Abstract:
A hair dryer is provided with a high voltage generator which produces a negative DC voltage output of at least about 6 kilovolts for reducing static charges on a person&#39;s hair during hair drying. The generator can be mounted adjacent the dryer air inlet of the hair dryer housing to cool the generator with cooling air, or the generator can be mounted externally of the dryer to reduce dryer weight.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates in general to hot-air hair dryers and relates particularly to a hot-air hair dryer which produces negative ions using a high-voltage transformer. 
     2. Description of Prior Developments 
     It is well known that combing and brushing one&#39;s hair can impart a static electrical charge on the hair. This is generally considered undesirable insofar as statically charged hair is difficult to manage and can attract airborne dust and dirt. 
     Since one&#39;s hair is often brushed or combed when being dried by a conventional hair dryer, some hair dryers have been provided with ion generators to neutralize the static charge created by combing and brushing during hair drying. Although these prior hair dryers generally function satisfactorily, they often rely on the use of piezoelectric generators to produce ions. These generators must be mechanically operated by a user and are not particularly convenient to use. 
     Some prior ion-generating hair dryers have used voltage generators to produce ions, but the voltages produced have been relatively low, such as 1600 to 1700 volts applied to a negative ion emitter. Moreover, conventional voltage generators are relatively bulky and heavy and result in a relatively large hair dryer assembly. 
     Accordingly, a need exists for an ion-emitting hair dryer which produces relatively highly charged negative ions and which requires a single ion generator. 
     A further need exists for such a hair dryer which is compact, lightweight, easy-to-use and which avoids the use of manually-actuated piezoelectric ion generators. 
     SUMMARY OF THE INVENTION 
     The present invention has been developed to fulfill the needs noted above, and therefore has as an object the provision of a hair dryer which emits highly charged negative ions for neutralizing the static charge on hair as it is being brushed or combed and dried. 
     A further object of the invention is the provision of an ion-emitting hair dryer which uses a high-voltage transformer to produce highly charged negative ions. 
     Another object of the invention is to provide a hair dryer having a high-voltage transformer located in the ambient air intake flow path of the dryer. 
     Yet another object of the invention is the provision of an ion-emitting hair dryer having a high-voltage transformer located on the exterior of the hair dryer. 
     These and other objects are met by the present invention which is directed to an ion-emitting hair dryer having a transformer which produces a negative electrical charge of at least about 6000 volts. This relatively high negative voltage significantly improves the manageability of ionized or statically-charged hair. A negative ion-generating electrode can be located in a conventional manner near the outlet of the hair dryer or at a position between the fan and the heating coil of the hair dryer. 
     The transformer can be advantageously located at the intake side of the dryer fan to receive cooling intake air, or the transformer can be located on the exterior of the hair dryer, such as on the power cord. In this latter case, the elimination of the transformer from the body of the hair dryer significantly reduces the weight of the hair dryer and thereby increases its ease of use. 
     The aforementioned objects, features and advantages of the invention will, in part, be pointed out with particularity, and will, in part, become obvious from the following more detailed description of the invention, taken in conjunction with the accompanying drawings, which form an integral part thereof. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings: 
     FIG. 1 is a schematic view, partially in section, showing an negative-ion-emitting hair dryer constructed in accordance with a first embodiment of the invention, and showing alternate constructions in dashed lines; 
     FIG. 2 is a perspective view of the hair dryer of FIG. 1 fitted with a removable nozzle; and 
     FIG. 3 is a schematic view of a wiring circuit adapted for use with the hair dryer of FIG.  1 . 
     In the various figures of the drawings, like reference characters designate like parts. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention will now be described in conjunction with the drawings, beginning with FIGS. 1 and 2 which show a negative-ion-emitting hair dryer  10  constructed in accordance with the invention. The dryer includes a hollow handle  12  connected to a tubular housing  14 . 
     As seen in FIG. 2, a removable nozzle  15  can be fitted on the outlet end of the tubular housing  14 . A power cord  16  supplies electric power to switch  18  from plug  20 , which is typically plugged into a conventional electrical outlet. 
     Switch  18  distributes electrical power to a high-voltage DC generator  22  which is located within tubular housing  14  between a circular ambient-air inlet  24  and a cylindrical tubular fan housing  26 . A motor  28  also receives electrical power from switch  18  to drive fan blade  30 . The motor  28  and blade  30  form a fan unit. Air drawn into the tubular housing  14  through inlet  24  by fan blade  30  advantageously flows over generator  22  and thereby cools the generator before entering the fan housing  26 . 
     A heating coil assembly  32  is mounted in tubular housing  14  in front of the fan blade  30  and fan housing  26 . A heating coil  34  receives electrical power from switch  18  in a known fashion. An ion-emitting metal pin or electrode  36  is mounted on the front center of the heating coil assembly  32  for producing negative ions in the air  38  which flows past the electrode  36 . 
     Although the electrode  36  functions well when located as shown at the front of the heating coil assembly  32  adjacent air outlet  40 , it has been found that the electrode  36  also functions well when located, as shown in dashed lines, between the fan blade  30  and the heating coil  32 . Another design alternative is to locate the high voltage generator  22  on the exterior of tubular housing  14  and handle  12  and wrapping and taping its wiring around the power cord  16  and running its wiring through the bottom of handle  14 . By locating the voltage generator  22  on the power cord  16 , adjacent plug  20 , the weight of the generator  22  can be removed from the hand-held hair dryer. This improves the maneuverability of the dryer  10 . However, the alternative placement of the voltage generator  22  next to inlet  24  helps to balance the hair dryer  10  in one&#39;s hand, so there are benefits to be achieved with either an internal or external mounting of voltage generator  22 . 
     Voltage generator  22  can take the form of a commercially available transformer such as a unit available from FUFONG as model FA1-7-2. This unit receives 120 volts at 50 to 60 Hz and provides a negative DC voltage output of 7 kilovolts. It has been found that 7 KV of negative voltage produces a most satisfactory ionization of the air  38  for the purpose of neutralizing the positive charge on a person&#39;s hair during hair drying. 
     A schematic circuit diagram is shown in FIG. 2 for use with the hair dryer  10  of FIG.  1 . Switch  18  is a commercially available three-position switch sold by DEFOND under model number DPW-1211. Switch  18  provides an off condition, and two power settings with one rated at 11 amps at 120 volts AC and the other rated at 6 amps at 250 volts AC. A trigger switch  43  is provided on switch  18  for cycling through the three switch positions. 
     As further seen in FIG. 3, a temperature responsive switch  44  can be mounted next to the heating coil  34  to shut off power to the heating coil if it becomes excessively hot. The plug  20  can include a circuit breaker  21  and reset switch  23  for protecting the hair dryer from overloading on power. Such a plug is available from Tower Switches Ltd. as catalog model No. 303. 
     When the switch  18  is triggered into its first on position, power is fed to the voltage generator  22 , fan motor  28  and heating coil  34 . Cool air is drawn into inlet  24 , over the voltage generator  22 , through the fan housing  26 , over the heating coil  34 , over the negatively-charged electrode  36  and out of the tubular housing  14  through outlet  40 . 
     Heated negative ions exit outlet  40  and may be directed onto a person&#39;s hair to neutralize the typically positively-charged hair. As noted above, brushing and combing one&#39;s hair can cause the hair to become positively charged and difficult to style and hold neatly in place. However, when negative ions are applied by hair dryer  10  during such brushing and combing, the positively charged hair is neutralized in charge and becomes much more manageable. 
     There has been disclosed heretofore the best embodiment of the invention presently contemplated. However, it is to be understood that various changes and modifications may be made thereto without departing from the spirit of the invention.