U.S. patent application number 12/100895 was filed with the patent office on 2008-10-30 for hair dryer.
Invention is credited to Kenji Kamada, Hiromitsu Miyata, Hidetoshi Nakasone.
Application Number | 20080263887 12/100895 |
Document ID | / |
Family ID | 39689467 |
Filed Date | 2008-10-30 |
United States Patent
Application |
20080263887 |
Kind Code |
A1 |
Nakasone; Hidetoshi ; et
al. |
October 30, 2008 |
HAIR DRYER
Abstract
A hair dryer with a nozzle designed to effectively spread out
the wetted hair strands for enhanced drying capability. The nozzle
is configured to have its interior space divided into a plurality
of individual ducts by a separation plane extending radially about
a center axis. A weak flow zone where no direct air flow is given
from the nozzle is formed downstream of the separation plane and
between strong flow zones respectively formed downstream of the
individual ducts to flow the forced air flow directly therefrom.
With the provision of the localized strong flow zones separated by
the weak flow zone, the nozzle can develop a waved air flow of
varying flow rate, thereby enabling to spread out the wetted hair
strands and therefore increase chances of exposing the hair to the
air flow for expediting the hair drying.
Inventors: |
Nakasone; Hidetoshi;
(Hikone-shi, JP) ; Miyata; Hiromitsu; (Hikone-shi,
JP) ; Kamada; Kenji; (Hikone-shi, JP) |
Correspondence
Address: |
Cheng Law Group, PLLC
1100 17th Street, N.W., Suite 503
Washington
DC
20036
US
|
Family ID: |
39689467 |
Appl. No.: |
12/100895 |
Filed: |
April 10, 2008 |
Current U.S.
Class: |
34/97 |
Current CPC
Class: |
A45D 20/12 20130101 |
Class at
Publication: |
34/97 |
International
Class: |
A45D 20/10 20060101
A45D020/10; A45D 20/12 20060101 A45D020/12 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 24, 2007 |
JP |
2007-114709 |
Claims
1. A hair dryer comprising: a tubular casing with a flow channel
extending along an axis of said casing; a blower mounted within
said casing to generate a forced air flow directed through said
flow channel; a tubular nozzle disposed at one axial end of said
casing in communication with said flow channel to discharge said
forced air flow out through a discharge end, said nozzle having its
center axis aligned with the axis of said casing; characterized in
that said nozzle is configured to have its interior space divided
into a plurality of individual ducts by a separation plane
extending radially about said center axis.
2. A hair dryer as set forth in claim 1, wherein said nozzle
includes a partition which extends in said separation plane to
divide said interior space into two said ducts.
3. A hair dryer as set forth in claim 1, wherein each of said ducts
is tapered to have its opening narrower towards said discharge end
than at its opposite axial end.
4. A hair dryer as set forth in claim 2, wherein each of said ducts
has its inner side wall which is defined by said partition to give
a flat face at a downstream portion of said inner side wall, said
flat face extending in parallel with said separation plane.
5. A hair dryer as set forth in claim 2, wherein each of said ducts
has its opening elongated along a diameter of said nozzle.
6. A hair dryer as set forth in claim 1, wherein said nozzle is
additionally provided with a vent disposed outwardly of said
ducts.
7. A hair dryer as set forth in claim 6, wherein said casing
includes an inner barrel which defines therein said flow channel
and defines an outer flow channel between said inner barrel and
said casing, said ducts being configured to receive said forced air
flow through said flow channel, said vent being configured to
receive said forced air flow through said outer flow channel, and a
heater being provided within one of said flow channel and said
outer flow channel.
8. A hair dryer as set forth in claim 6, wherein said vent is
configured to have its opening narrower towards said discharge end
along said center axis than at an opposite axial end.
9. A hair dryer as set forth in claim 8, wherein said vent is
configured to converge towards a point downstream of the discharge
end of said nozzle.
