You are an expert at summarizing long articles. Proceed to summarize the following text:

You are an expert at summarizing long articles. Proceed to summarize the following text: 
FIELD OF THE INVENTION 
       [0001]    The present invention relates to mechanized sweepers. Particularly, sweepers used for sweeping paved areas, roads, paved motor vehicle parking lots, parking areas, parking structures and debris covered surfaces. More particularly, the invention relates to the flaps on the hood of the mechanized sweeper. 
       BACKGROUND OF THE INVENTION 
       [0002]    Various types of sweepers are used in sweeping paved surfaces. For example, truck mounted sweepers sweep highway and roadway surfaces. In general, pavement sweepers include a standard truck or specially designed chassis upon which the sweeper unit is mounted. Three basic categories of sweeper units are: re-circulating air sweeper, mechanical sweeper, and vacuum air sweepers. Generally, re-circulating air sweeper units include a motor driven fan, sweeping hood, a curved brush, and a debris separation hopper. The curb brush brings the debris into the path of the sweeping hood. The fan re-circulates airflow from the hopper through the sweeping hood and back into the hopper where dust, particles, and other debris are removed from the airflow by known separation techniques. 
         [0003]    In re-circulating air sweepers, the sweeping hood is prone to maintenance from wear and damage. For example, the sweeping hood extends outside the wheel base and may hit objects that the truck otherwise avoids. Particularly, when the truck is cleaning parking lots and parking structures, it is also more likely the hood may hit curbs and support structures within the parking area. Exacerbating this problem, because debris may tend to clump in corners, drivers are forced to drive deep into the corners and near the curbs and support structures which further increases the likelihood of damage from hitting objects. In order to fix the damaged hood, the entire hood must be removed from under the sweeper in a labor and time intensive procedure. 
         [0004]    In addition to damage, the hoods are subject to wear. The hoods include a series of rubber flaps that allow for debris to pass under the hood and be trapped until the re-circulating air may lift the debris into the hopper. The flaps extend to the ground so that the debris may be directed toward the hopper by the re-circulating air. As the sweeper moves through the parking lot, the flaps wear against the pavement. As the flaps wear against the ground, the flaps lose material. Once the material is lost from the flaps, then the hood is no longer able to contact the paved surface at the same hood height. If the flaps do not contact the surface, then the air that is re-circulated under the hood is no longer directed toward the hopper. Instead, the re-circulated air may flow out from underneath the hood and push debris out from the hood back onto the pavement. 
         [0005]    In order to alleviate these problems, the driver generally employs one of two methods. The driver may lower the entire hood, or the driver may replace the rubber flaps. Replacing the rubber flaps requires removing the entire hood from under the sweeper and setting the flaps into the sweeper hood. By replacing the flaps, the hood height is maintained according to the original configuration. Alternatively, the driver may lower the hood so that the rubber flaps again contact the paved surface. Lowering the hood changes the dynamics of the hood. As the hood is lowered, the path of the re-circulating air changes in cross-sectional size. The decreased cross-sectional size requires higher air velocity to maintain the same flow rates. Higher flow rates changes the size of the debris that may be removed, such that larger debris will no longer be picked up by the re-circulating air flow. Therefore, the driver must decide between incomplete sweeping from a lowered hood or increased downtime from constantly replacing flaps. 
