Broom and suction assembly for a street sweeper
BACKGROUND AND SUMMARY 
     The invention relates to vacuum street sweepers, including the motorized vehicular type having a hopper for receiving debris and a vacuum system for suctioning debris and depositing same in the hopper. 
     Known street sweeper vehicles typically have a broom and intake suction nozzle secured to the chassis of the vehicle in fixed relation, providing a fixed path of suctioned sweeping relative to the direction of vehicle movement. This construction prevents sweeping into odd corners, and prevents the sweeping of square areas. Additionally, the width of the swept path is fixed. 
     The present invention provides a vacuum street sweeper vehicle enabling the cleaning of odd corners and square areas. The swept and suctioned path may be changed relative to the direction of vehicle movement. The width of the path may also be changed, for example to minimize vehicle clearance requirements in restricted areas by making the broom path no wider than the vehicle itself. An intake broom and suction assembly on the vehicle is laterally moveable relative to the direction of travel of the vehicle. 
     Known suction transfer passages between the suction nozzle and the hopper to employ flexible rubber hoses, elongated corrugated bellows, or the like. This arrangement suffers shortended life from rapid abrasion of the relatively soft material from suctioned debris impacting therealong during its passage to the hopper. 
     In the present invention, a substantially rigid suction transfer tube, preferably a solid metal pipe, is provided between the broom and suction assembly and the hopper inlet port. A special sealing gasket is provided around the upper end of the suction tube at the hopper inlet port and permits slight rotational tilting of the tube upper end which in turn permits lateral movement of the lower end of the tube and the suction nozzle, while maintaining sealed vacuum suction power. The tube is articulated at its lower end in sleeve relation with the nozzle, and a second sealing gasket permits movement thereat. The construction affords extended life of the suction transfer passage, and permits lateral movement of the intake broom and suction assembly. 
     Known vacuum street sweepers are prone to having the incoming transfer passage clogged by bulky debris. The unclogging process typically requires the operator to stop the vehicle, leave the cab, disassemble the hose from the suction nozzle, remove the offending article of debris, and reassemble the passage. 
     In the present invention, the operator may unclog the transfer passage without leaving the cab nor disassembling and then reassembling various components. The suction transfer passage extends through the operator cab and has an openable door giving the operator access to the inside of the transfer passage for withdrawing a clogging object. This affords a faster, more efficient solution to the clogging problem endemic to vacuum street sweepers. 
     Known vacuum street sweepers typically have a broom and suction nozzle configuration wherein both the broom and nozzle are curbside midship, or the broom is curbside midship and the nozzle is in the middle of the vehicle midship, or brooms are in front and the nozzle is midship. Midship placement of the nozzle and/or brooms prevents the operator in a front mounted cab from visually monitoring suction and/or sweeping performance. A midship nozzle, and front brooms, may leave dirt streaks between the brooms and the nozzle when the vehicle turns a corner. 
     The design in the present invention enables the broom and suction assembly to be forward of the front wheels. Front pick-up permits sweeping very close to obstacles. Front pick-up when combined with front steering permits the operator previously unattainable access to odd corners. The operator cab is at the front of the vehicle and has a window in the floor giving the operator improved visibility of the intake broom and suction assembly for monitoring performance. 
     Known street sweepers typically employ circular gutter brooms with steel bristles. In order to provide rigid fixation in the appropriate planes, relatively heavy broom mechanisms are employed, with substantial weight on the broom. This increases the wear on the abrasive steel broom fiber, shortening life. 
     In the present invention, a jointed lever broom fixation design is afforded which minimizes wear on the broom fiber by means of a light weight broom mechanism, yet rigidly fixes the broom in the appropriate planes. A relatively light support structure is employed with broom-supporting arms attached to a laterally moveable broom and suction nozzle carriage at fulcrums spaced from the brooms, to minimize weight on the latter. A shaft has adjustably moveable collars along the axis thereof for fixing the brooms in the proper planes, and universal joints permitting rotation of the shaft and controlling forward pitch of the brooms. 
     The invention further provides a tight pocket between a pair of rotating brooms on opposite sides of a central suction nozzle therebetween for improved pick-up. Guide wheels on opposite sides of the suction nozzle ride adjacent the brooms and facilitate the tight pocket. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevation view of a vacuum street sweeper vehicle incorporating a broom and suction assembly in accordance with the invention. 
     FIG. 2 is a front view of the lower portion of the structure of FIG. 1, showing laterally shifted positions of the broom and suction assembly. 
     FIG. 3 is an enlarged partially sectional front view of the suction and broom assembly. 
     FIG. 4 is an enlarged partially sectional top view of the broom and suction assembly. 
     FIG. 5 is an enlarged partially sectional side view of the suction transfer tube of FIG. 1. 
     FIG. 6 is an enlarged sectional view taken along line 6--6 of FIG. 5. 
     FIG. 7 is an enlarged sectional view of the upper portion of the structure of FIG. 5. 