10. A hair dryer as set forth in claim 7, wherein said vent is
configured to have its opening narrower towards said discharge end
along said center axis than at an opposite axial end.
11. A hair dryer as set forth in claim 10, wherein said vent is
configured to converge towards a point downstream of the discharge
end of said nozzle.
Description
TECHNICAL FIELD
[0001] The present invention is directed to a hair dryer, more
particularly to a hair dryer with a nozzle specifically designed to
effectively spread out wetted hair strands for expediting hair
drying.
BACKGROUND ART
[0002] Japanese Patent Publication No. 5-137613 A discloses a hair
dryer with a nozzle which is configured to have slats for
rectification of an air flow directed towards a user's hair.
Basically, the nozzle is designed to improve hair drying
efficiency, i.e., heat transfer amount per unit time (Q) which is
determined by Q=HA.DELTA.T, where H is a heat transfer coefficient,
A is a hair contact surface area, and .DELTA.T is a temperature
difference between the hair temperature and heated air temperature.
In order to increase the heat transfer amount per unit time (Q) for
expediting the drying wetted hairs and achieving rapid drying, it
is required to increase at least one of A and .DELTA.T. However,
the increase of .DELTA.T is not suitable as it necessitates to rise
the temperature of the heated air, and brings about excessive heat
which the user feel uncomfortable and which may damage the hair.
Consequently, it is a best choice to increase the hair contact
surface area. For this purpose, the nozzle of the conventional hair
dryer is designed to increase the flow rate of the air flow.
Nevertheless, the simple increase of the flow rate is found not
effective for spreading out the wetted hair strands and increasing
the hair contact surface area, but rather brings about a pressure
loss through the nozzle. Accordingly, there has been a demand for
effectively spreading out the wetted hairs in order to increase the
hair contact surface area for rapid hair drying.
DISCLOSURE OF THE INVENTION
[0003] In view of the above problem, the present invention has been
accomplished to provide a hair dryer which is capable of
effectively spreading out the wetted hairs for enhanced drying
capability. The hair dryer in accordance with the present invention
includes a tubular casing with a flow channel extending along an
axis of the casing, a blower mounted within the casing to generate
a forced air flow directed through the flow channel, and a tubular
nozzle disposed at one axial end of the casing in communication
with the flow channel. The nozzle has its center axis aligned with
the axis of the casing to discharge the forced air flow out through
a discharge end. The feature of the present invention resides in
that the nozzle is configured to have its interior space divided
into a plurality of individual ducts by a separation plane
extending radially about the center axis. With this arrangement, a
weak flow zone where no direct air flow is given from the nozzle is
formed downstream of the separation plane and between strong flow
zones respectively formed downstream of the individual ducts to
flow the forced air flow directly therefrom. The presence of the
weak flow zone between the strong flow zones can localize the
individual strong flow zones to thereby promote spreading out the
wetted hairs, thereby assuring rapid hair drying.
[0004] The nozzle is preferred to have a partition which extends in
the separation plane to divide the interior space of the nozzle
into the two ducts. Thus, the weak flow zone can be suitably sized
by the dimension of the partition in relation to that of each duct
for optimum effect of spreading out the wetted hair strands.
[0005] Preferably, each of the ducts is tapered to have its opening
narrower towards the discharge end than at its opposite axial end
for effectively providing the strong flow zone.
[0006] Further, each of the ducts has its inner side wall defined
by the partition to give a flat face at a downstream portion of the
inner side wall. The flat face is preferred to extend in parallel
with the separation plane. The presence of the flat face is found
effective to avoid interference between the air flows discharged
respectively from the ducts.
[0007] In a preferred embodiment, each of the ducts is configured
to have its opening elongated along a diameter of the nozzle such
that the user can orient the nozzle in a direction of effectively
blowing the air depending upon the user's hair style.
