Abstract:
A curling iron having a variable timer to control audible signals that are referenced to and adjusted according to the actual temperature of the barrel as well as to the curl setting. The temperature of the barrel and the curl setting can be adjusted by the user, which alters the signaled time of exposure. A turbo setting can be employed to rapidly increase the temperature of the barrel.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a continuation-in-part application and claims priority to U.S. application Ser. No. 10/930,099, filed Aug. 31, 2004, which claims priority in U.S. Provisional Patent Application Ser. No. 60/501,118, filed Sep. 8, 2003, the disclosures of which are incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to an electrical curling iron, which employs an audible signal controlled by a variable timer and which varies temperature and time to accommodate ambient conditions.  
         [0004]     2. Description of Related Art  
         [0005]     It is known in the art to provide an electrical curling iron with an audible signal switched by a timer to indicate the recommended duration of application of the curling iron to the hair. Such a signal indicates the optimum time of exposure to the hot iron and intends to protect against burning the hair as well as offering a choice of loose or tight curls.  
         [0006]     It is also well known in the art of curling irons to offer variable barrel temperatures. Currently manufactured appliances offer a temperature spread from low to high of as much as seventy degrees C. There is, however, a problem in offering both variable temperature and variable time indication as the tightness of the curl is directly proportional to both time of exposure and the temperature. A curling iron that features a time setting that is ignorant of the temperature setting will have uncertain results. There is a need therefore for a curling iron control that coordinates the time and temperature together with a common logic to gauge the resulting curl.  
         [0007]     The barrel temperature of a curling iron depends on the power supplied to the heated element as well as the accuracy of the temperature control. The surface temperature is quickly reduced in application to hair and all controllers have a window of accuracy within which they are ignorant of the actual temperature. The size of this window in prior art curling irons has been as much as 30 degrees C. Such swings in temperature can significantly affect the necessary time of exposure to set a curl. If the barrel is operating at the extremes of the normal temperature, the audible signal can be inaccurate. There is, therefore, a need for feedback between the actual barrel temperature and the time signal.  
         [0008]     Another characteristic of prior art curling irons with electronic timer and audible signal is that the signal has been indicated with only one sound. The time setting could only be determined by the switch position. Since curling irons are generally used behind the head, there is need for a more meaningful audible signal that can indicate by the sound the actual setting being employed and whether the curl is tight or loose.  
       OBJECT AND SUMMARY OF THE INVENTION  
       [0009]     It is an object of the present invention to provide a novel control system for a curling iron that addresses the above-mentioned shortcomings of the prior art. These and other objectives are achieved by the present invention described herein.  
         [0010]     The present invention is directed to a novel application in a curling iron of a variable timer to control audible signals that are referenced to and adjusted according to the actual temperature of the barrel as well as to the curl setting.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]     The present invention is more fully understood by reference to the following detailed description of an illustrative embodiment with the drawings identified below.  
         [0012]      FIG. 1  is an orthographic illustration of a preferred embodiment of a curling iron with an LCD display.  
         [0013]      FIG. 2  is an illustration of the LCD display on the preferred embodiment of an electronic curling iron with an audible signal.  
         [0014]      FIG. 3  is an illustration of the LED display on the preferred embodiment of an electronic curling iron with an audible signal.  
         [0015]      FIG. 4  is an illustration of an electronic circuit diagram according to the preferred embodiment of an electronic curling iron with audible signal.  
         [0016]      FIG. 5  is an illustration of a timing diagram according to the preferred embodiment of an electronic curling iron with audible signal.  
         [0017]      FIG. 6  is an illustration of pin assignments and pin descriptions according to the preferred embodiment of an electronic curling iron with audible signal. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0018]      FIG. 1  illustrates the preferred embodiment of a curling iron with electronic temperature controls to control the heater ( 8 ), and an LCD display ( 1 ). The present invention, of an improved curling iron, features an audible signal generator ( 9 ) that emits an audible signal to indicate the time elapsed from start. The time elapsed is that exposure time relative to the actual barrel temperature necessary to set a loose or tight curl. The improved curling iron operates such that an increase in the barrel temperature will automatically decrease the signaled time of exposure and a decrease in the temperature will automatically result in a longer signaled time of exposure. In the preferred embodiment this is accomplished with an electronic circuit that references a thermally sensitive component in proximity to the barrel, the details of the circuit logic can be accomplished with various well-known circuit designs. An LCD display panel ( 2 ) is employed in the preferred embodiment of the curling iron.  
