Patent Publication Number: US-9409300-B2

Title: Open cutter for a foil type shaver and method for fabricating the open cutter

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a Divisional Application of U.S. patent application Ser. No. 13/943,770, filed on Jul. 16, 2013. This application is incorporated herein by reference. 
    
    
     FIELD OF TECHNOLOGY 
     The present application relates to an open cutter for a foil type shaver and a method for fabricating the open cutter. 
     BACKGROUND 
     An open cutter is one of the most popular types of cutter used in a foil type shaver. It is basically a bent metal sheet that is slotted in between to form cutting edges. The bent slotted metal sheet is then housed on a plastic or metal bridge that can be driven by a motor and oscillate side by side through an eccentric pin. On top of the open cutter is a flexible thin metal sheet with through-hole pattern on it. This flexible thin metal sheet is also known as a foil. The cutting of hair takes place when the open cutter is sliding on the inner surface of the foil. The hair passing through the through-holes of the foil can be cut by the open cutter oscillating at high speed. The cutting action is an interaction between the foil and the open cutter. 
     The above description of the background is provided to aid in understanding an open cutter for a foil type shaver, but is not admitted to describe or constitute pertinent prior art to the open cutter for a foil type shaver disclosed in the present application, or consider any cited documents as material to the patentability of the claims of the present application. 
     SUMMARY 
     According to one aspect, there is provided an open cutter for a foil type shaver. The open cutter may include a plurality of arch-shaped cutting strips formed by bending a metal plate formed with alternating parallel slots and cutting strips. Each arch-shaped cutting strip may have two opposite sides and a top surface in sliding contact with an underneath surface of an arcuate foil through which hair to be cut can pass. A plurality of protruding cutting edges can be formed along the two opposite sides of the arch-shaped cutting strips and spaced apart from each other. Each protruding cutting edge can be defined by an extension of the top surface of the cutting strip and a bottom surface inclined at a first acute angle with respect to the extension of the top surface. A plurality of recessed cutting edges can be defined by the plurality of protruding cutting edges. Each recessed cutting edge can be defined by the top surface of the cutting strip and the side of the cutting strip inclined at a second acute angle with respect to the top surface. The protruding cutting edges of one cutting strip may be facing the recessed cutting edges of an adjacent cutting strip, thereby generating continuous hair-lifting and hair-cutting actions as the open cutter is driven in oscillating directions by a motor. 
     In one embodiment, the first acute angle is about 45°, and the second acute angle is greater than 75°. The plurality of arch-shaped cutting strips may be disposed at an oblique angle with respect to the oscillating directions. The oblique angle may be between 5° and 15°. The plurality of arch-shaped cutting strips may also be disposed perpendicular to the oscillating directions. The thickness of the metal plate may be less than 1 mm and the metal plate may be made of stainless steel. 
     According to another aspect, there is provided a method for fabricating an open cutter for a foil type shaver including the steps of (i) stamping a metal plate to form thereon alternating parallel slots and cutting strips, each cutting strip having two opposite sides and a top surface; (ii) shearing the stamped metal plate to form a plurality of protruding cutting edges along the two opposite sides of the cutting strips and spaced apart from each other, each protruding cutting edge being defined by an extension of the top surface of the cutting strip and a bottom surface inclined at a first acute angle with respect to the extension of the top surface; and a plurality of recessed cutting edges defined by the plurality of protruding cutting edges, each recessed cutting edge being defined by the top surface of the cutting strip and the side of the cutting strip inclined at a second acute angle with respect to the top surface; and (iii) forming the cutter having a plurality of arch-shaped cutting strips by bending the stamped and sheared metal plate into an arch shape. 
     The method may further include the step of profile grinding the formed cutter. The first acute angle formed at the protruding cutting edges may be about 45°, and the second acute angle formed at the recessed cutting edges may be greater than 75°. The metal plate may be made of stainless steel. 