       SUMMARY OF THE INVENTION 
       [0006]    An aspect of the invention provides a hood for a mechanized sweeper. The hood comprises an upper surface, an adjustable front flap, an adjustable rear flap, and end skirts. The adjustable front flap is configured to extend perpendicularly downward from the upper surface. The adjustable rear flap is configured to extend perpendicularly downward from the upper surface. The end skirts are configured to extend perpendicularly downward from the upper surface and further configured to extend perpendicular from the front flap and the rear flap such that the adjustable front and rear flaps are adjusted to maintain a depth equal to the depth of the end skirts. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a diagram of a re-circulating air sweeper; 
           [0008]      FIG. 2  is a view of the hood of the sweeper of  FIG. 1 ; 
           [0009]      FIG. 3  is another view of the hood of the sweeper of  FIG. 1 ; 
           [0010]      FIG. 4  is an expanded view of the hood of  FIG. 1 ; 
           [0011]      FIG. 5  is a view of a front flap of the hood of  FIG. 1 ; 
           [0012]      FIG. 6  is a view of a cartridge flap of the hood of  FIG. 1 ; and 
           [0013]      FIG. 7  is a view of the hood including connections to the sweeper. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0014]    Turning now to the drawing figures,  FIG. 1  is a diagram of a re-circulating air sweeper  10 . The sweeper  10  includes a cab  12 , a fan  14 , a motor  16 , a sweeping hood  18 , a curb brush  20  and a hopper  22 . The sweeper  10  is generally a specialized vehicle supported on four tires  26  and mounted on a standard utility truck chassis. As the sweeper  10  moves down a road, debris and trash under the hood  18  passed through a flexible hose  28  to the hopper  22  for collection. The brushes  20  in front of the hood  18  rotate and push debris into the path of the hood  18 . The fan  14  blows air through one side of the hood  18 . The air is then returned to the hopper  12  through the flexible connecting member  28 . In this embodiment, the fan is located on the passengers side and the return is located on the driver&#39;s side of the vehicle  10 . Having the return  28  on the driver&#39;s side allows for a driver to better align the portion of the hood  18  under the return  28  with trash and debris that is moving under the driver and along the curbs. However, reversing the position of the fan and the return such that the fan  14  is on the driver&#39;s side and the return  28  is on the passenger&#39;s side may also effectively remove debris and trash from the surface. 
         [0015]    The fan  14  is powered by the motor  16 . An intake  30  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. 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. 
         [0016]    Turning now to  FIG. 2 ,  FIG. 2  is a view of the hood  18  of the sweeper  10  of  FIG. 1 . The hood  18  includes a left section  30 , a right section  32 , a central mating section  34 , and a front flap  36 . The left and right sections  30  and  32  are generally similar in shape and size. The left and right sections  30  and  32  are mirror images of one another along a central axis across the central mating section  34 . The left and right sections  30  and  32  include a generally rectangular elongated top surface  40  and a skirt end  42 . The skirt end  42  is generally perpendicular to the elongated top surface  40  extending downward from the top surface  40  and extending parallel to the short axis of the elongated top surface  40 . The left and right sections  30  and  32  also include sweeper connections  46  for connecting the hood  18  to the sweeper. Opposite the skirt end  42 , at the other end of the top surface  40  along the long axis of the top surface  40 , mating structures  50  are configured to attach the sections  30  and  32  to the central mating section  34 . 
         [0017]    The central mating section  34  attaches the left and right sections  30  and  32  to each other through the central mating section  34 . The central mating section  34  allows for each side section  30  and  32  to be removed individually from the hood  18 . In a single piece hood, the entire hood would need to be removed to repair any damage to a section. 
         [0018]    The central mating section  34  is configured to overlay portions of the side sections  30  and  32 . The central mating section  34  and the side sections  30  and  32  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 so that forces exerted on the side sections  30  and  32  do not damage the side sections  30  and  32 , instead damaging a simple connector. The sections, then, are relatively flexible to direct impacts while maintaining stiffness in normal operating conditions. 
         [0019]    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. 
         [0020]    The front flap  36  of the hood  18  extends over the elongated top surface  40  of the left and right portions  30  and  32  and the central mating section  34  and extends perpendicularly downward as deep as the end skirt  42 . An outer edge  50  of the front flap  36  abuts the end skirt  42 . The end skirt  42  and the front flap  36  are the lower extension of the hood  18 . Together with a back flap (discussed with reference to  FIG. 3  below), the front flap  36  and the end skirts  42  form a plenum under the elongated top surface  40  of the side portions  30  and  32  and the central mating section  34 . The plenum is the chamber under the hood  18  through which the air flows from the fan  14  through the flexible hose to the hopper. 
