to flap 36, debris flows relatively easily under hood 18 from the front. Rear flap 64 is longer relative to middle flap 76, but typically of equal vertical height with flap 36. Flaps 64, 76 and 36, in conjunction with end skirts 42 and 42′ form a vacuum plenum into which debris on the pavement are swept through forward motion of sweeper 10 and brooms 20. “Vacuum plenum” is hereby defined as the volume of space defined under the hood 18 into which road debris is swept and within which air is held a pressure less than ambient atmospheric pressure during operation of said sweeper 10.
The vacuum plenum is ideally a constant volume chamber. When the end skirts 42, and 42′ abut the ground, the volume of the plenum is approximately the product of the length and width of the elongated top surfaces 40 and the height of the end skirts 42. A constant volume chamber allows for a continuous airflow through the plenum at a known negative pressure. As air enters the plenum from the fan 14, an equal amount of air exits the plenum through the flexible hose 28. At each cross section parallel to the end skirt 42 through the plenum, an equal amount of air travels. If the cross section parallel to the end skirt 42 is reduced in size, an increased velocity of air must flow through the plenum in order to move the same volume of air entering and discharging through fan 14. In accordance with Bernoulli's principle, as air moves faster, the pressure drops across a surface. A drop in pressure, therefore, determines the size and weight of the debris removed from a road paved surface as the sweeper 10 traverses over a paved road surface.
Based on these principles, front flap 36 and the end skirts 42 must abut the paved road surface so that air does not flow out from under the hood 18. The front flap 36 and the end skirts 42 direct flow of air from the fan to the flexible hose 28 and if the front flap does not reach the pavement, air will escape under the hood 18 over the paved surface. Escaping air may even push debris away from the hood 18 further limiting the ability of the air to bring debris under the hood 18 and into flexible hose 28.
The front flap 36 is flexible such that debris hitting the flap deform its leading edge rearward so that the debris may enter the plenum for collection. However, due to road surface irregularities, front flap 36 contacts the pavement and losses material due to wear. Over time the flap does not fully contact the pavement and the volumetric efficiency of the hood 18 is reduced. To counteract this wear, front flap 36 is configured so that the flap may be lowered relative to the hood 18. Connectors 60 attach the front flap 36 to the hood 18 and are received through a slot 35 and a corresponding slot 80 (see also
The hood 18 also includes a rear cartridge flap 64 which extends vertically downward from the upper surface 40 and abuts the pavement at the rear part of the hood 18. Cartridge flap 64 is supported by hood 18 via rear connectors 70. Rear connectors 70 are threaded into the cartridge flap 64 and the hood 18 such that as rear connectors 70 are rotated, the rear cartridge flap 64 may be lowered toward the ground.
The cartridge flap 64 includes a rigid member 86 to attach it to rear connectors 70. The rigid member 86 is formed from an upper U-shaped member and a downward projecting straight support member. The upper U-shaped member is inverted such that the horizontal part of the U-shaped member may receive the rear connectors 70, and is rigidly fixed to the underside of the hood 18. A straight resilient member 88 extends downward a short distance from member 86 to contact the pavement and is flexible. While flap 36 tends to flexibly deform to allow pavement debris to enter underneath hood 18, rear flap 64 is stiffer to avoid debris rolling out rearward from underneath hood 18.
In a fashion similar to front flap 36, the purpose of the rear cartridge flap 64 is to maintain the depth of the hood 18 and maintain contact between the hood 18 and the pavement. As the rear cartridge flap 64 is worn away from contact with the pavement, the rear connectors 70 may be advanced so that the bottom edge of the rear cartridge flap 64 may maintain contact with the pavement without having to drop the hood 18 downward. Slots 87 are formed in member 86 to allow the fixing of flap 64 against a rear trailing portion of hood 18 with fasteners 85, while allowing its lowering thereof.
