US3303325A

US3303325A - Electric hair dryer having combined motor switch and thermostatic heater switch control means

Info

Publication number: US3303325A
Application number: US345192A
Authority: US
Inventors: Frederick M Hubrich
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1964-02-17
Filing date: 1964-02-17
Publication date: 1967-02-07
Anticipated expiration: 1984-02-07

Description

Feb. 7, 1967 F M. HUBRICH 3,303,325

ELECTRIC'HAIR DRYEh HAVING COMBINED MOTOR SWITCH AND THERMOSTATIC HEATER SWITCH CONTROL MEANS Filed Feb 17, 1964 2 Sheets-Sheet 1 FIG.

Feb.- 7, 1967 F M. HUBRICH 3,303,325

ELECTRIC HAIR DRYER HAVING COMBINED MOTOR SWITCH AND THERMOSTATIC HEATER SWITCH CONTROL MEANS Filed Feb. 17, 1964 2 Sheets-Sheet 2 FIG. 2

INVENTOR. FREDERICK M. HUBRICH BY -5M ATTORNEYS United States Patent 3,303,325 ELECTRIC HAIR DRYER HAVING COMBINED MOTOR SWITCH AND THERMOSTATIC HEATER SWITCH CONTROL MEANS Frederick M. Hubrich, Farmington, Conn., assignor, by mesne assignments, to General Electric Company, Bridgeport, C0nn., a corporation of New York Filed Feb. 17, 1964, Ser. No. 345,192 2 Claims. (Cl. 219364) This invention relates to hair dryers, including dryers which have incorporated therein controlled electrical means for heating the air.

In electric hair dryers, it is desirable to maintain the discharge air at constant temperatures to promote even drying and to prevent injury to the hair and scalp. In many hair dryers, a thermostatic switch is provided in the air discharge outlet to control the heater operation. In a known arrangement, the thermostatic switch may be combined with the blower motor switch so that the heater can be energized only when the blower is on. When such arrangements are used in hair dryers of the hand-held type, it is incumbent upon manufacturers to make the controls as light and compact as possible so as not to add to the weight or bulk of the hair dryer. It is also desirable to produce a control arrangement which is simple in design and operation and relatively inexpensive to manufacture. The prior art devices have not proven to be fully effective in producing all these desirable features.

It is, therefore, an object of this invention to provide a simplified, combined thermostatic heater switch and blower motor switch arrangement for a hair dryer.

It is another object of this invention to provide a combined thermostatic heater switch and blower motor switch arrangement for a hair dryer which is less expensive and more compact than comparable prior art devices.

In accordance with my invention in one form thereof, I provide a hair dryer including a blower motor switch and a bimetal-operated thermostatic heater switch in the air discharge outlet. The controller for the switches comprises a rotatable member including a disc portion having a spiral cam groove therein and having an outer peripheral cam surface engaging a motor switch contact arm. An abutment member is mounted on the heater switch bimetal arm and includes a portion received in the cam groove. Rotation of the rotatable'member results in movement of the motor switch contact arm to open and close the motor switch and, also, positions the abutment member along the heater switch bimetal arm to, regulate the opening temperature of the heater switch. The rotatable member is so designed that rotation thereof causes the motor switch to close before the heater switch is closed.

ther and more detailed objects of the invention will be apparent from the embodiments thereof disclosed in detail in connection with the accompanying drawings.

In those drawings:

FIGURE 1 is a top plan view of one assembly in accordance with this invention, with a portion of the housing omitted;

FIGURE 2 is a cross sectional view taken on the line 22 of FIGURE 1;

FIGURE 3 is an enlarged detail view taken on the line 3-3 of FIGURE 1, illustrating the air outlet passage and showing the thermostat control device;

3,303,325 Patented Feb. 7, 1967 FIGURE 4 is a cross sectional view taken on the line 4-4 of FIGURE 3;

FIGURE 5 is a cross sectional view taken on the line 5-5 of FIGURE 4; and

FIGURE 6 is a cross-sectional view of another form of the device taken on the line corresponding to the line 22 of FIGURE 1.

