U.S. patent application number 11/240660 was filed with the patent office on 2007-08-02 for quiet vacuum cleaner.
Invention is credited to Christopher Wayne Murray, Michael Shideler, Richard William Vinson.
Application Number | 20070174992 11/240660 |
Document ID | / |
Family ID | 37906650 |
Filed Date | 2007-08-02 |
United States Patent
Application |
20070174992 |
Kind Code |
A1 |
Murray; Christopher Wayne ;
et al. |
August 2, 2007 |
Quiet vacuum cleaner
Abstract
A light-weight, quiet vacuum cleaner assembly for a backpack
vacuum cleaner includes an air inlet for communicating with a
vacuum cleaner hose and a filter; a vacuum motor for drawing air
through the vacuum cleaner hose, air inlet, and filter; a quiet
exhaust assembly module in communication with the vacuum motor for
expelling and quieting exhaust from the vacuum motor, and wherein
the vacuum cleaner assembly weighs 2-12 lbs. and includes a flow
rate (CFM) to noise (dbA) ratio (flow rate/noise) of at least
0.6.
Inventors: |
Murray; Christopher Wayne;
(Boise, ID) ; Vinson; Richard William; (Nampa,
ID) ; Shideler; Michael; (Boise, ID) |
Correspondence
Address: |
PROCOPIO, CORY, HARGREAVES & SAVITCH LLP
530 B STREET
SUITE 2100
SAN DIEGO
CA
92101
US
|
Family ID: |
37906650 |
Appl. No.: |
11/240660 |
Filed: |
September 30, 2005 |
Current U.S.
Class: |
15/326 ;
15/327.5 |
Current CPC
Class: |
A47L 9/0081 20130101;
A47L 5/36 20130101 |
Class at
Publication: |
015/326 ;
015/327.5 |
International
Class: |
A47L 5/00 20060101
A47L005/00 |
Claims
1. A light-weight, quiet vacuum cleaner assembly for a backpack
vacuum cleaner including a backpack assembly for carrying the
vacuum cleaner assembly on a user's back, a vacuum cleaner hose for
vacuuming debris from a surface, and a filter for filtering out
vacuumed debris, comprising: an air inlet for communicating with
the vacuum cleaner hose and the filter; a vacuum motor for drawing
air through the vacuum cleaner hose, air inlet, and filter; a quiet
exhaust assembly module in communication with the vacuum motor for
expelling and quieting exhaust from the vacuum motor, wherein the
vacuum cleaner assembly weighs 2-12 lbs. and includes a flow rate
(CFM) to noise (dbA) ratio (flow rate/noise) of at least 0.6.
2. The light-weight, quiet vacuum cleaner assembly of claim 1,
wherein the vacuum cleaner assembly includes a flow rate (CFM) to
noise (dbA) ratio (flow rate/noise) of at least 1.0.
3. The light-weight, quiet vacuum cleaner assembly of claim 1,
wherein the vacuum cleaner assembly includes a suction (in.
(H.sub.2O)) to noise (dbA) ratio (suction/noise) of at least
0.6.
4. The light-weight, quiet vacuum cleaner assembly of claim 3,
wherein the vacuum cleaner assembly includes a suction (in.
(H.sub.2O)) to noise (dbA) ratio (suction/noise) of at least
1.0.
5. A light-weight, quiet vacuum cleaner assembly for a backpack
vacuum cleaner including a backpack assembly for carrying the
vacuum cleaner assembly on a user's back, a vacuum cleaner hose for
vacuuming debris from a surface, and a filter for filtering out
vacuumed debris, comprising: an air inlet for communicating with
the vacuum cleaner hose and the filter, the air inlet including an
intake area; a vacuum motor for drawing air through the vacuum
cleaner hose, air inlet, and filter; a quiet exhaust assembly
module in communication with the vacuum motor for expelling and
quieting exhaust from the vacuum motor, wherein the quiet exhaust
assembly module includes a stage of exhaust openings having a total
area and the ratio of the total area of the stage of exhaust
openings to the intake area of the air inlet is at least 3:1.