[0008] The nozzle may be additionally provided with a vent which is
disposed outwardly of the ducts so as to direct an additional air
flow for expediting the hair drying.
[0009] Preferably, the casing includes an inner barrel which
defines therein the flow channel and also defines an outer flow
channel between the inner barrel the said casing. In this
connection, the ducts are configured to receive the forced air flow
through the flow channel within the inner barrel, while the vent is
configured to receive the forced air flow through the outer flow
channel. A heater is provided within one of the flow channel and
the outer flow channel, preferably within the flow channel
surrounded by the inner barrel so as to generate a cold air flow in
addition to the hot air flow simultaneously for minimizing the
damage caused by the hot air flow, yet assuring the rapid hair
drying.
[0010] Preferably, the vent is configured to have its opening
narrower towards the discharge end of the nozzle along the center
axis than at its opposite axial end. Thus, the nozzle can provide
an additional air flow of increased flow rate around the individual
air flows from the ducts for enhancing the effect of spreading out
the wetted hair strands. In this connection, the vent may be
configured to converge towards a point downstream of the discharge
end of the nozzle so as to increase the flow rate of the air
flowing out of the vent for effectively spreading out the wetted
hair strands in cooperation with the air flows directed from the
individual ducts through the localized strong air flow zones.
[0011] These and still other advantageous features of the present
invention will become more apparent from the following detailed
description of a preferred embodiment and its modifications when
taken in conjunction with the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a vertical section of a hair dryer in accordance
with a preferred embodiment of the present invention;
[0013] FIG. 2 is a horizontal section of the above hair dryer;
[0014] FIG. 3 is a perspective view of a nozzle utilized in the
above hair dryer;
[0015] FIG. 4 is a horizontal section of the above nozzle;
[0016] FIG. 5 is a side view of the above nozzle;
[0017] FIGS. 6 and 7 are graphs respectively illustrating flow
rates at various points of the nozzle;
[0018] FIG. 8 is a side view illustrating a modification of the
nozzle;
[0019] FIG. 9 is a perspective view illustrating another
modification of the nozzle; and
[0020] FIG. 10 is a perspective view illustrating a further
modification of the nozzle.
BEST MODE FOR CARRYING OUT THE INVENTION
[0021] Referring now to FIGS. 1 to 4, there is shown a hair dryer
in accordance with a preferred embodiment of the present invention.
The hair dryer includes a casing 10 elongated along an axis and a
grip 20 extending at an angle from the casing 10. The casing 10
accommodates therein a blower 30 in the form of an axial flow fan
driven by a motor 32 to generate an axially forced air flow
directed from an air inlet 12 at the rear end of the casing 10
towards a nozzle 60 provided at the front end of the casing 10. The
motor 32 is disposed downstream of the blower 30 and supported by a
rectifier 34 having baffles for rectification of the forced air
flow. As best shown in FIG. 2, the casing 10 includes a coaxial
inner barrel 40 which is disposed downstream of the blower and
upstream of the nozzle 60 to define therein a flow channel 42
leading to the nozzle and an outer flow channel 14 between the
barrel 40 and an outer shell of the casing 10. The outer flow
channel 14 receives the forced air flow through a port 42 at the
rear end of the barrel 40 to direct the forced air flow to the
nozzle 60. A heater 46 is disposed within the barrel 40 to heat the
air flow directed through the flow channel 44 for providing a hot
air flow, while it is disposed upstream of the port 42 so as to
direct a cold air flow through the outer flow channel 14. The grip
20 is provided with a switch 22 for actuating the blower 30 as well
as the heater 46.
[0022] Also accommodated with in the casing 10 is a mist generator
50 which, as shown in FIG. 1, is disposed outwardly of the inner
barrel 40 and adjacent to the front top end of the casing 10 for
discharging a mist of charged minute water particles out through an
outlet 15. The mist generator 50 has an emitter electrode 52 which
is configured to condense water from within a surrounding
atmosphere and to receive a high voltage from a high voltage
generator 54 for electrostatically atomizing the water into charged
minute water particles.
