Surface cleaning apparatus
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.