U.S. patent application number 12/288260 was filed with the patent office on 2009-05-14 for electric vacuum head.
Invention is credited to Horst Dilger, Dieter Kaffenberger, Thomas Lind, Klaus-Dieter Riehl, Hans-Joachim Steudtner.
Application Number | 20090119871 12/288260 |
Document ID | / |
Family ID | 39537579 |
Filed Date | 2009-05-14 |
United States Patent
Application |
20090119871 |
Kind Code |
A1 |
Dilger; Horst ; et
al. |
May 14, 2009 |
Electric vacuum head
Abstract
An electric vacuum head for a vacuum cleaner has a housing, a
cleaning device that can be driven by an electric motor disposed
within the housing in a motor chamber, a vacuum mouth on the
underside of the housing delimited by vacuum mouth edges, and a
vacuum connector. The motor chamber has at least one air entry
opening for entry of air to cool the electric motor, and at least
one air exit opening. The air exit opening is disposed on the
underside of the housing so that the cooling air that exits from
the air exit opening during operation of the electric vacuum head
enters into the vacuum mouth by way of at least one of the vacuum
mouth edges.
Inventors: |
Dilger; Horst; (Morsbach,
DE) ; Kaffenberger; Dieter; (Wiehl, DE) ;
Lind; Thomas; (Freudenberg, DE) ; Riehl;
Klaus-Dieter; (Drolshagen, DE) ; Steudtner;
Hans-Joachim; (Reichshof, DE) |
Correspondence
Address: |
COLLARD & ROE, P.C.
1077 NORTHERN BOULEVARD
ROSLYN
NY
11576
US
|
Family ID: |
39537579 |
Appl. No.: |
12/288260 |
Filed: |
October 17, 2008 |
Current U.S.
Class: |
15/415.1 |
Current CPC
Class: |
A47L 9/04 20130101 |
Class at
Publication: |
15/415.1 |
International
Class: |
A47L 9/02 20060101
A47L009/02 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 14, 2007 |
EP |
07 022 070.2 |
Claims
1. An electric vacuum head for a vacuum cleaner, comprising: a
housing; a cleaning device that is driven by an electric motor
disposed within the housing in a motor chamber; a vacuum mouth on
an underside of the housing delimited by vacuum mouth edges; and a
vacuum connector connected to the housing; wherein the motor
chamber has at least one air entry opening for entry of air to cool
the electric motor, and wherein at least one air exit opening is
disposed on the underside of the housing so that cooling air that
exits from the air exit opening during operation of the electric
vacuum head enters into the vacuum mouth by way of at least one of
the vacuum mouth edges.
2. The electric vacuum head according to claim 1, wherein there are
a plurality of air exit openings on the underside of the
housing.
3. The electric vacuum head according to claim 1, wherein the at
least one air exit opening is disposed in a depression between ribs
that run approximately perpendicular to the vacuum mouth edges.
4. The electric vacuum head according to claim 1, wherein the
cleaning device is configured as a cleaning roller disposed in a
roller chamber.
5. The electric vacuum head according to claim 1, wherein the air
exit opening is disposed in an inflow region of one of the vacuum
mouth edges.
6. The electric vacuum head according to claim 1, further
comprising a sealing lip or a brush strip on the underside of the
housing, the air exit opening being disposed between the vacuum
mouth and the sealing lip or the brush strip.
7. The electric vacuum head according to claim 1, wherein the
electric motor is designed for a maximal power consumption, under
load, of more than 50 watts.
8. The electric vacuum head according to claim 1, wherein a
cross-section of at least one of the air entry opening and the air
exit opening is adjustable.
9. The electric vacuum head according to claim 1, wherein a bypass
is disposed on the motor chamber, said bypass connecting the motor
chamber with a channel or chamber through which vacuuming air
flows, within the housing.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] Applicants claim priority under 35 U.S.C. 119 of European
Application No. 07 022 070.2 filed Nov. 14, 2007.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates to an electric vacuum head for a
vacuum cleaner, having a housing, a cleaning device that can be
driven by an electric motor disposed within the housing in a motor
chamber, a vacuum mouth on the underside of the housing delimited
by vacuum mouth edges, and a vacuum connector. The motor chamber
has at least one air entry opening for entry of ambient air, and at
least one air exit opening.
[0004] The electric vacuum head can have a rechargeable battery or
also an electrical connector to the voltage supply, by way of a
vacuum cleaner. Without restriction, the electric vacuum head can
be connected by way of a suction tube and a flexible hose, or
directly to a vacuum cleaner housing. If the vacuum head is
connected directly to the vacuum cleaner housing, the weight of the
vacuum cleaner rests on the electric vacuum head. The suction tube,
i.e. the suction mechanism, is connected with the vacuum connector.
