Surface cleaning apparatus

Abstract

A surface cleaning apparatus comprises a body including a plurality of compartments. An elongate rotating brush arrangement is positioned within and extends across a first compartment. An electric motor is positioned in a second compartment for driving the brush. The motor for the brush can be operated at a plurality of speeds. A feedback loop maintains the selected speed during operation, and the motor will automatically shut off if the brush is unable to rotate.

1 . A surface cleaning apparatus, comprising: 
 a) a body having a first compartment and a second compartment;    b) an elongate brush that can be rotated extending across the first compartment;    c) an electric motor in the second compartment, said motor being capable of rotating the brush at a plurality of discrete speeds;    d) a belt connecting the motor and the brush;    e) a sensor for sensing a rotational speed of the brush; and    f) a feedback circuit operably connected to said rotational speed sensor for maintaining the rotational speed of the brush at a speed corresponding to one of the plurality of discrete speeds.    
   
   
       2 . The surface cleaning apparatus of  claim 1 , further comprising: 
 a sensor for measuring the current drawn by said motor to drive said brush as a function of time; and    an interlock circuit operably connected to said current sensor and said motor, wherein when the current drawn over a time period is measured to be greater than one of a plurality of threshold values, the interlock circuit prevents operation of the motor.    
   
   
       3 . The surface cleaning apparatus of  claim 1 , further comprising: 
 a battery operably connected to the electric motor; and    a recharging interlock to prevent operation of the motor based on the battery during a recharging period.    
   
   
       4 . The surface cleaning apparatus of  claim 3 , wherein the recharging period is from 1 hour to 24 hours.  
   
   
       5 . The apparatus of  claim 1 , wherein said first compartment is a forward compartment.  
   
   
       6 . The apparatus of  claim 5 , wherein said first compartment comprises a front wall having a thickness and having a bottom surface at a higher elevation than a bottom surface of said body, wherein said bottom surface of said front wall has a lip of increased thickness relative to said thickness of said front wall.  
   
   
       7 . The apparatus of  claim 6 , wherein said bottom surface of the front wall is inclined at an angle relative to the plane of the sweeper body.  
   
   
       8 . The apparatus of  claim 6 , wherein said front wall of said first compartment further comprises an opening for admitting larger particles into said forward compartment.  
   
   
       9 . The apparatus of  claim 1 , further comprising a wall separating the first compartment from at least one other compartment, wherein the wall is inclined rearwardly.  
   
   
       10 . The apparatus of  claim 9 , wherein the wall between the first compartment and the at least one other compartment has an angle of inclination of from 15 to 20 degrees.  
   
   
       11 . The apparatus of  claim 1 , wherein the second compartment comprises a sealing wall that seals off the second compartment from at least one other compartment in the body.  
   
   
       12 . The apparatus of  claim 1 , wherein the motor is capable of rotating the brush at 3 or more discrete speeds.  
   
   
       13 . The apparatus of  claim 12 , wherein the motor is capable of rotating the brush at a first discrete speed of from 3500 to 4000 rpm, a second discrete speed of from 2500 to 2800 rpm, and a third discrete speed of from 1900 to 2400 rpm.  
   
   
       14 . The apparatus of  claim 1 , wherein the feedback circuit comprises a proportional-integral-derivative compensated motor drive.  
   
   
       15 . A method for sweeping a surface, comprising: 
 providing a sweeper comprising: 
 a body;  
 one or more compartments in said body;  
 a brush that can be rotated in one of the compartments; and  
 a motor in a different compartment than the brush for rotating the brush,  
 the method comprising:  
   rotating said brush at one of a plurality of discrete speeds;    sensing the rotational speed of the brush; and    restoring the rotational speed of the brush to one of the plurality of discrete speeds.    
   
   
       16 . The method of  claim 15 , further comprising: 
 sensing current provided to the motor for rotating said brush;    comparing the sensed current with a plurality of stored composite current-time cutoff values; and    stopping said motor when the sensed current exceeds a current cutoff value for a time greater than the corresponding cutoff time value.    
   