Referring to FIGURES 1 and 2 the assembly includes an outer container iii of any suitable configuration which might, for example, be a part of the carrying case for the device. It may be made of any suitable material, including, for example, a molded plastic. This casing includes in the form illustrated a re-entrant annular Wall 12 forming a part of the casing for the fan rotor and electric drive motor illustrated. A cover 14 of similar material and of matching configuration is held on the upper end of the wall 12 by any suitable form of fastening devices, such as those illustrated at 16 in FIGURE 1. The casing cover 14 is provided with a large central opening defined by an annular lip 14a projecting int-o the space or blower chamber 18 formed by the casing 1214. The casing 12-14 is provided with a tangential extension 12a characteristic of a centrifugal type of blower housing. This tangential extension terminates in an air discharge port 20 to which the flexible hose commonly used with such devices can be detachably secured. The tangential extension 12a is formed in part by an integral attachment to the wall 12, see FIG. 3, and the upper part of the discharge passage is formed by a removable cover 26a, which in the form illustrated will be made of an insulating material,

Within the space 18 is the blower arrangement comprising a rotatable blower wheel or fan rotor 22, which is illustrated as of cup-shaped form of circular cross section. The rotor 22 has a plurality of internally projecting radially extending fan blades 22a. These blades, for example, can be struck out from the rim of the fan rotor leaving openings through the blades from which the air may exit. Alternatively, the blades could be fastened in any suitable manner and the rim of the cup provided with apertures with the same effect. The fan rotor 22 is provided with a bearing fixture 24 secured to it. The fixture is journaled at its lower end in a boss 10a formed integrally with the container 10 and at its upper end by means of a pin journaled in the lower bearing assembly 36 of the electric drive motor 30. The fixture 24 is provided with a gear 24a.

The fan rotor and motor dished cap 26 which encloses lip 14a and is secured to the fastening devices 28.

The electric motor 30 which may be of any type suited to the purpose as, for example, a shaded pole motor, is secured to the underside of the cap 26 by means of the posts 49 and the nuts 42. This motor includes a field energizing winding 32 which projects through an opening in the cap 26 and lies in the path of a portion of the intake air by being positioned adjacent to the inlet opening 26b and extending down into the passage formed by the lip 14a. The upper bearing assembly for the motor is shown at 34 and the lower bearing assembly at 36. The motor shaft projects below the bearing 35 and is provided with a pinion 38 of larger diameter than and meshing with the gear 24a.

Positioned within the space 18 and displaced approximately circumferentially with respect to the cap casing is completed by a the passage formed by the cover 14 by means of the opening 26b are a pair of parallel metal fins 46 between which and around which the air may pass. These fins are secured to the under surface of the cap 26 in any suitable manner and are provided with a series of blades 46a struck inwardly from the fins into the passage between the fins. Supported by the fins in any suitable manner is an electric resistance assembly 44. The cap 26 is provided with a series of air inlet openings 26c, as clearly shown in FIG. 1.

Journaled in a depending boss in the cover 26a is a rotatable stem 18 which projects above the cover and has secured thereto a control knob 56. The lower end of the stem is expanded into a disk 48a having a cam grove 48b on its under surface. As illustrated in FIG. 4, this cam groove is concentric for about 90 and then takes a spiral shape to its other terminus. Secured on a shoulder forming part of the cap cover 26a by mean of the machine screws 52 is a metal switch arm 54 having a contact 54a at its free end. A circuit 'wire 56 connects I the screw 52 to one terminal of the heater 44. A positioning screw 58 extends through the cover 26a so as to bear upon the arm '54 and it is adjacent its zero position. At 60 is a machine screw engaging another shoulder on the cap 26a and provided to secure in place a bimetal switch arm 62 having a contact 62a cooperating with the contact 54a. The screw 6% serves also to mount a cantilever spring arm 64, which cooperates with a notch or cam surface formed in the disk 48a, see FIG. 4. Mounted on another shoulder formed on the cover 26a by means of a machine screw is a contact as positioned to cooperate with the cantilever spring arm 64. A circuit wire 70 connects the current source to this contact and circuit wire 71 is connected to one terminal of the motor 30. Slidably mounted on the bimetal switch arm 62 is an abutment member 66 having an end which cooperates, as shown in FIG. 5, with the cam groove 48b.

