Brushing – scrubbing – and general cleaning – Machines – With air blast or suction
Reexamination Certificate
2001-11-21
2003-11-25
Snider, Theresa T. (Department: 1744)
Brushing, scrubbing, and general cleaning
Machines
With air blast or suction
C015S327600, C015S412000
Reexamination Certificate
active
06651294
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a vacuum cleaner, and more particularly, to a safety device by which a driving motor for generating suction force in a vacuum cleaner cannot be overloaded.
2. Description of the Prior Art
As shown in
FIG. 1
, a vacuum cleaner is generally constructed to comprise a main body
2
, a connecting hose
4
connected to the main body
2
, an extension tube
6
connected to the connecting hose
4
, and a suction nozzle
8
mounted to a lower end of the extension tube
6
.
A driving motor for generating suction force and a filtering device for filtering air containing foreign materials to be introduced are included in the main body
2
. The connecting hose
4
, which is manufactured in the form of a pipe made of flexible material, causes the main body
2
to be connected to the extension tube
6
. The extension tube
6
is generally constructed to be extendable and contractible. Further, a handle gripped by a user is formed at an upper portion of the extension tube.
The suction force generated from the main body
2
is transferred to the suction nozzle
8
via the connecting hose
4
and the extension tube
6
. In addition, since the suction nozzle
8
is usually used in a state where it is in contact with a surface to be cleaned, the foreign materials such as dusts on a room floor is introduced into the main body through the suction nozzle
8
together with the air. The air containing the foreign material introduced as such is introduced into the main body through the extension tube
6
and the connecting hose
4
, and then is filtered.
FIG. 2
shows an interior structure of the main body
2
of the cleaner in a state where an upper casing of the main body
2
is opened. Referring to
FIG. 2
, the interior structure of the main body will be explained. As shown in this figure, a dust-collecting chamber
22
a
into which a dust-collecting bag such as a paper bag is inserted is provided within a lower casing
21
constructing a lower portion of the main body
2
. The dust-collecting chamber
22
a
is divided by a partition
26
, while a chamber
22
b
for accommodating the motor (hereinafter, referred to as a “motor chamber”) is formed at the other side of the partition
26
. A motor housing
24
in which the motor for generating the suction force is mounted is installed within the motor chamber
22
b.
A motor cover
25
for opening and closing an upper portion of the motor housing
24
is provided with a connecting tube
25
a
that communicates with the motor chamber
22
b
located below the motor cover. Further, a dust-collecting bag (not shown) for allowing only the air, out of the air containing the introduced foreign materials, to be discharged to the outside is installed within the dust-collecting chamber
22
a
. Furthermore, a cover
28
in which a damper
28
a
is mounted is installed at an upper portion of the dust-collecting chamber
22
a
. The damper
28
a
has a construction that the damper is opened when pressure within the dust-collecting chamber
22
a
becomes lower than the atmosphere pressure, so that air outside the main body of the cleaner can be introduced into the dust-collecting chamber
22
a
. The structure of the damper
28
a
itself is well known, and thus, detailed description thereof will be omitted.
As shown in
FIG. 3
in which a connecting relationship between the connecting tube
25
a
and the partition
26
is illustrated, the connecting tube
25
a
connected to the motor cover
25
is connected to a vent hole
26
a
formed in the partition
26
, and a pressure switch
27
for sensing pressure within the dust-collecting chamber
22
a
is connected to an end of the connecting tube
25
a
. Thus, the pressure switch
27
is formed through the vent hole
26
a
so that it can sense the pressure within the dust-collecting chamber
22
a.
The suction pressure generated when the motor installed within the motor housing
24
starts to operate is transferred to the suction nozzle
8
, and consequently, the foreign materials such as dusts remaining on the room floor are introduced into the main body
2
through the suction nozzle
8
. Further, only the air out of the air containing the foreign materials, which has been introduced into the dust-collecting bag inserted into the dust-collecting chamber within the main body, flows from the dust-collecting bag. Thus, the foreign materials such as dusts are gradually collected within the dust-collecting bag.
In addition, the air flowing from the inside to the outside of the dust-collecting bag passes through the interior of the motor housing
24
, and is discharged to the outside of the cleaner. The reason why the air passes through the interior of the motor housing
24
is that the air should cool down the motor from which heat is generated during its operation.
If the dusts are collected in a large quantity within the dust-collecting bag or large foreign materials are caught in any one of the connecting nozzle
8
, the extension tube
6
and the connecting hose
4
in the process of such an operation, the pressure within the dust-collecting chamber
22
a
is lowered. That is, the pressure within the dust-collecting chamber
22
a
is lowered, because the motor installed within the motor housing
24
incessantly performs its own discharge operation whereas a small quantity of the air is introduced into the dust-collecting chamber
22
a.
Then, if the pressure is lowered, the motor installed within the motor housing
24
is substantially overloaded. That is, this is because the motor discharges the air within the dust-collecting chamber while operating in such a state where the air cannot be normally introduced into the dust-collecting chamber
22
a
due to the foreign materials sucked into the dust-collecting bag inserted into dust-collecting chamber. However, such an overload is not preferable since it exerts a critical influence on the function of the cleaner.
Therefore, in this case, the pressure switch
27
mounted to sense the pressure within dust-collecting chamber
22
a
through the vent hole
26
a
in the partition
26
can sense reduction of the pressure within the dust-collecting chamber. Further, based on the pressure sensed by the pressure switch
27
, alarm lights or sounds can be produced to inform the user that the cleaner is in an abnormal state. Thus, the user can take measures such exchange of the dust-collecting bag.
On the other hand, in a case where the user cannot perceive such an alarm, the motor installed within the motor housing is continuously overloaded. Thus, the damper
28
a
mounted on the cover
28
starts to operate. That is, if the pressure within the dust-collecting chamber
22
a
is greatly lower than the outside pressure, the damper
28
a
is opened and the air outside the main body of the cleaner is then introduced into the dust-collecting chamber
22
a
so that the motor is prevented from being overloaded.
However, the vacuum cleaner constructed as such has the following problems.
The aforementioned damper
28
a
and pressure switch
27
are parts for eventually preventing the motor from being overloaded. According to the prior art mentioned above, however, the pressure switch
27
senses merely the pressure within the dust-collecting chamber
22
a
, and moreover, it measures the pressure through the connecting tube
25
a
. Thus, there is likelihood that any error in measurement of the pressure can be produced. Consequently, the pressure cannot be accurately measured.
Further, since the air introduced through the damper
28
a
is introduced into the motor housing
24
via the dust-collecting chamber
22
a
and the dust-collecting bag, a sufficient quantity of the air is not substantially introduced into the motor housing
24
. Thus, there is a disadvantage in that the motor cannot be sufficiently prevented from being overloaded.
Furthermore, the aforementioned conventional constitution is not substantially simple and requires the other components such as tubes. Thus, there is also a problem in tha
Fleshner & Kim LLP
LG Electronics Inc.
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