WO1979000374A1

WO1979000374A1 - Hand-held electric hair dryer

Info

Publication number: WO1979000374A1
Application number: PCT/US1978/000212
Authority: WO
Inventors: S Godel
Original assignee: Remington Products
Priority date: 1977-12-12
Filing date: 1978-12-08
Publication date: 1979-06-28
Also published as: DE2853197A1; EP0008293A1

Abstract

A hand-held electric hair dryer which comprises a handle supporting a wing-shaped hollow casing having a motor driven axial fan carried by the rear wall of the casing. An air inlet is provided in the rear wall of the casing, whereby an airstream generated by the fan enters the casing for flow therethrough. The airstream exits through an elongated air discharge opening formed in an arcuate-shaped front wall of the casing. An interior portion of the rear wall of the casing adjacent the air inlet is flat and extends on a plane substantially normal to the axis of rotation of the fan, and a portion of the fan projects beyond the flat portion in the direction of the discharge opening. The shape and location of the interior portion of the rear wall adjacent the air inlet and the projection of a portion of the fan beyond the flat portion causes the airstream generated by the fan not only to move forward toward the discharge opening but also causes a portion of the airstream to move along the rear wall of the casing as well as toward the front wall. In this manner, air exits from the discharge opening to present a substantially equal or uniform velocity gradient across the discharge outlet. A heater is provided within the casing between the fan and the discharge opening to heat the air prior to its leaving the discharge opening.

Description

A HAND-HELD ELECTRIC HAIR DRYER

BACKGROUND OF THE INVENTION

This invention relates to improvements in portable electric hair drying appliances and more particularly to hair dryers that may be hand-held for ready manipulation about the head of a user to dry the hair.

Portable hand-held hair drying appliances are¹well- known and there are generally considered to be three basic types in widespread use. These basic types of hand-held hair dryers may be characterized as firstly, a pistol-type which utilizes a centrifugal fan, wherein the handle por¬ tion depends from the main body and is arranged perpen¬ dicular to a hot air exhaust outlet such as is disclosed in U.S. Patent No. 4,019,260. A second hair dryer is the circular-type which includes an axial fan wherein the handle portion is arranged in line with the hot air ex¬ haust outlet such as is disclosed in U.S. Patent No. 4,039,774. A third type is the hatchet type dryer which incorporates a cross flow fan, wherein the handle portion is in line with the main body and the hot air ex- haust outlet is arranged at a right angle with respect to the main body and handle portion, such as is disclosed in U.S. Design Patent No. 228,817. The foregoing hair dryers may be more aptly viewed as styling dryers inasmuch as they are almost invariably used in conjunction with combing or brushing of the hair to build up and set or style the hair. As such, these styling dryers have gained wide¬ spread acceptance.

Users are particularly interested in reducing the time required to dry the hair. In the design of hand-held dryers, the designer of the product will work with both the airflow and temperature of the air to optimize the design in terms of performance, keeping in mind at all times, cost considerations. A preferred arrangement for a hand-held hair dryer is to have an elongated discharge opening to project air over a larger portion of the head than the pistol type or circular type dryer. However, typicall a cross-flow fan has been used with an elongated discha outlet but such dryers have a number of disadvantages, among which is the cost of the fan.

Accordingly, it is an object of the present inven tion to provide a novel portable hand-held electric hai dryer.

Another object is to provide a novel hair dryer which has an elongated discharge opening in a hollow ca which carries a motor driven fan, and means are provide to effect a uniform distribution of air at the discharg opening with a substantially equal velocity flow gradie

A further object is to provide a novel hair dryer which includes an axial fan for generating an airstream be discharged through an elongated discharge opening.

A still further object is to provide a novel and proved hair dryer which includes a heater assembly whic covers substantially less than the length of an elongat discharge opening.