6. The light-weight, quiet vacuum cleaner assembly of claim 5,
wherein the quiet exhaust assembly module includes a motor housing
with the stage of exhaust openings therein.
7. The light-weight, quiet vacuum cleaner assembly of claim 5,
wherein the quiet exhaust assembly module includes a second stage
of exhaust openings having a total area and the ratio of the total
area of the second stage of exhaust openings to the intake area of
the air inlet is at least 3:1.
8. The light-weight, quiet vacuum cleaner assembly of claim 7,
wherein the quiet exhaust assembly module includes a quiet module
housing with the second stage of exhaust openings therein.
9. The light-weight, quiet vacuum cleaner assembly of claim 5,
wherein the quiet exhaust assembly module includes a third stage of
exhaust openings having a total area and the ratio of the total
area of the third stage of exhaust openings to the intake area of
the air inlet is at least 3:1.
10. The light-weight, quiet vacuum cleaner assembly of claim 9,
wherein the quiet exhaust assembly module includes a quiet module
cap with the third stage of exhaust openings therein.
11. The light-weight, quiet vacuum cleaner assembly of claim 5,
wherein the vacuum cleaner assembly weighs 2-12 lbs. and includes a
flow rate (CFM) to noise (dbA) ratio (flow rate/noise) of at least
0.6.
12. The light-weight, quiet vacuum cleaner assembly of claim 5,
wherein the vacuum cleaner assembly weighs 2-12 lbs. and includes a
flow rate (CFM) to noise (dbA) ratio (flow rate/noise) of at least
1.0.
13. The light-weight, quiet vacuum cleaner assembly of claim 5,
wherein the vacuum cleaner assembly weighs 2-12 lbs. and includes a
suction (in. (H.sub.2O)) to noise (dbA) ratio (suction/noise) of at
least 0.6.
14. The light-weight, quiet vacuum cleaner assembly of claim 5,
wherein the vacuum cleaner assembly weighs 2-12 lbs. and includes a
suction (in. (H.sub.2O)) to noise (dbA) ratio (suction/noise) of at
least 1.0.
15. The light-weight, quiet vacuum cleaner assembly of claim 5,
wherein the quiet exhaust assembly module includes a light-weight,
high-temperature, fire retardant foam material having a density no
greater than 0.4 lb/ft.sup.3 to attenuate the exhaust sound.
16. The light-weight, quiet vacuum cleaner assembly of claim 15,
wherein the light-weight, high-temperature, fire retardant foam
material is a high-performance polyimide foam.
17. The light-weight, quiet vacuum cleaner assembly of claim 5,
wherein the quiet exhaust assembly module includes a light-weight
foam air diffuser having a density no greater than 1.9 lb/ft.sup.3
to attenuate the exhaust sound and filter out exhaust
particles.
18. The light-weight, quiet vacuum cleaner assembly of claim 17,
wherein the light-weight foam air diffuser is a reticulated
flexible polyester urethane foam.
19. The light-weight, quiet vacuum cleaner assembly of claim 5,
wherein the quiet exhaust assembly module includes an outer
acoustic panel surrounding substantially all of the quiet exhaust
assembly module, the acoustic panel including an outer surface with
a polycarbonate sheet laminated thereto, and the polycarbonate
sheet including hoop stress therein that causes the acoustic panel
to be held in place, surrounding substantially all of the quiet
exhaust assembly module, without any adhesive.
20. A light-weight, quiet vacuum cleaner assembly for a backpack
vacuum cleaner including a backpack assembly for carrying the
vacuum cleaner assembly on a user's back, a vacuum cleaner hose for
vacuuming debris from a surface, and a filter for filtering out
vacuumed debris, comprising: an air inlet for communicating with
the vacuum cleaner hose and the filter; a vacuum motor for drawing
air through the vacuum cleaner hose, air inlet, and filter; a quiet
exhaust assembly module in communication with the vacuum motor for
expelling and quieting exhaust from the vacuum motor, wherein the
vacuum cleaner assembly weighs 2-12 lbs. and includes a suction
(in. (H.sub.2O)) to noise (dbA) ratio (suction/noise) of at least
0.6.