[0023] The nozzle 60 is disposed at one axial end of the casing 10
downstream of the flow channel 44 with its center axis aligned with
the axis of the casing 10, and has a discharge end at its front end
for discharging the hot air and the cold air. As best shown in
FIGS. 3 and 4, the nozzle 60 is shaped into a double tube composed
of a cylindrical outer tube 62 and an inner tube 63 coaxial with
the outer tube 62 and coupled thereto by means of circumferentially
spaced ribs 61. A vent 64 is defined between the outer tube 62 and
the inner tube 63 to communicate with the outer flow channel 14 at
its rear end for passing the cold air flow therefrom. The inner
tube 63 is shaped to communicate with the flow channel 44 at its
rear end for passing the hot air flow therefrom. The inner tube 63
has its interior space divided into two ducts 65 by a partition 66
which lies in a separation plane S extending radially about the
center axis X of the nozzle. As shown in FIG. 4, the inner tube 63
is tapered towards the discharge end such that the ducts 65 have
their openings narrower towards the discharge end than at its rear
end. Also, the outer tube 62 is tapered towards the discharge end
to converge the vent 64 towards a point downstream of the discharge
end.
[0024] The partition 66 is elongated over the full diameter of the
inner tube 63 and has a horizontal cross-section, i.e., cross
section perpendicular to its length, which converges to a closed
sharp edge 69 at its rear axis end. The inner tube 63 has a
circular opening at its rear end concentric with the axis of the
barrel 40 so that the hot air flow from the barrel 40 can be guided
uniformly into the inner tube 63 and is diverged at the sharp edge
69 to flow into the individual ducts 65 without causing turbulence.
The partition 66 has an increased width W at its front open end,
and is formed on its opposite sides at its front end portion with
flat faces 68 which defines respectively inner side faces of the
ducts 65 adjacent to the discharge end. The front open end of the
partition 66 is fitted with a cap 67 having a rounded projection.
Since the ducts 65 are separated from each other at its discharge
end by the width W of the partition 66, the hot air flows
discharged from ducts respectively through local strong flow zones
downstream of the discharge end, while leaving a weak air flow zone
between the strong flow zones. That is, the individual ducts 65
form the local strong flow zones downstream of the discharge end
for directing the hot air flow, while the partition 66 forms the
weak flow zone separating the local strong flow zone. The strong
flow zones thus formed locally around the weak flow zone to create
a waved air flow of varying flow rate, which is responsible for
spreading out the wetted hair strands to increase chance of
exposing the hair to the hot air and therefore expedite the hair
drying. The vent 64 surrounding the ducts 65 is held in
communication with the outer flow channel 14 to discharge the cold
air flow fed from within the casing 10 in such a manner to form a
cold air flow envelop around the localized strong flow zones,
promoting to spread out the wetted hair strands in addition to
relieving heat damage from applying to the hair. In this
connection, with the provision of the presence of the flat faces 68
on the inner side of each duct adjacent the discharge end, it is
possible to avoid interference between the individual air flows
immediately discharged from the ducts for realizing efficient air
flow through the strong flow zone in combination with the tapered
structure of the ducts 65. Each of the ducts 65 defined by the
inner side wall and an arcuate outer side wall is elongated to have
a length along the length of the partition and a reduced width
perpendicular to the length of the partition. Thus, the nozzle 60
is given directional selectivity for providing an optimum hair
drying effect such that the can orient the nozzle in relation to
the user's hair style for effective hair drying.
