Patent Publication Number: US-9408511-B2

Title: Pick-up head system having a horizontal sealed debris door for a mobile sweeping vehicle

Description:
RELATED APPLICATIONS 
     This application is a non-provisional application claiming priority from U.S. Provisional Patent Application Ser. No. 61/496,410 filed on Jun. 13, 2011, which is herein incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to dustless pick-up head systems for factory, sidewalk and street sweepers, and more particularly to such dustless pick-up head systems that readily maintain full suctioning effectiveness under almost all conditions. 
     BACKGROUND OF THE INVENTION 
     It is known in the prior art to have a substantially sealed rotatable door apparatus on a pick-up head for use with a surface cleaning vehicle, wherein the rotatable door apparatus rotates about a vertical axis. It has been found that with this type of configuration, the effective size of the debris receiving opening whereat the substantially sealed door apparatus is mounted, cannot be less than one-quarter of the width of the pick-up head, inclusive of the size of the substantially sealed rotatable door apparatus. 
     It is an object of the present invention to provide a full-width dustless pick-up head system. 
     It is another object of the present invention to provide a pick-up head system wherein the effective size of the debris receiving opening whereat the substantially sealed rotatable door apparatus is mounted, can be more than about one-quarter the width of the pick-up head. 
     It is another object of the present invention to provide a pick-up head system wherein the effective size of the debris receiving opening whereat the substantially sealed door apparatus is mounted, can be the full width of the pick-up head. 
     SUMMARY OF THE INVENTION 
     In accordance with one aspect of the present invention there is disclosed a novel pick-up head system for use with a surface cleaning vehicle having a fore-aft axis of travel. The pick-up head system comprises a housing having an interior and a suctioning bottom opening defined by a bottom peripheral edge and open in fluid communication and debris transfer relation to the interior, and defining a fore-aft axis; a debris receiving main inlet in the housing, disposed in debris receiving relation with respect to a surface being cleaned, for receiving debris to the housing, and disposed in debris transfer relation to the interior of the housing for receiving debris to the housing; a rotatable door assembly mounted on the housing at the debris receiving main inlet for rotation about a substantially horizontally oriented door pivot axis, for controlling the passage of debris through the debris receiving main inlet; an air flow barrier operatively disposed between the rotatable door assembly and the housing to substantially preclude the passage of air and small debris between the rotatable door assembly and the housing; and a debris outlet in the housing; wherein, in use, as the rotatable door assembly rotates about the horizontally oriented door pivot axis to thereby permit debris to enter the housing through the debris receiving main inlet, the air flow barrier substantially precludes the passage of air and small debris between the rotatable door assembly and the housing. 
     In accordance with another aspect of the present invention there is disclosed a novel sealed door apparatus for use with a dustless pick-up head on a surface cleaning vehicle. The sealed door apparatus comprises a door frame surrounding the debris receiving main inlet; a rotatable door assembly mounted on the housing at the door frame for rotation about a substantially horizontally oriented door pivot axis; and an air flow barrier operatively disposed between the rotatable door assembly and the door frame to substantially preclude the passage of air and small debris between the rotatable door assembly and the door frame. 
     Other advantages, features and characteristics of the present invention, as well as methods of operation and functions of the related elements of the structure, and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following detailed description and the appended claims with reference to the accompanying drawings, the latter of which is briefly described herein below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The novel features which are believed to be characteristic of the pick-up head system according to the present invention, as to its structure, organization, use and method of operation, together with further objectives and advantages thereof, will be better understood from the following drawings in which a presently preferred embodiment of the invention will now be illustrated by way of example. It is expressly understood, however, that the drawings are for the purpose of illustration and description only, and are not intended as a definition of the limits of the invention. In the accompanying drawings: 
         FIG. 1A  is a perspective view of the first preferred embodiment of the pick-up head system according to the present invention mounted on a surface cleaning vehicle; 
         FIG. 1B  is a partially cut-away top plan view of the first preferred embodiment pick-up head system of  FIG. 1A ; 
         FIG. 1C  is a front elevational view of the first preferred embodiment pick-up head system of  FIG. 1A ; 
         FIG. 1D  is a left corner elevational view of the first preferred embodiment pick-up head system of  FIG. 1A ; 
         FIG. 1E  is a side perspective view from underneath of the first preferred embodiment pick-up head system of  FIG. 1A ; 
         FIG. 1F  is a front perspective view from above of the first preferred embodiment pick-up head system of  FIG. 1A ; 
         FIG. 1G  is a front perspective view from the right side of the first preferred embodiment pick-up head system of  FIG. 1A ; 
         FIG. 1H  is a front perspective view from the right side of the first preferred embodiment pick-up head system of  FIG. 1 , and similar to  FIG. 7  except that the raisable and lowerable sealed door assembly is in a raised position; 
         FIG. 1I  is a front perspective view from slightly off-centre to the right of the first preferred embodiment pick-up head system of  FIG. 1A ; 
         FIG. 1J  is a front perspective view from slightly off-centre to the right of the first preferred embodiment pick-up head system of  FIG. 1 , and similar to  FIG. 9  except that the raisable and lowerable sealed door assembly is in a lowered surface engaging position; 
         FIG. 1K  is a bottom plan view of the first preferred embodiment pick-up head system of  FIG. 1A ; 
         FIG. 1L  is an enlarged partial view of the first preferred embodiment pick-up head system of  FIG. 1A ; 
         FIG. 1M  is an enlarged sectional side elevational view of the first preferred embodiment pick-up head system of  FIG. 1A ; 
         FIG. 1N  is an enlarged partial view of a first alternative embodiment of the first preferred embodiment pick-up head system of  FIG. 1A  with the raisable and lowerable sealed door assembly in raised position; 
         FIG. 2A  is a bottom plan view of the second preferred embodiment pick-up head system according to the present invention; 
         FIG. 3A  is a top plan view of the third preferred embodiment pick-up head system according to the present invention; 
         FIG. 4A  is a top plan view of the fourth preferred embodiment pick-up head system according to the present invention; 
         FIG. 5A  is a partially cut-away top perspective view from above of the fifth preferred embodiment pick-up head system according to the present invention. 