Description
BACKGROUND
[0001] 1. Field of the Invention
[0002] The present invention relates, in general, to vacuum
cleaners, and, in particular, to backpack vacuum cleaners.
[0003] 2. Background of the Invention
[0004] It is well-known that vacuum cleaning efficiency has been
improved through the use of backpack vacuum cleaners. A backpack
vacuum cleaner includes a backpack assembly, similar to that used
in a hiking backpack, where the vacuum cleaner assembly is carried
by a backpack frame of the backpack assembly. A vacuum cleaner hose
extends from a top of the vacuum cleaner assembly and is connected
to a vacuum cleaner wand. A distal end of the vacuum cleaner wand
includes a vacuum cleaner floor tool. In use, the cleaner carries
the backpack vacuum cleaner on his or her back using the backpack
assembly, and directs the vacuum cleaner tool for cleaning the
floor surface through the wand. Historically, much of the cleaning
performed using backpack vacuum cleaners such as that done in
office buildings or other commercial settings was done at night
time, by night-time cleaning personnel and janitors. Noise made by
the backpack vacuum cleaners was not that big of an issue because
most workers and visitors were not present during the vacuum
cleaning, so the noise would not bother workers in the office
buildings or other commercial settings. However, more recently,
there is a trend to clean during the daytime, when workers and
visitors in the office buildings or other commercial settings are
present. One of the complaints by workers and visitors in the
office buildings or other commercial settings of vacuum cleaning is
the noise. The noise sources are noises associated with the motor
and air movement noise at the vacuum tools and exhaust.
[0005] Motor noise has been addressed in the past by placing sound
absorbing materials in the flow path. This reduces the system
performance to an unacceptable level and adds weight to the vacuum
cleaner. By restricting the flow path in this manner the motor is
susceptible to overheating because it is not getting sufficient air
for cooling.
[0006] Therefore, a need exists for a vacuum cleaner, especially a
backpack vacuum cleaner, that overcomes the problems with prior art
vacuum cleaners, especially the problems with prior art backpack
vacuum cleaners.
SUMMARY
[0007] The backpack vacuum cleaner of the present invention is
light-weight and significantly reduces the noise levels associated
with the motor and air movement noise at the vacuum tools and
exhaust while maintaining good system performance. The vacuum
cleaner maintains large cross-sectional areas for exhaust flow,
allowing sufficient air flow to provide the required cooling for
the motor. The vacuum cleaner also directs the air flow to unique
foam surfaces to obtain the required sound deadening.
[0008] An aspect of the invention involves a light-weight, quiet
vacuum cleaner assembly for a backpack vacuum cleaner including a
backpack assembly for carrying the vacuum cleaner assembly on a
user's back, a vacuum cleaner hose for vacuuming debris from a
surface, and a filter for filtering out vacuumed debris. The
light-weight, quiet vacuum cleaner assembly includes an air inlet
for communicating with the vacuum cleaner hose and the filter; a
vacuum motor for drawing air through the vacuum cleaner hose, air
inlet, and filter; a quiet exhaust assembly module in communication
with the vacuum motor for expelling and quieting exhaust from the
vacuum motor, and wherein the vacuum cleaner assembly weighs 2-12
lbs. and includes a flow rate (CFM) to noise (dbA) ratio (flow
rate/noise) of at least 0.6.
