Abstract:
A vacuum broom apparatus for removing particulate debris from surfaces such as those of floors includes a housing which has an upper wall from which protrudes a vacuum inlet tube connectable to a vacuum power source. The housing includes a shroud which protrudes downwardly from the upper wall and peripherally surrounds a broom which protrudes downwardly within the shroud through a bottom opening thereof. One or more vacuum nozzles which communicate with the vacuum inlet tube are positioned adjacent to the broom. Optionally, a front wall of the shroud is elastically flexible to thereby effect an air dam between a lower edge of the front wall and a floor surface against which it may be pressed. Also, the broom may take the form of a block which at least partly encloses a lower entrance opening of the shroud, the block having a lower surface from which bristles protrude downwardly, and a plurality of vacuum passageways interspersed within the bristles and which have lower debris entrance openings in the lower surface of the block, and upper debris exit openings through an upper surface of the block which communicates with a negative pressure region of an interior region of the shroud.

Description:
This is a Continuation-In-Part application of Ser. No. 10/315,956, filed on Dec. 10, 2002, now abandoned. 

   BACKGROUND OF THE INVENTION 
   A. Field of the Invention 
   The present invention relates to devices and apparatus for removing dust and dirt from floors. More particularly, the invention relates to a vacuum broom apparatus which utilizes a synergistic combination of sweeping and vacuuming functions to efficiently remove dirt and dust from floor surfaces while minimizing undesired dispersal of errant dust or dirt particles into the atmosphere. 
   B. Description of Background Art 
   Periodic removal of dust, dirt and other debris which accumulates on floors of buildings is performed using a limited variety of well known methods. Thus concrete floors of small industrial or commercial buildings are sometimes washed or hosed down but more typically swept with hand-operated push brooms. Floors of larger buildings are sometimes cleaned using motor-driven rotating brushes which are mounted on a wheeled sweeper apparatus that is pushed by hand, or on a self-propelled sweeper. Dust and dirt accumulated on carpeted surfaces in commercial buildings and residences is typically removed using a vacuum cleaner, which oftentimes includes a wheeled head attachment that includes a rotating brush and a beater bar to agitate carpet fibers and thereby facilitate releasing dirt into a plenum within the head which is subjected to negative pressure produced by a motor-driven blower fan located external to the head. 
   Vacuum cleaner heads that include motor-driven roller brushes or beater bars and intended for use on carpeted surfaces are generally not well suited for use on hard floor surfaces such as those of tile, concrete, stone or the like. Accordingly, vacuum cleaner kits are typically provided with nozzles of various sizes and shapes which are interchangeably connectable to the lower or outer end of a hollow tubular handle, the upper end of which is coupled through a vacuum hose to a source of negative pressures. Some nozzles which are intended for use on non-carpeted floor surfaces are provided with brush bristles that extend downwardly from a lower surface of the nozzle body, the bristles being arranged in a ring which peripherally encloses a centrally located suction input opening of the nozzle. The brush bristles function as a flexible air dam which makes 
   a partial hermetic seal between the suction input opening of the nozzle and the hard surface of a floor on which the nozzle is drawn across. The bristles also help to dislodge debris particles adhered to a floor surface. However, this dislodging action is problematic because it is confined to a region which peripherally encircles the suction inlet opening of the nozzle, and thus tends to not only inefficiently gather dislodged debris particles, but undesirably scatters a good percentage of the particles into the atmosphere. The present invention was conceived of to provide a vacuum broom apparatus for effectively cleaning floor surfaces while causing a minimal amount of dispersal of dust and dirt into the atmosphere. 
   OBJECTS OF THE INVENTION 
   An object of the present invention is to provide a portable vacuum broom apparatus for removing dirt, dust, and other particulate debris from surfaces, primarily of floors. 
   Another object of the invention is to provide a vacuum broom apparatus which includes a vacuum power unit that is coupled to a cleaner head which includes vacuum inlet passageways that are peripherally arranged with respect to broom or brush bristles. 
   Another object of the invention is to provide a vacuum broom apparatus which includes a cleaner head that includes a housing or cover shell which has an elastically flexible front wall. 
   Another object of the invention is to provide a vacuum broom apparatus which includes a cleaner head that has a bulkhead, a broom which protrudes downwardly from the bulkhead, a shroud which peripherally surrounds the bulkhead and broom, and a vacuum passageway located between the broom and a shroud wall, the vacuum passageway having a debris inlet port adjacent to the broom and a debris outlet port connectable to a vacuum source. 
   Another object of the invention is to provide a vacuum broom apparatus which includes a cleaner head that has a box-like housing which has an open bottom and which includes an elastically flexible front wall, a generally upwardly disposed rear wall, and generally upwardly oriented side walls which are disposed transversely to the front and rear walls, the housing having located therein a vacuum passageway provided with a debris inlet port, and a vacuum source inlet port exterior to the housing. 
   Another object of the invention is to provide a vacuum broom which includes a height-adjustable broom located with the hollow interior space of hollow vacuum box. 