SUMMARY OF THE INVENTION

The present invention comprehends a novel portabl hair dryer having a hollow casing which includes an elo gated discharge opening in the front wall of the casing and an axial fan which generates an airstream within th casing for exit through the discharge opening. The axi fan is so arranged with respect to an interior portion the rear wall of the casing as to cause a portion of th generated airstream to move along the rear wall as well toward the discharge opening to provide for a uniform d tribution of discharged air from the casing to effect a substantially equal velocity flow gradient along said d charge opening. A handle is provided at an angle to th casing to permit a user to comfortably hold and manipul the dryer with respect to the hair. A heater assembly disposed in the casing in the path of flow of the air- airstrea to heat the air prior to discharge from the casing. The heater is elliptically-shaped in transverse cross section and extends substantially less than the en- tire length of the discharge opening.

The hair dryer of the present invention is designed and constructed for mass production and incorporates readily assembled components and sub-assemblies to thereby reduce costs and to provide for ease of manufacture. These and other objects and features of this inven¬ tion will become apparent with reference to the following specification and to the drawings.

DESCRIPTION OF THE DRAWINGS In the drawings: FIG. 1 is a perspective view of the novel hair dryer of the present invention;

FIG. 2 is a fragmentary front elevational view of the hair dryer of FIG. 1 with some vanes removed to show the interior of the hair dryer; FIG. 3 is a fragmentary side elevational view taken along lines 3-3 of FIG. 2;

FIG. 4 is a sectional view taken along line 4-4 of FIG. 2;

FIG. 5 is a sectional and fragmentary view taken along lines 5-5 of FIG. 4;

FIG. 6 is a schematic representation showing an un¬ desirable velocity flow gradient of the airstream taken along the discharge opening of the hair dryer with the fan in a non-preferred position; FIG. 7 is a schematic representation of the present invention showing a desirable velocity flow gradient of the airstream taken along the discharge opening of the hair dryer with the fan in the preferred position. DETAILED DESCRIPTION

Referring now to the drawings and more particularly to FIG. 1 a novel hair dryer is generally indicated by re erence 10. Hair dryer 10 comprises a hollow elongated ca sing 12 carried by a transversely extended handle 14 whic is shaped for easy and comfortable manipulation by a user The casing is wing-shaped and has a front wall 16, a pair of end walls 17 and 18, bottom and top horizontally dis¬ posed walls 20 and 22 respectively, and a rear wall 24, t form a compartment 26. Front wall 16 is completely open between end walls 17 and 18 to form a discharge opening o outlet 28. In effect, the extent of discharge opening 28 occupies the same area as rear wall 24. A detachable gri 30 is provided in the discharge opening and includes spac vanes 31 to prevent entry of fingers of a user and the li from entering casing 12. Projections 32 extend from bott wall 20, and grill 30 is secured at such projections by screws 34 which extend through tabs 35 formed in the gril For ease of manufacture and assembly, casing 12 is made i two parts, an upper part 12A and a lower part 12B (FIG. 2) which set at a parting line 36 as best shown in FIG. 1. Upper and lower casings parts 12A and 12B are secured to¬ gether at two places in compartment 26 by threaded member 38 received in bosses 40 molded to upper and lower casing parts 12A and 12B.

Bottom and top walls 20 and 22 (FIG. 3) diverge fro front wall 16 to meet and merge with rear wall 24 (FIG. 1) As best seen in FIGS. 1 and 2 the bottom and top walls ar curved or contoured adjacent rear wall 24 to form an air inlet 41 for casing 12 (FIGS. 3, 4). Air inlet 41 accom¬ modates a cylindrical-shaped tube or conduit 42 having an outlet orifice 43 and a pair of diametrically opposed and perpendicularly extending ears 44 (FIG. 2, 4) . The outer surface edges 45 of ears 44 fit snugly against rear wall 24, whereby said ears 44 become in effect an interior por¬ tion of the rear wall adjacent air inlet 41. Conduit 42 has a plurality of spaced ribs or spokes 46 molded therei

and a central bearing portion 48 for securing thereto, by way of screws 50, an electric motor 52 which has mounted thereon an axial fan 53. Fan 53 has blades 54 which are provided with a leading edge 54A and a trailing edge 54B. Electric motor 52 has a pair of motor terminals 55 for con¬ nection by wires (not shown) to an on-off electric switch (not shown) operable by a switch actuator 56 (FIG. 1) in handle 14. A power cord 58 is partly shown and protrudes from the base of handle 14 for connection to a power source (not shown) to thereby cause energization of motor 52 upon actuation of the switch to an on position.

