U.S. patent number RE37,081 [Application Number 09/221,800] was granted by the patent office on 2001-03-06 for backpack vacuum cleaner.
Invention is credited to Steen M. Eriksen.
United States Patent |
RE37,081 |
Eriksen |
March 6, 2001 |
Backpack vacuum cleaner
Abstract
A backpack vacuum cleaner comprising a housing with a
compartment for a filter bag, a connection branch for a suction
hose, a hip strap to be applied around the hips of the bearer and a
pair of shoulder straps. In order to only limit as little as
possible the freedom of movement of the bearer with respect to the
upper part of his body and arms when using the vacuum cleaner, and
at the same time to provide a vacuum cleaner with a comparatively
big filter bag and a subsequent big cleaning capacity, the housing
is divided in two, the two parts being connected with a flexible
connection allowing a tilting movement between the two parts, the
hip strap being fastened to the lower part and the shoulder straps
being mutually interconnected with an equalizing device for
equalizing differences in tension between the two straps.
Inventors: |
Eriksen; Steen M. (Copenhagen
NV, DK) |
Family
ID: |
26916150 |
Appl.
No.: |
09/221,800 |
Filed: |
December 28, 1998 |
PCT
Filed: |
May 27, 1994 |
PCT No.: |
PCT/DK94/00208 |
371
Date: |
November 26, 1995 |
102(e)
Date: |
November 28, 1995 |
PCT
Pub. No.: |
WO94/27485 |
PCT
Pub. Date: |
December 08, 1994 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
553282 |
Nov 28, 1995 |
05588177 |
Dec 31, 1996 |
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Current U.S.
Class: |
15/327.5;
15/352 |
Current CPC
Class: |
A47L
5/36 (20130101) |
Current International
Class: |
A47L
5/36 (20060101); A47L 5/22 (20060101); A47L
005/36 () |
Field of
Search: |
;15/327.5,352,339 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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481 229 |
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Apr 1948 |
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BE |
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325267 |
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Mar 1935 |
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IT |
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Other References
Scott Water-Vak with power discharge, Scott Industries, Scott
Aviation Corporation, New York, Form No. SAC-SALES-5066A Sep.
1966..
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Primary Examiner: Moore; Chris K.
Attorney, Agent or Firm: Kamrath; Alan Oppenheimer Wolff
& Donnelly LLP
Claims
I claim:
1. A backpack vacuum cleaner comprising a housing enclosing a motor
and an impeller to provide the suction effect and with a
compartment for a filter bag, a connection branch for a suction
hose, a hip strap to be applied around the hips of the bearer and a
pair of shoulder straps, wherein the housing is divided in upper
and lower parts connected with a flexible connection allowing a
tilting movement between said upper and lower parts, said hip strap
being fastened to the lower housing part and said shoulder straps
extending from said lower housing part to said upper housing part
and being mutually interconnected by means of an equalizing device
for equalizing differences in tension between the straps in the
pair of shoulder straps.
2. A vacuum cleaner according to claim 1, wherein the upper part of
the housing holds the filter bag, and the lower part holds the
motor, impellers for conveyance of air through the vacuum cleaner,
and means for power supply comprising one or more of the following
parts: batteries, battery charger, a coupling for the charging
adapter, a main cable connection and cable clamp.
3. A vacuum cleaner according to claim 2, wherein the hip strap at
its connections to the lower part of the housing forms an angle (v)
with the center plane of the vacuum cleaner of
60.degree.-75.degree..
4. A vacuum cleaner according to claim 1, wherein the hip strap at
least at one of its connections to the lower part of the housing
comprises at least one biasing means adapted to allow the pulling
out of a predetermined length of the hip strap under resilient
tension.
5. A vacuum cleaner according to claim 4, wherein the biasing means
is a self-winding, spring-driven storing coil.
6. A vacuum cleaner according to claim 1, wherein the equalizing
device of the shoulder strap comprises a connection for tensional
transfer between the two shoulder straps at their connection to the
lower part of the housing, preferably in form of a duct extending
through the housing, through which duct a band connecting or
uniting the two shoulder straps is displaceable.
7. A vacuum cleaner according to claim 1, wherein the shoulder
straps comprise at least one biasing means adapted to allow the
pulling out of a predetermined length of the shoulder straps under
resilient pressure.
8. A vacuum cleaner according to claim 7, wherein the sum of the
resilient tensional forces on the two shoulder straps is less than
the weight of the vacuum cleaner.