         FIG. 6A  is a front elevational view of the sixth preferred embodiment pick-up head system according to the present invention; and, 
         FIG. 7A  is a partially cut-away side elevational view of the seventh preferred embodiment pick-up head system according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Reference will now be made to  FIGS. 1A through 1N , which show a first preferred embodiment of the pick-up head system of the present invention, as indicated by general reference numeral  100 . The pick-up head system  100  is for use with a surface cleaning vehicle  102  for removing dust (including fine particulate matter) and debris (including bottles, cans, leaves, dirt, and so on) from a surface to be cleaned  104 . 
     The first preferred embodiment pick-up head system  100  is for use with a surface cleaning vehicle  102  having a main fan (not specifically shown), and defining a width “W V ” (see  FIG. 1K ) and a generally central fore-aft longitudinal axis of travel “L”, for cleaning a surface to be cleaned  104  and basically comprises a housing  110 , a substantially rigid debris deflecting skirt  108 , a first debris suctioning inlet  140   a , a debris outlet  120 , a substantially hollow interior  119 , a debris passage  130 , and an air supply passage  180  within the housing  110 . The pick-up head system  100 , and particularly the housing  110 , define the generally central fore-aft longitudinal axis of travel “L”. 
     More specifically, the pick-up head system  100  comprises a housing  110  extending between a first end  111  and a second end  112  to define a width “W H ” (see  FIG. 1K ). Preferably the width “W H ” of the housing is greater than three-quarters of the width “W V ” of the surface cleaning vehicle  102 , and also is preferably approximately the width “W V ” of the surface cleaning vehicle  102 . It has been found that having the width “W H ” of the housing  110  approximately equal to the width “W V ” of the surface cleaning vehicle is very beneficial for purposes of full cleaning of the surface to be cleaned  104  and also for precluding damage to the outer ends  111 , 112  of the housing  110 . Such damage can readily occur if the outer ends  111 , 112  of the housing  110  project laterally outwardly past the width of the surface cleaning vehicle  102 . 
     The housing  110  extends substantially transversely to the generally central fore-aft longitudinal axis of travel “L”. The housing  110  has a substantially hollow interior  119  and a suctioning bottom opening  114  defined by a bottom peripheral edge  109 . The suctioning bottom opening  114  is open in fluid communication and debris transfer relation to the substantially hollow interior  119 . Further, the housing  110  has a front wall  115 , a back wall portion  116 , interconnected by a roof portion  118 . Dust and fine particulate on the surface to be cleaned  104  pass under the front peripheral edge portion  109   f  and are suctioned into the substantially hollow interior  119  of the housing  110 . 
     The front wall  115  of the housing has a first sloped portion  115   a  and a second sloped portion  115   b  that are each sloped rearwardly and inwardly towards the debris receiving main inlet  142 . The debris receiving main inlet  142  is disposed in the front wall  115  between the first sloped portion  115   a  and the second sloped portion  115   b , in debris receiving relation with respect to a surface to be cleaned  104 . Further, the housing  110  is substantially “V”-shaped and the debris receiving main inlet  142  is disposed at the vertex of the “V”-shaped front wall  115 . 
     The pick-up head system  100  further comprises a first debris suctioning inlet  140   a  in the housing  110 . The first debris suctioning inlet  140   a  is disposed adjacent the first end  111  of the housing  110  and is for suctioning debris into the housing  110 . The suctioned debris might include larger debris such as bottles, cans, leaves, twigs, and so on, and might also include smaller debris such as dirt, dust, sand, and so on. 
     The pick-up head system  100  also comprises a debris receiving main inlet  142  in the front wall  115  of the housing  110  in debris receiving relation with respect to a surface to be cleaned  104 , for receiving debris into the housing  110 . There is also a door apparatus  150  operatively mounted at the debris receiving main inlet  142 , as will be discussed in greater detail subsequently. Preferably, the sealed door apparatus  150  comprises a substantially sealed door apparatus. 
     The substantially rigid debris deflecting skirt  108  is disposed at the bottom peripheral edge  109  of the housing  110  for interfacing the housing  110  in substantially sealed relation with the surface to be cleaned  104  as the surface cleaning vehicle  102  moves along the surface to be cleaned  104 . Furthermore, the substantially rigid debris deflecting skirt  108  is disposed on the housing  110  in debris deflecting relation, to thereby deflect debris across a surface to be cleaned  104 . 