   Another object of the invention is to provide a vacuum broom which includes a hollow vacuum box, a broom holder, and a plurality of vacuum passageways provided with debris inlet ports located adjacent to the broom, at least one of which passageways being provided with an air flow control valve. 
   Another object of the invention is to provide a vacuum broom apparatus which includes a cleaner head that has a generally box-like shape including a hollow interior space which is connected by a hollow swivelable handle to a vacuum source, and a bottom perforated sweeper block which includes a matrix of perforations disposed upwardly from a lower surface of the block to a vacuum plenum space within the head, and a matrix of brush bristles which are interspersed with the perforations and which depend downwardly from the lower surface of the block. 
   Various other objects and advantages of the present invention, and its most novel features, will become apparent to those skilled in the art by perusing the accompanying specification, drawings and claims. 
   It is to be understood that although the invention disclosed herein is fully capable of achieving the objects and providing the advantages described, the characteristics of the invention described herein are merely illustrative of the preferred embodiments. Accordingly, I do not intend that the scope of my exclusive rights and privileges in the invention be limited to details of the embodiments described. I do intend that equivalents, adaptations and modifications of the invention reasonably inferable from the description contained herein be included within the scope of the invention as defined by the appended claims. 
   SUMMARY OF THE INVENTION 
   Briefly stated, the present invention comprehends a portable vacuum broom apparatus for removing particulate debris including dirt and dust from the surfaces of floors of buildings and other such structures. A basic embodiment of a vacuum apparatus according to the present invention includes a cleaner head which comprises a hollow box-like enclosure that has an open bottom and includes a generally flat rear panel jointed at outer upright side edges thereof to a pair of flat side panels, the side panels being joined at the front edges thereof to a front panel which preferably has a lower forwardly angled curved portion that has a lower transversely disposed horizontal edge. Preferably, at least the lower curved portion of the enclosure is made of an elastically flexible material, thus forming a flexible apron which is capable of forming a relatively air-tight seal with a floor surface against which the apron is pressed down against as the head is pushed or pulled parallel to a surface being cleaned. 
   Cleaner heads according to the present invention preferably include at least one suction nozzle located within the hollow interior space of the head enclosure, the nozzle having a lower debris entrance opening and a vacuum passageway terminating at the upper end thereof in a vacuum inlet port. In preferred embodiments of cleaner heads according to the present invention, a block-shaped, transversely disposed bulkhead is located within an upper part of the head enclosure, adjacent to the upper inner wall surface of the head enclosure, and joined to the inner surfaces of opposite side walls of the head enclosure. 
   A basic embodiment of a cleaner head according to the present invention includes a rear suction nozzle which has a generally upright rear wall formed by the inner wall surface of the rear enclosure panel, a front wall formed by a rear surface of the bulkhead, and a generally conically tapered tubular transition section which protrudes upwardly from the upper surface of the enclosure, and terminates in a cylindrically-shaped vacuum inlet tube. A basic embodiment of cleaner head rear nozzle according to the present invention also includes a web which depends downwardly from a rear surface of the bulkhead. The web forms a skirt which spans the width of the hollow interior space of the enclosure, the skirt having a lower transversely disposed edge wall spaced forward of the lower edge wall of the rear enclosure panel and forming therewith and with inner surfaces of opposite side panels of the head enclosure a transversely disposed, generally rectangular-shaped, upwardly disposed debris entrance opening of the rear nozzle. 
   Basic embodiments of vacuum broom cleaner heads according to the present invention also include a broom which has a neck that is secured within the bulkhead, and downwardly protruding bristles. The body of the broom preferably is symmetrically positioned with respect to the inner wall surfaces of the enclosure panel walls, with the bottom ends of the bristles located at a height approximating that of the bottom edge wall of the front enclosure apron. Optionally, cleaner heads according to the present invention include a telescopically or pivotably adjustable broom neck holder to enable adjusting the height of the broom bristles relative to the apron&#39;s lower edge wall. Preferred embodiments of the cleaner heads also include a release mechanism which enables replacement of worn brooms, or their removal for certain applications. 
   Alternate embodiments of vacuum broom cleaner heads according to the present invention include a front vacuum nozzle located between a rear inner wall surface of the front enclosure panel and a front surface of the bulkhead, and may also include a rear nozzle located rearward of the broom as described above. Other embodiments of vacuum broom cleaner heads according to the present invention include a valve plate which may be slid into a vacuum nozzle passageway to restrict the flow of air streams containing debris to open nozzle passageways, and a broom height adjustment lever optionally combined with a valve actuator lever. 