9. A vacuum cleaner according to claim 7, wherein the biasing means
for the shoulder straps comprise a pair of self-winding,
spring-driven storing coils mounted on a common shaft.
10. A vacuum cleaner according to claim 1, wherein the flexible
connection of the housing comprises a torsionally rigid tubular
bushing of an elastomeric material and with an interior clear,
through which the compartment for the filter bag is connected with
the inlet to the impellers of the motor, the motor shaft being
preferably mounted coaxially with the axis of the bushing.
11. A vacuum cleaner according to claim 1, wherein the two parts of
the housing are provided with areas adapted to rest against the
back of the bearer, said areas being placed in such a relationship
to one another that they form an angle (w) of
5.degree.-20.degree..
12. A vacuum cleaner according to claim 1, wherein the areas of the
housing in contact with the back of the bearer are provided with
substantially hemispherical knobs..Iadd.
13. A backpack vacuum cleaner comprising, in combination: a lower
housing part enclosing a motor and an impeller connected to the
motor; an upper housing part divided from the lower housing part
and enclosing a filter bag and including a coupling for a suction
hose; a hip strap fastened to the lower housing part and to be
applied around the hips of the bearer, with the upper housing part
resting on the lower housing part allowing tilting movement between
the upper and lower housing parts, so that the major part of the
weight of the vacuum cleaner is carried by the hip strap, with the
upper housing part being prevented from tilting away from the back
of the bearer, with the impeller connected to the motor sucking in
air through the filter bag of the upper housing
part..Iaddend..Iadd.
14. A vacuum cleaner according to claim 13, wherein the upper
housing part rests on the lower housing part through a flexible
connection allowing angular movement between the upper and lower
housing parts..Iaddend..Iadd.
15. A vacuum cleaner according to claim 14, wherein the flexible
connection comprises a torsionally rigid bushing of an elastomeric
material..Iaddend..Iadd.
16. A vacuum cleaner according to claim 15, wherein the torsionally
rigid bushing is tubular with an interior clear, through which the
air sucked by the impeller passes between the upper and lower
housing parts..Iaddend..Iadd.
17. A vacuum cleaner according to claim 13, wherein the upper
housing part is prevented from tilting away by first and second
shoulder straps extending from at least the upper housing
part..Iaddend..Iadd.
18. A vacuum cleaner according to claim 17, further comprising, in
combination: means for providing flexible tensioning of the first
and second shoulder straps..Iaddend..Iadd.
19. A vacuum cleaner according to claim 18, wherein the flexible
tensioning means comprises first and second storing coils provided
with means for biasing the shoulder straps and which tries to wind
up the shoulder straps..Iaddend..Iadd.
20. A vacuum cleaner according to claim 19, wherein the first and
second storing coils are mounted on a common
shaft..Iaddend..Iadd.
21. A vacuum cleaner according to claim 18, wherein the first and
second shoulder straps extend from the lower housing part and are
provided with an equalizing device placed at the connection of the
straps with the lower housing part..Iaddend..Iadd.
22. A vacuum cleaner according to claim 21, wherein the equalizing
device comprises a duct extending through the lower housing part,
through which duct a band connecting or uniting the two shoulder
straps is displaceable..Iaddend..Iadd.
23. A vacuum cleaner according to claim 13, wherein the hip strap
at its connections to the lower housing part forms an angle (v)
with the center plane of the vacuum cleaner of
60.degree.-75.degree...Iaddend..Iadd.
24. A vacuum cleaner according to claim 13, wherein the upper and
lower housing parts are provided with areas adapted to rest against
the back of the bearer, said areas being placed in such a
relationship to one another that they form an angle (w) of
5.degree.-20.degree...Iaddend..Iadd.
25. A vacuum cleaner according to claim 13, wherein the areas of
the upper and lower housing parts in contact with the back of the
bearer are provided with substantially hemispherical
knobs..Iaddend..Iadd.
26. A backpack vacuum cleaner comprising, in combination: a housing
enclosing a motor and an impeller to provide the suction effect and
with a compartment for a filter bag; a connection branch for a
suction hose; a hip strap to be applied around the hips of the
bearer; and a pair of shoulder straps, wherein the housing is
divided in upper and lower parts connected with a flexible
connection allowing a tilting movement between said upper and lower
parts, said hip strap being fastened to the lower housing part and
said shoulder straps extending from at least said upper housing
part..Iaddend..Iadd.