     Preferably, the substantially rigid debris deflecting skirt is also solid, and is non-curling and non-pliable, or in other words does not curl rearwardly at the bottom when debris is encountered, as prior art skirts must necessarily do. Also related to not curling rearwardly at the bottom when debris is encountered, the substantially rigid debris deflecting skirt is substantially horizontally oriented to help push and deflect debris. The substantially rigid debris deflecting skirt is also gapless, or in other words has no gaps in it for small debris to pass through. 
     The substantially rigid debris deflecting skirt  108  precludes the passage of almost all air (and contaminants therein, such as dust and other fine particulate matter and the like) from escaping out of the housing  110  in the event that a section of the housing  110  has a higher air pressure than the ambient surroundings, which can occur with recirculating air type pick-up head systems, if the seal with the surface to be cleaned is not present. A very small portion of air is suctioned between the substantially rigid debris deflecting skirt  108  and the surface to be cleaned  104  to preclude any dust and other fine particulate matter and the like from escaping from the housing  110 , and also to suction in dust and other fine particulate matter and the like under the substantially rigid debris deflecting skirt  108  at the front wall  115 , which may be created as the substantially rigid debris deflecting skirt  108  at the front wall  115  engages the surface to be cleaned  104 . 
     Furthermore, the substantially rigid debris deflecting skirt  108  precludes the passage of larger debris, such as stones, bottles, cans, leaves, and the like, from passing under the front wall  115  as the housing  100  moves along the surface to be cleaned  104 . Instead, the substantially rigid debris deflecting skirt  108  directs small debris, such as gravel, along the housing  110  to the debris receiving main inlet  142  at the sealed door apparatus  150 . The front wall  115  of the housing directs larger debris to the debris receiving main inlet  142  at the sealed door apparatus  150  due to the right-to-left rearward slant of the housing  110 . 
     Preferably, the substantially rigid debris deflecting skirt  108  is made from UHMW polyethylene or polyurethane, or any other suitable material, to promote sliding of the housing  110  along the surface to be cleaned  104 , as opposed to riding over the debris, thereby breaking the “seal” of the substantially rigid debris deflecting skirt  108  with the surface to be cleaned  104 . Preferably, there are vertical slots (not specifically shown) in the substantially rigid debris deflecting skirt  108  to allow for vertical adjustment (downward adjustment) of the substantially rigid debris deflecting skirt  108  with respect to the housing  110  as the substantially rigid debris deflecting skirt  108  wears. Suitable fasteners would extend through the vertical slots (not specifically shown) and threadibly engage co-operating threaded apertures in the housing  110 . It is also contemplated that a downwardly sprung flap (not shown) could be included to make a seal with the surface to be cleaned  104 . In the event that the substantially rigid debris deflecting skirt  108  temporarily does not “seal” with the surface to be cleaned  104 , such as when the housing  110  travels over a pothole, or the like, or rides up slightly over a sewer grate, or the like, and simply doesn&#39;t have the deflection to seal properly because it is designed to be rigid as a plowing entity. 
     The debris outlet  120  is disposed generally centrally, in a lateral sense, in the housing  110 , immediately rearwardly of the debris receiving main inlet  142 , for permitting dust and debris to egress from the housing  110  into a hopper (not specifically shown). The debris outlet  120  is disposed towards the back wall portion  116  of the housing  110  generally centrally disposed between the first end  111  and the second end  112 . The debris outlet  120  is connected in air flow delivery relation through a delivery duct  121  to a hopper for permitting dust and debris to egress from the housing  110  into the hopper. Preferably, the first debris suctioning inlet  140   a  has a cross-sectional area about one-half the cross-sectional area of the debris outlet  120 . 
     The sealed door assembly  150  of the first preferred embodiment pick-up head system  100  comprises a door frame  145  that surrounds the debris receiving main inlet  142 . Preferably, the door frame  145  has a first side plate  145   a  and a second side plate  145   b , and an arcuate header portion  145   c  defining a center axis “C” disposed substantially horizontally and generally transversely to the fore-aft longitudinal axis of travel “L”. 
     The sealed door assembly  150  of the first preferred embodiment pick-up head system  100  further comprises rotatable door assembly  146  that defines a substantially horizontally oriented central pivot axis “P” and an outer periphery  146   p , and has a wherein the rotatable door assembly has a first side  146   a  and a second side  146   b . The rotatable door assembly  146  is mounted on the housing  110  at the door frame  145 . There is also an air flow barrier seal  147  operatively disposed in sealing relation between the rotatable door assembly  146  and the housing  110 , and more specifically between the rotatable door assembly  146  and the door frame  145 . 
     The rotatable door assembly  146  comprises at least a first door portion  146   a  and a second door portion  146   b , and in the first preferred embodiment, as illustrated, also comprises a third door portion  146   c , a fourth door portion  146   d , a fifth door portion  146   e , a sixth door portion  146   f , a seventh door portion  146   g , an eighth door portion  146   h , and a ninth door portion  146   i  joined together at a substantially horizontally oriented central pivot axis “P” that is substantially transverse to the generally central fore-aft longitudinal axis of travel “L”, and is collinear with the center axis “C” of the arcuate header portion  145   c , and operatively mounted at the central pivot axis “P” in rotatable relation on the housing  110  at the debris receiving main inlet  142 . 