   Another embodiment of a vacuum broom cleaner head according to the present invention has a perforated brush block which encloses a portion of a lower entrance opening of the head enclosure, the brush block having a matrix of brush bristles or bundles which protrude downwardly from a lower surface of the block, and which are interspersed with a matrix of perforations that have debris entrance openings in the lower surface of the block, and vacuum inlet openings in the upper surface of the block. The latter communicate with a hollow interior space or plenum of the enclosure, which is connected by a hollow swivelable handle to a vacuum source. Optionally, a front, laterally disposed edge of the brush block is located rearward of the front enclosure panel, the upper front edge forming between an inner surface of the upper panel and side panels of the enclosure a laterally elongated, rectangularly-shaped opening which communicates with the hollow interior space of the enclosure and thus comprises a front vacuum nozzle, which is optionally closable by means of a lever operated, transversely disposed valve plate attached to the upper enclosure panel in a fore-and-aft slidable fashion. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a vacuum broom apparatus according to the present invention. 
       FIG. 2  is a perspective view of a vacuum power unit component of the apparatus of  FIG. 1 , on an enlarged scale. 
       FIG. 3  is a vertical longitudinal sectional view of the vacuum power unit of  FIG. 2 , taken in the direction of line  3 - 3  in  FIG. 2 . 
       FIG. 4  is a fragmentary longitudinal sectional view of the apparatus of  FIG. 1 , showing a releasable coupler for removably coupling a cleaner head thereof to a handle thereof. 
       FIG. 5  is a fragmentary longitudinal sectional view of the apparatus of  FIG. 1 , showing a telescopically adjustable coupler for coupling the handle thereof to a hose thereof. 
       FIG. 6  is a transverse sectional view of a spring-loaded detent button mechanism of a type used in both the releasable coupler of  FIG. 4  and telescopically adjustable coupler of  FIG. 5 . 
       FIG. 7  is a front elevation view of a cleaner head comprising part of the apparatus of  FIG. 1 . 
       FIG. 8  is a rear elevation view of the cleaner head of  FIG. 7 . 
       FIG. 9  is a vertical longitudinal sectional view of the cleaner head of  FIGS. 7 and 8 , taken in the direction of line  9 - 9  in  FIG. 1  and showing a broom component of the head in a lowered, extended position relative to a housing component of the head. 
       FIG. 10  is a view similar to that of  FIG. 9 , but showing the broom in a raised, retracted position. 
       FIG. 11  is a vertical longitudinal sectional view of a first modification of a cleaner head for the apparatus of  FIG. 1 , in which a rearwardly located broom thereof is adjusted to an upward, retracted position relative to a housing thereof. 
       FIG. 12  is a view similar to that of  FIG. 11 , but showing the broom in an extended, lowered position. 
       FIG. 13  is a fragmentary longitudinal sectional view of the head of  FIG. 11  in the direction of line  13 - 13  in a plane perpendicular to that of  FIG. 11 , showing a broom height adjusting lever and attached valve plate thereof in an upper, retracted disposition to block air flow. 
       FIG. 14  is a vertical longitudinal sectional view of a second modification of a cleaner head for the apparatus of  FIG. 1 , in which a valve plate thereof is adjusted to a downwardly extended disposition which permits air flow through a passageway of the valve. 
       FIG. 15  is a view similar to that of  FIG. 14 , but showing the valve plate retracted upwardly to block air flow, and showing a broom holder mechanism thereof adjusted to a release position. 
       FIG. 16  is a fragmentary longitudinal sectional view of the head of  FIG. 14  taken in the direction of line  16 - 16  in a plane perpendicular to that of  FIG. 14 , showing a valve adjustment lever and attached valve plate thereof in a lower, extended position to permit air flow. 
       FIG. 17  is a fragmentary vertical longitudinal sectional view of the head of  FIG. 14 , showing a broom holder mechanism thereof on an enlarged scale. 
       FIG. 18  is a left side elevation view of the vacuum power unit of  FIGS. 2 and 3 . 
       FIG. 19  is an upper plan view of the vacuum power unit of  FIG. 18 . 
       FIG. 20  is a partly broken away rear elevation view of the vacuum power unit of  FIG. 18 . 
       FIG. 21  is a front elevation view of the vacuum power unit of  FIG. 18 . 
       FIG. 22  is a lower plan view of the vacuum power unit of  FIG. 18 . 
       FIG. 23  is a view similar to that of  FIG. 2 , but showing a lower cover plate of the vacuum power unit removed. 
       FIG. 24  is a perspective view of a modification of the vacuum power unit of  FIG. 18 , which is provided with casters. 
       FIG. 25  is an upper perspective view of a third modification of a cleaner head for the apparatus of  FIG. 1 . 
       FIG. 26  is a vertical medial longitudinal sectional view of the head of  FIG. 25 , taken in the direction of line  26 - 26  in  FIG. 25 . 
       FIG. 27  is a transverse vertical longitudinal sectional view of the head of  FIG. 27 , taken in the direction indicated by the line  27 - 27  in  FIG. 25 . 
       FIG. 28  is a fragmentary view of the head of  FIG. 25 , showing how a perforated brush block thereof is releasably latched within a bottom opening of a housing thereof. 
       FIG. 29  is a lower plan view of the head of  FIG. 25 . 
       FIG. 30  is an upper plan view of the head of  FIG. 25 . 
       FIG. 31  is an upper plan view of a first modification of the head of  FIG. 30 . 