Motor 52 is disposed within and enclosed by a pro¬ tecting cap portion 60 which has a plurality of radially spaced vanes or ribs 62. Operation of fan 53 causes air to flow through vanes 62 into air inlet 41 and past spokes 46 into casing 12. Cap 60 is provided with recesses 61 having seating surfaces 64 (FIG. 3) which are secured by a pair of threaded members 66 extending through projec¬ tions 68 of rear wall 24 and to tabs 70 formed in spokes 46 of conduit 42. In this manner, cap 60 and conduit 42 are securely held and fastened to upper and lower casing parts 12A and 12B.

A heater assembly 72 is provided in casing 12 be¬ tween discharge outlet 28 and air inlet 41. Heater assembly 72 is substantially frustoconical, and in trans¬ verse cross section is shown to be elliptical in shape and extends substantially less than the entire length of discharge opening 28. Heater assembly 72 includes an insulated plate member 74 which extends along the major axis of the assembly and a transversely extending plate member 76 is arranged normal to the plate 74 and along the minor axis of the ellipse. As better seen in FIG. 4, plate 74 is enlarged at its base 74A, adjacent to fan 53, and has a shorter edge 74B adjacent front wall 16. Plate member 76 is similarly shaped in that its enlarged base 76A and shorter edge 76B are adjacent fan 53 and front wall 16, respectively. The side edges of plate members 74 and 76 are notched as at 82 to receive a coiled electrical re¬ sistance element 83 which is helically wound on plate members 74 and 76. A pair of flow directing plate mem- bers 84 and 86 are criss-crossed at the intersection of plate members 74 and 76 to occupy the quadrants (as best seen in FIG. 2) formed by the plate members 74 and 76. Plate members 84 and 86 are similarly provided with notc portions along their edges to also receive and support t coiled resistance element.

Two L-shaped brackets 88 are provided at the base tion of plate 74 and one leg 88A (FIG. 5) of each bracke is secured to plate 74 by a rivet 90 and another leg 88B each bracket 88 is secured to ear 44 by a threaded-nut assembly 92. In this manner, heater 72 is detachably se cured to ears 44. One of the brackets 88 also serves to provide an electrical connection between an end 83A of r sistance element 83 and the end of an insulated wire 94 (partly shown) which has its other end (not shown) conne ted in handle 14 to power cord 58. Another end of resis ance element 83 is connected by a terminal 95 to insulat wire 96 (partly shown) on shorter edge 74B of plate 74.

As seen more particularly in FIGS. 3 and 4 the tra ing edges 54B of blades 54 of fan 53 project beyond the plane of ears 44 in the direction of discharge opening 2

The projection of a portion of fan 53 and the shape and position of ears 44 are an important feature of the pres invention which may be more completely understood by an explanation in reference to the schematic representation in FIGS. 6 and 7.

First, it should be explained that in the operatio of an axial fan in a conduit, the fan blades cause the a to be thrown out against the inner periphery of the cond where the air increases in pressure as it moves from the leading edge of the blade to the trailing edge. The air reaches its maximum pressure as it leaves the trailing edge of the blade to cause swirling and turbulence of air in the area. The turbulent air in effect dissipates some of the energy of the air issuing from the blades, and further acts to constrict the stream of pressurized air to what might be generally seen, in transverse cross- section, as an axially moving cylinder of air. The swirl¬ ing and turbulent air also tends to reduce the diameter of the axially moving cylinder of air to less than the blade diameter of the fan, and the main thrust of the cylinder of air due to the pitch of the blades is in an axial direction or concentric to the axis of rotation of the fan. The effect of this in respect to a velocity flow gradient of the airstream exiting the discharge opening may be seen in FIG. 6.

