Abstract:
A pair of flexible sealing members connected to a housing adjacent an intake chamber to engage and form a seal with interior portions of a door opening of a vehicle is provided. This air-sealed engagement permits an orderly and efficient flow of air between the interior portions of the vehicle and the intake chamber when air is evacuated from the housing. The resulting air flow through the interior of the vehicle removes dust and debris therefrom.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to systems for forcing a high velocity air flow through an enclosure such as the interior of a bus or other vehicle for removing dirt and trash therefrom. More particularly, the invention relates to a system which includes a pneumatically controlled bellows for engaging a bus door or bus door opening to place the interior of the bus in communication with a housing containing a fan for drawing air through the bus to carry dirt and trash from the bus interior to the housing. 
     Prior art bus cleaning systems include a frame which fits over a bus door opening. Such frames are unuseable with certain types of bus doors, particularly those which open outwardly. 
     Accordingly, there is a need in the art for a system for cleaning vehicles such as buses with the cleaning system being useable with any of the bus doors or bus door openings currently in use. 
     SUMMARY OF THE INVENTION 
     The present invention includes a pair of normally closed bellows members attached to a housing adjacent an intake chamber. The housing is mounted on rails in order to insert the sealing members into an open bus door opening. A pneumatic control system controls the position of the housing on the rails and opens the sealing members against the open door, or door opening depending upon the structure of the door, to form a seal so that air may be drawn through a second door at the opposite end of the bus to blow dust and debris out of the bus into the intake chamber. 
     The system includes a start switch which is preferably located just above the opening into the intake chamber so that if the bus is positioned in alignment with the intake opening and adjacent the housing, an operator may operate the system from inside the bus. The pneumatic control system includes logic circuitry which first moves the sealing members inside the bus door opening and then opens the sealing members into contact with the bus door opening. The sealing members begin to open either after the control logic detects a predetermined pressure between the housing and the bus or after the housing has moved a maximum permissible distance along the rails toward the bus. 
     After the bus and sealing members are properly engaged, the operator turns on a fan which creates a high-velocity stream of air through the bus, which carries dust and other debris out of the bus into the housing. 
     The system may in addition include a high-pressure hose connected to a suitably high-pressure source of air so that an operator may direct a stream of compressed air on interior surfaces of the bus to dislodge dust and dirt therefrom. 
     The invention may include upper and lower bumpers which engage the upper and lower portions of the bus door opening to prevent damage to the bus and to prevent injury to a person who may be inadvertently caught between the housing and the bus. The sealing members are preferably constructed of a flexible material to conform to the shapes of surfaces against which the sealing members are pressed. The pneumatic control system pushes the bumpers against the bus and opens the sealing members against the bus door opening with forces which provide adequate sealing but which are low enough to prevent injury to persons which may be between the bus cleaning apparatus and the bus. 
     The housing is preferably pivotally mounted on a plate so that the housing rotates to disengage the sealing members from the bus if the bus should move forward or backward. A shear pin retains the housing against rotation when a torque less than a predetermined value acts upon the housing about the pivotal mounting. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a bus approaching the bus cleaning apparatus according to the invention; 
     FIG. 2 is a perspective view of the invention; 
     FIG. 3 is an exploded perspective view of a portion of the invention; 
     FIG. 4 is a partial cross sectional view taken along line 4--4 of FIG. 2; 
     FIG. 5 is a cross sectional view taken along line 5--5 of FIG. 2; 
     FIG. 6 is a side elevation view; 
     FIG. 7 is a plan view of the invention; and 
     FIG. 8 is a block diagram of the pneumatic control system of the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 shows a bus 10 approaching a bus cleaning system 12 according to the invention. The bus 10 is positioned for cleaning such that a door 14, preferably near the front of the bus 10, is in alignment with an intake opening 16 shown in FIG. 2 in a housing 18. The bus 10 normally has a rear door 15. 
     Referring to FIGS. 3, 4 and 7, a pivot pin 20 provides means for pivotally mounting a floor plate 21 of the housing 18 on a plate 22. The plate 22 is mounted on a pair of rails 24 and 26 for movement thereon. Suitable means for mounting the plate 22 to the rails 24 and 26 may include a first pair of bearing assemblies 28 and 30 fixed to a side 32 of the plate 22 for engagement with the rail 24 and a second pair of bearing assemblies 34 and 36 fixed to a side 38 of plate 22 for engagement with the rail 26. The rails 24 and 26 are fixed by any suitable means, such as welding, to a base 40. 