       FIG. 32  is an upper plan view of a second modification of head of  FIG. 30 . 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIGS. 1-10  illustrate features of a basic embodiment of a vacuum broom apparatus according to the present invention. 
     FIGS. 11-13  illustrate a first modification of a cleaner head for use in the apparatus of  FIGS. 1-10 . 
     FIGS. 14-17  illustrate a second modification of a cleaner head. 
     FIGS. 18-23  illustrate details of a vacuum power unit comprising a component of the apparatus of  FIGS. 1-10 . 
     FIG. 24  illustrates a modification of the vacuum power unit of  FIGS. 18-23 . 
     FIGS. 25-30  illustrate features of a third modification of a cleaner head for use in the apparatus of  FIGS. 1-10 . 
     FIGS. 31 and 32  illustrate modifications of the cleaner head of  FIGS. 25-30 . 
     FIGS. 1-10  illustrate a basic embodiment  50  of a vacuum broom apparatus according to the present invention. As shown in  FIG. 1 , apparatus  50  includes a cleaner head  51  which includes a hollow body  52  that has protruding from an upper surface  53  thereof an upwardly and rearwardly angled vacuum inlet tube  54 . Vacuum inlet tube  54  is connected by a releasable coupler  55  to the lower end of an elongated hollow tubular handle  56 , the upper end of which is connected via a telescopically adjustable coupler  57  to a free end of a vacuum hose  58  which has a fixed end attached to a vacuum power unit  59 . As shown in  FIGS. 2 and 3  and as will be described in detail below, vacuum power unit  59  includes an electric motor  60  which rotates a fan  61  to produce a negative pressure or partial vacuum within the hollow interior space  62  of a housing  63  of the vacuum power unit, negative pressure being coupled through hose  58  and handle  56  to cleaner head  51 . 
   Referring to  FIGS. 18-23  in addition to  FIGS. 1-3 , it may be seen that vacuum power unit  59  is preferably mounted on a horizontally disposed base  65  of an L-shaped support structure  64  which has an upright member  66  to which are attached a pair of vertically disposed, laterally spaced apart left and right shoulder straps  67 ,  68  which facilitate transporting the vacuum power unit on a person&#39;s back as shown in  FIG. 1 . 
   As may be seen best by referring to  FIG. 3 , vacuum power unit  59  has a hollow, generally cylindrically-shaped base portion  69  surmounted by a hollow, generally frusto-conically-shaped upper end cap portion  70 . Preferably, a relatively longer upper portion  71  of cylindrical base portion  69  is fabricated unitarily with upper end cap portion  70 , and releasably attached to a relatively shorter lower base portion  72  by a plurality of circumferentially spaced apart toggle latches  73 . Short base portion  72  has a circularly-shaped upper bulkhead wall  74  which serves as a base plate for supporting a hollow cylindrically-shaped main dirt filter  75 , the upper end  76  of which is received an annular shoulder groove  76 A formed in a lower inner surface of upper end cap  70 . 
   As shown in  FIG. 3 , upper end cap  70  of vacuum power unit  69  has disposed longitudinally therethrough a tapered bore  77  which has an upper entrance opening  78  adapted to insertably receive an end of vacuum hose  58 , and lower circular exit bore  79  of larger, diameter which communicates with a blind cylindrical bore  80  of main dirt filter  75 . As indicated by the curved arrows in  FIG. 3 , negative pressure produced in a hollow cylindrical space or upper fan plenum  81  within that portion of base  72  located above fan  61 , by rotation of fan  61  draws dirt laden air through entrance bore  78  of vacuum power unit  59 , through bores  77 ,  79 , and  80 , through passageways  82  in porous main filter  75 , through a longitudinally elongated annular space  83  between inner wall surface  84  of housing  69  and outer surface  85  of the filter, through perforations  86  in filter support plate  74 , between blades  87  of the fan, into a lower cylindrically-shaped fan plenum  88 , and outward through an exhaust port  89  to the atmosphere. As shown in  FIG. 2 , exhaust port  89  is preferably fitted with a grate  90 , and optionally fitted with a hose fitting  91  to which may be attached an exhaust hose  92  for directing an air stream produced by the vacuum power unit to an external location. 
   As is shown in  FIGS. 2 ,  23  and  20 , vacuum power unit  59  may also contain a secondary filter  93  which has a flat annular ring shape adapted to fit into a cylindrically shaped lower vacuum outlet plenum  94  located below lower fan plenum  88 . As shown in  FIGS. 2 ,  22  and  23 , secondary filter  93  is retained in base portion  72  of vacuum power unit  59  between an upper retainer plate  95  provided with a perforated circular grate  96 , and a bottom cover plate  97  which is releasably retained in a bore  99  through bottom base plate  98  of base  72 , using a handle  100  which protrudes downwardly from the base plate. 