The electric vacuum head can usually be removed from the suction
tube or the vacuum cleaner housing and can be kept available as an
accessory. Electric vacuum heads equipped with a rechargeable
battery, in particular, can be added as accessories to all kinds of
different commercially available vacuum cleaners.
[0005] 2. The Prior Art
[0006] Various versions of electric vacuum heads having the
characteristics described above are known. With these types of
electric vacuum heads, the waste heat of the electric motor must be
conducted away, in order to avoid overheating and a resulting
malfunction. With a high-power electric motor, an inefficient
electric motor, or stress peaks during cleaning operation, in
particular, fans inherent in the motor are not sufficient to pass
away the waste heat, under the installation conditions that are
usually quite restricted in space. It is therefore known to utilize
the partial vacuum produced by a vacuum cleaner to pass a secondary
air stream over the motor chamber of the electric motor, to cool
it. The electric motor has air entry openings for the entry of
ambient air, and at least one air exit opening. Leaks that are
present in any case, or specially provided cooling air openings can
be provided as air entry and air exit openings. The air exit
openings open into regions having a high partial vacuum, for
example into a tilting joint assigned to the vacuum connector or
into a vacuum channel within the housing. A corresponding
embodiment is also known from Japanese Patent No. JP 9 047 395.
[0007] An electric vacuum head is known from Japanese Patent No. JP
5 253 125, in which the cooling air of the electric motor enters
into the motor chamber through air entry openings in the housing,
and gets into a roller chamber of a brush roller through air exit
openings of the motor chamber. It is a disadvantage in this
connection that the partial vacuum that prevails in the roller
chamber, and therefore also the cooling air stream, is greatly
dependent on the floor covering.
[0008] With the known embodiments, the amount of air for the
vacuuming and the partial vacuum that prevails at the vacuum mouth
are reduced by the secondary air stream required for cooling, and
the secondary air stream that does not contribute to the vacuuming
effect is also referred to as leaking air or leakage air. Because
of the required minimum cooling air amount, a good seal is not
possible in the known embodiments of an electric vacuum head.
SUMMARY OF THE INVENTION
[0009] Against this background, it is therefore an object of the
invention to improve the vacuuming and energy efficiency of an
electric vacuum head having the characteristics described
initially. In particular, the amount of air for the vacuuming
effect is to be maximized, while guaranteeing sufficient cooling of
the electric motor.
[0010] Proceeding from an electric vacuum head having the
characteristics described above, this task is accomplished,
according to the invention, in that the at least one air exit
opening is disposed on the underside of the housing, in such a
manner that the cooling air that exits from the air exit opening
during operation of the electric vacuum head enters into the vacuum
mouth by way of at least one of the vacuum mouth edges. Usually,
approximately ambient pressure prevails at the air entry openings
of the motor chamber during vacuuming, and at least a slight
partial vacuum occurs in the region of the underside of the housing
into which the air exit opening opens. This causes air to be drawn
in from the surroundings and passed over the motor to cool it, and
to get into the vacuum mouth after it has left the air exit
openings, together with the main air stream drawn in on the
underside of the housing. According to the invention, the required
cooling air is passed over at least one of the vacuum mouth edges,
and thereby contributes to the total amount of air for the
vacuuming effect. A displacement of the air intake merely takes
place, viewed in the flow direction, for the partial air stream of
the cooling air, in front of the vacuum mouth edges. In comparison
with the known embodiments, in which the air exit opening is
connected with a tilting joint, a suction channel, or a roller
chamber, a comparatively slight partial vacuum prevails at the at
least one air exit opening on the underside of the housing, and
therefore correspondingly large flow cross-sections have to be
provided. However, this is easily possible because of the large
surface that is available at the underside of the housing.
[0011] Preferably, a plurality of air exit openings is provided on
the underside of the housing, in order to achieve a sufficiently
large flow cross-section and to avoid a malfunction in case an air
exit opening is plugged up. Preferably, multiple air exit openings
having essentially the same configuration are disposed next to one
another. Fundamentally, air exit openings can also be disposed in
front of and behind the vacuum mouth, viewed in the working
direction, depending on the designs of the electric vacuum head
and, in particular, on the placement of the electric motor. Then,
part of the total cooling air gets into the vacuum mouth by way of
the two vacuum mouth edges.
[0012] In order to guarantee a sufficient partial vacuum to
transport the cooling air at the at least one air exit opening,
this opening is preferably disposed in an inflow region of one of
the vacuum mouth edges. In the case of a usual design of the
electric vacuum head, the distance between the air exit opening and
the related vacuum mouth edge is less than 30 mm, and preferably
less than 15 mm.