     The air flow barrier seal  147  is operatively disposed between the rotatable door assembly  146  and the door frame  145  for sealing the rotatable door assembly  146  with respect to the door frame  145 , to thereby substantially preclude ingression of air into the substantially hollow interior  119  of the housing  110  through the debris receiving main inlet  142 , as the rotatable door assembly  146  rotates to permit debris to enter the substantially hollow interior  119  of the housing  110 . 
     The first door portion  146   a  has a first side edge  148   a  and a second side edge  148   b  and an end edge  148   c  spanning between the first side edge  148   a  and the second side edge  148   b . Similarly, each of the other door portions has a first side edge and a second side edge and an end edge spanning between the first side edge and the second side edge. In the first preferred embodiment, as illustrated, there are nine door portions  146   a  through  146   i , each the same as the others. Preferably, the end edges are substantially straight to evenly and fully engage a surface to be cleaned  104  such as a street or a parking lot, or the like. 
     Preferably, the air flow barrier seal  147  comprises a sealing flap  147  disposed at the side edge of each of the first door portion  146   a  and the second door portion  146   b  for intermittently contacting a surface to be cleaned  104  in substantially sealed relation as the rotatable door assembly  146  rotates. Since the sealing flaps  147  will typically wear quite readily, the sealing flaps  147  are preferably removable and replaceable, typically by means of suitable threaded fasteners (not specifically shown). The sealing flaps  147  are made from rubber material, a rubber composite material, a synthetic rubber material, or a synthetic rubber composite material, or any other suitable material in order to engage the surface to be cleaned  104  in substantially sealed relation. Preferably, the removable and replaceable sealing flaps  147  have a plurality of vertically oriented slots (not specifically shown) therein for receiving fasteners (not specifically shown) there through, thereby permitting height adjustable mounting of the removable and replaceable sealing flaps  147 . 
     The pick-up head system  100  further comprises a knife blade  70   k  mounted on an extension portion  70   e  of each of the door portions  146   a  through  146   i  (only one shown), namely the first door portion  146   a , and the second door portion  146   b , and so on. Each extension portion  70   e  projects substantially transversely from the door portions  146   a  through  146   i  substantially in the direction of rotation of the rotatable door assembly  146 . The knife blades knife blade  70   k  are for cutting debris entering the housing  110  through the sealed door assembly  150 . In use, as the surface cleaning vehicle  102  moves along the surface to be cleaned  104 , the knife blades  70   k , shred the received debris and thereby produces shredded debris. 
     In an alternative embodiment, it is contemplated that the sealed pick-up head system further comprises a knife blade mounted on the end edge of each door portion, instead of on the extension portion, for cutting debris entering the housing. 
     The sealed pick-head system  100  further comprises a selectively operable actuation means for causing the rotatable door assembly  146  to rotate. Preferably the selectively operable actuation means comprises a hydraulic motor  190 . The speed of the hydraulic motor  190  can be controlled by the operator of the surface cleaning vehicle  102 . Preferably, the rotatable door assembly  146  is rotated by the selectively operable actuation means  190  to have an outer circumferential speed substantially equal to the forward speed of the sealed pick-up head system  110  along a surface to be cleaned  104 , in a front-to-back direction. In this manner, the wearing of the rubber sealing flaps  147  on the surface to be cleaned  104  is minimized. 
     In order to control the rotational speed of the rotatable door assembly  146 , in the first preferred embodiment, as illustrated, a signal indicative of the speed of the vehicle and that is fed to the speedometer of the surface cleaning vehicle  102  is used by a control system (not specifically shown) that uses the signal to determine the speed of the mobile surface cleaning vehicle  102  traveling forwardly along the surface to be cleaned  104 . The control system would govern the speed of the selectively operable actuation means, namely the hydraulic motor  190 , accordingly. As a result, the relative speed of the rubber sealing flaps  147  with respect to the surface to be cleaned  104 , as the mobile surface cleaning vehicle  102  travels forwardly along the surface to be cleaned, would be zero, or very close to zero, depending on the accuracy of the control system and the selectively operable actuation means  190 . 
     In use, the rotatable door assembly  146  rotates forwardly at the top and rearwardly at the bottom, as indicated by arrows “A”, such that the rearward speed of the rubber sealing flaps  147  and the doors  146   a  through  146   i  with respect to the housing is the same as the speed of the mobile surface cleaning vehicle  102  traveling forwardly along the surface to be cleaned  104 . 
     Alternatively, the operator of the mobile surface cleaning vehicle  102  could set the rotational speed of the selectively operable actuation means  190  to rotate at any other desired speed. Rotating the selectively operable actuation means  190  more quickly such that the rubber sealing flaps  147  travel rearwardly with respect to the surface to be cleaned  104 , as the mobile surface cleaning vehicle  102  travels forwardly along the surface to be cleaned  104 , would help debris be pushed into the debris outlet  120 . The control system could be used to keep the speed of the rubber sealing flaps  147  constant with respect to the surface to be cleaned  104 . 