   A preferred embodiment of vacuum power unit  59  supplies electrical power from a battery pack (not shown) to fan motor  60  through a power switch  101  located on the on upright  66  of vacuum power unit support structure  64 . Also, vacuum power unit preferably includes a red low-battery charge indicator lamp  102 , a green full-charge indicator  103 , and a charger connection jack  104  for connecting an external power source to the vacuum power unit battery pack. 
     FIG. 24  illustrates a modification  59 A of vacuum power unit  59 , which is provided with a plurality, preferably 4, of wheeled casters  106  which are mounted at the corners on a lower surface  107  of support structure base  65 . 
   Referring again to FIGS.  1  and  4 - 6 , it may be seen that flexible vacuum hose  58  has attached to a free end thereof a rigid tubular coupler member  108  which has a longitudinally disposed coaxial bore  109  that communicates with bore  110  of the hose. Bore  109  of tubular member  108  is of the proper diameter to snugly and telescopically receive the upper end  111  of handle  56 , which has through a cylindrical wall surface  112  thereof a radially disposed bore  113  that communicates with a longitudinally disposed bore  114  of handle end. As shown in  FIG. 6 , upper handle end  111  includes a detent button  115  which is urged elastically outwardly within radial bore  113  by a spring  116 , which in  FIG. 6  is shown to have the shape of a flat leaf that is bent into a circular arc segment forced by spring hoop tension to lodge against circular wall surface  117  of bore  114 . Optionally, spring  111  can have the shape of straight cantilevered leaf spring which is disposed longitudinally within bore  114  and secured at an end opposite detent button to wall  112  of upper handle section  111 . 
   As shown in  FIG. 5 , rigid tubular coupler member  108  of hose  58  has disposed through cylindrical wall  118  thereof a plurality of, longitudinally spaced apart circular holes  119  which are adapted to releasably receive detent button  115 , thus enabling handle  56  to be attached to hose  58  with the lower end  55  of the handle adjusted to a desired extension length relative to hose  58 . 
   As shown in  FIG. 4 , vacuum inlet tube  54  of cleaner head  51  has a bore  120  of the proper diameter to snugly and telescopically receive the lower end  121  of handle  56  which has through a cylindrical wall surface  122  thereof a radially disposed bore  123  that communicates with longitudinally disposed bore  114  of the handle. Lower handle end  121  includes a lower detent button  125  and spring  126 , the structure and function of which are exactly analogous to those of upper detent button  115  and spring  120  described above. Thus, when lower tubular end  121  of handle  56  is inserted into bore  120  of cleaner head vacuum inlet tube  54 , spring  125  urges detent button radially outwardly to releasably engage a bore  129  disposed radially through cylindrical wall  128  of the vacuum inlet tube. 
   The structure and function of a basic embodiment  51  of a cleaner head for use in the apparatus  50  shown in  FIG. 1  may be best understood by referring to  FIGS. 7-10  in addition to  FIG. 1 . 
   As shown in  FIGS. 1 ,  7  and  8 , body  52  of cleaner head  51  includes a hollow box-like enclosure or housing  130  which has generally flat, parallel, vertically disposed left and right side wall panels  131 ,  132 . As shown in  FIG. 1 , left and right side wall panels  131 ,  132  each has a lower portion  133 ,  134 , respectively, which has a shape approximating that of a vertically elongated rectangle, modified by a convex, arcuately curved upper edge wall  135 ,  136 , respectively. Housing  130  also has a front wall panel  137  which is disposed transversely to left and right side wall panels  131 ,  132 . Front panel  137  has the shape approximating that of a sinuously curved vertically elongated rectangular plate which is relatively longer than left and right side wall panels  131 ,  132 . Front wall panel  137  has a lower concavely curved portion  138  which has transversely disposed edge wall  139  that protrudes below lower edge walls  140 ,  141 , respectively, of the left and right side wall panels. Front wall panel  137  also has a relatively straight intermediate portion  142 , and a convex, arcuately curved upper end portion  142 T which is disposed transversely to upper edge walls  135 ,  136  of left and right side panels  131 ,  132 , and which comprises a major portion of an upper cover panel of enclosure  130 . 
   As may be seen best by referring to  FIGS. 7 ,  8  and  9 , enclosure  130  of cleaner head  51  has a generally flat rear wall panel  143  which has a lower vertically elongated rectangular-shaped portion  144  that is disposed transversely to left and right side panels  131 , and has a lower edge wall  145  joined to lower edge walls  146 ,  147 , respectively, of the side wall panels. 
   In a preferred embodiment of cleaner head  51 , at least lower concavely curved portion  138  of front wall panel  137  is made of an elastically flexible material, such as and elastic or elastomeric polymer, e.g., polyethylene. 