[0025] Referring to FIGS. 5 to 7, there is shown an optimum
relationship among several dimensions of the nozzle 60, i.e., (a),
(b), (c) along a line P passing through the center axis X
perpendicular to the separation plane S, (e) and (d) along a line Q
extending in parallel with the separation plane S and passing
through a maximum length of the duct 65, and (f) along a line R
extending in parallel with the separation plane S and passing
through a width center of the vent 64 on the line P. Dimension (a)
is a distance from the center axis to the flat face 68 of the duct
65, dimension (b) is a distance from the flat face 68 to the outer
side of the duct 65, i.e. a maximum width of the duct, and
dimension (c) is a distance from the outer side of the duct to the
outer side of the vent 64. Dimension (d) is a distance from line P
to interior face of the duct 65 along line Q, dimension (e) is a
distance from the outer side of the vent 64 to the interior face of
the duct along line Q, and dimension (f) is a distance from line P
to the interior face of the vent 64 along line R.
[0026] FIG. 6 illustrates a schematic graph of a flow rate
distribution along line P in relation to dimensions (a), (b) and
(c) along line P with the dimensions shown in abscissa. As is seen
in the graph, an optimum relation is founded to be a:b:c=1:3:2.
Dimension (a) is preferred to be 3 mm to 5 mm for accelerating the
hair drying without causing heat and unpleasant feeling to a user,
and most preferably to be 4 mm. Accordingly, the width (W) of the
partition 66 (W=2a) is preferred to be 6 mm to 10 mm, and most
preferably 8 mm for creating the strong flow zones sufficient to
spread out the wetted hair strands.
[0027] FIG. 7 illustrates a schematic graph of flow rate
distributions along lines P, Q, and R in relation to dimensions
(d), (e), (f) with the dimensions shown in coordinates. An optimum
relation for effectively providing the strong flow zones is derived
from the graph to be d:e:f=8:1:4. Dimension (d) is selected to be
15 to 17 mm with associated dimensions (e) and (f) satisfying the
above relation.
[0028] Although not illustrated in the figures, the vent 64 may be
configured to have its opening narrower towards the discharge end
of the nozzle along the center axis than at its rear axial end, in
order to increase the flow rate of the air flow from the vent 64
for enhanced effect of spreading out the wetted hair strands.
[0029] FIG. 8 illustrates an alternative nozzle in accordance with
a modification of the above embodiment which is basically similar
to the above embodiment except that a pair of vents 64 is formed
laterally outwardly of the ducts 65 generally in parallel
therewith. The other configurations and functions are identical to
the above embodiment, and therefore no duplicate explanation is
made herein. Like parts are designated by like reference
numerals.
[0030] FIG. 9 illustrates another modification of the nozzle which
is similar to the above embodiment but is dispensed with the vent.
Like parts are designated with like reference numerals without
reciting duplicate explanation. In this modification, the nozzle is
shaped to be bifurcated into two separate tubes which are separated
by a partition 66 but have its rear end merged into a circular
opening for connection with the front end of the casing.
[0031] FIG. 10 illustrates a further modification of the nozzle
which is similar to the above embodiment except that more than two
ducts are formed symmetrically about the center axis X. Like parts
are designated by like reference numerals. The nozzle 60 is divided
into five ducts 65 which have their respective rear ends merged
into a single circular opening for connection with the front end of
the casing. The ducts are each configured to have a triangular
shaped cross section smaller towards the discharge end than at the
rear end, and are circumferentially spaced about the center axis X
as being divided from each other by a distance of W by means of
separation planes S1 to S5 each extending radially about the center
axis X of the nozzle. In this instance, the inner side wall of each
duct is cooperative with the opposed inner side wall of the
adjacent duct to constitute a partition having the width of W. With
this arrangement, more than two strong flow zones are formed
downstream of the individual ducts as being circumferentially
spaced apart by the weak flow zones so as to generate the air flow
of varying rate effective for spreading out the wefted hair
strands.
[0032] Although the present invention has been described with
specific reference to the above embodiments and modifications, it
should not be interpreted to such embodiment and modifications and
encompass a combination of the individual features derived from the
embodiment and modifications.
* * * * *