     In a first alternative embodiment, as shown in  FIG. 1N , the rotatable door assembly  146   A  further comprises at least one surface engaging member  149   A , and as illustrated comprises a first surface engaging wheel  149   a   A  disposed at the first side  146   a   A  of the rotatable door assembly  146   A  and a second surface engaging wheel  149   b   A  disposed at the second side  146   b   A  of the rotatable door assembly  146   A . The first surface engaging wheel  149   a   A  and a second surface engaging wheel  149   b   A  are preferably readily removable and replaceable by means of threaded fasteners (not specifically shown). Such rolling engagement causes the rotatable door assembly  146   A  to rotate such that the outer periphery  146   p   A  of the rotatable door assembly  146   A  has substantially a zero speed with respect to the surface being cleaned  104   A . 
     In use, the first surface engaging wheel  149   a   A  and a second surface engaging wheel  149   b   A  roll along the surface to be cleaned  104   A  and thereby carry the rotatable door assembly  146   A  along such that the rearward peripheral speed of the rotatable door assembly  146   A  matches the forward speed of the surface cleaning vehicle. Accordingly, the speed of the rubber sealing flaps  147   A  along the surface being cleaned is zero. 
     As can be readily seen in the figures, the rotatable door assembly  146 , the door frame  145 , the sealing flaps  147 , and the selectively operable actuation means  190  are connected in vertically movable relation to the housing  110  for movement between a lowered surface engaging position and a raised debris passing position. The rotatable door assembly  146 , the door frame  145 , the sealing flaps  147 , and the selectively operable actuation means  190  form a raisable and lowerable sealed door assembly, as indicated by the general reference  150 , that is mounted in hinged relation on the housing  110  by a suitable sealed hinge  143 . Alternatively, any other suitable means could be used, such as a pair of left and right opposed pins engaged in co-operating ball bearing mechanisms. A pliable material, possibly in bellows form, could be used to maintain a seal between the door frame  145  and the housing  110 , as necessary. 
     The sealed door assembly  150  is disposed immediately forwardly of the delivery duct  121 . The sealed door assembly  150  is moved between its lowered position and its raised position by means of a hydraulic cylinder  144   hc . The hydraulic cylinder  144   hc  is operatively interconnected between a mounting bracket  144   b  at the top of the sealed door assembly  150  and a mounting bracket  121   b  extending outwardly from the delivery duct  121 . 
     The hydraulic drive motor  190  is mounted on the top of the rotatable door assembly  150  via a chain drive  144   c . The chain drive  144   c  is covered by a small generally vertically oriented housing  144   h  in order to generally preclude dust and other contaminants from reaching the chain drive  144   c , and also to preclude the escape of air and dust from the housing  110 . 
     A rubber gasket type of material, or the like, is disposed at one or both of the sealed door assembly  150  and the opening of the debris receiving main inlet  142  of the housing  110 , in order to provide a seal between the sealed door assembly  150  and the housing  110  when the sealed door assembly  150  is in its lowered surface engaging position. 
     Alternatively, the sealed door assembly  150  could be mounted in vertically sliding relation on the housing  110  by means of a plurality of parallel rails that are oriented either generally vertically, or even at an angle to vertically. 
     In the lowered surface engaging position, the rotatable door assembly  146  would engage the surface to be cleaned as described above. In the raised debris passing position, the rotatable door assembly  146  would be disposed in spaced relation from the surface to be cleaned, thereby allowing large debris to readily enter the housing  110 , such as debris that might be too large to fit through the door frame  145  with the rotatable door assembly  146  in normal operation, or excessive amounts of large debris that need to be permitted into the housing quickly. In order to minimize the amount of time that the housing  110  might not be in a reduced air pressure situation, air cylinders could be used to quickly move the rotatable door assembly  146 , the door frame  145 , the sealing flaps  147 , and the selectively operable actuation means  190  between the lowered surface engaging position and the raised debris passing position. 
     There is also a first debris suctioning inlet  140   a  in the housing  110  disposed adjacent the first end  111  of the housing  110 , preferably at the first end  111  of the housing  110 , for suctioning dust and debris into the housing  110 . There is also a second debris suctioning inlet  140   b  in the housing  110  disposed adjacent the second end  112  of the housing  110 , preferably at the second end  112  of the housing  110 , for suctioning dust and debris into the housing  110 . Both the first debris suctioning inlet  140   a  and the second debris suctioning inlet  140   b  are disposed on opposite sides of the fore-aft central longitudinal axis “L” one from the other, and face laterally away from the fore-aft central longitudinal axis “L”. Further, the first debris suctioning inlet  140   a  and the second debris suctioning inlet  140   b  are disposed at a maximum distance “M” (see  FIG. 1K ) along the housing  110  from the debris outlet  120 , which is disposed generally centrally in the housing  110 , in a lateral sense. The various inventive aspects of the present invention, specifically the first preferred embodiment of the present invention, will now be discussed mostly with reference to the first debris suctioning inlet  140   a , in order to avoid unnecessary duplication. The same discussion also generally applies to the second debris suctioning inlet  140   b.    
     Furthermore, the first debris suctioning inlet  140   a  defines an external debris suctioning space  131  immediately beyond the first debris suctioning inlet  140   a  on the surface to be cleaned  104 , whereat debris disposed externally to the housing  110  and adjacent to the first debris suctioning inlet  140   a  can readily be suctioned into the housing  110 , and wherein the external debris suctioning space  131  is substantially unobstructed. 