         [0019]      FIG. 2  illustrates a typical LCD display, as it would appear on the control panel of the preferred embodiment. In this preferred embodiment an on/off button ( 6 ) would start the iron. A “curl timer button” ( 3 ) would then be depressed and held down while either plus or minus buttons ( 4 ) &amp; ( 5 ) are depressed to set the “tightness of curl” setting. The tightness of curl settings are “loose”, “medium”, or “tight”. After setting the desired curl tightness and releasing the “curl timer button” the audible signal countdown timer can be started or reset by momentarily depressing the same “curl timer button”. In an alternate embodiment, an LED display could be used, an example of which is illustrated in  FIG. 3 .  
         [0020]     The barrel temperature setting is indicated by the lit segments on a bar graph and by a numerical display, settings  1  thru  25 . The desired temperature setting can be increased or decreased by depressing the “plus” or “minus” buttons. In alternative embodiments the numerical display could also indicate the current actual barrel temperature.  
         [0021]     An additional feature on the preferred embodiment is the turbo setting. When the “Turbo” button ( 7 ) is depressed and held down, the barrel temperature will be increased 15-20 degrees C. above the current setting, for as long as the button is depressed. In an alternate embodiment, the “turbo” button can be pressed once, without the need to hold the button down. This would increase the barrel temperature by 15-20 degrees C. above the current setting within 30-60 seconds when the temperature is at a maximum setting. At times other than when the temperature is at a maximum setting, the barrel temperature would increase by 2-20 degrees C. When this “turbo” button is pressed, the two bars above the current setting on the bar graph would be illuminated to signify that the “turbo” button is engaged.  
         [0022]      FIG. 4  illustrates an example of an electronic circuit that may be used to accomplish these objectives. In  FIG. 4 a  NTC 500K sensor is shown. The unit&#39;s temperature is controlled by the means of this NTC sensor, which has a linear changeable resistance to temperature. The NTC is placed in a voltage divider circuit in a regulated 5.1 VDC power supply. The center of the voltage divider is connected to an NTC input on the integrated circuit.  
         [0023]     For normal operating temperature (without turbo) the chip is programmed so that when the voltage level reaches 1.54 volts the heater power controlled by an SCR from the gate the output of the chip will control the power output to the heater to a ½ duty cycle. When the voltage on the NTC input reaches 2.02 it will turn off the power to the heater. This circuit regulates the temperature of the curling iron or hair straightener. Other voltages can also be used to accomplish the intended results.  
         [0024]     When the turbo function is activated it now changes the program set points in the integrated circuit so that the change point from full duty cycle to ½ duty cycle now occurs a 1.69 volts instead of 5.4 volts and the off point is at 2.18 volts compared to 2.02. This effectively boosts the output temperature of the end product to a higher turbo set point. The NTC input points for normal and Turbo are shown in  FIG. 5 .  
         [0025]      FIG. 5  shows an exemplary timing diagram associated with the electronic circuit of  FIG. 4 .  FIG. 5  shows 2 duty cycles on the charts, level 0-2V and level 2.2 to 5. This is a control for an automatic dual voltage circuit that changes the duty cycle so at European voltages of 240 the duty cycle is ¼ to ⅛ and at 120 volts the duty cycle is full cycle to ½ cycle and off. In essence, the level input is the input for automatic dual voltage and is voltage divider directly related to the line in. The NTC is in voltage regulated circuit and is not affected by line voltage changes the normal and Turbo will work the same at both input voltages.  FIG. 6  illustrates an example of pin assignments and pin descriptions that may be used to obtain the intended results.  
         [0026]     While a preferred embodiment of the invention has been herein disclosed and described, it is understood that various modifications can be made without departing from the scope of the invention.