     A bracket 42 extends from the base 40 and provides means for connecting a dual action linear actuator 44, preferably pneumatically controlled, to the base 40. As shown in FIG. 4, a second bracket 46 extends from the plate 22 to provide means for connecting the dual action linear actuator 44 thereto. In the illustrated embodiment, the dual action linear actuator 44 has an actuator housing 48 connected to the bracket 42 and an actuator rod 50 connected to the bracket 56. 
     A pneumatic control system 52 shown in FIG. 8, located in a control housing 54 provides pneumatic pressure to the dual action linear actuator 44 to control movement of the housing 18 along the rails 24 and 26. 
     A pair of lower bumpers 56 and 58 are attached to a plate 59 which extends from the plate 21 below the intake opening 16, and an upper bumper 60 is attached to the upper portion of the housing 18. As shown in FIG. 6, the lower bumpers 56 and 58 and the upper bumper 60 contact bus 10 at the upper and lower portions of a bus door opening 64, respectively, when the housing 18 is in position for the cleaning bus 10. 
     Referring to FIG. 2, in order to use the bus cleaning system 12, an operator positions the bus 10 such that the bus door opening 64 is in alignment with the intake opening 16 and preferably within less than a predetermined distance, related to the range of movement of housing 18 along rails 24 and 26 from the bus cleaning system 12. To initiate the cleaning action, the operator actuates a start switch 61 located in a panel 62 above intake opening 16 of the housing 18. The start switch 61 is accessible to the operator from the interior of the bus 10 if the bus door 14 is open while the bus 10 is properly positioned relative to the intake opening 16. Actuation of the switch 61 causes the pneumatic control system 52 to move the housing 18 forward along the rails 24 and 26 until the lower bumpers 56 and 58 and the upper bumper 60 contact the bus 10 or until the housing 18 has traveled a predetermined maximum permissible distance along the rails 24 and 26. 
     Referring to FIGS. 2, 5 and 7, a pair of sealing flaps or members 66 and 67 are connected to the housing 18 in alignment with the sides of intake opening 16. A pair of hinges 68 and 69 pivotally mount the sealing members 66 and 67, respectively, to the housing 18. The sealing members 66 and 67 are normally in a closed position. A dual action linear actuator 70, preferably pneumatically controlled, mounted between the sealing member 66 and a panel 71 which extends from the panel 62 controls the angular position of the bellows member 66 relative to the housing 18. Similarly, a dual action linear actuator 72, also preferably pneumatically controlled, connected between the sealing member 67 and the housing 18 controls the angular position of the sealing member 67 relative to the housing 18. Both dual action linear actuators 70 and 72 receive pneumatic pressure from the pneumatic control system 54. 
     The pneumatic control system 54 controls the angular positions of the sealing members 66 and 67 such that at a predetermined time after the upper and lower bumpers 56 and 58 and the upper bumper 60 exert a predetermined pressure, such as 50 pounds per square inch, on the bus 10, the pneumatic control system 54 opens the sealing members 66 and 67 relative to the intake opening 16 such that the sealing members 66 and 67 engage the corresponding inner portions of the bus door opening 64. The sealing members 66 and 67 are suitably configured for engaging the interior portions of the bus door opening 64 if the bus doors 14 open outwardly, or for engaging the exposed surfaces of the bus door 14 if the bus door 14 opens inwardly. Sealing members 66 and 67 are made of a flexible material for sealing engagement with either the bus door 14 or the bus door opening 64. The pneumatic control system 54 provides pressurized gas to the dual action linear actuators 70 and 72 such that the dual action linear actuators 70 and 72 cause the sealing members 66 and 67, respectively, to exert a predetermined pressure, such as 30 pounds per square inch, against any object which resists opening movement of the sealing members 66 and 67 relative to the intake opening 16. The pressure which the sealing members 66 and 67 exert against the bus doors 14 or the bus door opening 64 is sufficient to form an adequate seal therebetween without causing injury to the operator if portions of his body should inadvertently be in the path of the sealing members 66 and 67 as they move to engage the bus 10. 
     A shear pin 104 retains the housing 18 against rotation about the pivot pin 20 whenever a torque less than a predetermined value is applied to the housing 18 about the pivot pin 20. Thus the housing 18 remains fixed relative to the plate 22 unless an excessive torque is applied to the housing, with the bus 10. The pivot pin 20 and shear pin 73, therefore, permit the housing 18 to rotate away from the bus 10 if the bus 10 should begin to roll while the sealing members 66 and 67 are engaged therewith, thereby preventing damage to both the bus 10 and the bus cleaner system 12. 