The modification illustrated'in FIG. 6 is generally similar to the first form of the device with the exception of the distinguishing features now to be set forth. Assuming that the assembly of FIG. 6 is to generate the same volumetric air flow as the design of the preceding fig-- ures, the fan rotor 22 is made proportionately larger to compensate for the fact that it rotates more slowly. This results from the fact that the fan rotor 22 is mounted directly on the end of the motor shaft and concentric therewith by means of fixture 24. It will be seen in this case that the gear train of the preceding arrangement has been omitted with the result that the fan rotor runs the motor speed. It is for this reason that the fan rotor is made larger. The vertical compactness of the assembly of FIG. 6 is increased by the fact that the fan rotor is mounted directly on the motor shaft and hence the motor is more deeply telescoped with the fan rotor than in the preceding case. I

In the operation of the device the circuit for the motor 30 (not shown) is controlled by the switch formed through cantilever arm 64 and contact 68 incorporated with the thermostatic control (see FIG. 4). The motor is energized before current can be supplied to the heater. With the motor 30 energiezd the fan rotor 22 will revolve, drawing air into the casing 12-14-26 through the

inlet openings

26b and 260. The portion of the air entering through 26b will simultaneously serve to cool the motor and particularly its field winding 32 and use that heat to warm the air. As is clear from FIG. 1, electric resistance heater 44 is in the area adjacent the outlet 20, so that the fan rotor will cause the air to flow around this heater further raising its temperature. The fins 464661 are positioned so that the air flows around them and is directed and caused to flow around the heater 44 effecting an eificient transfer of heat'to the air.

The temperature of the air can be roughly controlled by means of the knob In the off position of the knob the cantilever contact 64 is in the position shown in FIG. 4- .so that the circuit to the heater is open. When 4 the knob 50 is turned from the off position to the low" position the hump on the switch lever 64 slides out of the notch on the disk 48a, causing the end of the lever 64 to engage the contact '68. This completes the circuit from the current source through the wire 70, contact 68, spring finger 64, bimetal element 62-,

contacts

62a and 54a, conducting arm 54, through the wire 56 to one terminal of the heater 44. The other terminal is connected in an obvious manner to the current source. Since the cam groove 48b is concentric for the first quarter turn the abutment member 66, see FIG. 5, does not move along the bimetal element 62. At the end of this movement the pointer of the knob 50 is in the low position. At this time the abutment 66 is as far to the right, FIG. 5, as it can be positioned. Thus, the heater 44 is energized and supplies heat to the air flow through the outlet 20. Should the air rise above a temperature predetermined by this setting, the projecting end of the bimetal element 62 will flex upwardly and break the circuit to the heater. When the knob 50 is turned further, say to the indicia position Med. the abutment 66 will be moved to the left, FIG. 5, a distance corresponding to the increasing radius of the spiral portion of the groove 48b. Thus, the air coming from the heater must get hotter before it can cause the shortened end of the bimetal element 62 to break the circuit at the contacts 54a-62a. As is obvious, if the knob 50 is moved further and further in the same direction the abutment 66 moves more and more to the left, FIG. 5, requiring a still higher temperature for the exiting air to break the circuit. To shut the heater off the knob 50 is rotated back to the off position.

From the above disclosure it will be apparent to those skilled in the art that the embodiments illustrated herein attain the objectives set out above. It will be equally apparent that some changes in the details of construction of the embodiments used for illustrative purposes will be readily obvious to those skilled in the art while not departing from the novel subject matter herein disclosed.