The interior middle flap 76 is located behind the front flap 36. The middle flap 76 acts as a volumetric check valve for the plenum. As debris passes the front flap 36, the circulating air under the hood may not escape because the air flows between the interior flap 76 and the rear cartridge flap 64. As the debris passes the front flap 36, the front flap falls back into contact with the pavement and the interior flap 76 maintains close proximity with the pavement and the integrity of the plenum under the hood 18 is thereby maintained.
Increasing the total length of the flap 36 also increases the life of the front flap 36. As debris contact the front flap, the additional rubber that is flexed over the upper surface of the hood absorbs some of the impact from the debris. Thus, more of the flap 36 may be used to engage debris and the wear of the flap 36 is reduced.
The use of the cartridge 86 allows for minimal rubber use in the rubber member 88, because cartridge 86 (and thus the rubber member 88) may be lowered to a desired depth via rear connector 70, such that sufficient height is maintained above the pavement while maintaining sufficient volumetric integrity of the plenum over the pavement.
As may be seen, the cartridge 86 is coupled to the rubber member 88 through a plurality of connectors 89 located along the length of the cartridge flap 86 and the rubber member 88. In another embodiment, the cartridge 86 may slidably receive the rubber member 88 laterally, for example through a dove tail joint between the cartridge 86 and the rubber member 88. The rubber member 88, then, would be supported in the hood by the cartridge 86 and held in place laterally by the end skirts of the hood. In another embodiment, the rubber member 88 may be attached to the cartridge 86 by a compression member exerting a force to squeeze the rubber member 88 to the cartridge 86. The compression member is configured to fixedly attach the rubber member 88 to the cartridge 86. Because the rear flap 64 may be more rigid than a front flap, the length of the cartridge may be elongated to increase stiffness. Increased stiffness may come at the expense of more frequent replacement, as the rubber member 88 is likely to wear faster and the amount the flap may be lowered is limited to the depth of the rubber member 88.
Turning now to
The connecting arms are also pinned to the sweeper, but are shaped such that forces that lift and drop the hood 18 are appropriately transmitted through the connecting arms. The connecting arms are made to deform when forces are exerted on hood 18 that attempt to rotate the hood 18 over the pavement. The connecting arms, then, are the portion of the sweeper that is most susceptible to damage due to impacts from debris to the hood 18. This allows a simple connecting arm, instead of the hood portions, to be replaced upon the occurrence of damaging impacts.
The hood 18 is also connected to the sweeper through a piston 96. The piston 96 attaches to two pulleys 98 through guide wires 100, and mounting brackets 102 attach the pulleys to the sweeper. The guide wires 100 are attached to the hood 18 through a pair of eye bolts 110. The piston 96 is configured to quickly lift the hood off the pavement with controls for the piston 96 located within the cab of the sweeper so that the operator may lift and lower the hood from within the cab while operating the sweeper. By popping the hood up, the operator may be able to clear larger, lighter debris that are unable to be swept under the front flap 36 of the hood 18. Lighter, larger debris are more difficult to ingest under hood 18 than other debris because larger debris require more force to be pushed under the hood 18. When debris cannot transit under the hood, the debris builds up in front of the hood 18 and limits the effectiveness of the sweeper. When the operator engages the piston, the piston length shortens and the hood 18 is raised. The operator may thereby keep the hood 18 raised as the operator drives over the debris so that the debris is swept under the hood 18. When the hood 18 is simply kicked up, then the debris is funneled between the interior flap and back flap of the hood 18 and may be removed from the paved surface into the hopper. This saves time and labor where an operator previously would be required to push debris from the front of the hood 18 after stopping the sweeper and laboring in front of the hood 18 to remove the debris.
While the piston 96 has been attached to the hood 18 through guide wires, it may be possible to directly couple the piston 96 to the hood 18. Moreover, it may be possible to provide the same effect through other means besides a piston. For example, a four bar linkage, a motor, or a screw drive may raise the hood 18 in order to clear debris from the front of the hood 18.
As will be apparent to one skilled in the art, various modifications can be made within the scope of the aforesaid description. Such modifications being within the ability of one skilled in the art form a part of the present invention and are embraced by the claims below.
