Abstract:
A dual in-line portable electric hair drying appliance includes independently operational heaters to provide optimized performance and a multitude of operating conditions that are found to be advantageous in the drying and styling of hair.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to hair-drying and styling appliances. More specifically, the present invention is a hand-held electric hair-drying and styling appliance comprising independently controlled dual in-line drying barrels. 
     BACKGROUND OF THE INVENTION 
     Hand-held electric hair-drying and styling appliances are well known. In such prior art dryers, it is most common to employ a single tubular barrel in which is housed a heating element and through which is directed airflow from a blower, which airflow is heated by the heater and exhausted from the barrel toward the hair for drying or styling thereof. 
     It has been recognized that there are advantages to diffusing and splitting the heated airflow into two or more individual air streams. U.S. Pat. Nos. Des. 425,664 and Des. 380,540, and EPO patent application 0400381-A2, depict such prior art dual in-line hair-dryers. A deficiency of these prior art dryers is that they lack independence between the two heated air streams. Because the air streams are both heated by the same heating element and propelled by the same blower, both air streams must inherently operate the same at any given time. 
     It is found that the styling effects of the dual air streams are enhanced when one air stream is operated at a cooler temperature than the other. The curling effects realized when the hair is treated by dual air streams having such differing temperatures is found to be unique; curls in straight hair are better created and natural curliness is accentuated. This is possibly the result of having the hair subjected to a hot air stream, then cooler air, and then another hot air stream as the dryer is passed over the hair, or possibly the result of the uneven tempering of the hair when the dryer is held still. 
     Another disadvantage to prior art dual in-line hair-dryers is that they require a dedicated heater/blower subassembly. Many manufacturers of such appliances also manufacture other single barrel dryers and desire to reduce the inventory of components. The ability to share components between various models can be extremely economical and advantageous. The ability to use a pair of heater/blower subassemblies that are also shared with other single barrel models would provide numerous manufacturing advantages. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an improved portable electric hair-drying and styling appliance. 
     It is a further object to provide a dual in-line portable electric hair-drying and styling appliance in which the heat from each barrel is independently controllable. 
     It is a further object of the present invention to provide a dual in-line portable electric hair-drying and styling appliance that uses a pair of heater/blower subassemblies which are common to another drying appliance so that the inventory of those subassemblies may be economically shared in the manufacturing of this and that other appliance. 
     It is still a further object to provide a dual in-line portable electric hair-drying and styling appliance having all of the above advantages. 
     Further objects and advantages of the present invention will be best appreciated and more fully understood in reference to the herein described preferred embodiment and the appended drawings, of which the following is a brief description. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded assembly of a dual in-line portable electric hair-drying and styling appliance in accordance with the preferred embodiment of the invention; 
     FIG. 2 is a view of the appliance of FIG. 1 from the exhaust end; 
     FIG. 3 is a view of the appliance of FIG. 1 from the intake end; 
     FIG. 4 is a side view of the appliance of FIG. 1; 
     FIG. 5 is a side sectional view of the appliance of FIG. 1; and 
     FIG. 6 is a diagram of the electrical circuit of the appliance of FIG.  1 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A dual in-line portable electric hair-drying and styling appliance  100  in accordance with the preferred embodiment of the invention is depicted in FIGS. 1 through 5. 
     Housing  101  includes front portion  102  and rear portion  103 , which join together along seam  104  and are attached by screws (not shown). Once joined, housing  101  forms an upper head portion  105 , and a lower handle portion  106 . The head portion comprises a left barrel  107 L and a right barrel  107 R. Inside the housing, barrel separator  110  separates the left and right barrels. The housing head and separator thereby form a hollow shell around each of the barrels to create interior ducts  111 L and  111 R, which each function as an air flow channel. 
     At the rear most end  112  of the barrels are provided intake grills  115 L and  115 R, for allowing air to enter each barrel, and at the opposite end  113  are provided exhaust grills  116 L and  116 R for allowing that air to escape towards the hair (not shown). 
     Within each barrel is positioned a heater/blower subassembly  120 L or  120 R which each comprises a motor  121 L or  121 R, a fan blade  122 L or  122 R, a heating element  123 L or  123 R, and a fan housing  124 L or  124 R to which these components are mounted to form together the heater/blower subassembly. The subassemblies are each fitted within the left and right interior ducts before the front and rear housings are fitted together to thereby align and encapsulate the subassemblies. 
     Each of the heating elements is adapted for either high, medium, or low temperature operation. 
     The blowers comprise axial fans each having a rotation tangent to the airflow direction within the associated barrel. The left motor  121 L supplies airflow through the left barrel and the right motor  121 R supplies airflow through the right barrel. 
     The identical heater/blower subassemblies  120 L and  120 R are each comprised of components that are standard to other single barrel hair-dryers. Aside to other advantages, this commonality of components reduces the need to inventory additional components and thereby improves the economy of manufacturing this appliance. 
     Within the handle portion are located two switches; right barrel switch  130  and left barrel switch  131 . The switches are connected to a standard power supply through power supply cord  132 . Each switch is then connected to the appropriate heating element to independently control the temperature thereof. Each switch is a multi-position slide switch including “Off”, “Cool”, “Warm”, and “Hot” positions, and controls the appropriate heating element according to that condition. In this way, each of the left and right barrels can provide any of the four conditions of operation while the other barrel can independently provide the same or any other one of these conditions, thereby providing up to sixteen distinct operating conditions for the appliance. 
     In the “Off” condition, the appropriate barrel is de-energized so that the motor and heating element are not operational. In the “Cool” condition, the appropriate heating element is energized at 300 Watts so that relatively cool air flows from that barrel. In the “Warm” condition, the appropriate heating element is energized at 600 Watts so that warm air flows from that barrel. In the “Hot” condition, the appropriate heating element is fully energized at 900 Watts so that hot air flows from that barrel. It can be appreciated that any combination of these wattages can be simultaneously delivered from the pair of barrels. 
     It is found that simultaneously operating each barrel at different temperatures results in unique curling effects on the hair. For instance, operating the left barrel on “Cool” while operating the right barrel on “Hot” causes the hair to curl more to the left. Alternately, operating the right barrel on “Cool” while operating the left barrel on “Hot” would cause that hair to curl more to the right. 
     The aforesaid ability for the present invention to operate in such an asymmetrical manner makes it desirable for the appliance to be equally convenient for operation with the right or left hand, so that the appliance can be moved from one side of the head to the other. For instance, it may be desirable to use the dryer on the right side of the head with the right hand and with the right barrel operating on a cooler setting than the left, then to move the appliance to the left side of the head and into the left hand and change the setting so that the left barrel is operating on a cooler setting than the right. This would be a practical method for causing the hair on both sides of the head to curl forward. It is therefore desirable to change the operational conditions with either hand. Switches  130  and  131  are therefore symmetrically positioned and adapted for equally convenient operation by either the right or left hand. 
     It is also found that simultaneously operating each barrel under the same condition results in more efficient hair-drying, as a result of the improved dispersement of the airflow versus traditional single barrel appliances. 
     Those skilled in the art will recognize that there are many variations of the invention that are within the scope of the invention, therefore, the invention is to be defined only by the limitations and the equivalents thereof which the following claims set forth.