What is claimed:

1. An electrically-powered blower for a hair dryer comprising:

7 (a) a casing defining a centrifugal blower chamber and having air inlets and an air discharge port;

(b) a rotatable blower wheel within said blower chamber;

(c) an electric drive motor within said casing connected to rotate said blower wheel;

(d) an electric heater positioned within said casing and adjacent said discharge port;

(e) a mot-orswitch comprising a first stationary contact and a movable spring armlincluding a contact thereon;

(f) a thermostatic heater switch adjacent said heater comprising a second stationary contact and a flexible bimetal armincluding a contact thereon; and

' g) combined motor switch and thermostatic heater switch control means comprising a rotatable member including at one end thereof a disc portion having a spiral cam groovetherein and having an outer peripheral cam surface engaging said spring arm, and an abutment member slidably mounted on said bimetal arm and including a portion received in said cam groove, such that selective rotation of said rotatable member moves said spring arm contact into and out of engagement with said first tationary contact and positions said abutment along said bimetal arm.

2. The electrically-powered blower as recited in claim 1 wherein said electric heater is connected in series through said motor switch so that said heater can be energized only when said blower wheel is rotating.

(References on following page) 5 6 References Cited by the Examiner 2,622,186 12/ 1952 Hutchens 2 00-139 X 2,765,393 10/1956 Theisen 2l9369 X UNITED STATES PATENTS 2,988,626 6/1961 Butiner 219-3 69 X 758,303 4/1904 Eckman 219-474 X 3,039,942 5/1963 Wrigglesworth 219--364 X 1,465,292 3/1923 Wfisslg 219 4 5 14 312 2 19 3 LevimL 1,564,396 12/1925 Rinker et a1 219370 3 2 2 797 g 19 5 Uthoff 7 1,868,905 7/1932 Kelley 219-371 2,041,687 5/1936 Benson 219-470 FOREIGN PATENTS 2,074,018 3/1937 Gross 34100 690,306 6/1930 France. 2,432,067 12/1947 Morse 219369 X 486,623 11/1953 Italy. 2,591,669 4/1952 3116161611 et a1 219-470 10 2,611,855 9/1952 Turner 2G0139 X ANTHONY BARTIS, Primary Examiner.

Claims

1. AN ELECTRICALLY-POWERED BLOWER FOR A HAIR DRYER COMPRISING: (A) A CASING DEFINING A CENTRIFUGAL BLOWER CHAMBER AND HAVING AIR INLETS AND AN AIR DISCHARGE PORT; (B) A ROTATABLE BLOWER WHEEL WITHIN SAID BLOWER CHAMBER; (C) AN ELECTRIC DRIVE MOTOR WITHIN SAID CASING CONNECTED TO ROTATE SAID BLOWER WHEEL; (D) AN ELECTRIC HEATER POSITIONED WITHIN SAID CASING AND ADJACENT SAID DISCHARGE PORT; (E) A MOTOR SWITCH COMPRISING A FIRST STATIONARY CONTACT AND A MOVABLE SPRING ARM INCLUDING A CONTACT THEREON; (F) A THERMOSTATIC HEATER SWITCH ADJACENT SAID HEATER COMPRISING A SECOND STATIONARY CONTACT AND A FLEXIBLE BIMETAL ARM INCLUDING A CONTACT THEREON; AND (G) COMBINED MOTOR SWITCH AND THERMOSTATIC HEATER SWITCH CONTROL MEANS COMPRISING A ROTATABLE MEMBER INCLUDING AT ONE END THEREOF A DISC PORTION HAVING A SPIRAL CAM GROOVE THEREIN AND HAVING AN OUTER PERIPHERAL CAM SURFACE ENGAGING SAID SPRING ARM, AND AN ABUTMENT MEMBER SLIDABLY MOUNTED ON SAID BIMETAL ARM AND INCLUDING A PORTION RECEIVED IN SAID CAM GROOVE, SUCH THAT SELECTIVE ROTATION OF SAID ROTATABLE MEMBER MOVES SAID SPRING ARM CONTACT INTO AND OUT OF ENGAGEMENT WITH SAID FIRST STATIONARY CONTACT AND POSITIONS SAID ABUTMENT ALONG SAID BIMETAL ARM.