         [0021]    The plenum is ideally a constant volume chamber. When the end skirts  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 depth of the end skirts  42 . A constant volume chamber allows for a constant airflow through the plenum. 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, then in order to move the same amount of air that enters through the fan requires an increased velocity of the air as it flows through the plenum. Bernoulli&#39;s principle requires that as the air moves faster, the pressure drops. A drop in pressure limits the size and weight of the debris removed from the paved surface. 
         [0022]    The front flap  36  and the end skirts  42  also must abut the paved 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 . If the front flap does not reach the pavement, then air may escape under the hood  18  over the paved surface. Escaping air may push debris away from the hood  18  and also limits the ability of the air to push the debris under the hood  18  through the flexible hose  28 . 
         [0023]    The front flap  36  is flexible such that debris that hits the front flap  36  lifts the flap  36  so that the debris may enter the plenum for collection. However, as the front flap  36  hits the pavement, wear removes parts of the front flap  36  so that the flap does not touch the pavement. The front flap  36  is configured so that the flap may be lowered relative to the hood  18 . Slotted connectors  60  attach the front flap  36  to the hood  18 . The slotted connectors  60  are received through a slot (as shown in  FIG. 5 ) in the front flap  36  and are threaded into the hood  18 . As the connector  60  is tightened, the front flap  36  is compressed and locked in place between the connector  60  and the hood  18 . The compressed front flap  36  then does not move relative to the hood  18 . When the connectors  60  are loosened, then the front flap  36  may be moved relative to the hood  18 . As the front flap  36  is worn, the connectors  60  may be loosened and the front flap  36  may be extended so that the front flap  36  becomes flush with the pavement. Thus, instead of replacing the entire front flap  36 , or being forced to lower the hood  18 , the length of the front flap  36  may be adjusted to maintain the space under the hood  18  and maintain the contact with the pavement. 
         [0024]      FIG. 3  is another view of the hood  18  of the sweeper  10  of  FIG. 1 . The view of  FIG. 3  is a side view, with the end skirt removed. The hood  18  includes a rear cartridge flap  64 . The hood has been described above. The rear cartridge flap  64  extends perpendicularly downward from the elongated upper surface  40 . The cartridge flap  64  abuts the ground at the rear part of the hood  18 . The cartridge flap  64  attaches to the hood  18  by rear connectors  70 . The rear connectors  70  are threaded into the cartridge flap  64  and the hood  18 . As the rear connectors  70  are progressed downward, the rear cartridge flap  64  is lowered toward the ground. 
         [0025]    Similar to the 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. 
         [0026]    The cartridge flap  64  includes a rigid member to attach to the rear connectors  70 . The rigid member is formed from an upper U-shaped member  66  and a downward projecting straight support member  68 . The upper U-shaped member  66  is inverted such that the horizontal part of the U-shaped member may receive the rear connectors  70 . The U-shaped member  66  is rigidly attached to the straight member  68 . The straight member  68  extends downward to shorten the distance to the flexible portion of the flap. In the rear of the hood, it may be beneficial to have a slightly stiffer flap than in the front of the hood. While debris is meant to push under the front flap, the debris is not meant to roll out from underneath the hood at the rear. 
         [0027]      FIG. 4  is an expanded view of the hood of  FIG. 1 . The hood  18  includes the left section  30 , the right section  32 , the central mating section  34 , the front flap  36 , the rear cartridge flap  64 , a support bar  74 , and an interior flap  76 . The support bar  74  extends along the long axis of the hood  18  between the end skirts  42 . The bar receives the slotted connectors  60 . The front flap  36 , then, is compressed upon the support bar  74  so that the front flap  36  may be fixed, but include adjustability by relieving the pressure on the front flap  36  by reversing the slotted connectors  60 . 
         [0028]    The interior flap  76  is located behind the front flap  36 . The interior flap  76  acts as a 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 interior flap  76  maintains contact with the pavement. Once the debris passes the front flap  36 , then the front flap  36  falls back into contact with the pavement. As the debris passes the interior flap  76 , the front flap  36  maintains contact with the pavement and the plenum under the hood  18 . 