     According to yet another aspect, there is provided a foil type shaver including an arcuate foil and an open cutter slidably coupled underneath the arcuate foil. The open cutter may include a plurality of arch-shaped cutting strips formed by bending a metal plate formed with alternating parallel slots and cutting strips. Each arch-shaped cutting strip may have two opposite sides and a top surface in sliding contact with an underneath surface of the arcuate foil through which hair to be cut can pass. A plurality of protruding cutting edges may be formed along the two opposite sides of the arch-shaped cutting strips and spaced apart from each other. Each protruding cutting edge being can be defined by an extension of the top surface of the cutting strip and a bottom surface inclined at a first acute angle with respect to the extension of the top surface. A plurality of recessed cutting edges can be defined by the plurality of protruding cutting edges. Each recessed cutting edge can be defined by the top surface of the cutting strip and the side of the cutting strip inclined at a second acute angle with respect to the top surface. The protruding cutting edges of one cutting strip may be facing the recessed cutting edges of an adjacent cutting strip, thereby generating continuous hair-lifting and hair-cutting actions as the open cutter is driven in oscillating directions by a motor. 
     In one embodiment, the first acute angle may be about 45°, and the second acute angle may be greater than 75°. The plurality of arch-shaped cutting strips may be disposed at an oblique angle with respect to the oscillating directions. The oblique angle may be between 5° and 15°. The thickness of the metal plate may be less than 1 mm, and the metal plate may be made of stainless steel. 
     Although the open cutter for a foil type shaver disclosed in the present application is shown and described with respect to certain embodiments, it is obvious that equivalents and modifications will occur to others skilled in the art upon the reading and understanding of the specification. The present application includes all such equivalents and modifications, and is limited only by the scope of the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Specific embodiments of the open cutter for a foil type shaver disclosed in the present application will now be described by way of example with reference to the accompanying drawings wherein: 
         FIG. 1  is a top view of a stamped metal plate for forming into an open cutter according to an embodiment of the present application. 
         FIG. 2  is a perspective of the open cutter formed from the stamped metal plate of  FIG. 1  into an arcuate configuration according to an embodiment of the present application. 
         FIG. 3  is a top view of the open cutter in  FIG. 2 . 
         FIG. 4  is a side view of the open cutter in  FIG. 2 . 
         FIG. 5  is an end view of the open cutter in  FIG. 2 . 
         FIG. 6  is a bottom view of the open cutter in  FIG. 2 . 
         FIG. 7  is an enlarged cut-away top view of the open cutter in  FIG. 2 . 
         FIG. 8  is a cross sectional view of two cutting strips taken along line A-A in  FIG. 7 . 
         FIG. 9  is a cross sectional view of one cutting strip taken along line B-B in  FIG. 7 . 
         FIG. 10  is an enlarged fragmentary view of three cutting strips of the open cutter. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to a preferred embodiment of the open cutter for a foil type shaver disclosed in the present application, examples of which are also provided in the following description. Exemplary embodiments of the open cutter for a foil type shaver disclosed in the present application are described in detail, although it will be apparent to those skilled in the relevant art that some features that are not particularly important to an understanding of the open cutter for a foil type shaver may not be shown for the sake of clarity. 
     In addition, improvements and modifications which may become apparent to persons of ordinary skill in the art after reading this disclosure, the drawings, and the appended claims are deemed within the spirit and scope of the appended claims. 
     Certain terminology is used in the following description for convenience only and is not limiting. The words “upper”, “lower”, “top”, and “bottom” designate directions in the drawings to which reference is made. The terminology includes the words noted above as well as derivatives thereof and words of similar import. 
       FIG. 1  shows a metal plate  12  for forming into an open cutter  10  for a foil type shaver according to an embodiment of the present application. The metal plate  12  may be formed with alternating parallel slots  14  and cutting strips  16  by stamping. The thickness of the metal plate  12  may be less than 1 mm. The metal plate  12  may be made of stainless steel or any other suitable material. 
       FIG. 2  depicts the open cutter  10  having a plurality of arch-shaped cutting strips  16  formed by bending the metal plate  12  along its longitudinal axis. The plurality of arch-shaped cutting strips  16  may be parallel to each other and spaced along the oscillating directions of the open cutter  10 , as shown by the arrows in  FIG. 3 . Each arch-shaped cutting strip  16  may have two opposite sides  20 ,  22  and a top surface  30 . 
     One of the two opposite sides  20  may be generally facing one of the oscillating directions; whereas the other one of the two opposite sides  22  may be generally facing the other oscillating direction. The top surfaces  30  are arcuate in shape and are in sliding contact with an underneath surface of an arcuate foil (not shown) through which hair to be cut can pass. 