     As can be seen in the figures, the first debris suctioning inlet  140   a  is preferably oriented forwardly, and more preferably oriented outwardly and forwardly, to permit the first debris suctioning inlet  140   a  to receive debris as the pick-up head system  100  travels along a surface to be cleaned  104 . 
     As can be seen in the figures, the back wall portion  116  extends outwardly away from the fore-aft axis “L” further than the front wall  115 , thereby creating a laterally and forwardly facing first debris suctioning inlet  140   a.    
     There is also a substantially unobstructed debris passage  130  within the housing  110  extending from the first debris suctioning inlet  140   a  to the debris outlet  120 . The debris outlet  120  is for receiving dust and debris from the debris passage  130  and permitting dust and debris to egress from the housing  110  into the hopper. The debris passage  130  is disposed within the housing in debris delivery relation with respect to the debris outlet  120 . 
     Preferably, the cross-sectional area from front-to-back and top-to-bottom of the debris passage  130  in the housing  110  from the first debris suctioning inlet  140   a  to the debris outlet  120  is substantially constant. Moreover, the height of the debris passage  130  is constant and the width the debris passage  130  is constant. 
     Debris is suctioned into the substantially hollow interior  119  of the housing  110 , and along the substantially unobstructed debris passage  130  through the first debris suctioning inlet  140   a . Furthermore, very small debris, such as dust, is suctioned into the substantially unobstructed debris passage  130  through the suctioning bottom opening  114  of the housing  110 . 
     In the first preferred embodiment as illustrated, the pick-up head system  100  further comprises a debris receiving main inlet  142  in the front wall  115  of the housing  110 , generally centrally disposed left-to-right in the housing  110 . Any debris that is pushed along the front wall  115  of the housing  110  from the first end (the right end) will reach the debris receiving main inlet  142 . A sealed door apparatus, as indicated by the general reference numeral  150 , is operatively mounted at the debris receiving main inlet  142  in the front wall  115  of the housing  110 . The sealed door apparatus  150  permits the passage of debris there through, while precluding air and dust from escaping from the housing  110 . The sealed door apparatus  150  allows the ingress of debris without sacrificing a properly reduced air pressure within the housing  110 . 
     The debris outlet  120  in the housing  110  permits dust and debris, including the shredded debris to be suctioned from the substantially hollow interior  119  of the housing  110  into the hopper. It will also be noted that the debris outlet  120  is generally centrally disposed in the back of the housing  110 , so as to be generally laterally aligned with the debris receiving main inlet  142 , and therefore with the sealed door apparatus  150 , so as to directly receive debris therefrom. 
     In the above described manner, since debris is shredded as it enters into the substantially hollow interior  119  of the housing  110 , the housing  110  can be lower in height. Accordingly, the housing  110  can have a smaller cross-section than prior art housings, and the debris outlet  120  and the delivery duct  121  can have a smaller cross-section, thus helping to maximize the efficiency and effectiveness of the first preferred embodiment debris shredding pick-up head system  100 . 
     A main fan  40  having an air inlet  40   i  and an air outlet  40   o  is mountable on a surface cleaning vehicle  102 , such as a street sweeping vehicle. The air inlet  40   i  is connected in air flow receiving relation to the hopper. The air outlet  40   o  is connected in air flow delivery relation to the debris passage  130 , for providing a flow of air for ingress into the debris passage  130 . 
     There is also an air supply passage  180  within the housing  110 . The air supply passage  180  has an air inlet  181  adjacent the debris outlet  120  and a first air outlet  182   a  adjacent the first end  111  of the housing  110  and a second air outlet  182   b  adjacent the second end  112  of the housing  110 . The housing  110  is substantially “V”-shaped and the debris outlet  120  is disposed adjacent the vertex of the “V”-shaped housing  110 . The first air outlet  182   a  is defined by a first curved wall portion  183   a  that directs the flow of air and debris from air supply passage  180  to the debris passage  130  in the proper direction to flow to the debris outlet  120 . Similarly, the second air outlet  182   b  is defined by a second curved wall portion  183   b  that directs the flow of air and debris from air supply passage  180  to the debris passage  130  in the proper direction to flow to the debris outlet  120 . 
     It is important that the first air outlet  182   a  of the air supply passage  180  is disposed in spaced relation from the debris outlet  120  so that the air emanating from the first air outlet  182   a  does not merely get suctioned into the debris outlet  120  without being effective in carrying dust and debris along the debris passage  130 . 
     The air inlet  181  is connectable to a source of high speed air flow, such as the main fan  40  of the surface cleaning vehicle  102 . The main fan  40  has an inlet  40   i  connected in air flow receiving relation to the debris hopper (not specifically shown), and an outlet  40   o  connected in air delivery relation to the air inlet  181  of the air supply passage  180 . The air supply passage  180  provides a flow of high speed air to the debris passage  130  at the first end  111  of the housing  110  and at the second end  112  of the housing  110  for cleaning the surface to be cleaned  104  substantially evenly from the first end  111  of the housing  110  to the debris outlet  120  and from second end  112  of the housing  110  to the debris outlet  120 . 