   As shown in  FIGS. 9 and 10 , cleaner head  51  has a hollow interior space  148  formed between inner surfaces of the front, rear and side wall panels of enclosure  130 . Also, cleaner head  51  preferably has at least one vacuum nozzle, e.g., a rearwardly located vacuum nozzle  149 , which has a bore  150  that communicates with bore  120  of vacuum inlet tube  54 . As is also shown in  FIGS. 9 and 10 , rear vacuum nozzle  149  is formed by an elongated space  151  located between inner surfaces of rear wall panel  143 , left and right side wall panels  131 ,  132 , and the rear wall surface  152  of a block-shaped bulkhead  153  which is disposed transversely between the side wall panels and front wall panel  137 . In a preferred embodiment, bulkhead  153  has protruding downwardly from a lower transversely disposed surface  154  thereof a thin, generally rectangular shaped plate-like web which forms a skirt  155  that has a rear surface  152 A which is continuous with rear surface  152  of the bulkhead, and a front surface  155 A which is parallel to the rear surface of the skirt. Formed between a lower transverse edge wall  156  of rear wall panel  143  and a lower transverse edge wall  157  of skirt  155  is a generally rectangularly-shaped laterally elongated debris entrance opening  158  of nozzle  149 . Referring still to  FIGS. 9 and 10 , lower edge wall  157  of skirt  155  preferably is angled or most preferably arcuately curved forward towards open space  148  of cleaner head  51 . 
   Referring now to FIGS.  1  and  7 - 10 , it may be seen that cleaner head  51  of vacuum broom apparatus includes a brush or broom  160  which is formed of a vertically disposed laterally elongated bundle of bristles  161 , upper ends of which are compressed together to form a shorter, vertically elongated generally cylindrically-shaped neck  162 . Neck  162  is preferably mounted in bulkhead  153  by a releasable mount so that broom  160  can be readily replaced when worn out, or when it is desired to use cleaner head  51  without the presence of a broom. Thus, as shown in  FIGS. 9 and 10 , neck  162  of broom  160  is releasably fastened within a mounting bushing  163 , that is telescopically slidably mounted within a blind bore  164  disposed vertically through a central portion of bulkhead  153 , to enable the height of the lower sweeping surface  165  of broom  160  to be adjusted to a desired value relative to lower edge wall  139  of front wall panel  137 . As shown in  FIGS. 9 and 10 , a mechanism for adjusting the height of broom  160  includes a push rod  166  which protrudes upwardly from upper surface  167  of mounting bushing  163 , through a through-bore  168  in upper wall surface  142 T of housing  130 . Optionally, a helical compression spring  169  may be positioned coaxially over bushing  153  and between inner wall surface  170  of bore  169 , to retain broom  160  in an upwardly biased position. 
     FIGS. 11-13  illustrate a first modification  51 A of the cleaner head  51  shown in  FIG. 1  and described above. As shown in  FIG. 11 , modified cleaner head  51 A has a bulkhead  153 A disposed transversely between inner surface  172 A of right side wall  132 A and the inner surface of the left side wall (not shown) which has a more generally triangular or wedge-like vertical longitudinal cross-sectional shape than that of bulkhead  153  of cleaner head  51  shown in  FIGS. 9 and 10 . Thus, as shown in  FIG. 11 , bulkhead  153 A has a generally flat, transversely disposed horizontal bottom surface  173 , and a front rearwardly upwardly angled and curved wall surface  174 . Bulkhead  153 A also has a rear surface  175  which includes a transversely disposed generally vertical lower portion  176 , and a forwardly and upwardly angled portion  177 , which intersects front bulkhead wall surface  174  to form a generally triangular-shaped, transversely disposed vertex  178 . 
   Front surface  174  of bulkhead  153 A is spaced rearwardly of inner surface  179  of front panel wall  137 A, forming therebetween a front nozzle  180  which has a lower transversely disposed horizontal debris entrance opening  181  that is coplanar with bottom surface  173  of bulkhead  153 A. Front nozzle  180  also has a sinuously curved duct passageway  182  which communicates at a lower end thereof with debris opening  181  and at an upper end thereof with bore  120 A of vacuum inlet tube  54 A. 
   Referring still to  FIGS. 11 and 12 , it may be seen that modified cleaner head  51 A includes a rear nozzle  190  formed between inner surface  191  of rear wall panel  140 A, and rear surface  175  of bulkhead  153 A. Rear nozzle  190  has a lower transversely disposed debris entrance opening  191  which is coplanar with bottom surface  173  of bulkhead  153 A. Rear nozzle  190  also has a sinuously curved rear nozzle duct passageway  192  which communicates at a lower end thereof with debris entrance opening  191 A and at an upper end thereof with bore  120 A of vacuum inlet tube  54 A. 
   As shown in  FIGS. 11 and 12 , modified cleaner head  51 A includes a broom  160  which has a neck  162 A that is mounted in a bushing  163 A which is telescopically slidably held within a blind bore  164 A in the lower part of bulkhead  153 A. 