[0009] Another aspect of the invention involves a light-weight,
quiet vacuum cleaner assembly for a backpack vacuum cleaner
including a backpack assembly for carrying the vacuum cleaner
assembly on a user's back, a vacuum cleaner hose for vacuuming
debris from a surface, and a filter for filtering out vacuumed
debris. The light-weight, quiet vacuum cleaner assembly includes an
air inlet for communicating with the vacuum cleaner hose and the
filter; a vacuum motor for drawing air through the vacuum cleaner
hose, air inlet, and filter; a quiet exhaust assembly module in
communication with the vacuum motor for expelling and quieting
exhaust from the vacuum motor, and wherein the vacuum cleaner
assembly weighs 2-12 lbs. and includes a suction (in. (H.sub.2O))
to noise (dbA) ratio (suction/noise) of at least 0.6.
[0010] Another aspect of the invention involves a light-weight,
quiet vacuum cleaner assembly for a backpack vacuum cleaner
including a backpack assembly for carrying the vacuum cleaner
assembly on a user's back, a vacuum cleaner hose for vacuuming
debris from a surface, and a filter for filtering out vacuumed
debris. The light-weight, quiet vacuum cleaner assembly includes an
air inlet for communicating with the vacuum cleaner hose and the
filter, the air inlet including an intake area; a vacuum motor for
drawing air through the vacuum cleaner hose, air inlet, and filter;
a quiet exhaust assembly module in communication with the vacuum
motor for expelling and quieting exhaust from the vacuum motor, and
wherein the quiet exhaust assembly module includes a stage of
exhaust openings having a total area and the ratio of the total
area of the stage of exhaust openings to the intake area of the air
inlet is at least 3:1.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The details of the present invention, both as to its
structure and operation, may be gleaned in part by the accompanying
drawings, in which like reference numerals refer to like parts, and
in which:
[0012] FIG. 1 is a perspective view of an embodiment of a quiet
backpack vacuum cleaner with a vacuum cleaner hose, vacuum cleaner
wand, and vacuum cleaner floor tool attached and the quiet backpack
vacuum cleaner shown in use on the back of a user;
[0013] FIG. 2 is perspective view of the backpack vacuum cleaner of
FIG. 1;
[0014] FIG. 3 is front elevational view of the backpack vacuum
cleaner of FIG. 1 with the back strap system, power cord assembly,
two-speed switch assembly, and paper filter bag hidden for
clarity;
[0015] FIG. 4 is a front elevational view of a quiet exhaust
assembly of the backpack vacuum cleaner with the rest of the
backpack vacuum cleaner shown in phantom;
[0016] FIG. 5 is an enlarged front elevational view of the quiet
exhaust assembly module of FIG. 4 with the exhaust air flow path
shown; and
[0017] FIG. 6 is an exploded perspective view of the quiet exhaust
assembly module of FIGS. 4 and 5.
DETAILED DESCRIPTION
[0018] With reference to FIGS. 1-6, and initially FIGS. 1-3, an
embodiment of a quiet backpack vacuum cleaner 100 will be
described.
[0019] Although the quiet vacuum cleaner 100 is shown and described
as a backpack vacuum cleaner, the features of the vacuum cleaner
100 that make it a quiet, high-performance vacuum cleaner may be
applied to additional types of vacuum cleaners such as, but not by
way of limitation, canister vacuum cleaners and upright vacuum
cleaners.
[0020] After reading this description it will become apparent to
one skilled in the art how to implement the invention in various
alternative embodiments and alternative applications. However,
although various embodiments of the present invention will be
described herein, it is understood that these embodiments are
presented by way of example only, and not limitation. As such, this
detailed description of various alternative embodiments should not
be construed to limit the scope or breadth of the present invention
as set forth in the appended claims.
[0021] With reference to FIG. 1, the quiet backpack vacuum cleaner
100 includes a vacuum cleaner assembly 110 that is carried on a
user's back via a backpack assembly 120. A vacuum cleaner hose 130
extends from a top of the vacuum cleaner assembly 110 and is
connected to a vacuum cleaner wand 140. A distal end of the vacuum
cleaner wand 140 includes a vacuum cleaner floor tool 150, which
engages the carpet or other floor surface for cleaning the
same.