     In the first preferred embodiment as illustrated, the air supply passage  180  is disposed at the back of the housing  110 , with the air supply passage  180  being defined by the housing  110 , and a dividing portion  110   d  of the housing  110  separating the air supply passage  180  and the debris passage  130 . The air supply passage  180  is open along its length at the bottom of the housing  110  to permit the flow of high speed air to impact the surface to be cleaned  104  substantially along the entire length of the air supply passage  180 . This provides a final cleaning of the surface to be cleaned  104 . 
     The pick-up head system  100  further comprises as part of the substantially rigid debris deflecting skirt  108 , an interior skirt portion  108   i , disposed at the bottom edge of the dividing portion  110   d  of the housing  110  for interfacing the dividing portion  110   d  of the housing  110  in substantially sealed relation with the surface to be cleaned  104  as the surface cleaning vehicle  102  moves along the surface to be cleaned  104 . In some instances, it may be desirable for the interior skirt portion  108   i  to be raised slightly above the surface to be cleaned  104  in order to permit a very small amount of air flow thereunder, to enter the debris passage  130 . The interior skirt portion  108   i  preferably comprises a polyethylene type of material, such as ultra-high molecular weight polyethylene, or any other suitable type of material. 
     In use, the pick-up head system  100  is carried forwardly along the surface to be cleaned  104  by the surface cleaning vehicle  102  such that the substantially rigid debris deflecting skirt  108  disposed at the bottom of the peripheral edge  109  of the housing  110  and at the bottom edge of the dividing portion  110   d  of the housing  110  generally remain in substantially sealed relation with the surface to be cleaned  104 . The substantially rigid debris deflecting skirt  108  pushes small debris along itself laterally towards the sealed door apparatus  150  where the debris is taken into the housing  110  through the debris receiving main inlet  142 . A substantial and forceful stream of air is suctioned into the substantially hollow interior  119  of the housing  110 , specifically the debris passage  130 , through the first debris suctioning inlet  140   a  at the first end  111  of the housing  110 , where it enters the rightmost end of the debris passage  130  and travels to the debris outlet  120 . 
     Another forceful but typically lower volume stream of air is blown into the air inlet  181  of the air supply passage  180  whereat the flow of air impacts along the surface to be cleaned  104  thereby removing any remaining dust and other fine particulates from the surface to be cleaned  104 . 
     Most of the flow of air exits from the air supply passage  180  at its first air outlet  182   a  and re-enters the housing  110  at the first debris suctioning inlet  140   a  to join the ambient air that is being suctioned into the first debris suctioning inlet  140   a . In this manner, only the amount of ambient air that newly enters the housing  110 , which can be adjusted to be a small volumetric amount per unit time, needs to be filtered by the air filtration system of the service cleaning vehicle  102 . 
     Furthermore, a small portion of the air flow in the air supply passage  180  exits the air supply passage  180  forwardly under the interior skirt portion  108   i  on the bottom edge of the dividing portion  110   d  of the housing  110 . If the dividing portion  110   d  of the housing  110  is in its low position very close to the surface to be cleaned  104 , the cross-sectional area that the air flows through is correspondingly small, thereby causing the air to forcefully escape under the dividing portion  110   d  of the housing  110 . Accordingly, the air forcefully impinges on the surface to be cleaned  104 , thereby removing virtually all remaining dust and fine particulate matter. If the dividing portion  110   d  is raised slightly higher above the surface to be cleaned  104 , the air will less forcefully impinge on the surface to be cleaned  104 . 
     In another aspect, the present invention comprises a self-propelled surface cleaning system comprising the main vehicle  102  having a width “W V ”. The pick-up head  105  is operatively mounted on the main vehicle  102 . The pick-up head  105  includes the housing  110  extending between the first end  111  and a second end  112  to define a width “W H ” and extending substantially transversely to the fore-aft axis of travel “L”. The width “W H ” of the housing  110  of the pick-up head  105  is substantially the same as the width “W V ” of the main vehicle  102 . 
     The housing  110  includes the substantially hollow interior  119  and the suctioning bottom opening  114  defined by the bottom peripheral edge  109  and is open in fluid communication and debris transfer relation to the substantially hollow interior  119 . The first debris suctioning inlet  140   a  and the second debris suctioning inlet  140   b  are in the housing  110 , disposed adjacent the first end  111  and the second end  112 , respectively, of the housing  110 , for suctioning debris  101  into the housing  110 . The debris outlet  120  in the housing  110  is open in fluid communication and debris transfer relation to the substantially hollow interior  119  of the housing  110 . Debris  101  is suctioned into the substantially hollow interior  119  of the housing  110  through the debris suctioning inlets  140   a ,  140   b , and is discharged from the housing  110  through the debris outlet  120 . 
     Reference will now be made to  FIG. 2A , which shows a second preferred embodiment of the pick-up head system according to the present invention, as indicated by reference numeral  200 . The second preferred embodiment pick-up head system  200  is similar to the first preferred embodiment pick-up head system  100 , except that the housing  210  has a closed first end  211  a closed second end  212 . 