27. A vacuum cleaner according to claim 26, wherein the hip strap
at its connections to the lower part of the housing forms an angle
(v) with the center plane of the vacuum cleaner of
60.degree.-75.degree...Iaddend..Iadd.
28. A vacuum cleaner according to claim 26, wherein the hip strap
at least at one of its connections to the lower part of the housing
comprises at least one biasing means adapted to allow the pulling
out of a predetermined length of the hip strap under resilient
tension..Iaddend..Iadd.
29. A vacuum cleaner according to claim 26, further comprising, in
combination: biasing means adapted to allow the pulling out of
predetermined lengths of the shoulder straps under resilient
pressure..Iaddend..Iadd.
30. A vacuum cleaner according to claim 29, wherein the sum of the
resilient tensional forces on the two shoulder straps is less than
the weight of the vacuum cleaner..Iaddend..Iadd.
31. A vacuum cleaner according to claim 26, wherein the flexible
connection of the housing comprises a torsionally rigid tubular
bushing of an elastomeric material and with an interior clear,
through which the compartment for the filter bag is connected with
the inlet to the impeller of the motor, the motor shaft being
mounted coaxially with the axis of the bushing..Iaddend..Iadd.
32. A vacuum cleaner according to claim 26, wherein the two parts
of the housing are provided with areas adapted to rest against the
back of the bearer, said areas being placed in such a relationship
to one another that they form an angle (w) of
5.degree.-20.degree...Iaddend..Iadd.
33. A vacuum cleaner according to claim 26, wherein the areas of
the housing in contact with the back of the bearer are provided
with substantially hemispherical knobs..Iaddend..Iadd.
34. A vacuum cleaner according to claim 26, wherein said shoulder
straps are mutually interconnected by means of an equalizing device
for equalizing differences in tension between the straps in the
pair of shoulder straps..Iaddend..Iadd.
35. A vacuum cleaner according to claim 34, wherein the equalizing
device of the shoulder strap comprises a connection for tensional
transfer between the two shoulder straps in a form of a duct
extending through the housing, through which duct a band connecting
or uniting the two shoulder straps is
displaceable..Iaddend..Iadd.
36. A backpack vacuum cleaner comprising, in combination: a housing
enclosing a motor and an impeller to provide the suction effect and
with a compartment for a filter bag; a connection branch for a
suction hose; a hip strap to be applied around the hips of the
bearer; and a pair of shoulder straps, wherein the hip strap is
connected to the housing and includes at least one biasing means
adapted to allow the pulling out of a predetermined length of the
hip strap under resilient tension, and wherein the shoulder straps
are connected to the housing and include at least one biasing means
adapted to allow the pulling out of a predetermined length of the
shoulder straps under resilient pressure..Iaddend..Iadd.
37. A vacuum cleaner according to claim 36, wherein the housing is
divided in upper and lower parts, said hip strap being fastened to
the lower housing part and said shoulder straps extending from at
least said upper housing part..Iaddend..Iadd.
38. A vacuum cleaner according to claim 37, wherein the upper and
lower parts are connected with a flexible connection allowing a
tilting movement between said upper and lower
parts..Iaddend..Iadd.
39. A vacuum cleaner according to claim 38, wherein the hip strap
at its connections to the lower part of the housing forms an angle
(v) with the center plane of the vacuum cleaner of
60.degree.-75.degree...Iaddend..Iadd.
40. A vacuum cleaner according to claim 36, wherein said shoulder
straps are mutually interconnected by means of an equalizing device
for equalizing differences in tension between the straps in the
pair of shoulder straps..Iaddend..Iadd.
41. A vacuum cleaner according to claim 40, wherein the equalizing
device of the shoulder strap comprises a connection for tensional
transfer between the two shoulder straps in a form of a duct
extending through the housing, through which duct a band connecting
or uniting the two shoulder straps is
displaceable..Iaddend..Iadd.
42. A backpack vacuum cleaner comprising, in combination: a housing
enclosing a motor and an impeller to provide the suction effect and
with a compartment for a filter bag; a connection branch for a
suction hose, with the housing including a wall for facing the
bearer; and at least one strap for carrying the housing with the
wall being against the bearer, with the wall including projections
for providing air circulation between the wall of the housing and
the bearer..Iaddend..Iadd.
