Patent Publication Number: US-2016226364-A1

Title: Electric Hair Clipper/Trimmer

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present invention claims priority to U.S. Provisional Application No. 62/109,649 entitled ELECTRIC HAIR CLIPPER/TRIMMER, filed on Jan. 30, 2015, the contents of which are herein incorporated by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The invention relates generally to electric hair clippers/trimmers, and, more particularly, to an electric hair clipper/ trimmer having an electromagnetic motor. 
     BACKGROUND OF THE INVENTION 
     Vibrator electromagnetic motors have been used in electric hair clippers for many years. Conventional vibratory electromagnetic motors have an electromagnet comprising a coil and associated core energized by a current of fixed frequency. A vibratory armature, mounted in spaced, effective relation with the core, can be connected to a work element as for example the reciprocating blade of a hair clipper. The armature, which forms a part of the magnetic circuit of the electromagnet, moves (vibrates or oscillates) in response to the varying magnetic field of the electromagnet, the permeability of the magnetic circuit varying with the travel path of the armature. 
     SUMMARY OF THE INVENTION 
     The present invention provides electric hair clipper including an electromagnetic motor with a fixed coil and a vibrating armature. The vibrating armature has a fixed end and a free end. A blade set is having fixed blade and a reciprocating blade are included, where the reciprocating blade is connected to the free end of the vibrating armature. A spring element can also be connected to the free end of the armature. 
     The vibrating armature has an armature spring rate and the spring element has a variable spring rate. The spring element can have a first spring rate through a first distance of travel of the free end of the vibrating armature and a second spring rate through a second distance of travel of the free end of the vibrating armature, wherein the first spring rate is less than the second spring rate. 
     The armature spring rate and the variable spring rate combine to control the movement of the reciprocating blade by varying the amount of energy absorbed by the vibrating armature and the spring element. The combination of the vibrating armature and the spring element can absorbed less energy at a minimum deflection point and more energy at maximum deflection point of the free end of the vibrating armature, when compared to a standard vibrating armature. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete understanding of the present invention, and the attendant advantages and features thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein: 
         FIG. 1  depicts a top isometric view of the electric clipper of the present disclosure; 
         FIG. 2  depicts a top isometric sectional view of the electric clipper of  FIG. 1 ; 
         FIG. 3 . depicts a top isometric sectional view of the front portion of the electric clipper of  FIG. 1   
         FIG. 4  depicts a front cross sectional view of the electric clipper of  FIG. 1 ; 
         FIG. 5  depicts a front isometric cross sectional view of the electric clipper of  FIG. 1 ; 
         FIG. 6  depicts and energy absorption table fir the electric clipper with a variable spring rate spring element. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings and, more particularly, to  FIG. 1 , a top elevation view of an electric hair cutting apparatus  10  according to the teachings of the present invention is shown. Electric hair cutting apparatus  10  includes a housing  12  which is generally hollow and houses the internal workings of the apparatus  10 . A manual switch  14  is provided for turning the apparatus  10  on and off. At one end of the apparatus  10  is a blade set  15 , include a fixed blade  16  and a reciprocating blade  18 , as is known in the art. The reciprocating blade  18  oscillates back and forth, left and right, so as to cut hair which enters between the teeth of the blades  16 ,  18 . 
       FIG. 2  is a  10  elevation view similar to  FIG. 1 , but with one side  11  of housing  12  removed for better viewing of the internal workings of the apparatus  10 . As can be seen, housing  12  houses a conventional vibratory electromagnetic motor  20  having a fixed coil  22  and a pole piece or core  24 . A vibratory armature  26  is disposed in effective relation with core  24 , an air gap  28  being present between the core  24  and armature  26 . 
     The vibrating armature  26  includes a resilient or elastic arm  28  which is anchored at one end  30  to a fixed support  32 , where in the vibrating armature  26  has an armature spring rate A sr  at a connection point. Referring also to  FIG. 3 , an opposite, free, end  34  of vibrating armature  26  is free to movie in a reciprocating motion upon activation of the electromagnetic motor  20 . A drive tip  38  is affixed to the free end  34  of the armature  26  at one end  40 , where an opposite end  42  of the drive tip  38  is connected to the reciprocating blade  18  of the bade set  15 . 
     Actuation of switch  14 , applies AC power to the fixed coil  22 , 60 Hertz line voltage is suitable, although square waves or any other suitable inductance inducing current would also work. The current in the fixed coil  22  produces magnetic flux which flows through the fixed coil  22 , vibrating the armature  26  across the air gap  28 . The vibrating armature  26  reciprocate back and forth as the coil  22  current changes direction, moving the reciprocating blade  18  over the fixed blade  16  of the blade set  15 , cutting the hair which is there between. 
     Referring also to  FIGS. 4-6 , a spring element  44  is connect between the free end  34  of the vibrating armature  26  and the second side housing  46  of the clipper housing  10 . In an embodiment, the spring element  44  is substantially U-shaped, having a center indented portion.  48  couples to the free end  34  of the vibrating armature  26 . The ends  50 ,  52  of the spring element  44  can be constrained by side wall  54  and  56  of the spring retainer  58  on the second side housing  46  of the clipper housing  10 . 
     The spring element  44  can have a variable spring rate S sr . The spring rate S sr  of the spring element  44  can increase with the travel distance of the armature  26 . The increase in the spring rate can be a non-linear rate increase, for example, a non-linear step or exponential function. The non-linear increase in the spring rate can limit the sweep distance of the moving blade  18 , as well as, provide better control thereof. 
     In operation, the armature spring rate A sr  and the variable spring rate S sr  combine to control the movement of the moveable blade  18  by varying the amount of energy absorbed by the vibrating armature  26  and the spring element  44 . The combination of the vibrating armature  26  and the spring element  44  can absorbed less energy at a minimum deflection point and more energy at maximum deflection point of the free end  34  of the vibrating armature, when compared to a standard vibrating armature. 
     In an embodiment, a standard vibrating armature can be 3 mm in thickness, with an armature spring rate A sr  of 145 lb/inch at the connection point. The proposed vibrating armature  26  can be 12 gage in thickness, with a proposed armature spring rate A sr  of 101 lb/inch at the connection point. The spring element  44  is connection to the end the proposed vibrating armature  26 , where the spring element  44  can have a variable spring rate S sr  of about 30 lb/in for the first 0.025 inches of travel of the free end  34  and 87 lb/in from 0.025-0.075 inches of travel of the free end. Referring to  FIG. 6 , the combination of the proposed vibrating armature  26  and the spring element  44  can absorb about 10% less energy at the minimum deflection point and about 10% more energy at the maximum deflection point that a standard vibrating armature. In this manner, the combination of the proposed vibrating armature  26  and the spring element  44  can provide better control over the movement of the reciprocating blade  18  then a standard vibrating armature. Note that the above noted travel distances and spring rates are exemplary in nature, and others travel distances and spring rates are contemplated. 
     All references cited herein are expressly incorporated by reference in their entirety. 
     It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described herein above. In addition, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. A variety of modifications and variations are possible in light of the above teachings without departing from the scope and spirit of the invention, which is limited only by the following claims.