     Reference will now be made to  FIG. 3A , which shows a third preferred embodiment of the pick-up head system according to the present invention, as indicated by reference numeral  300 . The third preferred embodiment pick-up head system  300  is similar to the first preferred embodiment pick-up head system  100 , except that in the third preferred embodiment pick-up head system  300  there is an air flow apparatus  339  comprising a first air delivery duct  381  and a second air delivery duct  382 , each fed by a larger diameter single air delivery duct  380 , which receives a forceful flow of air from the main fan  340 . The first air delivery duct  381  and the second air delivery duct  382  are each secured to the rear wall  315  of the housing  310  by any suitable means. The first air delivery duct  381  curves forwardly at its outer end around the first end  311  of the housing  310 , and terminates just outside the first debris suctioning inlet  340   a  such that the first air outlet  382   a  is oriented generally downwardly and forwardly to thereby direct a blast of air at the first debris suctioning inlet  340   a  and at the surface to be cleaned  304 , and into the first debris suctioning inlet  340   a . Similarly, the second air delivery duct  382  curves forwardly at its outer end around the second end  312  of the housing  310 , and terminates just outside the second debris suctioning inlet  340   b  such that the second air outlet  382   b  is oriented generally downwardly and forwardly to thereby direct a blast of air at the second debris suctioning inlet  340   b  and at the surface to be cleaned  304 , and into the second debris suctioning inlet  340   b.    
     Reference will now be made to  FIG. 4A , which shows a fourth preferred embodiment of the pick-up head system according to the present invention, as indicated by reference numeral  400 . The fourth preferred embodiment pick-up head system  400  is similar to the first preferred embodiment pick-up head system  100 , except that the housing is substantially straight and is slanted rearwardly from the first debris suctioning inlet  440  to a left end wall portion  417  disposed at the second end  412  of the housing  410 . There is only one debris suctioning inlet  440  disposed at the first end  411  of the housing  410 . Further, the debris outlet  420  is disposed towards the second end  412  of the housing  410 . The debris receiving main inlet  442  and the sealed door apparatus  450  are also disposed adjacent the second end  412  of the housing  410 . The debris outlet  420  is disposed adjacent the back wall portion  416  of the housing  410  adjacent the second end  412  of the housing  410 . 
     Reference will now be made to  FIG. 5A , which shows a fifth preferred embodiment of the pick-up head system according to the present invention, as indicated by reference numeral  500 . The fifth preferred embodiment pick-up head system  500  is similar to the first preferred embodiment pick-up head system  100 , except that in the fifth preferred embodiment pick-up head system  500  there is no return of air from the main fan into the housing. Instead, the fifth preferred embodiment pick-up head system  500  is part of a vacuum type system. It can be seen that the debris passage  530  is wide open (no air supply passage) and there is no external air supply conduit. 
     Reference will now be made to  FIG. 6A , which shows a sixth preferred embodiment of the pick-up head system according to the present invention, as indicated by reference numeral  600 . The sixth preferred embodiment pick-up head system  600  is similar to the first preferred embodiment pick-up head system  100 , except that in the sixth preferred embodiment pick-up head system  600  the housing  610  extends between a first end  611  and a second end  612 , and extends substantially transversely to the fore-aft axis “L” of the housing  610 , and the rotatable door assembly  650  extends substantially the entire distance between the first end  611  and the second end  612  of the housing  610 . 
     Reference will now be made to  FIG. 7A , which shows a seventh preferred embodiment of the pick-up head system according to the present invention, as indicated by reference numeral  700 . The seventh preferred embodiment pick-up head system  700  is similar to the first preferred embodiment pick-up head system  100 , except that in the seventh preferred embodiment pick-up head system  700  the substantially sealed door apparatus  750  comprises a first rotatable support mechanism  752   a  rotatable about a first door axis “D 1 ”, a second rotatable support mechanism  752   b  rotatable about a second door axis “D 2 ”, and a third rotatable support mechanism  752   c  rotatable about a third door axis “D 3 ”. A flexible ring-shaped belt  754  is mounted peripherally around the first rotatable support mechanism  752   a , the second rotatable support mechanism  752   b , and the third rotatable support mechanism  752   c , for peripheral movement of the flexible ring-shaped belt  754  peripherally about the first rotatable support mechanism  752   a , the second rotatable support mechanism  752   b , and the third rotatable support mechanism  752   c , in a direction as indicated by arrow “A”. 
     A drive mechanism  756  operatively engages the flexible ring-shaped belt  754  in driving relation, via the first rotatable support mechanism  752   a , to thereby drive the flexible ring-shaped belt  754  through its peripheral movement. The flexible ring-shaped belt  754  is substantially solid to thereby preclude the flow of air therethrough. A plurality of doors  758  are mounted in outwardly extending relation on the flexible ring-shaped belt  754  such that each door can contact a surface being cleaned  704 . An air flow barrier  759  is operatively disposed between the plurality of doors  758  and the housing  710  to substantially preclude the passage of air and small debris between the plurality of doors  758  and the housing  710 . 
     As can be understood from the above description and from the accompanying drawings, the present invention provides a full-width dustless pick-up head system, full-width dustless pick-up head system wherein the effective size of the debris receiving opening whereat the substantially sealed door apparatus is mounted, can be more than about half the width of the pick-up head, and wherein the effective size of the debris receiving opening whereat the substantially sealed door apparatus is mounted, can be the full width of the pick-up head, all of which features are unknown in the prior art. 
     Other variations of the above principles will be apparent to those who are knowledgeable in the field of the invention, and such variations are considered to be within the scope of the present invention. Further, other modifications and alterations may be used in the design and manufacture of the pick-up head system of the present invention without departing from the spirit and scope of the accompanying claims.