43. A vacuum cleaner according to claim 42, wherein the strap
includes biasing means adapted to allow the pulling out of a
predetermined length of the strap under resilient
tension..Iaddend..Iadd.
44. A vacuum cleaner according to claim 42, wherein the strap is a
hip strap and at its connections to the housing forms an angle (v)
with the center plane of the vacuum cleaner of
60.degree.-75.degree...Iaddend..Iadd.
45. A vacuum cleaner according to claim 42, wherein the projections
are hemispherical..Iaddend.
Description
The present invention relates to a backpack vacuum cleaner
comprising a housing enclosing a motor and an impeller to provide
the suction effect and with a compartment for a filter bag, a
connection branch for a suction hose, a hip strap to be applied
around the hips of the bearer and a pair of shoulder straps.
Portable vacuum cleaners adapted to be carried on the back of the
operator are well known, see for example U.S. Pat. No. 1,099,560,
in which a vacuum cleaner with two shoulder straps is disclosed. It
has also been suggested to fasten a traditional household vacuum
cleaner on wheels or runners to a frame belonging to a rucksack.
Such frames often in addition to the shoulder straps comprise a hip
strap holding the frame in a position close to the back of the
operator. Other examples of portable vacuum cleaners to be carried
on the back of the operator and in which the weight of the device
is transferred mainly to the shoulders of the operator by a pair of
straps are disclosed in FR-A-1 451 167 and in U.S. Pat. No.
4,325,162.
These devices comprising a rigid frame to which the vacuum cleaner
is connected as a unit have proven to restrict the operator in his
freedom of movement, for example to impede his ability to bend
forward or twist his body. This is uncomfortable if the operator is
to clean for example the seats in a bus, in a cinema or in an
aeroplane. To eliminate this drawback portable vacuum cleaners
carried solely by means of a hip strap have been proposed, see for
example U.S. Pat. No. 1,255,622. A drawback of this known device is
that the weight of the motor, which is the heaviest component of
the device, is not placed symmetrically with respect to the back of
the operator, and the collecting bag is suspended freely from the
outlet of the fan house. The depending dust bag will restrict the
freedom of movement of the operator in narrow passages, for example
between the rows of seats in a bus.
The object of the invention is to provide a portable vacuum cleaner
of the type mentioned by way of introduction and which provides an
improved comfort to the operator carrying the vacuum cleaner
enabling him to use it for extended periods. It is also an object
of the invention to provide a high degree of freedom of movement
for the operator so that the vacuum cleaner will not substantially
restrict the operator from bending forward or to the sides, from
twisting his body or lifting one of his arms.
This object is met according to the invention in that the backpack
vacuum cleaner is characteristic in that the housing is divided in
two, the two parts being connected with a flexible connection
allowing a tilting movement between the two parts, in that the hip
strap is fastened to the lower part and in that the shoulder straps
are mutually interconnected with an equalizing device for
equalizing differences in tension between the two straps.
The two-part housing allows the bearer to .[.band.]. .Iadd.bend
.Iaddend.forwards and sideways, because the housing can give way in
the flexible connection. The major part of the weight of the vacuum
cleaner may be carried by the hip strap which is connected with the
lower part of the housing, which provides for a comfortable weight
distribution enabling the operator to use the vacuum cleaner for
extended periods. The upper part of the housing rests, through the
flexible connection, on the lower part and in practice only has to
be prevented from tilting backwards by the shoulder straps which on
account of the equalizing device allow a practically unhindered
movement of the bearer's shoulders. The equalizing device thus
makes it possible for the bearer to freely lift one shoulder or
stretch out an arm and at the same time to twist his body.
In view of the freedom of movement of the bearer it is according to
the invention further advantageous that the upper part of the
housing holds the filter bag, that the lower part holds the motor,
impellers for conveying air through the vacuum cleaner, and means
for power supply comprising one or more of the following parts:
batteries, battery charger, a coupling for the charging adapter, a
mains cable connection, cable spooling, and cable clamp.
The design with filter bag in one part and motor and other heavy
components in the other logically leads to a symmetrical
construction of the mechanical parts of the vacuum cleaner within
the housing. The arrangement of the heaviest parts in the lower
part of the housing besides contributes to increasing the bearer's
freedom of movement of the upper part of his body.
In order to facilitate as much as possible the adaptation to
bearers of different height and stature and to prevent the hip
strap from being uncomfortably tight, and hip strap comprises
according to the invention at least at one of its connections to
the lower part of the housing at least one biasing means adapted to
allow the pulling out of a predetermined length of the hip strap
under resilient tension.