   Referring to  FIG. 13  in addition to  FIGS. 11 and 12 , it may be seen that bushing  163 A is telescopically movable within bore  164 A of bulkhead  153 A by means of a push rod  166 A which protrudes upwardly through a hole  168 A through upper wall surface  195  of housing  130 A. Lower end  196  has protruding laterally therefrom a vertically disposed wheel  197  which is rollable in fore-and-aft directions within a slotted track  198  disposed in a fore-and-aft direction on the upper surface  163 A of bushing  163 A. The push rod, wheel and track constitute a mechanism which enables longitudinal motion of push rod  166 A, which is angled with respect to the vertical axis of bushing  163 A, to effect vertical up and down motion of the bushing and attached broom  160 . As shown in  FIGS. 11-13 , push rod  166 A preferably has attached to an intermediate longitudinal part thereof a flat valve plate  199 , which obstructs rear nozzle duct  192  when the push rod is in an upwardly retracted position, and which unblocks the passageway when the push rod is in its downwardly depressed position. 
     FIGS. 14-17  illustrate a second modification  51 B of a cleaner head  51  according to the present invention. As shown in  FIGS. 14-16 , modified cleaner head  51 B includes a valve plate  209  which is mounted on the lower end of a push rod  216  that is disposed upwardly through a hole  168 B through upper surface  195 B of enclosure  130 B of the cleaner head. When push rod  216  is retracted fully upwards, valve plate  209  blocks air flow through rear vacuum nozzle passageway  192 B, and when the push rod is depressed fully downwards, the rear vacuum nozzle passageway is unobstructed. 
   As shown in  FIGS. 14-17 , modified cleaner had  51 B also includes a releasable broom holder mechanism  220  which facilitates removing and replacing a broom  160  from the head. As shown in  FIGS. 14-17 , releasable broom holder mechanism  220  includes a lever arm  221  which has a rear portion  222  that protrudes horizontally rearwardly through a hole  223  in rear wall panel  143 B of cleaner head enclosure  130 B. Lever arm  221  also has a front portion  224  which protrudes forwardly into a cavity  225  formed in rear surface  226  of bulkhead  153 B, where an inner end  227  of the lever arm is connected by an upper pivot pin  228  to the upper end of a downwardly disposed bell crank arm  229 . A lower end of bell crank arm  229  is pivotably fastened at a lower end thereof by a lower pivot pin  230  to a lug  231  which protrudes rearwardly from bulkhead  131 . Bell crank arm  229  has protruding perpendicularly from a short upper portion  232  thereof an inverted L-shaped arm  233 . The latter is provided at the lower end with a forward protruding tang  234 . Lower L-shaped arm  233  of bell crank arm  229  is urged to a vertical position by a torsion spring  235 , whereby tang  234  is urged forward into locking engagement within an annular groove  236  formed in the outer wall surface of broom holder bushing  163 B, near the lower end thereof. The forward directed force exerted on broom holder bushing  163 B also urges a front part of annular bushing groove  236  into locking engagement by a front wall tang  237  which protrudes rearwardly from a rear wall surface  238  of bulkhead  153 B. 
     FIGS. 25-32  illustrate a third embodiment of a vacuum broom cleaner head  51 C for use within vacuum broom apparatus  50  of  FIG. 10 . 
   As shown in  FIGS. 25-29 , vacuum cleaner head  51  includes a housing  240  which has the shape of a short, generally rectangularly-shaped box which includes a generally flat, rectangularly-shaped upper wall panel  241  that has protruding perpendicularly downwardly therefrom left and right flange walls  242 ,  243  which have a generally rectangular shape elongated in a fore-and-aft direction. Housing  240  also has a rear flange wall  244  which has a laterally elongated, generally rectangular shape and which protrudes generally perpendicularly downwards from a rear edge of upper wall panel  240 . Housing  240  also has a front generally rectangularly-shaped, laterally elongated wall panel  245  which angles forward obliquely from a front edge of upper wall panel  241 . 
   As shown in  FIG. 26 , housing  240  of cleaner head  51 C a hollow interior space  246  which has a shape approximating that of a short rectangularly-shaped block. Hollow interior space  246  functions as a vacuum plenum in which the air pressure therein is reduced below atmospheric pressure when the plenum is coupled to a source of negative pressure such as a vacuum pump. Thus, vacuum broom cleaner head  51  includes a swivelable union  247  for hermetically coupling plenum  246  of housing  240  to the bore  248 A of an elongated hollow tubular handle  248 , which is in turn hermetically coupled to a vacuum source such as vacuum hose  58 , as shown in  FIG. 1 . 
   As shown in  FIGS. 25 and 26 , swivelable union  247  for coupling handle  248  to housing  240  of cleaner head  51  includes a generally semi-cylindrically-shaped, bifurcated saddle boss  249  which has a longitudinal axis parallel to the upper surface  250  of upper housing wall panel  241 . As may be seen bests by referring to  FIG. 26 , saddle boss  249  has left and right parallel laterally spaced apart semi-cylindrically shaped halves  252 ,  253  which are joined together by a front web  254 , and formed between opposed inner facing left and right vertical wall surfaces  255 ,  256 , thereof a vertical slab-shaped slot  257 . 