In FIG. 6 fan 53 is shown, contrary to the present invention, withdrawn into conduit 42 and a line 100 repre¬ sents the velocity gradient of the airstream leaving dis¬ charge outlet 28. The lines A and B represent the magni- tude of velocity of the air at opening 28, but they are not to be taken in any strict quantitative sense because they are merely for illustration. Since it is desired to have a uniform distribution of air across the length of the dis¬ charge outlet, hair dryer devices which would produce this uneven velocity gradient of air flow are undesirable.

FIG. 7 is a schematic representation of the present invention showing a desirable arrangement of fan 53 which causes a uniform distribution of air at discharge opening 28, wherein the velocity gradient of the discharge air is substantially uniform or equal across the opening. It is believed that this effect is obtained because of the pro¬ jection of the trailing edges 54B of blades 54 beyond out¬ let orifices 43 of conduit 42. As the compressed air leaves conduit 42, the projecting edges 54B of blades 54 exert a centrifugal or radial force on the column of air

-8- pr airstream leaving outlet orifice 43. A portion of th airstream is thus directed perpendicular, or normal to the axial direction of the moving cylinder of air, and swirling or turbulence of air adjacent the periphery of conduit 42 is reduced to some extent. By providing ears 44 with flat surfaces on a plane normal to the axis of rotation of the fan and having trailing edges 54B extend ing beyond the flat surfaces in the direction of the dis charge opening, that portion of the airstream that is radially directed moves along the surface of ears 44 and the inner surface of rear vail 24 towards end walls 17 a 18. A forward movement is imparted to the radially dire ted air by the diverging shape of the inner surface of rear wall 24 as it extends from ears 44 to the end walls 17 and 18 resulting in a substantially axial movement of the air throughout the casing toward discharge opening 2 Thus, the distrubution of air as it leaves outlet 28 is provided with a substantially equal velocity gradient represented by line 102 across the length of the outlet. Differing distrubutions of axial and radial airflow can had at exhaust orifice 43 of conduit 42 by changing the amount of extension of blade edges 54B outwardly of orif 43 in order to vary the velocity gradient of the exiting air across discharge outlet 28. The arrows A and B repr senting the velocity flow of the airstream as in FIG. 6, are used for purposes of illustration and explanation on and are not to be taken in any absolute quantitative sen

The column of air issuing from conduit 42 does not only have an axial thrust to it. The air column is also cyclonic or swirling in nature and as it flows through t heater assembly it is interrupted by plate members 74 an 76. If it were not for the inclusion of plate members 8 and 86 in the heater assembly, plate members 74 and 76 would cause areas of reduced air flow, or what are terme as air shadow areas, on portions of resistance element 8 These portions would tend to produce a red glow, or hot

(

^ spot on the element 83 and thereby cause undesirable lo¬ calized heating of the adjacent walls of casing 12. The addition of plate members 84 and 86 cause a redirection of the airstream passing through the heater assembly to reduce the incidence of hot spots on the resistance element.

Further to reducing undesirable localized heating of the walls of casing 12 an elongated aperture 104, FIGS. 1 and 3, is provided in top wall 22 of casing 12 adjacent tube 42. During operation of hair dryer 10 relatively cool air is drawn into compartment 26 through elongated aperture 104 by the heated airstream moving along the in¬ ner surface of top wall 22 immediately adjacent heater 72. The cooler incoming air mixes with and moderates the heated airstream along the inner surface of top wall 22 to form a thermal barrier. The thermal barrier prevents localized heating of the top wall immediately adjacent the uppermost portions of the resistance element.

Aperture 104 also provides means for faster cooling of the hair dryer immediately after shut-off by allowing residual heat in the hair dryer to escape through the aperture.

A barrier member 106 extending from the outlet end of tube 42 and beneath aperture 104 is provided to prevent direct contact of external foreign objects with portions of resistance element 83 exposed by aperture 104.