In a preferred embodiment according to the invention.Iadd.,
.Iaddend.the biasing means is a self-winding, spring-driven storing
coil.
According to the invention.Iadd., .Iaddend.it is preferable that
the hip strap at its connections to the lower part of the housing
forms an angle (v) with the centre plane of the vacuum cleaner of
60.degree.-75.degree.. In this embodiment.Iadd., .Iaddend.the hip
strap will, without being too tight against the hipbone of the
bearer and without being suspectible of sliding down, be able to
carry the weight of the components normally used in a vacuum
cleaner.
Tests have shown that in respect of the shoulders.Iadd.,
.Iaddend.the biggest freedom of movement for the bearer is
attained.[.,.]. when the shoulder straps have substantially the
same tension and consequently during the movements of the bearer
have to be of different .[.length.]. .Iadd.lengths.Iaddend..
According to a preferred embodiment of the invention.Iadd.,
.Iaddend.the equalizing device of the shoulder straps comprises a
connection for tensional transfer between the two shoulder straps
at their connection to the lower part of the housing, preferably in
.Iadd.the .Iaddend.form of a duct extending through the housing,
through which duct a band connecting or uniting the two shoulder
straps is displaceable. This equalizing device substantially
equalizes the difference in tension between the shoulder straps by
changing the relation between the length of those parts of the
straps which are positioned on the front of the bearer, whereby the
straps only to a limited degree have to rub against the clothing of
the bearer. This form of equalizing is in practice very
comfortable.
To facilitate the adaptation of the vacuum cleaner to bearers of
different size and also to increase the freedom of movement of the
bearer, the shoulder straps comprise according to the invention at
least one biasing means adapted to allow the pulling out of a
predetermined length of the shoulder straps under resilient
tension.
To prevent the shoulder straps from carrying the major part of the
weight of the vacuum cleaner, when the bearer stretches upwards,
the sum of the resilient pressure on the two shoulder straps is
less than the weight of the vacuum cleaner. As the pressure on the
two shoulder straps influences the vacuum cleaner at four points,
this causes a comparatively slight tightening of the shoulder
straps which will therefore not impede the freedom of movement of
the bearer.
In connection therewith.Iadd., .Iaddend.a preferred embodiment
according to the invention is characteristic in that the biasing
means for the shoulder straps comprise self-winding, spring-driven
storing coils mounted on a common shaft. By this embodiment.Iadd.,
it .Iaddend.is ensured that at any time the same length of the
shoulder straps will be pulled out or wound up and that the upper
part of the housing therefore only to a slight extent will be
susceptible of displacing itself in relation to the middle of the
bearer's back, when he bends to the side.
According to a particularly advantageous embodiment of the
invention.Iadd., .Iaddend.the flexible connection of the housing
comprises a torsionally rigid tubular bushing of an elastomeric
material and with an interior clear, through which the compartment
for the filter bag is connected with the inlet to the impellers of
the motor, the motor shaft being preferably mounted coaxially with
the axis of the bushing. This embodiment ensures both sufficient
resiliency of the flexible connection and an air flow between the
two parts of the housing.
According to the invention.Iadd., .Iaddend.the two parts of the
housing have areas adapted to rest against the back of the bearer,
said areas being places in such a relationship to one another that
they form an angle of 5.degree.-20.degree.. In this
embodiment.Iadd., .Iaddend.the housing will substantially adapt to
the back of the bearer and consequently, with a given volume extend
as little as possible to the rear relative to the bearer.
It is advantageous that the areas of the housing touching the back
of the bearer are provided with substantially hemispherical knobs.
This embodiment makes a certain ventilation possible between the
housing and the garments of the bearer, which is agreeable during
the comparatively hard physical job of vacuum cleaning under
normally cramped conditions.
The invention will be described in detail in the following with
reference to the drawing, in which
FIG. 1 shows a portable vacuum cleaner according to the invention
seen from behind in perspective,
FIG. 2 shows the vacuum cleaner according to FIG. 1 in a vertical
sectional view along the II--II in FIG. 3, and
FIG. 3 shows a sectional view along the line III--III in FIG.
2.