[0013] If a sealing lip, brush strip, or the like is provided on
the underside of the housing, it is practical if the at least one
air exit opening is disposed between the vacuum mouth and the
sealing lip or the brush strip. In addition to the pressure
difference over the vacuum mouth edges, a further pressure drop is
also observed at the sealing lip or the brush strip, so that a
defined partial vacuum prevails between the sealing lip or the
brush strip and the related vacuum mouth edge, under usual
operating conditions.
[0014] By means of the configuration according to the invention,
the channels, chambers, and joints along the vacuuming air stream,
between the vacuum mouth and the vacuum connector, can be
configured in a particularly sealed manner, without impairing the
cooling, in order to minimize the occurrence of leakage air. For
example, rigid and articulated connections between the parts of the
electric vacuum head can be provided with seals or flexible
connection hoses.
[0015] Since the cooling air contributes to the amount of air for
the vacuuming effect, according to the invention, a particularly
high level of vacuuming efficiency can be achieved even at a great
demand for cooling air. Thus, the electric motor can easily be
designed for a maximal power consumption, under load, of more than
50 W, preferably more than 100 W, and particularly preferably more
than 200 W.
[0016] In one embodiment of the invention, the at least one air
exit opening is disposed in a depression between ribs that
preferably run approximately perpendicular to the vacuum mouth
edges. By means of the ribs that run approximately in the flow
direction, and the set-back arrangement of the air exit opening,
blockage of the air exit opening can be prevented even in the case
of a high-pile floor covering, and a sufficient air stream can be
guaranteed.
[0017] Proceeding from the embodiment of an electric vacuum head
that has been described above, further developments are possible.
For example, cooling ribs and/or a fan wheel can be disposed on the
electric motor, to support the cooling. The cross-section of the
air entry opening and/or of the air exit openings can be configured
to be adjustable, in order to allow adaptation to a changing demand
for cooling air. In this connection, adjustment of the
cross-section can take place manually or with temperature control,
and the at least one air exit opening or the at least one air entry
opening can be closed when the electric motor is shut off. It is
also possible to variably increase or reduce the size of the flow
cross-sections, as a function of different functional or power
settings of the electric motor. In this connection, an electrically
or mechanically driven shutter can be provided for changing the
cross-section. Furthermore, automatic temperature control can also
take place, by means of a temperature sensor or a shutter
controlled as a bimetal shutter.
[0018] In another embodiment of the invention, a bypass is disposed
on the motor chamber, which connects the motor chamber with a
channel through which vacuuming air flows, or a chamber through
which vacuuming air flows, within the housing. An additional air
stream can be made available by the bypass, which stream allows
emergency cooling in the case of an excessive reduction of the
cooling air stream that flows out of the at least one air exit
opening. In this connection, it is practical if the bypass is
pressure-controlled and closed during normal vacuuming operation.
If the vacuuming air stream decreases greatly on a very high-pile
carpet or if the vacuum mouth is plugged up, for example,
sufficient cooling of the electric motor may no longer be
guaranteed, under some circumstances. At the same time, the partial
vacuum in the channels and chambers within the housing through
which vacuuming air flows increases, so that emergency cooling can
be achieved by means of a bypass that opens at a predetermined
partial vacuum.
[0019] In one embodiment, there is a cleaning roller disposed in a
roller chamber and having lips or brush strips disposed in spiral
shape, to act as a cleaning device. In this connection, the
longitudinal axis of the cleaning roller is usually oriented
horizontal to the working direction of the electric vacuum head.
Multiple cleaning rollers disposed perpendicular or at a slant to
the working direction, or other types of cleaning devices can also
be provided.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Other objects and features of the present invention will
become apparent from the following detailed description considered
in connection with the accompanying drawings. It is to be
understood, however, that the drawings are designed as an
illustration only and not as a definition of the limits of the
invention.
[0021] In the drawings, wherein similar reference characters denote
similar elements throughout the several views:
[0022] FIG. 1 shows a perspective view of an electric vacuum head
according to the invention;
[0023] FIG. 2 shows the electric vacuum head according to FIG. 1 in
a view from below;
[0024] FIG. 3 shows a vertical section along the line III-III of
FIG. 2;
[0025] FIG. 4 shows the qualitative progression of the partial
vacuum .DELTA.p that prevails on the underside of the housing,
along the line A-A.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0026] Referring now in detail to the drawings, FIG. 1 shows an
electric vacuum head 1 according to the invention, in a perspective
view. The electric vacuum head 1 has a housing 2, in which an
electric motor 4 for driving a cleaning device 5 configured as a
brush roller is disposed in a motor chamber 3. The bristles of the
brush roller pass through a vacuum mouth 7 that runs on the
underside of housing 2, over the width of the electric vacuum head
1, and is delimited by a front vacuum mouth edge 6a and a rear
vacuum mouth edge 6b. Sealing lips 8a, 8b are disposed in front of
front vacuum mouth edge 6a and behind rear vacuum mouth edge 6b, in
the movement direction. In addition to display elements 9, 9', and
operating elements 10, air entry openings 11 of motor chamber 3,
for passage of air to cool electric motor 4, can be seen at the top
of the housing 2. Electric vacuum head 1 has a vacuum connector 12
for a connection to a suction tube 13 or a vacuum cleaner housing,
configured as a rotating/tilting joint. The voltage supply of
electric vacuum head 1 can take place, without restriction, by way
of a voltage source integrated into electric vacuum head 1, or by
way of a feed line from the vacuum cleaner. At its rear, electric
vacuum head 1 is supported by means of rollers 14.