   
       17 . The method of  claim 15 , wherein the motor is capable of rotating the brush at 3 or more discrete speeds.  
   
   
       18 . The apparatus of  claim 17 , wherein the motor is capable of rotating the brush at a first discrete speed of from 3500 to 4000 rpm, a second discrete speed of from 2500 to 2800 rpm, and a third discrete speed of from 1900 to 2400 rpm.  
   
   
       19 . A surface cleaning apparatus, comprising: 
 a) a body having a first compartment and a second compartment;    b) an elongate brush that can be rotated extending across the first compartment;    c) an electric motor in the second compartment, said motor being capable of driving the brush at a plurality of discrete speeds;    d) a belt connecting the motor and the brush;    e) a sensor for measuring current drawn by said motor to drive said brush as a function of time; and    f) an interlock circuit operably connected to said current sensor and said motor, wherein when the current drawn over a time period is measured to be greater than one of a plurality of composite threshold values, the interlock circuit prevents operation of the motor.    
   
   
       20 . The surface cleaning apparatus of  claim 19 , further comprising: 
 a sensor for sensing the rotational speed of the brush; and    a feedback circuit operably connected to said rotational speed sensor for maintaining the rotational speed of the brush at a speed corresponding to one of the plurality of discrete speeds.    
   
   
       21 . The surface cleaning apparatus of  claim 19 , further comprising: 
 a battery operably connected to the electric motor; and    a recharging interlock to prevent operation of the motor based on the battery during a recharging period.    
   
   
       22 . The surface cleaning apparatus of  claim 21 , wherein the recharging period is from 1 hour to 24 hours.  
   
   
       23 . The apparatus of  claim 19 , wherein the first compartment is a forward compartment.  
   
   
       24 . The apparatus of  claim 23 , wherein said first compartment comprises a front wall having a thickness and having a bottom surface at a higher elevation than a bottom surface of said body, wherein said bottom surface of said front wall has a lip of increased thickness relative to said thickness of said front wall.  
   
   
       25 . The apparatus of  claim 24 , wherein said bottom surface of the front wall is inclined at an angle relative to the plane of the sweeper body.  
   
   
       26 . The apparatus of  claim 24 , wherein said front wall of said first compartment further comprises an opening for admitting larger particles into said forward compartment.  
   
   
       27 . The apparatus of  claim 19 , further comprising a wall separating the first compartment from at least one other compartment, wherein the wall is inclined rearwardly.  
   
   
       28 . The apparatus of  claim 27 , wherein the wall between the first compartment and the at least one other compartment has an angle of inclination of from 15 to 20 degrees.  
   
   
       29 . The apparatus of  claim 19 , wherein the second compartment comprises a sealing wall that seals off the second compartment from at least one other compartment in the body.  
   
   
       30 . The apparatus of  claim 19 , wherein the composite threshold values are at least 10 amps for 1 second, at least 15 amps for 500 milliseconds, and at least 20 amps for 100 milliseconds.  
   
   
       31 . A method for sweeping a surface, comprising: 
 providing a sweeper comprising 
 a body;  
 one or more compartments in said body;  
 a brush that can be rotated in one of the compartments; and  
 a motor in a different compartment than the brush for rotating said brush,  
   the method comprising:    sensing current provided to the motor for rotating said brush;    comparing the sensed current with a plurality of stored composite current-time cutoff values; and    stopping said motor when the sensed current exceeds a current cutoff value for a time greater than the corresponding cutoff time value.    
   
   
       32 . The method of  claim 31 , further comprising: 
 rotating said brush at one of a plurality of discrete speeds;    sensing the rotational speed of the brush; and    restoring the rotational speed of the brush to said one of a plurality of discrete speeds.    
   
   
       33 . The method of  claim 31 , wherein the composite current-time cutoff values are 10 amps for 1 second, 15 amps for 500 milliseconds, and 20 amps for 100 milliseconds.