In the use of hair dryer 10, front wall 16 may often be positioned with respect to the user's head in such a manner that the end portions of outlet 28 will extend beyond the head and exiting air will not strike the user's head. At other times, the front wall may be in a position where the middle of the outlet 28 is closer to the head than are the end portions of the outlet. This may exist when the front wall 16 has a portion above the top of the head and a portion along the side of the head. In this jcase air from the outlet ends may or may not strike the head or when it reaches the head the temperature of the air may be less than that issuing from the middle of out let 28 and striking the head. The present invention avo these possibilities by making front wall 16 arcuate-shap as well shown in FIGS. 1 and 4. It will be apparent fro the foregoing description and drawings that the novel hand-held hair dryer includes the advantage among other advantages, of providing an efficient hair dryer for rapidly drying the hair of the user. The structure of t hair dryer permits the utilization of a less expensive axial fan which, in combination, effects a uniform distr bution and substantially equal velocity gradient of air through an elongated discharge outlet to cover more area of the user's head to enhance the drying time. Further¬ more, the several parts and components of the novel hand held hair dryer lend themselves readily to mass producti techniques.

While there has been described one embodiment of t invention, it will be apparent to those skilled in the a that variations may be made without departing from the spirit and scope of the appendant claims.

OMP

Claims

What is Claimed is:

1. A hand-held electric hair dryer comprising: a. a hollow casing having a rear wall and a dis¬ charge opening spaced from and opposite said rear wall, the extent of said discharge opening occupying substan¬ tially the same area as said rear wall; b. a handle for supporting the casing; c. an air inlet for said casing formed in a cen¬ tral portion of said rear wall opposite said discharge opening; d. a cylindrical conduit having a longitudinal axis arranged in said casing in axial alignment with said air inlet, one end of said conduit forming an outlet orifice spaced from said air inlet in the direction of the discharge opening; e. a motor driven axial fan supported by said casing adjacent to and in axial alignment with said air inlet, said axial fan having a plurality of blades arranged for rotation in said conduit with portions of said blades ex- tending outwardly of and in a predetermined spaced relation¬ ship to said outlet orifice in the direction of said dis¬ charge opening, said axial fan being operable for gener¬ ating an airstream constrained to flow through said conduit and outwardly of the discharge opening; f. heating means disposed on said casing between said outlet orifice and said discharge opening for heating the airstream prior to exiting the discharge opening, and g. surface means on said rear wall extending from said outlet orifice on a plane normal to the axis of said conduit and cooperatively associated with said predetermined spaced relationship of said extending portions of the blades for providing the airstream exiting said discharge opening with a substantially equal velocity gradient across the extent of said discharge opening.

2. The hair dryer of Claim 1 wherein said sur¬ face means include an interior portion of said rear wal joined with said conduit at said outlet orifice in a plane normal to the axis of rotation of said blades.

3. The hair dryer of Claim 2 wherein said condui is formed with diametrically opposed flat ears dispose normal to the axis of said conduit.

4. The hair dryer of Claim 3 wherein said rear wall has an elongated shape and said casing is provide with a pair of spaced end walls and a front wall space from said rear wall by said end walls and said dischar opening is rectangular-shaped extending longitudinally in the direction of said end walls.

5. The hair dryer of Claim 4 wherein said disch opening extends from one end wall to the other end wall and is substantially greater than the diameter of said conduit.

6. The hair dryer of Claim 5 wherein said heater means is arranged in said casing in alignment with said conduit, said heater means being generally elliptical i transverse cross section with the major axis of said heater means extending longitudinally of said casing fo a distance substantially less than the entire length of said discharge opening.

7. The hair dryer of Claim 6 wherein said heater means includes an electrical resistance element helical wound about a heater support, said support including a first plate extending along the major axis and toward t end walls of said casing,, and a second plate lying tran versely of said first plate and extending along the min axis of the heater means toward the top and bottom of said casing.

8. The hair dryer of Claim 7 wherein said first plate and said second plate becomes smaller in dimensio as they extend from the rear wall to the front wall of said casing.

OM 1P

9. The hair dryer of Claim 8 wherein air di¬ recting means are provided in said heater support for re¬ directing the airstream through the heater means as the air flows to the discharge outlet to minimize excessive localized heating of said resistance element and adjacent casing walls.

10. The hair dryer of Claim 5 wherein the front wall of said casing is arcuate shaped and said discharge opening is formed coextensive with said front wall with the middle portion of said discharge- opening being closer to said air inlet in the direction of airflow and the end portion of said discharge opening being further away from said air inlet in the same direction.