The vacuum cleaner 1 shown in FIG. 1 is adapted to be worn by the
bearer as a kind of rucksack. The object is to give the bearer,
when using the vacuum cleaner, the biggest possible freedom of
movement and to make him able, during the vacuum cleaning, to bend
forwards and sideways, and to make it possible for the bearer to
substantially unimpededly lift one or both arms upwards. This
object is according to the invention met in that the housing of the
vacuum cleaner is in two parts and comprises a lower part 2
containing heavier mechanical parts, such as .Iadd.a .Iaddend.motor
.[.end.]. .Iadd.and .Iaddend.means for supplying the motor with
power as well as an upper part 3 adapted to contain a filter bag.
The two parts are connected by means of a flexible connection 4
adapted to allow a certain angular movement between the two parts
of the housing. Moreover, the flexible connection forms the tubular
connection which makes it possible for the impellers connected with
the motor to suck in air through the filter bag which is placed in
the upper part of the housing. On top of the upper part 3 of the
housing.Iadd., .Iaddend.a bajonet coupling 5 is provided, with
which a traditional hose can be connected. The major part of the
weight of the vacuum cleaner is carried by a hip strap, of which
one half 6 is visible in FIG. 1. The upper part of the housing is
supported and kept against the back of the bearer by means of
shoulder straps 7 which extend from the upper part of the upper
housing 3 and which are passed into an equalizing device in the
upper part of the lower housing 2 at a slot 8. The equalizing
device is in practice a transverse duct connecting the slots in the
opposite sides of the lower part of the housing, and in which the
two shoulder straps, which are just sections of a long strap, are
united. The embodiment according to the invention is suitable for a
symmetrical positioning of the various parts in the interior of the
housing, which consequently entails that the point of gravity of
the vacuum cleaner will be in the centre plane of the housing. Out
of consideration for the comfort of the bearer.Iadd., .Iaddend.the
vacuum cleaner should be designed as a light-weight construction,
and the motor should be as light and effective as possible. It is
desirable that the total weight of the vacuum cleaner is less than
4 kg.
To further increase the comfort during use of the vacuum cleaner
and to make the adaptation to users of different height and stature
as simple as possible, the straps are provided with a flexible
biasing means which partly ensures that the straps are not resting
with more pressure than necessary against the body of the bearer,
partly makes it possible to change the length during use of the
vacuum cleaner, and partly provides an immediate adaptation to
users of varying size. FIGS. 2 and 3 show sections through an
embodiment of the vacuum cleaner according to the invention and
shows how to design the means for attaining the flexible tensioning
of the straps. In FIGS. 2 and 3.Iadd., .Iaddend.the same references
are used as in FIG. 1 for the parts common to the figures. In FIG.
2 the interior side of the back wall 9 of the upper part of the
housing 3 facing the back of the user is shown. This .[.side.].
.Iadd.back .Iaddend.wall is provided with protruding ribs 10
letting air sucked through the filter bag placed in the upper
housing .Iadd.to .Iaddend.pass down .[.against.]. .Iadd.toward
.Iaddend.the flexible, tubular connection 4 between the two parts
of the housing 2,3. Moreover, the inner surface of some
hemispherical projections 11 is seen, said projections providing
air circulation between the back of the bearer and the .[.side.].
.Iadd.back .Iaddend.wall 9. The .Iadd.ends of each
.Iaddend.shoulder straps 7 are .[.on top of the upper part.].
connected with .[.each.]. their storing coil 12,13 which are
mounted on a common shaft 14 .Iadd.on top of the upper part
3.Iaddend.. The storing coils are provided with a biasing means
which tries to wind up the shoulder straps 7. The biasing means is
adapted in such a way that the shoulder straps only carry a smaller
part of the total weight of the vacuum cleaner, but is sufficiently
forceful to prevent the upper part from tilting away from the back
of the bearer. The arrangement of spring-biased storing coils is a
preferred embodiment, but other embodiments will be usable, such as
a resilient tape or the like extending along the .[.side.].
.Iadd.back .Iaddend.wall 9. It is preferable that the two shoulder
straps 7 always will be pulled out to the same extend, like in the
case of wound up straps. The two shoulder straps 7 are provided
with an equalizing device placed at the connection of the straps
with the lower part 2 of the housing. The two straps are connected
to each other through a duct along the backwall 15 of the lower
part, whereby differences in tension in the straps are
equalized.