[0022] With reference additionally to FIG. 2, the backpack assembly
120 includes a backpack strap system 160 connected to a vacuum
cleaner support 170, which carries the vacuum cleaner assembly 110.
The backpack strap system 160 includes shoulder straps 180 and a
waist belt 190.
[0023] The vacuum cleaner assembly 110 includes a main housing
assembly 200, a top cap hose and air inlet 210 at a top end, and an
opposite exhaust end 220. A two-speed switch assembly with switch
box 230 and a power cord assembly 240 are connected to a lower
electrical section 260 (FIG. 3) of the vacuum cleaner assembly 110
through respective cords.
[0024] With reference additionally to FIG. 3, the vacuum cleaner
assembly 110 includes an upper filter section 250 and a lower
electrical section 260. The upper filter section 250 includes an
intake filter and refuse bag 265, and a motor intake filter 280. A
lower portion of the upper filter section 250 and the lower
electrical section 260 carry a quiet exhaust assembly module
270.
[0025] With reference to FIGS. 4-6, an embodiment of the quiet
exhaust assembly module 270 will be described in more detail. The
quiet exhaust assembly module 270 includes a vacuum motor 290, an
annular gasket 300, a motor housing 310, a quiet module housing
320, acoustic panel 330, an annular director plate 340, an annular
foam air diffuser 350, an annular acoustic panel 360, and a quiet
module cap 370. Each of these quiet exhaust assembly module
components will now be described in turn below.
[0026] The vacuum motor 290 is a two-stage vacuum motor having a
cylindrical head with an underside.
[0027] The annular gasket 300 is a neoprene gasket with an adhesive
on one side. The annular gasket 300 is disposed between the
underside of the cylindrical head of the vacuum motor 290 and an
upper surface of the motor housing 310.
[0028] Threaded fasteners 380 are used to attach the vacuum motor
290 to the motor housing 310.
[0029] The motor housing 310 has a generally cylindrical wall 382
with Stage 1 elongated lateral slots 384 near a bottom of the motor
housing 310. In the embodiment shown, the motor housing 310
includes four (4) Stage 1 slots 384 with three (3) of the slots
having a dimension of 3.25 in..times.0.5 in. (3 Slots @
3.25''.times.0.5''=4.875 sq. in.), and the last slot having a
dimension of 2.25 in..times.1.0 in. (1 Slot @
2.25''.times.1.0''=2.25 sq. in.). Stage 1 air flow occurs through
these slots 384. The total area of the Stage 1 slots 384 is 4.875
sq. in.+2.25 sq. in.=7.125 sq. in. The bottom of the motor housing
310 includes a plurality of ribs 386 extending outwardly from the
wall 382. The ribs 386 include threaded bosses.
[0030] Threaded fasteners 390 threadably engage the threaded bosses
of the ribs 386 to attach the quiet module housing 320 to the motor
housing 310.
[0031] The quiet module housing 320 includes a top surface 392 with
star-shaped, radiating ridges extending therefrom. The top surface
392 of the quiet module housing 320 forms the bottom or floor of
the motor housing 310 when the quiet module housing 320 is
connected to the motor housing 310. The quiet module housing 320
has a frustoconical wall 394 with Stage 2 elongated lateral slots
396 near a top of the quiet module housing 320. In the embodiment
shown, the quiet module housing 320 includes four (4) Stage 2 slots
396 having a dimension of 3.00 in..times.0.5 in. (4 Slots @
3.00''.times.0.5''=6.0 sq. in.). Stage 2 air flow occurs through
these slots 396. As indicated above, the total area of the Stage 2
slots 396 is 6.0 sq. in.
[0032] The acoustic panel 330 includes two half-cylindrical members
with an outer surface 398. The acoustic panel 330 is made of a
unique, light-weight, high-temperature, fire-retardant foam
material. The foam material is produced in flat sheets. An adhesive
is added to a side of a flat 0.032 in. polycarbonate sheet, and the
polycarbonate sheet is laminated to a side of the flat sheet of
foam material. Two flat sheets of foam material and polycarbonate
are bent into the half-cylinder configuration shown, with the
polycarbonate sheet on the outer side of the acoustic panel 330.