       FIGS. 3 to 6  are different views of the open cutter  10  of  FIG. 2 . The plurality of arch-shaped cutting strips  16  may be disposed at an oblique angle θ 3  with respect to the oscillating directions, as illustrated in  FIG. 3 . It is appreciated by one skilled in the art that the plurality of arch-shaped cutting strips  16  at an oblique angle can provide a better catch and shearing force for the hair. The oblique angle θ 3  may be between 5° and 15°. According to the illustrated embodiment, the plurality of arch-shaped cutting strips  16  may be oriented at 8° with respect to the oscillating directions. 
     Although it has been shown and described that the plurality of arch-shaped cutting strips  16  is disposed at an oblique angle with respect to the oscillating directions, it is understood that the plurality of arch-shaped cutting strips  16  can also be disposed perpendicular to the oscillating directions. 
     As depicted in  FIGS. 7 and 10 , a plurality of protruding cutting edges  40  may be formed along the two opposite sides  20 ,  22  of the cutting strips  16  and spaced apart from each other. The plurality of protruding cutting edges  40  is generally teeth-shaped. Each protruding cutting edge  40  can be defined by an extension  42  of the top surface  30  of the cutting strip  16  and a bottom surface  44  inclined at a first acute angle θ 1  with respect to the extension  42  of the top surface  30  of the cutting strip  16 , as shown in  FIG. 8 . According to the illustrated embodiment in  FIG. 8 , the first acute angle θ 1  or cutting angle is about 45°. 
     A plurality of recessed cutting edges  50  can be formed between and defined by the plurality of protruding cutting edges  40 . Each recessed cutting edge  50  can be defined by the top surface  30  of the cutting strip  16  and the side  20 ,  22  of the cutting strip  16  inclined at a second acute angle θ 2  with respect to the top surface  30  of the cutting strip  16 , as shown in  FIG. 9 . The second acute angle θ 2  or cutting angle may be greater than 75°. 
     According to the illustrated embodiment, there are 6-7 protruding cutting edges  40  and 6-7 recessed cutting edges  50  formed on each side of the cutting strips  16 , although the number may vary. The protruding cutting edges  40  and the recessed cutting edges  50  may have the same length. According to one embodiment, the length of the protruding cutting edges  40  and the recessed cutting edges  50  is about 0.5 mm. 
     According to the illustrated embodiment, the open cutter  10  has  27  arch-shaped cutting strips  16  although the number may vary depending on the size of the shaver. The distance between two protruding cutting edges  40  of two adjacent cutting strips  16  may be about 0.8 mm. 
     The protruding cutting edges  40  of one cutting strip  16  may be facing the recessed cutting edges  50  of an adjacent cutting strip  16 , thereby generating continuous hair-lifting and hair-cutting actions as the open cutter  10  is driven in the oscillating directions by a motor. 
     The open cutter  10  can be fabricated by stamping, shearing and forming processes. The open cutter  10  may be fabricated by first stamping the metal plate  12  to form thereon the alternating parallel slots  14  and cutting strips  16  using a conventional metal stamping machine. Each cutting strip  16  would have two opposite sides  20 ,  22  and a top surface  30 . 
     Thereafter, the stamped metal plate  12  may be sheared by suitable metal shearing tools to form a plurality of protruding cutting edges  40  along the two opposite sides  20 ,  22  of the cutting strips  16  and spaced apart from each other. Each protruding cutting edge  16  can be formed by an extension  42  of the top surface  30  of the cutting strip  16  and a bottom surface  44  inclined at a first acute angle θ 1  with respect to the extension  42  of the top surface  30 . A plurality of recessed cutting edges  50  can be formed and defined by the plurality of protruding cutting edges  40 . Each recessed cutting edge  50  can be formed by the top surface  30  of the cutting strip  16  and the side  20 ,  22  of the cutting strip  16  inclined at a second acute angle θ 2  with respect to the top surface  30  of the cutting strip  16 . 
     According to the illustrated embodiment, the first acute angle θ 1  formed at the protruding cutting edges  40  may be about 45° and the second acute angle θ 2  formed at the recessed cutting edges  50  can be greater than 75°. 
     The plurality of arch-shaped cutting strips  16  can then be formed by bending the stamped and sheared metal plate  12  into an arch shape. Finally, profile grinding may be performed on the formed open cutter  10 . 
     While the open cutter for a foil type shaver disclosed in the present application has been shown and described with particular references to a number of preferred embodiments thereof, it should be noted that various other changes or modifications may be made without departing from the scope of the appending claims.