Hair curling device having wavy heating surfaces with asymmetrically sized crest and trough portions

Abstract

The techniques introduced here improve the effectiveness of a hair curling iron's heating surfaces without adding bulk. The device includes two elongated arms, each carrying a heating surface, connected by a pivot. The device's configuration allows the arms to open and close, forming a transverse wave-shaped heating area when the heating surfaces are interlocked with each other. Some embodiments of the heating area include a larger central wave that creates a dominant visual feature, and two smaller waves that can blend seamlessly with the adjacent large waves, resulting in an overall hairstyle that is full and voluminous. Some embodiments include hair volumizing cavity envelopes to reduce tension and friction, preventing hair pinching. Additionally, or alternatively, the crease-reduction gaps can reduce the likelihood of hair creases.

What is claimed is: 
     
         1 . A hair curling device comprising:
 an elongated first arm carrying a first heating surface; and   an elongated second arm carrying a second heating surface;   wherein the first and second heating surfaces are arranged to face each other,   wherein the first and second arms are connected at a pivot, the pivot allowing user manipulation of at least one of the first and second arms in a relative manner to form (1) an open position where the first and second heating surfaces are not interlocked, and (2) a closed position where the first and second heating surfaces are interlocked,   wherein the first and second heating surfaces, when interlocked, together form a heating area having a cross-section that resembles a transverse wave shape, the transverse wave shape including a crest portion and two trough portions, the crest portion being located between, and adjacent to, the two trough portions, and   wherein the two trough portions are symmetrical to each other about a vertical axis, yet asymmetrical to the crest portion about a lateral axis.   
     
     
         2 . The device of  claim 1 , wherein the crest portion has a larger dimension than the two trough portions. 
     
     
         3 . The device of  claim 2 , wherein said larger dimension includes height, width, and/or radius. 
     
     
         4 . The device of  claim 2 , wherein said larger dimension is at least 25% larger. 
     
     
         5 . The device of  claim 2 , wherein the heating area includes two hair volumizing cavity envelopes, each cavity envelope located at about a waist location where the crest portion meets one of the two trough portions. 
     
     
         6 . The device of  claim 5 , wherein a cross-section of a hair volumizing cavity envelope resembles an English letter “S.” 
     
     
         7 . The device of  claim 5 , wherein a lateral dimension of a cavity envelope is between 0.5 mm to 2 mm. 
     
     
         8 . The device of  claim 1 , wherein, when the first and second arms are in the closed position, two crease-reduction gaps are formed, each crease-reduction gap located at one of the two outer lateral edges of the interlocked first and second heating surfaces. 
     
     
         9 . The device of  claim 8 , wherein a width of a crease-reduction gap is between 1 mm to 3 mm. 
     
     
         10 . The device of  claim 1 , wherein the highest point of the crest portion defines a crest in the transverse wave shape, wherein the lowest points of the two trough portions define two troughs in the transverse wave shape, and wherein the one crest and the two troughs form an isosceles triangle but not an equilateral triangle. 
     
     
         11 . The device of  claim 10 , wherein the isosceles triangle that has an apex angle that is between 45 degrees and 70 degrees. 
     
     
         12 . The device of  claim 10 , wherein the isosceles triangle that has an apex angle that is between 55 degrees and 65 degrees. 
     
     
         13 . The device of  claim 10 , wherein the length of two legs of the isosceles triangle is between 25 mm to 45 mm. 
     
     
         14 . The device of  claim 10 , wherein the length of the base of the isosceles triangle is between 30 mm to 50 mm. 
     
     
         15 . The device of  claim 10 , wherein a height difference between the crest and the two troughs is between 20 mm to 32 mm. 
     
     
         16 . The device of  claim 10 , wherein a width of the crest portion is between 17 mm to 27 mm. 
     
     
         17 . The device of  claim 1 , wherein the transverse wave shape resembles the English letter “W” or “M.” 18 . The device of  claim 1 , wherein a central angle of the crest portion is larger than a central angle of the trough portions. 
     
     
         19 . The device of  claim 1 , further comprising:
 a sensor that detects whether the first and second arms are in the closed position; and   a timer that is coupled to the sensor,   wherein, when the first and second arms are in the closed position, the sensor is configured to trigger the timer to start.   
     
     
         20 . The device of  claim 19 , further comprising:
 a switch operable to adjust the timer by a user, wherein the timer is configured to control an operation mode of the device.