The two half-cylindrical members are placed together to form a
cylinder around the quiet exhaust assembly module 270, as shown in
FIG. 5. The hoop stress in the polycarbonate sheet and acoustic
panel 330 cause the acoustic panel 330 to be held in place over the
motor housing 310, quiet module housing 320, annular director plate
340, annular foam air diffuser 350, annular acoustic panel 360, and
quiet module cap 370 without any adhesive. The unique,
light-weight, high-temperature, fire-retardant foam material of the
acoustic panel 330 provides maximum attenuation of the sound waves
in the quiet exhaust assembly module 270. The foam material used in
the acoustic panels 330 is a high-performance polyimide foam sold
as type HT-340 under the name Solimide.RTM. by INSPEC FOAMS, INC.
of Plano, Tex. For mechanical properties, the foam material has a
density (ASTM D 3574, Test A) of 0.4 lb/ft.sup.3, and a tensile
strength (ASTM D 3574, Test E) of 7 lb/in.sup.2. For thermal
properties, the foam material has a thermal conductivity (ASTM C
518 at mean temperature of 75.degree. F.) of 0.32
(BTUin)/(hrft.sup.3.degree. F.), and a continuous use temperature
(recommended maximum) of 575.degree. F. For flammability
properties, the foam material has a radiant panel flame spread
index (ASTM E 162) of 1, a non-flaming specific optical density
(ASTM E 662) of smoke of 1, a flaming specific optical density of
smoke (ASTM E 662) of 3, a flame spread index (ASTM E 84-95, Tested
at a thickness of 22 mm (0.9 in.)) of 0, a smoke developed index
(ASTM E 84-95, Tested at a thickness of 22 mm (0.9 in.)) of 10. For
steam autoclave aging properties (ASTM D 3574, Test J, Procedure J,
and Test E), the foam material has a tensile strength retained of
greater than 85% and a change in weight and dimensions of less than
3%. For acoustic properties, the foam material has the following
acoustical absorption coefficients (sabins/ft.sup.2; ASTM C 423 and
E 795, Type A Mounting) at 1 in.: 0.08 at 125 Hz, 0.22 at 250 Hz,
0.58 at 500 Hz, 0.93 at 1000 Hz, 0.94 at 2000 Hz, 0.81 at 4000 Hz.
The foam material has the following acoustical absorption
coefficients (sabins/ft.sup.2; ASTM C 423 and E 795, Type A
Mounting) at 2 in.: 0.34 at 125 Hz, 0.52 at 250 Hz, 0.86 at 500 Hz,
1.06 at 1000 Hz, 0.85 at 2000 Hz, 0.94 at 4000 Hz.
[0033] The annular director plate 340 is a thin, annular sheet of
polycarbonate material that serves as a barrier and directs air
flow towards the center of the quiet exhaust assembly module
270.
[0034] The annular foam air diffuser 350 serves to break up some
line of sight in the quiet exhaust assembly module 270 and
attenuate the air flow sound waves. The annular foam air diffuser
350 is made of a reticulated flexible polyester urethane foam that
has a completely open cell, three-dimensional structure of skeletal
strands which give them special filtering properties. The foam
material used in the diffuser 350 is sold as 20 PPI, SIF Z under
the name FOAMEX.RTM. by Foamex Technical Products of Eddystone, Pa.