    
    
     DETAILED DESCRIPTION 
     There is shown in FIG. 1 a vacuum street sweeper motorized vehicle 2 having a chassis or frame 4 supported on rear wheels 6 and front steering wheels 8 on street surface 10. An operator cab 12 is on the chassis at the front of the vehicle forward of a debris-receiving hopper 14 on the chassis. Vacuum system 16 suctions debris and deposits same in the hopper. Debris is collected through an intake broom and suction assembly 18 having a pair of rotating brooms 20 and 22 on opposite sides of a central suction nozzle 24 therebetween. Debris is transferred upwardly in transfer passage 26 through cab 12 to an inlet port 28 in the front side wall of the hopper, FIGS. 1 and 5. An exhaust blower compartment 30 is above the hopper and includes a vacuum blower 32 drawing air through port 38 and then directing it rearwardly through compartment 30 for exit through exhaust port 36, which creates upward vacuum suction force through port 38 in the top wall 40 of the hopper beneath the blower, which in turn provides the rearward suction force through hopper inlet port 28. A coarse screen or perforated plate 42 extends laterally across the hopper above port 28 and below port 38 to prevent debris from reaching port 38, such that the debris settles in the bottom of hopper 14. Screen 42 permits dust and the like to pass therethrough, to maintain vacuum suctioning power. 
     Intake broom and suction assembly 18 on vehicle 2 is laterally moveable relative to the direction of travel of the vehicle, FIG. 2. Passage 26 is a substantially rigid suction transfer tube, preferably of acid-resistant stainless steel or an abrasion resistant alloy. Sealing means 44, FIGS. 5-7, is provided around the upper end of the tube at hopper inlet port 28 and permits the noted lateral movement of the lower end of the suction tube at the broom and suction assembly. Seal 44 is a resilient from a member gasket of rubber or the like around the outer perimeter of the upper end of tube 26 closing the gap to the inner perimeter of the hopper inlet port formed by square opening 46 in front hopper side wall 48. Gasket 44 lies in a substantially vertical and lateral plane and permits slight rotational tilting of the tube upper end about a longitidunal forward-rearward axis as the lower end of the tube moves laterally with the broom and suction assembly. Gasket 44 is rigidly secured and sealed along its inner and outer peripheral boundaries respectively to the upper end of tube 26 and the hopper inlet port at opening 46 by bolted templates 50 and 52 or the like. Gasket 44 flexes in its resilient material between its peripheral boundaries laterally left-right and vertically up-down, FIG. 6. A set of rollers 54 and 56 are mounted to the front hopper side wall or frame by plate 58 for supporting and guiding the upper tube end in its noted motion by means of lower arcuate runner 60 depending therefrom. The suction tube is articulated at its lower end in sleeve relation with the suction nozzle, and a second seal provided by a grooved ring gasket 62 between the tube lower end and the nozzle and permits lateral movement and upward movement of the nozzle along the tube lower end. 
     Intake broom and suction assembly 18 is forward of front wheels 8. Suction transfer passage tube 26 extends through front operator cab 12 and has an openable door 64, FIG. 5, at the bend of the tube at its narrowest point allowing access by the operator to the inside of passage 26 for unclogging the latter when necessary. Window 66 is provided in the floor of the cab enabling the operator to visually monitor the swept and suctioned street surface immediately proximate the broom and suction assembly. 
     Intake broom and suction nozzle assembly 18 is part of a laterally displaceable carriage 68 on the chassis, FIGS. 3 and 4. The carriage includes a lateral cross bar 70 supporting the pair of rotary brooms at its ends and moveably mounted to the chassis by roller bearing members 72 and 74 rigidily secured to chassis 4. Member 72 is a channel-like member depending downwardly from chassis 4, having front and rear roller bearings 76 and 78, and a bottom roller bearing 80 upon which cross bar 70 rides in its left-right lateral movement relative to the direction of forward-reverse movement of the vehicle. Bearing member 74 is comparable. A tie bar 82 extends rearwardly and connects suction nozzle tube to cross bar 70 such that the suction nozzle tube and the cross bar move laterally in unison. A second lateral cross bar 84 is rigidly mounted and fixed to chassis 4. The suction nozzle tube includes a roller 86 mounted thereto and supporting the suction nozzle tube on cross bar 84. Roller 86 is rotatable about a forward-rearward longitudinal axis on a trunion 88 secured to the suction nozzle tube such that the roller rolls laterally left-right along cross bar 84 as the carriage moves laterally. The carriage may be moved by mechanical linkage, electrical, or hydraulic means such as 90 and 92 between chassis 4 and carriage portions 94 and 96. Guide wheels 98 and 100 are provided on opposite sides of the suction nozzle riding adjacent respective brooms, facilitating a tight pocket between the brooms and the central suction nozzle. A support wheel 102 is provided at the rear of the suction nozzle. 
     Jointed lever broom fixation mechanisms 104 and 106 rigidly fix respective brooms in a left-right lateral plane and in a forward-rearward longitudinal plane relative to carriage 68. A splined shaft 108 has mounting collars 110 and 112 adjustably moveable along the axis thereof for fixing the broom in the noted planes. The collars are part of universal joints at the ends of the shaft connected respectively to a broom and central tie bar 82 of the carriage and permitting rotation of the shaft to control forward pitch of the broom. Mechanism 106 is comparable. Rotation of central splined shaft 108 may be provided by a shift linkage controlled pivotable concentric sleeve gear 116, vertical rack gear, or the like on the carriage. Support arms 118 and 120 are hinged between the carriage at 122 and 124 and respective brooms and allow free floating of the brooms in the up-down vertical plane from fulcrums 122 and 124 spaced from the brooms, to minimize weight on the latter and reduce wear on the fibers of the brooms. The brooms are rotated by hydraulic motors 126 and 128. 
     It is recognized that various modifications are possible within the scope of the appended claims.