[0027] As can be seen in FIG. 2, which shows a bottom view of
electric vacuum head 1, air exit openings 15 of, motor chamber 3
are disposed on the underside of housing 2, in the inflow region of
the rear vacuum mouth edge 6b, between vacuum mouth 7 and rear
sealing lip 8b. A certain partial vacuum prevails at air exit
openings 15 during vacuuming operation, so that cooling air is
drawn in through air entry openings 11 and motor chamber 3, and
after exit from the air exit openings 15, gets into vacuum mouth 7
by way of rear vacuum mouth edge 6b. In this way, the cooling air
contributes to the air stream for the vacuuming effect, which flows
into the vacuum mouth by way of vacuum mouth edges 6a, 6b, thereby
achieving optimization of the vacuuming effect, according to the
invention.
[0028] Air exit openings 15 are disposed in a row, next to one
another, at the same distance from rear vacuum mouth edge 6b, in a
depression between ribs 16 that run perpendicular to rear vacuum
mouth edge 6b. The risk of blockage of air exit openings 15 on a
carpeted floor can be reduced by ribs 16 and the set-back
arrangement of air exit openings 15.
[0029] In contrast to the embodiments known from the state of the
art, a very tight seal of electric vacuum head 1 can be achieved
even at a high power consumption of the electric motor. In this
connection, electric motor 4 is typically designed for a power
consumption, under load, of more than 50 W, preferably more than
100 W, and particularly preferably more than 200 W.
[0030] It can be seen from FIG. 3 that cooling air stream K passed
through motor chamber 3 is passed by way of vacuum mouth edges 6a,
6b, and through a roller chamber 17, to vacuum connector 12,
together with main vacuuming stream H that is drawn in at the side,
on the underside of housing 2. Different power settings of electric
motor 4 can be set using operating elements 10 shown in FIG. 1,
whereby the cross-section of air entry openings 11 is adjusted
using a related shutter 18, as a function of the power setting. If
the total air stream that enters through vacuum mouth 7 decreases
greatly, for example on a very high-pile floor covering or if
vacuum mouth 7 is plugged up, sufficient cooling can no longer be
guaranteed by cooling air stream K that flows by way of the air
entry openings and the air exit openings. At the same time, the
partial vacuum in roller chamber 17 increases as a result of the
reduced total vacuuming flow. In order to prevent overheating of
electric motor 4 in the case of such an operating state, a flap
that opens under pressure control, in the direction of roller
chamber 17, is disposed on motor chamber 3 as a bypass 19. In
normal vacuuming operation, bypass 19 is closed, and opens when a
predetermined partial vacuum is exceeded, thereby achieving
emergency cooling by means of an emergency cooling stream N that
enters directly into the roller chamber from the motor chamber.
[0031] FIG. 4 shows the partial vacuum .DELTA.p that prevails at
the underside of housing 2, viewed in the longitudinal direction.
In this connection, a maximal partial vacuum .DELTA.p.sub.max with
reference to the ambient pressure is observed in a first region I,
directly below vacuum mouth 7. The partial vacuum .DELTA.p
decreases greatly at vacuum mouth edges 6a, 6b, whereby the vacuum
effect is determined, to a decisive extent, by the flow and the
pressure distribution at vacuum mouth edges 6a, 6b. In a second and
a third region II, III between a vacuum mouth edge 6a, 6b and
related sealing lip 8a, 8b, a reduced partial vacuum is observed,
but it is sufficient to generate a cooling air stream K to cool the
electric motor 4, by way of air entry openings 11, motor chamber 3,
and air exit openings 15. In a fourth and fifth region IV, V,
outside of the sealing lips, approximately ambient pressure
prevails.
[0032] Accordingly, while only a few embodiments of the present
invention have been shown and described, it is obvious that many
changes and modifications may be made thereunto without departing
from the spirit and scope of the invention.
* * * * *