The homogeneous structure of the diffuser 350 helps minimize the
possibility of open channels which could drastically affect filter
efficiency. Each cell in the medium is completely interconnected
with all surrounding cells. This allows for free passage of air and
at the same time provides high surface-area contact for impingement
of dust particles. The resilience and strength of the diffuser 350
helps prevent and strand displacement under normal operating
conditions. In the embodiment shown, the diffuser 350 includes a 20
pore size (average number of pores-per-linear-inch). At this
porosity, the diffuser 350 includes a density of 1.9 lb/ft3, a
tensile strength of 25 psi, an ultimate elongation of 320%, a tear
strength of 5.5 lb/in., a 50% compression set of 7, a 25%
compression deflection of 0.42 psi, and a 65% compression
deflection of 0.67 psi. The diffuser 350 has excellent
high-temperature characteristics. It can withstand intermittent
temperatures as high as 225.degree. F. At temperatures above
500.degree. F., the material beings to melt with decomposition and
vaporization.
[0035] The annular acoustic panel 360 is made of the same material
as the acoustic panel 330 described. The above description of the
material used in the acoustic panel 330 is incorporated by
reference here as though set forth in full.
[0036] The quiet module cap 370 includes a circular dish-like
configuration with an annular recess that receives the acoustic
panel 360. A central boss 399 receives threaded fastener 400 to
mount the quiet module cap 370 and hold the intermittent components
of the quiet module housing 320 together. The quiet module cap 370
is made of a polycarbonate material and includes eight (8) Stage 3
slots 402 having a dimension of 2.0 in..times.0.36 in. (8 Slots @
2.00''.times.0.36 in =5.76 sq. in.). Stage 3 air flow occurs
through these slots 402. As indicated above, the total area of the
Stage 3 slots 402 is 5.76 sq. in. The quiet module cap 370 and
threaded fastener 400 allow the quiet exhaust assembly module 270
to be easily field serviced. To service the quiet exhaust assembly
module 270, a user simply unscrews the threaded fastener 400, and
removes the quiet module cap 370. This provides easy access to the
components of the quiet exhaust assembly module 270 for repair or
replacement of the components. The entire quiet exhaust assembly
module 270 can also be easily replaced in this manner. As a result,
the backpack vacuum cleaner 100 is never down because of something
in the quiet exhaust assembly module 270 of the backpack vacuum
cleaner 100.
[0037] A motor control module 410 is electrically coupled to the
vacuum motor 290, two-speed switch assembly with switch box 230,
and power cord assembly 240. The motor control module 410 provides
two-speed control of the vacuum motor 290. The motor control module
410 also includes a thermal protection device for shutting off the
vacuum motor 290 when the temperature exceeds approximately
95.degree. C.
[0038] The backpack vacuum cleaner 100 will now be described in
use. When the user is in the area desired for vacuuming, the user
dons the backpack vacuum cleaner 100 using the backpack strap
system 160 in the same manner as putting on a backpack for hiking.
This is easily performed because the backpack vacuum cleaner 100 is
light-weight (2-12 lbs.). In the embodiment shown, the vacuum
cleaner assembly 110 weighs 11 lbs., 3 oz. The user's arms are
placed through the shoulder straps 180 and the shoulder straps 180
are tightened to a snug, yet comfortable condition on the user's
shoulders. The waist belt 190 is clipped together, and tightened to
a snug, yet comfortable condition around the user's waist. Prior to
or after donning the backpack vacuum cleaner 100, the plug of the
power cord assembly 240 is plugged into an electrical outlet. In an
embodiment of the backpack vacuum cleaner 100 where the backpack
vacuum cleaner 100 has an onboard power source (e.g., one or more
batteries, fuel cells), plugging the power cord assembly 240 into
an electrical outlet to power the backpack vacuum cleaner 100 may
not be necessary. The backpack vacuum cleaner 100 is switched on
using the two-speed switch assembly 230. The two-speed switch
assembly 230 is also used to control the speed of the vacuum motor
290 between a high setting and low setting. In alternative
embodiments, the backpack vacuum cleaner 100 may have a number of
settings other than two settings (e.g., 1, 3, 4, etc.).