   As shown in  FIG. 26 , saddle boss  249  has in a vertical longitudinal section the shape of a cylindrical shell, including an outer cylindrical wall  257 , and a coaxial inner wall  258  spaced radially inwardly from the outer cylindrical wall to form between the walls a pair of front and rear cylindrically-shaped grooves  259 F,  259 B. As is also shown in  FIG. 26 , boss  249  is bisected into two circumferentially-spaced apart sectors, including a front semi-cylindrically shaped sector  260  which protrudes upwardly from upper surface  250  of upper wall panel  241 , and a circumferentially spaced apart rear semi-cylindrically shaped sector  261  which is located rearward of the front sector. As shown in  FIG. 26 , rear sector  261  protrudes below lower surface  262  of upper wall panel  241 , and has a laterally disposed end wall  263  which joins outer and inner semi-cylindrically shaped walls  257 ,  258  and closes rear groove  259 B therebetween. 
   As is also shown in  FIG. 26 , tubular handle  248  of cleaner head  51 C has formed in a front, lower end thereof front and rear semi-cylindrically shaped flanges  264 ,  265  which fit relatively tightly but swivelably within front and rear semi-cylindrically shaped grooves  259 F,  259 B, respectively. Thus constructed swivelable union  249  enables handle  248  to be swivelled in a vertical plane relative to housing  240  of cleaner head  51 C, communicating negative pressure from bore  248 A of the handle to hollow interior space or plenum  246  of the cleaner head. 
   As may be seen best by referring to  FIGS. 26-29 , cleaner head  51 C includes a generally rectangularly-shaped brush block  270  which is mounted in a lower rectangularly-shaped opening  271  of housing  240 . As shown in  FIG. 29 , bottom opening  270  of housing  240  is preferably coextensive with a rectangularly-shaped space formed between inner wall surfaces of left, right and rear flange walls  242 ,  243 ,  244 , respectively, but is spaced rearward from front lower wall and closed by a transversely disposed, inverted and reversed L-shaped vertical inner flange wall  272  which is disposed transversely between inner wall surfaces of left and right flange walls  242 ,  243 . 
   As shown in  FIG. 26 , inner flange wall  272  has at the upper end thereof a rearwardly protruding transversely disposed, horizontal front retainer rib  273  which is vertically aligned with transversely disposed rear retainer rib  274  that protrudes forward from inner wall surface  275  of rear flange wall  244 . The fore-and-aft spacing between opposed vertical faces of front and rear retainer ribs  273 ,  274  is less than the fore-and-aft length of brush block  270 , thus providing ledges which limit upward motion of the brush block into opening  270 . 
   As is shown in  FIGS. 26 and 28 , inner front facing wall surface  275  of rear flange wall  244  has formed therein a short distance above lower edge wall  276  of the rear flange wall, a transversely disposed rectangular cross-section groove  278 . Rear flange wall  244  is made of an elastically deformable material, and may be flexed rearwardly to enable groove  278  to receive and elastically retain a transversely disposed rib  278  which protrudes rearwardly from rear surface  279  of brush block  270 . Also, front surface  280  of brush block  270  has protruding therefrom a transversely disposed, rectangular cross-section rib  281  which is elastically engaged within a groove  282  formed in rear wall surface  283  of inner elastically flexible flange wall  273 . 
   As shown in  FIGS. 26 ,  27  and  29 , brush block  270  has formed through its thickness dimension a plurality of vacuum passageways  285  which penetrate lower surface  286  and upper surface  287  of the brush block. As shown in  FIG. 29 , vacuum passageways  285  are arranged in a rectangular matrix which is coextensive with bottom surface  286  of brush block  270 . Brush block  270  also includes a plurality of bristle fibers  288  which protrude downwardly from lower surface  286  of the brush block. As shown in  FIG. 29 , bristles  288  are arranged in a rectangular matrix of location points which are interspersed with those of vacuum passageways  285 , thus resulting in a composite rectangular matrix in which bristles alternate with vacuum passageways. 
   Referring to  FIGS. 25-29 , it may be seen that cleaner head  51 C may optionally be provided with a transversely disposed valve  290  which has a transversely disposed vertical valve plate  291 , located in bottom open space  246  of housing  240 , rearward of front flange wall  245 . Valve  290  includes in addition to valve plate  291  an upper horizontally disposed leg  292  which is slidable fore-and-aft in a slot  293  formed between lower inner surface  294  of upper wall panel  241 , and a web  294  disposed underneath a front portion of upper wall panel  241 . Valve plate  291  is movable from a forward position, which unblocks a rectangularly-shaped front nozzle opening  295  to plenum  246 , to a rearward, closer position, by means of vertically disposed lever arm  296  which protrudes upwardly from upper horizontal leg  292  of valve  290 , through a rectangularly-shaped perforation  297  provided through upper wall panel  241 . 
     FIG. 31  illustrates a modification  51 D of cleaner head  51 C, in which front flange wall  245 D thereof has left and right sides  302 ,  303  which angle forwardly and rearwardly towards center line of the front flange wall.  FIG. 32  illustrates another modification  51 E of cleaner head  51 C, in which sides of front flange wall  51 E thereof have convex, arcuately curved shapes.