The major part of the weight of the vacuum cleaner is carried by a
hip strap 6. The hip strap consists of two halves, which are
provided with each their half part of a buckle 16. In the same way
as the shoulder straps 7.Iadd., .Iaddend.the hip strap is connected
with the housing by means of storing coils 17, which partly wind up
the strap, when the vacuum cleaner is not in use, partly allows an
adaptation of the strap length to bearers of varying stature.
Furthermore, the storing coils ensure that the strap also during
the bearer's movements is kept sufficiently tight, in order to
prevent the vacuum cleaner from sliding down. Part of the weight of
the vacuum cleaner is transferred to the loin of the bearer through
a friction cover 18 with substantially hemispherical knobs on the
side of the backwall 15 facing the bearer. The self-winding coils
17 may be replaced by an elastic strap material.
The hip strap rests most conveniently against the hips of the
bearer if the half parts of the straps at their connection with the
lower part of the housing form an angle v with the centre plane of
the vacuum cleaner of 60.degree.-75.degree.. The hip strap is a
webbing of the kind used for safety belts in cars.
FIG. 3 is a sectional view through the vacuum cleaner in its centre
plane. Air mixed with dust is sucked into the upper part of the
housing through a hole 19 which is connected by means of .[.a.].
.Iadd.the .Iaddend.bajonet coupling .[.to a neck.]. 5 on top of the
upper part 3 of the housing. In the upper part of the housing a
conventional filter bag may be provided. The filter bag, which may
be provided with a cardboard disc around the inlet opening, is
secured against the opening of the bajonet coupling by means of a
nose 20 placed on a door 21 on the front side of the upper part 3.
Moreover, a fine filter 22 may be provided in the upper part,
through which the air is filtered before it passes through the
flexible connection 4 down into the lower part 2 of the vacuum
cleaner. The lower part contains the motor of the vacuum cleaner
which is placed in extension of the clear of the flexible
connection 4 with a view to creating good flow conditions for the
air at the inlet to an impeller 23 placed on the shaft of the
motor, said impeller providing the suction effect. The motor is
with a view to reducing the total weight of the vacuum cleaner
preferably of the compact type with a high number of revolutions.
The lower part of the housing has a front wall with a kind of
grille .Iadd.24.Iaddend., through which air may be discharged.
The upper and the lower part of the housing is placed with such a
mutual angle that the sides facing the back of the bearer form an
angle .[.v.]. .Iadd.w .Iaddend.of 5.degree.-20.degree., preferably
around .[.14".]. .Iadd.14.degree..Iaddend.. The object of the parts
forming a mutual angle is in particular that the area .[.18.]. of
the the lower part 2 is to rest against the loin of the bearer and
thereby reduce the need to tighten the hip strap, a substantial
part of the weight of the vacuum cleaner being transferred via the
friction coating.
When designing the housing.Iadd., .Iaddend.it is, in order that the
vacuum cleaner hinders as little as possible the freedom of
movement of the bearer during the vacuum cleaner, preferable that
the housing does not project more backwards relative to the back of
the bearer than 11-12 cm, that the lower housing to some degree
tapers downwards, for which reason it will not project
substantially more backwards when the bearer bends forwards than
when he is standing straight, and that the upper housing is narrow
and slim at the shoulder blades of the bearer. The upper part of
the housing should not be so tall that it reaches the shoulder
level of the bearer.
The compact motor only takes up a smaller part of the lower part 2
of the housing. Part of the remaining volume is according to a
preferred embodiment of the vacuum cleaner used for rechargeable
batteries which deliver the required electric power for operating
the motor. According to the preferred embodiment.Iadd.,
.Iaddend.the package of batteries may further be fastened to the
front and under side of the lower part, said front and under side
thereby becoming a replaceable unit which can be replaced by
another similar unit, if the vacuum cleaner job requires more
energy than can be contained in a single battery package. The lower
part of the housing is preferably designed in such a way that the
vacuum cleaner, when not in use, is placed in an adapter containing
transformer and power control for use when .[.charching.].
.Iadd.charging .Iaddend.the batteries contained in the lower part
of the housing.
However, the invention is not limited to a battery-driven vacuum
cleaner even though the concept of a portable vacuum cleaner is
most preferable in connection with a cord free embodiment. The
excess space in the lower part of the housing may in an electric
mains operated version be used for the holding of a cord loop which
moderates the extra pull in the cord if it gets stuck when the
bearer moves during the cleaning. A cable drum may be provided in
the housing, said drum winding by means of a spring a major or
smaller part of the length of the cord at disposal.
* * * * *