     Referring to FIG. 8, upon actuation, the start switch 61 which is connected to a pneumatic pressure source 74, connects a pneumatic signal to an input a of a flip flop 75, which provides a control signal through an output c to a double-ported control valve 76. After receiving the control signal from the flip flop 75, the double-ported control valve 76 provides a pressurized gas to a chamber 78 of the dual action linear actuator 44 to advance the actuator rod 50, which moves the housing 18 along the rails 24 and 26 toward the bus 10. The control signal output from terminal c of the flip flop 75 is also connected to an input b of a summer 80, which also receives an input from the linear dual action actuator 44. If dual action linear actuator 44 pushes the housing 18 against the bus 10 with a predetermined force, or if the actuator rod 50 has traveled its maximum possible distance out of the actuator housing 48, while input b of the summer 80 receives the control signal output of terminal c of the flip flop 75, then summer 80 provides an output signal for opening the sealing members 66 and 67 at a terminal c to an input terminal a of a flip flop 82. The flip flop 75 provides an output at a terminal d to an input terminal f of the flip flop 82. Simultaneous application of input signals to terminals a and f of the flip flop 82 from the flip flop 75 and the summer 80, respectively, causes the flip flop 82 to output a signal at terminal c to an input terminal b of a summer 84. 
     The summer 84 has an output terminal c connected to a double-ported control valve 86, which provides a pressurized gas to a pair of chambers 87 and 88 in the dual action linear actuators 70 and 77, respectively to open the sealing members 66 and 67. The double-ported control valve 86 is connected to an input a of a summer 89, which also has an input terminal b which receives a signal from terminal c of a flip flop 90. The flip flops 82 and 90 receive pneumatic pressure from the pneumatic pressure source 74. Output c of the summer 89 is connected to input f of the flip flop 75. 
     The pneumatic control system 52 includes a reset switch 91 which, when actuated, provides an input signal to a terminal a of an AND gate 94. The AND gate 94 receives a second input at an input terminal b from output terminal c of the flip flop 82. The control signal for opening the sealing members 66 and 67 emanates from output terminal c of the flip flop 82; therefore, the pneumatic control system 52 may be reset after actuation of the start switch 61, which initiates the logic sequence for moving the sealing members 66 and 67 to the open position. Upon receipt of appropriate input signals, the AND gate 94 provides a signal to input terminal a of the flip flop 90. The f terminal of the flip flop 90 receives a signal from the d output terminal of the flip flop 82. The input signal to terminal f of the flip flop 90 is a logic high after the start button 61 has actuated the flip flop 75. Therefore, sequential actuation of the start switch 61 and reset switch 91 causes the flip flop 90 to output a signal to double-ported valve 86 through the summer 84 to vent the chambers 87 and 88 while supplying pneumatic pressure to a pair of chambers 92 and 93 of the dual action linear actuators 70 and 72, respectively to cause the sealing members 66 and 67 to move to the closed position out of engagement with the bus 10. After the sealing members 66 and 67 have moved to the fully closed position, the signal from the summer 89 to the flip flop 75 causes the double-ported control valve 76 to pressurize a chamber 96 of the dual action linear actuator 44 while venting the chamber 78 to retract the actuator rod 50 into the actuator housing 48 to move the housing 18 away from the bus 10. 
     The bus cleaning system 12 may include a high-pressure hose 98 as shown in FIGS. 1, 2 and 6 connected to a source (not shown) of pressurized air. After properly engaging the sealing members 66 and 67 with the bus 10, the operator sprays high-pressure air from the hose 98 on dust and debris inside the bus 10 to facilitate the cleaning operation. 
     A fan (not shown) in the housing 18 forces air into the open rear door 15 to create a high velocity air stream through the bus 10 to remove loose dirt and refuse therefrom. A duct 102 connects the housing 18 to a receptacle 104 which collects material removed from bus 10. The receptacle 104 is normally stationary relative to the bus 10 being cleaned; therefore a flexible duct section 106 shown in FIG. 1 connects the housing 18 to the duct 102 to permit movement of the housing 18 relative to the receptacle along the rails 24 and 26. 
     Although the invention has been described in some detail by way of illustration and example for purposes of clarity and understanding, it is understood that certain changes and modifications may be made within the spirit of the invention and scope of the appended claims.