[0039] In the embodiment shown, the backpack vacuum cleaner 100
performs (about 70 CFM with about 70 in. (H.sub.2O) of lift @ about
65 dbA on a high-speed motor setting, and about 40 CFM with about
40 in. (H.sub.2O) of lift @ about 61 dbA on a low-speed motor
setting. In a preferred embodiment, the backpack vacuum cleaner 100
includes a flow rate (CFM) to noise (dbA) ratio (flow rate/noise)
of at least 0.6 and a suction (in. (H.sub.2O)) to noise (dbA) ratio
(suction/noise) of at least 0.6. In a more preferred embodiment,
the backpack vacuum cleaner 100 includes a flow rate (CFM) to noise
(dbA) ratio (flow rate/noise) of at least 1.0 and a suction (in.
(H.sub.2O)) to noise (dbA) ratio (suction/noise) of at least
1.0.
[0040] With the vacuum motor 290 activated, air, dirt, and debris
are drawn through the vacuum cleaner floor tool 150, vacuum cleaner
wand 140, vacuum cleaner hose 130, and air inlet 210 into the
intake filter/refuse bag 265 (FIG. 3). The dirt and debris is
collected by the intake filter/refuse bag 265 and air is drawn
through the motor intake filter 280 and the vacuum motor 290.
Exhaust air is expelled out of the bottom of the vacuum motor 290,
and into the motor housing 310. The exhaust air reflects off of and
is directed radially outward along the star-shaped, radiating
ridges on the top surface 392. The exhaust air exits the motor
housing 310 through the Stage 1 slots 396. The exhaust air reflects
off of the acoustic panel 330, dampening the sound level, around
the bottom of the motor housing 310 and top of the quiet module
housing 320, and into/through the Stage 2 slots 396 of the quiet
module housing 320. The air then flows downward towards the
director plate 340, and the director plate 340 directs the air flow
radially inward and down towards the acoustic panel 360. Air flow
reflects off of the acoustic panel 360, further dampening the sound
level, and outward through the air diffuser foam 350. The air
diffuser foam 350 filters out exhaust particulates in the exhaust
air flow and further dampens the sound levels without significantly
impeding air flow. The exhaust air impinges the acoustic panel 410
as it exits the air diffuser foam. The exhaust air then flows
downward, through the stage 3 slots 402, and out of the quiet
exhaust assembly module 270.
[0041] With reference to FIGS. 2, 5, and 6, the air inlet 210 has a
1.5 in. intake diameter and an intake area of 1.77 sq. in. As
indicated above, the total bypass area for the Stage 1 slots 384 is
7.125 sq. in., the total bypass area for the Stage 2 slots 396 is
6.0 sq. in., and the total bypass area for the Stage 3 slots 402 is
5.76 sq. in. The inventors have determined that it is desirable for
the bypass areas in each stage of the quiet exhaust assembly module
270 to be at least 3 times that of the area of the air inlet 210.
This reduces friction and, thus, minimizes flow loss.
[0042] The exhaust assembly module 270 incorporates the principles
of "Line of Sight" and non-reflective surfaces to diminish sound
levels (db). In the quiet exhaust assembly module 270, the vacuum
motor 290 is encapsulated in a housing, and air flow is directed to
high-temperature acoustic foam covered surfaces and through a
condensed labyrinth of passages.
[0043] The above features minimize the weight of the backpack
vacuum cleaner 100, maximize dissipation of sound levels in the
backpack vacuum cleaner 100, and maximize air flow in the backpack
vacuum cleaner 100.
[0044] The above description of the disclosed embodiments is
provided to enable any person skilled in the art to make or use the
invention. Various modifications to these embodiments will be
readily apparent to those skilled in the art, and the generic
principles described herein can be applied to other embodiments
without departing from the spirit or scope of the invention. Thus,
it is to be understood that the description and drawings presented
herein represent a presently preferred embodiment of the invention
and are therefore representative of the subject matter which is
broadly contemplated by the present invention. It is further
understood that the scope of the present invention fully
encompasses other embodiments that may become obvious to those
skilled in the art and that the scope of the present invention is
accordingly limited by nothing other than the appended claims.
* * * * *