         [0029]      FIG. 5  is a view of the front flap  36  of the hood  18  of  FIG. 2 . The front flap  36  includes slots  80 . The slots  80  are configured to receive the slotted connectors of the hood. The slots  80  are configured so that the front flap  36  may be slidably advanced relative to the hood so that the front flap  36  may maintain contact with the paved surface. A lower edge  82  of the front flap  36  is the lowermost projection of the front flap  36 . This edge  82  is worn on the pavement as the flap  36  contacts the pavement. 
         [0030]    The slots  80  in the flap  36  also allows for more of the flap  36  to be used prior to removing the flap  36 . The flap  36  may be lowered a distance equal to the length of the slot  80 . Thus, the edge  82  of the flap  36  may be worn away for a distance equal to the length of the slot  80 . This reduces the environmental impact of the wasted portion of the front flap  36 . 
         [0031]    Increasing the total length of the flap  36  may also increase the life of the front flap  36 . As debris contacts the front flap, the additional rubber that is flexed over the upper surface of the hood may absorb some of the impact from the debris. Thus, more of the flap  36  may be used and the wear of the flap  36  may be reduced. 
         [0032]      FIG. 6  is a view of the cartridge flap  64  of the hood  18  of  FIG. 3 . The cartridge flap  64  includes a cartridge  86  and a flexible rubber member  88 . The cartridge  86  is configured to receive rear connectors  70  to set the depth of the rear cartridge flap  64  over the pavement. The cartridge  86  is also configured to receive the rubber member  88 . The rubber member  88  is the flexible portion of the rear flap  64 . 
         [0033]    As the cartridge flap  64  is lowered, the rubber member  88  maintains contact with the pavement. The use of the cartridge  86  allows for minimal rubber use in the rubber member  88 . Because the cartridge  86  (and thus the rubber member  88 ) may be lowered to the depth of the rear connectors  70 , the waste rubber in the rubber member  88  is minimized. 
         [0034]    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 .  5  Turning now to  FIG. 7 ,  FIG. 7  is a view of the hood  18  including connections to the sweeper. The hood  18  is configured to attach to the sweeper. Hood connectors  46  include brackets configured to receive connecting members from the sweeper. The connecting members include connecting arms and a connecting piston  96 . The connecting arms are connected to the hood connectors  46  at the hood  18 . The connecting arms allow the hood  18  to rotate relative to the sweeper while still supporting the hood  18 . 
         [0035]    The connecting arms are also pinned to the sweeper. The connecting arms are shaped such that forces that lift and drop the hood  18  are appropriately transmitted through the connecting arms. The connecting arms are also formed to deform when forces are exerted on the 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 deformable to impacts from debris to the hood  18 . This allows a simple connecting arm, instead of the hood portions, to be replaced. 
         [0036]    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 . 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. The controls for the piston  96  are 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 is unable to be swept under the front flap  36  of the hood  18 . Lighter, larger debris may not be pushed under the hood  18  like most debris because the larger debris requires more force to be pushed under the hood  18 . When the debris is not pushed under the hood, the debris may build up in front of the hood  18 . A build up in front of the hood limits the effectiveness of the sweeper in sweeping debris. 
         [0037]    When the operator engages the piston, the piston length shortens and the hood  18  is raised. The operator may 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. 
         [0038]    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 . 
         [0039]    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.

Summary:
A hood for a mechanized sweeper comprises an upper surface, an adjustable front flap, an adjustable rear flap, and end skirts. The adjustable front flap is configured to extend perpendicularly downward from the upper surface. The adjustable rear flap is configured to extend perpendicularly downward from the upper surface. The end skirts are configured to extend perpendicularly downward from the upper surface and further configured to extend perpendicular from the front flap and the rear flap such that the adjustable front and rear flaps are adjusted to maintain a depth equal to the depth of the end skirts.